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 "argv-array.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_stat_graph_width;
  52 static int diff_dirstat_permille_default = 30;
  53 static struct diff_options default_diff_options;
  54 static long diff_algorithm;
  55 static unsigned ws_error_highlight_default = WSEH_NEW;
  56
  57 static char diff_colors[][COLOR_MAXLEN] = {
  58         GIT_COLOR_RESET,
  59         GIT_COLOR_NORMAL,       /* CONTEXT */
  60         GIT_COLOR_BOLD,         /* METAINFO */
  61         GIT_COLOR_CYAN,         /* FRAGINFO */
  62         GIT_COLOR_RED,          /* OLD */
  63         GIT_COLOR_GREEN,        /* NEW */
  64         GIT_COLOR_YELLOW,       /* COMMIT */
  65         GIT_COLOR_BG_RED,       /* WHITESPACE */
  66         GIT_COLOR_NORMAL,       /* FUNCINFO */
  67         GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  68         GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  69         GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  70         GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  71         GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  72         GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  73         GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  74         GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  75         GIT_COLOR_FAINT,        /* CONTEXT_DIM */
  76         GIT_COLOR_FAINT_RED,    /* OLD_DIM */
  77         GIT_COLOR_FAINT_GREEN,  /* NEW_DIM */
  78         GIT_COLOR_BOLD,         /* CONTEXT_BOLD */
  79         GIT_COLOR_BOLD_RED,     /* OLD_BOLD */
  80         GIT_COLOR_BOLD_GREEN,   /* NEW_BOLD */
  81 };
  82
  83 static const char *color_diff_slots[] = {
  84         [DIFF_CONTEXT]                = "context",
  85         [DIFF_METAINFO]               = "meta",
  86         [DIFF_FRAGINFO]               = "frag",
  87         [DIFF_FILE_OLD]               = "old",
  88         [DIFF_FILE_NEW]               = "new",
  89         [DIFF_COMMIT]                 = "commit",
  90         [DIFF_WHITESPACE]             = "whitespace",
  91         [DIFF_FUNCINFO]               = "func",
  92         [DIFF_FILE_OLD_MOVED]         = "oldMoved",
  93         [DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
  94         [DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
  95         [DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
  96         [DIFF_FILE_NEW_MOVED]         = "newMoved",
  97         [DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
  98         [DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
  99         [DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
 100         [DIFF_CONTEXT_DIM]            = "contextDimmed",
 101         [DIFF_FILE_OLD_DIM]           = "oldDimmed",
 102         [DIFF_FILE_NEW_DIM]           = "newDimmed",
 103         [DIFF_CONTEXT_BOLD]           = "contextBold",
 104         [DIFF_FILE_OLD_BOLD]          = "oldBold",
 105         [DIFF_FILE_NEW_BOLD]          = "newBold",
 106 };
 107
 108 define_list_config_array_extra(color_diff_slots, {"plain"});
 109
 110 static int parse_diff_color_slot(const char *var)
 111 {
 112         if (!strcasecmp(var, "plain"))
 113                 return DIFF_CONTEXT;
 114         return LOOKUP_CONFIG(color_diff_slots, var);
 115 }
 116
 117 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 118                                 struct strbuf *errmsg)
 119 {
 120         char *params_copy = xstrdup(params_string);
 121         struct string_list params = STRING_LIST_INIT_NODUP;
 122         int ret = 0;
 123         int i;
 124
 125         if (*params_copy)
 126                 string_list_split_in_place(&params, params_copy, ',', -1);
 127         for (i = 0; i < params.nr; i++) {
 128                 const char *p = params.items[i].string;
 129                 if (!strcmp(p, "changes")) {
 130                         options->flags.dirstat_by_line = 0;
 131                         options->flags.dirstat_by_file = 0;
 132                 } else if (!strcmp(p, "lines")) {
 133                         options->flags.dirstat_by_line = 1;
 134                         options->flags.dirstat_by_file = 0;
 135                 } else if (!strcmp(p, "files")) {
 136                         options->flags.dirstat_by_line = 0;
 137                         options->flags.dirstat_by_file = 1;
 138                 } else if (!strcmp(p, "noncumulative")) {
 139                         options->flags.dirstat_cumulative = 0;
 140                 } else if (!strcmp(p, "cumulative")) {
 141                         options->flags.dirstat_cumulative = 1;
 142                 } else if (isdigit(*p)) {
 143                         char *end;
 144                         int permille = strtoul(p, &end, 10) * 10;
 145                         if (*end == '.' && isdigit(*++end)) {
 146                                 /* only use first digit */
 147                                 permille += *end - '0';
 148                                 /* .. and ignore any further digits */
 149                                 while (isdigit(*++end))
 150                                         ; /* nothing */
 151                         }
 152                         if (!*end)
 153                                 options->dirstat_permille = permille;
 154                         else {
 155                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 156                                             p);
 157                                 ret++;
 158                         }
 159                 } else {
 160                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 161                         ret++;
 162                 }
 163
 164         }
 165         string_list_clear(&params, 0);
 166         free(params_copy);
 167         return ret;
 168 }
 169
 170 static int parse_submodule_params(struct diff_options *options, const char *value)
 171 {
 172         if (!strcmp(value, "log"))
 173                 options->submodule_format = DIFF_SUBMODULE_LOG;
 174         else if (!strcmp(value, "short"))
 175                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 176         else if (!strcmp(value, "diff"))
 177                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 178         /*
 179          * Please update $__git_diff_submodule_formats in
 180          * git-completion.bash when you add new formats.
 181          */
 182         else
 183                 return -1;
 184         return 0;
 185 }
 186
 187 int git_config_rename(const char *var, const char *value)
 188 {
 189         if (!value)
 190                 return DIFF_DETECT_RENAME;
 191         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 192                 return  DIFF_DETECT_COPY;
 193         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 194 }
 195
 196 long parse_algorithm_value(const char *value)
 197 {
 198         if (!value)
 199                 return -1;
 200         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 201                 return 0;
 202         else if (!strcasecmp(value, "minimal"))
 203                 return XDF_NEED_MINIMAL;
 204         else if (!strcasecmp(value, "patience"))
 205                 return XDF_PATIENCE_DIFF;
 206         else if (!strcasecmp(value, "histogram"))
 207                 return XDF_HISTOGRAM_DIFF;
 208         /*
 209          * Please update $__git_diff_algorithms in git-completion.bash
 210          * when you add new algorithms.
 211          */
 212         return -1;
 213 }
 214
 215 static int parse_one_token(const char **arg, const char *token)
 216 {
 217         const char *rest;
 218         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 219                 *arg = rest;
 220                 return 1;
 221         }
 222         return 0;
 223 }
 224
 225 static int parse_ws_error_highlight(const char *arg)
 226 {
 227         const char *orig_arg = arg;
 228         unsigned val = 0;
 229
 230         while (*arg) {
 231                 if (parse_one_token(&arg, "none"))
 232                         val = 0;
 233                 else if (parse_one_token(&arg, "default"))
 234                         val = WSEH_NEW;
 235                 else if (parse_one_token(&arg, "all"))
 236                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 237                 else if (parse_one_token(&arg, "new"))
 238                         val |= WSEH_NEW;
 239                 else if (parse_one_token(&arg, "old"))
 240                         val |= WSEH_OLD;
 241                 else if (parse_one_token(&arg, "context"))
 242                         val |= WSEH_CONTEXT;
 243                 else {
 244                         return -1 - (int)(arg - orig_arg);
 245                 }
 246                 if (*arg)
 247                         arg++;
 248         }
 249         return val;
 250 }
 251
 252 /*
 253  * These are to give UI layer defaults.
 254  * The core-level commands such as git-diff-files should
 255  * never be affected by the setting of diff.renames
 256  * the user happens to have in the configuration file.
 257  */
 258 void init_diff_ui_defaults(void)
 259 {
 260         diff_detect_rename_default = DIFF_DETECT_RENAME;
 261 }
 262
 263 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 264 {
 265         if (!strcmp(var, "diff.indentheuristic"))
 266                 diff_indent_heuristic = git_config_bool(var, value);
 267         return 0;
 268 }
 269
 270 static int parse_color_moved(const char *arg)
 271 {
 272         switch (git_parse_maybe_bool(arg)) {
 273         case 0:
 274                 return COLOR_MOVED_NO;
 275         case 1:
 276                 return COLOR_MOVED_DEFAULT;
 277         default:
 278                 break;
 279         }
 280
 281         if (!strcmp(arg, "no"))
 282                 return COLOR_MOVED_NO;
 283         else if (!strcmp(arg, "plain"))
 284                 return COLOR_MOVED_PLAIN;
 285         else if (!strcmp(arg, "blocks"))
 286                 return COLOR_MOVED_BLOCKS;
 287         else if (!strcmp(arg, "zebra"))
 288                 return COLOR_MOVED_ZEBRA;
 289         else if (!strcmp(arg, "default"))
 290                 return COLOR_MOVED_DEFAULT;
 291         else if (!strcmp(arg, "dimmed-zebra"))
 292                 return COLOR_MOVED_ZEBRA_DIM;
 293         else if (!strcmp(arg, "dimmed_zebra"))
 294                 return COLOR_MOVED_ZEBRA_DIM;
 295         else
 296                 return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed-zebra', 'plain'"));
 297 }
 298
 299 static unsigned parse_color_moved_ws(const char *arg)
 300 {
 301         int ret = 0;
 302         struct string_list l = STRING_LIST_INIT_DUP;
 303         struct string_list_item *i;
 304
 305         string_list_split(&l, arg, ',', -1);
 306
 307         for_each_string_list_item(i, &l) {
 308                 struct strbuf sb = STRBUF_INIT;
 309                 strbuf_addstr(&sb, i->string);
 310                 strbuf_trim(&sb);
 311
 312                 if (!strcmp(sb.buf, "no"))
 313                         ret = 0;
 314                 else if (!strcmp(sb.buf, "ignore-space-change"))
 315                         ret |= XDF_IGNORE_WHITESPACE_CHANGE;
 316                 else if (!strcmp(sb.buf, "ignore-space-at-eol"))
 317                         ret |= XDF_IGNORE_WHITESPACE_AT_EOL;
 318                 else if (!strcmp(sb.buf, "ignore-all-space"))
 319                         ret |= XDF_IGNORE_WHITESPACE;
 320                 else if (!strcmp(sb.buf, "allow-indentation-change"))
 321                         ret |= COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE;
 322                 else {
 323                         ret |= COLOR_MOVED_WS_ERROR;
 324                         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);
 325                 }
 326
 327                 strbuf_release(&sb);
 328         }
 329
 330         if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
 331             (ret & XDF_WHITESPACE_FLAGS)) {
 332                 error(_("color-moved-ws: allow-indentation-change cannot be combined with other whitespace modes"));
 333                 ret |= COLOR_MOVED_WS_ERROR;
 334         }
 335
 336         string_list_clear(&l, 0);
 337
 338         return ret;
 339 }
 340
 341 int git_diff_ui_config(const char *var, const char *value, void *cb)
 342 {
 343         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 344                 diff_use_color_default = git_config_colorbool(var, value);
 345                 return 0;
 346         }
 347         if (!strcmp(var, "diff.colormoved")) {
 348                 int cm = parse_color_moved(value);
 349                 if (cm < 0)
 350                         return -1;
 351                 diff_color_moved_default = cm;
 352                 return 0;
 353         }
 354         if (!strcmp(var, "diff.colormovedws")) {
 355                 unsigned cm = parse_color_moved_ws(value);
 356                 if (cm & COLOR_MOVED_WS_ERROR)
 357                         return -1;
 358                 diff_color_moved_ws_default = cm;
 359                 return 0;
 360         }
 361         if (!strcmp(var, "diff.context")) {
 362                 diff_context_default = git_config_int(var, value);
 363                 if (diff_context_default < 0)
 364                         return -1;
 365                 return 0;
 366         }
 367         if (!strcmp(var, "diff.interhunkcontext")) {
 368                 diff_interhunk_context_default = git_config_int(var, value);
 369                 if (diff_interhunk_context_default < 0)
 370                         return -1;
 371                 return 0;
 372         }
 373         if (!strcmp(var, "diff.renames")) {
 374                 diff_detect_rename_default = git_config_rename(var, value);
 375                 return 0;
 376         }
 377         if (!strcmp(var, "diff.autorefreshindex")) {
 378                 diff_auto_refresh_index = git_config_bool(var, value);
 379                 return 0;
 380         }
 381         if (!strcmp(var, "diff.mnemonicprefix")) {
 382                 diff_mnemonic_prefix = git_config_bool(var, value);
 383                 return 0;
 384         }
 385         if (!strcmp(var, "diff.noprefix")) {
 386                 diff_no_prefix = git_config_bool(var, value);
 387                 return 0;
 388         }
 389         if (!strcmp(var, "diff.statgraphwidth")) {
 390                 diff_stat_graph_width = git_config_int(var, value);
 391                 return 0;
 392         }
 393         if (!strcmp(var, "diff.external"))
 394                 return git_config_string(&external_diff_cmd_cfg, var, value);
 395         if (!strcmp(var, "diff.wordregex"))
 396                 return git_config_string(&diff_word_regex_cfg, var, value);
 397         if (!strcmp(var, "diff.orderfile"))
 398                 return git_config_pathname(&diff_order_file_cfg, var, value);
 399
 400         if (!strcmp(var, "diff.ignoresubmodules"))
 401                 handle_ignore_submodules_arg(&default_diff_options, value);
 402
 403         if (!strcmp(var, "diff.submodule")) {
 404                 if (parse_submodule_params(&default_diff_options, value))
 405                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 406                                 value);
 407                 return 0;
 408         }
 409
 410         if (!strcmp(var, "diff.algorithm")) {
 411                 diff_algorithm = parse_algorithm_value(value);
 412                 if (diff_algorithm < 0)
 413                         return -1;
 414                 return 0;
 415         }
 416
 417         if (!strcmp(var, "diff.wserrorhighlight")) {
 418                 int val = parse_ws_error_highlight(value);
 419                 if (val < 0)
 420                         return -1;
 421                 ws_error_highlight_default = val;
 422                 return 0;
 423         }
 424
 425         if (git_color_config(var, value, cb) < 0)
 426                 return -1;
 427
 428         return git_diff_basic_config(var, value, cb);
 429 }
 430
 431 int git_diff_basic_config(const char *var, const char *value, void *cb)
 432 {
 433         const char *name;
 434
 435         if (!strcmp(var, "diff.renamelimit")) {
 436                 diff_rename_limit_default = git_config_int(var, value);
 437                 return 0;
 438         }
 439
 440         if (userdiff_config(var, value) < 0)
 441                 return -1;
 442
 443         if (skip_prefix(var, "diff.color.", &name) ||
 444             skip_prefix(var, "color.diff.", &name)) {
 445                 int slot = parse_diff_color_slot(name);
 446                 if (slot < 0)
 447                         return 0;
 448                 if (!value)
 449                         return config_error_nonbool(var);
 450                 return color_parse(value, diff_colors[slot]);
 451         }
 452
 453         /* like GNU diff's --suppress-blank-empty option  */
 454         if (!strcmp(var, "diff.suppressblankempty") ||
 455                         /* for backwards compatibility */
 456                         !strcmp(var, "diff.suppress-blank-empty")) {
 457                 diff_suppress_blank_empty = git_config_bool(var, value);
 458                 return 0;
 459         }
 460
 461         if (!strcmp(var, "diff.dirstat")) {
 462                 struct strbuf errmsg = STRBUF_INIT;
 463                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 464                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 465                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 466                                 errmsg.buf);
 467                 strbuf_release(&errmsg);
 468                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 469                 return 0;
 470         }
 471
 472         if (git_diff_heuristic_config(var, value, cb) < 0)
 473                 return -1;
 474
 475         return git_default_config(var, value, cb);
 476 }
 477
 478 static char *quote_two(const char *one, const char *two)
 479 {
 480         int need_one = quote_c_style(one, NULL, NULL, 1);
 481         int need_two = quote_c_style(two, NULL, NULL, 1);
 482         struct strbuf res = STRBUF_INIT;
 483
 484         if (need_one + need_two) {
 485                 strbuf_addch(&res, '"');
 486                 quote_c_style(one, &res, NULL, 1);
 487                 quote_c_style(two, &res, NULL, 1);
 488                 strbuf_addch(&res, '"');
 489         } else {
 490                 strbuf_addstr(&res, one);
 491                 strbuf_addstr(&res, two);
 492         }
 493         return strbuf_detach(&res, NULL);
 494 }
 495
 496 static const char *external_diff(void)
 497 {
 498         static const char *external_diff_cmd = NULL;
 499         static int done_preparing = 0;
 500
 501         if (done_preparing)
 502                 return external_diff_cmd;
 503         external_diff_cmd = xstrdup_or_null(getenv("GIT_EXTERNAL_DIFF"));
 504         if (!external_diff_cmd)
 505                 external_diff_cmd = external_diff_cmd_cfg;
 506         done_preparing = 1;
 507         return external_diff_cmd;
 508 }
 509
 510 /*
 511  * Keep track of files used for diffing. Sometimes such an entry
 512  * refers to a temporary file, sometimes to an existing file, and
 513  * sometimes to "/dev/null".
 514  */
 515 static struct diff_tempfile {
 516         /*
 517          * filename external diff should read from, or NULL if this
 518          * entry is currently not in use:
 519          */
 520         const char *name;
 521
 522         char hex[GIT_MAX_HEXSZ + 1];
 523         char mode[10];
 524
 525         /*
 526          * If this diff_tempfile instance refers to a temporary file,
 527          * this tempfile object is used to manage its lifetime.
 528          */
 529         struct tempfile *tempfile;
 530 } diff_temp[2];
 531
 532 struct emit_callback {
 533         int color_diff;
 534         unsigned ws_rule;
 535         int blank_at_eof_in_preimage;
 536         int blank_at_eof_in_postimage;
 537         int lno_in_preimage;
 538         int lno_in_postimage;
 539         const char **label_path;
 540         struct diff_words_data *diff_words;
 541         struct diff_options *opt;
 542         struct strbuf *header;
 543 };
 544
 545 static int count_lines(const char *data, int size)
 546 {
 547         int count, ch, completely_empty = 1, nl_just_seen = 0;
 548         count = 0;
 549         while (0 < size--) {
 550                 ch = *data++;
 551                 if (ch == '\n') {
 552                         count++;
 553                         nl_just_seen = 1;
 554                         completely_empty = 0;
 555                 }
 556                 else {
 557                         nl_just_seen = 0;
 558                         completely_empty = 0;
 559                 }
 560         }
 561         if (completely_empty)
 562                 return 0;
 563         if (!nl_just_seen)
 564                 count++; /* no trailing newline */
 565         return count;
 566 }
 567
 568 static int fill_mmfile(struct repository *r, mmfile_t *mf,
 569                        struct diff_filespec *one)
 570 {
 571         if (!DIFF_FILE_VALID(one)) {
 572                 mf->ptr = (char *)""; /* does not matter */
 573                 mf->size = 0;
 574                 return 0;
 575         }
 576         else if (diff_populate_filespec(r, one, 0))
 577                 return -1;
 578
 579         mf->ptr = one->data;
 580         mf->size = one->size;
 581         return 0;
 582 }
 583
 584 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 585 static unsigned long diff_filespec_size(struct repository *r,
 586                                         struct diff_filespec *one)
 587 {
 588         if (!DIFF_FILE_VALID(one))
 589                 return 0;
 590         diff_populate_filespec(r, one, CHECK_SIZE_ONLY);
 591         return one->size;
 592 }
 593
 594 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 595 {
 596         char *ptr = mf->ptr;
 597         long size = mf->size;
 598         int cnt = 0;
 599
 600         if (!size)
 601                 return cnt;
 602         ptr += size - 1; /* pointing at the very end */
 603         if (*ptr != '\n')
 604                 ; /* incomplete line */
 605         else
 606                 ptr--; /* skip the last LF */
 607         while (mf->ptr < ptr) {
 608                 char *prev_eol;
 609                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 610                         if (*prev_eol == '\n')
 611                                 break;
 612                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 613                         break;
 614                 cnt++;
 615                 ptr = prev_eol - 1;
 616         }
 617         return cnt;
 618 }
 619
 620 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 621                                struct emit_callback *ecbdata)
 622 {
 623         int l1, l2, at;
 624         unsigned ws_rule = ecbdata->ws_rule;
 625         l1 = count_trailing_blank(mf1, ws_rule);
 626         l2 = count_trailing_blank(mf2, ws_rule);
 627         if (l2 <= l1) {
 628                 ecbdata->blank_at_eof_in_preimage = 0;
 629                 ecbdata->blank_at_eof_in_postimage = 0;
 630                 return;
 631         }
 632         at = count_lines(mf1->ptr, mf1->size);
 633         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 634
 635         at = count_lines(mf2->ptr, mf2->size);
 636         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 637 }
 638
 639 static void emit_line_0(struct diff_options *o,
 640                         const char *set_sign, const char *set, unsigned reverse, const char *reset,
 641                         int first, const char *line, int len)
 642 {
 643         int has_trailing_newline, has_trailing_carriage_return;
 644         int needs_reset = 0; /* at the end of the line */
 645         FILE *file = o->file;
 646
 647         fputs(diff_line_prefix(o), file);
 648
 649         has_trailing_newline = (len > 0 && line[len-1] == '\n');
 650         if (has_trailing_newline)
 651                 len--;
 652
 653         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 654         if (has_trailing_carriage_return)
 655                 len--;
 656
 657         if (!len && !first)
 658                 goto end_of_line;
 659
 660         if (reverse && want_color(o->use_color)) {
 661                 fputs(GIT_COLOR_REVERSE, file);
 662                 needs_reset = 1;
 663         }
 664
 665         if (set_sign) {
 666                 fputs(set_sign, file);
 667                 needs_reset = 1;
 668         }
 669
 670         if (first)
 671                 fputc(first, file);
 672
 673         if (!len)
 674                 goto end_of_line;
 675
 676         if (set) {
 677                 if (set_sign && set != set_sign)
 678                         fputs(reset, file);
 679                 fputs(set, file);
 680                 needs_reset = 1;
 681         }
 682         fwrite(line, len, 1, file);
 683         needs_reset = 1; /* 'line' may contain color codes. */
 684
 685 end_of_line:
 686         if (needs_reset)
 687                 fputs(reset, file);
 688         if (has_trailing_carriage_return)
 689                 fputc('\r', file);
 690         if (has_trailing_newline)
 691                 fputc('\n', file);
 692 }
 693
 694 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 695                       const char *line, int len)
 696 {
 697         emit_line_0(o, set, NULL, 0, reset, 0, line, len);
 698 }
 699
 700 enum diff_symbol {
 701         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 702         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 703         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 704         DIFF_SYMBOL_BINARY_DIFF_BODY,
 705         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 706         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 707         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 708         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 709         DIFF_SYMBOL_STATS_LINE,
 710         DIFF_SYMBOL_WORD_DIFF,
 711         DIFF_SYMBOL_STAT_SEP,
 712         DIFF_SYMBOL_SUMMARY,
 713         DIFF_SYMBOL_SUBMODULE_ADD,
 714         DIFF_SYMBOL_SUBMODULE_DEL,
 715         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 716         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 717         DIFF_SYMBOL_SUBMODULE_HEADER,
 718         DIFF_SYMBOL_SUBMODULE_ERROR,
 719         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 720         DIFF_SYMBOL_REWRITE_DIFF,
 721         DIFF_SYMBOL_BINARY_FILES,
 722         DIFF_SYMBOL_HEADER,
 723         DIFF_SYMBOL_FILEPAIR_PLUS,
 724         DIFF_SYMBOL_FILEPAIR_MINUS,
 725         DIFF_SYMBOL_WORDS_PORCELAIN,
 726         DIFF_SYMBOL_WORDS,
 727         DIFF_SYMBOL_CONTEXT,
 728         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 729         DIFF_SYMBOL_PLUS,
 730         DIFF_SYMBOL_MINUS,
 731         DIFF_SYMBOL_NO_LF_EOF,
 732         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 733         DIFF_SYMBOL_CONTEXT_MARKER,
 734         DIFF_SYMBOL_SEPARATOR
 735 };
 736 /*
 737  * Flags for content lines:
 738  * 0..12 are whitespace rules
 739  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 740  * 16 is marking if the line is blank at EOF
 741  */
 742 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 743 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 744 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 745 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 746 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 747
 748 /*
 749  * This struct is used when we need to buffer the output of the diff output.
 750  *
 751  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 752  * into the pre/post image file. This pointer could be a union with the
 753  * line pointer. By storing an offset into the file instead of the literal line,
 754  * we can decrease the memory footprint for the buffered output. At first we
 755  * may want to only have indirection for the content lines, but we could also
 756  * enhance the state for emitting prefabricated lines, e.g. the similarity
 757  * score line or hunk/file headers would only need to store a number or path
 758  * and then the output can be constructed later on depending on state.
 759  */
 760 struct emitted_diff_symbol {
 761         const char *line;
 762         int len;
 763         int flags;
 764         int indent_off;   /* Offset to first non-whitespace character */
 765         int indent_width; /* The visual width of the indentation */
 766         enum diff_symbol s;
 767 };
 768 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 769
 770 struct emitted_diff_symbols {
 771         struct emitted_diff_symbol *buf;
 772         int nr, alloc;
 773 };
 774 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 775
 776 static void append_emitted_diff_symbol(struct diff_options *o,
 777                                        struct emitted_diff_symbol *e)
 778 {
 779         struct emitted_diff_symbol *f;
 780
 781         ALLOC_GROW(o->emitted_symbols->buf,
 782                    o->emitted_symbols->nr + 1,
 783                    o->emitted_symbols->alloc);
 784         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 785
 786         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 787         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 788 }
 789
 790 struct moved_entry {
 791         struct hashmap_entry ent;
 792         const struct emitted_diff_symbol *es;
 793         struct moved_entry *next_line;
 794 };
 795
 796 struct moved_block {
 797         struct moved_entry *match;
 798         int wsd; /* The whitespace delta of this block */
 799 };
 800
 801 static void moved_block_clear(struct moved_block *b)
 802 {
 803         memset(b, 0, sizeof(*b));
 804 }
 805
 806 #define INDENT_BLANKLINE INT_MIN
 807
 808 static void fill_es_indent_data(struct emitted_diff_symbol *es)
 809 {
 810         unsigned int off = 0, i;
 811         int width = 0, tab_width = es->flags & WS_TAB_WIDTH_MASK;
 812         const char *s = es->line;
 813         const int len = es->len;
 814
 815         /* skip any \v \f \r at start of indentation */
 816         while (s[off] == '\f' || s[off] == '\v' ||
 817                (s[off] == '\r' && off < len - 1))
 818                 off++;
 819
 820         /* calculate the visual width of indentation */
 821         while(1) {
 822                 if (s[off] == ' ') {
 823                         width++;
 824                         off++;
 825                 } else if (s[off] == '\t') {
 826                         width += tab_width - (width % tab_width);
 827                         while (s[++off] == '\t')
 828                                 width += tab_width;
 829                 } else {
 830                         break;
 831                 }
 832         }
 833
 834         /* check if this line is blank */
 835         for (i = off; i < len; i++)
 836                 if (!isspace(s[i]))
 837                     break;
 838
 839         if (i == len) {
 840                 es->indent_width = INDENT_BLANKLINE;
 841                 es->indent_off = len;
 842         } else {
 843                 es->indent_off = off;
 844                 es->indent_width = width;
 845         }
 846 }
 847
 848 static int compute_ws_delta(const struct emitted_diff_symbol *a,
 849                             const struct emitted_diff_symbol *b,
 850                             int *out)
 851 {
 852         int a_len = a->len,
 853             b_len = b->len,
 854             a_off = a->indent_off,
 855             a_width = a->indent_width,
 856             b_off = b->indent_off,
 857             b_width = b->indent_width;
 858         int delta;
 859
 860         if (a_width == INDENT_BLANKLINE && b_width == INDENT_BLANKLINE) {
 861                 *out = INDENT_BLANKLINE;
 862                 return 1;
 863         }
 864
 865         if (a->s == DIFF_SYMBOL_PLUS)
 866                 delta = a_width - b_width;
 867         else
 868                 delta = b_width - a_width;
 869
 870         if (a_len - a_off != b_len - b_off ||
 871             memcmp(a->line + a_off, b->line + b_off, a_len - a_off))
 872                 return 0;
 873
 874         *out = delta;
 875
 876         return 1;
 877 }
 878
 879 static int cmp_in_block_with_wsd(const struct diff_options *o,
 880                                  const struct moved_entry *cur,
 881                                  const struct moved_entry *match,
 882                                  struct moved_block *pmb,
 883                                  int n)
 884 {
 885         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 886         int al = cur->es->len, bl = match->es->len, cl = l->len;
 887         const char *a = cur->es->line,
 888                    *b = match->es->line,
 889                    *c = l->line;
 890         int a_off = cur->es->indent_off,
 891             a_width = cur->es->indent_width,
 892             c_off = l->indent_off,
 893             c_width = l->indent_width;
 894         int delta;
 895
 896         /*
 897          * We need to check if 'cur' is equal to 'match'.  As those
 898          * are from the same (+/-) side, we do not need to adjust for
 899          * indent changes. However these were found using fuzzy
 900          * matching so we do have to check if they are equal. Here we
 901          * just check the lengths. We delay calling memcmp() to check
 902          * the contents until later as if the length comparison for a
 903          * and c fails we can avoid the call all together.
