git.oblomov.eu Git - git/blob - diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "config.h"
   6 #include "tempfile.h"
   7 #include "quote.h"
   8 #include "diff.h"
   9 #include "diffcore.h"
  10 #include "delta.h"
  11 #include "xdiff-interface.h"
  12 #include "color.h"
  13 #include "attr.h"
  14 #include "run-command.h"
  15 #include "utf8.h"
  16 #include "object-store.h"
  17 #include "userdiff.h"
  18 #include "submodule-config.h"
  19 #include "submodule.h"
  20 #include "hashmap.h"
  21 #include "ll-merge.h"
  22 #include "string-list.h"
  23 #include "strvec.h"
  24 #include "graph.h"
  25 #include "packfile.h"
  26 #include "parse-options.h"
  27 #include "help.h"
  28 #include "promisor-remote.h"
  29
  30 #ifdef NO_FAST_WORKING_DIRECTORY
  31 #define FAST_WORKING_DIRECTORY 0
  32 #else
  33 #define FAST_WORKING_DIRECTORY 1
  34 #endif
  35
  36 static int diff_detect_rename_default;
  37 static int diff_indent_heuristic = 1;
  38 static int diff_rename_limit_default = 400;
  39 static int diff_suppress_blank_empty;
  40 static int diff_use_color_default = -1;
  41 static int diff_color_moved_default;
  42 static int diff_color_moved_ws_default;
  43 static int diff_context_default = 3;
  44 static int diff_interhunk_context_default;
  45 static const char *diff_word_regex_cfg;
  46 static const char *external_diff_cmd_cfg;
  47 static const char *diff_order_file_cfg;
  48 int diff_auto_refresh_index = 1;
  49 static int diff_mnemonic_prefix;
  50 static int diff_no_prefix;
  51 static int diff_relative;
  52 static int diff_stat_graph_width;
  53 static int diff_dirstat_permille_default = 30;
  54 static struct diff_options default_diff_options;
  55 static long diff_algorithm;
  56 static unsigned ws_error_highlight_default = WSEH_NEW;
  57
  58 static char diff_colors[][COLOR_MAXLEN] = {
  59         GIT_COLOR_RESET,
  60         GIT_COLOR_NORMAL,       /* CONTEXT */
  61         GIT_COLOR_BOLD,         /* METAINFO */
  62         GIT_COLOR_CYAN,         /* FRAGINFO */
  63         GIT_COLOR_RED,          /* OLD */
  64         GIT_COLOR_GREEN,        /* NEW */
  65         GIT_COLOR_YELLOW,       /* COMMIT */
  66         GIT_COLOR_BG_RED,       /* WHITESPACE */
  67         GIT_COLOR_NORMAL,       /* FUNCINFO */
  68         GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  69         GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  70         GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  71         GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  72         GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  73         GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  74         GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  75         GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  76         GIT_COLOR_FAINT,        /* CONTEXT_DIM */
  77         GIT_COLOR_FAINT_RED,    /* OLD_DIM */
  78         GIT_COLOR_FAINT_GREEN,  /* NEW_DIM */
  79         GIT_COLOR_BOLD,         /* CONTEXT_BOLD */
  80         GIT_COLOR_BOLD_RED,     /* OLD_BOLD */
  81         GIT_COLOR_BOLD_GREEN,   /* NEW_BOLD */
  82 };
  83
  84 static const char *color_diff_slots[] = {
  85         [DIFF_CONTEXT]                = "context",
  86         [DIFF_METAINFO]               = "meta",
  87         [DIFF_FRAGINFO]               = "frag",
  88         [DIFF_FILE_OLD]               = "old",
  89         [DIFF_FILE_NEW]               = "new",
  90         [DIFF_COMMIT]                 = "commit",
  91         [DIFF_WHITESPACE]             = "whitespace",
  92         [DIFF_FUNCINFO]               = "func",
  93         [DIFF_FILE_OLD_MOVED]         = "oldMoved",
  94         [DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
  95         [DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
  96         [DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
  97         [DIFF_FILE_NEW_MOVED]         = "newMoved",
  98         [DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
  99         [DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
 100         [DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
 101         [DIFF_CONTEXT_DIM]            = "contextDimmed",
 102         [DIFF_FILE_OLD_DIM]           = "oldDimmed",
 103         [DIFF_FILE_NEW_DIM]           = "newDimmed",
 104         [DIFF_CONTEXT_BOLD]           = "contextBold",
 105         [DIFF_FILE_OLD_BOLD]          = "oldBold",
 106         [DIFF_FILE_NEW_BOLD]          = "newBold",
 107 };
 108
 109 define_list_config_array_extra(color_diff_slots, {"plain"});
 110
 111 static int parse_diff_color_slot(const char *var)
 112 {
 113         if (!strcasecmp(var, "plain"))
 114                 return DIFF_CONTEXT;
 115         return LOOKUP_CONFIG(color_diff_slots, var);
 116 }
 117
 118 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 119                                 struct strbuf *errmsg)
 120 {
 121         char *params_copy = xstrdup(params_string);
 122         struct string_list params = STRING_LIST_INIT_NODUP;
 123         int ret = 0;
 124         int i;
 125
 126         if (*params_copy)
 127                 string_list_split_in_place(&params, params_copy, ',', -1);
 128         for (i = 0; i < params.nr; i++) {
 129                 const char *p = params.items[i].string;
 130                 if (!strcmp(p, "changes")) {
 131                         options->flags.dirstat_by_line = 0;
 132                         options->flags.dirstat_by_file = 0;
 133                 } else if (!strcmp(p, "lines")) {
 134                         options->flags.dirstat_by_line = 1;
 135                         options->flags.dirstat_by_file = 0;
 136                 } else if (!strcmp(p, "files")) {
 137                         options->flags.dirstat_by_line = 0;
 138                         options->flags.dirstat_by_file = 1;
 139                 } else if (!strcmp(p, "noncumulative")) {
 140                         options->flags.dirstat_cumulative = 0;
 141                 } else if (!strcmp(p, "cumulative")) {
 142                         options->flags.dirstat_cumulative = 1;
 143                 } else if (isdigit(*p)) {
 144                         char *end;
 145                         int permille = strtoul(p, &end, 10) * 10;
 146                         if (*end == '.' && isdigit(*++end)) {
 147                                 /* only use first digit */
 148                                 permille += *end - '0';
 149                                 /* .. and ignore any further digits */
 150                                 while (isdigit(*++end))
 151                                         ; /* nothing */
 152                         }
 153                         if (!*end)
 154                                 options->dirstat_permille = permille;
 155                         else {
 156                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 157                                             p);
 158                                 ret++;
 159                         }
 160                 } else {
 161                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 162                         ret++;
 163                 }
 164
 165         }
 166         string_list_clear(&params, 0);
 167         free(params_copy);
 168         return ret;
 169 }
 170
 171 static int parse_submodule_params(struct diff_options *options, const char *value)
 172 {
 173         if (!strcmp(value, "log"))
 174                 options->submodule_format = DIFF_SUBMODULE_LOG;
 175         else if (!strcmp(value, "short"))
 176                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 177         else if (!strcmp(value, "diff"))
 178                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 179         /*
 180          * Please update $__git_diff_submodule_formats in
 181          * git-completion.bash when you add new formats.
 182          */
 183         else
 184                 return -1;
 185         return 0;
 186 }
 187
 188 int git_config_rename(const char *var, const char *value)
 189 {
 190         if (!value)
 191                 return DIFF_DETECT_RENAME;
 192         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 193                 return  DIFF_DETECT_COPY;
 194         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 195 }
 196
 197 long parse_algorithm_value(const char *value)
 198 {
 199         if (!value)
 200                 return -1;
 201         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 202                 return 0;
 203         else if (!strcasecmp(value, "minimal"))
 204                 return XDF_NEED_MINIMAL;
 205         else if (!strcasecmp(value, "patience"))
 206                 return XDF_PATIENCE_DIFF;
 207         else if (!strcasecmp(value, "histogram"))
 208                 return XDF_HISTOGRAM_DIFF;
 209         /*
 210          * Please update $__git_diff_algorithms in git-completion.bash
 211          * when you add new algorithms.
 212          */
 213         return -1;
 214 }
 215
 216 static int parse_one_token(const char **arg, const char *token)
 217 {
 218         const char *rest;
 219         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 220                 *arg = rest;
 221                 return 1;
 222         }
 223         return 0;
 224 }
 225
 226 static int parse_ws_error_highlight(const char *arg)
 227 {
 228         const char *orig_arg = arg;
 229         unsigned val = 0;
 230
 231         while (*arg) {
 232                 if (parse_one_token(&arg, "none"))
 233                         val = 0;
 234                 else if (parse_one_token(&arg, "default"))
 235                         val = WSEH_NEW;
 236                 else if (parse_one_token(&arg, "all"))
 237                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 238                 else if (parse_one_token(&arg, "new"))
 239                         val |= WSEH_NEW;
 240                 else if (parse_one_token(&arg, "old"))
 241                         val |= WSEH_OLD;
 242                 else if (parse_one_token(&arg, "context"))
 243                         val |= WSEH_CONTEXT;
 244                 else {
 245                         return -1 - (int)(arg - orig_arg);
 246                 }
 247                 if (*arg)
 248                         arg++;
 249         }
 250         return val;
 251 }
 252
 253 /*
 254  * These are to give UI layer defaults.
 255  * The core-level commands such as git-diff-files should
 256  * never be affected by the setting of diff.renames
 257  * the user happens to have in the configuration file.
 258  */
 259 void init_diff_ui_defaults(void)
 260 {
 261         diff_detect_rename_default = DIFF_DETECT_RENAME;
 262 }
 263
 264 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 265 {
 266         if (!strcmp(var, "diff.indentheuristic"))
 267                 diff_indent_heuristic = git_config_bool(var, value);
 268         return 0;
 269 }
 270
 271 static int parse_color_moved(const char *arg)
 272 {
 273         switch (git_parse_maybe_bool(arg)) {
 274         case 0:
 275                 return COLOR_MOVED_NO;
 276         case 1:
 277                 return COLOR_MOVED_DEFAULT;
 278         default:
 279                 break;
 280         }
 281
 282         if (!strcmp(arg, "no"))
 283                 return COLOR_MOVED_NO;
 284         else if (!strcmp(arg, "plain"))
 285                 return COLOR_MOVED_PLAIN;
 286         else if (!strcmp(arg, "blocks"))
 287                 return COLOR_MOVED_BLOCKS;
 288         else if (!strcmp(arg, "zebra"))
 289                 return COLOR_MOVED_ZEBRA;
 290         else if (!strcmp(arg, "default"))
 291                 return COLOR_MOVED_DEFAULT;
 292         else if (!strcmp(arg, "dimmed-zebra"))
 293                 return COLOR_MOVED_ZEBRA_DIM;
 294         else if (!strcmp(arg, "dimmed_zebra"))
 295                 return COLOR_MOVED_ZEBRA_DIM;
 296         else
 297                 return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed-zebra', 'plain'"));
 298 }
 299
 300 static unsigned parse_color_moved_ws(const char *arg)
 301 {
 302         int ret = 0;
 303         struct string_list l = STRING_LIST_INIT_DUP;
 304         struct string_list_item *i;
 305
 306         string_list_split(&l, arg, ',', -1);
 307
 308         for_each_string_list_item(i, &l) {
 309                 struct strbuf sb = STRBUF_INIT;
 310                 strbuf_addstr(&sb, i->string);
 311                 strbuf_trim(&sb);
 312
 313                 if (!strcmp(sb.buf, "no"))
 314                         ret = 0;
 315                 else if (!strcmp(sb.buf, "ignore-space-change"))
 316                         ret |= XDF_IGNORE_WHITESPACE_CHANGE;
 317                 else if (!strcmp(sb.buf, "ignore-space-at-eol"))
 318                         ret |= XDF_IGNORE_WHITESPACE_AT_EOL;
 319                 else if (!strcmp(sb.buf, "ignore-all-space"))
 320                         ret |= XDF_IGNORE_WHITESPACE;
 321                 else if (!strcmp(sb.buf, "allow-indentation-change"))
 322                         ret |= COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE;
 323                 else {
 324                         ret |= COLOR_MOVED_WS_ERROR;
 325                         error(_("unknown color-moved-ws mode '%s', possible values are 'ignore-space-change', 'ignore-space-at-eol', 'ignore-all-space', 'allow-indentation-change'"), sb.buf);
 326                 }
 327
 328                 strbuf_release(&sb);
 329         }
 330
 331         if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
 332             (ret & XDF_WHITESPACE_FLAGS)) {
 333                 error(_("color-moved-ws: allow-indentation-change cannot be combined with other whitespace modes"));
 334                 ret |= COLOR_MOVED_WS_ERROR;
 335         }
 336
 337         string_list_clear(&l, 0);
 338
 339         return ret;
 340 }
 341
 342 int git_diff_ui_config(const char *var, const char *value, void *cb)
 343 {
 344         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 345                 diff_use_color_default = git_config_colorbool(var, value);
 346                 return 0;
 347         }
 348         if (!strcmp(var, "diff.colormoved")) {
 349                 int cm = parse_color_moved(value);
 350                 if (cm < 0)
 351                         return -1;
 352                 diff_color_moved_default = cm;
 353                 return 0;
 354         }
 355         if (!strcmp(var, "diff.colormovedws")) {
 356                 unsigned cm = parse_color_moved_ws(value);
 357                 if (cm & COLOR_MOVED_WS_ERROR)
 358                         return -1;
 359                 diff_color_moved_ws_default = cm;
 360                 return 0;
 361         }
 362         if (!strcmp(var, "diff.context")) {
 363                 diff_context_default = git_config_int(var, value);
 364                 if (diff_context_default < 0)
 365                         return -1;
 366                 return 0;
 367         }
 368         if (!strcmp(var, "diff.interhunkcontext")) {
 369                 diff_interhunk_context_default = git_config_int(var, value);
 370                 if (diff_interhunk_context_default < 0)
 371                         return -1;
 372                 return 0;
 373         }
 374         if (!strcmp(var, "diff.renames")) {
 375                 diff_detect_rename_default = git_config_rename(var, value);
 376                 return 0;
 377         }
 378         if (!strcmp(var, "diff.autorefreshindex")) {
 379                 diff_auto_refresh_index = git_config_bool(var, value);
 380                 return 0;
 381         }
 382         if (!strcmp(var, "diff.mnemonicprefix")) {
 383                 diff_mnemonic_prefix = git_config_bool(var, value);
 384                 return 0;
 385         }
 386         if (!strcmp(var, "diff.noprefix")) {
 387                 diff_no_prefix = git_config_bool(var, value);
 388                 return 0;
 389         }
 390         if (!strcmp(var, "diff.relative")) {
 391                 diff_relative = git_config_bool(var, value);
 392                 return 0;
 393         }
 394         if (!strcmp(var, "diff.statgraphwidth")) {
 395                 diff_stat_graph_width = git_config_int(var, value);
 396                 return 0;
 397         }
 398         if (!strcmp(var, "diff.external"))
 399                 return git_config_string(&external_diff_cmd_cfg, var, value);
 400         if (!strcmp(var, "diff.wordregex"))
 401                 return git_config_string(&diff_word_regex_cfg, var, value);
 402         if (!strcmp(var, "diff.orderfile"))
 403                 return git_config_pathname(&diff_order_file_cfg, var, value);
 404
 405         if (!strcmp(var, "diff.ignoresubmodules"))
 406                 handle_ignore_submodules_arg(&default_diff_options, value);
 407
 408         if (!strcmp(var, "diff.submodule")) {
 409                 if (parse_submodule_params(&default_diff_options, value))
 410                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 411                                 value);
 412                 return 0;
 413         }
 414
 415         if (!strcmp(var, "diff.algorithm")) {
 416                 diff_algorithm = parse_algorithm_value(value);
 417                 if (diff_algorithm < 0)
 418                         return -1;
 419                 return 0;
 420         }
 421
 422         if (git_color_config(var, value, cb) < 0)
 423                 return -1;
 424
 425         return git_diff_basic_config(var, value, cb);
 426 }
 427
 428 int git_diff_basic_config(const char *var, const char *value, void *cb)
 429 {
 430         const char *name;
 431
 432         if (!strcmp(var, "diff.renamelimit")) {
 433                 diff_rename_limit_default = git_config_int(var, value);
 434                 return 0;
 435         }
 436
 437         if (userdiff_config(var, value) < 0)
 438                 return -1;
 439
 440         if (skip_prefix(var, "diff.color.", &name) ||
 441             skip_prefix(var, "color.diff.", &name)) {
 442                 int slot = parse_diff_color_slot(name);
 443                 if (slot < 0)
 444                         return 0;
 445                 if (!value)
 446                         return config_error_nonbool(var);
 447                 return color_parse(value, diff_colors[slot]);
 448         }
 449
 450         if (!strcmp(var, "diff.wserrorhighlight")) {
 451                 int val = parse_ws_error_highlight(value);
 452                 if (val < 0)
 453                         return -1;
 454                 ws_error_highlight_default = val;
 455                 return 0;
 456         }
 457
 458         /* like GNU diff's --suppress-blank-empty option  */
 459         if (!strcmp(var, "diff.suppressblankempty") ||
 460                         /* for backwards compatibility */
 461                         !strcmp(var, "diff.suppress-blank-empty")) {
 462                 diff_suppress_blank_empty = git_config_bool(var, value);
 463                 return 0;
 464         }
 465
 466         if (!strcmp(var, "diff.dirstat")) {
 467                 struct strbuf errmsg = STRBUF_INIT;
 468                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 469                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 470                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 471                                 errmsg.buf);
 472                 strbuf_release(&errmsg);
 473                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 474                 return 0;
 475         }
 476
 477         if (git_diff_heuristic_config(var, value, cb) < 0)
 478                 return -1;
 479
 480         return git_default_config(var, value, cb);
 481 }
 482
 483 static char *quote_two(const char *one, const char *two)
 484 {
 485         int need_one = quote_c_style(one, NULL, NULL, CQUOTE_NODQ);
 486         int need_two = quote_c_style(two, NULL, NULL, CQUOTE_NODQ);
 487         struct strbuf res = STRBUF_INIT;
 488
 489         if (need_one + need_two) {
 490                 strbuf_addch(&res, '"');
 491                 quote_c_style(one, &res, NULL, CQUOTE_NODQ);
 492                 quote_c_style(two, &res, NULL, CQUOTE_NODQ);
 493                 strbuf_addch(&res, '"');
 494         } else {
 495                 strbuf_addstr(&res, one);
 496                 strbuf_addstr(&res, two);
 497         }
 498         return strbuf_detach(&res, NULL);
 499 }
 500
 501 static const char *external_diff(void)
 502 {
 503         static const char *external_diff_cmd = NULL;
 504         static int done_preparing = 0;
 505
 506         if (done_preparing)
 507                 return external_diff_cmd;
 508         external_diff_cmd = xstrdup_or_null(getenv("GIT_EXTERNAL_DIFF"));
 509         if (!external_diff_cmd)
 510                 external_diff_cmd = external_diff_cmd_cfg;
 511         done_preparing = 1;
 512         return external_diff_cmd;
 513 }
 514
 515 /*
 516  * Keep track of files used for diffing. Sometimes such an entry
 517  * refers to a temporary file, sometimes to an existing file, and
 518  * sometimes to "/dev/null".
 519  */
 520 static struct diff_tempfile {
 521         /*
 522          * filename external diff should read from, or NULL if this
 523          * entry is currently not in use:
 524          */
 525         const char *name;
 526
 527         char hex[GIT_MAX_HEXSZ + 1];
 528         char mode[10];
 529
 530         /*
 531          * If this diff_tempfile instance refers to a temporary file,
 532          * this tempfile object is used to manage its lifetime.
 533          */
 534         struct tempfile *tempfile;
 535 } diff_temp[2];
 536
 537 struct emit_callback {
 538         int color_diff;
 539         unsigned ws_rule;
 540         int blank_at_eof_in_preimage;
 541         int blank_at_eof_in_postimage;
 542         int lno_in_preimage;
 543         int lno_in_postimage;
 544         const char **label_path;
 545         struct diff_words_data *diff_words;
 546         struct diff_options *opt;
 547         struct strbuf *header;
 548 };
 549
 550 static int count_lines(const char *data, int size)
 551 {
 552         int count, ch, completely_empty = 1, nl_just_seen = 0;
 553         count = 0;
 554         while (0 < size--) {
 555                 ch = *data++;
 556                 if (ch == '\n') {
 557                         count++;
 558                         nl_just_seen = 1;
 559                         completely_empty = 0;
 560                 }
 561                 else {
 562                         nl_just_seen = 0;
 563                         completely_empty = 0;
 564                 }
 565         }
 566         if (completely_empty)
 567                 return 0;
 568         if (!nl_just_seen)
 569                 count++; /* no trailing newline */
 570         return count;
 571 }
 572
 573 static int fill_mmfile(struct repository *r, mmfile_t *mf,
 574                        struct diff_filespec *one)
 575 {
 576         if (!DIFF_FILE_VALID(one)) {
 577                 mf->ptr = (char *)""; /* does not matter */
 578                 mf->size = 0;
 579                 return 0;
 580         }
 581         else if (diff_populate_filespec(r, one, NULL))
 582                 return -1;
 583
 584         mf->ptr = one->data;
 585         mf->size = one->size;
 586         return 0;
 587 }
 588
 589 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 590 static unsigned long diff_filespec_size(struct repository *r,
 591                                         struct diff_filespec *one)
 592 {
 593         struct diff_populate_filespec_options dpf_options = {
 594                 .check_size_only = 1,
 595         };
 596
 597         if (!DIFF_FILE_VALID(one))
 598                 return 0;
 599         diff_populate_filespec(r, one, &dpf_options);
 600         return one->size;
 601 }
 602
 603 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 604 {
 605         char *ptr = mf->ptr;
 606         long size = mf->size;
 607         int cnt = 0;
 608
 609         if (!size)
 610                 return cnt;
 611         ptr += size - 1; /* pointing at the very end */
 612         if (*ptr != '\n')
 613                 ; /* incomplete line */
 614         else
 615                 ptr--; /* skip the last LF */
 616         while (mf->ptr < ptr) {
 617                 char *prev_eol;
 618                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 619                         if (*prev_eol == '\n')
 620                                 break;
 621                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 622                         break;
 623                 cnt++;
 624                 ptr = prev_eol - 1;
 625         }
 626         return cnt;
 627 }
 628
 629 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 630                                struct emit_callback *ecbdata)
 631 {
 632         int l1, l2, at;
 633         unsigned ws_rule = ecbdata->ws_rule;
 634         l1 = count_trailing_blank(mf1, ws_rule);
 635         l2 = count_trailing_blank(mf2, ws_rule);
 636         if (l2 <= l1) {
 637                 ecbdata->blank_at_eof_in_preimage = 0;
 638                 ecbdata->blank_at_eof_in_postimage = 0;
 639                 return;
 640         }
 641         at = count_lines(mf1->ptr, mf1->size);
 642         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 643
 644         at = count_lines(mf2->ptr, mf2->size);
 645         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 646 }
 647
 648 static void emit_line_0(struct diff_options *o,
 649                         const char *set_sign, const char *set, unsigned reverse, const char *reset,
 650                         int first, const char *line, int len)
 651 {
 652         int has_trailing_newline, has_trailing_carriage_return;
 653         int needs_reset = 0; /* at the end of the line */
 654         FILE *file = o->file;
 655
 656         fputs(diff_line_prefix(o), file);
 657
 658         has_trailing_newline = (len > 0 && line[len-1] == '\n');
 659         if (has_trailing_newline)
 660                 len--;
 661
 662         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 663         if (has_trailing_carriage_return)
 664                 len--;
 665
 666         if (!len && !first)
 667                 goto end_of_line;
 668
 669         if (reverse && want_color(o->use_color)) {
 670                 fputs(GIT_COLOR_REVERSE, file);
 671                 needs_reset = 1;
 672         }
 673
 674         if (set_sign) {
 675                 fputs(set_sign, file);
 676                 needs_reset = 1;
 677         }
 678
 679         if (first)
 680                 fputc(first, file);
 681
 682         if (!len)
 683                 goto end_of_line;
 684
 685         if (set) {
 686                 if (set_sign && set != set_sign)
 687                         fputs(reset, file);
 688                 fputs(set, file);
 689                 needs_reset = 1;
 690         }
 691         fwrite(line, len, 1, file);
 692         needs_reset = 1; /* 'line' may contain color codes. */
 693
 694 end_of_line:
 695         if (needs_reset)
 696                 fputs(reset, file);
 697         if (has_trailing_carriage_return)
 698                 fputc('\r', file);
 699         if (has_trailing_newline)
 700                 fputc('\n', file);
 701 }
 702
 703 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 704                       const char *line, int len)
 705 {
 706         emit_line_0(o, set, NULL, 0, reset, 0, line, len);
 707 }
 708
 709 enum diff_symbol {
 710         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 711         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 712         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 713         DIFF_SYMBOL_BINARY_DIFF_BODY,
 714         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 715         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 716         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 717         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 718         DIFF_SYMBOL_STATS_LINE,
 719         DIFF_SYMBOL_WORD_DIFF,
 720         DIFF_SYMBOL_STAT_SEP,
 721         DIFF_SYMBOL_SUMMARY,
 722         DIFF_SYMBOL_SUBMODULE_ADD,
 723         DIFF_SYMBOL_SUBMODULE_DEL,
 724         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 725         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 726         DIFF_SYMBOL_SUBMODULE_HEADER,
 727         DIFF_SYMBOL_SUBMODULE_ERROR,
 728         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 729         DIFF_SYMBOL_REWRITE_DIFF,
 730         DIFF_SYMBOL_BINARY_FILES,
 731         DIFF_SYMBOL_HEADER,
 732         DIFF_SYMBOL_FILEPAIR_PLUS,
 733         DIFF_SYMBOL_FILEPAIR_MINUS,
 734         DIFF_SYMBOL_WORDS_PORCELAIN,
 735         DIFF_SYMBOL_WORDS,
 736         DIFF_SYMBOL_CONTEXT,
 737         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 738         DIFF_SYMBOL_PLUS,
 739         DIFF_SYMBOL_MINUS,
 740         DIFF_SYMBOL_NO_LF_EOF,
 741         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 742         DIFF_SYMBOL_CONTEXT_MARKER,
 743         DIFF_SYMBOL_SEPARATOR
 744 };
 745 /*
 746  * Flags for content lines:
 747  * 0..12 are whitespace rules
 748  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 749  * 16 is marking if the line is blank at EOF
 750  */
 751 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 752 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 753 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 754 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 755 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 756
 757 /*
 758  * This struct is used when we need to buffer the output of the diff output.
 759  *
 760  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 761  * into the pre/post image file. This pointer could be a union with the
 762  * line pointer. By storing an offset into the file instead of the literal line,
 763  * we can decrease the memory footprint for the buffered output. At first we
 764  * may want to only have indirection for the content lines, but we could also
 765  * enhance the state for emitting prefabricated lines, e.g. the similarity
 766  * score line or hunk/file headers would only need to store a number or path
 767  * and then the output can be constructed later on depending on state.
 768  */
 769 struct emitted_diff_symbol {
 770         const char *line;
 771         int len;
 772         int flags;
 773         int indent_off;   /* Offset to first non-whitespace character */
 774         int indent_width; /* The visual width of the indentation */
 775         enum diff_symbol s;
 776 };
 777 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 778
 779 struct emitted_diff_symbols {
 780         struct emitted_diff_symbol *buf;
 781         int nr, alloc;
 782 };
 783 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 784
 785 static void append_emitted_diff_symbol(struct diff_options *o,
 786                                        struct emitted_diff_symbol *e)
 787 {
 788         struct emitted_diff_symbol *f;
 789
 790         ALLOC_GROW(o->emitted_symbols->buf,
 791                    o->emitted_symbols->nr + 1,
 792                    o->emitted_symbols->alloc);
 793         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 794
 795         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 796         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 797 }
 798
 799 struct moved_entry {
 800         struct hashmap_entry ent;
 801         const struct emitted_diff_symbol *es;
 802         struct moved_entry *next_line;
 803 };
 804
 805 struct moved_block {
 806         struct moved_entry *match;
 807         int wsd; /* The whitespace delta of this block */
 808 };
 809
 810 static void moved_block_clear(struct moved_block *b)
 811 {
 812         memset(b, 0, sizeof(*b));
 813 }
 814
 815 #define INDENT_BLANKLINE INT_MIN
 816
 817 static void fill_es_indent_data(struct emitted_diff_symbol *es)
 818 {
 819         unsigned int off = 0, i;
 820         int width = 0, tab_width = es->flags & WS_TAB_WIDTH_MASK;
 821         const char *s = es->line;
 822         const int len = es->len;
 823
 824         /* skip any \v \f \r at start of indentation */
 825         while (s[off] == '\f' || s[off] == '\v' ||
 826                (s[off] == '\r' && off < len - 1))
 827                 off++;
 828
 829         /* calculate the visual width of indentation */
 830         while(1) {
 831                 if (s[off] == ' ') {
 832                         width++;
 833                         off++;
 834                 } else if (s[off] == '\t') {
 835                         width += tab_width - (width % tab_width);
 836                         while (s[++off] == '\t')
 837                                 width += tab_width;
 838                 } else {
 839                         break;
 840                 }
 841         }
 842
 843         /* check if this line is blank */
 844         for (i = off; i < len; i++)
 845                 if (!isspace(s[i]))
 846                     break;
 847
 848         if (i == len) {
 849                 es->indent_width = INDENT_BLANKLINE;
 850                 es->indent_off = len;
 851         } else {
 852                 es->indent_off = off;
 853                 es->indent_width = width;
 854         }
 855 }
 856
 857 static int compute_ws_delta(const struct emitted_diff_symbol *a,
 858                             const struct emitted_diff_symbol *b,
 859                             int *out)
 860 {
 861         int a_len = a->len,
 862             b_len = b->len,
 863             a_off = a->indent_off,
 864             a_width = a->indent_width,
 865             b_off = b->indent_off,
 866             b_width = b->indent_width;
 867         int delta;
 868
 869         if (a_width == INDENT_BLANKLINE && b_width == INDENT_BLANKLINE) {
 870                 *out = INDENT_BLANKLINE;
 871                 return 1;
 872         }
 873
 874         if (a->s == DIFF_SYMBOL_PLUS)
 875                 delta = a_width - b_width;
 876         else
 877                 delta = b_width - a_width;
 878
 879         if (a_len - a_off != b_len - b_off ||
 880             memcmp(a->line + a_off, b->line + b_off, a_len - a_off))
 881                 return 0;
 882
 883         *out = delta;
 884
 885         return 1;
 886 }
 887
 888 static int cmp_in_block_with_wsd(const struct diff_options *o,
 889                                  const struct moved_entry *cur,
 890                                  const struct moved_entry *match,
 891                                  struct moved_block *pmb,
 892                                  int n)
 893 {
 894         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 895         int al = cur->es->len, bl = match->es->len, cl = l->len;
 896         const char *a = cur->es->line,
 897                    *b = match->es->line,
 898                    *c = l->line;
 899         int a_off = cur->es->indent_off,
 900             a_width = cur->es->indent_width,
 901             c_off = l->indent_off,
 902             c_width = l->indent_width;
 903         int delta;
 904
 905         /*
 906          * We need to check if 'cur' is equal to 'match'.  As those
 907          * are from the same (+/-) side, we do not need to adjust for
 908          * indent changes. However these were found using fuzzy
 909          * matching so we do have to check if they are equal. Here we
 910          * just check the lengths. We delay calling memcmp() to check
 911          * the contents until later as if the length comparison for a
 912          * and c fails we can avoid the call all together.