 904          */
 905         if (al != bl)
 906                 return 1;
 907
 908         /* If 'l' and 'cur' are both blank then they match. */
 909         if (a_width == INDENT_BLANKLINE && c_width == INDENT_BLANKLINE)
 910                 return 0;
 911
 912         /*
 913          * The indent changes of the block are known and stored in pmb->wsd;
 914          * however we need to check if the indent changes of the current line
 915          * match those of the current block and that the text of 'l' and 'cur'
 916          * after the indentation match.
 917          */
 918         if (cur->es->s == DIFF_SYMBOL_PLUS)
 919                 delta = a_width - c_width;
 920         else
 921                 delta = c_width - a_width;
 922
 923         /*
 924          * If the previous lines of this block were all blank then set its
 925          * whitespace delta.
 926          */
 927         if (pmb->wsd == INDENT_BLANKLINE)
 928                 pmb->wsd = delta;
 929
 930         return !(delta == pmb->wsd && al - a_off == cl - c_off &&
 931                  !memcmp(a, b, al) && !
 932                  memcmp(a + a_off, c + c_off, al - a_off));
 933 }
 934
 935 static int moved_entry_cmp(const void *hashmap_cmp_fn_data,
 936                            const void *entry,
 937                            const void *entry_or_key,
 938                            const void *keydata)
 939 {
 940         const struct diff_options *diffopt = hashmap_cmp_fn_data;
 941         const struct moved_entry *a = entry;
 942         const struct moved_entry *b = entry_or_key;
 943         unsigned flags = diffopt->color_moved_ws_handling
 944                          & XDF_WHITESPACE_FLAGS;
 945
 946         if (diffopt->color_moved_ws_handling &
 947             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
 948                 /*
 949                  * As there is not specific white space config given,
 950                  * we'd need to check for a new block, so ignore all
 951                  * white space. The setup of the white space
 952                  * configuration for the next block is done else where
 953                  */
 954                 flags |= XDF_IGNORE_WHITESPACE;
 955
 956         return !xdiff_compare_lines(a->es->line, a->es->len,
 957                                     b->es->line, b->es->len,
 958                                     flags);
 959 }
 960
 961 static struct moved_entry *prepare_entry(struct diff_options *o,
 962                                          int line_no)
 963 {
 964         struct moved_entry *ret = xmalloc(sizeof(*ret));
 965         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 966         unsigned flags = o->color_moved_ws_handling & XDF_WHITESPACE_FLAGS;
 967
 968         ret->ent.hash = xdiff_hash_string(l->line, l->len, flags);
 969         ret->es = l;
 970         ret->next_line = NULL;
 971
 972         return ret;
 973 }
 974
 975 static void add_lines_to_move_detection(struct diff_options *o,
 976                                         struct hashmap *add_lines,
 977                                         struct hashmap *del_lines)
 978 {
 979         struct moved_entry *prev_line = NULL;
 980
 981         int n;
 982         for (n = 0; n < o->emitted_symbols->nr; n++) {
 983                 struct hashmap *hm;
 984                 struct moved_entry *key;
 985
 986                 switch (o->emitted_symbols->buf[n].s) {
 987                 case DIFF_SYMBOL_PLUS:
 988                         hm = add_lines;
 989                         break;
 990                 case DIFF_SYMBOL_MINUS:
 991                         hm = del_lines;
 992                         break;
 993                 default:
 994                         prev_line = NULL;
 995                         continue;
 996                 }
 997
 998                 if (o->color_moved_ws_handling &
 999                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
1000                         fill_es_indent_data(&o->emitted_symbols->buf[n]);
1001                 key = prepare_entry(o, n);
1002                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
1003                         prev_line->next_line = key;
1004
1005                 hashmap_add(hm, key);
1006                 prev_line = key;
1007         }
1008 }
1009
1010 static void pmb_advance_or_null(struct diff_options *o,
1011                                 struct moved_entry *match,
1012                                 struct hashmap *hm,
1013                                 struct moved_block *pmb,
1014                                 int pmb_nr)
1015 {
1016         int i;
1017         for (i = 0; i < pmb_nr; i++) {
1018                 struct moved_entry *prev = pmb[i].match;
1019                 struct moved_entry *cur = (prev && prev->next_line) ?
1020                                 prev->next_line : NULL;
1021                 if (cur && !hm->cmpfn(o, cur, match, NULL)) {
1022                         pmb[i].match = cur;
1023                 } else {
1024                         pmb[i].match = NULL;
1025                 }
1026         }
1027 }
1028
1029 static void pmb_advance_or_null_multi_match(struct diff_options *o,
1030                                             struct moved_entry *match,
1031                                             struct hashmap *hm,
1032                                             struct moved_block *pmb,
1033                                             int pmb_nr, int n)
1034 {
1035         int i;
1036         char *got_match = xcalloc(1, pmb_nr);
1037
1038         for (; match; match = hashmap_get_next(hm, match)) {
1039                 for (i = 0; i < pmb_nr; i++) {
1040                         struct moved_entry *prev = pmb[i].match;
1041                         struct moved_entry *cur = (prev && prev->next_line) ?
1042                                         prev->next_line : NULL;
1043                         if (!cur)
1044                                 continue;
1045                         if (!cmp_in_block_with_wsd(o, cur, match, &pmb[i], n))
1046                                 got_match[i] |= 1;
1047                 }
1048         }
1049
1050         for (i = 0; i < pmb_nr; i++) {
1051                 if (got_match[i]) {
1052                         /* Advance to the next line */
1053                         pmb[i].match = pmb[i].match->next_line;
1054                 } else {
1055                         moved_block_clear(&pmb[i]);
1056                 }
1057         }
1058
1059         free(got_match);
1060 }
1061
1062 static int shrink_potential_moved_blocks(struct moved_block *pmb,
1063                                          int pmb_nr)
1064 {
1065         int lp, rp;
1066
1067         /* Shrink the set of potential block to the remaining running */
1068         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
1069                 while (lp < pmb_nr && pmb[lp].match)
1070                         lp++;
1071                 /* lp points at the first NULL now */
1072
1073                 while (rp > -1 && !pmb[rp].match)
1074                         rp--;
1075                 /* rp points at the last non-NULL */
1076
1077                 if (lp < pmb_nr && rp > -1 && lp < rp) {
1078                         pmb[lp] = pmb[rp];
1079                         memset(&pmb[rp], 0, sizeof(pmb[rp]));
1080                         rp--;
1081                         lp++;
1082                 }
1083         }
1084
1085         /* Remember the number of running sets */
1086         return rp + 1;
1087 }
1088
1089 /*
1090  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
1091  *
1092  * Otherwise, if the last block has fewer alphanumeric characters than
1093  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
1094  * that block.
1095  *
1096  * The last block consists of the (n - block_length)'th line up to but not
1097  * including the nth line.
1098  *
1099  * Returns 0 if the last block is empty or is unset by this function, non zero
1100  * otherwise.
1101  *
1102  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
1103  * Think of a way to unify them.
1104  */
1105 static int adjust_last_block(struct diff_options *o, int n, int block_length)
1106 {
1107         int i, alnum_count = 0;
1108         if (o->color_moved == COLOR_MOVED_PLAIN)
1109                 return block_length;
1110         for (i = 1; i < block_length + 1; i++) {
1111                 const char *c = o->emitted_symbols->buf[n - i].line;
1112                 for (; *c; c++) {
1113                         if (!isalnum(*c))
1114                                 continue;
1115                         alnum_count++;
1116                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
1117                                 return 1;
1118                 }
1119         }
1120         for (i = 1; i < block_length + 1; i++)
1121                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
1122         return 0;
1123 }
1124
1125 /* Find blocks of moved code, delegate actual coloring decision to helper */
1126 static void mark_color_as_moved(struct diff_options *o,
1127                                 struct hashmap *add_lines,
1128                                 struct hashmap *del_lines)
1129 {
1130         struct moved_block *pmb = NULL; /* potentially moved blocks */
1131         int pmb_nr = 0, pmb_alloc = 0;
1132         int n, flipped_block = 0, block_length = 0;
1133
1134
1135         for (n = 0; n < o->emitted_symbols->nr; n++) {
1136                 struct hashmap *hm = NULL;
1137                 struct moved_entry *key;
1138                 struct moved_entry *match = NULL;
1139                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1140                 enum diff_symbol last_symbol = 0;
1141
1142                 switch (l->s) {
1143                 case DIFF_SYMBOL_PLUS:
1144                         hm = del_lines;
1145                         key = prepare_entry(o, n);
1146                         match = hashmap_get(hm, key, NULL);
1147                         free(key);
1148                         break;
1149                 case DIFF_SYMBOL_MINUS:
1150                         hm = add_lines;
1151                         key = prepare_entry(o, n);
1152                         match = hashmap_get(hm, key, NULL);
1153                         free(key);
1154                         break;
1155                 default:
1156                         flipped_block = 0;
1157                 }
1158
1159                 if (!match) {
1160                         int i;
1161
1162                         adjust_last_block(o, n, block_length);
1163                         for(i = 0; i < pmb_nr; i++)
1164                                 moved_block_clear(&pmb[i]);
1165                         pmb_nr = 0;
1166                         block_length = 0;
1167                         flipped_block = 0;
1168                         last_symbol = l->s;
1169                         continue;
1170                 }
1171
1172                 if (o->color_moved == COLOR_MOVED_PLAIN) {
1173                         last_symbol = l->s;
1174                         l->flags |= DIFF_SYMBOL_MOVED_LINE;
1175                         continue;
1176                 }
1177
1178                 if (o->color_moved_ws_handling &
1179                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
1180                         pmb_advance_or_null_multi_match(o, match, hm, pmb, pmb_nr, n);
1181                 else
1182                         pmb_advance_or_null(o, match, hm, pmb, pmb_nr);
1183
1184                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
1185
1186                 if (pmb_nr == 0) {
1187                         /*
1188                          * The current line is the start of a new block.
1189                          * Setup the set of potential blocks.
1190                          */
1191                         for (; match; match = hashmap_get_next(hm, match)) {
1192                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
1193                                 if (o->color_moved_ws_handling &
1194                                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) {
1195                                         if (compute_ws_delta(l, match->es,
1196                                                              &pmb[pmb_nr].wsd))
1197                                                 pmb[pmb_nr++].match = match;
1198                                 } else {
1199                                         pmb[pmb_nr].wsd = 0;
1200                                         pmb[pmb_nr++].match = match;
1201                                 }
1202                         }
1203
1204                         if (adjust_last_block(o, n, block_length) &&
1205                             pmb_nr && last_symbol != l->s)
1206                                 flipped_block = (flipped_block + 1) % 2;
1207                         else
1208                                 flipped_block = 0;
1209
1210                         block_length = 0;
1211                 }
1212
1213                 if (pmb_nr) {
1214                         block_length++;
1215                         l->flags |= DIFF_SYMBOL_MOVED_LINE;
1216                         if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
1217                                 l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
1218                 }
1219                 last_symbol = l->s;
1220         }
1221         adjust_last_block(o, n, block_length);
1222
1223         for(n = 0; n < pmb_nr; n++)
1224                 moved_block_clear(&pmb[n]);
1225         free(pmb);
1226 }
1227
1228 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
1229   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
1230 static void dim_moved_lines(struct diff_options *o)
1231 {
1232         int n;
1233         for (n = 0; n < o->emitted_symbols->nr; n++) {
1234                 struct emitted_diff_symbol *prev = (n != 0) ?
1235                                 &o->emitted_symbols->buf[n - 1] : NULL;
1236                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1237                 struct emitted_diff_symbol *next =
1238                                 (n < o->emitted_symbols->nr - 1) ?
1239                                 &o->emitted_symbols->buf[n + 1] : NULL;
1240
1241                 /* Not a plus or minus line? */
1242                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
1243                         continue;
1244
1245                 /* Not a moved line? */
1246                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
1247                         continue;
1248
1249                 /*
1250                  * If prev or next are not a plus or minus line,
1251                  * pretend they don't exist
1252                  */
1253                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
1254                             prev->s != DIFF_SYMBOL_MINUS)
1255                         prev = NULL;
1256                 if (next && next->s != DIFF_SYMBOL_PLUS &&
1257                             next->s != DIFF_SYMBOL_MINUS)
1258                         next = NULL;
1259
1260                 /* Inside a block? */
1261                 if ((prev &&
1262                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1263                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
1264                     (next &&
1265                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1266                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
1267                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1268                         continue;
1269                 }
1270
1271                 /* Check if we are at an interesting bound: */
1272                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
1273                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1274                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1275                         continue;
1276                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
1277                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1278                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1279                         continue;
1280
1281                 /*
1282                  * The boundary to prev and next are not interesting,
1283                  * so this line is not interesting as a whole
1284                  */
1285                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1286         }
1287 }
1288
1289 static void emit_line_ws_markup(struct diff_options *o,
1290                                 const char *set_sign, const char *set,
1291                                 const char *reset,
1292                                 int sign_index, const char *line, int len,
1293                                 unsigned ws_rule, int blank_at_eof)
1294 {
1295         const char *ws = NULL;
1296         int sign = o->output_indicators[sign_index];
1297
1298         if (o->ws_error_highlight & ws_rule) {
1299                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
1300                 if (!*ws)
1301                         ws = NULL;
1302         }
1303
1304         if (!ws && !set_sign)
1305                 emit_line_0(o, set, NULL, 0, reset, sign, line, len);
1306         else if (!ws) {
1307                 emit_line_0(o, set_sign, set, !!set_sign, reset, sign, line, len);
1308         } else if (blank_at_eof)
1309                 /* Blank line at EOF - paint '+' as well */
1310                 emit_line_0(o, ws, NULL, 0, reset, sign, line, len);
1311         else {
1312                 /* Emit just the prefix, then the rest. */
1313                 emit_line_0(o, set_sign ? set_sign : set, NULL, !!set_sign, reset,
1314                             sign, "", 0);
1315                 ws_check_emit(line, len, ws_rule,
1316                               o->file, set, reset, ws);
1317         }
1318 }
1319
1320 static void emit_diff_symbol_from_struct(struct diff_options *o,
1321                                          struct emitted_diff_symbol *eds)
1322 {
1323         static const char *nneof = " No newline at end of file\n";
1324         const char *context, *reset, *set, *set_sign, *meta, *fraginfo;
1325         struct strbuf sb = STRBUF_INIT;
1326
1327         enum diff_symbol s = eds->s;
1328         const char *line = eds->line;
1329         int len = eds->len;
1330         unsigned flags = eds->flags;
1331
1332         switch (s) {
1333         case DIFF_SYMBOL_NO_LF_EOF:
1334                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1335                 reset = diff_get_color_opt(o, DIFF_RESET);
1336                 putc('\n', o->file);
1337                 emit_line_0(o, context, NULL, 0, reset, '\\',
1338                             nneof, strlen(nneof));
1339                 break;
1340         case DIFF_SYMBOL_SUBMODULE_HEADER:
1341         case DIFF_SYMBOL_SUBMODULE_ERROR:
1342         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1343         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1344         case DIFF_SYMBOL_SUMMARY:
1345         case DIFF_SYMBOL_STATS_LINE:
1346         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1347         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1348                 emit_line(o, "", "", line, len);
1349                 break;
1350         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1351         case DIFF_SYMBOL_CONTEXT_MARKER:
1352                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1353                 reset = diff_get_color_opt(o, DIFF_RESET);
1354                 emit_line(o, context, reset, line, len);
1355                 break;
1356         case DIFF_SYMBOL_SEPARATOR:
1357                 fprintf(o->file, "%s%c",
1358                         diff_line_prefix(o),
1359                         o->line_termination);
1360                 break;
1361         case DIFF_SYMBOL_CONTEXT:
1362                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1363                 reset = diff_get_color_opt(o, DIFF_RESET);
1364                 set_sign = NULL;
1365                 if (o->flags.dual_color_diffed_diffs) {
1366                         char c = !len ? 0 : line[0];
1367
1368                         if (c == '+')
1369                                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1370                         else if (c == '@')
1371                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1372                         else if (c == '-')
1373                                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1374                 }
1375                 emit_line_ws_markup(o, set_sign, set, reset,
1376                                     OUTPUT_INDICATOR_CONTEXT, line, len,
1377                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1378                 break;
1379         case DIFF_SYMBOL_PLUS:
1380                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1381                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1382                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1383                 case DIFF_SYMBOL_MOVED_LINE |
1384                      DIFF_SYMBOL_MOVED_LINE_ALT |
1385                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1386                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1387                         break;
1388                 case DIFF_SYMBOL_MOVED_LINE |
1389                      DIFF_SYMBOL_MOVED_LINE_ALT:
1390                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1391                         break;
1392                 case DIFF_SYMBOL_MOVED_LINE |
1393                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1394                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1395                         break;
1396                 case DIFF_SYMBOL_MOVED_LINE:
1397                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1398                         break;
1399                 default:
1400                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1401                 }
1402                 reset = diff_get_color_opt(o, DIFF_RESET);
1403                 if (!o->flags.dual_color_diffed_diffs)
1404                         set_sign = NULL;
1405                 else {
1406                         char c = !len ? 0 : line[0];
1407
1408                         set_sign = set;
1409                         if (c == '-')
1410                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_BOLD);
1411                         else if (c == '@')
1412                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1413                         else if (c == '+')
1414                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_BOLD);
1415                         else
1416                                 set = diff_get_color_opt(o, DIFF_CONTEXT_BOLD);
1417                         flags &= ~DIFF_SYMBOL_CONTENT_WS_MASK;
1418                 }
1419                 emit_line_ws_markup(o, set_sign, set, reset,
1420                                     OUTPUT_INDICATOR_NEW, line, len,
1421                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1422                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1423                 break;
1424         case DIFF_SYMBOL_MINUS:
1425                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1426                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1427                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1428                 case DIFF_SYMBOL_MOVED_LINE |
1429                      DIFF_SYMBOL_MOVED_LINE_ALT |
1430                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1431                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1432                         break;
1433                 case DIFF_SYMBOL_MOVED_LINE |
1434                      DIFF_SYMBOL_MOVED_LINE_ALT:
1435                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1436                         break;
1437                 case DIFF_SYMBOL_MOVED_LINE |
1438                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1439                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1440                         break;
1441                 case DIFF_SYMBOL_MOVED_LINE:
1442                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1443                         break;
1444                 default:
1445                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1446                 }
1447                 reset = diff_get_color_opt(o, DIFF_RESET);
1448                 if (!o->flags.dual_color_diffed_diffs)
1449                         set_sign = NULL;
1450                 else {
1451                         char c = !len ? 0 : line[0];
1452
1453                         set_sign = set;
1454                         if (c == '+')
1455                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_DIM);
1456                         else if (c == '@')
1457                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1458                         else if (c == '-')
1459                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_DIM);
1460                         else
1461                                 set = diff_get_color_opt(o, DIFF_CONTEXT_DIM);
1462                 }
1463                 emit_line_ws_markup(o, set_sign, set, reset,
1464                                     OUTPUT_INDICATOR_OLD, line, len,
1465                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1466                 break;
1467         case DIFF_SYMBOL_WORDS_PORCELAIN:
1468                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1469                 reset = diff_get_color_opt(o, DIFF_RESET);
1470                 emit_line(o, context, reset, line, len);
1471                 fputs("~\n", o->file);
1472                 break;
1473         case DIFF_SYMBOL_WORDS:
1474                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1475                 reset = diff_get_color_opt(o, DIFF_RESET);
1476                 /*
1477                  * Skip the prefix character, if any.  With
1478                  * diff_suppress_blank_empty, there may be
1479                  * none.
1480                  */
1481                 if (line[0] != '\n') {
1482                         line++;
1483                         len--;
1484                 }
1485                 emit_line(o, context, reset, line, len);
1486                 break;
1487         case DIFF_SYMBOL_FILEPAIR_PLUS:
1488                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1489                 reset = diff_get_color_opt(o, DIFF_RESET);
1490                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1491                         line, reset,
1492                         strchr(line, ' ') ? "\t" : "");
1493                 break;
1494         case DIFF_SYMBOL_FILEPAIR_MINUS:
1495                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1496                 reset = diff_get_color_opt(o, DIFF_RESET);
1497                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1498                         line, reset,
1499                         strchr(line, ' ') ? "\t" : "");
1500                 break;
1501         case DIFF_SYMBOL_BINARY_FILES:
1502         case DIFF_SYMBOL_HEADER:
1503                 fprintf(o->file, "%s", line);
1504                 break;
1505         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1506                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1507                 break;
1508         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1509                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1510                 break;
1511         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1512                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1513                 break;
1514         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1515                 fputs(diff_line_prefix(o), o->file);
1516                 fputc('\n', o->file);
1517                 break;
1518         case DIFF_SYMBOL_REWRITE_DIFF:
1519                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1520                 reset = diff_get_color_opt(o, DIFF_RESET);
1521                 emit_line(o, fraginfo, reset, line, len);
1522                 break;
1523         case DIFF_SYMBOL_SUBMODULE_ADD:
1524                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1525                 reset = diff_get_color_opt(o, DIFF_RESET);
1526                 emit_line(o, set, reset, line, len);
1527                 break;
1528         case DIFF_SYMBOL_SUBMODULE_DEL:
1529                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1530                 reset = diff_get_color_opt(o, DIFF_RESET);
1531                 emit_line(o, set, reset, line, len);
1532                 break;
1533         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1534                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1535                         diff_line_prefix(o), line);
1536                 break;
1537         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1538                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1539                         diff_line_prefix(o), line);
1540                 break;
1541         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1542                 emit_line(o, "", "", " 0 files changed\n",
1543                           strlen(" 0 files changed\n"));
1544                 break;
1545         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1546                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1547                 break;
1548         case DIFF_SYMBOL_WORD_DIFF:
1549                 fprintf(o->file, "%.*s", len, line);
1550                 break;
1551         case DIFF_SYMBOL_STAT_SEP:
1552                 fputs(o->stat_sep, o->file);
1553                 break;
1554         default:
1555                 BUG("unknown diff symbol");
1556         }
1557         strbuf_release(&sb);
1558 }
1559
1560 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1561                              const char *line, int len, unsigned flags)
1562 {
1563         struct emitted_diff_symbol e = {line, len, flags, 0, 0, s};
1564
1565         if (o->emitted_symbols)
1566                 append_emitted_diff_symbol(o, &e);
1567         else
1568                 emit_diff_symbol_from_struct(o, &e);
1569 }
1570
1571 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1572 {
1573         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1574 }
1575
1576 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1577 {
1578         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1579 }
1580
1581 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1582 {
1583         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1584                          path, strlen(path), 0);
1585 }
1586
1587 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1588 {
1589         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1590                          path, strlen(path), 0);
1591 }
1592
1593 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1594 {
1595         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1596                          header, strlen(header), 0);
1597 }
1598
1599 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1600 {
1601         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1602 }
1603
1604 void diff_emit_submodule_pipethrough(struct diff_options *o,
1605                                      const char *line, int len)
1606 {
1607         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1608 }
1609
1610 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1611 {
1612         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1613               ecbdata->blank_at_eof_in_preimage &&
1614               ecbdata->blank_at_eof_in_postimage &&
1615               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1616               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1617                 return 0;
1618         return ws_blank_line(line, len, ecbdata->ws_rule);
1619 }
1620
1621 static void emit_add_line(struct emit_callback *ecbdata,
1622                           const char *line, int len)
1623 {
1624         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1625         if (new_blank_line_at_eof(ecbdata, line, len))
1626                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1627
1628         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1629 }
1630
1631 static void emit_del_line(struct emit_callback *ecbdata,
1632                           const char *line, int len)
1633 {
1634         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1635         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1636 }
1637
1638 static void emit_context_line(struct emit_callback *ecbdata,
1639                               const char *line, int len)
1640 {
1641         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1642         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1643 }
1644
1645 static void emit_hunk_header(struct emit_callback *ecbdata,
1646                              const char *line, int len)
1647 {
1648         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1649         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1650         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1651         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1652         const char *reverse = ecbdata->color_diff ? GIT_COLOR_REVERSE : "";
1653         static const char atat[2] = { '@', '@' };
1654         const char *cp, *ep;
1655         struct strbuf msgbuf = STRBUF_INIT;
1656         int org_len = len;
1657         int i = 1;
1658
1659         /*
1660          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1661          * it always is at least 10 bytes long.
1662          */
1663         if (len < 10 ||
1664             memcmp(line, atat, 2) ||
1665             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1666                 emit_diff_symbol(ecbdata->opt,
1667                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1668                 return;
1669         }
1670         ep += 2; /* skip over @@ */
1671
1672         /* The hunk header in fraginfo color */
1673         if (ecbdata->opt->flags.dual_color_diffed_diffs)
1674                 strbuf_addstr(&msgbuf, reverse);
1675         strbuf_addstr(&msgbuf, frag);
1676         if (ecbdata->opt->flags.suppress_hunk_header_line_count)
1677                 strbuf_add(&msgbuf, atat, sizeof(atat));
1678         else
1679                 strbuf_add(&msgbuf, line, ep - line);
1680         strbuf_addstr(&msgbuf, reset);
1681
1682         /*
1683          * trailing "\r\n"
1684          */
1685         for ( ; i < 3; i++)
1686                 if (line[len - i] == '\r' || line[len - i] == '\n')
1687                         len--;
1688
1689         /* blank before the func header */
1690         for (cp = ep; ep - line < len; ep++)
1691                 if (*ep != ' ' && *ep != '\t')
1692                         break;
1693         if (ep != cp) {
1694                 strbuf_addstr(&msgbuf, context);
1695                 strbuf_add(&msgbuf, cp, ep - cp);
1696                 strbuf_addstr(&msgbuf, reset);
1697         }
1698
1699         if (ep < line + len) {
1700                 strbuf_addstr(&msgbuf, func);
1701                 strbuf_add(&msgbuf, ep, line + len - ep);
1702                 strbuf_addstr(&msgbuf, reset);
1703         }
1704
1705         strbuf_add(&msgbuf, line + len, org_len - len);
1706         strbuf_complete_line(&msgbuf);
1707         emit_diff_symbol(ecbdata->opt,
1708                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1709         strbuf_release(&msgbuf);
1710 }
1711
1712 static struct diff_tempfile *claim_diff_tempfile(void)
1713 {
1714         int i;
1715         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1716                 if (!diff_temp[i].name)
1717                         return diff_temp + i;
1718         BUG("diff is failing to clean up its tempfiles");
1719 }
1720
1721 static void remove_tempfile(void)
1722 {
1723         int i;
1724         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1725                 if (is_tempfile_active(diff_temp[i].tempfile))
1726                         delete_tempfile(&diff_temp[i].tempfile);
1727                 diff_temp[i].name = NULL;
1728         }
1729 }
1730
1731 static void add_line_count(struct strbuf *out, int count)
1732 {
1733         switch (count) {
1734         case 0:
1735                 strbuf_addstr(out, "0,0");
1736                 break;
1737         case 1:
1738                 strbuf_addstr(out, "1");
1739                 break;
1740         default:
1741                 strbuf_addf(out, "1,%d", count);
1742                 break;
1743         }
1744 }
1745
1746 static void emit_rewrite_lines(struct emit_callback *ecb,
1747                                int prefix, const char *data, int size)
1748 {
1749         const char *endp = NULL;
1750
1751         while (0 < size) {
1752                 int len;
1753
1754                 endp = memchr(data, '\n', size);
1755                 len = endp ? (endp - data + 1) : size;
1756                 if (prefix != '+') {
1757                         ecb->lno_in_preimage++;
1758                         emit_del_line(ecb, data, len);
1759                 } else {
1760                         ecb->lno_in_postimage++;
1761                         emit_add_line(ecb, data, len);
1762                 }
1763                 size -= len;
1764                 data += len;
1765         }
1766         if (!endp)
1767                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1768 }
1769
1770 static void emit_rewrite_diff(const char *name_a,
1771                               const char *name_b,
1772                               struct diff_filespec *one,
1773                               struct diff_filespec *two,
1774                               struct userdiff_driver *textconv_one,
1775                               struct userdiff_driver *textconv_two,
1776                               struct diff_options *o)
1777 {
1778         int lc_a, lc_b;
1779         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1780         const char *a_prefix, *b_prefix;
1781         char *data_one, *data_two;
1782         size_t size_one, size_two;
1783         struct emit_callback ecbdata;
1784         struct strbuf out = STRBUF_INIT;
1785
1786         if (diff_mnemonic_prefix && o->flags.reverse_diff) {
1787                 a_prefix = o->b_prefix;
1788                 b_prefix = o->a_prefix;
1789         } else {
1790                 a_prefix = o->a_prefix;
1791                 b_prefix = o->b_prefix;
1792         }
1793
1794         name_a += (*name_a == '/');
1795         name_b += (*name_b == '/');
1796
1797         strbuf_reset(&a_name);
1798         strbuf_reset(&b_name);
1799         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1800         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1801
1802         size_one = fill_textconv(o->repo, textconv_one, one, &data_one);
1803         size_two = fill_textconv(o->repo, textconv_two, two, &data_two);
1804
1805         memset(&ecbdata, 0, sizeof(ecbdata));
1806         ecbdata.color_diff = want_color(o->use_color);
1807         ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
1808         ecbdata.opt = o;
1809         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1810                 mmfile_t mf1, mf2;
1811                 mf1.ptr = (char *)data_one;
1812                 mf2.ptr = (char *)data_two;
1813                 mf1.size = size_one;
1814                 mf2.size = size_two;
1815                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1816         }
1817         ecbdata.lno_in_preimage = 1;
1818         ecbdata.lno_in_postimage = 1;
1819
1820         lc_a = count_lines(data_one, size_one);
1821         lc_b = count_lines(data_two, size_two);
1822
1823         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1824                          a_name.buf, a_name.len, 0);
1825         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1826                          b_name.buf, b_name.len, 0);
1827
1828         strbuf_addstr(&out, "@@ -");
1829         if (!o->irreversible_delete)
1830                 add_line_count(&out, lc_a);
1831         else
1832                 strbuf_addstr(&out, "?,?");
1833         strbuf_addstr(&out, " +");
1834         add_line_count(&out, lc_b);
1835         strbuf_addstr(&out, " @@\n");
1836         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1837         strbuf_release(&out);
1838
1839         if (lc_a && !o->irreversible_delete)
1840                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1841         if (lc_b)
1842                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1843         if (textconv_one)
1844                 free((char *)data_one);
1845         if (textconv_two)
1846                 free((char *)data_two);
1847 }
1848
1849 struct diff_words_buffer {
1850         mmfile_t text;
1851         unsigned long alloc;
1852         struct diff_words_orig {
1853                 const char *begin, *end;
1854         } *orig;
1855         int orig_nr, orig_alloc;
1856 };
1857
1858 static void diff_words_append(char *line, unsigned long len,
1859                 struct diff_words_buffer *buffer)
1860 {
1861         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1862         line++;
1863         len--;
1864         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1865         buffer->text.size += len;
1866         buffer->text.ptr[buffer->text.size] = '\0';
1867 }
1868
1869 struct diff_words_style_elem {
1870         const char *prefix;
1871         const char *suffix;
1872         const char *color; /* NULL; filled in by the setup code if
1873                             * color is enabled */
1874 };
1875
1876 struct diff_words_style {
1877         enum diff_words_type type;
1878         struct diff_words_style_elem new_word, old_word, ctx;
1879         const char *newline;
1880 };
1881
1882 static struct diff_words_style diff_words_styles[] = {
1883         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1884         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1885         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1886 };
1887
1888 struct diff_words_data {
1889         struct diff_words_buffer minus, plus;
1890         const char *current_plus;
1891         int last_minus;
1892         struct diff_options *opt;
1893         regex_t *word_regex;
1894         enum diff_words_type type;
1895         struct diff_words_style *style;
1896 };
1897
1898 static int fn_out_diff_words_write_helper(struct diff_options *o,
1899                                           struct diff_words_style_elem *st_el,
1900                                           const char *newline,
1901                                           size_t count, const char *buf)
1902 {
1903         int print = 0;
1904         struct strbuf sb = STRBUF_INIT;
1905
1906         while (count) {
1907                 char *p = memchr(buf, '\n', count);
1908                 if (print)
1909                         strbuf_addstr(&sb, diff_line_prefix(o));
1910
1911                 if (p != buf) {
1912                         const char *reset = st_el->color && *st_el->color ?