 913          */
 914         if (al != bl)
 915                 return 1;
 916
 917         /* If 'l' and 'cur' are both blank then they match. */
 918         if (a_width == INDENT_BLANKLINE && c_width == INDENT_BLANKLINE)
 919                 return 0;
 920
 921         /*
 922          * The indent changes of the block are known and stored in pmb->wsd;
 923          * however we need to check if the indent changes of the current line
 924          * match those of the current block and that the text of 'l' and 'cur'
 925          * after the indentation match.
 926          */
 927         if (cur->es->s == DIFF_SYMBOL_PLUS)
 928                 delta = a_width - c_width;
 929         else
 930                 delta = c_width - a_width;
 931
 932         /*
 933          * If the previous lines of this block were all blank then set its
 934          * whitespace delta.
 935          */
 936         if (pmb->wsd == INDENT_BLANKLINE)
 937                 pmb->wsd = delta;
 938
 939         return !(delta == pmb->wsd && al - a_off == cl - c_off &&
 940                  !memcmp(a, b, al) && !
 941                  memcmp(a + a_off, c + c_off, al - a_off));
 942 }
 943
 944 static int moved_entry_cmp(const void *hashmap_cmp_fn_data,
 945                            const struct hashmap_entry *eptr,
 946                            const struct hashmap_entry *entry_or_key,
 947                            const void *keydata)
 948 {
 949         const struct diff_options *diffopt = hashmap_cmp_fn_data;
 950         const struct moved_entry *a, *b;
 951         unsigned flags = diffopt->color_moved_ws_handling
 952                          & XDF_WHITESPACE_FLAGS;
 953
 954         a = container_of(eptr, const struct moved_entry, ent);
 955         b = container_of(entry_or_key, const struct moved_entry, ent);
 956
 957         if (diffopt->color_moved_ws_handling &
 958             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
 959                 /*
 960                  * As there is not specific white space config given,
 961                  * we'd need to check for a new block, so ignore all
 962                  * white space. The setup of the white space
 963                  * configuration for the next block is done else where
 964                  */
 965                 flags |= XDF_IGNORE_WHITESPACE;
 966
 967         return !xdiff_compare_lines(a->es->line, a->es->len,
 968                                     b->es->line, b->es->len,
 969                                     flags);
 970 }
 971
 972 static struct moved_entry *prepare_entry(struct diff_options *o,
 973                                          int line_no)
 974 {
 975         struct moved_entry *ret = xmalloc(sizeof(*ret));
 976         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 977         unsigned flags = o->color_moved_ws_handling & XDF_WHITESPACE_FLAGS;
 978         unsigned int hash = xdiff_hash_string(l->line, l->len, flags);
 979
 980         hashmap_entry_init(&ret->ent, hash);
 981         ret->es = l;
 982         ret->next_line = NULL;
 983
 984         return ret;
 985 }
 986
 987 static void add_lines_to_move_detection(struct diff_options *o,
 988                                         struct hashmap *add_lines,
 989                                         struct hashmap *del_lines)
 990 {
 991         struct moved_entry *prev_line = NULL;
 992
 993         int n;
 994         for (n = 0; n < o->emitted_symbols->nr; n++) {
 995                 struct hashmap *hm;
 996                 struct moved_entry *key;
 997
 998                 switch (o->emitted_symbols->buf[n].s) {
 999                 case DIFF_SYMBOL_PLUS:
1000                         hm = add_lines;
1001                         break;
1002                 case DIFF_SYMBOL_MINUS:
1003                         hm = del_lines;
1004                         break;
1005                 default:
1006                         prev_line = NULL;
1007                         continue;
1008                 }
1009
1010                 if (o->color_moved_ws_handling &
1011                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
1012                         fill_es_indent_data(&o->emitted_symbols->buf[n]);
1013                 key = prepare_entry(o, n);
1014                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
1015                         prev_line->next_line = key;
1016
1017                 hashmap_add(hm, &key->ent);
1018                 prev_line = key;
1019         }
1020 }
1021
1022 static void pmb_advance_or_null(struct diff_options *o,
1023                                 struct moved_entry *match,
1024                                 struct hashmap *hm,
1025                                 struct moved_block *pmb,
1026                                 int pmb_nr)
1027 {
1028         int i;
1029         for (i = 0; i < pmb_nr; i++) {
1030                 struct moved_entry *prev = pmb[i].match;
1031                 struct moved_entry *cur = (prev && prev->next_line) ?
1032                                 prev->next_line : NULL;
1033                 if (cur && !hm->cmpfn(o, &cur->ent, &match->ent, NULL)) {
1034                         pmb[i].match = cur;
1035                 } else {
1036                         pmb[i].match = NULL;
1037                 }
1038         }
1039 }
1040
1041 static void pmb_advance_or_null_multi_match(struct diff_options *o,
1042                                             struct moved_entry *match,
1043                                             struct hashmap *hm,
1044                                             struct moved_block *pmb,
1045                                             int pmb_nr, int n)
1046 {
1047         int i;
1048         char *got_match = xcalloc(1, pmb_nr);
1049
1050         hashmap_for_each_entry_from(hm, match, ent) {
1051                 for (i = 0; i < pmb_nr; i++) {
1052                         struct moved_entry *prev = pmb[i].match;
1053                         struct moved_entry *cur = (prev && prev->next_line) ?
1054                                         prev->next_line : NULL;
1055                         if (!cur)
1056                                 continue;
1057                         if (!cmp_in_block_with_wsd(o, cur, match, &pmb[i], n))
1058                                 got_match[i] |= 1;
1059                 }
1060         }
1061
1062         for (i = 0; i < pmb_nr; i++) {
1063                 if (got_match[i]) {
1064                         /* Advance to the next line */
1065                         pmb[i].match = pmb[i].match->next_line;
1066                 } else {
1067                         moved_block_clear(&pmb[i]);
1068                 }
1069         }
1070
1071         free(got_match);
1072 }
1073
1074 static int shrink_potential_moved_blocks(struct moved_block *pmb,
1075                                          int pmb_nr)
1076 {
1077         int lp, rp;
1078
1079         /* Shrink the set of potential block to the remaining running */
1080         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
1081                 while (lp < pmb_nr && pmb[lp].match)
1082                         lp++;
1083                 /* lp points at the first NULL now */
1084
1085                 while (rp > -1 && !pmb[rp].match)
1086                         rp--;
1087                 /* rp points at the last non-NULL */
1088
1089                 if (lp < pmb_nr && rp > -1 && lp < rp) {
1090                         pmb[lp] = pmb[rp];
1091                         memset(&pmb[rp], 0, sizeof(pmb[rp]));
1092                         rp--;
1093                         lp++;
1094                 }
1095         }
1096
1097         /* Remember the number of running sets */
1098         return rp + 1;
1099 }
1100
1101 /*
1102  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
1103  *
1104  * Otherwise, if the last block has fewer alphanumeric characters than
1105  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
1106  * that block.
1107  *
1108  * The last block consists of the (n - block_length)'th line up to but not
1109  * including the nth line.
1110  *
1111  * Returns 0 if the last block is empty or is unset by this function, non zero
1112  * otherwise.
1113  *
1114  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
1115  * Think of a way to unify them.
1116  */
1117 static int adjust_last_block(struct diff_options *o, int n, int block_length)
1118 {
1119         int i, alnum_count = 0;
1120         if (o->color_moved == COLOR_MOVED_PLAIN)
1121                 return block_length;
1122         for (i = 1; i < block_length + 1; i++) {
1123                 const char *c = o->emitted_symbols->buf[n - i].line;
1124                 for (; *c; c++) {
1125                         if (!isalnum(*c))
1126                                 continue;
1127                         alnum_count++;
1128                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
1129                                 return 1;
1130                 }
1131         }
1132         for (i = 1; i < block_length + 1; i++)
1133                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
1134         return 0;
1135 }
1136
1137 /* Find blocks of moved code, delegate actual coloring decision to helper */
1138 static void mark_color_as_moved(struct diff_options *o,
1139                                 struct hashmap *add_lines,
1140                                 struct hashmap *del_lines)
1141 {
1142         struct moved_block *pmb = NULL; /* potentially moved blocks */
1143         int pmb_nr = 0, pmb_alloc = 0;
1144         int n, flipped_block = 0, block_length = 0;
1145
1146
1147         for (n = 0; n < o->emitted_symbols->nr; n++) {
1148                 struct hashmap *hm = NULL;
1149                 struct moved_entry *key;
1150                 struct moved_entry *match = NULL;
1151                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1152                 enum diff_symbol last_symbol = 0;
1153
1154                 switch (l->s) {
1155                 case DIFF_SYMBOL_PLUS:
1156                         hm = del_lines;
1157                         key = prepare_entry(o, n);
1158                         match = hashmap_get_entry(hm, key, ent, NULL);
1159                         free(key);
1160                         break;
1161                 case DIFF_SYMBOL_MINUS:
1162                         hm = add_lines;
1163                         key = prepare_entry(o, n);
1164                         match = hashmap_get_entry(hm, key, ent, NULL);
1165                         free(key);
1166                         break;
1167                 default:
1168                         flipped_block = 0;
1169                 }
1170
1171                 if (!match) {
1172                         int i;
1173
1174                         adjust_last_block(o, n, block_length);
1175                         for(i = 0; i < pmb_nr; i++)
1176                                 moved_block_clear(&pmb[i]);
1177                         pmb_nr = 0;
1178                         block_length = 0;
1179                         flipped_block = 0;
1180                         last_symbol = l->s;
1181                         continue;
1182                 }
1183
1184                 if (o->color_moved == COLOR_MOVED_PLAIN) {
1185                         last_symbol = l->s;
1186                         l->flags |= DIFF_SYMBOL_MOVED_LINE;
1187                         continue;
1188                 }
1189
1190                 if (o->color_moved_ws_handling &
1191                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
1192                         pmb_advance_or_null_multi_match(o, match, hm, pmb, pmb_nr, n);
1193                 else
1194                         pmb_advance_or_null(o, match, hm, pmb, pmb_nr);
1195
1196                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
1197
1198                 if (pmb_nr == 0) {
1199                         /*
1200                          * The current line is the start of a new block.
1201                          * Setup the set of potential blocks.
1202                          */
1203                         hashmap_for_each_entry_from(hm, match, ent) {
1204                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
1205                                 if (o->color_moved_ws_handling &
1206                                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) {
1207                                         if (compute_ws_delta(l, match->es,
1208                                                              &pmb[pmb_nr].wsd))
1209                                                 pmb[pmb_nr++].match = match;
1210                                 } else {
1211                                         pmb[pmb_nr].wsd = 0;
1212                                         pmb[pmb_nr++].match = match;
1213                                 }
1214                         }
1215
1216                         if (adjust_last_block(o, n, block_length) &&
1217                             pmb_nr && last_symbol != l->s)
1218                                 flipped_block = (flipped_block + 1) % 2;
1219                         else
1220                                 flipped_block = 0;
1221
1222                         block_length = 0;
1223                 }
1224
1225                 if (pmb_nr) {
1226                         block_length++;
1227                         l->flags |= DIFF_SYMBOL_MOVED_LINE;
1228                         if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
1229                                 l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
1230                 }
1231                 last_symbol = l->s;
1232         }
1233         adjust_last_block(o, n, block_length);
1234
1235         for(n = 0; n < pmb_nr; n++)
1236                 moved_block_clear(&pmb[n]);
1237         free(pmb);
1238 }
1239
1240 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
1241   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
1242 static void dim_moved_lines(struct diff_options *o)
1243 {
1244         int n;
1245         for (n = 0; n < o->emitted_symbols->nr; n++) {
1246                 struct emitted_diff_symbol *prev = (n != 0) ?
1247                                 &o->emitted_symbols->buf[n - 1] : NULL;
1248                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1249                 struct emitted_diff_symbol *next =
1250                                 (n < o->emitted_symbols->nr - 1) ?
1251                                 &o->emitted_symbols->buf[n + 1] : NULL;
1252
1253                 /* Not a plus or minus line? */
1254                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
1255                         continue;
1256
1257                 /* Not a moved line? */
1258                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
1259                         continue;
1260
1261                 /*
1262                  * If prev or next are not a plus or minus line,
1263                  * pretend they don't exist
1264                  */
1265                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
1266                             prev->s != DIFF_SYMBOL_MINUS)
1267                         prev = NULL;
1268                 if (next && next->s != DIFF_SYMBOL_PLUS &&
1269                             next->s != DIFF_SYMBOL_MINUS)
1270                         next = NULL;
1271
1272                 /* Inside a block? */
1273                 if ((prev &&
1274                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1275                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
1276                     (next &&
1277                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1278                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
1279                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1280                         continue;
1281                 }
1282
1283                 /* Check if we are at an interesting bound: */
1284                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
1285                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1286                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1287                         continue;
1288                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
1289                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1290                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1291                         continue;
1292
1293                 /*
1294                  * The boundary to prev and next are not interesting,
1295                  * so this line is not interesting as a whole
1296                  */
1297                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1298         }
1299 }
1300
1301 static void emit_line_ws_markup(struct diff_options *o,
1302                                 const char *set_sign, const char *set,
1303                                 const char *reset,
1304                                 int sign_index, const char *line, int len,
1305                                 unsigned ws_rule, int blank_at_eof)
1306 {
1307         const char *ws = NULL;
1308         int sign = o->output_indicators[sign_index];
1309
1310         if (o->ws_error_highlight & ws_rule) {
1311                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
1312                 if (!*ws)
1313                         ws = NULL;
1314         }
1315
1316         if (!ws && !set_sign)
1317                 emit_line_0(o, set, NULL, 0, reset, sign, line, len);
1318         else if (!ws) {
1319                 emit_line_0(o, set_sign, set, !!set_sign, reset, sign, line, len);
1320         } else if (blank_at_eof)
1321                 /* Blank line at EOF - paint '+' as well */
1322                 emit_line_0(o, ws, NULL, 0, reset, sign, line, len);
1323         else {
1324                 /* Emit just the prefix, then the rest. */
1325                 emit_line_0(o, set_sign ? set_sign : set, NULL, !!set_sign, reset,
1326                             sign, "", 0);
1327                 ws_check_emit(line, len, ws_rule,
1328                               o->file, set, reset, ws);
1329         }
1330 }
1331
1332 static void emit_diff_symbol_from_struct(struct diff_options *o,
1333                                          struct emitted_diff_symbol *eds)
1334 {
1335         static const char *nneof = " No newline at end of file\n";
1336         const char *context, *reset, *set, *set_sign, *meta, *fraginfo;
1337         struct strbuf sb = STRBUF_INIT;
1338
1339         enum diff_symbol s = eds->s;
1340         const char *line = eds->line;
1341         int len = eds->len;
1342         unsigned flags = eds->flags;
1343
1344         switch (s) {
1345         case DIFF_SYMBOL_NO_LF_EOF:
1346                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1347                 reset = diff_get_color_opt(o, DIFF_RESET);
1348                 putc('\n', o->file);
1349                 emit_line_0(o, context, NULL, 0, reset, '\\',
1350                             nneof, strlen(nneof));
1351                 break;
1352         case DIFF_SYMBOL_SUBMODULE_HEADER:
1353         case DIFF_SYMBOL_SUBMODULE_ERROR:
1354         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1355         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1356         case DIFF_SYMBOL_SUMMARY:
1357         case DIFF_SYMBOL_STATS_LINE:
1358         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1359         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1360                 emit_line(o, "", "", line, len);
1361                 break;
1362         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1363         case DIFF_SYMBOL_CONTEXT_MARKER:
1364                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1365                 reset = diff_get_color_opt(o, DIFF_RESET);
1366                 emit_line(o, context, reset, line, len);
1367                 break;
1368         case DIFF_SYMBOL_SEPARATOR:
1369                 fprintf(o->file, "%s%c",
1370                         diff_line_prefix(o),
1371                         o->line_termination);
1372                 break;
1373         case DIFF_SYMBOL_CONTEXT:
1374                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1375                 reset = diff_get_color_opt(o, DIFF_RESET);
1376                 set_sign = NULL;
1377                 if (o->flags.dual_color_diffed_diffs) {
1378                         char c = !len ? 0 : line[0];
1379
1380                         if (c == '+')
1381                                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1382                         else if (c == '@')
1383                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1384                         else if (c == '-')
1385                                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1386                 }
1387                 emit_line_ws_markup(o, set_sign, set, reset,
1388                                     OUTPUT_INDICATOR_CONTEXT, line, len,
1389                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1390                 break;
1391         case DIFF_SYMBOL_PLUS:
1392                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1393                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1394                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1395                 case DIFF_SYMBOL_MOVED_LINE |
1396                      DIFF_SYMBOL_MOVED_LINE_ALT |
1397                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1398                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1399                         break;
1400                 case DIFF_SYMBOL_MOVED_LINE |
1401                      DIFF_SYMBOL_MOVED_LINE_ALT:
1402                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1403                         break;
1404                 case DIFF_SYMBOL_MOVED_LINE |
1405                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1406                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1407                         break;
1408                 case DIFF_SYMBOL_MOVED_LINE:
1409                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1410                         break;
1411                 default:
1412                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1413                 }
1414                 reset = diff_get_color_opt(o, DIFF_RESET);
1415                 if (!o->flags.dual_color_diffed_diffs)
1416                         set_sign = NULL;
1417                 else {
1418                         char c = !len ? 0 : line[0];
1419
1420                         set_sign = set;
1421                         if (c == '-')
1422                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_BOLD);
1423                         else if (c == '@')
1424                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1425                         else if (c == '+')
1426                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_BOLD);
1427                         else
1428                                 set = diff_get_color_opt(o, DIFF_CONTEXT_BOLD);
1429                         flags &= ~DIFF_SYMBOL_CONTENT_WS_MASK;
1430                 }
1431                 emit_line_ws_markup(o, set_sign, set, reset,
1432                                     OUTPUT_INDICATOR_NEW, line, len,
1433                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1434                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1435                 break;
1436         case DIFF_SYMBOL_MINUS:
1437                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1438                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1439                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1440                 case DIFF_SYMBOL_MOVED_LINE |
1441                      DIFF_SYMBOL_MOVED_LINE_ALT |
1442                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1443                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1444                         break;
1445                 case DIFF_SYMBOL_MOVED_LINE |
1446                      DIFF_SYMBOL_MOVED_LINE_ALT:
1447                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1448                         break;
1449                 case DIFF_SYMBOL_MOVED_LINE |
1450                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1451                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1452                         break;
1453                 case DIFF_SYMBOL_MOVED_LINE:
1454                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1455                         break;
1456                 default:
1457                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1458                 }
1459                 reset = diff_get_color_opt(o, DIFF_RESET);
1460                 if (!o->flags.dual_color_diffed_diffs)
1461                         set_sign = NULL;
1462                 else {
1463                         char c = !len ? 0 : line[0];
1464
1465                         set_sign = set;
1466                         if (c == '+')
1467                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_DIM);
1468                         else if (c == '@')
1469                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1470                         else if (c == '-')
1471                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_DIM);
1472                         else
1473                                 set = diff_get_color_opt(o, DIFF_CONTEXT_DIM);
1474                 }
1475                 emit_line_ws_markup(o, set_sign, set, reset,
1476                                     OUTPUT_INDICATOR_OLD, line, len,
1477                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1478                 break;
1479         case DIFF_SYMBOL_WORDS_PORCELAIN:
1480                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1481                 reset = diff_get_color_opt(o, DIFF_RESET);
1482                 emit_line(o, context, reset, line, len);
1483                 fputs("~\n", o->file);
1484                 break;
1485         case DIFF_SYMBOL_WORDS:
1486                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1487                 reset = diff_get_color_opt(o, DIFF_RESET);
1488                 /*
1489                  * Skip the prefix character, if any.  With
1490                  * diff_suppress_blank_empty, there may be
1491                  * none.
1492                  */
1493                 if (line[0] != '\n') {
1494                         line++;
1495                         len--;
1496                 }
1497                 emit_line(o, context, reset, line, len);
1498                 break;
1499         case DIFF_SYMBOL_FILEPAIR_PLUS:
1500                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1501                 reset = diff_get_color_opt(o, DIFF_RESET);
1502                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1503                         line, reset,
1504                         strchr(line, ' ') ? "\t" : "");
1505                 break;
1506         case DIFF_SYMBOL_FILEPAIR_MINUS:
1507                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1508                 reset = diff_get_color_opt(o, DIFF_RESET);
1509                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1510                         line, reset,
1511                         strchr(line, ' ') ? "\t" : "");
1512                 break;
1513         case DIFF_SYMBOL_BINARY_FILES:
1514         case DIFF_SYMBOL_HEADER:
1515                 fprintf(o->file, "%s", line);
1516                 break;
1517         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1518                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1519                 break;
1520         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1521                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1522                 break;
1523         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1524                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1525                 break;
1526         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1527                 fputs(diff_line_prefix(o), o->file);
1528                 fputc('\n', o->file);
1529                 break;
1530         case DIFF_SYMBOL_REWRITE_DIFF:
1531                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1532                 reset = diff_get_color_opt(o, DIFF_RESET);
1533                 emit_line(o, fraginfo, reset, line, len);
1534                 break;
1535         case DIFF_SYMBOL_SUBMODULE_ADD:
1536                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1537                 reset = diff_get_color_opt(o, DIFF_RESET);
1538                 emit_line(o, set, reset, line, len);
1539                 break;
1540         case DIFF_SYMBOL_SUBMODULE_DEL:
1541                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1542                 reset = diff_get_color_opt(o, DIFF_RESET);
1543                 emit_line(o, set, reset, line, len);
1544                 break;
1545         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1546                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1547                         diff_line_prefix(o), line);
1548                 break;
1549         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1550                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1551                         diff_line_prefix(o), line);
1552                 break;
1553         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1554                 emit_line(o, "", "", " 0 files changed\n",
1555                           strlen(" 0 files changed\n"));
1556                 break;
1557         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1558                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1559                 break;
1560         case DIFF_SYMBOL_WORD_DIFF:
1561                 fprintf(o->file, "%.*s", len, line);
1562                 break;
1563         case DIFF_SYMBOL_STAT_SEP:
1564                 fputs(o->stat_sep, o->file);
1565                 break;
1566         default:
1567                 BUG("unknown diff symbol");
1568         }
1569         strbuf_release(&sb);
1570 }
1571
1572 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1573                              const char *line, int len, unsigned flags)
1574 {
1575         struct emitted_diff_symbol e = {line, len, flags, 0, 0, s};
1576
1577         if (o->emitted_symbols)
1578                 append_emitted_diff_symbol(o, &e);
1579         else
1580                 emit_diff_symbol_from_struct(o, &e);
1581 }
1582
1583 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1584 {
1585         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1586 }
1587
1588 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1589 {
1590         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1591 }
1592
1593 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1594 {
1595         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1596                          path, strlen(path), 0);
1597 }
1598
1599 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1600 {
1601         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1602                          path, strlen(path), 0);
1603 }
1604
1605 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1606 {
1607         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1608                          header, strlen(header), 0);
1609 }
1610
1611 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1612 {
1613         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1614 }
1615
1616 void diff_emit_submodule_pipethrough(struct diff_options *o,
1617                                      const char *line, int len)
1618 {
1619         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1620 }
1621
1622 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1623 {
1624         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1625               ecbdata->blank_at_eof_in_preimage &&
1626               ecbdata->blank_at_eof_in_postimage &&
1627               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1628               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1629                 return 0;
1630         return ws_blank_line(line, len, ecbdata->ws_rule);
1631 }
1632
1633 static void emit_add_line(struct emit_callback *ecbdata,
1634                           const char *line, int len)
1635 {
1636         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1637         if (new_blank_line_at_eof(ecbdata, line, len))
1638                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1639
1640         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1641 }
1642
1643 static void emit_del_line(struct emit_callback *ecbdata,
1644                           const char *line, int len)
1645 {
1646         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1647         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1648 }
1649
1650 static void emit_context_line(struct emit_callback *ecbdata,
1651                               const char *line, int len)
1652 {
1653         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1654         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1655 }
1656
1657 static void emit_hunk_header(struct emit_callback *ecbdata,
1658                              const char *line, int len)
1659 {
1660         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1661         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1662         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1663         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1664         const char *reverse = ecbdata->color_diff ? GIT_COLOR_REVERSE : "";
1665         static const char atat[2] = { '@', '@' };
1666         const char *cp, *ep;
1667         struct strbuf msgbuf = STRBUF_INIT;
1668         int org_len = len;
1669         int i = 1;
1670
1671         /*
1672          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1673          * it always is at least 10 bytes long.
1674          */
1675         if (len < 10 ||
1676             memcmp(line, atat, 2) ||
1677             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1678                 emit_diff_symbol(ecbdata->opt,
1679                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1680                 return;
1681         }
1682         ep += 2; /* skip over @@ */
1683
1684         /* The hunk header in fraginfo color */
1685         if (ecbdata->opt->flags.dual_color_diffed_diffs)
1686                 strbuf_addstr(&msgbuf, reverse);
1687         strbuf_addstr(&msgbuf, frag);
1688         if (ecbdata->opt->flags.suppress_hunk_header_line_count)
1689                 strbuf_add(&msgbuf, atat, sizeof(atat));
1690         else
1691                 strbuf_add(&msgbuf, line, ep - line);
1692         strbuf_addstr(&msgbuf, reset);
1693
1694         /*
1695          * trailing "\r\n"
1696          */
1697         for ( ; i < 3; i++)
1698                 if (line[len - i] == '\r' || line[len - i] == '\n')
1699                         len--;
1700
1701         /* blank before the func header */
1702         for (cp = ep; ep - line < len; ep++)
1703                 if (*ep != ' ' && *ep != '\t')
1704                         break;
1705         if (ep != cp) {
1706                 strbuf_addstr(&msgbuf, context);
1707                 strbuf_add(&msgbuf, cp, ep - cp);
1708                 strbuf_addstr(&msgbuf, reset);
1709         }
1710
1711         if (ep < line + len) {
1712                 strbuf_addstr(&msgbuf, func);
1713                 strbuf_add(&msgbuf, ep, line + len - ep);
1714                 strbuf_addstr(&msgbuf, reset);
1715         }
1716
1717         strbuf_add(&msgbuf, line + len, org_len - len);
1718         strbuf_complete_line(&msgbuf);
1719         emit_diff_symbol(ecbdata->opt,
1720                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1721         strbuf_release(&msgbuf);
1722 }
1723
1724 static struct diff_tempfile *claim_diff_tempfile(void)
1725 {
1726         int i;
1727         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1728                 if (!diff_temp[i].name)
1729                         return diff_temp + i;
1730         BUG("diff is failing to clean up its tempfiles");
1731 }
1732
1733 static void remove_tempfile(void)
1734 {
1735         int i;
1736         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1737                 if (is_tempfile_active(diff_temp[i].tempfile))
1738                         delete_tempfile(&diff_temp[i].tempfile);
1739                 diff_temp[i].name = NULL;
1740         }
1741 }
1742
1743 static void add_line_count(struct strbuf *out, int count)
1744 {
1745         switch (count) {
1746         case 0:
1747                 strbuf_addstr(out, "0,0");
1748                 break;
1749         case 1:
1750                 strbuf_addstr(out, "1");
1751                 break;
1752         default:
1753                 strbuf_addf(out, "1,%d", count);
1754                 break;
1755         }
1756 }
1757
1758 static void emit_rewrite_lines(struct emit_callback *ecb,
1759                                int prefix, const char *data, int size)
1760 {
1761         const char *endp = NULL;
1762
1763         while (0 < size) {
1764                 int len;
1765
1766                 endp = memchr(data, '\n', size);
1767                 len = endp ? (endp - data + 1) : size;
1768                 if (prefix != '+') {
1769                         ecb->lno_in_preimage++;
1770                         emit_del_line(ecb, data, len);
1771                 } else {
1772                         ecb->lno_in_postimage++;
1773                         emit_add_line(ecb, data, len);
1774                 }
1775                 size -= len;
1776                 data += len;
1777         }
1778         if (!endp)
1779                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1780 }
1781
1782 static void emit_rewrite_diff(const char *name_a,
1783                               const char *name_b,
1784                               struct diff_filespec *one,
1785                               struct diff_filespec *two,
1786                               struct userdiff_driver *textconv_one,
1787                               struct userdiff_driver *textconv_two,
1788                               struct diff_options *o)
1789 {
1790         int lc_a, lc_b;
1791         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1792         const char *a_prefix, *b_prefix;
1793         char *data_one, *data_two;
1794         size_t size_one, size_two;
1795         struct emit_callback ecbdata;
1796         struct strbuf out = STRBUF_INIT;
1797
1798         if (diff_mnemonic_prefix && o->flags.reverse_diff) {
1799                 a_prefix = o->b_prefix;
1800                 b_prefix = o->a_prefix;
1801         } else {
1802                 a_prefix = o->a_prefix;
1803                 b_prefix = o->b_prefix;
1804         }
1805
1806         name_a += (*name_a == '/');
1807         name_b += (*name_b == '/');
1808
1809         strbuf_reset(&a_name);
1810         strbuf_reset(&b_name);
1811         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1812         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1813
1814         size_one = fill_textconv(o->repo, textconv_one, one, &data_one);
1815         size_two = fill_textconv(o->repo, textconv_two, two, &data_two);
1816
1817         memset(&ecbdata, 0, sizeof(ecbdata));
1818         ecbdata.color_diff = want_color(o->use_color);
1819         ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
1820         ecbdata.opt = o;
1821         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1822                 mmfile_t mf1, mf2;
1823                 mf1.ptr = (char *)data_one;
1824                 mf2.ptr = (char *)data_two;
1825                 mf1.size = size_one;
1826                 mf2.size = size_two;
1827                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1828         }
1829         ecbdata.lno_in_preimage = 1;
1830         ecbdata.lno_in_postimage = 1;
1831
1832         lc_a = count_lines(data_one, size_one);
1833         lc_b = count_lines(data_two, size_two);
1834
1835         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1836                          a_name.buf, a_name.len, 0);
1837         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1838                          b_name.buf, b_name.len, 0);
1839
1840         strbuf_addstr(&out, "@@ -");
1841         if (!o->irreversible_delete)
1842                 add_line_count(&out, lc_a);
1843         else
1844                 strbuf_addstr(&out, "?,?");
1845         strbuf_addstr(&out, " +");
1846         add_line_count(&out, lc_b);
1847         strbuf_addstr(&out, " @@\n");
1848         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1849         strbuf_release(&out);
1850
1851         if (lc_a && !o->irreversible_delete)
1852                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1853         if (lc_b)
1854                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1855         if (textconv_one)
1856                 free((char *)data_one);
1857         if (textconv_two)
1858                 free((char *)data_two);
1859 }
1860
1861 struct diff_words_buffer {
1862         mmfile_t text;
1863         unsigned long alloc;
1864         struct diff_words_orig {
1865                 const char *begin, *end;
1866         } *orig;
1867         int orig_nr, orig_alloc;
1868 };
1869
1870 static void diff_words_append(char *line, unsigned long len,
1871                 struct diff_words_buffer *buffer)
1872 {
1873         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1874         line++;
1875         len--;
1876         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1877         buffer->text.size += len;
1878         buffer->text.ptr[buffer->text.size] = '\0';
1879 }
1880
1881 struct diff_words_style_elem {
1882         const char *prefix;
1883         const char *suffix;
1884         const char *color; /* NULL; filled in by the setup code if
1885                             * color is enabled */
1886 };
1887
1888 struct diff_words_style {
1889         enum diff_words_type type;
1890         struct diff_words_style_elem new_word, old_word, ctx;
1891         const char *newline;
1892 };
1893
1894 static struct diff_words_style diff_words_styles[] = {
1895         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1896         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1897         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1898 };
1899
1900 struct diff_words_data {
1901         struct diff_words_buffer minus, plus;
1902         const char *current_plus;
1903         int last_minus;
1904         struct diff_options *opt;
1905         regex_t *word_regex;
1906         enum diff_words_type type;
1907         struct diff_words_style *style;
1908 };
1909
1910 static int fn_out_diff_words_write_helper(struct diff_options *o,
1911                                           struct diff_words_style_elem *st_el,
1912                                           const char *newline,
1913                                           size_t count, const char *buf)
1914 {
1915         int print = 0;
1916         struct strbuf sb = STRBUF_INIT;
1917
1918         while (count) {
1919                 char *p = memchr(buf, '\n', count);
1920                 if (print)
1921                         strbuf_addstr(&sb, diff_line_prefix(o));
1922
1923                 if (p != buf) {
1924                         const char *reset = st_el->color && *st_el->color ?
1925                                             GIT_COLOR_RESET : NULL;
1926                         if (st_el->color && *st_el->color)
1927                                 strbuf_addstr(&sb, st_el->color);
1928                         strbuf_addstr(&sb, st_el->prefix);
1929                         strbuf_add(&sb, buf, p ? p - buf : count);
1930                         strbuf_addstr(&sb, st_el->suffix);
1931                         if (reset)
1932                                 strbuf_addstr(&sb, reset);
1933                 }
1934                 if (!p)
1935                         goto out;
1936
1937                 strbuf_addstr(&sb, newline);
1938                 count -= p + 1 - buf;
1939                 buf = p + 1;
1940                 print = 1;
1941                 if (count) {
1942                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1943                                          sb.buf, sb.len, 0);
1944                         strbuf_reset(&sb);
1945                 }
1946         }
1947
1948 out:
1949         if (sb.len)
1950                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1951                                  sb.buf, sb.len, 0);
1952         strbuf_release(&sb);
1953         return 0;
1954 }
1955
1956 /*
1957  * '--color-words' algorithm can be described as:
1958  *
1959  *   1. collect the minus/plus lines of a diff hunk, divided into
1960  *      minus-lines and plus-lines;
1961  *
1962  *   2. break both minus-lines and plus-lines into words and
1963  *      place them into two mmfile_t with one word for each line;
1964  *
1965  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1966  *
1967  * And for the common parts of the both file, we output the plus side text.
1968  * diff_words->current_plus is used to trace the current position of the plus file
1969  * which printed. diff_words->last_minus is used to trace the last minus word
1970  * printed.
1971  *
1972  * For '--graph' to work with '--color-words', we need to output the graph prefix
1973  * on each line of color words output. Generally, there are two conditions on
1974  * which we should output the prefix.
1975  *
1976  *   1. diff_words->last_minus == 0 &&
1977  *      diff_words->current_plus == diff_words->plus.text.ptr
1978  *
1979  *      that is: the plus text must start as a new line, and if there is no minus
1980  *      word printed, a graph prefix must be printed.
1981  *
1982  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1983  *      *(diff_words->current_plus - 1) == '\n'
1984  *
1985  *      that is: a graph prefix must be printed following a '\n'
1986  */
1987 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1988 {
1989         if ((diff_words->last_minus == 0 &&
1990                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1991                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1992                 *(diff_words->current_plus - 1) == '\n')) {
1993                 return 1;
1994         } else {
1995                 return 0;
1996         }
1997 }
1998
1999 static void fn_out_diff_words_aux(void *priv,
2000                                   long minus_first, long minus_len,
2001                                   long plus_first, long plus_len,
2002                                   const char *func, long funclen)
2003 {
2004         struct diff_words_data *diff_words = priv;
2005         struct diff_words_style *style = diff_words->style;
2006         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
2007         struct diff_options *opt = diff_words->opt;
2008         const char *line_prefix;
2009
2010         assert(opt);
2011         line_prefix = diff_line_prefix(opt);
2012
2013         /* POSIX requires that first be decremented by one if len == 0... */
2014         if (minus_len) {
2015                 minus_begin = diff_words->minus.orig[minus_first].begin;
2016                 minus_end =
2017                         diff_words->minus.orig[minus_first + minus_len - 1].end;
2018         } else
2019                 minus_begin = minus_end =
2020                         diff_words->minus.orig[minus_first].end;
2021
2022         if (plus_len) {
2023                 plus_begin = diff_words->plus.orig[plus_first].begin;
2024                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
2025         } else
2026                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
2027
2028         if (color_words_output_graph_prefix(diff_words)) {
2029                 fputs(line_prefix, diff_words->opt->file);
2030         }
2031         if (diff_words->current_plus != plus_begin) {
2032                 fn_out_diff_words_write_helper(diff_words->opt,
2033                                 &style->ctx, style->newline,
2034                                 plus_begin - diff_words->current_plus,
2035                                 diff_words->current_plus);
2036         }
2037         if (minus_begin != minus_end) {
2038                 fn_out_diff_words_write_helper(diff_words->opt,
2039                                 &style->old_word, style->newline,
2040                                 minus_end - minus_begin, minus_begin);
2041         }
2042         if (plus_begin != plus_end) {
2043                 fn_out_diff_words_write_helper(diff_words->opt,
2044                                 &style->new_word, style->newline,
2045                                 plus_end - plus_begin, plus_begin);
2046         }
2047
2048         diff_words->current_plus = plus_end;
2049         diff_words->last_minus = minus_first;
2050 }
2051
2052 /* This function starts looking at *begin, and returns 0 iff a word was found. */
2053 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
2054                 int *begin, int *end)
2055 {
2056         if (word_regex && *begin < buffer->size) {
2057                 regmatch_t match[1];
2058                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
2059                                  buffer->size - *begin, 1, match, 0)) {
2060                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
2061                                         '\n', match[0].rm_eo - match[0].rm_so);
2062                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
2063                         *begin += match[0].rm_so;
2064                         return *begin >= *end;
2065                 }
2066                 return -1;
2067         }
2068
2069         /* find the next word */
2070         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
2071                 (*begin)++;
2072         if (*begin >= buffer->size)
2073                 return -1;
2074
2075         /* find the end of the word */
2076         *end = *begin + 1;
2077         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
2078                 (*end)++;
2079
2080         return 0;
2081 }
2082
2083 /*
2084  * This function splits the words in buffer->text, stores the list with
2085  * newline separator into out, and saves the offsets of the original words
2086  * in buffer->orig.
2087  */
2088 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
2089                 regex_t *word_regex)
2090 {
2091         int i, j;
2092         long alloc = 0;
2093
2094         out->size = 0;
2095         out->ptr = NULL;
2096
2097         /* fake an empty "0th" word */
2098         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
2099         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
2100         buffer->orig_nr = 1;
2101
2102         for (i = 0; i < buffer->text.size; i++) {
2103                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
2104                         return;
2105
2106                 /* store original boundaries */
2107                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
2108                                 buffer->orig_alloc);
2109                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
2110                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
2111                 buffer->orig_nr++;
2112
2113                 /* store one word */
2114                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
2115                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
2116                 out->ptr[out->size + j - i] = '\n';
2117                 out->size += j - i + 1;
2118
2119                 i = j - 1;
2120         }
2121 }
2122
2123 /* this executes the word diff on the accumulated buffers */
2124 static void diff_words_show(struct diff_words_data *diff_words)
2125 {
2126         xpparam_t xpp;
2127         xdemitconf_t xecfg;
2128         mmfile_t minus, plus;
2129         struct diff_words_style *style = diff_words->style;
2130
2131         struct diff_options *opt = diff_words->opt;
2132         const char *line_prefix;
2133
2134         assert(opt);
2135         line_prefix = diff_line_prefix(opt);
2136
2137         /* special case: only removal */
2138         if (!diff_words->plus.text.size) {
2139                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2140                                  line_prefix, strlen(line_prefix), 0);
2141                 fn_out_diff_words_write_helper(diff_words->opt,
2142                         &style->old_word, style->newline,
2143                         diff_words->minus.text.size,
2144                         diff_words->minus.text.ptr);
2145                 diff_words->minus.text.size = 0;
2146                 return;
2147         }
2148
2149         diff_words->current_plus = diff_words->plus.text.ptr;
2150         diff_words->last_minus = 0;
2151
2152         memset(&xpp, 0, sizeof(xpp));
2153         memset(&xecfg, 0, sizeof(xecfg));
2154         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
2155         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
2156         xpp.flags = 0;
2157         /* as only the hunk header will be parsed, we need a 0-context */
2158         xecfg.ctxlen = 0;
2159         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, NULL,
2160                           diff_words, &xpp, &xecfg))
2161                 die("unable to generate word diff");
2162         free(minus.ptr);
2163         free(plus.ptr);
2164         if (diff_words->current_plus != diff_words->plus.text.ptr +
2165                         diff_words->plus.text.size) {
2166                 if (color_words_output_graph_prefix(diff_words))
2167                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2168                                          line_prefix, strlen(line_prefix), 0);
2169                 fn_out_diff_words_write_helper(diff_words->opt,
2170                         &style->ctx, style->newline,
2171                         diff_words->plus.text.ptr + diff_words->plus.text.size
2172                         - diff_words->current_plus, diff_words->current_plus);
2173         }
2174         diff_words->minus.text.size = diff_words->plus.text.size = 0;
2175 }
2176
2177 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
2178 static void diff_words_flush(struct emit_callback *ecbdata)
2179 {
2180         struct diff_options *wo = ecbdata->diff_words->opt;
2181
2182         if (ecbdata->diff_words->minus.text.size ||
2183             ecbdata->diff_words->plus.text.size)
2184                 diff_words_show(ecbdata->diff_words);
2185
2186         if (wo->emitted_symbols) {
2187                 struct diff_options *o = ecbdata->opt;
2188                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
2189                 int i;
2190
2191                 /*
2192                  * NEEDSWORK:
2193                  * Instead of appending each, concat all words to a line?
2194                  */
2195                 for (i = 0; i < wol->nr; i++)
2196                         append_emitted_diff_symbol(o, &wol->buf[i]);
2197
2198                 for (i = 0; i < wol->nr; i++)
2199                         free((void *)wol->buf[i].line);
2200
2201                 wol->nr = 0;
2202         }
2203 }
2204
2205 static void diff_filespec_load_driver(struct diff_filespec *one,
2206                                       struct index_state *istate)
2207 {
2208         /* Use already-loaded driver */
2209         if (one->driver)
2210                 return;
2211
2212         if (S_ISREG(one->mode))
2213                 one->driver = userdiff_find_by_path(istate, one->path);
2214
2215         /* Fallback to default settings */
2216         if (!one->driver)
2217                 one->driver = userdiff_find_by_name("default");
2218 }
2219
2220 static const char *userdiff_word_regex(struct diff_filespec *one,
2221                                        struct index_state *istate)
2222 {
2223         diff_filespec_load_driver(one, istate);
2224         return one->driver->word_regex;
2225 }
2226
2227 static void init_diff_words_data(struct emit_callback *ecbdata,
2228                                  struct diff_options *orig_opts,
2229                                  struct diff_filespec *one,
2230                                  struct diff_filespec *two)
2231 {
2232         int i;
2233         struct diff_options *o = xmalloc(sizeof(struct diff_options));
2234         memcpy(o, orig_opts, sizeof(struct diff_options));
2235
2236         ecbdata->diff_words =
2237                 xcalloc(1, sizeof(struct diff_words_data));
2238         ecbdata->diff_words->type = o->word_diff;
2239         ecbdata->diff_words->opt = o;
2240
2241         if (orig_opts->emitted_symbols)
2242                 o->emitted_symbols =
2243                         xcalloc(1, sizeof(struct emitted_diff_symbols));
2244
2245         if (!o->word_regex)
2246                 o->word_regex = userdiff_word_regex(one, o->repo->index);
2247         if (!o->word_regex)
2248                 o->word_regex = userdiff_word_regex(two, o->repo->index);
2249         if (!o->word_regex)
2250                 o->word_regex = diff_word_regex_cfg;
2251         if (o->word_regex) {
2252                 ecbdata->diff_words->word_regex = (regex_t *)
2253                         xmalloc(sizeof(regex_t));
2254                 if (regcomp(ecbdata->diff_words->word_regex,
2255                             o->word_regex,
2256                             REG_EXTENDED | REG_NEWLINE))
2257                         die("invalid regular expression: %s",
2258                             o->word_regex);
2259         }
2260         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2261                 if (o->word_diff == diff_words_styles[i].type) {
2262                         ecbdata->diff_words->style =
2263                                 &diff_words_styles[i];
2264                         break;
2265                 }
2266         }
2267         if (want_color(o->use_color)) {
2268                 struct diff_words_style *st = ecbdata->diff_words->style;
2269                 st->old_word.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2270                 st->new_word.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2271                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
2272         }
2273 }
2274
2275 static void free_diff_words_data(struct emit_callback *ecbdata)
2276 {
2277         if (ecbdata->diff_words) {
2278                 diff_words_flush(ecbdata);
2279                 free (ecbdata->diff_words->opt->emitted_symbols);
2280                 free (ecbdata->diff_words->opt);
2281                 free (ecbdata->diff_words->minus.text.ptr);
2282                 free (ecbdata->diff_words->minus.orig);
2283                 free (ecbdata->diff_words->plus.text.ptr);
2284                 free (ecbdata->diff_words->plus.orig);
2285                 if (ecbdata->diff_words->word_regex) {
2286                         regfree(ecbdata->diff_words->word_regex);
2287                         free(ecbdata->diff_words->word_regex);
2288                 }
2289                 FREE_AND_NULL(ecbdata->diff_words);
2290         }
2291 }
2292
2293 const char *diff_get_color(int diff_use_color, enum color_diff ix)
2294 {
2295         if (want_color(diff_use_color))
2296                 return diff_colors[ix];
2297         return "";
2298 }
2299
2300 const char *diff_line_prefix(struct diff_options *opt)
2301 {
2302         struct strbuf *msgbuf;
2303         if (!opt->output_prefix)
2304                 return "";
2305
2306         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
2307         return msgbuf->buf;
2308 }
2309
2310 static unsigned long sane_truncate_line(char *line, unsigned long len)
2311 {
2312         const char *cp;
2313         unsigned long allot;
2314         size_t l = len;
2315
2316         cp = line;
2317         allot = l;
2318         while (0 < l) {
2319                 (void) utf8_width(&cp, &l);
2320                 if (!cp)
2321                         break; /* truncated in the middle? */
2322         }
2323         return allot - l;
2324 }
2325
2326 static void find_lno(const char *line, struct emit_callback *ecbdata)
2327 {
2328         const char *p;
2329         ecbdata->lno_in_preimage = 0;
2330         ecbdata->lno_in_postimage = 0;
2331         p = strchr(line, '-');
2332         if (!p)
2333                 return; /* cannot happen */
2334         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
2335         p = strchr(p, '+');
2336         if (!p)
2337                 return; /* cannot happen */
2338         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
2339 }
2340
2341 static void fn_out_consume(void *priv, char *line, unsigned long len)
2342 {
2343         struct emit_callback *ecbdata = priv;
2344         struct diff_options *o = ecbdata->opt;
2345
2346         o->found_changes = 1;
2347
2348         if (ecbdata->header) {
2349                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2350                                  ecbdata->header->buf, ecbdata->header->len, 0);
2351                 strbuf_reset(ecbdata->header);
2352                 ecbdata->header = NULL;
2353         }
2354
2355         if (ecbdata->label_path[0]) {
2356                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
2357                                  ecbdata->label_path[0],
2358                                  strlen(ecbdata->label_path[0]), 0);
2359                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
2360                                  ecbdata->label_path[1],
2361                                  strlen(ecbdata->label_path[1]), 0);
2362                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
2363         }
2364
2365         if (diff_suppress_blank_empty
2366             && len == 2 && line[0] == ' ' && line[1] == '\n') {
2367                 line[0] = '\n';
2368                 len = 1;
2369         }
2370
2371         if (line[0] == '@') {
2372                 if (ecbdata->diff_words)
2373                         diff_words_flush(ecbdata);
2374                 len = sane_truncate_line(line, len);
2375                 find_lno(line, ecbdata);
2376                 emit_hunk_header(ecbdata, line, len);
2377                 return;
2378         }
2379
2380         if (ecbdata->diff_words) {
2381                 enum diff_symbol s =
2382                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2383                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2384                 if (line[0] == '-') {
2385                         diff_words_append(line, len,
2386                                           &ecbdata->diff_words->minus);
2387                         return;
2388                 } else if (line[0] == '+') {
2389                         diff_words_append(line, len,
2390                                           &ecbdata->diff_words->plus);
2391                         return;
2392                 } else if (starts_with(line, "\\ ")) {
2393                         /*
2394                          * Eat the "no newline at eof" marker as if we
2395                          * saw a "+" or "-" line with nothing on it,
2396                          * and return without diff_words_flush() to
2397                          * defer processing. If this is the end of
2398                          * preimage, more "+" lines may come after it.
2399                          */
2400                         return;
2401                 }
2402                 diff_words_flush(ecbdata);
2403                 emit_diff_symbol(o, s, line, len, 0);
2404                 return;
2405         }
2406
2407         switch (line[0]) {
2408         case '+':
2409                 ecbdata->lno_in_postimage++;
2410                 emit_add_line(ecbdata, line + 1, len - 1);
2411                 break;
2412         case '-':
2413                 ecbdata->lno_in_preimage++;
2414                 emit_del_line(ecbdata, line + 1, len - 1);
2415                 break;
2416         case ' ':
2417                 ecbdata->lno_in_postimage++;
2418                 ecbdata->lno_in_preimage++;
2419                 emit_context_line(ecbdata, line + 1, len - 1);
2420                 break;
2421         default:
2422                 /* incomplete line at the end */
2423                 ecbdata->lno_in_preimage++;
2424                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2425                                  line, len, 0);
2426                 break;
2427         }
2428 }
2429
2430 static void pprint_rename(struct strbuf *name, const char *a, const char *b)
2431 {
2432         const char *old_name = a;
2433         const char *new_name = b;
2434         int pfx_length, sfx_length;
2435         int pfx_adjust_for_slash;
2436         int len_a = strlen(a);
2437         int len_b = strlen(b);
2438         int a_midlen, b_midlen;
2439         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2440         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2441
2442         if (qlen_a || qlen_b) {
2443                 quote_c_style(a, name, NULL, 0);
2444                 strbuf_addstr(name, " => ");
2445                 quote_c_style(b, name, NULL, 0);
2446                 return;
2447         }
2448
2449         /* Find common prefix */
2450         pfx_length = 0;
2451         while (*old_name && *new_name && *old_name == *new_name) {
2452                 if (*old_name == '/')
2453                         pfx_length = old_name - a + 1;
2454                 old_name++;
2455                 new_name++;
2456         }
2457
2458         /* Find common suffix */
2459         old_name = a + len_a;
2460         new_name = b + len_b;
2461         sfx_length = 0;
2462         /*
2463          * If there is a common prefix, it must end in a slash.  In
2464          * that case we let this loop run 1 into the prefix to see the
2465          * same slash.
2466          *
2467          * If there is no common prefix, we cannot do this as it would
2468          * underrun the input strings.
2469          */
2470         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2471         while (a + pfx_length - pfx_adjust_for_slash <= old_name &&
2472                b + pfx_length - pfx_adjust_for_slash <= new_name &&
2473                *old_name == *new_name) {
2474                 if (*old_name == '/')
2475                         sfx_length = len_a - (old_name - a);
2476                 old_name--;
2477                 new_name--;
2478         }
2479
2480         /*
2481          * pfx{mid-a => mid-b}sfx
2482          * {pfx-a => pfx-b}sfx
2483          * pfx{sfx-a => sfx-b}
2484          * name-a => name-b
2485          */
2486         a_midlen = len_a - pfx_length - sfx_length;
2487         b_midlen = len_b - pfx_length - sfx_length;
2488         if (a_midlen < 0)
2489                 a_midlen = 0;
2490         if (b_midlen < 0)
2491                 b_midlen = 0;
2492
2493         strbuf_grow(name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2494         if (pfx_length + sfx_length) {
2495                 strbuf_add(name, a, pfx_length);
2496                 strbuf_addch(name, '{');
2497         }
2498         strbuf_add(name, a + pfx_length, a_midlen);
2499         strbuf_addstr(name, " => ");
2500         strbuf_add(name, b + pfx_length, b_midlen);
2501         if (pfx_length + sfx_length) {
2502                 strbuf_addch(name, '}');
2503                 strbuf_add(name, a + len_a - sfx_length, sfx_length);
2504         }
2505 }
2506
2507 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2508                                           const char *name_a,
2509                                           const char *name_b)
2510 {
2511         struct diffstat_file *x;
2512         x = xcalloc(1, sizeof(*x));
2513         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2514         diffstat->files[diffstat->nr++] = x;
2515         if (name_b) {
2516                 x->from_name = xstrdup(name_a);
2517                 x->name = xstrdup(name_b);
2518                 x->is_renamed = 1;
2519         }
2520         else {
2521                 x->from_name = NULL;
2522                 x->name = xstrdup(name_a);
2523         }
2524         return x;
2525 }
2526
2527 static void diffstat_consume(void *priv, char *line, unsigned long len)
2528 {
2529         struct diffstat_t *diffstat = priv;
2530         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2531
2532         if (line[0] == '+')
2533                 x->added++;
2534         else if (line[0] == '-')
2535                 x->deleted++;
2536 }
2537
2538 const char mime_boundary_leader[] = "------------";
2539
2540 static int scale_linear(int it, int width, int max_change)
2541 {
2542         if (!it)
2543                 return 0;
2544         /*
2545          * make sure that at least one '-' or '+' is printed if
2546          * there is any change to this path. The easiest way is to
2547          * scale linearly as if the allotted width is one column shorter
2548          * than it is, and then add 1 to the result.
2549          */
2550         return 1 + (it * (width - 1) / max_change);
2551 }
2552
2553 static void show_graph(struct strbuf *out, char ch, int cnt,
2554                        const char *set, const char *reset)
2555 {
2556         if (cnt <= 0)
2557                 return;
2558         strbuf_addstr(out, set);
2559         strbuf_addchars(out, ch, cnt);
2560         strbuf_addstr(out, reset);
2561 }
2562
2563 static void fill_print_name(struct diffstat_file *file)
2564 {
2565         struct strbuf pname = STRBUF_INIT;
2566
2567         if (file->print_name)
2568                 return;
2569
2570         if (file->is_renamed)
2571                 pprint_rename(&pname, file->from_name, file->name);
2572         else
2573                 quote_c_style(file->name, &pname, NULL, 0);
2574
2575         if (file->comments)
2576                 strbuf_addf(&pname, " (%s)", file->comments);
2577
2578         file->print_name = strbuf_detach(&pname, NULL);
2579 }
2580
2581 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2582                 int files, int insertions, int deletions)
2583 {
2584         struct strbuf sb = STRBUF_INIT;
2585
2586         if (!files) {
2587                 assert(insertions == 0 && deletions == 0);
2588                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2589                                  NULL, 0, 0);
2590                 return;
2591         }
2592
2593         strbuf_addf(&sb,
2594                     (files == 1) ? " %d file changed" : " %d files changed",
2595                     files);
2596
2597         /*
2598          * For binary diff, the caller may want to print "x files
2599          * changed" with insertions == 0 && deletions == 0.
2600          *
2601          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2602          * is probably less confusing (i.e skip over "2 files changed
2603          * but nothing about added/removed lines? Is this a bug in Git?").
2604          */
2605         if (insertions || deletions == 0) {
2606                 strbuf_addf(&sb,
2607                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2608                             insertions);
2609         }
2610
2611         if (deletions || insertions == 0) {
2612                 strbuf_addf(&sb,
2613                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2614                             deletions);
2615         }
2616         strbuf_addch(&sb, '\n');
2617         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2618                          sb.buf, sb.len, 0);
2619         strbuf_release(&sb);
2620 }
2621
2622 void print_stat_summary(FILE *fp, int files,
2623                         int insertions, int deletions)
2624 {
2625         struct diff_options o;
2626         memset(&o, 0, sizeof(o));
2627         o.file = fp;
2628
2629         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2630 }
2631
2632 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2633 {
2634         int i, len, add, del, adds = 0, dels = 0;
2635         uintmax_t max_change = 0, max_len = 0;
2636         int total_files = data->nr, count;
2637         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2638         const char *reset, *add_c, *del_c;
2639         int extra_shown = 0;
2640         const char *line_prefix = diff_line_prefix(options);
2641         struct strbuf out = STRBUF_INIT;
2642
2643         if (data->nr == 0)
2644                 return;
2645
2646         count = options->stat_count ? options->stat_count : data->nr;
2647
2648         reset = diff_get_color_opt(options, DIFF_RESET);
2649         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2650         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2651
2652         /*
2653          * Find the longest filename and max number of changes
2654          */
2655         for (i = 0; (i < count) && (i < data->nr); i++) {
2656                 struct diffstat_file *file = data->files[i];
2657                 uintmax_t change = file->added + file->deleted;
2658
2659                 if (!file->is_interesting && (change == 0)) {
2660                         count++; /* not shown == room for one more */
2661                         continue;
2662                 }
2663                 fill_print_name(file);
2664                 len = strlen(file->print_name);
2665                 if (max_len < len)
2666                         max_len = len;
2667
2668                 if (file->is_unmerged) {
2669                         /* "Unmerged" is 8 characters */
2670                         bin_width = bin_width < 8 ? 8 : bin_width;
2671                         continue;
2672                 }
2673                 if (file->is_binary) {
2674                         /* "Bin XXX -> YYY bytes" */
2675                         int w = 14 + decimal_width(file->added)
2676                                 + decimal_width(file->deleted);
2677                         bin_width = bin_width < w ? w : bin_width;
2678                         /* Display change counts aligned with "Bin" */
2679                         number_width = 3;
2680                         continue;
2681                 }
2682
2683                 if (max_change < change)
2684                         max_change = change;
2685         }
2686         count = i; /* where we can stop scanning in data->files[] */
2687
2688         /*
2689          * We have width = stat_width or term_columns() columns total.
2690          * We want a maximum of min(max_len, stat_name_width) for the name part.
2691          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2692          * We also need 1 for " " and 4 + decimal_width(max_change)
2693          * for " | NNNN " and one the empty column at the end, altogether
2694          * 6 + decimal_width(max_change).
2695          *
2696          * If there's not enough space, we will use the smaller of
2697          * stat_name_width (if set) and 5/8*width for the filename,
2698          * and the rest for constant elements + graph part, but no more
2699          * than stat_graph_width for the graph part.
2700          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2701          * for the standard terminal size).
2702          *
2703          * In other words: stat_width limits the maximum width, and
2704          * stat_name_width fixes the maximum width of the filename,
2705          * and is also used to divide available columns if there
2706          * aren't enough.
2707          *
2708          * Binary files are displayed with "Bin XXX -> YYY bytes"
2709          * instead of the change count and graph. This part is treated
2710          * similarly to the graph part, except that it is not
2711          * "scaled". If total width is too small to accommodate the
2712          * guaranteed minimum width of the filename part and the
2713          * separators and this message, this message will "overflow"
2714          * making the line longer than the maximum width.
2715          */
2716
2717         if (options->stat_width == -1)
2718                 width = term_columns() - strlen(line_prefix);
2719         else
2720                 width = options->stat_width ? options->stat_width : 80;
2721         number_width = decimal_width(max_change) > number_width ?