1913                                             GIT_COLOR_RESET : NULL;
1914                         if (st_el->color && *st_el->color)
1915                                 strbuf_addstr(&sb, st_el->color);
1916                         strbuf_addstr(&sb, st_el->prefix);
1917                         strbuf_add(&sb, buf, p ? p - buf : count);
1918                         strbuf_addstr(&sb, st_el->suffix);
1919                         if (reset)
1920                                 strbuf_addstr(&sb, reset);
1921                 }
1922                 if (!p)
1923                         goto out;
1924
1925                 strbuf_addstr(&sb, newline);
1926                 count -= p + 1 - buf;
1927                 buf = p + 1;
1928                 print = 1;
1929                 if (count) {
1930                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1931                                          sb.buf, sb.len, 0);
1932                         strbuf_reset(&sb);
1933                 }
1934         }
1935
1936 out:
1937         if (sb.len)
1938                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1939                                  sb.buf, sb.len, 0);
1940         strbuf_release(&sb);
1941         return 0;
1942 }
1943
1944 /*
1945  * '--color-words' algorithm can be described as:
1946  *
1947  *   1. collect the minus/plus lines of a diff hunk, divided into
1948  *      minus-lines and plus-lines;
1949  *
1950  *   2. break both minus-lines and plus-lines into words and
1951  *      place them into two mmfile_t with one word for each line;
1952  *
1953  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1954  *
1955  * And for the common parts of the both file, we output the plus side text.
1956  * diff_words->current_plus is used to trace the current position of the plus file
1957  * which printed. diff_words->last_minus is used to trace the last minus word
1958  * printed.
1959  *
1960  * For '--graph' to work with '--color-words', we need to output the graph prefix
1961  * on each line of color words output. Generally, there are two conditions on
1962  * which we should output the prefix.
1963  *
1964  *   1. diff_words->last_minus == 0 &&
1965  *      diff_words->current_plus == diff_words->plus.text.ptr
1966  *
1967  *      that is: the plus text must start as a new line, and if there is no minus
1968  *      word printed, a graph prefix must be printed.
1969  *
1970  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1971  *      *(diff_words->current_plus - 1) == '\n'
1972  *
1973  *      that is: a graph prefix must be printed following a '\n'
1974  */
1975 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1976 {
1977         if ((diff_words->last_minus == 0 &&
1978                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1979                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1980                 *(diff_words->current_plus - 1) == '\n')) {
1981                 return 1;
1982         } else {
1983                 return 0;
1984         }
1985 }
1986
1987 static void fn_out_diff_words_aux(void *priv,
1988                                   long minus_first, long minus_len,
1989                                   long plus_first, long plus_len,
1990                                   const char *func, long funclen)
1991 {
1992         struct diff_words_data *diff_words = priv;
1993         struct diff_words_style *style = diff_words->style;
1994         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1995         struct diff_options *opt = diff_words->opt;
1996         const char *line_prefix;
1997
1998         assert(opt);
1999         line_prefix = diff_line_prefix(opt);
2000
2001         /* POSIX requires that first be decremented by one if len == 0... */
2002         if (minus_len) {
2003                 minus_begin = diff_words->minus.orig[minus_first].begin;
2004                 minus_end =
2005                         diff_words->minus.orig[minus_first + minus_len - 1].end;
2006         } else
2007                 minus_begin = minus_end =
2008                         diff_words->minus.orig[minus_first].end;
2009
2010         if (plus_len) {
2011                 plus_begin = diff_words->plus.orig[plus_first].begin;
2012                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
2013         } else
2014                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
2015
2016         if (color_words_output_graph_prefix(diff_words)) {
2017                 fputs(line_prefix, diff_words->opt->file);
2018         }
2019         if (diff_words->current_plus != plus_begin) {
2020                 fn_out_diff_words_write_helper(diff_words->opt,
2021                                 &style->ctx, style->newline,
2022                                 plus_begin - diff_words->current_plus,
2023                                 diff_words->current_plus);
2024         }
2025         if (minus_begin != minus_end) {
2026                 fn_out_diff_words_write_helper(diff_words->opt,
2027                                 &style->old_word, style->newline,
2028                                 minus_end - minus_begin, minus_begin);
2029         }
2030         if (plus_begin != plus_end) {
2031                 fn_out_diff_words_write_helper(diff_words->opt,
2032                                 &style->new_word, style->newline,
2033                                 plus_end - plus_begin, plus_begin);
2034         }
2035
2036         diff_words->current_plus = plus_end;
2037         diff_words->last_minus = minus_first;
2038 }
2039
2040 /* This function starts looking at *begin, and returns 0 iff a word was found. */
2041 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
2042                 int *begin, int *end)
2043 {
2044         if (word_regex && *begin < buffer->size) {
2045                 regmatch_t match[1];
2046                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
2047                                  buffer->size - *begin, 1, match, 0)) {
2048                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
2049                                         '\n', match[0].rm_eo - match[0].rm_so);
2050                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
2051                         *begin += match[0].rm_so;
2052                         return *begin >= *end;
2053                 }
2054                 return -1;
2055         }
2056
2057         /* find the next word */
2058         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
2059                 (*begin)++;
2060         if (*begin >= buffer->size)
2061                 return -1;
2062
2063         /* find the end of the word */
2064         *end = *begin + 1;
2065         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
2066                 (*end)++;
2067
2068         return 0;
2069 }
2070
2071 /*
2072  * This function splits the words in buffer->text, stores the list with
2073  * newline separator into out, and saves the offsets of the original words
2074  * in buffer->orig.
2075  */
2076 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
2077                 regex_t *word_regex)
2078 {
2079         int i, j;
2080         long alloc = 0;
2081
2082         out->size = 0;
2083         out->ptr = NULL;
2084
2085         /* fake an empty "0th" word */
2086         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
2087         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
2088         buffer->orig_nr = 1;
2089
2090         for (i = 0; i < buffer->text.size; i++) {
2091                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
2092                         return;
2093
2094                 /* store original boundaries */
2095                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
2096                                 buffer->orig_alloc);
2097                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
2098                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
2099                 buffer->orig_nr++;
2100
2101                 /* store one word */
2102                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
2103                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
2104                 out->ptr[out->size + j - i] = '\n';
2105                 out->size += j - i + 1;
2106
2107                 i = j - 1;
2108         }
2109 }
2110
2111 /* this executes the word diff on the accumulated buffers */
2112 static void diff_words_show(struct diff_words_data *diff_words)
2113 {
2114         xpparam_t xpp;
2115         xdemitconf_t xecfg;
2116         mmfile_t minus, plus;
2117         struct diff_words_style *style = diff_words->style;
2118
2119         struct diff_options *opt = diff_words->opt;
2120         const char *line_prefix;
2121
2122         assert(opt);
2123         line_prefix = diff_line_prefix(opt);
2124
2125         /* special case: only removal */
2126         if (!diff_words->plus.text.size) {
2127                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2128                                  line_prefix, strlen(line_prefix), 0);
2129                 fn_out_diff_words_write_helper(diff_words->opt,
2130                         &style->old_word, style->newline,
2131                         diff_words->minus.text.size,
2132                         diff_words->minus.text.ptr);
2133                 diff_words->minus.text.size = 0;
2134                 return;
2135         }
2136
2137         diff_words->current_plus = diff_words->plus.text.ptr;
2138         diff_words->last_minus = 0;
2139
2140         memset(&xpp, 0, sizeof(xpp));
2141         memset(&xecfg, 0, sizeof(xecfg));
2142         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
2143         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
2144         xpp.flags = 0;
2145         /* as only the hunk header will be parsed, we need a 0-context */
2146         xecfg.ctxlen = 0;
2147         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, NULL,
2148                           diff_words, &xpp, &xecfg))
2149                 die("unable to generate word diff");
2150         free(minus.ptr);
2151         free(plus.ptr);
2152         if (diff_words->current_plus != diff_words->plus.text.ptr +
2153                         diff_words->plus.text.size) {
2154                 if (color_words_output_graph_prefix(diff_words))
2155                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2156                                          line_prefix, strlen(line_prefix), 0);
2157                 fn_out_diff_words_write_helper(diff_words->opt,
2158                         &style->ctx, style->newline,
2159                         diff_words->plus.text.ptr + diff_words->plus.text.size
2160                         - diff_words->current_plus, diff_words->current_plus);
2161         }
2162         diff_words->minus.text.size = diff_words->plus.text.size = 0;
2163 }
2164
2165 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
2166 static void diff_words_flush(struct emit_callback *ecbdata)
2167 {
2168         struct diff_options *wo = ecbdata->diff_words->opt;
2169
2170         if (ecbdata->diff_words->minus.text.size ||
2171             ecbdata->diff_words->plus.text.size)
2172                 diff_words_show(ecbdata->diff_words);
2173
2174         if (wo->emitted_symbols) {
2175                 struct diff_options *o = ecbdata->opt;
2176                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
2177                 int i;
2178
2179                 /*
2180                  * NEEDSWORK:
2181                  * Instead of appending each, concat all words to a line?
2182                  */
2183                 for (i = 0; i < wol->nr; i++)
2184                         append_emitted_diff_symbol(o, &wol->buf[i]);
2185
2186                 for (i = 0; i < wol->nr; i++)
2187                         free((void *)wol->buf[i].line);
2188
2189                 wol->nr = 0;
2190         }
2191 }
2192
2193 static void diff_filespec_load_driver(struct diff_filespec *one,
2194                                       struct index_state *istate)
2195 {
2196         /* Use already-loaded driver */
2197         if (one->driver)
2198                 return;
2199
2200         if (S_ISREG(one->mode))
2201                 one->driver = userdiff_find_by_path(istate, one->path);
2202
2203         /* Fallback to default settings */
2204         if (!one->driver)
2205                 one->driver = userdiff_find_by_name("default");
2206 }
2207
2208 static const char *userdiff_word_regex(struct diff_filespec *one,
2209                                        struct index_state *istate)
2210 {
2211         diff_filespec_load_driver(one, istate);
2212         return one->driver->word_regex;
2213 }
2214
2215 static void init_diff_words_data(struct emit_callback *ecbdata,
2216                                  struct diff_options *orig_opts,
2217                                  struct diff_filespec *one,
2218                                  struct diff_filespec *two)
2219 {
2220         int i;
2221         struct diff_options *o = xmalloc(sizeof(struct diff_options));
2222         memcpy(o, orig_opts, sizeof(struct diff_options));
2223
2224         ecbdata->diff_words =
2225                 xcalloc(1, sizeof(struct diff_words_data));
2226         ecbdata->diff_words->type = o->word_diff;
2227         ecbdata->diff_words->opt = o;
2228
2229         if (orig_opts->emitted_symbols)
2230                 o->emitted_symbols =
2231                         xcalloc(1, sizeof(struct emitted_diff_symbols));
2232
2233         if (!o->word_regex)
2234                 o->word_regex = userdiff_word_regex(one, o->repo->index);
2235         if (!o->word_regex)
2236                 o->word_regex = userdiff_word_regex(two, o->repo->index);
2237         if (!o->word_regex)
2238                 o->word_regex = diff_word_regex_cfg;
2239         if (o->word_regex) {
2240                 ecbdata->diff_words->word_regex = (regex_t *)
2241                         xmalloc(sizeof(regex_t));
2242                 if (regcomp(ecbdata->diff_words->word_regex,
2243                             o->word_regex,
2244                             REG_EXTENDED | REG_NEWLINE))
2245                         die("invalid regular expression: %s",
2246                             o->word_regex);
2247         }
2248         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2249                 if (o->word_diff == diff_words_styles[i].type) {
2250                         ecbdata->diff_words->style =
2251                                 &diff_words_styles[i];
2252                         break;
2253                 }
2254         }
2255         if (want_color(o->use_color)) {
2256                 struct diff_words_style *st = ecbdata->diff_words->style;
2257                 st->old_word.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2258                 st->new_word.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2259                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
2260         }
2261 }
2262
2263 static void free_diff_words_data(struct emit_callback *ecbdata)
2264 {
2265         if (ecbdata->diff_words) {
2266                 diff_words_flush(ecbdata);
2267                 free (ecbdata->diff_words->opt->emitted_symbols);
2268                 free (ecbdata->diff_words->opt);
2269                 free (ecbdata->diff_words->minus.text.ptr);
2270                 free (ecbdata->diff_words->minus.orig);
2271                 free (ecbdata->diff_words->plus.text.ptr);
2272                 free (ecbdata->diff_words->plus.orig);
2273                 if (ecbdata->diff_words->word_regex) {
2274                         regfree(ecbdata->diff_words->word_regex);
2275                         free(ecbdata->diff_words->word_regex);
2276                 }
2277                 FREE_AND_NULL(ecbdata->diff_words);
2278         }
2279 }
2280
2281 const char *diff_get_color(int diff_use_color, enum color_diff ix)
2282 {
2283         if (want_color(diff_use_color))
2284                 return diff_colors[ix];
2285         return "";
2286 }
2287
2288 const char *diff_line_prefix(struct diff_options *opt)
2289 {
2290         struct strbuf *msgbuf;
2291         if (!opt->output_prefix)
2292                 return "";
2293
2294         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
2295         return msgbuf->buf;
2296 }
2297
2298 static unsigned long sane_truncate_line(char *line, unsigned long len)
2299 {
2300         const char *cp;
2301         unsigned long allot;
2302         size_t l = len;
2303
2304         cp = line;
2305         allot = l;
2306         while (0 < l) {
2307                 (void) utf8_width(&cp, &l);
2308                 if (!cp)
2309                         break; /* truncated in the middle? */
2310         }
2311         return allot - l;
2312 }
2313
2314 static void find_lno(const char *line, struct emit_callback *ecbdata)
2315 {
2316         const char *p;
2317         ecbdata->lno_in_preimage = 0;
2318         ecbdata->lno_in_postimage = 0;
2319         p = strchr(line, '-');
2320         if (!p)
2321                 return; /* cannot happen */
2322         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
2323         p = strchr(p, '+');
2324         if (!p)
2325                 return; /* cannot happen */
2326         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
2327 }
2328
2329 static void fn_out_consume(void *priv, char *line, unsigned long len)
2330 {
2331         struct emit_callback *ecbdata = priv;
2332         struct diff_options *o = ecbdata->opt;
2333
2334         o->found_changes = 1;
2335
2336         if (ecbdata->header) {
2337                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2338                                  ecbdata->header->buf, ecbdata->header->len, 0);
2339                 strbuf_reset(ecbdata->header);
2340                 ecbdata->header = NULL;
2341         }
2342
2343         if (ecbdata->label_path[0]) {
2344                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
2345                                  ecbdata->label_path[0],
2346                                  strlen(ecbdata->label_path[0]), 0);
2347                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
2348                                  ecbdata->label_path[1],
2349                                  strlen(ecbdata->label_path[1]), 0);
2350                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
2351         }
2352
2353         if (diff_suppress_blank_empty
2354             && len == 2 && line[0] == ' ' && line[1] == '\n') {
2355                 line[0] = '\n';
2356                 len = 1;
2357         }
2358
2359         if (line[0] == '@') {
2360                 if (ecbdata->diff_words)
2361                         diff_words_flush(ecbdata);
2362                 len = sane_truncate_line(line, len);
2363                 find_lno(line, ecbdata);
2364                 emit_hunk_header(ecbdata, line, len);
2365                 return;
2366         }
2367
2368         if (ecbdata->diff_words) {
2369                 enum diff_symbol s =
2370                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2371                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2372                 if (line[0] == '-') {
2373                         diff_words_append(line, len,
2374                                           &ecbdata->diff_words->minus);
2375                         return;
2376                 } else if (line[0] == '+') {
2377                         diff_words_append(line, len,
2378                                           &ecbdata->diff_words->plus);
2379                         return;
2380                 } else if (starts_with(line, "\\ ")) {
2381                         /*
2382                          * Eat the "no newline at eof" marker as if we
2383                          * saw a "+" or "-" line with nothing on it,
2384                          * and return without diff_words_flush() to
2385                          * defer processing. If this is the end of
2386                          * preimage, more "+" lines may come after it.
2387                          */
2388                         return;
2389                 }
2390                 diff_words_flush(ecbdata);
2391                 emit_diff_symbol(o, s, line, len, 0);
2392                 return;
2393         }
2394
2395         switch (line[0]) {
2396         case '+':
2397                 ecbdata->lno_in_postimage++;
2398                 emit_add_line(ecbdata, line + 1, len - 1);
2399                 break;
2400         case '-':
2401                 ecbdata->lno_in_preimage++;
2402                 emit_del_line(ecbdata, line + 1, len - 1);
2403                 break;
2404         case ' ':
2405                 ecbdata->lno_in_postimage++;
2406                 ecbdata->lno_in_preimage++;
2407                 emit_context_line(ecbdata, line + 1, len - 1);
2408                 break;
2409         default:
2410                 /* incomplete line at the end */
2411                 ecbdata->lno_in_preimage++;
2412                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2413                                  line, len, 0);
2414                 break;
2415         }
2416 }
2417
2418 static void pprint_rename(struct strbuf *name, const char *a, const char *b)
2419 {
2420         const char *old_name = a;
2421         const char *new_name = b;
2422         int pfx_length, sfx_length;
2423         int pfx_adjust_for_slash;
2424         int len_a = strlen(a);
2425         int len_b = strlen(b);
2426         int a_midlen, b_midlen;
2427         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2428         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2429
2430         if (qlen_a || qlen_b) {
2431                 quote_c_style(a, name, NULL, 0);
2432                 strbuf_addstr(name, " => ");
2433                 quote_c_style(b, name, NULL, 0);
2434                 return;
2435         }
2436
2437         /* Find common prefix */
2438         pfx_length = 0;
2439         while (*old_name && *new_name && *old_name == *new_name) {
2440                 if (*old_name == '/')
2441                         pfx_length = old_name - a + 1;
2442                 old_name++;
2443                 new_name++;
2444         }
2445
2446         /* Find common suffix */
2447         old_name = a + len_a;
2448         new_name = b + len_b;
2449         sfx_length = 0;
2450         /*
2451          * If there is a common prefix, it must end in a slash.  In
2452          * that case we let this loop run 1 into the prefix to see the
2453          * same slash.
2454          *
2455          * If there is no common prefix, we cannot do this as it would
2456          * underrun the input strings.
2457          */
2458         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2459         while (a + pfx_length - pfx_adjust_for_slash <= old_name &&
2460                b + pfx_length - pfx_adjust_for_slash <= new_name &&
2461                *old_name == *new_name) {
2462                 if (*old_name == '/')
2463                         sfx_length = len_a - (old_name - a);
2464                 old_name--;
2465                 new_name--;
2466         }
2467
2468         /*
2469          * pfx{mid-a => mid-b}sfx
2470          * {pfx-a => pfx-b}sfx
2471          * pfx{sfx-a => sfx-b}
2472          * name-a => name-b
2473          */
2474         a_midlen = len_a - pfx_length - sfx_length;
2475         b_midlen = len_b - pfx_length - sfx_length;
2476         if (a_midlen < 0)
2477                 a_midlen = 0;
2478         if (b_midlen < 0)
2479                 b_midlen = 0;
2480
2481         strbuf_grow(name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2482         if (pfx_length + sfx_length) {
2483                 strbuf_add(name, a, pfx_length);
2484                 strbuf_addch(name, '{');
2485         }
2486         strbuf_add(name, a + pfx_length, a_midlen);
2487         strbuf_addstr(name, " => ");
2488         strbuf_add(name, b + pfx_length, b_midlen);
2489         if (pfx_length + sfx_length) {
2490                 strbuf_addch(name, '}');
2491                 strbuf_add(name, a + len_a - sfx_length, sfx_length);
2492         }
2493 }
2494
2495 struct diffstat_t {
2496         int nr;
2497         int alloc;
2498         struct diffstat_file {
2499                 char *from_name;
2500                 char *name;
2501                 char *print_name;
2502                 const char *comments;
2503                 unsigned is_unmerged:1;
2504                 unsigned is_binary:1;
2505                 unsigned is_renamed:1;
2506                 unsigned is_interesting:1;
2507                 uintmax_t added, deleted;
2508         } **files;
2509 };
2510
2511 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2512                                           const char *name_a,
2513                                           const char *name_b)
2514 {
2515         struct diffstat_file *x;
2516         x = xcalloc(1, sizeof(*x));
2517         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2518         diffstat->files[diffstat->nr++] = x;
2519         if (name_b) {
2520                 x->from_name = xstrdup(name_a);
2521                 x->name = xstrdup(name_b);
2522                 x->is_renamed = 1;
2523         }
2524         else {
2525                 x->from_name = NULL;
2526                 x->name = xstrdup(name_a);
2527         }
2528         return x;
2529 }
2530
2531 static void diffstat_consume(void *priv, char *line, unsigned long len)
2532 {
2533         struct diffstat_t *diffstat = priv;
2534         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2535
2536         if (line[0] == '+')
2537                 x->added++;
2538         else if (line[0] == '-')
2539                 x->deleted++;
2540 }
2541
2542 const char mime_boundary_leader[] = "------------";
2543
2544 static int scale_linear(int it, int width, int max_change)
2545 {
2546         if (!it)
2547                 return 0;
2548         /*
2549          * make sure that at least one '-' or '+' is printed if
2550          * there is any change to this path. The easiest way is to
2551          * scale linearly as if the alloted width is one column shorter
2552          * than it is, and then add 1 to the result.
2553          */
2554         return 1 + (it * (width - 1) / max_change);
2555 }
2556
2557 static void show_graph(struct strbuf *out, char ch, int cnt,
2558                        const char *set, const char *reset)
2559 {
2560         if (cnt <= 0)
2561                 return;
2562         strbuf_addstr(out, set);
2563         strbuf_addchars(out, ch, cnt);
2564         strbuf_addstr(out, reset);
2565 }
2566
2567 static void fill_print_name(struct diffstat_file *file)
2568 {
2569         struct strbuf pname = STRBUF_INIT;
2570
2571         if (file->print_name)
2572                 return;
2573
2574         if (file->is_renamed)
2575                 pprint_rename(&pname, file->from_name, file->name);
2576         else
2577                 quote_c_style(file->name, &pname, NULL, 0);
2578
2579         if (file->comments)
2580                 strbuf_addf(&pname, " (%s)", file->comments);
2581
2582         file->print_name = strbuf_detach(&pname, NULL);
2583 }
2584
2585 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2586                 int files, int insertions, int deletions)
2587 {
2588         struct strbuf sb = STRBUF_INIT;
2589
2590         if (!files) {
2591                 assert(insertions == 0 && deletions == 0);
2592                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2593                                  NULL, 0, 0);
2594                 return;
2595         }
2596
2597         strbuf_addf(&sb,
2598                     (files == 1) ? " %d file changed" : " %d files changed",
2599                     files);
2600
2601         /*
2602          * For binary diff, the caller may want to print "x files
2603          * changed" with insertions == 0 && deletions == 0.
2604          *
2605          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2606          * is probably less confusing (i.e skip over "2 files changed
2607          * but nothing about added/removed lines? Is this a bug in Git?").
2608          */
2609         if (insertions || deletions == 0) {
2610                 strbuf_addf(&sb,
2611                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2612                             insertions);
2613         }
2614
2615         if (deletions || insertions == 0) {
2616                 strbuf_addf(&sb,
2617                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2618                             deletions);
2619         }
2620         strbuf_addch(&sb, '\n');
2621         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2622                          sb.buf, sb.len, 0);
2623         strbuf_release(&sb);
2624 }
2625
2626 void print_stat_summary(FILE *fp, int files,
2627                         int insertions, int deletions)
2628 {
2629         struct diff_options o;
2630         memset(&o, 0, sizeof(o));
2631         o.file = fp;
2632
2633         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2634 }
2635
2636 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2637 {
2638         int i, len, add, del, adds = 0, dels = 0;
2639         uintmax_t max_change = 0, max_len = 0;
2640         int total_files = data->nr, count;
2641         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2642         const char *reset, *add_c, *del_c;
2643         int extra_shown = 0;
2644         const char *line_prefix = diff_line_prefix(options);
2645         struct strbuf out = STRBUF_INIT;
2646
2647         if (data->nr == 0)
2648                 return;
2649
2650         count = options->stat_count ? options->stat_count : data->nr;
2651
2652         reset = diff_get_color_opt(options, DIFF_RESET);
2653         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2654         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2655
2656         /*
2657          * Find the longest filename and max number of changes
2658          */
2659         for (i = 0; (i < count) && (i < data->nr); i++) {
2660                 struct diffstat_file *file = data->files[i];
2661                 uintmax_t change = file->added + file->deleted;
2662
2663                 if (!file->is_interesting && (change == 0)) {
2664                         count++; /* not shown == room for one more */
2665                         continue;
2666                 }
2667                 fill_print_name(file);
2668                 len = strlen(file->print_name);
2669                 if (max_len < len)
2670                         max_len = len;
2671
2672                 if (file->is_unmerged) {
2673                         /* "Unmerged" is 8 characters */
2674                         bin_width = bin_width < 8 ? 8 : bin_width;
2675                         continue;
2676                 }
2677                 if (file->is_binary) {
2678                         /* "Bin XXX -> YYY bytes" */
2679                         int w = 14 + decimal_width(file->added)
2680                                 + decimal_width(file->deleted);
2681                         bin_width = bin_width < w ? w : bin_width;
2682                         /* Display change counts aligned with "Bin" */
2683                         number_width = 3;
2684                         continue;
2685                 }
2686
2687                 if (max_change < change)
2688                         max_change = change;
2689         }
2690         count = i; /* where we can stop scanning in data->files[] */
2691
2692         /*
2693          * We have width = stat_width or term_columns() columns total.
2694          * We want a maximum of min(max_len, stat_name_width) for the name part.
2695          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2696          * We also need 1 for " " and 4 + decimal_width(max_change)
2697          * for " | NNNN " and one the empty column at the end, altogether
2698          * 6 + decimal_width(max_change).
2699          *
2700          * If there's not enough space, we will use the smaller of
2701          * stat_name_width (if set) and 5/8*width for the filename,
2702          * and the rest for constant elements + graph part, but no more
2703          * than stat_graph_width for the graph part.
2704          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2705          * for the standard terminal size).
2706          *
2707          * In other words: stat_width limits the maximum width, and
2708          * stat_name_width fixes the maximum width of the filename,
2709          * and is also used to divide available columns if there
2710          * aren't enough.
2711          *
2712          * Binary files are displayed with "Bin XXX -> YYY bytes"
2713          * instead of the change count and graph. This part is treated
2714          * similarly to the graph part, except that it is not
2715          * "scaled". If total width is too small to accommodate the
2716          * guaranteed minimum width of the filename part and the
2717          * separators and this message, this message will "overflow"
2718          * making the line longer than the maximum width.