2722                 decimal_width(max_change) : number_width;
2723
2724         if (options->stat_graph_width == -1)
2725                 options->stat_graph_width = diff_stat_graph_width;
2726
2727         /*
2728          * Guarantee 3/8*16==6 for the graph part
2729          * and 5/8*16==10 for the filename part
2730          */
2731         if (width < 16 + 6 + number_width)
2732                 width = 16 + 6 + number_width;
2733
2734         /*
2735          * First assign sizes that are wanted, ignoring available width.
2736          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2737          * starting from "XXX" should fit in graph_width.
2738          */
2739         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2740         if (options->stat_graph_width &&
2741             options->stat_graph_width < graph_width)
2742                 graph_width = options->stat_graph_width;
2743
2744         name_width = (options->stat_name_width > 0 &&
2745                       options->stat_name_width < max_len) ?
2746                 options->stat_name_width : max_len;
2747
2748         /*
2749          * Adjust adjustable widths not to exceed maximum width
2750          */
2751         if (name_width + number_width + 6 + graph_width > width) {
2752                 if (graph_width > width * 3/8 - number_width - 6) {
2753                         graph_width = width * 3/8 - number_width - 6;
2754                         if (graph_width < 6)
2755                                 graph_width = 6;
2756                 }
2757
2758                 if (options->stat_graph_width &&
2759                     graph_width > options->stat_graph_width)
2760                         graph_width = options->stat_graph_width;
2761                 if (name_width > width - number_width - 6 - graph_width)
2762                         name_width = width - number_width - 6 - graph_width;
2763                 else
2764                         graph_width = width - number_width - 6 - name_width;
2765         }
2766
2767         /*
2768          * From here name_width is the width of the name area,
2769          * and graph_width is the width of the graph area.
2770          * max_change is used to scale graph properly.
2771          */
2772         for (i = 0; i < count; i++) {
2773                 const char *prefix = "";
2774                 struct diffstat_file *file = data->files[i];
2775                 char *name = file->print_name;
2776                 uintmax_t added = file->added;
2777                 uintmax_t deleted = file->deleted;
2778                 int name_len;
2779
2780                 if (!file->is_interesting && (added + deleted == 0))
2781                         continue;
2782
2783                 /*
2784                  * "scale" the filename
2785                  */
2786                 len = name_width;
2787                 name_len = strlen(name);
2788                 if (name_width < name_len) {
2789                         char *slash;
2790                         prefix = "...";
2791                         len -= 3;
2792                         name += name_len - len;
2793                         slash = strchr(name, '/');
2794                         if (slash)
2795                                 name = slash;
2796                 }
2797
2798                 if (file->is_binary) {
2799                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2800                         strbuf_addf(&out, " %*s", number_width, "Bin");
2801                         if (!added && !deleted) {
2802                                 strbuf_addch(&out, '\n');
2803                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2804                                                  out.buf, out.len, 0);
2805                                 strbuf_reset(&out);
2806                                 continue;
2807                         }
2808                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2809                                 del_c, deleted, reset);
2810                         strbuf_addstr(&out, " -> ");
2811                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2812                                 add_c, added, reset);
2813                         strbuf_addstr(&out, " bytes\n");
2814                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2815                                          out.buf, out.len, 0);
2816                         strbuf_reset(&out);
2817                         continue;
2818                 }
2819                 else if (file->is_unmerged) {
2820                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2821                         strbuf_addstr(&out, " Unmerged\n");
2822                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2823                                          out.buf, out.len, 0);
2824                         strbuf_reset(&out);
2825                         continue;
2826                 }
2827
2828                 /*
2829                  * scale the add/delete
2830                  */
2831                 add = added;
2832                 del = deleted;
2833
2834                 if (graph_width <= max_change) {
2835                         int total = scale_linear(add + del, graph_width, max_change);
2836                         if (total < 2 && add && del)
2837                                 /* width >= 2 due to the sanity check */
2838                                 total = 2;
2839                         if (add < del) {
2840                                 add = scale_linear(add, graph_width, max_change);
2841                                 del = total - add;
2842                         } else {
2843                                 del = scale_linear(del, graph_width, max_change);
2844                                 add = total - del;
2845                         }
2846                 }
2847                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2848                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2849                         number_width, added + deleted,
2850                         added + deleted ? " " : "");
2851                 show_graph(&out, '+', add, add_c, reset);
2852                 show_graph(&out, '-', del, del_c, reset);
2853                 strbuf_addch(&out, '\n');
2854                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2855                                  out.buf, out.len, 0);
2856                 strbuf_reset(&out);
2857         }
2858
2859         for (i = 0; i < data->nr; i++) {
2860                 struct diffstat_file *file = data->files[i];
2861                 uintmax_t added = file->added;
2862                 uintmax_t deleted = file->deleted;
2863
2864                 if (file->is_unmerged ||
2865                     (!file->is_interesting && (added + deleted == 0))) {
2866                         total_files--;
2867                         continue;
2868                 }
2869
2870                 if (!file->is_binary) {
2871                         adds += added;
2872                         dels += deleted;
2873                 }
2874                 if (i < count)
2875                         continue;
2876                 if (!extra_shown)
2877                         emit_diff_symbol(options,
2878                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2879                                          NULL, 0, 0);
2880                 extra_shown = 1;
2881         }
2882
2883         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2884         strbuf_release(&out);
2885 }
2886
2887 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2888 {
2889         int i, adds = 0, dels = 0, total_files = data->nr;
2890
2891         if (data->nr == 0)
2892                 return;
2893
2894         for (i = 0; i < data->nr; i++) {
2895                 int added = data->files[i]->added;
2896                 int deleted = data->files[i]->deleted;
2897
2898                 if (data->files[i]->is_unmerged ||
2899                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2900                         total_files--;
2901                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2902                         adds += added;
2903                         dels += deleted;
2904                 }
2905         }
2906         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2907 }
2908
2909 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2910 {
2911         int i;
2912
2913         if (data->nr == 0)
2914                 return;
2915
2916         for (i = 0; i < data->nr; i++) {
2917                 struct diffstat_file *file = data->files[i];
2918
2919                 fprintf(options->file, "%s", diff_line_prefix(options));
2920
2921                 if (file->is_binary)
2922                         fprintf(options->file, "-\t-\t");
2923                 else
2924                         fprintf(options->file,
2925                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2926                                 file->added, file->deleted);
2927                 if (options->line_termination) {
2928                         fill_print_name(file);
2929                         if (!file->is_renamed)
2930                                 write_name_quoted(file->name, options->file,
2931                                                   options->line_termination);
2932                         else {
2933                                 fputs(file->print_name, options->file);
2934                                 putc(options->line_termination, options->file);
2935                         }
2936                 } else {
2937                         if (file->is_renamed) {
2938                                 putc('\0', options->file);
2939                                 write_name_quoted(file->from_name, options->file, '\0');
2940                         }
2941                         write_name_quoted(file->name, options->file, '\0');
2942                 }
2943         }
2944 }
2945
2946 struct dirstat_file {
2947         const char *name;
2948         unsigned long changed;
2949 };
2950
2951 struct dirstat_dir {
2952         struct dirstat_file *files;
2953         int alloc, nr, permille, cumulative;
2954 };
2955
2956 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2957                 unsigned long changed, const char *base, int baselen)
2958 {
2959         unsigned long sum_changes = 0;
2960         unsigned int sources = 0;
2961         const char *line_prefix = diff_line_prefix(opt);
2962
2963         while (dir->nr) {
2964                 struct dirstat_file *f = dir->files;
2965                 int namelen = strlen(f->name);
2966                 unsigned long changes;
2967                 char *slash;
2968
2969                 if (namelen < baselen)
2970                         break;
2971                 if (memcmp(f->name, base, baselen))
2972                         break;
2973                 slash = strchr(f->name + baselen, '/');
2974                 if (slash) {
2975                         int newbaselen = slash + 1 - f->name;
2976                         changes = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2977                         sources++;
2978                 } else {
2979                         changes = f->changed;
2980                         dir->files++;
2981                         dir->nr--;
2982                         sources += 2;
2983                 }
2984                 sum_changes += changes;
2985         }
2986
2987         /*
2988          * We don't report dirstat's for
2989          *  - the top level
2990          *  - or cases where everything came from a single directory
2991          *    under this directory (sources == 1).
2992          */
2993         if (baselen && sources != 1) {
2994                 if (sum_changes) {
2995                         int permille = sum_changes * 1000 / changed;
2996                         if (permille >= dir->permille) {
2997                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2998                                         permille / 10, permille % 10, baselen, base);
2999                                 if (!dir->cumulative)
3000                                         return 0;
3001                         }
3002                 }
3003         }
3004         return sum_changes;
3005 }
3006
3007 static int dirstat_compare(const void *_a, const void *_b)
3008 {
3009         const struct dirstat_file *a = _a;
3010         const struct dirstat_file *b = _b;
3011         return strcmp(a->name, b->name);
3012 }
3013
3014 static void show_dirstat(struct diff_options *options)
3015 {
3016         int i;
3017         unsigned long changed;
3018         struct dirstat_dir dir;
3019         struct diff_queue_struct *q = &diff_queued_diff;
3020
3021         dir.files = NULL;
3022         dir.alloc = 0;
3023         dir.nr = 0;
3024         dir.permille = options->dirstat_permille;
3025         dir.cumulative = options->flags.dirstat_cumulative;
3026
3027         changed = 0;
3028         for (i = 0; i < q->nr; i++) {
3029                 struct diff_filepair *p = q->queue[i];
3030                 const char *name;
3031                 unsigned long copied, added, damage;
3032                 struct diff_populate_filespec_options dpf_options = {
3033                         .check_size_only = 1,
3034                 };
3035
3036                 name = p->two->path ? p->two->path : p->one->path;
3037
3038                 if (p->one->oid_valid && p->two->oid_valid &&
3039                     oideq(&p->one->oid, &p->two->oid)) {
3040                         /*
3041                          * The SHA1 has not changed, so pre-/post-content is
3042                          * identical. We can therefore skip looking at the
3043                          * file contents altogether.
3044                          */
3045                         damage = 0;
3046                         goto found_damage;
3047                 }
3048
3049                 if (options->flags.dirstat_by_file) {
3050                         /*
3051                          * In --dirstat-by-file mode, we don't really need to
3052                          * look at the actual file contents at all.
3053                          * The fact that the SHA1 changed is enough for us to
3054                          * add this file to the list of results
3055                          * (with each file contributing equal damage).
3056                          */
3057                         damage = 1;
3058                         goto found_damage;
3059                 }
3060
3061                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
3062                         diff_populate_filespec(options->repo, p->one, NULL);
3063                         diff_populate_filespec(options->repo, p->two, NULL);
3064                         diffcore_count_changes(options->repo,
3065                                                p->one, p->two, NULL, NULL,
3066                                                &copied, &added);
3067                         diff_free_filespec_data(p->one);
3068                         diff_free_filespec_data(p->two);
3069                 } else if (DIFF_FILE_VALID(p->one)) {
3070                         diff_populate_filespec(options->repo, p->one, &dpf_options);
3071                         copied = added = 0;
3072                         diff_free_filespec_data(p->one);
3073                 } else if (DIFF_FILE_VALID(p->two)) {
3074                         diff_populate_filespec(options->repo, p->two, &dpf_options);
3075                         copied = 0;
3076                         added = p->two->size;
3077                         diff_free_filespec_data(p->two);
3078                 } else
3079                         continue;
3080
3081                 /*
3082                  * Original minus copied is the removed material,
3083                  * added is the new material.  They are both damages
3084                  * made to the preimage.
3085                  * If the resulting damage is zero, we know that
3086                  * diffcore_count_changes() considers the two entries to
3087                  * be identical, but since the oid changed, we
3088                  * know that there must have been _some_ kind of change,
3089                  * so we force all entries to have damage > 0.
3090                  */
3091                 damage = (p->one->size - copied) + added;
3092                 if (!damage)
3093                         damage = 1;
3094
3095 found_damage:
3096                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3097                 dir.files[dir.nr].name = name;
3098                 dir.files[dir.nr].changed = damage;
3099                 changed += damage;
3100                 dir.nr++;
3101         }
3102
3103         /* This can happen even with many files, if everything was renames */
3104         if (!changed)
3105                 return;
3106
3107         /* Show all directories with more than x% of the changes */
3108         QSORT(dir.files, dir.nr, dirstat_compare);
3109         gather_dirstat(options, &dir, changed, "", 0);
3110 }
3111
3112 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
3113 {
3114         int i;
3115         unsigned long changed;
3116         struct dirstat_dir dir;
3117
3118         if (data->nr == 0)
3119                 return;
3120
3121         dir.files = NULL;
3122         dir.alloc = 0;
3123         dir.nr = 0;
3124         dir.permille = options->dirstat_permille;
3125         dir.cumulative = options->flags.dirstat_cumulative;
3126
3127         changed = 0;
3128         for (i = 0; i < data->nr; i++) {
3129                 struct diffstat_file *file = data->files[i];
3130                 unsigned long damage = file->added + file->deleted;
3131                 if (file->is_binary)
3132                         /*
3133                          * binary files counts bytes, not lines. Must find some
3134                          * way to normalize binary bytes vs. textual lines.
3135                          * The following heuristic assumes that there are 64
3136                          * bytes per "line".
3137                          * This is stupid and ugly, but very cheap...
3138                          */
3139                         damage = DIV_ROUND_UP(damage, 64);
3140                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3141                 dir.files[dir.nr].name = file->name;
3142                 dir.files[dir.nr].changed = damage;
3143                 changed += damage;
3144                 dir.nr++;
3145         }
3146
3147         /* This can happen even with many files, if everything was renames */
3148         if (!changed)
3149                 return;
3150
3151         /* Show all directories with more than x% of the changes */
3152         QSORT(dir.files, dir.nr, dirstat_compare);
3153         gather_dirstat(options, &dir, changed, "", 0);
3154 }
3155
3156 static void free_diffstat_file(struct diffstat_file *f)
3157 {
3158         free(f->print_name);
3159         free(f->name);
3160         free(f->from_name);
3161         free(f);
3162 }
3163
3164 void free_diffstat_info(struct diffstat_t *diffstat)
3165 {
3166         int i;
3167         for (i = 0; i < diffstat->nr; i++)
3168                 free_diffstat_file(diffstat->files[i]);
3169         free(diffstat->files);
3170 }
3171
3172 struct checkdiff_t {
3173         const char *filename;
3174         int lineno;
3175         int conflict_marker_size;
3176         struct diff_options *o;
3177         unsigned ws_rule;
3178         unsigned status;
3179 };
3180
3181 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
3182 {
3183         char firstchar;
3184         int cnt;
3185
3186         if (len < marker_size + 1)
3187                 return 0;
3188         firstchar = line[0];
3189         switch (firstchar) {
3190         case '=': case '>': case '<': case '|':
3191                 break;
3192         default:
3193                 return 0;
3194         }
3195         for (cnt = 1; cnt < marker_size; cnt++)
3196                 if (line[cnt] != firstchar)
3197                         return 0;
3198         /* line[1] through line[marker_size-1] are same as firstchar */
3199         if (len < marker_size + 1 || !isspace(line[marker_size]))
3200                 return 0;
3201         return 1;
3202 }
3203
3204 static void checkdiff_consume_hunk(void *priv,
3205                                    long ob, long on, long nb, long nn,
3206                                    const char *func, long funclen)
3207
3208 {
3209         struct checkdiff_t *data = priv;
3210         data->lineno = nb - 1;
3211 }
3212
3213 static void checkdiff_consume(void *priv, char *line, unsigned long len)
3214 {
3215         struct checkdiff_t *data = priv;
3216         int marker_size = data->conflict_marker_size;
3217         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
3218         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
3219         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
3220         char *err;
3221         const char *line_prefix;
3222
3223         assert(data->o);
3224         line_prefix = diff_line_prefix(data->o);
3225
3226         if (line[0] == '+') {
3227                 unsigned bad;
3228                 data->lineno++;
3229                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
3230                         data->status |= 1;
3231                         fprintf(data->o->file,
3232                                 "%s%s:%d: leftover conflict marker\n",
3233                                 line_prefix, data->filename, data->lineno);
3234                 }
3235                 bad = ws_check(line + 1, len - 1, data->ws_rule);
3236                 if (!bad)
3237                         return;
3238                 data->status |= bad;
3239                 err = whitespace_error_string(bad);
3240                 fprintf(data->o->file, "%s%s:%d: %s.\n",
3241                         line_prefix, data->filename, data->lineno, err);
3242                 free(err);
3243                 emit_line(data->o, set, reset, line, 1);
3244                 ws_check_emit(line + 1, len - 1, data->ws_rule,
3245                               data->o->file, set, reset, ws);
3246         } else if (line[0] == ' ') {
3247                 data->lineno++;
3248         }
3249 }
3250
3251 static unsigned char *deflate_it(char *data,
3252                                  unsigned long size,
3253                                  unsigned long *result_size)
3254 {
3255         int bound;
3256         unsigned char *deflated;
3257         git_zstream stream;
3258
3259         git_deflate_init(&stream, zlib_compression_level);
3260         bound = git_deflate_bound(&stream, size);
3261         deflated = xmalloc(bound);
3262         stream.next_out = deflated;
3263         stream.avail_out = bound;
3264
3265         stream.next_in = (unsigned char *)data;
3266         stream.avail_in = size;
3267         while (git_deflate(&stream, Z_FINISH) == Z_OK)
3268                 ; /* nothing */
3269         git_deflate_end(&stream);
3270         *result_size = stream.total_out;
3271         return deflated;
3272 }
3273
3274 static void emit_binary_diff_body(struct diff_options *o,
3275                                   mmfile_t *one, mmfile_t *two)
3276 {
3277         void *cp;
3278         void *delta;
3279         void *deflated;
3280         void *data;
3281         unsigned long orig_size;
3282         unsigned long delta_size;
3283         unsigned long deflate_size;
3284         unsigned long data_size;
3285
3286         /* We could do deflated delta, or we could do just deflated two,
3287          * whichever is smaller.
3288          */
3289         delta = NULL;
3290         deflated = deflate_it(two->ptr, two->size, &deflate_size);
3291         if (one->size && two->size) {
3292                 delta = diff_delta(one->ptr, one->size,
3293                                    two->ptr, two->size,
3294                                    &delta_size, deflate_size);
3295                 if (delta) {
3296                         void *to_free = delta;
3297                         orig_size = delta_size;
3298                         delta = deflate_it(delta, delta_size, &delta_size);
3299                         free(to_free);
3300                 }
3301         }
3302
3303         if (delta && delta_size < deflate_size) {
3304                 char *s = xstrfmt("%"PRIuMAX , (uintmax_t)orig_size);
3305                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
3306                                  s, strlen(s), 0);
3307                 free(s);
3308                 free(deflated);
3309                 data = delta;
3310                 data_size = delta_size;
3311         } else {
3312                 char *s = xstrfmt("%lu", two->size);
3313                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
3314                                  s, strlen(s), 0);
3315                 free(s);
3316                 free(delta);
3317                 data = deflated;
3318                 data_size = deflate_size;
3319         }
3320
3321         /* emit data encoded in base85 */
3322         cp = data;
3323         while (data_size) {
3324                 int len;
3325                 int bytes = (52 < data_size) ? 52 : data_size;
3326                 char line[71];
3327                 data_size -= bytes;
3328                 if (bytes <= 26)
3329                         line[0] = bytes + 'A' - 1;
3330                 else
3331                         line[0] = bytes - 26 + 'a' - 1;
3332                 encode_85(line + 1, cp, bytes);
3333                 cp = (char *) cp + bytes;
3334
3335                 len = strlen(line);
3336                 line[len++] = '\n';
3337                 line[len] = '\0';
3338
3339                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
3340                                  line, len, 0);
3341         }
3342         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
3343         free(data);
3344 }
3345
3346 static void emit_binary_diff(struct diff_options *o,
3347                              mmfile_t *one, mmfile_t *two)
3348 {
3349         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
3350         emit_binary_diff_body(o, one, two);
3351         emit_binary_diff_body(o, two, one);
3352 }
3353
3354 int diff_filespec_is_binary(struct repository *r,
3355                             struct diff_filespec *one)
3356 {
3357         struct diff_populate_filespec_options dpf_options = {
3358                 .check_binary = 1,
3359         };
3360
3361         if (one->is_binary == -1) {
3362                 diff_filespec_load_driver(one, r->index);
3363                 if (one->driver->binary != -1)
3364                         one->is_binary = one->driver->binary;
3365                 else {
3366                         if (!one->data && DIFF_FILE_VALID(one))
3367                                 diff_populate_filespec(r, one, &dpf_options);
3368                         if (one->is_binary == -1 && one->data)
3369                                 one->is_binary = buffer_is_binary(one->data,
3370                                                 one->size);
3371                         if (one->is_binary == -1)
3372                                 one->is_binary = 0;
3373                 }
3374         }
3375         return one->is_binary;
3376 }
3377
3378 static const struct userdiff_funcname *
3379 diff_funcname_pattern(struct diff_options *o, struct diff_filespec *one)
3380 {
3381         diff_filespec_load_driver(one, o->repo->index);
3382         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3383 }
3384
3385 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3386 {
3387         if (!options->a_prefix)
3388                 options->a_prefix = a;
3389         if (!options->b_prefix)
3390                 options->b_prefix = b;
3391 }
3392
3393 struct userdiff_driver *get_textconv(struct repository *r,
3394                                      struct diff_filespec *one)
3395 {
3396         if (!DIFF_FILE_VALID(one))
3397                 return NULL;
3398
3399         diff_filespec_load_driver(one, r->index);
3400         return userdiff_get_textconv(r, one->driver);
3401 }
3402
3403 static void builtin_diff(const char *name_a,
3404                          const char *name_b,
3405                          struct diff_filespec *one,
3406                          struct diff_filespec *two,
3407                          const char *xfrm_msg,
3408                          int must_show_header,
3409                          struct diff_options *o,
3410                          int complete_rewrite)
3411 {
3412         mmfile_t mf1, mf2;
3413         const char *lbl[2];
3414         char *a_one, *b_two;
3415         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3416         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3417         const char *a_prefix, *b_prefix;
3418         struct userdiff_driver *textconv_one = NULL;
3419         struct userdiff_driver *textconv_two = NULL;
3420         struct strbuf header = STRBUF_INIT;
3421         const char *line_prefix = diff_line_prefix(o);
3422
3423         diff_set_mnemonic_prefix(o, "a/", "b/");
3424         if (o->flags.reverse_diff) {
3425                 a_prefix = o->b_prefix;
3426                 b_prefix = o->a_prefix;
3427         } else {
3428                 a_prefix = o->a_prefix;
3429                 b_prefix = o->b_prefix;
3430         }
3431
3432         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3433             (!one->mode || S_ISGITLINK(one->mode)) &&
3434             (!two->mode || S_ISGITLINK(two->mode))) {
3435                 show_submodule_diff_summary(o, one->path ? one->path : two->path,
3436                                 &one->oid, &two->oid,
3437                                 two->dirty_submodule);
3438                 return;
3439         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3440                    (!one->mode || S_ISGITLINK(one->mode)) &&
3441                    (!two->mode || S_ISGITLINK(two->mode))) {
3442                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3443                                 &one->oid, &two->oid,
3444                                 two->dirty_submodule);
3445                 return;
3446         }
3447
3448         if (o->flags.allow_textconv) {
3449                 textconv_one = get_textconv(o->repo, one);
3450                 textconv_two = get_textconv(o->repo, two);
3451         }
3452
3453         /* Never use a non-valid filename anywhere if at all possible */
3454         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3455         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3456
3457         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3458         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3459         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3460         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3461         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3462         if (lbl[0][0] == '/') {
3463                 /* /dev/null */
3464                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3465                 if (xfrm_msg)
3466                         strbuf_addstr(&header, xfrm_msg);
3467                 must_show_header = 1;
3468         }
3469         else if (lbl[1][0] == '/') {
3470                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3471                 if (xfrm_msg)
3472                         strbuf_addstr(&header, xfrm_msg);
3473                 must_show_header = 1;
3474         }
3475         else {
3476                 if (one->mode != two->mode) {
3477                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3478                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3479                         must_show_header = 1;
3480                 }
3481                 if (xfrm_msg)
3482                         strbuf_addstr(&header, xfrm_msg);
3483
3484                 /*
3485                  * we do not run diff between different kind
3486                  * of objects.
3487                  */
3488                 if ((one->mode ^ two->mode) & S_IFMT)
3489                         goto free_ab_and_return;
3490                 if (complete_rewrite &&
3491                     (textconv_one || !diff_filespec_is_binary(o->repo, one)) &&
3492                     (textconv_two || !diff_filespec_is_binary(o->repo, two))) {
3493                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3494                                          header.buf, header.len, 0);
3495                         strbuf_reset(&header);
3496                         emit_rewrite_diff(name_a, name_b, one, two,
3497                                           textconv_one, textconv_two, o);
3498                         o->found_changes = 1;
3499                         goto free_ab_and_return;
3500                 }
3501         }
3502
3503         if (o->irreversible_delete && lbl[1][0] == '/') {
3504                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3505                                  header.len, 0);
3506                 strbuf_reset(&header);
3507                 goto free_ab_and_return;
3508         } else if (!o->flags.text &&
3509                    ( (!textconv_one && diff_filespec_is_binary(o->repo, one)) ||
3510                      (!textconv_two && diff_filespec_is_binary(o->repo, two)) )) {
3511                 struct strbuf sb = STRBUF_INIT;
3512                 if (!one->data && !two->data &&
3513                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3514                     !o->flags.binary) {
3515                         if (oideq(&one->oid, &two->oid)) {
3516                                 if (must_show_header)
3517                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3518                                                          header.buf, header.len,
3519                                                          0);
3520                                 goto free_ab_and_return;
3521                         }
3522                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3523                                          header.buf, header.len, 0);
3524                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3525                                     diff_line_prefix(o), lbl[0], lbl[1]);
3526                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3527                                          sb.buf, sb.len, 0);
3528                         strbuf_release(&sb);
3529                         goto free_ab_and_return;
3530                 }
3531                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3532                     fill_mmfile(o->repo, &mf2, two) < 0)
3533                         die("unable to read files to diff");
3534                 /* Quite common confusing case */
3535                 if (mf1.size == mf2.size &&
3536                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3537                         if (must_show_header)
3538                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3539                                                  header.buf, header.len, 0);
3540                         goto free_ab_and_return;
3541                 }
3542                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3543                 strbuf_reset(&header);
3544                 if (o->flags.binary)
3545                         emit_binary_diff(o, &mf1, &mf2);
3546                 else {
3547                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3548                                     diff_line_prefix(o), lbl[0], lbl[1]);
3549                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3550                                          sb.buf, sb.len, 0);
3551                         strbuf_release(&sb);
3552                 }
3553                 o->found_changes = 1;
3554         } else {
3555                 /* Crazy xdl interfaces.. */
3556                 const char *diffopts;
3557                 const char *v;
3558                 xpparam_t xpp;
3559                 xdemitconf_t xecfg;
3560                 struct emit_callback ecbdata;
3561                 const struct userdiff_funcname *pe;
3562
3563                 if (must_show_header) {
3564                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3565                                          header.buf, header.len, 0);
3566                         strbuf_reset(&header);
3567                 }
3568
3569                 mf1.size = fill_textconv(o->repo, textconv_one, one, &mf1.ptr);
3570                 mf2.size = fill_textconv(o->repo, textconv_two, two, &mf2.ptr);
3571
3572                 pe = diff_funcname_pattern(o, one);
3573                 if (!pe)
3574                         pe = diff_funcname_pattern(o, two);
3575
3576                 memset(&xpp, 0, sizeof(xpp));
3577                 memset(&xecfg, 0, sizeof(xecfg));
3578                 memset(&ecbdata, 0, sizeof(ecbdata));
3579                 if (o->flags.suppress_diff_headers)
3580                         lbl[0] = NULL;
3581                 ecbdata.label_path = lbl;
3582                 ecbdata.color_diff = want_color(o->use_color);
3583                 ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
3584                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3585                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3586                 ecbdata.opt = o;
3587                 if (header.len && !o->flags.suppress_diff_headers)
3588                         ecbdata.header = &header;
3589                 xpp.flags = o->xdl_opts;
3590                 xpp.anchors = o->anchors;
3591                 xpp.anchors_nr = o->anchors_nr;
3592                 xecfg.ctxlen = o->context;
3593                 xecfg.interhunkctxlen = o->interhunkcontext;
3594                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3595                 if (o->flags.funccontext)
3596                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3597                 if (pe)
3598                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3599
3600                 diffopts = getenv("GIT_DIFF_OPTS");
3601                 if (!diffopts)
3602                         ;
3603                 else if (skip_prefix(diffopts, "--unified=", &v))
3604                         xecfg.ctxlen = strtoul(v, NULL, 10);
3605                 else if (skip_prefix(diffopts, "-u", &v))
3606                         xecfg.ctxlen = strtoul(v, NULL, 10);
3607
3608                 if (o->word_diff)
3609                         init_diff_words_data(&ecbdata, o, one, two);
3610                 if (xdi_diff_outf(&mf1, &mf2, NULL, fn_out_consume,
3611                                   &ecbdata, &xpp, &xecfg))
3612                         die("unable to generate diff for %s", one->path);
3613                 if (o->word_diff)
3614                         free_diff_words_data(&ecbdata);
3615                 if (textconv_one)
3616                         free(mf1.ptr);
3617                 if (textconv_two)
3618                         free(mf2.ptr);
3619                 xdiff_clear_find_func(&xecfg);
3620         }
3621
3622  free_ab_and_return:
3623         strbuf_release(&header);
3624         diff_free_filespec_data(one);
3625         diff_free_filespec_data(two);
3626         free(a_one);
3627         free(b_two);
3628         return;
3629 }
3630
3631 static char *get_compact_summary(const struct diff_filepair *p, int is_renamed)
3632 {
3633         if (!is_renamed) {
3634                 if (p->status == DIFF_STATUS_ADDED) {
3635                         if (S_ISLNK(p->two->mode))
3636                                 return "new +l";
3637                         else if ((p->two->mode & 0777) == 0755)
3638                                 return "new +x";
3639                         else
3640                                 return "new";
3641                 } else if (p->status == DIFF_STATUS_DELETED)
3642                         return "gone";
3643         }
3644         if (S_ISLNK(p->one->mode) && !S_ISLNK(p->two->mode))
3645                 return "mode -l";
3646         else if (!S_ISLNK(p->one->mode) && S_ISLNK(p->two->mode))
3647                 return "mode +l";
3648         else if ((p->one->mode & 0777) == 0644 &&
3649                  (p->two->mode & 0777) == 0755)
3650                 return "mode +x";
3651         else if ((p->one->mode & 0777) == 0755 &&
3652                  (p->two->mode & 0777) == 0644)
3653                 return "mode -x";
3654         return NULL;
3655 }
3656
3657 static void builtin_diffstat(const char *name_a, const char *name_b,
3658                              struct diff_filespec *one,
3659                              struct diff_filespec *two,
3660                              struct diffstat_t *diffstat,
3661                              struct diff_options *o,
3662                              struct diff_filepair *p)
3663 {
3664         mmfile_t mf1, mf2;
3665         struct diffstat_file *data;
3666         int same_contents;
3667         int complete_rewrite = 0;
3668
3669         if (!DIFF_PAIR_UNMERGED(p)) {
3670                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3671                         complete_rewrite = 1;
3672         }
3673
3674         data = diffstat_add(diffstat, name_a, name_b);
3675         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3676         if (o->flags.stat_with_summary)
3677                 data->comments = get_compact_summary(p, data->is_renamed);
3678
3679         if (!one || !two) {
3680                 data->is_unmerged = 1;
3681                 return;
3682         }
3683
3684         same_contents = oideq(&one->oid, &two->oid);
3685
3686         if (diff_filespec_is_binary(o->repo, one) ||
3687             diff_filespec_is_binary(o->repo, two)) {
3688                 data->is_binary = 1;
3689                 if (same_contents) {
3690                         data->added = 0;
3691                         data->deleted = 0;
3692                 } else {
3693                         data->added = diff_filespec_size(o->repo, two);
3694                         data->deleted = diff_filespec_size(o->repo, one);
3695                 }
3696         }
3697
3698         else if (complete_rewrite) {
3699                 diff_populate_filespec(o->repo, one, NULL);
3700                 diff_populate_filespec(o->repo, two, NULL);
3701                 data->deleted = count_lines(one->data, one->size);
3702                 data->added = count_lines(two->data, two->size);
3703         }
3704
3705         else if (!same_contents) {
3706                 /* Crazy xdl interfaces.. */
3707                 xpparam_t xpp;
3708                 xdemitconf_t xecfg;
3709
3710                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3711                     fill_mmfile(o->repo, &mf2, two) < 0)
3712                         die("unable to read files to diff");
3713
3714                 memset(&xpp, 0, sizeof(xpp));
3715                 memset(&xecfg, 0, sizeof(xecfg));
3716                 xpp.flags = o->xdl_opts;
3717                 xpp.anchors = o->anchors;
3718                 xpp.anchors_nr = o->anchors_nr;
3719                 xecfg.ctxlen = o->context;
3720                 xecfg.interhunkctxlen = o->interhunkcontext;
3721                 if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
3722                                   diffstat_consume, diffstat, &xpp, &xecfg))
3723                         die("unable to generate diffstat for %s", one->path);
3724
3725                 if (DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two)) {
3726                         struct diffstat_file *file =
3727                                 diffstat->files[diffstat->nr - 1];
3728                         /*
3729                          * Omit diffstats of modified files where nothing changed.
3730                          * Even if !same_contents, this might be the case due to
3731                          * ignoring whitespace changes, etc.
3732                          *
3733                          * But note that we special-case additions, deletions,
3734                          * renames, and mode changes as adding an empty file,
3735                          * for example is still of interest.
3736                          */
3737                         if ((p->status == DIFF_STATUS_MODIFIED)
3738                                 && !file->added
3739                                 && !file->deleted
3740                                 && one->mode == two->mode) {
3741                                 free_diffstat_file(file);
3742                                 diffstat->nr--;
3743                         }
3744                 }
3745         }
3746
3747         diff_free_filespec_data(one);
3748         diff_free_filespec_data(two);
3749 }
3750
3751 static void builtin_checkdiff(const char *name_a, const char *name_b,
3752                               const char *attr_path,
3753                               struct diff_filespec *one,
3754                               struct diff_filespec *two,
3755                               struct diff_options *o)
3756 {
3757         mmfile_t mf1, mf2;
3758         struct checkdiff_t data;
3759
3760         if (!two)
3761                 return;
3762
3763         memset(&data, 0, sizeof(data));
3764         data.filename = name_b ? name_b : name_a;
3765         data.lineno = 0;
3766         data.o = o;
3767         data.ws_rule = whitespace_rule(o->repo->index, attr_path);
3768         data.conflict_marker_size = ll_merge_marker_size(o->repo->index, attr_path);
3769
3770         if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3771             fill_mmfile(o->repo, &mf2, two) < 0)
3772                 die("unable to read files to diff");
3773
3774         /*
3775          * All the other codepaths check both sides, but not checking
3776          * the "old" side here is deliberate.  We are checking the newly
3777          * introduced changes, and as long as the "new" side is text, we
3778          * can and should check what it introduces.
3779          */
3780         if (diff_filespec_is_binary(o->repo, two))
3781                 goto free_and_return;
3782         else {
3783                 /* Crazy xdl interfaces.. */
3784                 xpparam_t xpp;
3785                 xdemitconf_t xecfg;
3786
3787                 memset(&xpp, 0, sizeof(xpp));
3788                 memset(&xecfg, 0, sizeof(xecfg));
3789                 xecfg.ctxlen = 1; /* at least one context line */
3790                 xpp.flags = 0;
3791                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume_hunk,
3792                                   checkdiff_consume, &data,
3793                                   &xpp, &xecfg))
3794                         die("unable to generate checkdiff for %s", one->path);
3795
3796                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3797                         struct emit_callback ecbdata;
3798                         int blank_at_eof;
3799
3800                         ecbdata.ws_rule = data.ws_rule;
3801                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3802                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3803
3804                         if (blank_at_eof) {
3805                                 static char *err;
3806                                 if (!err)
3807                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3808                                 fprintf(o->file, "%s:%d: %s.\n",
3809                                         data.filename, blank_at_eof, err);
3810                                 data.status = 1; /* report errors */
3811                         }
3812                 }
3813         }
3814  free_and_return:
3815         diff_free_filespec_data(one);
3816         diff_free_filespec_data(two);
3817         if (data.status)
3818                 o->flags.check_failed = 1;
3819 }
3820
3821 struct diff_filespec *alloc_filespec(const char *path)
3822 {
3823         struct diff_filespec *spec;
3824
3825         FLEXPTR_ALLOC_STR(spec, path, path);
3826         spec->count = 1;
3827         spec->is_binary = -1;
3828         return spec;
3829 }
3830
3831 void free_filespec(struct diff_filespec *spec)
3832 {
3833         if (!--spec->count) {
3834                 diff_free_filespec_data(spec);
3835                 free(spec);
3836         }
3837 }
3838
3839 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3840                    int oid_valid, unsigned short mode)
3841 {
3842         if (mode) {
3843                 spec->mode = canon_mode(mode);
3844                 oidcpy(&spec->oid, oid);
3845                 spec->oid_valid = oid_valid;
3846         }
3847 }
3848
3849 /*
3850  * Given a name and sha1 pair, if the index tells us the file in
3851  * the work tree has that object contents, return true, so that
3852  * prepare_temp_file() does not have to inflate and extract.
3853  */
3854 static int reuse_worktree_file(struct index_state *istate,
3855                                const char *name,
3856                                const struct object_id *oid,
3857                                int want_file)
3858 {
3859         const struct cache_entry *ce;
3860         struct stat st;
3861         int pos, len;
3862
3863         /*
3864          * We do not read the cache ourselves here, because the
3865          * benchmark with my previous version that always reads cache
3866          * shows that it makes things worse for diff-tree comparing
3867          * two linux-2.6 kernel trees in an already checked out work
3868          * tree.  This is because most diff-tree comparisons deal with
3869          * only a small number of files, while reading the cache is
3870          * expensive for a large project, and its cost outweighs the
3871          * savings we get by not inflating the object to a temporary
3872          * file.  Practically, this code only helps when we are used
3873          * by diff-cache --cached, which does read the cache before
3874          * calling us.
3875          */
3876         if (!istate->cache)
3877                 return 0;
3878
3879         /* We want to avoid the working directory if our caller
3880          * doesn't need the data in a normal file, this system
3881          * is rather slow with its stat/open/mmap/close syscalls,
3882          * and the object is contained in a pack file.  The pack
3883          * is probably already open and will be faster to obtain
3884          * the data through than the working directory.  Loose
3885          * objects however would tend to be slower as they need
3886          * to be individually opened and inflated.
3887          */
3888         if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
3889                 return 0;
3890
3891         /*
3892          * Similarly, if we'd have to convert the file contents anyway, that
3893          * makes the optimization not worthwhile.
3894          */
3895         if (!want_file && would_convert_to_git(istate, name))
3896                 return 0;
3897
3898         len = strlen(name);
3899         pos = index_name_pos(istate, name, len);
3900         if (pos < 0)
3901                 return 0;
3902         ce = istate->cache[pos];
3903
3904         /*
3905          * This is not the sha1 we are looking for, or
3906          * unreusable because it is not a regular file.
3907          */
3908         if (!oideq(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3909                 return 0;
3910
3911         /*
3912          * If ce is marked as "assume unchanged", there is no
3913          * guarantee that work tree matches what we are looking for.
3914          */
3915         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3916                 return 0;
3917
3918         /*
3919          * If ce matches the file in the work tree, we can reuse it.
3920          */
3921         if (ce_uptodate(ce) ||
3922             (!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0)))
3923                 return 1;
3924
3925         return 0;
3926 }
3927
3928 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3929 {
3930         struct strbuf buf = STRBUF_INIT;
3931         char *dirty = "";
3932
3933         /* Are we looking at the work tree? */
3934         if (s->dirty_submodule)
3935                 dirty = "-dirty";
3936
3937         strbuf_addf(&buf, "Subproject commit %s%s\n",
3938                     oid_to_hex(&s->oid), dirty);
3939         s->size = buf.len;
3940         if (size_only) {
3941                 s->data = NULL;
3942                 strbuf_release(&buf);
3943         } else {
3944                 s->data = strbuf_detach(&buf, NULL);
3945                 s->should_free = 1;
3946         }
3947         return 0;
3948 }
3949
3950 /*
3951  * While doing rename detection and pickaxe operation, we may need to
3952  * grab the data for the blob (or file) for our own in-core comparison.
3953  * diff_filespec has data and size fields for this purpose.
3954  */
3955 int diff_populate_filespec(struct repository *r,
3956                            struct diff_filespec *s,
3957                            const struct diff_populate_filespec_options *options)
3958 {
3959         int size_only = options ? options->check_size_only : 0;
3960         int check_binary = options ? options->check_binary : 0;
3961         int err = 0;
3962         int conv_flags = global_conv_flags_eol;
3963         /*
3964          * demote FAIL to WARN to allow inspecting the situation
3965          * instead of refusing.
3966          */
3967         if (conv_flags & CONV_EOL_RNDTRP_DIE)
3968                 conv_flags = CONV_EOL_RNDTRP_WARN;
3969
3970         if (!DIFF_FILE_VALID(s))
3971                 die("internal error: asking to populate invalid file.");
3972         if (S_ISDIR(s->mode))
3973                 return -1;
3974
3975         if (s->data)
3976                 return 0;
3977
3978         if (size_only && 0 < s->size)
3979                 return 0;
3980
3981         if (S_ISGITLINK(s->mode))
3982                 return diff_populate_gitlink(s, size_only);
3983
3984         if (!s->oid_valid ||
3985             reuse_worktree_file(r->index, s->path, &s->oid, 0)) {
3986                 struct strbuf buf = STRBUF_INIT;
3987                 struct stat st;
3988                 int fd;
3989
3990                 if (lstat(s->path, &st) < 0) {
3991                 err_empty:
3992                         err = -1;
3993                 empty:
3994                         s->data = (char *)"";
3995                         s->size = 0;
3996                         return err;
3997                 }
3998                 s->size = xsize_t(st.st_size);
3999                 if (!s->size)
4000                         goto empty;
4001                 if (S_ISLNK(st.st_mode)) {
4002                         struct strbuf sb = STRBUF_INIT;
4003
4004                         if (strbuf_readlink(&sb, s->path, s->size))
4005                                 goto err_empty;
4006                         s->size = sb.len;
4007                         s->data = strbuf_detach(&sb, NULL);
4008                         s->should_free = 1;
4009                         return 0;
4010                 }
4011
4012                 /*
4013                  * Even if the caller would be happy with getting
4014                  * only the size, we cannot return early at this
4015                  * point if the path requires us to run the content
4016                  * conversion.
4017                  */
4018                 if (size_only && !would_convert_to_git(r->index, s->path))
4019                         return 0;
4020
4021                 /*
4022                  * Note: this check uses xsize_t(st.st_size) that may
4023                  * not be the true size of the blob after it goes
4024                  * through convert_to_git().  This may not strictly be
4025                  * correct, but the whole point of big_file_threshold
4026                  * and is_binary check being that we want to avoid
4027                  * opening the file and inspecting the contents, this
4028                  * is probably fine.
4029                  */
4030                 if (check_binary &&
4031                     s->size > big_file_threshold && s->is_binary == -1) {
4032                         s->is_binary = 1;
4033                         return 0;
4034                 }
4035                 fd = open(s->path, O_RDONLY);
4036                 if (fd < 0)
4037                         goto err_empty;
4038                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
4039                 close(fd);
4040                 s->should_munmap = 1;
4041
4042                 /*
4043                  * Convert from working tree format to canonical git format
4044                  */
4045                 if (convert_to_git(r->index, s->path, s->data, s->size, &buf, conv_flags)) {
4046                         size_t size = 0;
4047                         munmap(s->data, s->size);
4048                         s->should_munmap = 0;
4049                         s->data = strbuf_detach(&buf, &size);
4050                         s->size = size;
4051                         s->should_free = 1;
4052                 }
4053         }
4054         else {
4055                 struct object_info info = {
4056                         .sizep = &s->size
4057                 };
4058
4059                 if (!(size_only || check_binary))
4060                         /*
4061                          * Set contentp, since there is no chance that merely
4062                          * the size is sufficient.
4063                          */
4064                         info.contentp = &s->data;
4065
4066                 if (options && options->missing_object_cb) {
4067                         if (!oid_object_info_extended(r, &s->oid, &info,
4068                                                       OBJECT_INFO_LOOKUP_REPLACE |
4069                                                       OBJECT_INFO_SKIP_FETCH_OBJECT))
4070                                 goto object_read;
4071                         options->missing_object_cb(options->missing_object_data);
4072                 }
4073                 if (oid_object_info_extended(r, &s->oid, &info,
4074                                              OBJECT_INFO_LOOKUP_REPLACE))
4075                         die("unable to read %s", oid_to_hex(&s->oid));
4076
4077 object_read:
4078                 if (size_only || check_binary) {
4079                         if (size_only)
4080                                 return 0;
4081                         if (s->size > big_file_threshold && s->is_binary == -1) {
4082                                 s->is_binary = 1;
4083                                 return 0;
4084                         }
4085                 }
4086                 if (!info.contentp) {
4087                         info.contentp = &s->data;
4088                         if (oid_object_info_extended(r, &s->oid, &info,
4089                                                      OBJECT_INFO_LOOKUP_REPLACE))
4090                                 die("unable to read %s", oid_to_hex(&s->oid));
4091                 }
4092                 s->should_free = 1;
4093         }
4094         return 0;
4095 }
4096
4097 void diff_free_filespec_blob(struct diff_filespec *s)
4098 {
4099         if (s->should_free)
4100                 free(s->data);
4101         else if (s->should_munmap)
4102                 munmap(s->data, s->size);
4103
4104         if (s->should_free || s->should_munmap) {
4105                 s->should_free = s->should_munmap = 0;
4106                 s->data = NULL;
4107         }
4108 }
4109
4110 void diff_free_filespec_data(struct diff_filespec *s)
4111 {
4112         diff_free_filespec_blob(s);
4113         FREE_AND_NULL(s->cnt_data);
4114 }
4115
4116 static void prep_temp_blob(struct index_state *istate,
4117                            const char *path, struct diff_tempfile *temp,
4118                            void *blob,
4119                            unsigned long size,
4120                            const struct object_id *oid,
4121                            int mode)
4122 {
4123         struct strbuf buf = STRBUF_INIT;
4124         struct strbuf tempfile = STRBUF_INIT;
4125         char *path_dup = xstrdup(path);
4126         const char *base = basename(path_dup);
4127         struct checkout_metadata meta;
4128
4129         init_checkout_metadata(&meta, NULL, NULL, oid);
4130
4131         /* Generate "XXXXXX_basename.ext" */
4132         strbuf_addstr(&tempfile, "XXXXXX_");
4133         strbuf_addstr(&tempfile, base);
4134
4135         temp->tempfile = mks_tempfile_ts(tempfile.buf, strlen(base) + 1);
4136         if (!temp->tempfile)
4137                 die_errno("unable to create temp-file");
4138         if (convert_to_working_tree(istate, path,
4139                         (const char *)blob, (size_t)size, &buf, &meta)) {
4140                 blob = buf.buf;
4141                 size = buf.len;
4142         }
4143         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
4144             close_tempfile_gently(temp->tempfile))
4145                 die_errno("unable to write temp-file");
4146         temp->name = get_tempfile_path(temp->tempfile);
4147         oid_to_hex_r(temp->hex, oid);
4148         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
4149         strbuf_release(&buf);
4150         strbuf_release(&tempfile);
4151         free(path_dup);
4152 }
4153
4154 static struct diff_tempfile *prepare_temp_file(struct repository *r,
4155                                                const char *name,
4156                                                struct diff_filespec *one)
4157 {
4158         struct diff_tempfile *temp = claim_diff_tempfile();
4159
4160         if (!DIFF_FILE_VALID(one)) {
4161         not_a_valid_file:
4162                 /* A '-' entry produces this for file-2, and
4163                  * a '+' entry produces this for file-1.
4164                  */
4165                 temp->name = "/dev/null";
4166                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
4167                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
4168                 return temp;
4169         }
4170
4171         if (!S_ISGITLINK(one->mode) &&
4172             (!one->oid_valid ||
4173              reuse_worktree_file(r->index, name, &one->oid, 1))) {
4174                 struct stat st;
4175                 if (lstat(name, &st) < 0) {
4176                         if (errno == ENOENT)
4177                                 goto not_a_valid_file;
4178                         die_errno("stat(%s)", name);
4179                 }
4180                 if (S_ISLNK(st.st_mode)) {
4181                         struct strbuf sb = STRBUF_INIT;
4182                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
4183                                 die_errno("readlink(%s)", name);
4184                         prep_temp_blob(r->index, name, temp, sb.buf, sb.len,
4185                                        (one->oid_valid ?
4186                                         &one->oid : &null_oid),
4187                                        (one->oid_valid ?
4188                                         one->mode : S_IFLNK));
4189                         strbuf_release(&sb);
4190                 }
4191                 else {
4192                         /* we can borrow from the file in the work tree */
4193                         temp->name = name;
4194                         if (!one->oid_valid)
4195                                 oid_to_hex_r(temp->hex, &null_oid);
4196                         else
4197                                 oid_to_hex_r(temp->hex, &one->oid);
4198                         /* Even though we may sometimes borrow the
4199                          * contents from the work tree, we always want
4200                          * one->mode.  mode is trustworthy even when
4201                          * !(one->oid_valid), as long as
4202                          * DIFF_FILE_VALID(one).
4203                          */
4204                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
4205                 }
4206                 return temp;
4207         }
4208         else {
4209                 if (diff_populate_filespec(r, one, NULL))
4210                         die("cannot read data blob for %s", one->path);
4211                 prep_temp_blob(r->index, name, temp,
4212                                one->data, one->size,
4213                                &one->oid, one->mode);
4214         }
4215         return temp;
4216 }
4217
4218 static void add_external_diff_name(struct repository *r,
4219                                    struct strvec *argv,
4220                                    const char *name,
4221                                    struct diff_filespec *df)
4222 {
4223         struct diff_tempfile *temp = prepare_temp_file(r, name, df);
4224         strvec_push(argv, temp->name);
4225         strvec_push(argv, temp->hex);
4226         strvec_push(argv, temp->mode);
4227 }
4228
4229 /* An external diff command takes:
4230  *
4231  * diff-cmd name infile1 infile1-sha1 infile1-mode \
4232  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
4233  *
4234  */
4235 static void run_external_diff(const char *pgm,
4236                               const char *name,
4237                               const char *other,
4238                               struct diff_filespec *one,
4239                               struct diff_filespec *two,
4240                               const char *xfrm_msg,
4241                               struct diff_options *o)
4242 {
4243         struct strvec argv = STRVEC_INIT;
4244         struct strvec env = STRVEC_INIT;
4245         struct diff_queue_struct *q = &diff_queued_diff;
4246
4247         strvec_push(&argv, pgm);
4248         strvec_push(&argv, name);
4249
4250         if (one && two) {
4251                 add_external_diff_name(o->repo, &argv, name, one);
4252                 if (!other)
4253                         add_external_diff_name(o->repo, &argv, name, two);
4254                 else {
4255                         add_external_diff_name(o->repo, &argv, other, two);
4256                         strvec_push(&argv, other);
4257                         strvec_push(&argv, xfrm_msg);
4258                 }
4259         }
4260
4261         strvec_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
4262         strvec_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
4263
4264         diff_free_filespec_data(one);
4265         diff_free_filespec_data(two);
4266         if (run_command_v_opt_cd_env(argv.v, RUN_USING_SHELL, NULL, env.v))
4267                 die(_("external diff died, stopping at %s"), name);
4268
4269         remove_tempfile();
4270         strvec_clear(&argv);
4271         strvec_clear(&env);
4272 }
4273
4274 static int similarity_index(struct diff_filepair *p)
4275 {
4276         return p->score * 100 / MAX_SCORE;
4277 }
4278
4279 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
4280 {
4281         if (startup_info->have_repository)
4282                 return find_unique_abbrev(oid, abbrev);
4283         else {
4284                 char *hex = oid_to_hex(oid);
4285                 if (abbrev < 0)
4286                         abbrev = FALLBACK_DEFAULT_ABBREV;
4287                 if (abbrev > the_hash_algo->hexsz)
4288                         BUG("oid abbreviation out of range: %d", abbrev);
4289                 if (abbrev)
4290                         hex[abbrev] = '\0';
4291                 return hex;
4292         }
4293 }
4294
4295 static void fill_metainfo(struct strbuf *msg,
4296                           const char *name,
4297                           const char *other,
4298                           struct diff_filespec *one,
4299                           struct diff_filespec *two,
4300                           struct diff_options *o,
4301                           struct diff_filepair *p,
4302                           int *must_show_header,
4303                           int use_color)
4304 {
4305         const char *set = diff_get_color(use_color, DIFF_METAINFO);
4306         const char *reset = diff_get_color(use_color, DIFF_RESET);
4307         const char *line_prefix = diff_line_prefix(o);
4308
4309         *must_show_header = 1;
4310         strbuf_init(msg, PATH_MAX * 2 + 300);
4311         switch (p->status) {
4312         case DIFF_STATUS_COPIED:
4313                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4314                             line_prefix, set, similarity_index(p));
4315                 strbuf_addf(msg, "%s\n%s%scopy from ",
4316                             reset,  line_prefix, set);
4317                 quote_c_style(name, msg, NULL, 0);
4318                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
4319                 quote_c_style(other, msg, NULL, 0);
4320                 strbuf_addf(msg, "%s\n", reset);
4321                 break;
4322         case DIFF_STATUS_RENAMED:
4323                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4324                             line_prefix, set, similarity_index(p));
4325                 strbuf_addf(msg, "%s\n%s%srename from ",
4326                             reset, line_prefix, set);
4327                 quote_c_style(name, msg, NULL, 0);
4328                 strbuf_addf(msg, "%s\n%s%srename to ",
4329                             reset, line_prefix, set);
4330                 quote_c_style(other, msg, NULL, 0);
4331                 strbuf_addf(msg, "%s\n", reset);
4332                 break;
4333         case DIFF_STATUS_MODIFIED:
4334                 if (p->score) {
4335                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
4336                                     line_prefix,
4337                                     set, similarity_index(p), reset);
4338                         break;
4339                 }
4340                 /* fallthru */
4341         default:
4342                 *must_show_header = 0;
4343         }
4344         if (one && two && !oideq(&one->oid, &two->oid)) {
4345                 const unsigned hexsz = the_hash_algo->hexsz;
4346                 int abbrev = o->abbrev ? o->abbrev : DEFAULT_ABBREV;
4347
4348                 if (o->flags.full_index)
4349                         abbrev = hexsz;
4350
4351                 if (o->flags.binary) {
4352                         mmfile_t mf;
4353                         if ((!fill_mmfile(o->repo, &mf, one) &&
4354                              diff_filespec_is_binary(o->repo, one)) ||
4355                             (!fill_mmfile(o->repo, &mf, two) &&
4356                              diff_filespec_is_binary(o->repo, two)))
4357                                 abbrev = hexsz;
4358                 }
4359                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
4360                             diff_abbrev_oid(&one->oid, abbrev),
4361                             diff_abbrev_oid(&two->oid, abbrev));
4362                 if (one->mode == two->mode)
4363                         strbuf_addf(msg, " %06o", one->mode);
4364                 strbuf_addf(msg, "%s\n", reset);
4365         }
4366 }
4367
4368 static void run_diff_cmd(const char *pgm,
4369                          const char *name,
4370                          const char *other,
4371                          const char *attr_path,
4372                          struct diff_filespec *one,
4373                          struct diff_filespec *two,
4374                          struct strbuf *msg,
4375                          struct diff_options *o,
4376                          struct diff_filepair *p)
4377 {
4378         const char *xfrm_msg = NULL;
4379         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
4380         int must_show_header = 0;
4381
4382
4383         if (o->flags.allow_external) {
4384                 struct userdiff_driver *drv;
4385
4386                 drv = userdiff_find_by_path(o->repo->index, attr_path);
4387                 if (drv && drv->external)
4388                         pgm = drv->external;
4389         }
4390
4391         if (msg) {
4392                 /*
4393                  * don't use colors when the header is intended for an
4394                  * external diff driver
4395                  */
4396                 fill_metainfo(msg, name, other, one, two, o, p,
4397                               &must_show_header,
4398                               want_color(o->use_color) && !pgm);
4399                 xfrm_msg = msg->len ? msg->buf : NULL;
4400         }
4401
4402         if (pgm) {
4403                 run_external_diff(pgm, name, other, one, two, xfrm_msg, o);
4404                 return;
4405         }
4406         if (one && two)
4407                 builtin_diff(name, other ? other : name,
4408                              one, two, xfrm_msg, must_show_header,
4409                              o, complete_rewrite);
4410         else
4411                 fprintf(o->file, "* Unmerged path %s\n", name);
4412 }
4413
4414 static void diff_fill_oid_info(struct diff_filespec *one, struct index_state *istate)
4415 {
4416         if (DIFF_FILE_VALID(one)) {
4417                 if (!one->oid_valid) {
4418                         struct stat st;
4419                         if (one->is_stdin) {
4420                                 oidclr(&one->oid);
4421                                 return;
4422                         }
4423                         if (lstat(one->path, &st) < 0)
4424                                 die_errno("stat '%s'", one->path);
4425                         if (index_path(istate, &one->oid, one->path, &st, 0))
4426                                 die("cannot hash %s", one->path);
4427                 }
4428         }
4429         else
4430                 oidclr(&one->oid);
4431 }
4432
4433 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
4434 {
4435         /* Strip the prefix but do not molest /dev/null and absolute paths */
4436         if (*namep && !is_absolute_path(*namep)) {
4437                 *namep += prefix_length;
4438                 if (**namep == '/')
4439                         ++*namep;
4440         }
4441         if (*otherp && !is_absolute_path(*otherp)) {
4442                 *otherp += prefix_length;
4443                 if (**otherp == '/')
4444                         ++*otherp;
4445         }
4446 }
4447
4448 static void run_diff(struct diff_filepair *p, struct diff_options *o)
4449 {
4450         const char *pgm = external_diff();
4451         struct strbuf msg;
4452         struct diff_filespec *one = p->one;
4453         struct diff_filespec *two = p->two;
4454         const char *name;
4455         const char *other;
4456         const char *attr_path;
4457
4458         name  = one->path;
4459         other = (strcmp(name, two->path) ? two->path : NULL);
4460         attr_path = name;
4461         if (o->prefix_length)
4462                 strip_prefix(o->prefix_length, &name, &other);
4463
4464         if (!o->flags.allow_external)
4465                 pgm = NULL;
4466
4467         if (DIFF_PAIR_UNMERGED(p)) {
4468                 run_diff_cmd(pgm, name, NULL, attr_path,
4469                              NULL, NULL, NULL, o, p);
4470                 return;
4471         }
4472
4473         diff_fill_oid_info(one, o->repo->index);
4474         diff_fill_oid_info(two, o->repo->index);
4475
4476         if (!pgm &&
4477             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4478             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4479                 /*
4480                  * a filepair that changes between file and symlink
4481                  * needs to be split into deletion and creation.