2719          */
2720
2721         if (options->stat_width == -1)
2722                 width = term_columns() - strlen(line_prefix);
2723         else
2724                 width = options->stat_width ? options->stat_width : 80;
2725         number_width = decimal_width(max_change) > number_width ?
2726                 decimal_width(max_change) : number_width;
2727
2728         if (options->stat_graph_width == -1)
2729                 options->stat_graph_width = diff_stat_graph_width;
2730
2731         /*
2732          * Guarantee 3/8*16==6 for the graph part
2733          * and 5/8*16==10 for the filename part
2734          */
2735         if (width < 16 + 6 + number_width)
2736                 width = 16 + 6 + number_width;
2737
2738         /*
2739          * First assign sizes that are wanted, ignoring available width.
2740          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2741          * starting from "XXX" should fit in graph_width.
2742          */
2743         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2744         if (options->stat_graph_width &&
2745             options->stat_graph_width < graph_width)
2746                 graph_width = options->stat_graph_width;
2747
2748         name_width = (options->stat_name_width > 0 &&
2749                       options->stat_name_width < max_len) ?
2750                 options->stat_name_width : max_len;
2751
2752         /*
2753          * Adjust adjustable widths not to exceed maximum width
2754          */
2755         if (name_width + number_width + 6 + graph_width > width) {
2756                 if (graph_width > width * 3/8 - number_width - 6) {
2757                         graph_width = width * 3/8 - number_width - 6;
2758                         if (graph_width < 6)
2759                                 graph_width = 6;
2760                 }
2761
2762                 if (options->stat_graph_width &&
2763                     graph_width > options->stat_graph_width)
2764                         graph_width = options->stat_graph_width;
2765                 if (name_width > width - number_width - 6 - graph_width)
2766                         name_width = width - number_width - 6 - graph_width;
2767                 else
2768                         graph_width = width - number_width - 6 - name_width;
2769         }
2770
2771         /*
2772          * From here name_width is the width of the name area,
2773          * and graph_width is the width of the graph area.
2774          * max_change is used to scale graph properly.
2775          */
2776         for (i = 0; i < count; i++) {
2777                 const char *prefix = "";
2778                 struct diffstat_file *file = data->files[i];
2779                 char *name = file->print_name;
2780                 uintmax_t added = file->added;
2781                 uintmax_t deleted = file->deleted;
2782                 int name_len;
2783
2784                 if (!file->is_interesting && (added + deleted == 0))
2785                         continue;
2786
2787                 /*
2788                  * "scale" the filename
2789                  */
2790                 len = name_width;
2791                 name_len = strlen(name);
2792                 if (name_width < name_len) {
2793                         char *slash;
2794                         prefix = "...";
2795                         len -= 3;
2796                         name += name_len - len;
2797                         slash = strchr(name, '/');
2798                         if (slash)
2799                                 name = slash;
2800                 }
2801
2802                 if (file->is_binary) {
2803                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2804                         strbuf_addf(&out, " %*s", number_width, "Bin");
2805                         if (!added && !deleted) {
2806                                 strbuf_addch(&out, '\n');
2807                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2808                                                  out.buf, out.len, 0);
2809                                 strbuf_reset(&out);
2810                                 continue;
2811                         }
2812                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2813                                 del_c, deleted, reset);
2814                         strbuf_addstr(&out, " -> ");
2815                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2816                                 add_c, added, reset);
2817                         strbuf_addstr(&out, " bytes\n");
2818                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2819                                          out.buf, out.len, 0);
2820                         strbuf_reset(&out);
2821                         continue;
2822                 }
2823                 else if (file->is_unmerged) {
2824                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2825                         strbuf_addstr(&out, " Unmerged\n");
2826                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2827                                          out.buf, out.len, 0);
2828                         strbuf_reset(&out);
2829                         continue;
2830                 }
2831
2832                 /*
2833                  * scale the add/delete
2834                  */
2835                 add = added;
2836                 del = deleted;
2837
2838                 if (graph_width <= max_change) {
2839                         int total = scale_linear(add + del, graph_width, max_change);
2840                         if (total < 2 && add && del)
2841                                 /* width >= 2 due to the sanity check */
2842                                 total = 2;
2843                         if (add < del) {
2844                                 add = scale_linear(add, graph_width, max_change);
2845                                 del = total - add;
2846                         } else {
2847                                 del = scale_linear(del, graph_width, max_change);
2848                                 add = total - del;
2849                         }
2850                 }
2851                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2852                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2853                         number_width, added + deleted,
2854                         added + deleted ? " " : "");
2855                 show_graph(&out, '+', add, add_c, reset);
2856                 show_graph(&out, '-', del, del_c, reset);
2857                 strbuf_addch(&out, '\n');
2858                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2859                                  out.buf, out.len, 0);
2860                 strbuf_reset(&out);
2861         }
2862
2863         for (i = 0; i < data->nr; i++) {
2864                 struct diffstat_file *file = data->files[i];
2865                 uintmax_t added = file->added;
2866                 uintmax_t deleted = file->deleted;
2867
2868                 if (file->is_unmerged ||
2869                     (!file->is_interesting && (added + deleted == 0))) {
2870                         total_files--;
2871                         continue;
2872                 }
2873
2874                 if (!file->is_binary) {
2875                         adds += added;
2876                         dels += deleted;
2877                 }
2878                 if (i < count)
2879                         continue;
2880                 if (!extra_shown)
2881                         emit_diff_symbol(options,
2882                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2883                                          NULL, 0, 0);
2884                 extra_shown = 1;
2885         }
2886
2887         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2888         strbuf_release(&out);
2889 }
2890
2891 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2892 {
2893         int i, adds = 0, dels = 0, total_files = data->nr;
2894
2895         if (data->nr == 0)
2896                 return;
2897
2898         for (i = 0; i < data->nr; i++) {
2899                 int added = data->files[i]->added;
2900                 int deleted = data->files[i]->deleted;
2901
2902                 if (data->files[i]->is_unmerged ||
2903                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2904                         total_files--;
2905                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2906                         adds += added;
2907                         dels += deleted;
2908                 }
2909         }
2910         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2911 }
2912
2913 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2914 {
2915         int i;
2916
2917         if (data->nr == 0)
2918                 return;
2919
2920         for (i = 0; i < data->nr; i++) {
2921                 struct diffstat_file *file = data->files[i];
2922
2923                 fprintf(options->file, "%s", diff_line_prefix(options));
2924
2925                 if (file->is_binary)
2926                         fprintf(options->file, "-\t-\t");
2927                 else
2928                         fprintf(options->file,
2929                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2930                                 file->added, file->deleted);
2931                 if (options->line_termination) {
2932                         fill_print_name(file);
2933                         if (!file->is_renamed)
2934                                 write_name_quoted(file->name, options->file,
2935                                                   options->line_termination);
2936                         else {
2937                                 fputs(file->print_name, options->file);
2938                                 putc(options->line_termination, options->file);
2939                         }
2940                 } else {
2941                         if (file->is_renamed) {
2942                                 putc('\0', options->file);
2943                                 write_name_quoted(file->from_name, options->file, '\0');
2944                         }
2945                         write_name_quoted(file->name, options->file, '\0');
2946                 }
2947         }
2948 }
2949
2950 struct dirstat_file {
2951         const char *name;
2952         unsigned long changed;
2953 };
2954
2955 struct dirstat_dir {
2956         struct dirstat_file *files;
2957         int alloc, nr, permille, cumulative;
2958 };
2959
2960 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2961                 unsigned long changed, const char *base, int baselen)
2962 {
2963         unsigned long sum_changes = 0;
2964         unsigned int sources = 0;
2965         const char *line_prefix = diff_line_prefix(opt);
2966
2967         while (dir->nr) {
2968                 struct dirstat_file *f = dir->files;
2969                 int namelen = strlen(f->name);
2970                 unsigned long changes;
2971                 char *slash;
2972
2973                 if (namelen < baselen)
2974                         break;
2975                 if (memcmp(f->name, base, baselen))
2976                         break;
2977                 slash = strchr(f->name + baselen, '/');
2978                 if (slash) {
2979                         int newbaselen = slash + 1 - f->name;
2980                         changes = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2981                         sources++;
2982                 } else {
2983                         changes = f->changed;
2984                         dir->files++;
2985                         dir->nr--;
2986                         sources += 2;
2987                 }
2988                 sum_changes += changes;
2989         }
2990
2991         /*
2992          * We don't report dirstat's for
2993          *  - the top level
2994          *  - or cases where everything came from a single directory
2995          *    under this directory (sources == 1).
2996          */
2997         if (baselen && sources != 1) {
2998                 if (sum_changes) {
2999                         int permille = sum_changes * 1000 / changed;
3000                         if (permille >= dir->permille) {
3001                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
3002                                         permille / 10, permille % 10, baselen, base);
3003                                 if (!dir->cumulative)
3004                                         return 0;
3005                         }
3006                 }
3007         }
3008         return sum_changes;
3009 }
3010
3011 static int dirstat_compare(const void *_a, const void *_b)
3012 {
3013         const struct dirstat_file *a = _a;
3014         const struct dirstat_file *b = _b;
3015         return strcmp(a->name, b->name);
3016 }
3017
3018 static void show_dirstat(struct diff_options *options)
3019 {
3020         int i;
3021         unsigned long changed;
3022         struct dirstat_dir dir;
3023         struct diff_queue_struct *q = &diff_queued_diff;
3024
3025         dir.files = NULL;
3026         dir.alloc = 0;
3027         dir.nr = 0;
3028         dir.permille = options->dirstat_permille;
3029         dir.cumulative = options->flags.dirstat_cumulative;
3030
3031         changed = 0;
3032         for (i = 0; i < q->nr; i++) {
3033                 struct diff_filepair *p = q->queue[i];
3034                 const char *name;
3035                 unsigned long copied, added, damage;
3036
3037                 name = p->two->path ? p->two->path : p->one->path;
3038
3039                 if (p->one->oid_valid && p->two->oid_valid &&
3040                     oideq(&p->one->oid, &p->two->oid)) {
3041                         /*
3042                          * The SHA1 has not changed, so pre-/post-content is
3043                          * identical. We can therefore skip looking at the
3044                          * file contents altogether.
3045                          */
3046                         damage = 0;
3047                         goto found_damage;
3048                 }
3049
3050                 if (options->flags.dirstat_by_file) {
3051                         /*
3052                          * In --dirstat-by-file mode, we don't really need to
3053                          * look at the actual file contents at all.
3054                          * The fact that the SHA1 changed is enough for us to
3055                          * add this file to the list of results
3056                          * (with each file contributing equal damage).
3057                          */
3058                         damage = 1;
3059                         goto found_damage;
3060                 }
3061
3062                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
3063                         diff_populate_filespec(options->repo, p->one, 0);
3064                         diff_populate_filespec(options->repo, p->two, 0);
3065                         diffcore_count_changes(options->repo,
3066                                                p->one, p->two, NULL, NULL,
3067                                                &copied, &added);
3068                         diff_free_filespec_data(p->one);
3069                         diff_free_filespec_data(p->two);
3070                 } else if (DIFF_FILE_VALID(p->one)) {
3071                         diff_populate_filespec(options->repo, p->one, CHECK_SIZE_ONLY);
3072                         copied = added = 0;
3073                         diff_free_filespec_data(p->one);
3074                 } else if (DIFF_FILE_VALID(p->two)) {
3075                         diff_populate_filespec(options->repo, p->two, CHECK_SIZE_ONLY);
3076                         copied = 0;
3077                         added = p->two->size;
3078                         diff_free_filespec_data(p->two);
3079                 } else
3080                         continue;
3081
3082                 /*
3083                  * Original minus copied is the removed material,
3084                  * added is the new material.  They are both damages
3085                  * made to the preimage.
3086                  * If the resulting damage is zero, we know that
3087                  * diffcore_count_changes() considers the two entries to
3088                  * be identical, but since the oid changed, we
3089                  * know that there must have been _some_ kind of change,
3090                  * so we force all entries to have damage > 0.
3091                  */
3092                 damage = (p->one->size - copied) + added;
3093                 if (!damage)
3094                         damage = 1;
3095
3096 found_damage:
3097                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3098                 dir.files[dir.nr].name = name;
3099                 dir.files[dir.nr].changed = damage;
3100                 changed += damage;
3101                 dir.nr++;
3102         }
3103
3104         /* This can happen even with many files, if everything was renames */
3105         if (!changed)
3106                 return;
3107
3108         /* Show all directories with more than x% of the changes */
3109         QSORT(dir.files, dir.nr, dirstat_compare);
3110         gather_dirstat(options, &dir, changed, "", 0);
3111 }
3112
3113 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
3114 {
3115         int i;
3116         unsigned long changed;
3117         struct dirstat_dir dir;
3118
3119         if (data->nr == 0)
3120                 return;
3121
3122         dir.files = NULL;
3123         dir.alloc = 0;
3124         dir.nr = 0;
3125         dir.permille = options->dirstat_permille;
3126         dir.cumulative = options->flags.dirstat_cumulative;
3127
3128         changed = 0;
3129         for (i = 0; i < data->nr; i++) {
3130                 struct diffstat_file *file = data->files[i];
3131                 unsigned long damage = file->added + file->deleted;
3132                 if (file->is_binary)
3133                         /*
3134                          * binary files counts bytes, not lines. Must find some
3135                          * way to normalize binary bytes vs. textual lines.
3136                          * The following heuristic assumes that there are 64
3137                          * bytes per "line".
3138                          * This is stupid and ugly, but very cheap...
3139                          */
3140                         damage = DIV_ROUND_UP(damage, 64);
3141                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3142                 dir.files[dir.nr].name = file->name;
3143                 dir.files[dir.nr].changed = damage;
3144                 changed += damage;
3145                 dir.nr++;
3146         }
3147
3148         /* This can happen even with many files, if everything was renames */
3149         if (!changed)
3150                 return;
3151
3152         /* Show all directories with more than x% of the changes */
3153         QSORT(dir.files, dir.nr, dirstat_compare);
3154         gather_dirstat(options, &dir, changed, "", 0);
3155 }
3156
3157 static void free_diffstat_info(struct diffstat_t *diffstat)
3158 {
3159         int i;
3160         for (i = 0; i < diffstat->nr; i++) {
3161                 struct diffstat_file *f = diffstat->files[i];
3162                 free(f->print_name);
3163                 free(f->name);
3164                 free(f->from_name);
3165                 free(f);
3166         }
3167         free(diffstat->files);
3168 }
3169
3170 struct checkdiff_t {
3171         const char *filename;
3172         int lineno;
3173         int conflict_marker_size;
3174         struct diff_options *o;
3175         unsigned ws_rule;
3176         unsigned status;
3177 };
3178
3179 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
3180 {
3181         char firstchar;
3182         int cnt;
3183
3184         if (len < marker_size + 1)
3185                 return 0;
3186         firstchar = line[0];
3187         switch (firstchar) {
3188         case '=': case '>': case '<': case '|':
3189                 break;
3190         default:
3191                 return 0;
3192         }
3193         for (cnt = 1; cnt < marker_size; cnt++)
3194                 if (line[cnt] != firstchar)
3195                         return 0;
3196         /* line[1] thru line[marker_size-1] are same as firstchar */
3197         if (len < marker_size + 1 || !isspace(line[marker_size]))
3198                 return 0;
3199         return 1;
3200 }
3201
3202 static void checkdiff_consume_hunk(void *priv,
3203                                    long ob, long on, long nb, long nn,
3204                                    const char *func, long funclen)
3205
3206 {
3207         struct checkdiff_t *data = priv;
3208         data->lineno = nb - 1;
3209 }
3210
3211 static void checkdiff_consume(void *priv, char *line, unsigned long len)
3212 {
3213         struct checkdiff_t *data = priv;
3214         int marker_size = data->conflict_marker_size;
3215         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
3216         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
3217         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
3218         char *err;
3219         const char *line_prefix;
3220
3221         assert(data->o);
3222         line_prefix = diff_line_prefix(data->o);
3223
3224         if (line[0] == '+') {
3225                 unsigned bad;
3226                 data->lineno++;
3227                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
3228                         data->status |= 1;
3229                         fprintf(data->o->file,
3230                                 "%s%s:%d: leftover conflict marker\n",
3231                                 line_prefix, data->filename, data->lineno);
3232                 }
3233                 bad = ws_check(line + 1, len - 1, data->ws_rule);
3234                 if (!bad)
3235                         return;
3236                 data->status |= bad;
3237                 err = whitespace_error_string(bad);
3238                 fprintf(data->o->file, "%s%s:%d: %s.\n",
3239                         line_prefix, data->filename, data->lineno, err);
3240                 free(err);
3241                 emit_line(data->o, set, reset, line, 1);
3242                 ws_check_emit(line + 1, len - 1, data->ws_rule,
3243                               data->o->file, set, reset, ws);
3244         } else if (line[0] == ' ') {
3245                 data->lineno++;
3246         }
3247 }
3248
3249 static unsigned char *deflate_it(char *data,
3250                                  unsigned long size,
3251                                  unsigned long *result_size)
3252 {
3253         int bound;
3254         unsigned char *deflated;
3255         git_zstream stream;
3256
3257         git_deflate_init(&stream, zlib_compression_level);
3258         bound = git_deflate_bound(&stream, size);
3259         deflated = xmalloc(bound);
3260         stream.next_out = deflated;
3261         stream.avail_out = bound;
3262
3263         stream.next_in = (unsigned char *)data;
3264         stream.avail_in = size;
3265         while (git_deflate(&stream, Z_FINISH) == Z_OK)
3266                 ; /* nothing */
3267         git_deflate_end(&stream);
3268         *result_size = stream.total_out;
3269         return deflated;
3270 }
3271
3272 static void emit_binary_diff_body(struct diff_options *o,
3273                                   mmfile_t *one, mmfile_t *two)
3274 {
3275         void *cp;
3276         void *delta;
3277         void *deflated;
3278         void *data;
3279         unsigned long orig_size;
3280         unsigned long delta_size;
3281         unsigned long deflate_size;
3282         unsigned long data_size;
3283
3284         /* We could do deflated delta, or we could do just deflated two,
3285          * whichever is smaller.
3286          */
3287         delta = NULL;
3288         deflated = deflate_it(two->ptr, two->size, &deflate_size);
3289         if (one->size && two->size) {
3290                 delta = diff_delta(one->ptr, one->size,
3291                                    two->ptr, two->size,
3292                                    &delta_size, deflate_size);
3293                 if (delta) {
3294                         void *to_free = delta;
3295                         orig_size = delta_size;
3296                         delta = deflate_it(delta, delta_size, &delta_size);
3297                         free(to_free);
3298                 }
3299         }
3300
3301         if (delta && delta_size < deflate_size) {
3302                 char *s = xstrfmt("%"PRIuMAX , (uintmax_t)orig_size);
3303                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
3304                                  s, strlen(s), 0);
3305                 free(s);
3306                 free(deflated);
3307                 data = delta;
3308                 data_size = delta_size;
3309         } else {
3310                 char *s = xstrfmt("%lu", two->size);
3311                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
3312                                  s, strlen(s), 0);
3313                 free(s);
3314                 free(delta);
3315                 data = deflated;
3316                 data_size = deflate_size;
3317         }
3318
3319         /* emit data encoded in base85 */
3320         cp = data;
3321         while (data_size) {
3322                 int len;
3323                 int bytes = (52 < data_size) ? 52 : data_size;
3324                 char line[71];
3325                 data_size -= bytes;
3326                 if (bytes <= 26)
3327                         line[0] = bytes + 'A' - 1;
3328                 else
3329                         line[0] = bytes - 26 + 'a' - 1;
3330                 encode_85(line + 1, cp, bytes);
3331                 cp = (char *) cp + bytes;
3332
3333                 len = strlen(line);
3334                 line[len++] = '\n';
3335                 line[len] = '\0';
3336
3337                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
3338                                  line, len, 0);
3339         }
3340         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
3341         free(data);
3342 }
3343
3344 static void emit_binary_diff(struct diff_options *o,
3345                              mmfile_t *one, mmfile_t *two)
3346 {
3347         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
3348         emit_binary_diff_body(o, one, two);
3349         emit_binary_diff_body(o, two, one);
3350 }
3351
3352 int diff_filespec_is_binary(struct repository *r,
3353                             struct diff_filespec *one)
3354 {
3355         if (one->is_binary == -1) {
3356                 diff_filespec_load_driver(one, r->index);
3357                 if (one->driver->binary != -1)
3358                         one->is_binary = one->driver->binary;
3359                 else {
3360                         if (!one->data && DIFF_FILE_VALID(one))
3361                                 diff_populate_filespec(r, one, CHECK_BINARY);
3362                         if (one->is_binary == -1 && one->data)
3363                                 one->is_binary = buffer_is_binary(one->data,
3364                                                 one->size);
3365                         if (one->is_binary == -1)
3366                                 one->is_binary = 0;
3367                 }
3368         }
3369         return one->is_binary;
3370 }
3371
3372 static const struct userdiff_funcname *
3373 diff_funcname_pattern(struct diff_options *o, struct diff_filespec *one)
3374 {
3375         diff_filespec_load_driver(one, o->repo->index);
3376         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3377 }
3378
3379 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3380 {
3381         if (!options->a_prefix)
3382                 options->a_prefix = a;
3383         if (!options->b_prefix)
3384                 options->b_prefix = b;
3385 }
3386
3387 struct userdiff_driver *get_textconv(struct repository *r,
3388                                      struct diff_filespec *one)
3389 {
3390         if (!DIFF_FILE_VALID(one))
3391                 return NULL;
3392
3393         diff_filespec_load_driver(one, r->index);
3394         return userdiff_get_textconv(r, one->driver);
3395 }
3396
3397 static void builtin_diff(const char *name_a,
3398                          const char *name_b,
3399                          struct diff_filespec *one,
3400                          struct diff_filespec *two,
3401                          const char *xfrm_msg,
3402                          int must_show_header,
3403                          struct diff_options *o,
3404                          int complete_rewrite)
3405 {
3406         mmfile_t mf1, mf2;
3407         const char *lbl[2];
3408         char *a_one, *b_two;
3409         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3410         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3411         const char *a_prefix, *b_prefix;
3412         struct userdiff_driver *textconv_one = NULL;
3413         struct userdiff_driver *textconv_two = NULL;
3414         struct strbuf header = STRBUF_INIT;
3415         const char *line_prefix = diff_line_prefix(o);
3416
3417         diff_set_mnemonic_prefix(o, "a/", "b/");
3418         if (o->flags.reverse_diff) {
3419                 a_prefix = o->b_prefix;
3420                 b_prefix = o->a_prefix;
3421         } else {
3422                 a_prefix = o->a_prefix;
3423                 b_prefix = o->b_prefix;
3424         }
3425
3426         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3427             (!one->mode || S_ISGITLINK(one->mode)) &&
3428             (!two->mode || S_ISGITLINK(two->mode))) {
3429                 show_submodule_summary(o, one->path ? one->path : two->path,
3430                                 &one->oid, &two->oid,
3431                                 two->dirty_submodule);
3432                 return;
3433         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3434                    (!one->mode || S_ISGITLINK(one->mode)) &&
3435                    (!two->mode || S_ISGITLINK(two->mode))) {
3436                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3437                                 &one->oid, &two->oid,
3438                                 two->dirty_submodule);
3439                 return;
3440         }
3441
3442         if (o->flags.allow_textconv) {
3443                 textconv_one = get_textconv(o->repo, one);
3444                 textconv_two = get_textconv(o->repo, two);
3445         }
3446
3447         /* Never use a non-valid filename anywhere if at all possible */
3448         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3449         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3450
3451         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3452         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3453         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3454         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3455         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3456         if (lbl[0][0] == '/') {
3457                 /* /dev/null */
3458                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3459                 if (xfrm_msg)
3460                         strbuf_addstr(&header, xfrm_msg);
3461                 must_show_header = 1;
3462         }
3463         else if (lbl[1][0] == '/') {
3464                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3465                 if (xfrm_msg)
3466                         strbuf_addstr(&header, xfrm_msg);
3467                 must_show_header = 1;
3468         }
3469         else {
3470                 if (one->mode != two->mode) {
3471                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3472                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3473                         must_show_header = 1;
3474                 }
3475                 if (xfrm_msg)
3476                         strbuf_addstr(&header, xfrm_msg);
3477
3478                 /*
3479                  * we do not run diff between different kind
3480                  * of objects.