4482                  */
4483                 struct diff_filespec *null = alloc_filespec(two->path);
4484                 run_diff_cmd(NULL, name, other, attr_path,
4485                              one, null, &msg,
4486                              o, p);
4487                 free(null);
4488                 strbuf_release(&msg);
4489
4490                 null = alloc_filespec(one->path);
4491                 run_diff_cmd(NULL, name, other, attr_path,
4492                              null, two, &msg, o, p);
4493                 free(null);
4494         }
4495         else
4496                 run_diff_cmd(pgm, name, other, attr_path,
4497                              one, two, &msg, o, p);
4498
4499         strbuf_release(&msg);
4500 }
4501
4502 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4503                          struct diffstat_t *diffstat)
4504 {
4505         const char *name;
4506         const char *other;
4507
4508         if (DIFF_PAIR_UNMERGED(p)) {
4509                 /* unmerged */
4510                 builtin_diffstat(p->one->path, NULL, NULL, NULL,
4511                                  diffstat, o, p);
4512                 return;
4513         }
4514
4515         name = p->one->path;
4516         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4517
4518         if (o->prefix_length)
4519                 strip_prefix(o->prefix_length, &name, &other);
4520
4521         diff_fill_oid_info(p->one, o->repo->index);
4522         diff_fill_oid_info(p->two, o->repo->index);
4523
4524         builtin_diffstat(name, other, p->one, p->two,
4525                          diffstat, o, p);
4526 }
4527
4528 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4529 {
4530         const char *name;
4531         const char *other;
4532         const char *attr_path;
4533
4534         if (DIFF_PAIR_UNMERGED(p)) {
4535                 /* unmerged */
4536                 return;
4537         }
4538
4539         name = p->one->path;
4540         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4541         attr_path = other ? other : name;
4542
4543         if (o->prefix_length)
4544                 strip_prefix(o->prefix_length, &name, &other);
4545
4546         diff_fill_oid_info(p->one, o->repo->index);
4547         diff_fill_oid_info(p->two, o->repo->index);
4548
4549         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4550 }
4551
4552 static void prep_parse_options(struct diff_options *options);
4553
4554 void repo_diff_setup(struct repository *r, struct diff_options *options)
4555 {
4556         memcpy(options, &default_diff_options, sizeof(*options));
4557
4558         options->file = stdout;
4559         options->repo = r;
4560
4561         options->output_indicators[OUTPUT_INDICATOR_NEW] = '+';
4562         options->output_indicators[OUTPUT_INDICATOR_OLD] = '-';
4563         options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = ' ';
4564         options->abbrev = DEFAULT_ABBREV;
4565         options->line_termination = '\n';
4566         options->break_opt = -1;
4567         options->rename_limit = -1;
4568         options->dirstat_permille = diff_dirstat_permille_default;
4569         options->context = diff_context_default;
4570         options->interhunkcontext = diff_interhunk_context_default;
4571         options->ws_error_highlight = ws_error_highlight_default;
4572         options->flags.rename_empty = 1;
4573         options->flags.relative_name = diff_relative;
4574         options->objfind = NULL;
4575
4576         /* pathchange left =NULL by default */
4577         options->change = diff_change;
4578         options->add_remove = diff_addremove;
4579         options->use_color = diff_use_color_default;
4580         options->detect_rename = diff_detect_rename_default;
4581         options->xdl_opts |= diff_algorithm;
4582         if (diff_indent_heuristic)
4583                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4584
4585         options->orderfile = diff_order_file_cfg;
4586
4587         if (diff_no_prefix) {
4588                 options->a_prefix = options->b_prefix = "";
4589         } else if (!diff_mnemonic_prefix) {
4590                 options->a_prefix = "a/";
4591                 options->b_prefix = "b/";
4592         }
4593
4594         options->color_moved = diff_color_moved_default;
4595         options->color_moved_ws_handling = diff_color_moved_ws_default;
4596
4597         prep_parse_options(options);
4598 }
4599
4600 void diff_setup_done(struct diff_options *options)
4601 {
4602         unsigned check_mask = DIFF_FORMAT_NAME |
4603                               DIFF_FORMAT_NAME_STATUS |
4604                               DIFF_FORMAT_CHECKDIFF |
4605                               DIFF_FORMAT_NO_OUTPUT;
4606         /*
4607          * This must be signed because we're comparing against a potentially
4608          * negative value.
4609          */
4610         const int hexsz = the_hash_algo->hexsz;
4611
4612         if (options->set_default)
4613                 options->set_default(options);
4614
4615         if (HAS_MULTI_BITS(options->output_format & check_mask))
4616                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4617
4618         if (HAS_MULTI_BITS(options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
4619                 die(_("-G, -S and --find-object are mutually exclusive"));
4620
4621         /*
4622          * Most of the time we can say "there are changes"
4623          * only by checking if there are changed paths, but
4624          * --ignore-whitespace* options force us to look
4625          * inside contents.
4626          */
4627
4628         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4629                 options->flags.diff_from_contents = 1;
4630         else
4631                 options->flags.diff_from_contents = 0;
4632
4633         if (options->flags.find_copies_harder)
4634                 options->detect_rename = DIFF_DETECT_COPY;
4635
4636         if (!options->flags.relative_name)
4637                 options->prefix = NULL;
4638         if (options->prefix)
4639                 options->prefix_length = strlen(options->prefix);
4640         else
4641                 options->prefix_length = 0;
4642
4643         if (options->output_format & (DIFF_FORMAT_NAME |
4644                                       DIFF_FORMAT_NAME_STATUS |
4645                                       DIFF_FORMAT_CHECKDIFF |
4646                                       DIFF_FORMAT_NO_OUTPUT))
4647                 options->output_format &= ~(DIFF_FORMAT_RAW |
4648                                             DIFF_FORMAT_NUMSTAT |
4649                                             DIFF_FORMAT_DIFFSTAT |
4650                                             DIFF_FORMAT_SHORTSTAT |
4651                                             DIFF_FORMAT_DIRSTAT |
4652                                             DIFF_FORMAT_SUMMARY |
4653                                             DIFF_FORMAT_PATCH);
4654
4655         /*
4656          * These cases always need recursive; we do not drop caller-supplied
4657          * recursive bits for other formats here.
4658          */
4659         if (options->output_format & (DIFF_FORMAT_PATCH |
4660                                       DIFF_FORMAT_NUMSTAT |
4661                                       DIFF_FORMAT_DIFFSTAT |
4662                                       DIFF_FORMAT_SHORTSTAT |
4663                                       DIFF_FORMAT_DIRSTAT |
4664                                       DIFF_FORMAT_SUMMARY |
4665                                       DIFF_FORMAT_CHECKDIFF))
4666                 options->flags.recursive = 1;
4667         /*
4668          * Also pickaxe would not work very well if you do not say recursive
4669          */
4670         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
4671                 options->flags.recursive = 1;
4672         /*
4673          * When patches are generated, submodules diffed against the work tree
4674          * must be checked for dirtiness too so it can be shown in the output
4675          */
4676         if (options->output_format & DIFF_FORMAT_PATCH)
4677                 options->flags.dirty_submodules = 1;
4678
4679         if (options->detect_rename && options->rename_limit < 0)
4680                 options->rename_limit = diff_rename_limit_default;
4681         if (hexsz < options->abbrev)
4682                 options->abbrev = hexsz; /* full */
4683
4684         /*
4685          * It does not make sense to show the first hit we happened
4686          * to have found.  It does not make sense not to return with
4687          * exit code in such a case either.
4688          */
4689         if (options->flags.quick) {
4690                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4691                 options->flags.exit_with_status = 1;
4692         }
4693
4694         options->diff_path_counter = 0;
4695
4696         if (options->flags.follow_renames && options->pathspec.nr != 1)
4697                 die(_("--follow requires exactly one pathspec"));
4698
4699         if (!options->use_color || external_diff())
4700                 options->color_moved = 0;
4701
4702         FREE_AND_NULL(options->parseopts);
4703 }
4704
4705 int parse_long_opt(const char *opt, const char **argv,
4706                    const char **optarg)
4707 {
4708         const char *arg = argv[0];
4709         if (!skip_prefix(arg, "--", &arg))
4710                 return 0;
4711         if (!skip_prefix(arg, opt, &arg))
4712                 return 0;
4713         if (*arg == '=') { /* stuck form: --option=value */
4714                 *optarg = arg + 1;
4715                 return 1;
4716         }
4717         if (*arg != '\0')
4718                 return 0;
4719         /* separate form: --option value */
4720         if (!argv[1])
4721                 die("Option '--%s' requires a value", opt);
4722         *optarg = argv[1];
4723         return 2;
4724 }
4725
4726 static int diff_opt_stat(const struct option *opt, const char *value, int unset)
4727 {
4728         struct diff_options *options = opt->value;
4729         int width = options->stat_width;
4730         int name_width = options->stat_name_width;
4731         int graph_width = options->stat_graph_width;
4732         int count = options->stat_count;
4733         char *end;
4734
4735         BUG_ON_OPT_NEG(unset);
4736
4737         if (!strcmp(opt->long_name, "stat")) {
4738                 if (value) {
4739                         width = strtoul(value, &end, 10);
4740                         if (*end == ',')
4741                                 name_width = strtoul(end+1, &end, 10);
4742                         if (*end == ',')
4743                                 count = strtoul(end+1, &end, 10);
4744                         if (*end)
4745                                 return error(_("invalid --stat value: %s"), value);
4746                 }
4747         } else if (!strcmp(opt->long_name, "stat-width")) {
4748                 width = strtoul(value, &end, 10);
4749                 if (*end)
4750                         return error(_("%s expects a numerical value"),
4751                                      opt->long_name);
4752         } else if (!strcmp(opt->long_name, "stat-name-width")) {
4753                 name_width = strtoul(value, &end, 10);
4754                 if (*end)
4755                         return error(_("%s expects a numerical value"),
4756                                      opt->long_name);
4757         } else if (!strcmp(opt->long_name, "stat-graph-width")) {
4758                 graph_width = strtoul(value, &end, 10);
4759                 if (*end)
4760                         return error(_("%s expects a numerical value"),
4761                                      opt->long_name);
4762         } else if (!strcmp(opt->long_name, "stat-count")) {
4763                 count = strtoul(value, &end, 10);
4764                 if (*end)
4765                         return error(_("%s expects a numerical value"),
4766                                      opt->long_name);
4767         } else
4768                 BUG("%s should not get here", opt->long_name);
4769
4770         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4771         options->stat_name_width = name_width;
4772         options->stat_graph_width = graph_width;
4773         options->stat_width = width;
4774         options->stat_count = count;
4775         return 0;
4776 }
4777
4778 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4779 {
4780         struct strbuf errmsg = STRBUF_INIT;
4781         if (parse_dirstat_params(options, params, &errmsg))
4782                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4783                     errmsg.buf);
4784         strbuf_release(&errmsg);
4785         /*
4786          * The caller knows a dirstat-related option is given from the command
4787          * line; allow it to say "return this_function();"
4788          */
4789         options->output_format |= DIFF_FORMAT_DIRSTAT;
4790         return 1;
4791 }
4792
4793 static const char diff_status_letters[] = {
4794         DIFF_STATUS_ADDED,
4795         DIFF_STATUS_COPIED,
4796         DIFF_STATUS_DELETED,
4797         DIFF_STATUS_MODIFIED,
4798         DIFF_STATUS_RENAMED,
4799         DIFF_STATUS_TYPE_CHANGED,
4800         DIFF_STATUS_UNKNOWN,
4801         DIFF_STATUS_UNMERGED,
4802         DIFF_STATUS_FILTER_AON,
4803         DIFF_STATUS_FILTER_BROKEN,
4804         '\0',
4805 };
4806
4807 static unsigned int filter_bit['Z' + 1];
4808
4809 static void prepare_filter_bits(void)
4810 {
4811         int i;
4812
4813         if (!filter_bit[DIFF_STATUS_ADDED]) {
4814                 for (i = 0; diff_status_letters[i]; i++)
4815                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4816         }
4817 }
4818
4819 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4820 {
4821         return opt->filter & filter_bit[(int) status];
4822 }
4823
4824 unsigned diff_filter_bit(char status)
4825 {
4826         prepare_filter_bits();
4827         return filter_bit[(int) status];
4828 }
4829
4830 static int diff_opt_diff_filter(const struct option *option,
4831                                 const char *optarg, int unset)
4832 {
4833         struct diff_options *opt = option->value;
4834         int i, optch;
4835
4836         BUG_ON_OPT_NEG(unset);
4837         prepare_filter_bits();
4838
4839         /*
4840          * If there is a negation e.g. 'd' in the input, and we haven't
4841          * initialized the filter field with another --diff-filter, start
4842          * from full set of bits, except for AON.
4843          */
4844         if (!opt->filter) {
4845                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4846                         if (optch < 'a' || 'z' < optch)
4847                                 continue;
4848                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4849                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4850                         break;
4851                 }
4852         }
4853
4854         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4855                 unsigned int bit;
4856                 int negate;
4857
4858                 if ('a' <= optch && optch <= 'z') {
4859                         negate = 1;
4860                         optch = toupper(optch);
4861                 } else {
4862                         negate = 0;
4863                 }
4864
4865                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4866                 if (!bit)
4867                         return error(_("unknown change class '%c' in --diff-filter=%s"),
4868                                      optarg[i], optarg);
4869                 if (negate)
4870                         opt->filter &= ~bit;
4871                 else
4872                         opt->filter |= bit;
4873         }
4874         return 0;
4875 }
4876
4877 static void enable_patch_output(int *fmt)
4878 {
4879         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4880         *fmt |= DIFF_FORMAT_PATCH;
4881 }
4882
4883 static int diff_opt_ws_error_highlight(const struct option *option,
4884                                        const char *arg, int unset)
4885 {
4886         struct diff_options *opt = option->value;
4887         int val = parse_ws_error_highlight(arg);
4888
4889         BUG_ON_OPT_NEG(unset);
4890         if (val < 0)
4891                 return error(_("unknown value after ws-error-highlight=%.*s"),
4892                              -1 - val, arg);
4893         opt->ws_error_highlight = val;
4894         return 0;
4895 }
4896
4897 static int diff_opt_find_object(const struct option *option,
4898                                 const char *arg, int unset)
4899 {
4900         struct diff_options *opt = option->value;
4901         struct object_id oid;
4902
4903         BUG_ON_OPT_NEG(unset);
4904         if (get_oid(arg, &oid))
4905                 return error(_("unable to resolve '%s'"), arg);
4906
4907         if (!opt->objfind)
4908                 opt->objfind = xcalloc(1, sizeof(*opt->objfind));
4909
4910         opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND;
4911         opt->flags.recursive = 1;
4912         opt->flags.tree_in_recursive = 1;
4913         oidset_insert(opt->objfind, &oid);
4914         return 0;
4915 }
4916
4917 static int diff_opt_anchored(const struct option *opt,
4918                              const char *arg, int unset)
4919 {
4920         struct diff_options *options = opt->value;
4921
4922         BUG_ON_OPT_NEG(unset);
4923         options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4924         ALLOC_GROW(options->anchors, options->anchors_nr + 1,
4925                    options->anchors_alloc);
4926         options->anchors[options->anchors_nr++] = xstrdup(arg);
4927         return 0;
4928 }
4929
4930 static int diff_opt_binary(const struct option *opt,
4931                            const char *arg, int unset)
4932 {
4933         struct diff_options *options = opt->value;
4934
4935         BUG_ON_OPT_NEG(unset);
4936         BUG_ON_OPT_ARG(arg);
4937         enable_patch_output(&options->output_format);
4938         options->flags.binary = 1;
4939         return 0;
4940 }
4941
4942 static int diff_opt_break_rewrites(const struct option *opt,
4943                                    const char *arg, int unset)
4944 {
4945         int *break_opt = opt->value;
4946         int opt1, opt2;
4947
4948         BUG_ON_OPT_NEG(unset);
4949         if (!arg)
4950                 arg = "";
4951         opt1 = parse_rename_score(&arg);
4952         if (*arg == 0)
4953                 opt2 = 0;
4954         else if (*arg != '/')
4955                 return error(_("%s expects <n>/<m> form"), opt->long_name);
4956         else {
4957                 arg++;
4958                 opt2 = parse_rename_score(&arg);
4959         }
4960         if (*arg != 0)
4961                 return error(_("%s expects <n>/<m> form"), opt->long_name);
4962         *break_opt = opt1 | (opt2 << 16);
4963         return 0;
4964 }
4965
4966 static int diff_opt_char(const struct option *opt,
4967                          const char *arg, int unset)
4968 {
4969         char *value = opt->value;
4970
4971         BUG_ON_OPT_NEG(unset);
4972         if (arg[1])
4973                 return error(_("%s expects a character, got '%s'"),
4974                              opt->long_name, arg);
4975         *value = arg[0];
4976         return 0;
4977 }
4978
4979 static int diff_opt_color_moved(const struct option *opt,
4980                                 const char *arg, int unset)
4981 {
4982         struct diff_options *options = opt->value;
4983
4984         if (unset) {
4985                 options->color_moved = COLOR_MOVED_NO;
4986         } else if (!arg) {
4987                 if (diff_color_moved_default)
4988                         options->color_moved = diff_color_moved_default;
4989                 if (options->color_moved == COLOR_MOVED_NO)
4990                         options->color_moved = COLOR_MOVED_DEFAULT;
4991         } else {
4992                 int cm = parse_color_moved(arg);
4993                 if (cm < 0)
4994                         return error(_("bad --color-moved argument: %s"), arg);
4995                 options->color_moved = cm;
4996         }
4997         return 0;
4998 }
4999
5000 static int diff_opt_color_moved_ws(const struct option *opt,
5001                                    const char *arg, int unset)
5002 {
5003         struct diff_options *options = opt->value;
5004         unsigned cm;
5005
5006         if (unset) {
5007                 options->color_moved_ws_handling = 0;
5008                 return 0;
5009         }
5010
5011         cm = parse_color_moved_ws(arg);
5012         if (cm & COLOR_MOVED_WS_ERROR)
5013                 return error(_("invalid mode '%s' in --color-moved-ws"), arg);
5014         options->color_moved_ws_handling = cm;
5015         return 0;
5016 }
5017
5018 static int diff_opt_color_words(const struct option *opt,
5019                                 const char *arg, int unset)
5020 {
5021         struct diff_options *options = opt->value;
5022
5023         BUG_ON_OPT_NEG(unset);
5024         options->use_color = 1;
5025         options->word_diff = DIFF_WORDS_COLOR;
5026         options->word_regex = arg;
5027         return 0;
5028 }
5029
5030 static int diff_opt_compact_summary(const struct option *opt,
5031                                     const char *arg, int unset)
5032 {
5033         struct diff_options *options = opt->value;
5034
5035         BUG_ON_OPT_ARG(arg);
5036         if (unset) {
5037                 options->flags.stat_with_summary = 0;
5038         } else {
5039                 options->flags.stat_with_summary = 1;
5040                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
5041         }
5042         return 0;
5043 }
5044
5045 static int diff_opt_diff_algorithm(const struct option *opt,
5046                                    const char *arg, int unset)
5047 {
5048         struct diff_options *options = opt->value;
5049         long value = parse_algorithm_value(arg);
5050
5051         BUG_ON_OPT_NEG(unset);
5052         if (value < 0)
5053                 return error(_("option diff-algorithm accepts \"myers\", "
5054                                "\"minimal\", \"patience\" and \"histogram\""));
5055
5056         /* clear out previous settings */
5057         DIFF_XDL_CLR(options, NEED_MINIMAL);
5058         options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
5059         options->xdl_opts |= value;
5060         return 0;
5061 }
5062
5063 static int diff_opt_dirstat(const struct option *opt,
5064                             const char *arg, int unset)
5065 {
5066         struct diff_options *options = opt->value;
5067
5068         BUG_ON_OPT_NEG(unset);
5069         if (!strcmp(opt->long_name, "cumulative")) {
5070                 if (arg)
5071                         BUG("how come --cumulative take a value?");
5072                 arg = "cumulative";
5073         } else if (!strcmp(opt->long_name, "dirstat-by-file"))
5074                 parse_dirstat_opt(options, "files");
5075         parse_dirstat_opt(options, arg ? arg : "");
5076         return 0;
5077 }
5078
5079 static int diff_opt_find_copies(const struct option *opt,
5080                                 const char *arg, int unset)
5081 {
5082         struct diff_options *options = opt->value;
5083
5084         BUG_ON_OPT_NEG(unset);
5085         if (!arg)
5086                 arg = "";
5087         options->rename_score = parse_rename_score(&arg);
5088         if (*arg != 0)
5089                 return error(_("invalid argument to %s"), opt->long_name);
5090
5091         if (options->detect_rename == DIFF_DETECT_COPY)
5092                 options->flags.find_copies_harder = 1;
5093         else
5094                 options->detect_rename = DIFF_DETECT_COPY;
5095
5096         return 0;
5097 }
5098
5099 static int diff_opt_find_renames(const struct option *opt,
5100                                  const char *arg, int unset)
5101 {
5102         struct diff_options *options = opt->value;
5103
5104         BUG_ON_OPT_NEG(unset);
5105         if (!arg)
5106                 arg = "";
5107         options->rename_score = parse_rename_score(&arg);
5108         if (*arg != 0)
5109                 return error(_("invalid argument to %s"), opt->long_name);
5110
5111         options->detect_rename = DIFF_DETECT_RENAME;
5112         return 0;
5113 }
5114
5115 static int diff_opt_follow(const struct option *opt,
5116                            const char *arg, int unset)
5117 {
5118         struct diff_options *options = opt->value;
5119
5120         BUG_ON_OPT_ARG(arg);
5121         if (unset) {
5122                 options->flags.follow_renames = 0;
5123                 options->flags.default_follow_renames = 0;
5124         } else {
5125                 options->flags.follow_renames = 1;
5126         }
5127         return 0;
5128 }
5129
5130 static int diff_opt_ignore_submodules(const struct option *opt,
5131                                       const char *arg, int unset)
5132 {
5133         struct diff_options *options = opt->value;
5134
5135         BUG_ON_OPT_NEG(unset);
5136         if (!arg)
5137                 arg = "all";
5138         options->flags.override_submodule_config = 1;
5139         handle_ignore_submodules_arg(options, arg);
5140         return 0;
5141 }
5142
5143 static int diff_opt_line_prefix(const struct option *opt,
5144                                 const char *optarg, int unset)
5145 {
5146         struct diff_options *options = opt->value;
5147
5148         BUG_ON_OPT_NEG(unset);
5149         options->line_prefix = optarg;
5150         options->line_prefix_length = strlen(options->line_prefix);
5151         graph_setup_line_prefix(options);
5152         return 0;
5153 }
5154
5155 static int diff_opt_no_prefix(const struct option *opt,
5156                               const char *optarg, int unset)
5157 {
5158         struct diff_options *options = opt->value;
5159
5160         BUG_ON_OPT_NEG(unset);
5161         BUG_ON_OPT_ARG(optarg);
5162         options->a_prefix = "";
5163         options->b_prefix = "";
5164         return 0;
5165 }
5166
5167 static enum parse_opt_result diff_opt_output(struct parse_opt_ctx_t *ctx,
5168                                              const struct option *opt,
5169                                              const char *arg, int unset)
5170 {
5171         struct diff_options *options = opt->value;
5172         char *path;
5173
5174         BUG_ON_OPT_NEG(unset);
5175         path = prefix_filename(ctx->prefix, arg);
5176         options->file = xfopen(path, "w");
5177         options->close_file = 1;
5178         if (options->use_color != GIT_COLOR_ALWAYS)
5179                 options->use_color = GIT_COLOR_NEVER;
5180         free(path);
5181         return 0;
5182 }
5183
5184 static int diff_opt_patience(const struct option *opt,
5185                              const char *arg, int unset)
5186 {
5187         struct diff_options *options = opt->value;
5188         int i;
5189
5190         BUG_ON_OPT_NEG(unset);
5191         BUG_ON_OPT_ARG(arg);
5192         options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
5193         /*
5194          * Both --patience and --anchored use PATIENCE_DIFF
5195          * internally, so remove any anchors previously
5196          * specified.
5197          */
5198         for (i = 0; i < options->anchors_nr; i++)
5199                 free(options->anchors[i]);
5200         options->anchors_nr = 0;
5201         return 0;
5202 }
5203
5204 static int diff_opt_pickaxe_regex(const struct option *opt,
5205                                   const char *arg, int unset)
5206 {
5207         struct diff_options *options = opt->value;
5208
5209         BUG_ON_OPT_NEG(unset);
5210         options->pickaxe = arg;
5211         options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
5212         return 0;
5213 }
5214
5215 static int diff_opt_pickaxe_string(const struct option *opt,
5216                                    const char *arg, int unset)
5217 {
5218         struct diff_options *options = opt->value;
5219
5220         BUG_ON_OPT_NEG(unset);
5221         options->pickaxe = arg;
5222         options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
5223         return 0;
5224 }
5225
5226 static int diff_opt_relative(const struct option *opt,
5227                              const char *arg, int unset)
5228 {
5229         struct diff_options *options = opt->value;
5230
5231         options->flags.relative_name = !unset;
5232         if (arg)
5233                 options->prefix = arg;
5234         return 0;
5235 }
5236
5237 static int diff_opt_submodule(const struct option *opt,
5238                               const char *arg, int unset)
5239 {
5240         struct diff_options *options = opt->value;
5241
5242         BUG_ON_OPT_NEG(unset);
5243         if (!arg)
5244                 arg = "log";
5245         if (parse_submodule_params(options, arg))
5246                 return error(_("failed to parse --submodule option parameter: '%s'"),
5247                              arg);
5248         return 0;
5249 }
5250
5251 static int diff_opt_textconv(const struct option *opt,
5252                              const char *arg, int unset)
5253 {
5254         struct diff_options *options = opt->value;
5255
5256         BUG_ON_OPT_ARG(arg);
5257         if (unset) {
5258                 options->flags.allow_textconv = 0;
5259         } else {
5260                 options->flags.allow_textconv = 1;
5261                 options->flags.textconv_set_via_cmdline = 1;
5262         }
5263         return 0;
5264 }
5265
5266 static int diff_opt_unified(const struct option *opt,
5267                             const char *arg, int unset)
5268 {
5269         struct diff_options *options = opt->value;
5270         char *s;
5271
5272         BUG_ON_OPT_NEG(unset);
5273
5274         if (arg) {
5275                 options->context = strtol(arg, &s, 10);
5276                 if (*s)
5277                         return error(_("%s expects a numerical value"), "--unified");
5278         }
5279         enable_patch_output(&options->output_format);
5280
5281         return 0;
5282 }
5283
5284 static int diff_opt_word_diff(const struct option *opt,
5285                               const char *arg, int unset)
5286 {
5287         struct diff_options *options = opt->value;
5288
5289         BUG_ON_OPT_NEG(unset);
5290         if (arg) {
5291                 if (!strcmp(arg, "plain"))
5292                         options->word_diff = DIFF_WORDS_PLAIN;
5293                 else if (!strcmp(arg, "color")) {
5294                         options->use_color = 1;
5295                         options->word_diff = DIFF_WORDS_COLOR;
5296                 }
5297                 else if (!strcmp(arg, "porcelain"))
5298                         options->word_diff = DIFF_WORDS_PORCELAIN;
5299                 else if (!strcmp(arg, "none"))
5300                         options->word_diff = DIFF_WORDS_NONE;
5301                 else
5302                         return error(_("bad --word-diff argument: %s"), arg);
5303         } else {
5304                 if (options->word_diff == DIFF_WORDS_NONE)
5305                         options->word_diff = DIFF_WORDS_PLAIN;
5306         }
5307         return 0;
5308 }
5309
5310 static int diff_opt_word_diff_regex(const struct option *opt,
5311                                     const char *arg, int unset)
5312 {
5313         struct diff_options *options = opt->value;
5314
5315         BUG_ON_OPT_NEG(unset);
5316         if (options->word_diff == DIFF_WORDS_NONE)
5317                 options->word_diff = DIFF_WORDS_PLAIN;
5318         options->word_regex = arg;
5319         return 0;
5320 }
5321
5322 static void prep_parse_options(struct diff_options *options)
5323 {
5324         struct option parseopts[] = {
5325                 OPT_GROUP(N_("Diff output format options")),
5326                 OPT_BITOP('p', "patch", &options->output_format,
5327                           N_("generate patch"),
5328                           DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
5329                 OPT_BIT_F('s', "no-patch", &options->output_format,
5330                           N_("suppress diff output"),
5331                           DIFF_FORMAT_NO_OUTPUT, PARSE_OPT_NONEG),
5332                 OPT_BITOP('u', NULL, &options->output_format,
5333                           N_("generate patch"),
5334                           DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
5335                 OPT_CALLBACK_F('U', "unified", options, N_("<n>"),
5336                                N_("generate diffs with <n> lines context"),
5337                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_unified),
5338                 OPT_BOOL('W', "function-context", &options->flags.funccontext,
5339                          N_("generate diffs with <n> lines context")),
5340                 OPT_BIT_F(0, "raw", &options->output_format,
5341                           N_("generate the diff in raw format"),
5342                           DIFF_FORMAT_RAW, PARSE_OPT_NONEG),
5343                 OPT_BITOP(0, "patch-with-raw", &options->output_format,
5344                           N_("synonym for '-p --raw'"),
5345                           DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW,
5346                           DIFF_FORMAT_NO_OUTPUT),
5347                 OPT_BITOP(0, "patch-with-stat", &options->output_format,
5348                           N_("synonym for '-p --stat'"),
5349                           DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT,
5350                           DIFF_FORMAT_NO_OUTPUT),
5351                 OPT_BIT_F(0, "numstat", &options->output_format,
5352                           N_("machine friendly --stat"),
5353                           DIFF_FORMAT_NUMSTAT, PARSE_OPT_NONEG),
5354                 OPT_BIT_F(0, "shortstat", &options->output_format,
5355                           N_("output only the last line of --stat"),
5356                           DIFF_FORMAT_SHORTSTAT, PARSE_OPT_NONEG),
5357                 OPT_CALLBACK_F('X', "dirstat", options, N_("<param1,param2>..."),
5358                                N_("output the distribution of relative amount of changes for each sub-directory"),
5359                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5360                                diff_opt_dirstat),
5361                 OPT_CALLBACK_F(0, "cumulative", options, NULL,
5362                                N_("synonym for --dirstat=cumulative"),
5363                                PARSE_OPT_NONEG | PARSE_OPT_NOARG,
5364                                diff_opt_dirstat),
5365                 OPT_CALLBACK_F(0, "dirstat-by-file", options, N_("<param1,param2>..."),
5366                                N_("synonym for --dirstat=files,param1,param2..."),
5367                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5368                                diff_opt_dirstat),
5369                 OPT_BIT_F(0, "check", &options->output_format,
5370                           N_("warn if changes introduce conflict markers or whitespace errors"),
5371                           DIFF_FORMAT_CHECKDIFF, PARSE_OPT_NONEG),
5372                 OPT_BIT_F(0, "summary", &options->output_format,
5373                           N_("condensed summary such as creations, renames and mode changes"),
5374                           DIFF_FORMAT_SUMMARY, PARSE_OPT_NONEG),
5375                 OPT_BIT_F(0, "name-only", &options->output_format,
5376                           N_("show only names of changed files"),
5377                           DIFF_FORMAT_NAME, PARSE_OPT_NONEG),
5378                 OPT_BIT_F(0, "name-status", &options->output_format,
5379                           N_("show only names and status of changed files"),
5380                           DIFF_FORMAT_NAME_STATUS, PARSE_OPT_NONEG),
5381                 OPT_CALLBACK_F(0, "stat", options, N_("<width>[,<name-width>[,<count>]]"),
5382                                N_("generate diffstat"),
5383                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_stat),
5384                 OPT_CALLBACK_F(0, "stat-width", options, N_("<width>"),
5385                                N_("generate diffstat with a given width"),
5386                                PARSE_OPT_NONEG, diff_opt_stat),
5387                 OPT_CALLBACK_F(0, "stat-name-width", options, N_("<width>"),
5388                                N_("generate diffstat with a given name width"),
5389                                PARSE_OPT_NONEG, diff_opt_stat),
5390                 OPT_CALLBACK_F(0, "stat-graph-width", options, N_("<width>"),
5391                                N_("generate diffstat with a given graph width"),
5392                                PARSE_OPT_NONEG, diff_opt_stat),
5393                 OPT_CALLBACK_F(0, "stat-count", options, N_("<count>"),
5394                                N_("generate diffstat with limited lines"),
5395                                PARSE_OPT_NONEG, diff_opt_stat),
5396                 OPT_CALLBACK_F(0, "compact-summary", options, NULL,
5397                                N_("generate compact summary in diffstat"),
5398                                PARSE_OPT_NOARG, diff_opt_compact_summary),
5399                 OPT_CALLBACK_F(0, "binary", options, NULL,
5400                                N_("output a binary diff that can be applied"),
5401                                PARSE_OPT_NONEG | PARSE_OPT_NOARG, diff_opt_binary),
5402                 OPT_BOOL(0, "full-index", &options->flags.full_index,
5403                          N_("show full pre- and post-image object names on the \"index\" lines")),
5404                 OPT_COLOR_FLAG(0, "color", &options->use_color,
5405                                N_("show colored diff")),
5406                 OPT_CALLBACK_F(0, "ws-error-highlight", options, N_("<kind>"),
5407                                N_("highlight whitespace errors in the 'context', 'old' or 'new' lines in the diff"),
5408                                PARSE_OPT_NONEG, diff_opt_ws_error_highlight),
5409                 OPT_SET_INT('z', NULL, &options->line_termination,
5410                             N_("do not munge pathnames and use NULs as output field terminators in --raw or --numstat"),
5411                             0),
5412                 OPT__ABBREV(&options->abbrev),
5413                 OPT_STRING_F(0, "src-prefix", &options->a_prefix, N_("<prefix>"),
5414                              N_("show the given source prefix instead of \"a/\""),
5415                              PARSE_OPT_NONEG),
5416                 OPT_STRING_F(0, "dst-prefix", &options->b_prefix, N_("<prefix>"),
5417                              N_("show the given destination prefix instead of \"b/\""),
5418                              PARSE_OPT_NONEG),
5419                 OPT_CALLBACK_F(0, "line-prefix", options, N_("<prefix>"),
5420                                N_("prepend an additional prefix to every line of output"),
5421                                PARSE_OPT_NONEG, diff_opt_line_prefix),
5422                 OPT_CALLBACK_F(0, "no-prefix", options, NULL,
5423                                N_("do not show any source or destination prefix"),
5424                                PARSE_OPT_NONEG | PARSE_OPT_NOARG, diff_opt_no_prefix),
5425                 OPT_INTEGER_F(0, "inter-hunk-context", &options->interhunkcontext,
5426                               N_("show context between diff hunks up to the specified number of lines"),
5427                               PARSE_OPT_NONEG),
5428                 OPT_CALLBACK_F(0, "output-indicator-new",
5429                                &options->output_indicators[OUTPUT_INDICATOR_NEW],
5430                                N_("<char>"),
5431                                N_("specify the character to indicate a new line instead of '+'"),
5432                                PARSE_OPT_NONEG, diff_opt_char),
5433                 OPT_CALLBACK_F(0, "output-indicator-old",
5434                                &options->output_indicators[OUTPUT_INDICATOR_OLD],
5435                                N_("<char>"),
5436                                N_("specify the character to indicate an old line instead of '-'"),
5437                                PARSE_OPT_NONEG, diff_opt_char),
5438                 OPT_CALLBACK_F(0, "output-indicator-context",
5439                                &options->output_indicators[OUTPUT_INDICATOR_CONTEXT],
5440                                N_("<char>"),
5441                                N_("specify the character to indicate a context instead of ' '"),
5442                                PARSE_OPT_NONEG, diff_opt_char),
5443
5444                 OPT_GROUP(N_("Diff rename options")),
5445                 OPT_CALLBACK_F('B', "break-rewrites", &options->break_opt, N_("<n>[/<m>]"),
5446                                N_("break complete rewrite changes into pairs of delete and create"),
5447                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5448                                diff_opt_break_rewrites),
5449                 OPT_CALLBACK_F('M', "find-renames", options, N_("<n>"),
5450                                N_("detect renames"),
5451                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5452                                diff_opt_find_renames),
5453                 OPT_SET_INT_F('D', "irreversible-delete", &options->irreversible_delete,
5454                               N_("omit the preimage for deletes"),
5455                               1, PARSE_OPT_NONEG),
5456                 OPT_CALLBACK_F('C', "find-copies", options, N_("<n>"),
5457                                N_("detect copies"),
5458                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5459                                diff_opt_find_copies),
5460                 OPT_BOOL(0, "find-copies-harder", &options->flags.find_copies_harder,
5461                          N_("use unmodified files as source to find copies")),
5462                 OPT_SET_INT_F(0, "no-renames", &options->detect_rename,
5463                               N_("disable rename detection"),
5464                               0, PARSE_OPT_NONEG),
5465                 OPT_BOOL(0, "rename-empty", &options->flags.rename_empty,
5466                          N_("use empty blobs as rename source")),
5467                 OPT_CALLBACK_F(0, "follow", options, NULL,
5468                                N_("continue listing the history of a file beyond renames"),
5469                                PARSE_OPT_NOARG, diff_opt_follow),
5470                 OPT_INTEGER('l', NULL, &options->rename_limit,
5471                             N_("prevent rename/copy detection if the number of rename/copy targets exceeds given limit")),
5472
5473                 OPT_GROUP(N_("Diff algorithm options")),
5474                 OPT_BIT(0, "minimal", &options->xdl_opts,
5475                         N_("produce the smallest possible diff"),
5476                         XDF_NEED_MINIMAL),
5477                 OPT_BIT_F('w', "ignore-all-space", &options->xdl_opts,
5478                           N_("ignore whitespace when comparing lines"),
5479                           XDF_IGNORE_WHITESPACE, PARSE_OPT_NONEG),
5480                 OPT_BIT_F('b', "ignore-space-change", &options->xdl_opts,
5481                           N_("ignore changes in amount of whitespace"),
5482                           XDF_IGNORE_WHITESPACE_CHANGE, PARSE_OPT_NONEG),
5483                 OPT_BIT_F(0, "ignore-space-at-eol", &options->xdl_opts,
5484                           N_("ignore changes in whitespace at EOL"),
5485                           XDF_IGNORE_WHITESPACE_AT_EOL, PARSE_OPT_NONEG),
5486                 OPT_BIT_F(0, "ignore-cr-at-eol", &options->xdl_opts,
5487                           N_("ignore carrier-return at the end of line"),
5488                           XDF_IGNORE_CR_AT_EOL, PARSE_OPT_NONEG),
5489                 OPT_BIT_F(0, "ignore-blank-lines", &options->xdl_opts,
5490                           N_("ignore changes whose lines are all blank"),
5491                           XDF_IGNORE_BLANK_LINES, PARSE_OPT_NONEG),
5492                 OPT_BIT(0, "indent-heuristic", &options->xdl_opts,
5493                         N_("heuristic to shift diff hunk boundaries for easy reading"),
5494                         XDF_INDENT_HEURISTIC),
5495                 OPT_CALLBACK_F(0, "patience", options, NULL,
5496                                N_("generate diff using the \"patience diff\" algorithm"),
5497                                PARSE_OPT_NONEG | PARSE_OPT_NOARG,
5498                                diff_opt_patience),
5499                 OPT_BITOP(0, "histogram", &options->xdl_opts,
5500                           N_("generate diff using the \"histogram diff\" algorithm"),
5501                           XDF_HISTOGRAM_DIFF, XDF_DIFF_ALGORITHM_MASK),
5502                 OPT_CALLBACK_F(0, "diff-algorithm", options, N_("<algorithm>"),
5503                                N_("choose a diff algorithm"),
5504                                PARSE_OPT_NONEG, diff_opt_diff_algorithm),
5505                 OPT_CALLBACK_F(0, "anchored", options, N_("<text>"),
5506                                N_("generate diff using the \"anchored diff\" algorithm"),
5507                                PARSE_OPT_NONEG, diff_opt_anchored),
5508                 OPT_CALLBACK_F(0, "word-diff", options, N_("<mode>"),
5509                                N_("show word diff, using <mode> to delimit changed words"),
5510                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_word_diff),
5511                 OPT_CALLBACK_F(0, "word-diff-regex", options, N_("<regex>"),
5512                                N_("use <regex> to decide what a word is"),
5513                                PARSE_OPT_NONEG, diff_opt_word_diff_regex),
5514                 OPT_CALLBACK_F(0, "color-words", options, N_("<regex>"),
5515                                N_("equivalent to --word-diff=color --word-diff-regex=<regex>"),
5516                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_color_words),
5517                 OPT_CALLBACK_F(0, "color-moved", options, N_("<mode>"),
5518                                N_("moved lines of code are colored differently"),
5519                                PARSE_OPT_OPTARG, diff_opt_color_moved),
5520                 OPT_CALLBACK_F(0, "color-moved-ws", options, N_("<mode>"),
5521                                N_("how white spaces are ignored in --color-moved"),
5522                                0, diff_opt_color_moved_ws),
5523
5524                 OPT_GROUP(N_("Other diff options")),
5525                 OPT_CALLBACK_F(0, "relative", options, N_("<prefix>"),
5526                                N_("when run from subdir, exclude changes outside and show relative paths"),
5527                                PARSE_OPT_OPTARG,
5528                                diff_opt_relative),
5529                 OPT_BOOL('a', "text", &options->flags.text,
5530                          N_("treat all files as text")),
5531                 OPT_BOOL('R', NULL, &options->flags.reverse_diff,
5532                          N_("swap two inputs, reverse the diff")),
5533                 OPT_BOOL(0, "exit-code", &options->flags.exit_with_status,
5534                          N_("exit with 1 if there were differences, 0 otherwise")),
5535                 OPT_BOOL(0, "quiet", &options->flags.quick,
5536                          N_("disable all output of the program")),
5537                 OPT_BOOL(0, "ext-diff", &options->flags.allow_external,
5538                          N_("allow an external diff helper to be executed")),
5539                 OPT_CALLBACK_F(0, "textconv", options, NULL,
5540                                N_("run external text conversion filters when comparing binary files"),
5541                                PARSE_OPT_NOARG, diff_opt_textconv),
5542                 OPT_CALLBACK_F(0, "ignore-submodules", options, N_("<when>"),
5543                                N_("ignore changes to submodules in the diff generation"),
5544                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5545                                diff_opt_ignore_submodules),
5546                 OPT_CALLBACK_F(0, "submodule", options, N_("<format>"),
5547                                N_("specify how differences in submodules are shown"),
5548                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5549                                diff_opt_submodule),
5550                 OPT_SET_INT_F(0, "ita-invisible-in-index", &options->ita_invisible_in_index,
5551                               N_("hide 'git add -N' entries from the index"),
5552                               1, PARSE_OPT_NONEG),
5553                 OPT_SET_INT_F(0, "ita-visible-in-index", &options->ita_invisible_in_index,
5554                               N_("treat 'git add -N' entries as real in the index"),
5555                               0, PARSE_OPT_NONEG),
5556                 OPT_CALLBACK_F('S', NULL, options, N_("<string>"),
5557                                N_("look for differences that change the number of occurrences of the specified string"),
5558                                0, diff_opt_pickaxe_string),
5559                 OPT_CALLBACK_F('G', NULL, options, N_("<regex>"),
5560                                N_("look for differences that change the number of occurrences of the specified regex"),
5561                                0, diff_opt_pickaxe_regex),
5562                 OPT_BIT_F(0, "pickaxe-all", &options->pickaxe_opts,
5563                           N_("show all changes in the changeset with -S or -G"),
5564                           DIFF_PICKAXE_ALL, PARSE_OPT_NONEG),
5565                 OPT_BIT_F(0, "pickaxe-regex", &options->pickaxe_opts,
5566                           N_("treat <string> in -S as extended POSIX regular expression"),
5567                           DIFF_PICKAXE_REGEX, PARSE_OPT_NONEG),
5568                 OPT_FILENAME('O', NULL, &options->orderfile,
5569                              N_("control the order in which files appear in the output")),
5570                 OPT_CALLBACK_F(0, "find-object", options, N_("<object-id>"),
5571                                N_("look for differences that change the number of occurrences of the specified object"),
5572                                PARSE_OPT_NONEG, diff_opt_find_object),
5573                 OPT_CALLBACK_F(0, "diff-filter", options, N_("[(A|C|D|M|R|T|U|X|B)...[*]]"),
5574                                N_("select files by diff type"),
5575                                PARSE_OPT_NONEG, diff_opt_diff_filter),
5576                 { OPTION_CALLBACK, 0, "output", options, N_("<file>"),
5577                   N_("Output to a specific file"),
5578                   PARSE_OPT_NONEG, NULL, 0, diff_opt_output },
5579
5580                 OPT_END()
5581         };
5582
5583         ALLOC_ARRAY(options->parseopts, ARRAY_SIZE(parseopts));
5584         memcpy(options->parseopts, parseopts, sizeof(parseopts));
5585 }
5586
5587 int diff_opt_parse(struct diff_options *options,
5588                    const char **av, int ac, const char *prefix)
5589 {
5590         if (!prefix)
5591                 prefix = "";
5592
5593         ac = parse_options(ac, av, prefix, options->parseopts, NULL,
5594                            PARSE_OPT_KEEP_DASHDASH |
5595                            PARSE_OPT_KEEP_UNKNOWN |
5596                            PARSE_OPT_NO_INTERNAL_HELP |
5597                            PARSE_OPT_ONE_SHOT |
5598                            PARSE_OPT_STOP_AT_NON_OPTION);
5599
5600         return ac;
5601 }
5602
5603 int parse_rename_score(const char **cp_p)
5604 {
5605         unsigned long num, scale;
5606         int ch, dot;
5607         const char *cp = *cp_p;
5608
5609         num = 0;
5610         scale = 1;
5611         dot = 0;
5612         for (;;) {
5613                 ch = *cp;
5614                 if ( !dot && ch == '.' ) {
5615                         scale = 1;
5616                         dot = 1;
5617                 } else if ( ch == '%' ) {
5618                         scale = dot ? scale*100 : 100;
5619                         cp++;   /* % is always at the end */
5620                         break;
5621                 } else if ( ch >= '0' && ch <= '9' ) {
5622                         if ( scale < 100000 ) {
5623                                 scale *= 10;
5624                                 num = (num*10) + (ch-'0');
5625                         }
5626                 } else {
5627                         break;
5628                 }
5629                 cp++;
5630         }
5631         *cp_p = cp;
5632
5633         /* user says num divided by scale and we say internally that
5634          * is MAX_SCORE * num / scale.
5635          */
5636         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
5637 }
5638
5639 struct diff_queue_struct diff_queued_diff;
5640
5641 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
5642 {
5643         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
5644         queue->queue[queue->nr++] = dp;
5645 }
5646
5647 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
5648                                  struct diff_filespec *one,
5649                                  struct diff_filespec *two)
5650 {
5651         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
5652         dp->one = one;
5653         dp->two = two;
5654         if (queue)
5655                 diff_q(queue, dp);
5656         return dp;
5657 }
5658
5659 void diff_free_filepair(struct diff_filepair *p)
5660 {
5661         free_filespec(p->one);
5662         free_filespec(p->two);
5663         free(p);
5664 }
5665
5666 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
5667 {
5668         int abblen;
5669         const char *abbrev;
5670
5671         /* Do we want all 40 hex characters? */
5672         if (len == the_hash_algo->hexsz)
5673                 return oid_to_hex(oid);
5674
5675         /* An abbreviated value is fine, possibly followed by an ellipsis. */
5676         abbrev = diff_abbrev_oid(oid, len);
5677
5678         if (!print_sha1_ellipsis())
5679                 return abbrev;
5680
5681         abblen = strlen(abbrev);
5682
5683         /*
5684          * In well-behaved cases, where the abbreviated result is the
5685          * same as the requested length, append three dots after the
5686          * abbreviation (hence the whole logic is limited to the case
5687          * where abblen < 37); when the actual abbreviated result is a
5688          * bit longer than the requested length, we reduce the number
5689          * of dots so that they match the well-behaved ones.  However,
5690          * if the actual abbreviation is longer than the requested
5691          * length by more than three, we give up on aligning, and add
5692          * three dots anyway, to indicate that the output is not the
5693          * full object name.  Yes, this may be suboptimal, but this
5694          * appears only in "diff --raw --abbrev" output and it is not
5695          * worth the effort to change it now.  Note that this would
5696          * likely to work fine when the automatic sizing of default
5697          * abbreviation length is used--we would be fed -1 in "len" in
5698          * that case, and will end up always appending three-dots, but
5699          * the automatic sizing is supposed to give abblen that ensures
5700          * uniqueness across all objects (statistically speaking).
5701          */
5702         if (abblen < the_hash_algo->hexsz - 3) {
5703                 static char hex[GIT_MAX_HEXSZ + 1];
5704                 if (len < abblen && abblen <= len + 2)
5705                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
5706                 else
5707                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
5708                 return hex;
5709         }
5710
5711         return oid_to_hex(oid);
5712 }
5713
5714 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5715 {
5716         int line_termination = opt->line_termination;
5717         int inter_name_termination = line_termination ? '\t' : '\0';
5718
5719         fprintf(opt->file, "%s", diff_line_prefix(opt));
5720         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5721                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5722                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5723                 fprintf(opt->file, "%s ",
5724                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5725         }
5726         if (p->score) {
5727                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5728                         inter_name_termination);
5729         } else {
5730                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5731         }
5732
5733         if (p->status == DIFF_STATUS_COPIED ||
5734             p->status == DIFF_STATUS_RENAMED) {
5735                 const char *name_a, *name_b;
5736                 name_a = p->one->path;
5737                 name_b = p->two->path;
5738                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5739                 write_name_quoted(name_a, opt->file, inter_name_termination);
5740                 write_name_quoted(name_b, opt->file, line_termination);
5741         } else {
5742                 const char *name_a, *name_b;
5743                 name_a = p->one->mode ? p->one->path : p->two->path;
5744                 name_b = NULL;
5745                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5746                 write_name_quoted(name_a, opt->file, line_termination);
5747         }
5748 }
5749
5750 int diff_unmodified_pair(struct diff_filepair *p)
5751 {
5752         /* This function is written stricter than necessary to support
5753          * the currently implemented transformers, but the idea is to
5754          * let transformers to produce diff_filepairs any way they want,
5755          * and filter and clean them up here before producing the output.
5756          */
5757         struct diff_filespec *one = p->one, *two = p->two;
5758
5759         if (DIFF_PAIR_UNMERGED(p))
5760                 return 0; /* unmerged is interesting */
5761
5762         /* deletion, addition, mode or type change
5763          * and rename are all interesting.
5764          */
5765         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5766             DIFF_PAIR_MODE_CHANGED(p) ||
5767             strcmp(one->path, two->path))
5768                 return 0;
5769
5770         /* both are valid and point at the same path.  that is, we are
5771          * dealing with a change.
5772          */
5773         if (one->oid_valid && two->oid_valid &&
5774             oideq(&one->oid, &two->oid) &&
5775             !one->dirty_submodule && !two->dirty_submodule)
5776                 return 1; /* no change */
5777         if (!one->oid_valid && !two->oid_valid)
5778                 return 1; /* both look at the same file on the filesystem. */
5779         return 0;
5780 }
5781
5782 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5783 {
5784         if (diff_unmodified_pair(p))
5785                 return;
5786
5787         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5788             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5789                 return; /* no tree diffs in patch format */
5790
5791         run_diff(p, o);
5792 }
5793
5794 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5795                             struct diffstat_t *diffstat)
5796 {
5797         if (diff_unmodified_pair(p))
5798                 return;
5799
5800         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5801             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5802                 return; /* no useful stat for tree diffs */
5803
5804         run_diffstat(p, o, diffstat);
5805 }
5806
5807 static void diff_flush_checkdiff(struct diff_filepair *p,
5808                 struct diff_options *o)
5809 {
5810         if (diff_unmodified_pair(p))
5811                 return;
5812
5813         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5814             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5815                 return; /* nothing to check in tree diffs */
5816
5817         run_checkdiff(p, o);
5818 }
5819
5820 int diff_queue_is_empty(void)
5821 {
5822         struct diff_queue_struct *q = &diff_queued_diff;
5823         int i;
5824         for (i = 0; i < q->nr; i++)
5825                 if (!diff_unmodified_pair(q->queue[i]))
5826                         return 0;
5827         return 1;
5828 }
5829
5830 #if DIFF_DEBUG
5831 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5832 {
5833         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5834                 x, one ? one : "",
5835                 s->path,
5836                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5837                 s->mode,
5838                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5839         fprintf(stderr, "queue[%d] %s size %lu\n",
5840                 x, one ? one : "",
5841                 s->size);
5842 }
5843
5844 void diff_debug_filepair(const struct diff_filepair *p, int i)
5845 {
5846         diff_debug_filespec(p->one, i, "one");
5847         diff_debug_filespec(p->two, i, "two");
5848         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5849                 p->score, p->status ? p->status : '?',
5850                 p->one->rename_used, p->broken_pair);
5851 }
5852
5853 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5854 {
5855         int i;
5856         if (msg)
5857                 fprintf(stderr, "%s\n", msg);
5858         fprintf(stderr, "q->nr = %d\n", q->nr);
5859         for (i = 0; i < q->nr; i++) {
5860                 struct diff_filepair *p = q->queue[i];
5861                 diff_debug_filepair(p, i);
5862         }
5863 }
5864 #endif
5865
5866 static void diff_resolve_rename_copy(void)
5867 {
5868         int i;
5869         struct diff_filepair *p;
5870         struct diff_queue_struct *q = &diff_queued_diff;
5871
5872         diff_debug_queue("resolve-rename-copy", q);
5873
5874         for (i = 0; i < q->nr; i++) {
5875                 p = q->queue[i];
5876                 p->status = 0; /* undecided */
5877                 if (DIFF_PAIR_UNMERGED(p))
5878                         p->status = DIFF_STATUS_UNMERGED;
5879                 else if (!DIFF_FILE_VALID(p->one))
5880                         p->status = DIFF_STATUS_ADDED;
5881                 else if (!DIFF_FILE_VALID(p->two))
5882                         p->status = DIFF_STATUS_DELETED;
5883                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5884                         p->status = DIFF_STATUS_TYPE_CHANGED;
5885
5886                 /* from this point on, we are dealing with a pair
5887                  * whose both sides are valid and of the same type, i.e.
5888                  * either in-place edit or rename/copy edit.
5889                  */
5890                 else if (DIFF_PAIR_RENAME(p)) {
5891                         /*
5892                          * A rename might have re-connected a broken
5893                          * pair up, causing the pathnames to be the
5894                          * same again. If so, that's not a rename at
5895                          * all, just a modification..
5896                          *
5897                          * Otherwise, see if this source was used for
5898                          * multiple renames, in which case we decrement
5899                          * the count, and call it a copy.
5900                          */
5901                         if (!strcmp(p->one->path, p->two->path))
5902                                 p->status = DIFF_STATUS_MODIFIED;
5903                         else if (--p->one->rename_used > 0)
5904                                 p->status = DIFF_STATUS_COPIED;
5905                         else
5906                                 p->status = DIFF_STATUS_RENAMED;
5907                 }
5908                 else if (!oideq(&p->one->oid, &p->two->oid) ||
5909                          p->one->mode != p->two->mode ||
5910                          p->one->dirty_submodule ||
5911                          p->two->dirty_submodule ||
5912                          is_null_oid(&p->one->oid))
5913                         p->status = DIFF_STATUS_MODIFIED;
5914                 else {
5915                         /* This is a "no-change" entry and should not
5916                          * happen anymore, but prepare for broken callers.