3481                  */
3482                 if ((one->mode ^ two->mode) & S_IFMT)
3483                         goto free_ab_and_return;
3484                 if (complete_rewrite &&
3485                     (textconv_one || !diff_filespec_is_binary(o->repo, one)) &&
3486                     (textconv_two || !diff_filespec_is_binary(o->repo, two))) {
3487                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3488                                          header.buf, header.len, 0);
3489                         strbuf_reset(&header);
3490                         emit_rewrite_diff(name_a, name_b, one, two,
3491                                           textconv_one, textconv_two, o);
3492                         o->found_changes = 1;
3493                         goto free_ab_and_return;
3494                 }
3495         }
3496
3497         if (o->irreversible_delete && lbl[1][0] == '/') {
3498                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3499                                  header.len, 0);
3500                 strbuf_reset(&header);
3501                 goto free_ab_and_return;
3502         } else if (!o->flags.text &&
3503                    ( (!textconv_one && diff_filespec_is_binary(o->repo, one)) ||
3504                      (!textconv_two && diff_filespec_is_binary(o->repo, two)) )) {
3505                 struct strbuf sb = STRBUF_INIT;
3506                 if (!one->data && !two->data &&
3507                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3508                     !o->flags.binary) {
3509                         if (oideq(&one->oid, &two->oid)) {
3510                                 if (must_show_header)
3511                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3512                                                          header.buf, header.len,
3513                                                          0);
3514                                 goto free_ab_and_return;
3515                         }
3516                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3517                                          header.buf, header.len, 0);
3518                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3519                                     diff_line_prefix(o), lbl[0], lbl[1]);
3520                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3521                                          sb.buf, sb.len, 0);
3522                         strbuf_release(&sb);
3523                         goto free_ab_and_return;
3524                 }
3525                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3526                     fill_mmfile(o->repo, &mf2, two) < 0)
3527                         die("unable to read files to diff");
3528                 /* Quite common confusing case */
3529                 if (mf1.size == mf2.size &&
3530                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3531                         if (must_show_header)
3532                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3533                                                  header.buf, header.len, 0);
3534                         goto free_ab_and_return;
3535                 }
3536                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3537                 strbuf_reset(&header);
3538                 if (o->flags.binary)
3539                         emit_binary_diff(o, &mf1, &mf2);
3540                 else {
3541                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3542                                     diff_line_prefix(o), lbl[0], lbl[1]);
3543                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3544                                          sb.buf, sb.len, 0);
3545                         strbuf_release(&sb);
3546                 }
3547                 o->found_changes = 1;
3548         } else {
3549                 /* Crazy xdl interfaces.. */
3550                 const char *diffopts;
3551                 const char *v;
3552                 xpparam_t xpp;
3553                 xdemitconf_t xecfg;
3554                 struct emit_callback ecbdata;
3555                 const struct userdiff_funcname *pe;
3556
3557                 if (must_show_header) {
3558                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3559                                          header.buf, header.len, 0);
3560                         strbuf_reset(&header);
3561                 }
3562
3563                 mf1.size = fill_textconv(o->repo, textconv_one, one, &mf1.ptr);
3564                 mf2.size = fill_textconv(o->repo, textconv_two, two, &mf2.ptr);
3565
3566                 pe = diff_funcname_pattern(o, one);
3567                 if (!pe)
3568                         pe = diff_funcname_pattern(o, two);
3569
3570                 memset(&xpp, 0, sizeof(xpp));
3571                 memset(&xecfg, 0, sizeof(xecfg));
3572                 memset(&ecbdata, 0, sizeof(ecbdata));
3573                 if (o->flags.suppress_diff_headers)
3574                         lbl[0] = NULL;
3575                 ecbdata.label_path = lbl;
3576                 ecbdata.color_diff = want_color(o->use_color);
3577                 ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
3578                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3579                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3580                 ecbdata.opt = o;
3581                 if (header.len && !o->flags.suppress_diff_headers)
3582                         ecbdata.header = &header;
3583                 xpp.flags = o->xdl_opts;
3584                 xpp.anchors = o->anchors;
3585                 xpp.anchors_nr = o->anchors_nr;
3586                 xecfg.ctxlen = o->context;
3587                 xecfg.interhunkctxlen = o->interhunkcontext;
3588                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3589                 if (o->flags.funccontext)
3590                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3591                 if (pe)
3592                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3593
3594                 diffopts = getenv("GIT_DIFF_OPTS");
3595                 if (!diffopts)
3596                         ;
3597                 else if (skip_prefix(diffopts, "--unified=", &v))
3598                         xecfg.ctxlen = strtoul(v, NULL, 10);
3599                 else if (skip_prefix(diffopts, "-u", &v))
3600                         xecfg.ctxlen = strtoul(v, NULL, 10);
3601
3602                 if (o->word_diff)
3603                         init_diff_words_data(&ecbdata, o, one, two);
3604                 if (xdi_diff_outf(&mf1, &mf2, NULL, fn_out_consume,
3605                                   &ecbdata, &xpp, &xecfg))
3606                         die("unable to generate diff for %s", one->path);
3607                 if (o->word_diff)
3608                         free_diff_words_data(&ecbdata);
3609                 if (textconv_one)
3610                         free(mf1.ptr);
3611                 if (textconv_two)
3612                         free(mf2.ptr);
3613                 xdiff_clear_find_func(&xecfg);
3614         }
3615
3616  free_ab_and_return:
3617         strbuf_release(&header);
3618         diff_free_filespec_data(one);
3619         diff_free_filespec_data(two);
3620         free(a_one);
3621         free(b_two);
3622         return;
3623 }
3624
3625 static char *get_compact_summary(const struct diff_filepair *p, int is_renamed)
3626 {
3627         if (!is_renamed) {
3628                 if (p->status == DIFF_STATUS_ADDED) {
3629                         if (S_ISLNK(p->two->mode))
3630                                 return "new +l";
3631                         else if ((p->two->mode & 0777) == 0755)
3632                                 return "new +x";
3633                         else
3634                                 return "new";
3635                 } else if (p->status == DIFF_STATUS_DELETED)
3636                         return "gone";
3637         }
3638         if (S_ISLNK(p->one->mode) && !S_ISLNK(p->two->mode))
3639                 return "mode -l";
3640         else if (!S_ISLNK(p->one->mode) && S_ISLNK(p->two->mode))
3641                 return "mode +l";
3642         else if ((p->one->mode & 0777) == 0644 &&
3643                  (p->two->mode & 0777) == 0755)
3644                 return "mode +x";
3645         else if ((p->one->mode & 0777) == 0755 &&
3646                  (p->two->mode & 0777) == 0644)
3647                 return "mode -x";
3648         return NULL;
3649 }
3650
3651 static void builtin_diffstat(const char *name_a, const char *name_b,
3652                              struct diff_filespec *one,
3653                              struct diff_filespec *two,
3654                              struct diffstat_t *diffstat,
3655                              struct diff_options *o,
3656                              struct diff_filepair *p)
3657 {
3658         mmfile_t mf1, mf2;
3659         struct diffstat_file *data;
3660         int same_contents;
3661         int complete_rewrite = 0;
3662
3663         if (!DIFF_PAIR_UNMERGED(p)) {
3664                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3665                         complete_rewrite = 1;
3666         }
3667
3668         data = diffstat_add(diffstat, name_a, name_b);
3669         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3670         if (o->flags.stat_with_summary)
3671                 data->comments = get_compact_summary(p, data->is_renamed);
3672
3673         if (!one || !two) {
3674                 data->is_unmerged = 1;
3675                 return;
3676         }
3677
3678         same_contents = oideq(&one->oid, &two->oid);
3679
3680         if (diff_filespec_is_binary(o->repo, one) ||
3681             diff_filespec_is_binary(o->repo, two)) {
3682                 data->is_binary = 1;
3683                 if (same_contents) {
3684                         data->added = 0;
3685                         data->deleted = 0;
3686                 } else {
3687                         data->added = diff_filespec_size(o->repo, two);
3688                         data->deleted = diff_filespec_size(o->repo, one);
3689                 }
3690         }
3691
3692         else if (complete_rewrite) {
3693                 diff_populate_filespec(o->repo, one, 0);
3694                 diff_populate_filespec(o->repo, two, 0);
3695                 data->deleted = count_lines(one->data, one->size);
3696                 data->added = count_lines(two->data, two->size);
3697         }
3698
3699         else if (!same_contents) {
3700                 /* Crazy xdl interfaces.. */
3701                 xpparam_t xpp;
3702                 xdemitconf_t xecfg;
3703
3704                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3705                     fill_mmfile(o->repo, &mf2, two) < 0)
3706                         die("unable to read files to diff");
3707
3708                 memset(&xpp, 0, sizeof(xpp));
3709                 memset(&xecfg, 0, sizeof(xecfg));
3710                 xpp.flags = o->xdl_opts;
3711                 xpp.anchors = o->anchors;
3712                 xpp.anchors_nr = o->anchors_nr;
3713                 xecfg.ctxlen = o->context;
3714                 xecfg.interhunkctxlen = o->interhunkcontext;
3715                 if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
3716                                   diffstat_consume, diffstat, &xpp, &xecfg))
3717                         die("unable to generate diffstat for %s", one->path);
3718         }
3719
3720         diff_free_filespec_data(one);
3721         diff_free_filespec_data(two);
3722 }
3723
3724 static void builtin_checkdiff(const char *name_a, const char *name_b,
3725                               const char *attr_path,
3726                               struct diff_filespec *one,
3727                               struct diff_filespec *two,
3728                               struct diff_options *o)
3729 {
3730         mmfile_t mf1, mf2;
3731         struct checkdiff_t data;
3732
3733         if (!two)
3734                 return;
3735
3736         memset(&data, 0, sizeof(data));
3737         data.filename = name_b ? name_b : name_a;
3738         data.lineno = 0;
3739         data.o = o;
3740         data.ws_rule = whitespace_rule(o->repo->index, attr_path);
3741         data.conflict_marker_size = ll_merge_marker_size(o->repo->index, attr_path);
3742
3743         if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3744             fill_mmfile(o->repo, &mf2, two) < 0)
3745                 die("unable to read files to diff");
3746
3747         /*
3748          * All the other codepaths check both sides, but not checking
3749          * the "old" side here is deliberate.  We are checking the newly
3750          * introduced changes, and as long as the "new" side is text, we
3751          * can and should check what it introduces.
3752          */
3753         if (diff_filespec_is_binary(o->repo, two))
3754                 goto free_and_return;
3755         else {
3756                 /* Crazy xdl interfaces.. */
3757                 xpparam_t xpp;
3758                 xdemitconf_t xecfg;
3759
3760                 memset(&xpp, 0, sizeof(xpp));
3761                 memset(&xecfg, 0, sizeof(xecfg));
3762                 xecfg.ctxlen = 1; /* at least one context line */
3763                 xpp.flags = 0;
3764                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume_hunk,
3765                                   checkdiff_consume, &data,
3766                                   &xpp, &xecfg))
3767                         die("unable to generate checkdiff for %s", one->path);
3768
3769                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3770                         struct emit_callback ecbdata;
3771                         int blank_at_eof;
3772
3773                         ecbdata.ws_rule = data.ws_rule;
3774                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3775                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3776
3777                         if (blank_at_eof) {
3778                                 static char *err;
3779                                 if (!err)
3780                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3781                                 fprintf(o->file, "%s:%d: %s.\n",
3782                                         data.filename, blank_at_eof, err);
3783                                 data.status = 1; /* report errors */
3784                         }
3785                 }
3786         }
3787  free_and_return:
3788         diff_free_filespec_data(one);
3789         diff_free_filespec_data(two);
3790         if (data.status)
3791                 o->flags.check_failed = 1;
3792 }
3793
3794 struct diff_filespec *alloc_filespec(const char *path)
3795 {
3796         struct diff_filespec *spec;
3797
3798         FLEXPTR_ALLOC_STR(spec, path, path);
3799         spec->count = 1;
3800         spec->is_binary = -1;
3801         return spec;
3802 }
3803
3804 void free_filespec(struct diff_filespec *spec)
3805 {
3806         if (!--spec->count) {
3807                 diff_free_filespec_data(spec);
3808                 free(spec);
3809         }
3810 }
3811
3812 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3813                    int oid_valid, unsigned short mode)
3814 {
3815         if (mode) {
3816                 spec->mode = canon_mode(mode);
3817                 oidcpy(&spec->oid, oid);
3818                 spec->oid_valid = oid_valid;
3819         }
3820 }
3821
3822 /*
3823  * Given a name and sha1 pair, if the index tells us the file in
3824  * the work tree has that object contents, return true, so that
3825  * prepare_temp_file() does not have to inflate and extract.
3826  */
3827 static int reuse_worktree_file(struct index_state *istate,
3828                                const char *name,
3829                                const struct object_id *oid,
3830                                int want_file)
3831 {
3832         const struct cache_entry *ce;
3833         struct stat st;
3834         int pos, len;
3835
3836         /*
3837          * We do not read the cache ourselves here, because the
3838          * benchmark with my previous version that always reads cache
3839          * shows that it makes things worse for diff-tree comparing
3840          * two linux-2.6 kernel trees in an already checked out work
3841          * tree.  This is because most diff-tree comparisons deal with
3842          * only a small number of files, while reading the cache is
3843          * expensive for a large project, and its cost outweighs the
3844          * savings we get by not inflating the object to a temporary
3845          * file.  Practically, this code only helps when we are used
3846          * by diff-cache --cached, which does read the cache before
3847          * calling us.
3848          */
3849         if (!istate->cache)
3850                 return 0;
3851
3852         /* We want to avoid the working directory if our caller
3853          * doesn't need the data in a normal file, this system
3854          * is rather slow with its stat/open/mmap/close syscalls,
3855          * and the object is contained in a pack file.  The pack
3856          * is probably already open and will be faster to obtain
3857          * the data through than the working directory.  Loose
3858          * objects however would tend to be slower as they need
3859          * to be individually opened and inflated.
3860          */
3861         if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
3862                 return 0;
3863
3864         /*
3865          * Similarly, if we'd have to convert the file contents anyway, that
3866          * makes the optimization not worthwhile.
3867          */
3868         if (!want_file && would_convert_to_git(istate, name))
3869                 return 0;
3870
3871         len = strlen(name);
3872         pos = index_name_pos(istate, name, len);
3873         if (pos < 0)
3874                 return 0;
3875         ce = istate->cache[pos];
3876
3877         /*
3878          * This is not the sha1 we are looking for, or
3879          * unreusable because it is not a regular file.
3880          */
3881         if (!oideq(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3882                 return 0;
3883
3884         /*
3885          * If ce is marked as "assume unchanged", there is no
3886          * guarantee that work tree matches what we are looking for.
3887          */
3888         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3889                 return 0;
3890
3891         /*
3892          * If ce matches the file in the work tree, we can reuse it.
3893          */
3894         if (ce_uptodate(ce) ||
3895             (!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0)))
3896                 return 1;
3897
3898         return 0;
3899 }
3900
3901 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3902 {
3903         struct strbuf buf = STRBUF_INIT;
3904         char *dirty = "";
3905
3906         /* Are we looking at the work tree? */
3907         if (s->dirty_submodule)
3908                 dirty = "-dirty";
3909
3910         strbuf_addf(&buf, "Subproject commit %s%s\n",
3911                     oid_to_hex(&s->oid), dirty);
3912         s->size = buf.len;
3913         if (size_only) {
3914                 s->data = NULL;
3915                 strbuf_release(&buf);
3916         } else {
3917                 s->data = strbuf_detach(&buf, NULL);
3918                 s->should_free = 1;
3919         }
3920         return 0;
3921 }
3922
3923 /*
3924  * While doing rename detection and pickaxe operation, we may need to
3925  * grab the data for the blob (or file) for our own in-core comparison.
3926  * diff_filespec has data and size fields for this purpose.
3927  */
3928 int diff_populate_filespec(struct repository *r,
3929                            struct diff_filespec *s,
3930                            unsigned int flags)
3931 {
3932         int size_only = flags & CHECK_SIZE_ONLY;
3933         int err = 0;
3934         int conv_flags = global_conv_flags_eol;
3935         /*
3936          * demote FAIL to WARN to allow inspecting the situation
3937          * instead of refusing.
3938          */
3939         if (conv_flags & CONV_EOL_RNDTRP_DIE)
3940                 conv_flags = CONV_EOL_RNDTRP_WARN;
3941
3942         if (!DIFF_FILE_VALID(s))
3943                 die("internal error: asking to populate invalid file.");
3944         if (S_ISDIR(s->mode))
3945                 return -1;
3946
3947         if (s->data)
3948                 return 0;
3949
3950         if (size_only && 0 < s->size)
3951                 return 0;
3952
3953         if (S_ISGITLINK(s->mode))
3954                 return diff_populate_gitlink(s, size_only);
3955
3956         if (!s->oid_valid ||
3957             reuse_worktree_file(r->index, s->path, &s->oid, 0)) {
3958                 struct strbuf buf = STRBUF_INIT;
3959                 struct stat st;
3960                 int fd;
3961
3962                 if (lstat(s->path, &st) < 0) {
3963                 err_empty:
3964                         err = -1;
3965                 empty:
3966                         s->data = (char *)"";
3967                         s->size = 0;
3968                         return err;
3969                 }
3970                 s->size = xsize_t(st.st_size);
3971                 if (!s->size)
3972                         goto empty;
3973                 if (S_ISLNK(st.st_mode)) {
3974                         struct strbuf sb = STRBUF_INIT;
3975
3976                         if (strbuf_readlink(&sb, s->path, s->size))
3977                                 goto err_empty;
3978                         s->size = sb.len;
3979                         s->data = strbuf_detach(&sb, NULL);
3980                         s->should_free = 1;
3981                         return 0;
3982                 }
3983
3984                 /*
3985                  * Even if the caller would be happy with getting
3986                  * only the size, we cannot return early at this
3987                  * point if the path requires us to run the content
3988                  * conversion.
3989                  */
3990                 if (size_only && !would_convert_to_git(r->index, s->path))
3991                         return 0;
3992
3993                 /*
3994                  * Note: this check uses xsize_t(st.st_size) that may
3995                  * not be the true size of the blob after it goes
3996                  * through convert_to_git().  This may not strictly be
3997                  * correct, but the whole point of big_file_threshold
3998                  * and is_binary check being that we want to avoid
3999                  * opening the file and inspecting the contents, this
4000                  * is probably fine.
4001                  */
4002                 if ((flags & CHECK_BINARY) &&
4003                     s->size > big_file_threshold && s->is_binary == -1) {
4004                         s->is_binary = 1;
4005                         return 0;
4006                 }
4007                 fd = open(s->path, O_RDONLY);
4008                 if (fd < 0)
4009                         goto err_empty;
4010                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
4011                 close(fd);
4012                 s->should_munmap = 1;
4013
4014                 /*
4015                  * Convert from working tree format to canonical git format
4016                  */
4017                 if (convert_to_git(r->index, s->path, s->data, s->size, &buf, conv_flags)) {
4018                         size_t size = 0;
4019                         munmap(s->data, s->size);
4020                         s->should_munmap = 0;
4021                         s->data = strbuf_detach(&buf, &size);
4022                         s->size = size;
4023                         s->should_free = 1;
4024                 }
4025         }
4026         else {
4027                 enum object_type type;
4028                 if (size_only || (flags & CHECK_BINARY)) {
4029                         type = oid_object_info(r, &s->oid, &s->size);
4030                         if (type < 0)
4031                                 die("unable to read %s",
4032                                     oid_to_hex(&s->oid));
4033                         if (size_only)
4034                                 return 0;
4035                         if (s->size > big_file_threshold && s->is_binary == -1) {
4036                                 s->is_binary = 1;
4037                                 return 0;
4038                         }
4039                 }
4040                 s->data = read_object_file(&s->oid, &type, &s->size);
4041                 if (!s->data)
4042                         die("unable to read %s", oid_to_hex(&s->oid));
4043                 s->should_free = 1;
4044         }
4045         return 0;
4046 }
4047
4048 void diff_free_filespec_blob(struct diff_filespec *s)
4049 {
4050         if (s->should_free)
4051                 free(s->data);
4052         else if (s->should_munmap)
4053                 munmap(s->data, s->size);
4054
4055         if (s->should_free || s->should_munmap) {
4056                 s->should_free = s->should_munmap = 0;
4057                 s->data = NULL;
4058         }
4059 }
4060
4061 void diff_free_filespec_data(struct diff_filespec *s)
4062 {
4063         diff_free_filespec_blob(s);
4064         FREE_AND_NULL(s->cnt_data);
4065 }
4066
4067 static void prep_temp_blob(struct index_state *istate,
4068                            const char *path, struct diff_tempfile *temp,
4069                            void *blob,
4070                            unsigned long size,
4071                            const struct object_id *oid,
4072                            int mode)
4073 {
4074         struct strbuf buf = STRBUF_INIT;
4075         struct strbuf tempfile = STRBUF_INIT;
4076         char *path_dup = xstrdup(path);
4077         const char *base = basename(path_dup);
4078
4079         /* Generate "XXXXXX_basename.ext" */
4080         strbuf_addstr(&tempfile, "XXXXXX_");
4081         strbuf_addstr(&tempfile, base);
4082
4083         temp->tempfile = mks_tempfile_ts(tempfile.buf, strlen(base) + 1);
4084         if (!temp->tempfile)
4085                 die_errno("unable to create temp-file");
4086         if (convert_to_working_tree(istate, path,
4087                         (const char *)blob, (size_t)size, &buf)) {
4088                 blob = buf.buf;
4089                 size = buf.len;
4090         }
4091         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
4092             close_tempfile_gently(temp->tempfile))
4093                 die_errno("unable to write temp-file");
4094         temp->name = get_tempfile_path(temp->tempfile);
4095         oid_to_hex_r(temp->hex, oid);
4096         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
4097         strbuf_release(&buf);
4098         strbuf_release(&tempfile);
4099         free(path_dup);
4100 }
4101
4102 static struct diff_tempfile *prepare_temp_file(struct repository *r,
4103                                                const char *name,
4104                                                struct diff_filespec *one)
4105 {
4106         struct diff_tempfile *temp = claim_diff_tempfile();
4107
4108         if (!DIFF_FILE_VALID(one)) {
4109         not_a_valid_file:
4110                 /* A '-' entry produces this for file-2, and
4111                  * a '+' entry produces this for file-1.
4112                  */
4113                 temp->name = "/dev/null";
4114                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
4115                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
4116                 return temp;
4117         }
4118
4119         if (!S_ISGITLINK(one->mode) &&
4120             (!one->oid_valid ||
4121              reuse_worktree_file(r->index, name, &one->oid, 1))) {
4122                 struct stat st;
4123                 if (lstat(name, &st) < 0) {
4124                         if (errno == ENOENT)
4125                                 goto not_a_valid_file;
4126                         die_errno("stat(%s)", name);
4127                 }
4128                 if (S_ISLNK(st.st_mode)) {
4129                         struct strbuf sb = STRBUF_INIT;
4130                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
4131                                 die_errno("readlink(%s)", name);
4132                         prep_temp_blob(r->index, name, temp, sb.buf, sb.len,
4133                                        (one->oid_valid ?
4134                                         &one->oid : &null_oid),
4135                                        (one->oid_valid ?
4136                                         one->mode : S_IFLNK));
4137                         strbuf_release(&sb);
4138                 }
4139                 else {
4140                         /* we can borrow from the file in the work tree */
4141                         temp->name = name;
4142                         if (!one->oid_valid)
4143                                 oid_to_hex_r(temp->hex, &null_oid);
4144                         else
4145                                 oid_to_hex_r(temp->hex, &one->oid);
4146                         /* Even though we may sometimes borrow the
4147                          * contents from the work tree, we always want
4148                          * one->mode.  mode is trustworthy even when
4149                          * !(one->oid_valid), as long as
4150                          * DIFF_FILE_VALID(one).
4151                          */
4152                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
4153                 }
4154                 return temp;
4155         }
4156         else {
4157                 if (diff_populate_filespec(r, one, 0))
4158                         die("cannot read data blob for %s", one->path);
4159                 prep_temp_blob(r->index, name, temp,
4160                                one->data, one->size,
4161                                &one->oid, one->mode);
4162         }
4163         return temp;
4164 }
4165
4166 static void add_external_diff_name(struct repository *r,
4167                                    struct argv_array *argv,
4168                                    const char *name,
4169                                    struct diff_filespec *df)
4170 {
4171         struct diff_tempfile *temp = prepare_temp_file(r, name, df);
4172         argv_array_push(argv, temp->name);
4173         argv_array_push(argv, temp->hex);
4174         argv_array_push(argv, temp->mode);
4175 }
4176
4177 /* An external diff command takes:
4178  *
4179  * diff-cmd name infile1 infile1-sha1 infile1-mode \
4180  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
4181  *
4182  */
4183 static void run_external_diff(const char *pgm,
4184                               const char *name,
4185                               const char *other,
4186                               struct diff_filespec *one,
4187                               struct diff_filespec *two,
4188                               const char *xfrm_msg,
4189                               struct diff_options *o)
4190 {
4191         struct argv_array argv = ARGV_ARRAY_INIT;
4192         struct argv_array env = ARGV_ARRAY_INIT;
4193         struct diff_queue_struct *q = &diff_queued_diff;
4194
4195         argv_array_push(&argv, pgm);
4196         argv_array_push(&argv, name);
4197
4198         if (one && two) {
4199                 add_external_diff_name(o->repo, &argv, name, one);
4200                 if (!other)
4201                         add_external_diff_name(o->repo, &argv, name, two);
4202                 else {
4203                         add_external_diff_name(o->repo, &argv, other, two);
4204                         argv_array_push(&argv, other);
4205                         argv_array_push(&argv, xfrm_msg);
4206                 }
4207         }
4208
4209         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
4210         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
4211
4212         diff_free_filespec_data(one);
4213         diff_free_filespec_data(two);
4214         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
4215                 die(_("external diff died, stopping at %s"), name);
4216
4217         remove_tempfile();
4218         argv_array_clear(&argv);
4219         argv_array_clear(&env);
4220 }
4221
4222 static int similarity_index(struct diff_filepair *p)
4223 {
4224         return p->score * 100 / MAX_SCORE;
4225 }
4226
4227 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
4228 {
4229         if (startup_info->have_repository)
4230                 return find_unique_abbrev(oid, abbrev);
4231         else {
4232                 char *hex = oid_to_hex(oid);
4233                 if (abbrev < 0)
4234                         abbrev = FALLBACK_DEFAULT_ABBREV;
4235                 if (abbrev > the_hash_algo->hexsz)
4236                         BUG("oid abbreviation out of range: %d", abbrev);
4237                 if (abbrev)
4238                         hex[abbrev] = '\0';
4239                 return hex;
4240         }
4241 }
4242
4243 static void fill_metainfo(struct strbuf *msg,
4244                           const char *name,
4245                           const char *other,
4246                           struct diff_filespec *one,
4247                           struct diff_filespec *two,
4248                           struct diff_options *o,
4249                           struct diff_filepair *p,
4250                           int *must_show_header,
4251                           int use_color)
4252 {
4253         const char *set = diff_get_color(use_color, DIFF_METAINFO);
4254         const char *reset = diff_get_color(use_color, DIFF_RESET);
4255         const char *line_prefix = diff_line_prefix(o);
4256
4257         *must_show_header = 1;
4258         strbuf_init(msg, PATH_MAX * 2 + 300);
4259         switch (p->status) {
4260         case DIFF_STATUS_COPIED:
4261                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4262                             line_prefix, set, similarity_index(p));
4263                 strbuf_addf(msg, "%s\n%s%scopy from ",
4264                             reset,  line_prefix, set);
4265                 quote_c_style(name, msg, NULL, 0);
4266                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
4267                 quote_c_style(other, msg, NULL, 0);
4268                 strbuf_addf(msg, "%s\n", reset);
4269                 break;
4270         case DIFF_STATUS_RENAMED:
4271                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4272                             line_prefix, set, similarity_index(p));
4273                 strbuf_addf(msg, "%s\n%s%srename from ",
4274                             reset, line_prefix, set);
4275                 quote_c_style(name, msg, NULL, 0);
4276                 strbuf_addf(msg, "%s\n%s%srename to ",
4277                             reset, line_prefix, set);
4278                 quote_c_style(other, msg, NULL, 0);
4279                 strbuf_addf(msg, "%s\n", reset);
4280                 break;
4281         case DIFF_STATUS_MODIFIED:
4282                 if (p->score) {
4283                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
4284                                     line_prefix,
4285                                     set, similarity_index(p), reset);
4286                         break;
4287                 }
4288                 /* fallthru */
4289         default:
4290                 *must_show_header = 0;
4291         }
4292         if (one && two && !oideq(&one->oid, &two->oid)) {
4293                 const unsigned hexsz = the_hash_algo->hexsz;
4294                 int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
4295
4296                 if (o->flags.binary) {
4297                         mmfile_t mf;
4298                         if ((!fill_mmfile(o->repo, &mf, one) &&
4299                              diff_filespec_is_binary(o->repo, one)) ||
4300                             (!fill_mmfile(o->repo, &mf, two) &&
4301                              diff_filespec_is_binary(o->repo, two)))
4302                                 abbrev = hexsz;
4303                 }
4304                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
4305                             diff_abbrev_oid(&one->oid, abbrev),
4306                             diff_abbrev_oid(&two->oid, abbrev));
4307                 if (one->mode == two->mode)
4308                         strbuf_addf(msg, " %06o", one->mode);
4309                 strbuf_addf(msg, "%s\n", reset);
4310         }
4311 }
4312
4313 static void run_diff_cmd(const char *pgm,
4314                          const char *name,
4315                          const char *other,
4316                          const char *attr_path,
4317                          struct diff_filespec *one,
4318                          struct diff_filespec *two,
4319                          struct strbuf *msg,
4320                          struct diff_options *o,
4321                          struct diff_filepair *p)
4322 {
4323         const char *xfrm_msg = NULL;
4324         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
4325         int must_show_header = 0;
4326
4327
4328         if (o->flags.allow_external) {
4329                 struct userdiff_driver *drv;
4330
4331                 drv = userdiff_find_by_path(o->repo->index, attr_path);
4332                 if (drv && drv->external)
4333                         pgm = drv->external;
4334         }
4335
4336         if (msg) {
4337                 /*
4338                  * don't use colors when the header is intended for an
4339                  * external diff driver
4340                  */
4341                 fill_metainfo(msg, name, other, one, two, o, p,
4342                               &must_show_header,
4343                               want_color(o->use_color) && !pgm);
4344                 xfrm_msg = msg->len ? msg->buf : NULL;
4345         }
4346
4347         if (pgm) {
4348                 run_external_diff(pgm, name, other, one, two, xfrm_msg, o);
4349                 return;
4350         }
4351         if (one && two)
4352                 builtin_diff(name, other ? other : name,
4353                              one, two, xfrm_msg, must_show_header,
4354                              o, complete_rewrite);
4355         else
4356                 fprintf(o->file, "* Unmerged path %s\n", name);
4357 }
4358
4359 static void diff_fill_oid_info(struct diff_filespec *one, struct index_state *istate)
4360 {
4361         if (DIFF_FILE_VALID(one)) {
4362                 if (!one->oid_valid) {
4363                         struct stat st;
4364                         if (one->is_stdin) {
4365                                 oidclr(&one->oid);
4366                                 return;
4367                         }
4368                         if (lstat(one->path, &st) < 0)
4369                                 die_errno("stat '%s'", one->path);
4370                         if (index_path(istate, &one->oid, one->path, &st, 0))
4371                                 die("cannot hash %s", one->path);
4372                 }
4373         }
4374         else
4375                 oidclr(&one->oid);
4376 }
4377
4378 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
4379 {
4380         /* Strip the prefix but do not molest /dev/null and absolute paths */
4381         if (*namep && !is_absolute_path(*namep)) {
4382                 *namep += prefix_length;
4383                 if (**namep == '/')
4384                         ++*namep;
4385         }
4386         if (*otherp && !is_absolute_path(*otherp)) {
4387                 *otherp += prefix_length;
4388                 if (**otherp == '/')
4389                         ++*otherp;
4390         }
4391 }
4392
4393 static void run_diff(struct diff_filepair *p, struct diff_options *o)
4394 {
4395         const char *pgm = external_diff();
4396         struct strbuf msg;
4397         struct diff_filespec *one = p->one;
4398         struct diff_filespec *two = p->two;
4399         const char *name;
4400         const char *other;
4401         const char *attr_path;
4402
4403         name  = one->path;
4404         other = (strcmp(name, two->path) ? two->path : NULL);
4405         attr_path = name;
4406         if (o->prefix_length)
4407                 strip_prefix(o->prefix_length, &name, &other);
4408
4409         if (!o->flags.allow_external)
4410                 pgm = NULL;
4411
4412         if (DIFF_PAIR_UNMERGED(p)) {
4413                 run_diff_cmd(pgm, name, NULL, attr_path,
4414                              NULL, NULL, NULL, o, p);
4415                 return;
4416         }
4417
4418         diff_fill_oid_info(one, o->repo->index);
4419         diff_fill_oid_info(two, o->repo->index);
4420
4421         if (!pgm &&
4422             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4423             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4424                 /*
4425                  * a filepair that changes between file and symlink
4426                  * needs to be split into deletion and creation.
4427                  */
4428                 struct diff_filespec *null = alloc_filespec(two->path);
4429                 run_diff_cmd(NULL, name, other, attr_path,
4430                              one, null, &msg,
4431                              o, p);
4432                 free(null);
4433                 strbuf_release(&msg);
4434
4435                 null = alloc_filespec(one->path);
4436                 run_diff_cmd(NULL, name, other, attr_path,
4437                              null, two, &msg, o, p);
4438                 free(null);
4439         }
4440         else
4441                 run_diff_cmd(pgm, name, other, attr_path,
4442                              one, two, &msg, o, p);
4443
4444         strbuf_release(&msg);
4445 }
4446
4447 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4448                          struct diffstat_t *diffstat)
4449 {
4450         const char *name;
4451         const char *other;
4452
4453         if (DIFF_PAIR_UNMERGED(p)) {
4454                 /* unmerged */
4455                 builtin_diffstat(p->one->path, NULL, NULL, NULL,
4456                                  diffstat, o, p);
4457                 return;
4458         }
4459
4460         name = p->one->path;
4461         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4462
4463         if (o->prefix_length)
4464                 strip_prefix(o->prefix_length, &name, &other);
4465
4466         diff_fill_oid_info(p->one, o->repo->index);
4467         diff_fill_oid_info(p->two, o->repo->index);
4468
4469         builtin_diffstat(name, other, p->one, p->two,
4470                          diffstat, o, p);
4471 }
4472
4473 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4474 {
4475         const char *name;
4476         const char *other;
4477         const char *attr_path;
4478
4479         if (DIFF_PAIR_UNMERGED(p)) {
4480                 /* unmerged */
4481                 return;
4482         }
4483
4484         name = p->one->path;
4485         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4486         attr_path = other ? other : name;
4487
4488         if (o->prefix_length)
4489                 strip_prefix(o->prefix_length, &name, &other);
4490
4491         diff_fill_oid_info(p->one, o->repo->index);
4492         diff_fill_oid_info(p->two, o->repo->index);
4493
4494         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4495 }
4496
4497 static void prep_parse_options(struct diff_options *options);
4498
4499 void repo_diff_setup(struct repository *r, struct diff_options *options)
4500 {
4501         memcpy(options, &default_diff_options, sizeof(*options));
4502
4503         options->file = stdout;
4504         options->repo = r;
4505
4506         options->output_indicators[OUTPUT_INDICATOR_NEW] = '+';
4507         options->output_indicators[OUTPUT_INDICATOR_OLD] = '-';
4508         options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = ' ';
4509         options->abbrev = DEFAULT_ABBREV;
4510         options->line_termination = '\n';
4511         options->break_opt = -1;
4512         options->rename_limit = -1;
4513         options->dirstat_permille = diff_dirstat_permille_default;
4514         options->context = diff_context_default;
4515         options->interhunkcontext = diff_interhunk_context_default;
4516         options->ws_error_highlight = ws_error_highlight_default;
4517         options->flags.rename_empty = 1;
4518         options->objfind = NULL;
4519
4520         /* pathchange left =NULL by default */
4521         options->change = diff_change;
4522         options->add_remove = diff_addremove;
4523         options->use_color = diff_use_color_default;
4524         options->detect_rename = diff_detect_rename_default;
4525         options->xdl_opts |= diff_algorithm;
4526         if (diff_indent_heuristic)
4527                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4528
4529         options->orderfile = diff_order_file_cfg;
4530
4531         if (diff_no_prefix) {
4532                 options->a_prefix = options->b_prefix = "";
4533         } else if (!diff_mnemonic_prefix) {
4534                 options->a_prefix = "a/";
4535                 options->b_prefix = "b/";
4536         }
4537
4538         options->color_moved = diff_color_moved_default;
4539         options->color_moved_ws_handling = diff_color_moved_ws_default;
4540
4541         prep_parse_options(options);
4542 }
4543
4544 void diff_setup_done(struct diff_options *options)
4545 {
4546         unsigned check_mask = DIFF_FORMAT_NAME |
4547                               DIFF_FORMAT_NAME_STATUS |
4548                               DIFF_FORMAT_CHECKDIFF |
4549                               DIFF_FORMAT_NO_OUTPUT;
4550         /*
4551          * This must be signed because we're comparing against a potentially
4552          * negative value.
4553          */
4554         const int hexsz = the_hash_algo->hexsz;
4555
4556         if (options->set_default)
4557                 options->set_default(options);
4558
4559         if (HAS_MULTI_BITS(options->output_format & check_mask))
4560                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4561
4562         if (HAS_MULTI_BITS(options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
4563                 die(_("-G, -S and --find-object are mutually exclusive"));
4564
4565         /*
4566          * Most of the time we can say "there are changes"
4567          * only by checking if there are changed paths, but
4568          * --ignore-whitespace* options force us to look
4569          * inside contents.
4570          */
4571
4572         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4573                 options->flags.diff_from_contents = 1;
4574         else
4575                 options->flags.diff_from_contents = 0;
4576
4577         if (options->flags.find_copies_harder)
4578                 options->detect_rename = DIFF_DETECT_COPY;
4579
4580         if (!options->flags.relative_name)
4581                 options->prefix = NULL;
4582         if (options->prefix)
4583                 options->prefix_length = strlen(options->prefix);
4584         else
4585                 options->prefix_length = 0;
4586
4587         if (options->output_format & (DIFF_FORMAT_NAME |
4588                                       DIFF_FORMAT_NAME_STATUS |
4589                                       DIFF_FORMAT_CHECKDIFF |
4590                                       DIFF_FORMAT_NO_OUTPUT))
4591                 options->output_format &= ~(DIFF_FORMAT_RAW |
4592                                             DIFF_FORMAT_NUMSTAT |
4593                                             DIFF_FORMAT_DIFFSTAT |
4594                                             DIFF_FORMAT_SHORTSTAT |
4595                                             DIFF_FORMAT_DIRSTAT |
4596                                             DIFF_FORMAT_SUMMARY |
4597                                             DIFF_FORMAT_PATCH);
4598
4599         /*
4600          * These cases always need recursive; we do not drop caller-supplied
4601          * recursive bits for other formats here.
4602          */
4603         if (options->output_format & (DIFF_FORMAT_PATCH |
4604                                       DIFF_FORMAT_NUMSTAT |
4605                                       DIFF_FORMAT_DIFFSTAT |
4606                                       DIFF_FORMAT_SHORTSTAT |
4607                                       DIFF_FORMAT_DIRSTAT |
4608                                       DIFF_FORMAT_SUMMARY |
4609                                       DIFF_FORMAT_CHECKDIFF))
4610                 options->flags.recursive = 1;
4611         /*
4612          * Also pickaxe would not work very well if you do not say recursive
4613          */
4614         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
4615                 options->flags.recursive = 1;
4616         /*
4617          * When patches are generated, submodules diffed against the work tree
4618          * must be checked for dirtiness too so it can be shown in the output
4619          */
4620         if (options->output_format & DIFF_FORMAT_PATCH)
4621                 options->flags.dirty_submodules = 1;
4622
4623         if (options->detect_rename && options->rename_limit < 0)
4624                 options->rename_limit = diff_rename_limit_default;
4625         if (hexsz < options->abbrev)
4626                 options->abbrev = hexsz; /* full */
4627
4628         /*
4629          * It does not make sense to show the first hit we happened
4630          * to have found.  It does not make sense not to return with
4631          * exit code in such a case either.
4632          */
4633         if (options->flags.quick) {
4634                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4635                 options->flags.exit_with_status = 1;
4636         }
4637
4638         options->diff_path_counter = 0;
4639
4640         if (options->flags.follow_renames && options->pathspec.nr != 1)
4641                 die(_("--follow requires exactly one pathspec"));
4642
4643         if (!options->use_color || external_diff())
4644                 options->color_moved = 0;
4645
4646         FREE_AND_NULL(options->parseopts);
4647 }
4648
4649 int parse_long_opt(const char *opt, const char **argv,
4650                    const char **optarg)
4651 {
4652         const char *arg = argv[0];
4653         if (!skip_prefix(arg, "--", &arg))
4654                 return 0;
4655         if (!skip_prefix(arg, opt, &arg))
4656                 return 0;
4657         if (*arg == '=') { /* stuck form: --option=value */
4658                 *optarg = arg + 1;
4659                 return 1;
4660         }
4661         if (*arg != '\0')
4662                 return 0;
4663         /* separate form: --option value */
4664         if (!argv[1])
4665                 die("Option '--%s' requires a value", opt);
4666         *optarg = argv[1];
4667         return 2;
4668 }
4669
4670 static int diff_opt_stat(const struct option *opt, const char *value, int unset)
4671 {
4672         struct diff_options *options = opt->value;
4673         int width = options->stat_width;
4674         int name_width = options->stat_name_width;
4675         int graph_width = options->stat_graph_width;
4676         int count = options->stat_count;
4677         char *end;
4678
4679         BUG_ON_OPT_NEG(unset);
4680
4681         if (!strcmp(opt->long_name, "stat")) {
4682                 if (value) {
4683                         width = strtoul(value, &end, 10);
4684                         if (*end == ',')
4685                                 name_width = strtoul(end+1, &end, 10);
4686                         if (*end == ',')
4687                                 count = strtoul(end+1, &end, 10);
4688                         if (*end)
4689                                 return error(_("invalid --stat value: %s"), value);
4690                 }
4691         } else if (!strcmp(opt->long_name, "stat-width")) {
4692                 width = strtoul(value, &end, 10);
4693                 if (*end)
4694                         return error(_("%s expects a numerical value"),
4695                                      opt->long_name);
4696         } else if (!strcmp(opt->long_name, "stat-name-width")) {
4697                 name_width = strtoul(value, &end, 10);
4698                 if (*end)
4699                         return error(_("%s expects a numerical value"),
4700                                      opt->long_name);
4701         } else if (!strcmp(opt->long_name, "stat-graph-width")) {
4702                 graph_width = strtoul(value, &end, 10);
4703                 if (*end)
4704                         return error(_("%s expects a numerical value"),
4705                                      opt->long_name);
4706         } else if (!strcmp(opt->long_name, "stat-count")) {
4707                 count = strtoul(value, &end, 10);
4708                 if (*end)
4709                         return error(_("%s expects a numerical value"),
4710                                      opt->long_name);
4711         } else
4712                 BUG("%s should not get here", opt->long_name);
4713
4714         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4715         options->stat_name_width = name_width;
4716         options->stat_graph_width = graph_width;
4717         options->stat_width = width;
4718         options->stat_count = count;
4719         return 0;
4720 }
4721
4722 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4723 {
4724         struct strbuf errmsg = STRBUF_INIT;
4725         if (parse_dirstat_params(options, params, &errmsg))
4726                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4727                     errmsg.buf);
4728         strbuf_release(&errmsg);
4729         /*
4730          * The caller knows a dirstat-related option is given from the command
4731          * line; allow it to say "return this_function();"
4732          */
4733         options->output_format |= DIFF_FORMAT_DIRSTAT;
4734         return 1;
4735 }
4736
4737 static const char diff_status_letters[] = {
4738         DIFF_STATUS_ADDED,
4739         DIFF_STATUS_COPIED,
4740         DIFF_STATUS_DELETED,
4741         DIFF_STATUS_MODIFIED,
4742         DIFF_STATUS_RENAMED,
4743         DIFF_STATUS_TYPE_CHANGED,
4744         DIFF_STATUS_UNKNOWN,
4745         DIFF_STATUS_UNMERGED,
4746         DIFF_STATUS_FILTER_AON,
4747         DIFF_STATUS_FILTER_BROKEN,
4748         '\0',
4749 };
4750
4751 static unsigned int filter_bit['Z' + 1];
4752
4753 static void prepare_filter_bits(void)
4754 {
4755         int i;
4756
4757         if (!filter_bit[DIFF_STATUS_ADDED]) {
4758                 for (i = 0; diff_status_letters[i]; i++)
4759                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4760         }
4761 }
4762
4763 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4764 {
4765         return opt->filter & filter_bit[(int) status];
4766 }
4767
4768 unsigned diff_filter_bit(char status)
4769 {
4770         prepare_filter_bits();
4771         return filter_bit[(int) status];
4772 }
4773
4774 static int diff_opt_diff_filter(const struct option *option,
4775                                 const char *optarg, int unset)
4776 {
4777         struct diff_options *opt = option->value;
4778         int i, optch;
4779
4780         BUG_ON_OPT_NEG(unset);
4781         prepare_filter_bits();
4782
4783         /*
4784          * If there is a negation e.g. 'd' in the input, and we haven't
4785          * initialized the filter field with another --diff-filter, start
4786          * from full set of bits, except for AON.
4787          */
4788         if (!opt->filter) {
4789                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4790                         if (optch < 'a' || 'z' < optch)
4791                                 continue;
4792                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4793                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4794                         break;
4795                 }
4796         }
4797
4798         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4799                 unsigned int bit;
4800                 int negate;
4801
4802                 if ('a' <= optch && optch <= 'z') {
4803                         negate = 1;
4804                         optch = toupper(optch);
4805                 } else {
4806                         negate = 0;
4807                 }
4808
4809                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4810                 if (!bit)
4811                         return error(_("unknown change class '%c' in --diff-filter=%s"),
4812                                      optarg[i], optarg);
4813                 if (negate)
4814                         opt->filter &= ~bit;
4815                 else
4816                         opt->filter |= bit;
4817         }
4818         return 0;
4819 }
4820
4821 static void enable_patch_output(int *fmt)
4822 {
4823         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4824         *fmt |= DIFF_FORMAT_PATCH;
4825 }
4826
4827 static int diff_opt_ws_error_highlight(const struct option *option,
4828                                        const char *arg, int unset)
4829 {
4830         struct diff_options *opt = option->value;
4831         int val = parse_ws_error_highlight(arg);
4832
4833         BUG_ON_OPT_NEG(unset);
4834         if (val < 0)
4835                 return error(_("unknown value after ws-error-highlight=%.*s"),
4836                              -1 - val, arg);
4837         opt->ws_error_highlight = val;
4838         return 0;
4839 }
4840
4841 static int diff_opt_find_object(const struct option *option,
4842                                 const char *arg, int unset)
4843 {
4844         struct diff_options *opt = option->value;
4845         struct object_id oid;
4846
4847         BUG_ON_OPT_NEG(unset);
4848         if (get_oid(arg, &oid))
4849                 return error(_("unable to resolve '%s'"), arg);
4850
4851         if (!opt->objfind)
4852                 opt->objfind = xcalloc(1, sizeof(*opt->objfind));
4853
4854         opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND;
4855         opt->flags.recursive = 1;
4856         opt->flags.tree_in_recursive = 1;
4857         oidset_insert(opt->objfind, &oid);
4858         return 0;
4859 }
4860
4861 static int diff_opt_anchored(const struct option *opt,
4862                              const char *arg, int unset)
4863 {
4864         struct diff_options *options = opt->value;
4865
4866         BUG_ON_OPT_NEG(unset);
4867         options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4868         ALLOC_GROW(options->anchors, options->anchors_nr + 1,
4869                    options->anchors_alloc);
4870         options->anchors[options->anchors_nr++] = xstrdup(arg);
4871         return 0;
4872 }
4873
4874 static int diff_opt_binary(const struct option *opt,
4875                            const char *arg, int unset)
4876 {
4877         struct diff_options *options = opt->value;
4878
4879         BUG_ON_OPT_NEG(unset);
4880         BUG_ON_OPT_ARG(arg);
4881         enable_patch_output(&options->output_format);
4882         options->flags.binary = 1;
4883         return 0;
4884 }
4885
4886 static int diff_opt_break_rewrites(const struct option *opt,
4887                                    const char *arg, int unset)
4888 {
4889         int *break_opt = opt->value;
4890         int opt1, opt2;
4891
4892         BUG_ON_OPT_NEG(unset);
4893         if (!arg)
4894                 arg = "";
4895         opt1 = parse_rename_score(&arg);
4896         if (*arg == 0)
4897                 opt2 = 0;
4898         else if (*arg != '/')
4899                 return error(_("%s expects <n>/<m> form"), opt->long_name);
4900         else {
4901                 arg++;
4902                 opt2 = parse_rename_score(&arg);
4903         }
4904         if (*arg != 0)
4905                 return error(_("%s expects <n>/<m> form"), opt->long_name);
4906         *break_opt = opt1 | (opt2 << 16);
4907         return 0;
4908 }
4909
4910 static int diff_opt_char(const struct option *opt,
4911                          const char *arg, int unset)
4912 {
4913         char *value = opt->value;
4914
4915         BUG_ON_OPT_NEG(unset);
4916         if (arg[1])
4917                 return error(_("%s expects a character, got '%s'"),
4918                              opt->long_name, arg);
4919         *value = arg[0];
4920         return 0;
4921 }
4922
4923 static int diff_opt_color_moved(const struct option *opt,
4924                                 const char *arg, int unset)
4925 {
4926         struct diff_options *options = opt->value;
4927
4928         if (unset) {
4929                 options->color_moved = COLOR_MOVED_NO;
4930         } else if (!arg) {
4931                 if (diff_color_moved_default)
4932                         options->color_moved = diff_color_moved_default;
4933                 if (options->color_moved == COLOR_MOVED_NO)
4934                         options->color_moved = COLOR_MOVED_DEFAULT;
4935         } else {
4936                 int cm = parse_color_moved(arg);
4937                 if (cm < 0)
4938                         return error(_("bad --color-moved argument: %s"), arg);
4939                 options->color_moved = cm;
4940         }
4941         return 0;
4942 }
4943
4944 static int diff_opt_color_moved_ws(const struct option *opt,
4945                                    const char *arg, int unset)
4946 {
4947         struct diff_options *options = opt->value;
4948         unsigned cm;
4949
4950         if (unset) {
4951                 options->color_moved_ws_handling = 0;
4952                 return 0;
4953         }
4954
4955         cm = parse_color_moved_ws(arg);
4956         if (cm & COLOR_MOVED_WS_ERROR)
4957                 return error(_("invalid mode '%s' in --color-moved-ws"), arg);
4958         options->color_moved_ws_handling = cm;
4959         return 0;
4960 }
4961
4962 static int diff_opt_color_words(const struct option *opt,
4963                                 const char *arg, int unset)
4964 {
4965         struct diff_options *options = opt->value;
4966
4967         BUG_ON_OPT_NEG(unset);
4968         options->use_color = 1;
4969         options->word_diff = DIFF_WORDS_COLOR;
4970         options->word_regex = arg;
4971         return 0;
4972 }
4973
4974 static int diff_opt_compact_summary(const struct option *opt,
4975                                     const char *arg, int unset)
4976 {
4977         struct diff_options *options = opt->value;
4978
4979         BUG_ON_OPT_ARG(arg);
4980         if (unset) {
4981                 options->flags.stat_with_summary = 0;
4982         } else {
4983                 options->flags.stat_with_summary = 1;
4984                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
4985         }
4986         return 0;
4987 }
4988
4989 static int diff_opt_diff_algorithm(const struct option *opt,
4990                                    const char *arg, int unset)
4991 {
4992         struct diff_options *options = opt->value;
4993         long value = parse_algorithm_value(arg);
4994
4995         BUG_ON_OPT_NEG(unset);
4996         if (value < 0)
4997                 return error(_("option diff-algorithm accepts \"myers\", "
4998                                "\"minimal\", \"patience\" and \"histogram\""));
4999
5000         /* clear out previous settings */
5001         DIFF_XDL_CLR(options, NEED_MINIMAL);
5002         options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
5003         options->xdl_opts |= value;
5004         return 0;
5005 }
5006
5007 static int diff_opt_dirstat(const struct option *opt,
5008                             const char *arg, int unset)
5009 {
5010         struct diff_options *options = opt->value;
5011
5012         BUG_ON_OPT_NEG(unset);
5013         if (!strcmp(opt->long_name, "cumulative")) {
5014                 if (arg)
5015                         BUG("how come --cumulative take a value?");
5016                 arg = "cumulative";
5017         } else if (!strcmp(opt->long_name, "dirstat-by-file"))
5018                 parse_dirstat_opt(options, "files");
5019         parse_dirstat_opt(options, arg ? arg : "");
5020         return 0;
5021 }
5022
5023 static int diff_opt_find_copies(const struct option *opt,
5024                                 const char *arg, int unset)
5025 {
5026         struct diff_options *options = opt->value;
5027
5028         BUG_ON_OPT_NEG(unset);
5029         if (!arg)
5030                 arg = "";
5031         options->rename_score = parse_rename_score(&arg);
5032         if (*arg != 0)
5033                 return error(_("invalid argument to %s"), opt->long_name);
5034
5035         if (options->detect_rename == DIFF_DETECT_COPY)
5036                 options->flags.find_copies_harder = 1;
5037         else
5038                 options->detect_rename = DIFF_DETECT_COPY;
5039
5040         return 0;
5041 }
5042
5043 static int diff_opt_find_renames(const struct option *opt,
5044                                  const char *arg, int unset)
5045 {
5046         struct diff_options *options = opt->value;
5047
5048         BUG_ON_OPT_NEG(unset);
5049         if (!arg)
5050                 arg = "";
5051         options->rename_score = parse_rename_score(&arg);
5052         if (*arg != 0)
5053                 return error(_("invalid argument to %s"), opt->long_name);
5054
5055         options->detect_rename = DIFF_DETECT_RENAME;
5056         return 0;
5057 }
5058
5059 static int diff_opt_follow(const struct option *opt,
5060                            const char *arg, int unset)
5061 {
5062         struct diff_options *options = opt->value;
5063
5064         BUG_ON_OPT_ARG(arg);
5065         if (unset) {
5066                 options->flags.follow_renames = 0;
5067                 options->flags.default_follow_renames = 0;
5068         } else {
5069                 options->flags.follow_renames = 1;
5070         }
5071         return 0;
5072 }
5073
5074 static int diff_opt_ignore_submodules(const struct option *opt,
5075                                       const char *arg, int unset)
5076 {
5077         struct diff_options *options = opt->value;
5078
5079         BUG_ON_OPT_NEG(unset);
5080         if (!arg)
5081                 arg = "all";
5082         options->flags.override_submodule_config = 1;
5083         handle_ignore_submodules_arg(options, arg);
5084         return 0;
5085 }
5086
5087 static int diff_opt_line_prefix(const struct option *opt,
5088                                 const char *optarg, int unset)
5089 {
5090         struct diff_options *options = opt->value;
5091
5092         BUG_ON_OPT_NEG(unset);
5093         options->line_prefix = optarg;
5094         options->line_prefix_length = strlen(options->line_prefix);
5095         graph_setup_line_prefix(options);
5096         return 0;
5097 }
5098
5099 static int diff_opt_no_prefix(const struct option *opt,
5100                               const char *optarg, int unset)
5101 {
5102         struct diff_options *options = opt->value;
5103
5104         BUG_ON_OPT_NEG(unset);
5105         BUG_ON_OPT_ARG(optarg);
5106         options->a_prefix = "";
5107         options->b_prefix = "";
5108         return 0;
5109 }
5110
5111 static enum parse_opt_result diff_opt_output(struct parse_opt_ctx_t *ctx,
5112                                              const struct option *opt,
5113                                              const char *arg, int unset)
5114 {
5115         struct diff_options *options = opt->value;
5116         char *path;
5117
5118         BUG_ON_OPT_NEG(unset);
5119         path = prefix_filename(ctx->prefix, arg);
5120         options->file = xfopen(path, "w");
5121         options->close_file = 1;
5122         if (options->use_color != GIT_COLOR_ALWAYS)
5123                 options->use_color = GIT_COLOR_NEVER;
5124         free(path);
5125         return 0;
5126 }
5127
5128 static int diff_opt_patience(const struct option *opt,
5129                              const char *arg, int unset)
5130 {
5131         struct diff_options *options = opt->value;
5132         int i;
5133
5134         BUG_ON_OPT_NEG(unset);
5135         BUG_ON_OPT_ARG(arg);
5136         options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
5137         /*
5138          * Both --patience and --anchored use PATIENCE_DIFF
5139          * internally, so remove any anchors previously
5140          * specified.