5917                          */
5918                         error("feeding unmodified %s to diffcore",
5919                               p->one->path);
5920                         p->status = DIFF_STATUS_UNKNOWN;
5921                 }
5922         }
5923         diff_debug_queue("resolve-rename-copy done", q);
5924 }
5925
5926 static int check_pair_status(struct diff_filepair *p)
5927 {
5928         switch (p->status) {
5929         case DIFF_STATUS_UNKNOWN:
5930                 return 0;
5931         case 0:
5932                 die("internal error in diff-resolve-rename-copy");
5933         default:
5934                 return 1;
5935         }
5936 }
5937
5938 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5939 {
5940         int fmt = opt->output_format;
5941
5942         if (fmt & DIFF_FORMAT_CHECKDIFF)
5943                 diff_flush_checkdiff(p, opt);
5944         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5945                 diff_flush_raw(p, opt);
5946         else if (fmt & DIFF_FORMAT_NAME) {
5947                 const char *name_a, *name_b;
5948                 name_a = p->two->path;
5949                 name_b = NULL;
5950                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5951                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5952                 write_name_quoted(name_a, opt->file, opt->line_termination);
5953         }
5954 }
5955
5956 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5957 {
5958         struct strbuf sb = STRBUF_INIT;
5959         if (fs->mode)
5960                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5961         else
5962                 strbuf_addf(&sb, " %s ", newdelete);
5963
5964         quote_c_style(fs->path, &sb, NULL, 0);
5965         strbuf_addch(&sb, '\n');
5966         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5967                          sb.buf, sb.len, 0);
5968         strbuf_release(&sb);
5969 }
5970
5971 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5972                 int show_name)
5973 {
5974         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5975                 struct strbuf sb = STRBUF_INIT;
5976                 strbuf_addf(&sb, " mode change %06o => %06o",
5977                             p->one->mode, p->two->mode);
5978                 if (show_name) {
5979                         strbuf_addch(&sb, ' ');
5980                         quote_c_style(p->two->path, &sb, NULL, 0);
5981                 }
5982                 strbuf_addch(&sb, '\n');
5983                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5984                                  sb.buf, sb.len, 0);
5985                 strbuf_release(&sb);
5986         }
5987 }
5988
5989 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5990                 struct diff_filepair *p)
5991 {
5992         struct strbuf sb = STRBUF_INIT;
5993         struct strbuf names = STRBUF_INIT;
5994
5995         pprint_rename(&names, p->one->path, p->two->path);
5996         strbuf_addf(&sb, " %s %s (%d%%)\n",
5997                     renamecopy, names.buf, similarity_index(p));
5998         strbuf_release(&names);
5999         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
6000                                  sb.buf, sb.len, 0);
6001         show_mode_change(opt, p, 0);
6002         strbuf_release(&sb);
6003 }
6004
6005 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
6006 {
6007         switch(p->status) {
6008         case DIFF_STATUS_DELETED:
6009                 show_file_mode_name(opt, "delete", p->one);
6010                 break;
6011         case DIFF_STATUS_ADDED:
6012                 show_file_mode_name(opt, "create", p->two);
6013                 break;
6014         case DIFF_STATUS_COPIED:
6015                 show_rename_copy(opt, "copy", p);
6016                 break;
6017         case DIFF_STATUS_RENAMED:
6018                 show_rename_copy(opt, "rename", p);
6019                 break;
6020         default:
6021                 if (p->score) {
6022                         struct strbuf sb = STRBUF_INIT;
6023                         strbuf_addstr(&sb, " rewrite ");
6024                         quote_c_style(p->two->path, &sb, NULL, 0);
6025                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
6026                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
6027                                          sb.buf, sb.len, 0);
6028                         strbuf_release(&sb);
6029                 }
6030                 show_mode_change(opt, p, !p->score);
6031                 break;
6032         }
6033 }
6034
6035 struct patch_id_t {
6036         git_hash_ctx *ctx;
6037         int patchlen;
6038 };
6039
6040 static int remove_space(char *line, int len)
6041 {
6042         int i;
6043         char *dst = line;
6044         unsigned char c;
6045
6046         for (i = 0; i < len; i++)
6047                 if (!isspace((c = line[i])))
6048                         *dst++ = c;
6049
6050         return dst - line;
6051 }
6052
6053 void flush_one_hunk(struct object_id *result, git_hash_ctx *ctx)
6054 {
6055         unsigned char hash[GIT_MAX_RAWSZ];
6056         unsigned short carry = 0;
6057         int i;
6058
6059         the_hash_algo->final_fn(hash, ctx);
6060         the_hash_algo->init_fn(ctx);
6061         /* 20-byte sum, with carry */
6062         for (i = 0; i < the_hash_algo->rawsz; ++i) {
6063                 carry += result->hash[i] + hash[i];
6064                 result->hash[i] = carry;
6065                 carry >>= 8;
6066         }
6067 }
6068
6069 static void patch_id_consume(void *priv, char *line, unsigned long len)
6070 {
6071         struct patch_id_t *data = priv;
6072         int new_len;
6073
6074         if (len > 12 && starts_with(line, "\\ "))
6075                 return;
6076         new_len = remove_space(line, len);
6077
6078         the_hash_algo->update_fn(data->ctx, line, new_len);
6079         data->patchlen += new_len;
6080 }
6081
6082 static void patch_id_add_string(git_hash_ctx *ctx, const char *str)
6083 {
6084         the_hash_algo->update_fn(ctx, str, strlen(str));
6085 }
6086
6087 static void patch_id_add_mode(git_hash_ctx *ctx, unsigned mode)
6088 {
6089         /* large enough for 2^32 in octal */
6090         char buf[12];
6091         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
6092         the_hash_algo->update_fn(ctx, buf, len);
6093 }
6094
6095 /* returns 0 upon success, and writes result into oid */
6096 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only, int stable)
6097 {
6098         struct diff_queue_struct *q = &diff_queued_diff;
6099         int i;
6100         git_hash_ctx ctx;
6101         struct patch_id_t data;
6102
6103         the_hash_algo->init_fn(&ctx);
6104         memset(&data, 0, sizeof(struct patch_id_t));
6105         data.ctx = &ctx;
6106         oidclr(oid);
6107
6108         for (i = 0; i < q->nr; i++) {
6109                 xpparam_t xpp;
6110                 xdemitconf_t xecfg;
6111                 mmfile_t mf1, mf2;
6112                 struct diff_filepair *p = q->queue[i];
6113                 int len1, len2;
6114
6115                 memset(&xpp, 0, sizeof(xpp));
6116                 memset(&xecfg, 0, sizeof(xecfg));
6117                 if (p->status == 0)
6118                         return error("internal diff status error");
6119                 if (p->status == DIFF_STATUS_UNKNOWN)
6120                         continue;
6121                 if (diff_unmodified_pair(p))
6122                         continue;
6123                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
6124                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
6125                         continue;
6126                 if (DIFF_PAIR_UNMERGED(p))
6127                         continue;
6128
6129                 diff_fill_oid_info(p->one, options->repo->index);
6130                 diff_fill_oid_info(p->two, options->repo->index);
6131
6132                 len1 = remove_space(p->one->path, strlen(p->one->path));
6133                 len2 = remove_space(p->two->path, strlen(p->two->path));
6134                 patch_id_add_string(&ctx, "diff--git");
6135                 patch_id_add_string(&ctx, "a/");
6136                 the_hash_algo->update_fn(&ctx, p->one->path, len1);
6137                 patch_id_add_string(&ctx, "b/");
6138                 the_hash_algo->update_fn(&ctx, p->two->path, len2);
6139
6140                 if (p->one->mode == 0) {
6141                         patch_id_add_string(&ctx, "newfilemode");
6142                         patch_id_add_mode(&ctx, p->two->mode);
6143                         patch_id_add_string(&ctx, "---/dev/null");
6144                         patch_id_add_string(&ctx, "+++b/");
6145                         the_hash_algo->update_fn(&ctx, p->two->path, len2);
6146                 } else if (p->two->mode == 0) {
6147                         patch_id_add_string(&ctx, "deletedfilemode");
6148                         patch_id_add_mode(&ctx, p->one->mode);
6149                         patch_id_add_string(&ctx, "---a/");
6150                         the_hash_algo->update_fn(&ctx, p->one->path, len1);
6151                         patch_id_add_string(&ctx, "+++/dev/null");
6152                 } else {
6153                         patch_id_add_string(&ctx, "---a/");
6154                         the_hash_algo->update_fn(&ctx, p->one->path, len1);
6155                         patch_id_add_string(&ctx, "+++b/");
6156                         the_hash_algo->update_fn(&ctx, p->two->path, len2);
6157                 }
6158
6159                 if (diff_header_only)
6160                         continue;
6161
6162                 if (fill_mmfile(options->repo, &mf1, p->one) < 0 ||
6163                     fill_mmfile(options->repo, &mf2, p->two) < 0)
6164                         return error("unable to read files to diff");
6165
6166                 if (diff_filespec_is_binary(options->repo, p->one) ||
6167                     diff_filespec_is_binary(options->repo, p->two)) {
6168                         the_hash_algo->update_fn(&ctx, oid_to_hex(&p->one->oid),
6169                                         the_hash_algo->hexsz);
6170                         the_hash_algo->update_fn(&ctx, oid_to_hex(&p->two->oid),
6171                                         the_hash_algo->hexsz);
6172                         continue;
6173                 }
6174
6175                 xpp.flags = 0;
6176                 xecfg.ctxlen = 3;
6177                 xecfg.flags = 0;
6178                 if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
6179                                   patch_id_consume, &data, &xpp, &xecfg))
6180                         return error("unable to generate patch-id diff for %s",
6181                                      p->one->path);
6182
6183                 if (stable)
6184                         flush_one_hunk(oid, &ctx);
6185         }
6186
6187         if (!stable)
6188                 the_hash_algo->final_fn(oid->hash, &ctx);
6189
6190         return 0;
6191 }
6192
6193 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only, int stable)
6194 {
6195         struct diff_queue_struct *q = &diff_queued_diff;
6196         int i;
6197         int result = diff_get_patch_id(options, oid, diff_header_only, stable);
6198
6199         for (i = 0; i < q->nr; i++)
6200                 diff_free_filepair(q->queue[i]);
6201
6202         free(q->queue);
6203         DIFF_QUEUE_CLEAR(q);
6204
6205         return result;
6206 }
6207
6208 static int is_summary_empty(const struct diff_queue_struct *q)
6209 {
6210         int i;
6211
6212         for (i = 0; i < q->nr; i++) {
6213                 const struct diff_filepair *p = q->queue[i];
6214
6215                 switch (p->status) {
6216                 case DIFF_STATUS_DELETED:
6217                 case DIFF_STATUS_ADDED:
6218                 case DIFF_STATUS_COPIED:
6219                 case DIFF_STATUS_RENAMED:
6220                         return 0;
6221                 default:
6222                         if (p->score)
6223                                 return 0;
6224                         if (p->one->mode && p->two->mode &&
6225                             p->one->mode != p->two->mode)
6226                                 return 0;
6227                         break;
6228                 }
6229         }
6230         return 1;
6231 }
6232
6233 static const char rename_limit_warning[] =
6234 N_("inexact rename detection was skipped due to too many files.");
6235
6236 static const char degrade_cc_to_c_warning[] =
6237 N_("only found copies from modified paths due to too many files.");
6238
6239 static const char rename_limit_advice[] =
6240 N_("you may want to set your %s variable to at least "
6241    "%d and retry the command.");
6242
6243 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
6244 {
6245         fflush(stdout);
6246         if (degraded_cc)
6247                 warning(_(degrade_cc_to_c_warning));
6248         else if (needed)
6249                 warning(_(rename_limit_warning));
6250         else
6251                 return;
6252         if (0 < needed)
6253                 warning(_(rename_limit_advice), varname, needed);
6254 }
6255
6256 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
6257 {
6258         int i;
6259         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
6260         struct diff_queue_struct *q = &diff_queued_diff;
6261
6262         if (WSEH_NEW & WS_RULE_MASK)
6263                 BUG("WS rules bit mask overlaps with diff symbol flags");
6264
6265         if (o->color_moved)
6266                 o->emitted_symbols = &esm;
6267
6268         for (i = 0; i < q->nr; i++) {
6269                 struct diff_filepair *p = q->queue[i];
6270                 if (check_pair_status(p))
6271                         diff_flush_patch(p, o);
6272         }
6273
6274         if (o->emitted_symbols) {
6275                 if (o->color_moved) {
6276                         struct hashmap add_lines, del_lines;
6277
6278                         if (o->color_moved_ws_handling &
6279                             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
6280                                 o->color_moved_ws_handling |= XDF_IGNORE_WHITESPACE;
6281
6282                         hashmap_init(&del_lines, moved_entry_cmp, o, 0);
6283                         hashmap_init(&add_lines, moved_entry_cmp, o, 0);
6284
6285                         add_lines_to_move_detection(o, &add_lines, &del_lines);
6286                         mark_color_as_moved(o, &add_lines, &del_lines);
6287                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
6288                                 dim_moved_lines(o);
6289
6290                         hashmap_free_entries(&add_lines, struct moved_entry,
6291                                                 ent);
6292                         hashmap_free_entries(&del_lines, struct moved_entry,
6293                                                 ent);
6294                 }
6295
6296                 for (i = 0; i < esm.nr; i++)
6297                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
6298
6299                 for (i = 0; i < esm.nr; i++)
6300                         free((void *)esm.buf[i].line);
6301                 esm.nr = 0;
6302
6303                 o->emitted_symbols = NULL;
6304         }
6305 }
6306
6307 void diff_flush(struct diff_options *options)
6308 {
6309         struct diff_queue_struct *q = &diff_queued_diff;
6310         int i, output_format = options->output_format;
6311         int separator = 0;
6312         int dirstat_by_line = 0;
6313
6314         /*
6315          * Order: raw, stat, summary, patch
6316          * or:    name/name-status/checkdiff (other bits clear)
6317          */
6318         if (!q->nr)
6319                 goto free_queue;
6320
6321         if (output_format & (DIFF_FORMAT_RAW |
6322                              DIFF_FORMAT_NAME |
6323                              DIFF_FORMAT_NAME_STATUS |
6324                              DIFF_FORMAT_CHECKDIFF)) {
6325                 for (i = 0; i < q->nr; i++) {
6326                         struct diff_filepair *p = q->queue[i];
6327                         if (check_pair_status(p))
6328                                 flush_one_pair(p, options);
6329                 }
6330                 separator++;
6331         }
6332
6333         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
6334                 dirstat_by_line = 1;
6335
6336         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
6337             dirstat_by_line) {
6338                 struct diffstat_t diffstat;
6339
6340                 compute_diffstat(options, &diffstat, q);
6341                 if (output_format & DIFF_FORMAT_NUMSTAT)
6342                         show_numstat(&diffstat, options);
6343                 if (output_format & DIFF_FORMAT_DIFFSTAT)
6344                         show_stats(&diffstat, options);
6345                 if (output_format & DIFF_FORMAT_SHORTSTAT)
6346                         show_shortstats(&diffstat, options);
6347                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
6348                         show_dirstat_by_line(&diffstat, options);
6349                 free_diffstat_info(&diffstat);
6350                 separator++;
6351         }
6352         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
6353                 show_dirstat(options);
6354
6355         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
6356                 for (i = 0; i < q->nr; i++) {
6357                         diff_summary(options, q->queue[i]);
6358                 }
6359                 separator++;
6360         }
6361
6362         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
6363             options->flags.exit_with_status &&
6364             options->flags.diff_from_contents) {
6365                 /*
6366                  * run diff_flush_patch for the exit status. setting
6367                  * options->file to /dev/null should be safe, because we
6368                  * aren't supposed to produce any output anyway.
6369                  */
6370                 if (options->close_file)
6371                         fclose(options->file);
6372                 options->file = xfopen("/dev/null", "w");
6373                 options->close_file = 1;
6374                 options->color_moved = 0;
6375                 for (i = 0; i < q->nr; i++) {
6376                         struct diff_filepair *p = q->queue[i];
6377                         if (check_pair_status(p))
6378                                 diff_flush_patch(p, options);
6379                         if (options->found_changes)
6380                                 break;
6381                 }
6382         }
6383
6384         if (output_format & DIFF_FORMAT_PATCH) {
6385                 if (separator) {
6386                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
6387                         if (options->stat_sep)
6388                                 /* attach patch instead of inline */
6389                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
6390                                                  NULL, 0, 0);
6391                 }
6392
6393                 diff_flush_patch_all_file_pairs(options);
6394         }
6395
6396         if (output_format & DIFF_FORMAT_CALLBACK)
6397                 options->format_callback(q, options, options->format_callback_data);
6398
6399         for (i = 0; i < q->nr; i++)
6400                 diff_free_filepair(q->queue[i]);
6401 free_queue:
6402         free(q->queue);
6403         DIFF_QUEUE_CLEAR(q);
6404         if (options->close_file)
6405                 fclose(options->file);
6406
6407         /*
6408          * Report the content-level differences with HAS_CHANGES;
6409          * diff_addremove/diff_change does not set the bit when
6410          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
6411          */
6412         if (options->flags.diff_from_contents) {
6413                 if (options->found_changes)
6414                         options->flags.has_changes = 1;
6415                 else
6416                         options->flags.has_changes = 0;
6417         }
6418 }
6419
6420 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
6421 {
6422         return (((p->status == DIFF_STATUS_MODIFIED) &&
6423                  ((p->score &&
6424                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
6425                   (!p->score &&
6426                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
6427                 ((p->status != DIFF_STATUS_MODIFIED) &&
6428                  filter_bit_tst(p->status, options)));
6429 }
6430
6431 static void diffcore_apply_filter(struct diff_options *options)
6432 {
6433         int i;
6434         struct diff_queue_struct *q = &diff_queued_diff;
6435         struct diff_queue_struct outq;
6436
6437         DIFF_QUEUE_CLEAR(&outq);
6438
6439         if (!options->filter)
6440                 return;
6441
6442         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
6443                 int found;
6444                 for (i = found = 0; !found && i < q->nr; i++) {
6445                         if (match_filter(options, q->queue[i]))
6446                                 found++;
6447                 }
6448                 if (found)
6449                         return;
6450
6451                 /* otherwise we will clear the whole queue
6452                  * by copying the empty outq at the end of this
6453                  * function, but first clear the current entries
6454                  * in the queue.
6455                  */
6456                 for (i = 0; i < q->nr; i++)
6457                         diff_free_filepair(q->queue[i]);
6458         }
6459         else {
6460                 /* Only the matching ones */
6461                 for (i = 0; i < q->nr; i++) {
6462                         struct diff_filepair *p = q->queue[i];
6463                         if (match_filter(options, p))
6464                                 diff_q(&outq, p);
6465                         else
6466                                 diff_free_filepair(p);
6467                 }
6468         }
6469         free(q->queue);
6470         *q = outq;
6471 }
6472
6473 /* Check whether two filespecs with the same mode and size are identical */
6474 static int diff_filespec_is_identical(struct repository *r,
6475                                       struct diff_filespec *one,
6476                                       struct diff_filespec *two)
6477 {
6478         if (S_ISGITLINK(one->mode))
6479                 return 0;
6480         if (diff_populate_filespec(r, one, NULL))
6481                 return 0;
6482         if (diff_populate_filespec(r, two, NULL))
6483                 return 0;
6484         return !memcmp(one->data, two->data, one->size);
6485 }
6486
6487 static int diff_filespec_check_stat_unmatch(struct repository *r,
6488                                             struct diff_filepair *p)
6489 {
6490         struct diff_populate_filespec_options dpf_options = {
6491                 .check_size_only = 1,
6492                 .missing_object_cb = diff_queued_diff_prefetch,
6493                 .missing_object_data = r,
6494         };
6495
6496         if (p->done_skip_stat_unmatch)
6497                 return p->skip_stat_unmatch_result;
6498
6499         p->done_skip_stat_unmatch = 1;
6500         p->skip_stat_unmatch_result = 0;
6501         /*
6502          * 1. Entries that come from stat info dirtiness
6503          *    always have both sides (iow, not create/delete),
6504          *    one side of the object name is unknown, with
6505          *    the same mode and size.  Keep the ones that
6506          *    do not match these criteria.  They have real
6507          *    differences.
6508          *
6509          * 2. At this point, the file is known to be modified,
6510          *    with the same mode and size, and the object
6511          *    name of one side is unknown.  Need to inspect
6512          *    the identical contents.
6513          */
6514         if (!DIFF_FILE_VALID(p->one) || /* (1) */
6515             !DIFF_FILE_VALID(p->two) ||
6516             (p->one->oid_valid && p->two->oid_valid) ||
6517             (p->one->mode != p->two->mode) ||
6518             diff_populate_filespec(r, p->one, &dpf_options) ||
6519             diff_populate_filespec(r, p->two, &dpf_options) ||
6520             (p->one->size != p->two->size) ||
6521             !diff_filespec_is_identical(r, p->one, p->two)) /* (2) */
6522                 p->skip_stat_unmatch_result = 1;
6523         return p->skip_stat_unmatch_result;
6524 }
6525
6526 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
6527 {
6528         int i;
6529         struct diff_queue_struct *q = &diff_queued_diff;
6530         struct diff_queue_struct outq;
6531         DIFF_QUEUE_CLEAR(&outq);
6532
6533         for (i = 0; i < q->nr; i++) {
6534                 struct diff_filepair *p = q->queue[i];
6535
6536                 if (diff_filespec_check_stat_unmatch(diffopt->repo, p))
6537                         diff_q(&outq, p);
6538                 else {
6539                         /*
6540                          * The caller can subtract 1 from skip_stat_unmatch
6541                          * to determine how many paths were dirty only
6542                          * due to stat info mismatch.
6543                          */
6544                         if (!diffopt->flags.no_index)
6545                                 diffopt->skip_stat_unmatch++;
6546                         diff_free_filepair(p);
6547                 }
6548         }
6549         free(q->queue);
6550         *q = outq;
6551 }
6552
6553 static int diffnamecmp(const void *a_, const void *b_)
6554 {
6555         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
6556         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
6557         const char *name_a, *name_b;
6558
6559         name_a = a->one ? a->one->path : a->two->path;
6560         name_b = b->one ? b->one->path : b->two->path;
6561         return strcmp(name_a, name_b);
6562 }
6563
6564 void diffcore_fix_diff_index(void)
6565 {
6566         struct diff_queue_struct *q = &diff_queued_diff;
6567         QSORT(q->queue, q->nr, diffnamecmp);
6568 }
6569
6570 void diff_add_if_missing(struct repository *r,
6571                          struct oid_array *to_fetch,
6572                          const struct diff_filespec *filespec)
6573 {
6574         if (filespec && filespec->oid_valid &&
6575             !S_ISGITLINK(filespec->mode) &&
6576             oid_object_info_extended(r, &filespec->oid, NULL,
6577                                      OBJECT_INFO_FOR_PREFETCH))
6578                 oid_array_append(to_fetch, &filespec->oid);
6579 }
6580
6581 void diff_queued_diff_prefetch(void *repository)
6582 {
6583         struct repository *repo = repository;
6584         int i;
6585         struct diff_queue_struct *q = &diff_queued_diff;
6586         struct oid_array to_fetch = OID_ARRAY_INIT;
6587
6588         for (i = 0; i < q->nr; i++) {
6589                 struct diff_filepair *p = q->queue[i];
6590                 diff_add_if_missing(repo, &to_fetch, p->one);
6591                 diff_add_if_missing(repo, &to_fetch, p->two);
6592         }
6593
6594         /*
6595          * NEEDSWORK: Consider deduplicating the OIDs sent.
6596          */
6597         promisor_remote_get_direct(repo, to_fetch.oid, to_fetch.nr);
6598
6599         oid_array_clear(&to_fetch);
6600 }
6601
6602 void diffcore_std(struct diff_options *options)
6603 {
6604         int output_formats_to_prefetch = DIFF_FORMAT_DIFFSTAT |
6605                 DIFF_FORMAT_NUMSTAT |
6606                 DIFF_FORMAT_PATCH |
6607                 DIFF_FORMAT_SHORTSTAT |
6608                 DIFF_FORMAT_DIRSTAT;
6609
6610         /*
6611          * Check if the user requested a blob-data-requiring diff output and/or
6612          * break-rewrite detection (which requires blob data). If yes, prefetch
6613          * the diff pairs.
6614          *
6615          * If no prefetching occurs, diffcore_rename() will prefetch if it
6616          * decides that it needs inexact rename detection.
6617          */
6618         if (options->repo == the_repository && has_promisor_remote() &&
6619             (options->output_format & output_formats_to_prefetch ||
6620              options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
6621                 diff_queued_diff_prefetch(options->repo);
6622
6623         /* NOTE please keep the following in sync with diff_tree_combined() */
6624         if (options->skip_stat_unmatch)
6625                 diffcore_skip_stat_unmatch(options);
6626         if (!options->found_follow) {
6627                 /* See try_to_follow_renames() in tree-diff.c */
6628                 if (options->break_opt != -1)
6629                         diffcore_break(options->repo,
6630                                        options->break_opt);
6631                 if (options->detect_rename)
6632                         diffcore_rename(options);
6633                 if (options->break_opt != -1)
6634                         diffcore_merge_broken();
6635         }
6636         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
6637                 diffcore_pickaxe(options);
6638         if (options->orderfile)
6639                 diffcore_order(options->orderfile);
6640         if (!options->found_follow)
6641                 /* See try_to_follow_renames() in tree-diff.c */
6642                 diff_resolve_rename_copy();
6643         diffcore_apply_filter(options);
6644
6645         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
6646                 options->flags.has_changes = 1;
6647         else
6648                 options->flags.has_changes = 0;
6649
6650         options->found_follow = 0;
6651 }
6652
6653 int diff_result_code(struct diff_options *opt, int status)
6654 {
6655         int result = 0;
6656
6657         diff_warn_rename_limit("diff.renameLimit",
6658                                opt->needed_rename_limit,
6659                                opt->degraded_cc_to_c);
6660         if (!opt->flags.exit_with_status &&
6661             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
6662                 return status;
6663         if (opt->flags.exit_with_status &&
6664             opt->flags.has_changes)
6665                 result |= 01;
6666         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
6667             opt->flags.check_failed)
6668                 result |= 02;
6669         return result;
6670 }
6671
6672 int diff_can_quit_early(struct diff_options *opt)
6673 {
6674         return (opt->flags.quick &&
6675                 !opt->filter &&
6676                 opt->flags.has_changes);
6677 }
6678
6679 /*
6680  * Shall changes to this submodule be ignored?
6681  *
6682  * Submodule changes can be configured to be ignored separately for each path,
6683  * but that configuration can be overridden from the command line.
6684  */
6685 static int is_submodule_ignored(const char *path, struct diff_options *options)
6686 {
6687         int ignored = 0;
6688         struct diff_flags orig_flags = options->flags;
6689         if (!options->flags.override_submodule_config)
6690                 set_diffopt_flags_from_submodule_config(options, path);
6691         if (options->flags.ignore_submodules)
6692                 ignored = 1;
6693         options->flags = orig_flags;
6694         return ignored;
6695 }
6696
6697 void compute_diffstat(struct diff_options *options,
6698                       struct diffstat_t *diffstat,
6699                       struct diff_queue_struct *q)
6700 {
6701         int i;
6702
6703         memset(diffstat, 0, sizeof(struct diffstat_t));
6704         for (i = 0; i < q->nr; i++) {
6705                 struct diff_filepair *p = q->queue[i];
6706                 if (check_pair_status(p))
6707                         diff_flush_stat(p, options, diffstat);
6708         }
6709 }
6710
6711 void diff_addremove(struct diff_options *options,
6712                     int addremove, unsigned mode,
6713                     const struct object_id *oid,
6714                     int oid_valid,
6715                     const char *concatpath, unsigned dirty_submodule)
6716 {
6717         struct diff_filespec *one, *two;
6718
6719         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
6720                 return;
6721
6722         /* This may look odd, but it is a preparation for
6723          * feeding "there are unchanged files which should
6724          * not produce diffs, but when you are doing copy
6725          * detection you would need them, so here they are"
6726          * entries to the diff-core.  They will be prefixed
6727          * with something like '=' or '*' (I haven't decided
6728          * which but should not make any difference).
6729          * Feeding the same new and old to diff_change()
6730          * also has the same effect.
6731          * Before the final output happens, they are pruned after
6732          * merged into rename/copy pairs as appropriate.
6733          */
6734         if (options->flags.reverse_diff)
6735                 addremove = (addremove == '+' ? '-' :
6736                              addremove == '-' ? '+' : addremove);
6737
6738         if (options->prefix &&
6739             strncmp(concatpath, options->prefix, options->prefix_length))
6740                 return;
6741
6742         one = alloc_filespec(concatpath);
6743         two = alloc_filespec(concatpath);
6744
6745         if (addremove != '+')
6746                 fill_filespec(one, oid, oid_valid, mode);
6747         if (addremove != '-') {
6748                 fill_filespec(two, oid, oid_valid, mode);
6749                 two->dirty_submodule = dirty_submodule;
6750         }
6751
6752         diff_queue(&diff_queued_diff, one, two);
6753         if (!options->flags.diff_from_contents)
6754                 options->flags.has_changes = 1;
6755 }
6756
6757 void diff_change(struct diff_options *options,
6758                  unsigned old_mode, unsigned new_mode,
6759                  const struct object_id *old_oid,
6760                  const struct object_id *new_oid,
6761                  int old_oid_valid, int new_oid_valid,
6762                  const char *concatpath,
6763                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
6764 {
6765         struct diff_filespec *one, *two;
6766         struct diff_filepair *p;
6767
6768         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
6769             is_submodule_ignored(concatpath, options))
6770                 return;
6771
6772         if (options->flags.reverse_diff) {
6773                 SWAP(old_mode, new_mode);
6774                 SWAP(old_oid, new_oid);
6775                 SWAP(old_oid_valid, new_oid_valid);
6776                 SWAP(old_dirty_submodule, new_dirty_submodule);
6777         }
6778
6779         if (options->prefix &&
6780             strncmp(concatpath, options->prefix, options->prefix_length))
6781                 return;
6782
6783         one = alloc_filespec(concatpath);
6784         two = alloc_filespec(concatpath);
6785         fill_filespec(one, old_oid, old_oid_valid, old_mode);
6786         fill_filespec(two, new_oid, new_oid_valid, new_mode);
6787         one->dirty_submodule = old_dirty_submodule;
6788         two->dirty_submodule = new_dirty_submodule;
6789         p = diff_queue(&diff_queued_diff, one, two);
6790
6791         if (options->flags.diff_from_contents)
6792                 return;
6793
6794         if (options->flags.quick && options->skip_stat_unmatch &&
6795             !diff_filespec_check_stat_unmatch(options->repo, p)) {
6796                 diff_free_filespec_data(p->one);
6797                 diff_free_filespec_data(p->two);
6798                 return;
6799         }
6800
6801         options->flags.has_changes = 1;
6802 }
6803
6804 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
6805 {
6806         struct diff_filepair *pair;
6807         struct diff_filespec *one, *two;
6808
6809         if (options->prefix &&
6810             strncmp(path, options->prefix, options->prefix_length))
6811                 return NULL;
6812
6813         one = alloc_filespec(path);
6814         two = alloc_filespec(path);
6815         pair = diff_queue(&diff_queued_diff, one, two);
6816         pair->is_unmerged = 1;
6817         return pair;
6818 }
6819
6820 static char *run_textconv(struct repository *r,
6821                           const char *pgm,
6822                           struct diff_filespec *spec,
6823                           size_t *outsize)
6824 {
6825         struct diff_tempfile *temp;
6826         const char *argv[3];
6827         const char **arg = argv;
6828         struct child_process child = CHILD_PROCESS_INIT;
6829         struct strbuf buf = STRBUF_INIT;
6830         int err = 0;
6831
6832         temp = prepare_temp_file(r, spec->path, spec);
6833         *arg++ = pgm;
6834         *arg++ = temp->name;
6835         *arg = NULL;
6836
6837         child.use_shell = 1;
6838         child.argv = argv;
6839         child.out = -1;
6840         if (start_command(&child)) {
6841                 remove_tempfile();
6842                 return NULL;
6843         }
6844
6845         if (strbuf_read(&buf, child.out, 0) < 0)
6846                 err = error("error reading from textconv command '%s'", pgm);
6847         close(child.out);
6848
6849         if (finish_command(&child) || err) {
6850                 strbuf_release(&buf);
6851                 remove_tempfile();
6852                 return NULL;
6853         }
6854         remove_tempfile();
6855
6856         return strbuf_detach(&buf, outsize);
6857 }
6858
6859 size_t fill_textconv(struct repository *r,
6860                      struct userdiff_driver *driver,
6861                      struct diff_filespec *df,
6862                      char **outbuf)
6863 {
6864         size_t size;
6865
6866         if (!driver) {
6867                 if (!DIFF_FILE_VALID(df)) {
6868                         *outbuf = "";
6869                         return 0;
6870                 }
6871                 if (diff_populate_filespec(r, df, NULL))
6872                         die("unable to read files to diff");
6873                 *outbuf = df->data;
6874                 return df->size;
6875         }
6876
6877         if (!driver->textconv)
6878                 BUG("fill_textconv called with non-textconv driver");
6879
6880         if (driver->textconv_cache && df->oid_valid) {
6881                 *outbuf = notes_cache_get(driver->textconv_cache,
6882                                           &df->oid,
6883                                           &size);
6884                 if (*outbuf)
6885                         return size;
6886         }
6887
6888         *outbuf = run_textconv(r, driver->textconv, df, &size);
6889         if (!*outbuf)
6890                 die("unable to read files to diff");
6891
6892         if (driver->textconv_cache && df->oid_valid) {
6893                 /* ignore errors, as we might be in a readonly repository */
6894                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6895                                 size);
6896                 /*
6897                  * we could save up changes and flush them all at the end,
6898                  * but we would need an extra call after all diffing is done.
6899                  * Since generating a cache entry is the slow path anyway,
6900                  * this extra overhead probably isn't a big deal.
6901                  */
6902                 notes_cache_write(driver->textconv_cache);
6903         }
6904
6905         return size;
6906 }
6907
6908 int textconv_object(struct repository *r,
6909                     const char *path,
6910                     unsigned mode,
6911                     const struct object_id *oid,
6912                     int oid_valid,
6913                     char **buf,
6914                     unsigned long *buf_size)
6915 {
6916         struct diff_filespec *df;
6917         struct userdiff_driver *textconv;
6918
6919         df = alloc_filespec(path);
6920         fill_filespec(df, oid, oid_valid, mode);
6921         textconv = get_textconv(r, df);
6922         if (!textconv) {
6923                 free_filespec(df);
6924                 return 0;
6925         }
6926
6927         *buf_size = fill_textconv(r, textconv, df, buf);
6928         free_filespec(df);
6929         return 1;
6930 }
6931
6932 void setup_diff_pager(struct diff_options *opt)
6933 {
6934         /*
6935          * If the user asked for our exit code, then either they want --quiet
6936          * or --exit-code. We should definitely not bother with a pager in the
6937          * former case, as we will generate no output. Since we still properly
6938          * report our exit code even when a pager is run, we _could_ run a
6939          * pager with --exit-code. But since we have not done so historically,
6940          * and because it is easy to find people oneline advising "git diff
6941          * --exit-code" in hooks and other scripts, we do not do so.
6942          */
6943         if (!opt->flags.exit_with_status &&
6944             check_pager_config("diff") != 0)
6945                 setup_pager();
6946 }