5141          */
5142         for (i = 0; i < options->anchors_nr; i++)
5143                 free(options->anchors[i]);
5144         options->anchors_nr = 0;
5145         return 0;
5146 }
5147
5148 static int diff_opt_pickaxe_regex(const struct option *opt,
5149                                   const char *arg, int unset)
5150 {
5151         struct diff_options *options = opt->value;
5152
5153         BUG_ON_OPT_NEG(unset);
5154         options->pickaxe = arg;
5155         options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
5156         return 0;
5157 }
5158
5159 static int diff_opt_pickaxe_string(const struct option *opt,
5160                                    const char *arg, int unset)
5161 {
5162         struct diff_options *options = opt->value;
5163
5164         BUG_ON_OPT_NEG(unset);
5165         options->pickaxe = arg;
5166         options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
5167         return 0;
5168 }
5169
5170 static int diff_opt_relative(const struct option *opt,
5171                              const char *arg, int unset)
5172 {
5173         struct diff_options *options = opt->value;
5174
5175         BUG_ON_OPT_NEG(unset);
5176         options->flags.relative_name = 1;
5177         if (arg)
5178                 options->prefix = arg;
5179         return 0;
5180 }
5181
5182 static int diff_opt_submodule(const struct option *opt,
5183                               const char *arg, int unset)
5184 {
5185         struct diff_options *options = opt->value;
5186
5187         BUG_ON_OPT_NEG(unset);
5188         if (!arg)
5189                 arg = "log";
5190         if (parse_submodule_params(options, arg))
5191                 return error(_("failed to parse --submodule option parameter: '%s'"),
5192                              arg);
5193         return 0;
5194 }
5195
5196 static int diff_opt_textconv(const struct option *opt,
5197                              const char *arg, int unset)
5198 {
5199         struct diff_options *options = opt->value;
5200
5201         BUG_ON_OPT_ARG(arg);
5202         if (unset) {
5203                 options->flags.allow_textconv = 0;
5204         } else {
5205                 options->flags.allow_textconv = 1;
5206                 options->flags.textconv_set_via_cmdline = 1;
5207         }
5208         return 0;
5209 }
5210
5211 static int diff_opt_unified(const struct option *opt,
5212                             const char *arg, int unset)
5213 {
5214         struct diff_options *options = opt->value;
5215         char *s;
5216
5217         BUG_ON_OPT_NEG(unset);
5218
5219         if (arg) {
5220                 options->context = strtol(arg, &s, 10);
5221                 if (*s)
5222                         return error(_("%s expects a numerical value"), "--unified");
5223         }
5224         enable_patch_output(&options->output_format);
5225
5226         return 0;
5227 }
5228
5229 static int diff_opt_word_diff(const struct option *opt,
5230                               const char *arg, int unset)
5231 {
5232         struct diff_options *options = opt->value;
5233
5234         BUG_ON_OPT_NEG(unset);
5235         if (arg) {
5236                 if (!strcmp(arg, "plain"))
5237                         options->word_diff = DIFF_WORDS_PLAIN;
5238                 else if (!strcmp(arg, "color")) {
5239                         options->use_color = 1;
5240                         options->word_diff = DIFF_WORDS_COLOR;
5241                 }
5242                 else if (!strcmp(arg, "porcelain"))
5243                         options->word_diff = DIFF_WORDS_PORCELAIN;
5244                 else if (!strcmp(arg, "none"))
5245                         options->word_diff = DIFF_WORDS_NONE;
5246                 else
5247                         return error(_("bad --word-diff argument: %s"), arg);
5248         } else {
5249                 if (options->word_diff == DIFF_WORDS_NONE)
5250                         options->word_diff = DIFF_WORDS_PLAIN;
5251         }
5252         return 0;
5253 }
5254
5255 static int diff_opt_word_diff_regex(const struct option *opt,
5256                                     const char *arg, int unset)
5257 {
5258         struct diff_options *options = opt->value;
5259
5260         BUG_ON_OPT_NEG(unset);
5261         if (options->word_diff == DIFF_WORDS_NONE)
5262                 options->word_diff = DIFF_WORDS_PLAIN;
5263         options->word_regex = arg;
5264         return 0;
5265 }
5266
5267 static void prep_parse_options(struct diff_options *options)
5268 {
5269         struct option parseopts[] = {
5270                 OPT_GROUP(N_("Diff output format options")),
5271                 OPT_BITOP('p', "patch", &options->output_format,
5272                           N_("generate patch"),
5273                           DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
5274                 OPT_BIT_F('s', "no-patch", &options->output_format,
5275                           N_("suppress diff output"),
5276                           DIFF_FORMAT_NO_OUTPUT, PARSE_OPT_NONEG),
5277                 OPT_BITOP('u', NULL, &options->output_format,
5278                           N_("generate patch"),
5279                           DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
5280                 OPT_CALLBACK_F('U', "unified", options, N_("<n>"),
5281                                N_("generate diffs with <n> lines context"),
5282                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_unified),
5283                 OPT_BOOL('W', "function-context", &options->flags.funccontext,
5284                          N_("generate diffs with <n> lines context")),
5285                 OPT_BIT_F(0, "raw", &options->output_format,
5286                           N_("generate the diff in raw format"),
5287                           DIFF_FORMAT_RAW, PARSE_OPT_NONEG),
5288                 OPT_BITOP(0, "patch-with-raw", &options->output_format,
5289                           N_("synonym for '-p --raw'"),
5290                           DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW,
5291                           DIFF_FORMAT_NO_OUTPUT),
5292                 OPT_BITOP(0, "patch-with-stat", &options->output_format,
5293                           N_("synonym for '-p --stat'"),
5294                           DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT,
5295                           DIFF_FORMAT_NO_OUTPUT),
5296                 OPT_BIT_F(0, "numstat", &options->output_format,
5297                           N_("machine friendly --stat"),
5298                           DIFF_FORMAT_NUMSTAT, PARSE_OPT_NONEG),
5299                 OPT_BIT_F(0, "shortstat", &options->output_format,
5300                           N_("output only the last line of --stat"),
5301                           DIFF_FORMAT_SHORTSTAT, PARSE_OPT_NONEG),
5302                 OPT_CALLBACK_F('X', "dirstat", options, N_("<param1,param2>..."),
5303                                N_("output the distribution of relative amount of changes for each sub-directory"),
5304                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5305                                diff_opt_dirstat),
5306                 OPT_CALLBACK_F(0, "cumulative", options, NULL,
5307                                N_("synonym for --dirstat=cumulative"),
5308                                PARSE_OPT_NONEG | PARSE_OPT_NOARG,
5309                                diff_opt_dirstat),
5310                 OPT_CALLBACK_F(0, "dirstat-by-file", options, N_("<param1,param2>..."),
5311                                N_("synonym for --dirstat=files,param1,param2..."),
5312                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5313                                diff_opt_dirstat),
5314                 OPT_BIT_F(0, "check", &options->output_format,
5315                           N_("warn if changes introduce conflict markers or whitespace errors"),
5316                           DIFF_FORMAT_CHECKDIFF, PARSE_OPT_NONEG),
5317                 OPT_BIT_F(0, "summary", &options->output_format,
5318                           N_("condensed summary such as creations, renames and mode changes"),
5319                           DIFF_FORMAT_SUMMARY, PARSE_OPT_NONEG),
5320                 OPT_BIT_F(0, "name-only", &options->output_format,
5321                           N_("show only names of changed files"),
5322                           DIFF_FORMAT_NAME, PARSE_OPT_NONEG),
5323                 OPT_BIT_F(0, "name-status", &options->output_format,
5324                           N_("show only names and status of changed files"),
5325                           DIFF_FORMAT_NAME_STATUS, PARSE_OPT_NONEG),
5326                 OPT_CALLBACK_F(0, "stat", options, N_("<width>[,<name-width>[,<count>]]"),
5327                                N_("generate diffstat"),
5328                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_stat),
5329                 OPT_CALLBACK_F(0, "stat-width", options, N_("<width>"),
5330                                N_("generate diffstat with a given width"),
5331                                PARSE_OPT_NONEG, diff_opt_stat),
5332                 OPT_CALLBACK_F(0, "stat-name-width", options, N_("<width>"),
5333                                N_("generate diffstat with a given name width"),
5334                                PARSE_OPT_NONEG, diff_opt_stat),
5335                 OPT_CALLBACK_F(0, "stat-graph-width", options, N_("<width>"),
5336                                N_("generate diffstat with a given graph width"),
5337                                PARSE_OPT_NONEG, diff_opt_stat),
5338                 OPT_CALLBACK_F(0, "stat-count", options, N_("<count>"),
5339                                N_("generate diffstat with limited lines"),
5340                                PARSE_OPT_NONEG, diff_opt_stat),
5341                 OPT_CALLBACK_F(0, "compact-summary", options, NULL,
5342                                N_("generate compact summary in diffstat"),
5343                                PARSE_OPT_NOARG, diff_opt_compact_summary),
5344                 OPT_CALLBACK_F(0, "binary", options, NULL,
5345                                N_("output a binary diff that can be applied"),
5346                                PARSE_OPT_NONEG | PARSE_OPT_NOARG, diff_opt_binary),
5347                 OPT_BOOL(0, "full-index", &options->flags.full_index,
5348                          N_("show full pre- and post-image object names on the \"index\" lines")),
5349                 OPT_COLOR_FLAG(0, "color", &options->use_color,
5350                                N_("show colored diff")),
5351                 OPT_CALLBACK_F(0, "ws-error-highlight", options, N_("<kind>"),
5352                                N_("highlight whitespace errors in the 'context', 'old' or 'new' lines in the diff"),
5353                                PARSE_OPT_NONEG, diff_opt_ws_error_highlight),
5354                 OPT_SET_INT('z', NULL, &options->line_termination,
5355                             N_("do not munge pathnames and use NULs as output field terminators in --raw or --numstat"),
5356                             0),
5357                 OPT__ABBREV(&options->abbrev),
5358                 OPT_STRING_F(0, "src-prefix", &options->a_prefix, N_("<prefix>"),
5359                              N_("show the given source prefix instead of \"a/\""),
5360                              PARSE_OPT_NONEG),
5361                 OPT_STRING_F(0, "dst-prefix", &options->b_prefix, N_("<prefix>"),
5362                              N_("show the given destination prefix instead of \"b/\""),
5363                              PARSE_OPT_NONEG),
5364                 OPT_CALLBACK_F(0, "line-prefix", options, N_("<prefix>"),
5365                                N_("prepend an additional prefix to every line of output"),
5366                                PARSE_OPT_NONEG, diff_opt_line_prefix),
5367                 OPT_CALLBACK_F(0, "no-prefix", options, NULL,
5368                                N_("do not show any source or destination prefix"),
5369                                PARSE_OPT_NONEG | PARSE_OPT_NOARG, diff_opt_no_prefix),
5370                 OPT_INTEGER_F(0, "inter-hunk-context", &options->interhunkcontext,
5371                               N_("show context between diff hunks up to the specified number of lines"),
5372                               PARSE_OPT_NONEG),
5373                 OPT_CALLBACK_F(0, "output-indicator-new",
5374                                &options->output_indicators[OUTPUT_INDICATOR_NEW],
5375                                N_("<char>"),
5376                                N_("specify the character to indicate a new line instead of '+'"),
5377                                PARSE_OPT_NONEG, diff_opt_char),
5378                 OPT_CALLBACK_F(0, "output-indicator-old",
5379                                &options->output_indicators[OUTPUT_INDICATOR_OLD],
5380                                N_("<char>"),
5381                                N_("specify the character to indicate an old line instead of '-'"),
5382                                PARSE_OPT_NONEG, diff_opt_char),
5383                 OPT_CALLBACK_F(0, "output-indicator-context",
5384                                &options->output_indicators[OUTPUT_INDICATOR_CONTEXT],
5385                                N_("<char>"),
5386                                N_("specify the character to indicate a context instead of ' '"),
5387                                PARSE_OPT_NONEG, diff_opt_char),
5388
5389                 OPT_GROUP(N_("Diff rename options")),
5390                 OPT_CALLBACK_F('B', "break-rewrites", &options->break_opt, N_("<n>[/<m>]"),
5391                                N_("break complete rewrite changes into pairs of delete and create"),
5392                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5393                                diff_opt_break_rewrites),
5394                 OPT_CALLBACK_F('M', "find-renames", options, N_("<n>"),
5395                                N_("detect renames"),
5396                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5397                                diff_opt_find_renames),
5398                 OPT_SET_INT_F('D', "irreversible-delete", &options->irreversible_delete,
5399                               N_("omit the preimage for deletes"),
5400                               1, PARSE_OPT_NONEG),
5401                 OPT_CALLBACK_F('C', "find-copies", options, N_("<n>"),
5402                                N_("detect copies"),
5403                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5404                                diff_opt_find_copies),
5405                 OPT_BOOL(0, "find-copies-harder", &options->flags.find_copies_harder,
5406                          N_("use unmodified files as source to find copies")),
5407                 OPT_SET_INT_F(0, "no-renames", &options->detect_rename,
5408                               N_("disable rename detection"),
5409                               0, PARSE_OPT_NONEG),
5410                 OPT_BOOL(0, "rename-empty", &options->flags.rename_empty,
5411                          N_("use empty blobs as rename source")),
5412                 OPT_CALLBACK_F(0, "follow", options, NULL,
5413                                N_("continue listing the history of a file beyond renames"),
5414                                PARSE_OPT_NOARG, diff_opt_follow),
5415                 OPT_INTEGER('l', NULL, &options->rename_limit,
5416                             N_("prevent rename/copy detection if the number of rename/copy targets exceeds given limit")),
5417
5418                 OPT_GROUP(N_("Diff algorithm options")),
5419                 OPT_BIT(0, "minimal", &options->xdl_opts,
5420                         N_("produce the smallest possible diff"),
5421                         XDF_NEED_MINIMAL),
5422                 OPT_BIT_F('w', "ignore-all-space", &options->xdl_opts,
5423                           N_("ignore whitespace when comparing lines"),
5424                           XDF_IGNORE_WHITESPACE, PARSE_OPT_NONEG),
5425                 OPT_BIT_F('b', "ignore-space-change", &options->xdl_opts,
5426                           N_("ignore changes in amount of whitespace"),
5427                           XDF_IGNORE_WHITESPACE_CHANGE, PARSE_OPT_NONEG),
5428                 OPT_BIT_F(0, "ignore-space-at-eol", &options->xdl_opts,
5429                           N_("ignore changes in whitespace at EOL"),
5430                           XDF_IGNORE_WHITESPACE_AT_EOL, PARSE_OPT_NONEG),
5431                 OPT_BIT_F(0, "ignore-cr-at-eol", &options->xdl_opts,
5432                           N_("ignore carrier-return at the end of line"),
5433                           XDF_IGNORE_CR_AT_EOL, PARSE_OPT_NONEG),
5434                 OPT_BIT_F(0, "ignore-blank-lines", &options->xdl_opts,
5435                           N_("ignore changes whose lines are all blank"),
5436                           XDF_IGNORE_BLANK_LINES, PARSE_OPT_NONEG),
5437                 OPT_BIT(0, "indent-heuristic", &options->xdl_opts,
5438                         N_("heuristic to shift diff hunk boundaries for easy reading"),
5439                         XDF_INDENT_HEURISTIC),
5440                 OPT_CALLBACK_F(0, "patience", options, NULL,
5441                                N_("generate diff using the \"patience diff\" algorithm"),
5442                                PARSE_OPT_NONEG | PARSE_OPT_NOARG,
5443                                diff_opt_patience),
5444                 OPT_BITOP(0, "histogram", &options->xdl_opts,
5445                           N_("generate diff using the \"histogram diff\" algorithm"),
5446                           XDF_HISTOGRAM_DIFF, XDF_DIFF_ALGORITHM_MASK),
5447                 OPT_CALLBACK_F(0, "diff-algorithm", options, N_("<algorithm>"),
5448                                N_("choose a diff algorithm"),
5449                                PARSE_OPT_NONEG, diff_opt_diff_algorithm),
5450                 OPT_CALLBACK_F(0, "anchored", options, N_("<text>"),
5451                                N_("generate diff using the \"anchored diff\" algorithm"),
5452                                PARSE_OPT_NONEG, diff_opt_anchored),
5453                 OPT_CALLBACK_F(0, "word-diff", options, N_("<mode>"),
5454                                N_("show word diff, using <mode> to delimit changed words"),
5455                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_word_diff),
5456                 OPT_CALLBACK_F(0, "word-diff-regex", options, N_("<regex>"),
5457                                N_("use <regex> to decide what a word is"),
5458                                PARSE_OPT_NONEG, diff_opt_word_diff_regex),
5459                 OPT_CALLBACK_F(0, "color-words", options, N_("<regex>"),
5460                                N_("equivalent to --word-diff=color --word-diff-regex=<regex>"),
5461                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_color_words),
5462                 OPT_CALLBACK_F(0, "color-moved", options, N_("<mode>"),
5463                                N_("moved lines of code are colored differently"),
5464                                PARSE_OPT_OPTARG, diff_opt_color_moved),
5465                 OPT_CALLBACK_F(0, "color-moved-ws", options, N_("<mode>"),
5466                                N_("how white spaces are ignored in --color-moved"),
5467                                0, diff_opt_color_moved_ws),
5468
5469                 OPT_GROUP(N_("Other diff options")),
5470                 OPT_CALLBACK_F(0, "relative", options, N_("<prefix>"),
5471                                N_("when run from subdir, exclude changes outside and show relative paths"),
5472                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5473                                diff_opt_relative),
5474                 OPT_BOOL('a', "text", &options->flags.text,
5475                          N_("treat all files as text")),
5476                 OPT_BOOL('R', NULL, &options->flags.reverse_diff,
5477                          N_("swap two inputs, reverse the diff")),
5478                 OPT_BOOL(0, "exit-code", &options->flags.exit_with_status,
5479                          N_("exit with 1 if there were differences, 0 otherwise")),
5480                 OPT_BOOL(0, "quiet", &options->flags.quick,
5481                          N_("disable all output of the program")),
5482                 OPT_BOOL(0, "ext-diff", &options->flags.allow_external,
5483                          N_("allow an external diff helper to be executed")),
5484                 OPT_CALLBACK_F(0, "textconv", options, NULL,
5485                                N_("run external text conversion filters when comparing binary files"),
5486                                PARSE_OPT_NOARG, diff_opt_textconv),
5487                 OPT_CALLBACK_F(0, "ignore-submodules", options, N_("<when>"),
5488                                N_("ignore changes to submodules in the diff generation"),
5489                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5490                                diff_opt_ignore_submodules),
5491                 OPT_CALLBACK_F(0, "submodule", options, N_("<format>"),
5492                                N_("specify how differences in submodules are shown"),
5493                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
5494                                diff_opt_submodule),
5495                 OPT_SET_INT_F(0, "ita-invisible-in-index", &options->ita_invisible_in_index,
5496                               N_("hide 'git add -N' entries from the index"),
5497                               1, PARSE_OPT_NONEG),
5498                 OPT_SET_INT_F(0, "ita-visible-in-index", &options->ita_invisible_in_index,
5499                               N_("treat 'git add -N' entries as real in the index"),
5500                               0, PARSE_OPT_NONEG),
5501                 OPT_CALLBACK_F('S', NULL, options, N_("<string>"),
5502                                N_("look for differences that change the number of occurrences of the specified string"),
5503                                0, diff_opt_pickaxe_string),
5504                 OPT_CALLBACK_F('G', NULL, options, N_("<regex>"),
5505                                N_("look for differences that change the number of occurrences of the specified regex"),
5506                                0, diff_opt_pickaxe_regex),
5507                 OPT_BIT_F(0, "pickaxe-all", &options->pickaxe_opts,
5508                           N_("show all changes in the changeset with -S or -G"),
5509                           DIFF_PICKAXE_ALL, PARSE_OPT_NONEG),
5510                 OPT_BIT_F(0, "pickaxe-regex", &options->pickaxe_opts,
5511                           N_("treat <string> in -S as extended POSIX regular expression"),
5512                           DIFF_PICKAXE_REGEX, PARSE_OPT_NONEG),
5513                 OPT_FILENAME('O', NULL, &options->orderfile,
5514                              N_("control the order in which files appear in the output")),
5515                 OPT_CALLBACK_F(0, "find-object", options, N_("<object-id>"),
5516                                N_("look for differences that change the number of occurrences of the specified object"),
5517                                PARSE_OPT_NONEG, diff_opt_find_object),
5518                 OPT_CALLBACK_F(0, "diff-filter", options, N_("[(A|C|D|M|R|T|U|X|B)...[*]]"),
5519                                N_("select files by diff type"),
5520                                PARSE_OPT_NONEG, diff_opt_diff_filter),
5521                 { OPTION_CALLBACK, 0, "output", options, N_("<file>"),
5522                   N_("Output to a specific file"),
5523                   PARSE_OPT_NONEG, NULL, 0, diff_opt_output },
5524
5525                 OPT_END()
5526         };
5527
5528         ALLOC_ARRAY(options->parseopts, ARRAY_SIZE(parseopts));
5529         memcpy(options->parseopts, parseopts, sizeof(parseopts));
5530 }
5531
5532 int diff_opt_parse(struct diff_options *options,
5533                    const char **av, int ac, const char *prefix)
5534 {
5535         if (!prefix)
5536                 prefix = "";
5537
5538         ac = parse_options(ac, av, prefix, options->parseopts, NULL,
5539                            PARSE_OPT_KEEP_DASHDASH |
5540                            PARSE_OPT_KEEP_UNKNOWN |
5541                            PARSE_OPT_NO_INTERNAL_HELP |
5542                            PARSE_OPT_ONE_SHOT |
5543                            PARSE_OPT_STOP_AT_NON_OPTION);
5544
5545         return ac;
5546 }
5547
5548 int parse_rename_score(const char **cp_p)
5549 {
5550         unsigned long num, scale;
5551         int ch, dot;
5552         const char *cp = *cp_p;
5553
5554         num = 0;
5555         scale = 1;
5556         dot = 0;
5557         for (;;) {
5558                 ch = *cp;
5559                 if ( !dot && ch == '.' ) {
5560                         scale = 1;
5561                         dot = 1;
5562                 } else if ( ch == '%' ) {
5563                         scale = dot ? scale*100 : 100;
5564                         cp++;   /* % is always at the end */
5565                         break;
5566                 } else if ( ch >= '0' && ch <= '9' ) {
5567                         if ( scale < 100000 ) {
5568                                 scale *= 10;
5569                                 num = (num*10) + (ch-'0');
5570                         }
5571                 } else {
5572                         break;
5573                 }
5574                 cp++;
5575         }
5576         *cp_p = cp;
5577
5578         /* user says num divided by scale and we say internally that
5579          * is MAX_SCORE * num / scale.
5580          */
5581         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
5582 }
5583
5584 struct diff_queue_struct diff_queued_diff;
5585
5586 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
5587 {
5588         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
5589         queue->queue[queue->nr++] = dp;
5590 }
5591
5592 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
5593                                  struct diff_filespec *one,
5594                                  struct diff_filespec *two)
5595 {
5596         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
5597         dp->one = one;
5598         dp->two = two;
5599         if (queue)
5600                 diff_q(queue, dp);
5601         return dp;
5602 }
5603
5604 void diff_free_filepair(struct diff_filepair *p)
5605 {
5606         free_filespec(p->one);
5607         free_filespec(p->two);
5608         free(p);
5609 }
5610
5611 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
5612 {
5613         int abblen;
5614         const char *abbrev;
5615
5616         /* Do we want all 40 hex characters? */
5617         if (len == the_hash_algo->hexsz)
5618                 return oid_to_hex(oid);
5619
5620         /* An abbreviated value is fine, possibly followed by an ellipsis. */
5621         abbrev = diff_abbrev_oid(oid, len);
5622
5623         if (!print_sha1_ellipsis())
5624                 return abbrev;
5625
5626         abblen = strlen(abbrev);
5627
5628         /*
5629          * In well-behaved cases, where the abbreviated result is the
5630          * same as the requested length, append three dots after the
5631          * abbreviation (hence the whole logic is limited to the case
5632          * where abblen < 37); when the actual abbreviated result is a
5633          * bit longer than the requested length, we reduce the number
5634          * of dots so that they match the well-behaved ones.  However,
5635          * if the actual abbreviation is longer than the requested
5636          * length by more than three, we give up on aligning, and add
5637          * three dots anyway, to indicate that the output is not the
5638          * full object name.  Yes, this may be suboptimal, but this
5639          * appears only in "diff --raw --abbrev" output and it is not
5640          * worth the effort to change it now.  Note that this would
5641          * likely to work fine when the automatic sizing of default
5642          * abbreviation length is used--we would be fed -1 in "len" in
5643          * that case, and will end up always appending three-dots, but
5644          * the automatic sizing is supposed to give abblen that ensures
5645          * uniqueness across all objects (statistically speaking).
5646          */
5647         if (abblen < the_hash_algo->hexsz - 3) {
5648                 static char hex[GIT_MAX_HEXSZ + 1];
5649                 if (len < abblen && abblen <= len + 2)
5650                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
5651                 else
5652                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
5653                 return hex;
5654         }
5655
5656         return oid_to_hex(oid);
5657 }
5658
5659 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5660 {
5661         int line_termination = opt->line_termination;
5662         int inter_name_termination = line_termination ? '\t' : '\0';
5663
5664         fprintf(opt->file, "%s", diff_line_prefix(opt));
5665         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5666                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5667                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5668                 fprintf(opt->file, "%s ",
5669                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5670         }
5671         if (p->score) {
5672                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5673                         inter_name_termination);
5674         } else {
5675                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5676         }
5677
5678         if (p->status == DIFF_STATUS_COPIED ||
5679             p->status == DIFF_STATUS_RENAMED) {
5680                 const char *name_a, *name_b;
5681                 name_a = p->one->path;
5682                 name_b = p->two->path;
5683                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5684                 write_name_quoted(name_a, opt->file, inter_name_termination);
5685                 write_name_quoted(name_b, opt->file, line_termination);
5686         } else {
5687                 const char *name_a, *name_b;
5688                 name_a = p->one->mode ? p->one->path : p->two->path;
5689                 name_b = NULL;
5690                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5691                 write_name_quoted(name_a, opt->file, line_termination);
5692         }
5693 }
5694
5695 int diff_unmodified_pair(struct diff_filepair *p)
5696 {
5697         /* This function is written stricter than necessary to support
5698          * the currently implemented transformers, but the idea is to
5699          * let transformers to produce diff_filepairs any way they want,
5700          * and filter and clean them up here before producing the output.
5701          */
5702         struct diff_filespec *one = p->one, *two = p->two;
5703
5704         if (DIFF_PAIR_UNMERGED(p))
5705                 return 0; /* unmerged is interesting */
5706
5707         /* deletion, addition, mode or type change
5708          * and rename are all interesting.
5709          */
5710         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5711             DIFF_PAIR_MODE_CHANGED(p) ||
5712             strcmp(one->path, two->path))
5713                 return 0;
5714
5715         /* both are valid and point at the same path.  that is, we are
5716          * dealing with a change.
5717          */
5718         if (one->oid_valid && two->oid_valid &&
5719             oideq(&one->oid, &two->oid) &&
5720             !one->dirty_submodule && !two->dirty_submodule)
5721                 return 1; /* no change */
5722         if (!one->oid_valid && !two->oid_valid)
5723                 return 1; /* both look at the same file on the filesystem. */
5724         return 0;
5725 }
5726
5727 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5728 {
5729         if (diff_unmodified_pair(p))
5730                 return;
5731
5732         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5733             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5734                 return; /* no tree diffs in patch format */
5735
5736         run_diff(p, o);
5737 }
5738
5739 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5740                             struct diffstat_t *diffstat)
5741 {
5742         if (diff_unmodified_pair(p))
5743                 return;
5744
5745         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5746             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5747                 return; /* no useful stat for tree diffs */
5748
5749         run_diffstat(p, o, diffstat);
5750 }
5751
5752 static void diff_flush_checkdiff(struct diff_filepair *p,
5753                 struct diff_options *o)
5754 {
5755         if (diff_unmodified_pair(p))
5756                 return;
5757
5758         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5759             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5760                 return; /* nothing to check in tree diffs */
5761
5762         run_checkdiff(p, o);
5763 }
5764
5765 int diff_queue_is_empty(void)
5766 {
5767         struct diff_queue_struct *q = &diff_queued_diff;
5768         int i;
5769         for (i = 0; i < q->nr; i++)
5770                 if (!diff_unmodified_pair(q->queue[i]))
5771                         return 0;
5772         return 1;
5773 }
5774
5775 #if DIFF_DEBUG
5776 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5777 {
5778         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5779                 x, one ? one : "",
5780                 s->path,
5781                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5782                 s->mode,
5783                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5784         fprintf(stderr, "queue[%d] %s size %lu\n",
5785                 x, one ? one : "",
5786                 s->size);
5787 }
5788
5789 void diff_debug_filepair(const struct diff_filepair *p, int i)
5790 {
5791         diff_debug_filespec(p->one, i, "one");
5792         diff_debug_filespec(p->two, i, "two");
5793         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5794                 p->score, p->status ? p->status : '?',
5795                 p->one->rename_used, p->broken_pair);
5796 }
5797
5798 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5799 {
5800         int i;
5801         if (msg)
5802                 fprintf(stderr, "%s\n", msg);
5803         fprintf(stderr, "q->nr = %d\n", q->nr);
5804         for (i = 0; i < q->nr; i++) {
5805                 struct diff_filepair *p = q->queue[i];
5806                 diff_debug_filepair(p, i);
5807         }
5808 }
5809 #endif
5810
5811 static void diff_resolve_rename_copy(void)
5812 {
5813         int i;
5814         struct diff_filepair *p;
5815         struct diff_queue_struct *q = &diff_queued_diff;
5816
5817         diff_debug_queue("resolve-rename-copy", q);
5818
5819         for (i = 0; i < q->nr; i++) {
5820                 p = q->queue[i];
5821                 p->status = 0; /* undecided */
5822                 if (DIFF_PAIR_UNMERGED(p))
5823                         p->status = DIFF_STATUS_UNMERGED;
5824                 else if (!DIFF_FILE_VALID(p->one))
5825                         p->status = DIFF_STATUS_ADDED;
5826                 else if (!DIFF_FILE_VALID(p->two))
5827                         p->status = DIFF_STATUS_DELETED;
5828                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5829                         p->status = DIFF_STATUS_TYPE_CHANGED;
5830
5831                 /* from this point on, we are dealing with a pair
5832                  * whose both sides are valid and of the same type, i.e.
5833                  * either in-place edit or rename/copy edit.
5834                  */
5835                 else if (DIFF_PAIR_RENAME(p)) {
5836                         /*
5837                          * A rename might have re-connected a broken
5838                          * pair up, causing the pathnames to be the
5839                          * same again. If so, that's not a rename at
5840                          * all, just a modification..
5841                          *
5842                          * Otherwise, see if this source was used for
5843                          * multiple renames, in which case we decrement
5844                          * the count, and call it a copy.
5845                          */
5846                         if (!strcmp(p->one->path, p->two->path))
5847                                 p->status = DIFF_STATUS_MODIFIED;
5848                         else if (--p->one->rename_used > 0)
5849                                 p->status = DIFF_STATUS_COPIED;
5850                         else
5851                                 p->status = DIFF_STATUS_RENAMED;
5852                 }
5853                 else if (!oideq(&p->one->oid, &p->two->oid) ||
5854                          p->one->mode != p->two->mode ||
5855                          p->one->dirty_submodule ||
5856                          p->two->dirty_submodule ||
5857                          is_null_oid(&p->one->oid))
5858                         p->status = DIFF_STATUS_MODIFIED;
5859                 else {
5860                         /* This is a "no-change" entry and should not
5861                          * happen anymore, but prepare for broken callers.
5862                          */
5863                         error("feeding unmodified %s to diffcore",
5864                               p->one->path);
5865                         p->status = DIFF_STATUS_UNKNOWN;
5866                 }
5867         }
5868         diff_debug_queue("resolve-rename-copy done", q);
5869 }
5870
5871 static int check_pair_status(struct diff_filepair *p)
5872 {
5873         switch (p->status) {
5874         case DIFF_STATUS_UNKNOWN:
5875                 return 0;
5876         case 0:
5877                 die("internal error in diff-resolve-rename-copy");
5878         default:
5879                 return 1;
5880         }
5881 }
5882
5883 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5884 {
5885         int fmt = opt->output_format;
5886
5887         if (fmt & DIFF_FORMAT_CHECKDIFF)
5888                 diff_flush_checkdiff(p, opt);
5889         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5890                 diff_flush_raw(p, opt);
5891         else if (fmt & DIFF_FORMAT_NAME) {
5892                 const char *name_a, *name_b;
5893                 name_a = p->two->path;
5894                 name_b = NULL;
5895                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5896                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5897                 write_name_quoted(name_a, opt->file, opt->line_termination);
5898         }
5899 }
5900
5901 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5902 {
5903         struct strbuf sb = STRBUF_INIT;
5904         if (fs->mode)
5905                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5906         else
5907                 strbuf_addf(&sb, " %s ", newdelete);
5908
5909         quote_c_style(fs->path, &sb, NULL, 0);
5910         strbuf_addch(&sb, '\n');
5911         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5912                          sb.buf, sb.len, 0);
5913         strbuf_release(&sb);
5914 }
5915
5916 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5917                 int show_name)
5918 {
5919         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5920                 struct strbuf sb = STRBUF_INIT;
5921                 strbuf_addf(&sb, " mode change %06o => %06o",
5922                             p->one->mode, p->two->mode);
5923                 if (show_name) {
5924                         strbuf_addch(&sb, ' ');
5925                         quote_c_style(p->two->path, &sb, NULL, 0);
5926                 }
5927                 strbuf_addch(&sb, '\n');
5928                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5929                                  sb.buf, sb.len, 0);
5930                 strbuf_release(&sb);
5931         }
5932 }
5933
5934 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5935                 struct diff_filepair *p)
5936 {
5937         struct strbuf sb = STRBUF_INIT;
5938         struct strbuf names = STRBUF_INIT;
5939
5940         pprint_rename(&names, p->one->path, p->two->path);
5941         strbuf_addf(&sb, " %s %s (%d%%)\n",
5942                     renamecopy, names.buf, similarity_index(p));
5943         strbuf_release(&names);
5944         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5945                                  sb.buf, sb.len, 0);
5946         show_mode_change(opt, p, 0);
5947         strbuf_release(&sb);
5948 }
5949
5950 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5951 {
5952         switch(p->status) {
5953         case DIFF_STATUS_DELETED:
5954                 show_file_mode_name(opt, "delete", p->one);
5955                 break;
5956         case DIFF_STATUS_ADDED:
5957                 show_file_mode_name(opt, "create", p->two);
5958                 break;
5959         case DIFF_STATUS_COPIED:
5960                 show_rename_copy(opt, "copy", p);
5961                 break;
5962         case DIFF_STATUS_RENAMED:
5963                 show_rename_copy(opt, "rename", p);
5964                 break;
5965         default:
5966                 if (p->score) {
5967                         struct strbuf sb = STRBUF_INIT;
5968                         strbuf_addstr(&sb, " rewrite ");
5969                         quote_c_style(p->two->path, &sb, NULL, 0);
5970                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5971                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5972                                          sb.buf, sb.len, 0);
5973                         strbuf_release(&sb);
5974                 }
5975                 show_mode_change(opt, p, !p->score);
5976                 break;
5977         }
5978 }
5979
5980 struct patch_id_t {
5981         git_SHA_CTX *ctx;
5982         int patchlen;
5983 };
5984
5985 static int remove_space(char *line, int len)
5986 {
5987         int i;
5988         char *dst = line;
5989         unsigned char c;
5990
5991         for (i = 0; i < len; i++)
5992                 if (!isspace((c = line[i])))
5993                         *dst++ = c;
5994
5995         return dst - line;
5996 }
5997
5998 void flush_one_hunk(struct object_id *result, git_SHA_CTX *ctx)
5999 {
6000         unsigned char hash[GIT_MAX_RAWSZ];
6001         unsigned short carry = 0;
6002         int i;
6003
6004         git_SHA1_Final(hash, ctx);
6005         git_SHA1_Init(ctx);
6006         /* 20-byte sum, with carry */
6007         for (i = 0; i < GIT_SHA1_RAWSZ; ++i) {
6008                 carry += result->hash[i] + hash[i];
6009                 result->hash[i] = carry;
6010                 carry >>= 8;
6011         }
6012 }
6013
6014 static void patch_id_consume(void *priv, char *line, unsigned long len)
6015 {
6016         struct patch_id_t *data = priv;
6017         int new_len;
6018
6019         new_len = remove_space(line, len);
6020
6021         git_SHA1_Update(data->ctx, line, new_len);
6022         data->patchlen += new_len;
6023 }
6024
6025 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
6026 {
6027         git_SHA1_Update(ctx, str, strlen(str));
6028 }
6029
6030 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
6031 {
6032         /* large enough for 2^32 in octal */
6033         char buf[12];
6034         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
6035         git_SHA1_Update(ctx, buf, len);
6036 }
6037
6038 /* returns 0 upon success, and writes result into oid */
6039 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only, int stable)
6040 {
6041         struct diff_queue_struct *q = &diff_queued_diff;
6042         int i;
6043         git_SHA_CTX ctx;
6044         struct patch_id_t data;
6045
6046         git_SHA1_Init(&ctx);
6047         memset(&data, 0, sizeof(struct patch_id_t));
6048         data.ctx = &ctx;
6049         oidclr(oid);
6050
6051         for (i = 0; i < q->nr; i++) {
6052                 xpparam_t xpp;
6053                 xdemitconf_t xecfg;
6054                 mmfile_t mf1, mf2;
6055                 struct diff_filepair *p = q->queue[i];
6056                 int len1, len2;
6057
6058                 memset(&xpp, 0, sizeof(xpp));
6059                 memset(&xecfg, 0, sizeof(xecfg));
6060                 if (p->status == 0)
6061                         return error("internal diff status error");
6062                 if (p->status == DIFF_STATUS_UNKNOWN)
6063                         continue;
6064                 if (diff_unmodified_pair(p))
6065                         continue;
6066                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
6067                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
6068                         continue;
6069                 if (DIFF_PAIR_UNMERGED(p))
6070                         continue;
6071
6072                 diff_fill_oid_info(p->one, options->repo->index);
6073                 diff_fill_oid_info(p->two, options->repo->index);
6074
6075                 len1 = remove_space(p->one->path, strlen(p->one->path));
6076                 len2 = remove_space(p->two->path, strlen(p->two->path));
6077                 patch_id_add_string(&ctx, "diff--git");
6078                 patch_id_add_string(&ctx, "a/");
6079                 git_SHA1_Update(&ctx, p->one->path, len1);
6080                 patch_id_add_string(&ctx, "b/");
6081                 git_SHA1_Update(&ctx, p->two->path, len2);
6082
6083                 if (p->one->mode == 0) {
6084                         patch_id_add_string(&ctx, "newfilemode");
6085                         patch_id_add_mode(&ctx, p->two->mode);
6086                         patch_id_add_string(&ctx, "---/dev/null");
6087                         patch_id_add_string(&ctx, "+++b/");
6088                         git_SHA1_Update(&ctx, p->two->path, len2);
6089                 } else if (p->two->mode == 0) {
6090                         patch_id_add_string(&ctx, "deletedfilemode");
6091                         patch_id_add_mode(&ctx, p->one->mode);
6092                         patch_id_add_string(&ctx, "---a/");
6093                         git_SHA1_Update(&ctx, p->one->path, len1);
6094                         patch_id_add_string(&ctx, "+++/dev/null");
6095                 } else {
6096                         patch_id_add_string(&ctx, "---a/");
6097                         git_SHA1_Update(&ctx, p->one->path, len1);
6098                         patch_id_add_string(&ctx, "+++b/");
6099                         git_SHA1_Update(&ctx, p->two->path, len2);
6100                 }
6101
6102                 if (diff_header_only)
6103                         continue;
6104
6105                 if (fill_mmfile(options->repo, &mf1, p->one) < 0 ||
6106                     fill_mmfile(options->repo, &mf2, p->two) < 0)
6107                         return error("unable to read files to diff");
6108
6109                 if (diff_filespec_is_binary(options->repo, p->one) ||
6110                     diff_filespec_is_binary(options->repo, p->two)) {
6111                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
6112                                         GIT_SHA1_HEXSZ);
6113                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
6114                                         GIT_SHA1_HEXSZ);
6115                         continue;
6116                 }
6117
6118                 xpp.flags = 0;
6119                 xecfg.ctxlen = 3;
6120                 xecfg.flags = 0;
6121                 if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
6122                                   patch_id_consume, &data, &xpp, &xecfg))
6123                         return error("unable to generate patch-id diff for %s",
6124                                      p->one->path);
6125
6126                 if (stable)
6127                         flush_one_hunk(oid, &ctx);
6128         }
6129
6130         if (!stable)
6131                 git_SHA1_Final(oid->hash, &ctx);
6132
6133         return 0;
6134 }
6135
6136 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only, int stable)
6137 {
6138         struct diff_queue_struct *q = &diff_queued_diff;
6139         int i;
6140         int result = diff_get_patch_id(options, oid, diff_header_only, stable);
6141
6142         for (i = 0; i < q->nr; i++)
6143                 diff_free_filepair(q->queue[i]);
6144
6145         free(q->queue);
6146         DIFF_QUEUE_CLEAR(q);
6147
6148         return result;
6149 }
6150
6151 static int is_summary_empty(const struct diff_queue_struct *q)
6152 {
6153         int i;
6154
6155         for (i = 0; i < q->nr; i++) {
6156                 const struct diff_filepair *p = q->queue[i];
6157
6158                 switch (p->status) {
6159                 case DIFF_STATUS_DELETED:
6160                 case DIFF_STATUS_ADDED:
6161                 case DIFF_STATUS_COPIED:
6162                 case DIFF_STATUS_RENAMED:
6163                         return 0;
6164                 default:
6165                         if (p->score)
6166                                 return 0;
6167                         if (p->one->mode && p->two->mode &&
6168                             p->one->mode != p->two->mode)
6169                                 return 0;
6170                         break;
6171                 }
6172         }
6173         return 1;
6174 }
6175
6176 static const char rename_limit_warning[] =
6177 N_("inexact rename detection was skipped due to too many files.");
6178
6179 static const char degrade_cc_to_c_warning[] =
6180 N_("only found copies from modified paths due to too many files.");
6181
6182 static const char rename_limit_advice[] =
6183 N_("you may want to set your %s variable to at least "
6184    "%d and retry the command.");
6185
6186 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
6187 {
6188         fflush(stdout);
6189         if (degraded_cc)
6190                 warning(_(degrade_cc_to_c_warning));
6191         else if (needed)
6192                 warning(_(rename_limit_warning));
6193         else
6194                 return;
6195         if (0 < needed)
6196                 warning(_(rename_limit_advice), varname, needed);
6197 }
6198
6199 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
6200 {
6201         int i;
6202         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
6203         struct diff_queue_struct *q = &diff_queued_diff;
6204
6205         if (WSEH_NEW & WS_RULE_MASK)
6206                 BUG("WS rules bit mask overlaps with diff symbol flags");
6207
6208         if (o->color_moved)
6209                 o->emitted_symbols = &esm;
6210
6211         for (i = 0; i < q->nr; i++) {
6212                 struct diff_filepair *p = q->queue[i];
6213                 if (check_pair_status(p))
6214                         diff_flush_patch(p, o);
6215         }
6216
6217         if (o->emitted_symbols) {
6218                 if (o->color_moved) {
6219                         struct hashmap add_lines, del_lines;
6220
6221                         if (o->color_moved_ws_handling &
6222                             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
6223                                 o->color_moved_ws_handling |= XDF_IGNORE_WHITESPACE;
6224
6225                         hashmap_init(&del_lines, moved_entry_cmp, o, 0);
6226                         hashmap_init(&add_lines, moved_entry_cmp, o, 0);
6227
6228                         add_lines_to_move_detection(o, &add_lines, &del_lines);
6229                         mark_color_as_moved(o, &add_lines, &del_lines);
6230                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
6231                                 dim_moved_lines(o);
6232
6233                         hashmap_free(&add_lines, 1);
6234                         hashmap_free(&del_lines, 1);
6235                 }
6236
6237                 for (i = 0; i < esm.nr; i++)
6238                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
6239
6240                 for (i = 0; i < esm.nr; i++)
6241                         free((void *)esm.buf[i].line);
6242                 esm.nr = 0;
6243
6244                 o->emitted_symbols = NULL;
6245         }
6246 }
6247
6248 void diff_flush(struct diff_options *options)
6249 {
6250         struct diff_queue_struct *q = &diff_queued_diff;
6251         int i, output_format = options->output_format;
6252         int separator = 0;
6253         int dirstat_by_line = 0;
6254
6255         /*
6256          * Order: raw, stat, summary, patch
6257          * or:    name/name-status/checkdiff (other bits clear)
6258          */
6259         if (!q->nr)
6260                 goto free_queue;
6261
6262         if (output_format & (DIFF_FORMAT_RAW |
6263                              DIFF_FORMAT_NAME |
6264                              DIFF_FORMAT_NAME_STATUS |
6265                              DIFF_FORMAT_CHECKDIFF)) {
6266                 for (i = 0; i < q->nr; i++) {
6267                         struct diff_filepair *p = q->queue[i];
6268                         if (check_pair_status(p))
6269                                 flush_one_pair(p, options);
6270                 }
6271                 separator++;
6272         }
6273
6274         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
6275                 dirstat_by_line = 1;
6276
6277         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
6278             dirstat_by_line) {
6279                 struct diffstat_t diffstat;
6280
6281                 memset(&diffstat, 0, sizeof(struct diffstat_t));
6282                 for (i = 0; i < q->nr; i++) {
6283                         struct diff_filepair *p = q->queue[i];
6284                         if (check_pair_status(p))
6285                                 diff_flush_stat(p, options, &diffstat);
6286                 }
6287                 if (output_format & DIFF_FORMAT_NUMSTAT)
6288                         show_numstat(&diffstat, options);
6289                 if (output_format & DIFF_FORMAT_DIFFSTAT)
6290                         show_stats(&diffstat, options);
6291                 if (output_format & DIFF_FORMAT_SHORTSTAT)
6292                         show_shortstats(&diffstat, options);
6293                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
6294                         show_dirstat_by_line(&diffstat, options);
6295                 free_diffstat_info(&diffstat);
6296                 separator++;
6297         }
6298         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
6299                 show_dirstat(options);
6300
6301         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
6302                 for (i = 0; i < q->nr; i++) {
6303                         diff_summary(options, q->queue[i]);
6304                 }
6305                 separator++;
6306         }
6307
6308         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
6309             options->flags.exit_with_status &&
6310             options->flags.diff_from_contents) {
6311                 /*
6312                  * run diff_flush_patch for the exit status. setting
6313                  * options->file to /dev/null should be safe, because we
6314                  * aren't supposed to produce any output anyway.
6315                  */
6316                 if (options->close_file)
6317                         fclose(options->file);
6318                 options->file = xfopen("/dev/null", "w");
6319                 options->close_file = 1;
6320                 options->color_moved = 0;
6321                 for (i = 0; i < q->nr; i++) {
6322                         struct diff_filepair *p = q->queue[i];
6323                         if (check_pair_status(p))
6324                                 diff_flush_patch(p, options);
6325                         if (options->found_changes)
6326                                 break;
6327                 }
6328         }
6329
6330         if (output_format & DIFF_FORMAT_PATCH) {
6331                 if (separator) {
6332                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
6333                         if (options->stat_sep)
6334                                 /* attach patch instead of inline */
6335                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
6336                                                  NULL, 0, 0);
6337                 }
6338
6339                 diff_flush_patch_all_file_pairs(options);
6340         }
6341
6342         if (output_format & DIFF_FORMAT_CALLBACK)
6343                 options->format_callback(q, options, options->format_callback_data);
6344
6345         for (i = 0; i < q->nr; i++)
6346                 diff_free_filepair(q->queue[i]);
6347 free_queue:
6348         free(q->queue);
6349         DIFF_QUEUE_CLEAR(q);
6350         if (options->close_file)
6351                 fclose(options->file);
6352
6353         /*
6354          * Report the content-level differences with HAS_CHANGES;
6355          * diff_addremove/diff_change does not set the bit when
6356          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
6357          */
6358         if (options->flags.diff_from_contents) {
6359                 if (options->found_changes)
6360                         options->flags.has_changes = 1;
6361                 else
6362                         options->flags.has_changes = 0;
6363         }
6364 }
6365
6366 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
6367 {
6368         return (((p->status == DIFF_STATUS_MODIFIED) &&
6369                  ((p->score &&
6370                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
6371                   (!p->score &&
6372                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
6373                 ((p->status != DIFF_STATUS_MODIFIED) &&
6374                  filter_bit_tst(p->status, options)));
6375 }
6376
6377 static void diffcore_apply_filter(struct diff_options *options)
6378 {
6379         int i;
6380         struct diff_queue_struct *q = &diff_queued_diff;
6381         struct diff_queue_struct outq;
6382
6383         DIFF_QUEUE_CLEAR(&outq);
6384
6385         if (!options->filter)
6386                 return;
6387
6388         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
6389                 int found;
6390                 for (i = found = 0; !found && i < q->nr; i++) {
6391                         if (match_filter(options, q->queue[i]))
6392                                 found++;
6393                 }
6394                 if (found)
6395                         return;
6396
6397                 /* otherwise we will clear the whole queue
6398                  * by copying the empty outq at the end of this
6399                  * function, but first clear the current entries
6400                  * in the queue.
6401                  */
6402                 for (i = 0; i < q->nr; i++)
6403                         diff_free_filepair(q->queue[i]);
6404         }
6405         else {
6406                 /* Only the matching ones */
6407                 for (i = 0; i < q->nr; i++) {
6408                         struct diff_filepair *p = q->queue[i];
6409                         if (match_filter(options, p))
6410                                 diff_q(&outq, p);
6411                         else
6412                                 diff_free_filepair(p);
6413                 }
6414         }
6415         free(q->queue);
6416         *q = outq;
6417 }
6418
6419 /* Check whether two filespecs with the same mode and size are identical */
6420 static int diff_filespec_is_identical(struct repository *r,
6421                                       struct diff_filespec *one,
6422                                       struct diff_filespec *two)
6423 {
6424         if (S_ISGITLINK(one->mode))
6425                 return 0;
6426         if (diff_populate_filespec(r, one, 0))
6427                 return 0;
6428         if (diff_populate_filespec(r, two, 0))
6429                 return 0;
6430         return !memcmp(one->data, two->data, one->size);
6431 }
6432
6433 static int diff_filespec_check_stat_unmatch(struct repository *r,
6434                                             struct diff_filepair *p)
6435 {
6436         if (p->done_skip_stat_unmatch)
6437                 return p->skip_stat_unmatch_result;
6438
6439         p->done_skip_stat_unmatch = 1;
6440         p->skip_stat_unmatch_result = 0;
6441         /*
6442          * 1. Entries that come from stat info dirtiness
6443          *    always have both sides (iow, not create/delete),
6444          *    one side of the object name is unknown, with
6445          *    the same mode and size.  Keep the ones that
6446          *    do not match these criteria.  They have real
6447          *    differences.
6448          *
6449          * 2. At this point, the file is known to be modified,
6450          *    with the same mode and size, and the object
6451          *    name of one side is unknown.  Need to inspect
6452          *    the identical contents.
6453          */
6454         if (!DIFF_FILE_VALID(p->one) || /* (1) */
6455             !DIFF_FILE_VALID(p->two) ||
6456             (p->one->oid_valid && p->two->oid_valid) ||
6457             (p->one->mode != p->two->mode) ||
6458             diff_populate_filespec(r, p->one, CHECK_SIZE_ONLY) ||
6459             diff_populate_filespec(r, p->two, CHECK_SIZE_ONLY) ||
6460             (p->one->size != p->two->size) ||
6461             !diff_filespec_is_identical(r, p->one, p->two)) /* (2) */
6462                 p->skip_stat_unmatch_result = 1;
6463         return p->skip_stat_unmatch_result;
6464 }
6465
6466 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
6467 {
6468         int i;
6469         struct diff_queue_struct *q = &diff_queued_diff;
6470         struct diff_queue_struct outq;
6471         DIFF_QUEUE_CLEAR(&outq);
6472
6473         for (i = 0; i < q->nr; i++) {
6474                 struct diff_filepair *p = q->queue[i];
6475
6476                 if (diff_filespec_check_stat_unmatch(diffopt->repo, p))
6477                         diff_q(&outq, p);
6478                 else {
6479                         /*
6480                          * The caller can subtract 1 from skip_stat_unmatch
6481                          * to determine how many paths were dirty only
6482                          * due to stat info mismatch.
6483                          */
6484                         if (!diffopt->flags.no_index)
6485                                 diffopt->skip_stat_unmatch++;
6486                         diff_free_filepair(p);
6487                 }
6488         }
6489         free(q->queue);
6490         *q = outq;
6491 }
6492
6493 static int diffnamecmp(const void *a_, const void *b_)
6494 {
6495         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
6496         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
6497         const char *name_a, *name_b;
6498
6499         name_a = a->one ? a->one->path : a->two->path;
6500         name_b = b->one ? b->one->path : b->two->path;
6501         return strcmp(name_a, name_b);
6502 }
6503
6504 void diffcore_fix_diff_index(void)
6505 {
6506         struct diff_queue_struct *q = &diff_queued_diff;
6507         QSORT(q->queue, q->nr, diffnamecmp);
6508 }
6509
6510 static void add_if_missing(struct repository *r,
6511                            struct oid_array *to_fetch,
6512                            const struct diff_filespec *filespec)
6513 {
6514         if (filespec && filespec->oid_valid &&
6515             !S_ISGITLINK(filespec->mode) &&
6516             oid_object_info_extended(r, &filespec->oid, NULL,
6517                                      OBJECT_INFO_FOR_PREFETCH))
6518                 oid_array_append(to_fetch, &filespec->oid);
6519 }
6520
6521 void diffcore_std(struct diff_options *options)
6522 {
6523         if (options->repo == the_repository && has_promisor_remote()) {
6524                 /*
6525                  * Prefetch the diff pairs that are about to be flushed.
6526                  */
6527                 int i;
6528                 struct diff_queue_struct *q = &diff_queued_diff;
6529                 struct oid_array to_fetch = OID_ARRAY_INIT;
6530
6531                 for (i = 0; i < q->nr; i++) {
6532                         struct diff_filepair *p = q->queue[i];
6533                         add_if_missing(options->repo, &to_fetch, p->one);
6534                         add_if_missing(options->repo, &to_fetch, p->two);
6535                 }
6536                 if (to_fetch.nr)
6537                         /*
6538                          * NEEDSWORK: Consider deduplicating the OIDs sent.
6539                          */
6540                         promisor_remote_get_direct(options->repo,
6541                                                    to_fetch.oid, to_fetch.nr);
6542                 oid_array_clear(&to_fetch);
6543         }
6544
6545         /* NOTE please keep the following in sync with diff_tree_combined() */
6546         if (options->skip_stat_unmatch)
6547                 diffcore_skip_stat_unmatch(options);
6548         if (!options->found_follow) {
6549                 /* See try_to_follow_renames() in tree-diff.c */
6550                 if (options->break_opt != -1)
6551                         diffcore_break(options->repo,
6552                                        options->break_opt);
6553                 if (options->detect_rename)
6554                         diffcore_rename(options);
6555                 if (options->break_opt != -1)
6556                         diffcore_merge_broken();
6557         }
6558         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
6559                 diffcore_pickaxe(options);
6560         if (options->orderfile)
6561                 diffcore_order(options->orderfile);
6562         if (!options->found_follow)
6563                 /* See try_to_follow_renames() in tree-diff.c */
6564                 diff_resolve_rename_copy();
6565         diffcore_apply_filter(options);
6566
6567         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
6568                 options->flags.has_changes = 1;
6569         else
6570                 options->flags.has_changes = 0;
6571
6572         options->found_follow = 0;
6573 }
6574
6575 int diff_result_code(struct diff_options *opt, int status)
6576 {
6577         int result = 0;
6578
6579         diff_warn_rename_limit("diff.renameLimit",
6580                                opt->needed_rename_limit,
6581                                opt->degraded_cc_to_c);
6582         if (!opt->flags.exit_with_status &&
6583             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
6584                 return status;
6585         if (opt->flags.exit_with_status &&
6586             opt->flags.has_changes)
6587                 result |= 01;
6588         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
6589             opt->flags.check_failed)
6590                 result |= 02;
6591         return result;
6592 }
6593
6594 int diff_can_quit_early(struct diff_options *opt)
6595 {
6596         return (opt->flags.quick &&
6597                 !opt->filter &&
6598                 opt->flags.has_changes);
6599 }
6600
6601 /*
6602  * Shall changes to this submodule be ignored?
6603  *
6604  * Submodule changes can be configured to be ignored separately for each path,
6605  * but that configuration can be overridden from the command line.
6606  */
6607 static int is_submodule_ignored(const char *path, struct diff_options *options)
6608 {
6609         int ignored = 0;
6610         struct diff_flags orig_flags = options->flags;
6611         if (!options->flags.override_submodule_config)
6612                 set_diffopt_flags_from_submodule_config(options, path);
6613         if (options->flags.ignore_submodules)
6614                 ignored = 1;
6615         options->flags = orig_flags;
6616         return ignored;
6617 }
6618
6619 void diff_addremove(struct diff_options *options,
6620                     int addremove, unsigned mode,
6621                     const struct object_id *oid,
6622                     int oid_valid,
6623                     const char *concatpath, unsigned dirty_submodule)
6624 {
6625         struct diff_filespec *one, *two;
6626
6627         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
6628                 return;
6629
6630         /* This may look odd, but it is a preparation for
6631          * feeding "there are unchanged files which should
6632          * not produce diffs, but when you are doing copy
6633          * detection you would need them, so here they are"
6634          * entries to the diff-core.  They will be prefixed
6635          * with something like '=' or '*' (I haven't decided
6636          * which but should not make any difference).
6637          * Feeding the same new and old to diff_change()
6638          * also has the same effect.
6639          * Before the final output happens, they are pruned after
6640          * merged into rename/copy pairs as appropriate.
6641          */
6642         if (options->flags.reverse_diff)
6643                 addremove = (addremove == '+' ? '-' :
6644                              addremove == '-' ? '+' : addremove);
6645
6646         if (options->prefix &&
6647             strncmp(concatpath, options->prefix, options->prefix_length))
6648                 return;
6649
6650         one = alloc_filespec(concatpath);
6651         two = alloc_filespec(concatpath);
6652
6653         if (addremove != '+')
6654                 fill_filespec(one, oid, oid_valid, mode);
6655         if (addremove != '-') {
6656                 fill_filespec(two, oid, oid_valid, mode);
6657                 two->dirty_submodule = dirty_submodule;
6658         }
6659
6660         diff_queue(&diff_queued_diff, one, two);
6661         if (!options->flags.diff_from_contents)
6662                 options->flags.has_changes = 1;
6663 }
6664
6665 void diff_change(struct diff_options *options,
6666                  unsigned old_mode, unsigned new_mode,
6667                  const struct object_id *old_oid,
6668                  const struct object_id *new_oid,
6669                  int old_oid_valid, int new_oid_valid,
6670                  const char *concatpath,
6671                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
6672 {
6673         struct diff_filespec *one, *two;
6674         struct diff_filepair *p;
6675
6676         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
6677             is_submodule_ignored(concatpath, options))
6678                 return;
6679
6680         if (options->flags.reverse_diff) {
6681                 SWAP(old_mode, new_mode);
6682                 SWAP(old_oid, new_oid);
6683                 SWAP(old_oid_valid, new_oid_valid);
6684                 SWAP(old_dirty_submodule, new_dirty_submodule);
6685         }
6686
6687         if (options->prefix &&
6688             strncmp(concatpath, options->prefix, options->prefix_length))
6689                 return;
6690
6691         one = alloc_filespec(concatpath);
6692         two = alloc_filespec(concatpath);
6693         fill_filespec(one, old_oid, old_oid_valid, old_mode);
6694         fill_filespec(two, new_oid, new_oid_valid, new_mode);
6695         one->dirty_submodule = old_dirty_submodule;
6696         two->dirty_submodule = new_dirty_submodule;
6697         p = diff_queue(&diff_queued_diff, one, two);
6698
6699         if (options->flags.diff_from_contents)
6700                 return;
6701
6702         if (options->flags.quick && options->skip_stat_unmatch &&
6703             !diff_filespec_check_stat_unmatch(options->repo, p))
6704                 return;
6705
6706         options->flags.has_changes = 1;
6707 }
6708
6709 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
6710 {
6711         struct diff_filepair *pair;
6712         struct diff_filespec *one, *two;
6713
6714         if (options->prefix &&
6715             strncmp(path, options->prefix, options->prefix_length))
6716                 return NULL;
6717
6718         one = alloc_filespec(path);
6719         two = alloc_filespec(path);
6720         pair = diff_queue(&diff_queued_diff, one, two);
6721         pair->is_unmerged = 1;
6722         return pair;
6723 }
6724
6725 static char *run_textconv(struct repository *r,
6726                           const char *pgm,
6727                           struct diff_filespec *spec,
6728                           size_t *outsize)
6729 {
6730         struct diff_tempfile *temp;
6731         const char *argv[3];
6732         const char **arg = argv;
6733         struct child_process child = CHILD_PROCESS_INIT;
6734         struct strbuf buf = STRBUF_INIT;
6735         int err = 0;
6736
6737         temp = prepare_temp_file(r, spec->path, spec);
6738         *arg++ = pgm;
6739         *arg++ = temp->name;
6740         *arg = NULL;
6741
6742         child.use_shell = 1;
6743         child.argv = argv;
6744         child.out = -1;
6745         if (start_command(&child)) {
6746                 remove_tempfile();
6747                 return NULL;
6748         }
6749
6750         if (strbuf_read(&buf, child.out, 0) < 0)
6751                 err = error("error reading from textconv command '%s'", pgm);
6752         close(child.out);
6753
6754         if (finish_command(&child) || err) {
6755                 strbuf_release(&buf);
6756                 remove_tempfile();
6757                 return NULL;
6758         }
6759         remove_tempfile();
6760
6761         return strbuf_detach(&buf, outsize);
6762 }
6763
6764 size_t fill_textconv(struct repository *r,
6765                      struct userdiff_driver *driver,
6766                      struct diff_filespec *df,
6767                      char **outbuf)
6768 {
6769         size_t size;
6770
6771         if (!driver) {
6772                 if (!DIFF_FILE_VALID(df)) {
6773                         *outbuf = "";
6774                         return 0;
6775                 }
6776                 if (diff_populate_filespec(r, df, 0))
6777                         die("unable to read files to diff");
6778                 *outbuf = df->data;
6779                 return df->size;
6780         }
6781
6782         if (!driver->textconv)
6783                 BUG("fill_textconv called with non-textconv driver");
6784
6785         if (driver->textconv_cache && df->oid_valid) {
6786                 *outbuf = notes_cache_get(driver->textconv_cache,
6787                                           &df->oid,
6788                                           &size);
6789                 if (*outbuf)
6790                         return size;
6791         }
6792
6793         *outbuf = run_textconv(r, driver->textconv, df, &size);
6794         if (!*outbuf)
6795                 die("unable to read files to diff");
6796
6797         if (driver->textconv_cache && df->oid_valid) {
6798                 /* ignore errors, as we might be in a readonly repository */
6799                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6800                                 size);
6801                 /*
6802                  * we could save up changes and flush them all at the end,
6803                  * but we would need an extra call after all diffing is done.
6804                  * Since generating a cache entry is the slow path anyway,
6805                  * this extra overhead probably isn't a big deal.
6806                  */
6807                 notes_cache_write(driver->textconv_cache);
6808         }
6809
6810         return size;
6811 }
6812
6813 int textconv_object(struct repository *r,
6814                     const char *path,
6815                     unsigned mode,
6816                     const struct object_id *oid,
6817                     int oid_valid,
6818                     char **buf,
6819                     unsigned long *buf_size)
6820 {
6821         struct diff_filespec *df;
6822         struct userdiff_driver *textconv;
6823
6824         df = alloc_filespec(path);
6825         fill_filespec(df, oid, oid_valid, mode);
6826         textconv = get_textconv(r, df);
6827         if (!textconv) {
6828                 free_filespec(df);
6829                 return 0;
6830         }
6831
6832         *buf_size = fill_textconv(r, textconv, df, buf);
6833         free_filespec(df);
6834         return 1;
6835 }
6836
6837 void setup_diff_pager(struct diff_options *opt)
6838 {
6839         /*
6840          * If the user asked for our exit code, then either they want --quiet
6841          * or --exit-code. We should definitely not bother with a pager in the
6842          * former case, as we will generate no output. Since we still properly
6843          * report our exit code even when a pager is run, we _could_ run a
6844          * pager with --exit-code. But since we have not done so historically,
6845          * and because it is easy to find people oneline advising "git diff
6846          * --exit-code" in hooks and other scripts, we do not do so.
6847          */
6848         if (!opt->flags.exit_with_status &&
6849             check_pager_config("diff") != 0)
6850                 setup_pager();
6851 }