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 "help.h"
  27
  28 #ifdef NO_FAST_WORKING_DIRECTORY
  29 #define FAST_WORKING_DIRECTORY 0
  30 #else
  31 #define FAST_WORKING_DIRECTORY 1
  32 #endif
  33
  34 static int diff_detect_rename_default;
  35 static int diff_indent_heuristic = 1;
  36 static int diff_rename_limit_default = 400;
  37 static int diff_suppress_blank_empty;
  38 static int diff_use_color_default = -1;
  39 static int diff_color_moved_default;
  40 static int diff_color_moved_ws_default;
  41 static int diff_context_default = 3;
  42 static int diff_interhunk_context_default;
  43 static const char *diff_word_regex_cfg;
  44 static const char *external_diff_cmd_cfg;
  45 static const char *diff_order_file_cfg;
  46 int diff_auto_refresh_index = 1;
  47 static int diff_mnemonic_prefix;
  48 static int diff_no_prefix;
  49 static int diff_stat_graph_width;
  50 static int diff_dirstat_permille_default = 30;
  51 static struct diff_options default_diff_options;
  52 static long diff_algorithm;
  53 static unsigned ws_error_highlight_default = WSEH_NEW;
  54
  55 static char diff_colors[][COLOR_MAXLEN] = {
  56         GIT_COLOR_RESET,
  57         GIT_COLOR_NORMAL,       /* CONTEXT */
  58         GIT_COLOR_BOLD,         /* METAINFO */
  59         GIT_COLOR_CYAN,         /* FRAGINFO */
  60         GIT_COLOR_RED,          /* OLD */
  61         GIT_COLOR_GREEN,        /* NEW */
  62         GIT_COLOR_YELLOW,       /* COMMIT */
  63         GIT_COLOR_BG_RED,       /* WHITESPACE */
  64         GIT_COLOR_NORMAL,       /* FUNCINFO */
  65         GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  66         GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  67         GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  68         GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  69         GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  70         GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  71         GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  72         GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  73         GIT_COLOR_FAINT,        /* CONTEXT_DIM */
  74         GIT_COLOR_FAINT_RED,    /* OLD_DIM */
  75         GIT_COLOR_FAINT_GREEN,  /* NEW_DIM */
  76         GIT_COLOR_BOLD,         /* CONTEXT_BOLD */
  77         GIT_COLOR_BOLD_RED,     /* OLD_BOLD */
  78         GIT_COLOR_BOLD_GREEN,   /* NEW_BOLD */
  79 };
  80
  81 static const char *color_diff_slots[] = {
  82         [DIFF_CONTEXT]                = "context",
  83         [DIFF_METAINFO]               = "meta",
  84         [DIFF_FRAGINFO]               = "frag",
  85         [DIFF_FILE_OLD]               = "old",
  86         [DIFF_FILE_NEW]               = "new",
  87         [DIFF_COMMIT]                 = "commit",
  88         [DIFF_WHITESPACE]             = "whitespace",
  89         [DIFF_FUNCINFO]               = "func",
  90         [DIFF_FILE_OLD_MOVED]         = "oldMoved",
  91         [DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
  92         [DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
  93         [DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
  94         [DIFF_FILE_NEW_MOVED]         = "newMoved",
  95         [DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
  96         [DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
  97         [DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
  98         [DIFF_CONTEXT_DIM]            = "contextDimmed",
  99         [DIFF_FILE_OLD_DIM]           = "oldDimmed",
 100         [DIFF_FILE_NEW_DIM]           = "newDimmed",
 101         [DIFF_CONTEXT_BOLD]           = "contextBold",
 102         [DIFF_FILE_OLD_BOLD]          = "oldBold",
 103         [DIFF_FILE_NEW_BOLD]          = "newBold",
 104 };
 105
 106 static NORETURN void die_want_option(const char *option_name)
 107 {
 108         die(_("option '%s' requires a value"), option_name);
 109 }
 110
 111 define_list_config_array_extra(color_diff_slots, {"plain"});
 112
 113 static int parse_diff_color_slot(const char *var)
 114 {
 115         if (!strcasecmp(var, "plain"))
 116                 return DIFF_CONTEXT;
 117         return LOOKUP_CONFIG(color_diff_slots, var);
 118 }
 119
 120 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 121                                 struct strbuf *errmsg)
 122 {
 123         char *params_copy = xstrdup(params_string);
 124         struct string_list params = STRING_LIST_INIT_NODUP;
 125         int ret = 0;
 126         int i;
 127
 128         if (*params_copy)
 129                 string_list_split_in_place(&params, params_copy, ',', -1);
 130         for (i = 0; i < params.nr; i++) {
 131                 const char *p = params.items[i].string;
 132                 if (!strcmp(p, "changes")) {
 133                         options->flags.dirstat_by_line = 0;
 134                         options->flags.dirstat_by_file = 0;
 135                 } else if (!strcmp(p, "lines")) {
 136                         options->flags.dirstat_by_line = 1;
 137                         options->flags.dirstat_by_file = 0;
 138                 } else if (!strcmp(p, "files")) {
 139                         options->flags.dirstat_by_line = 0;
 140                         options->flags.dirstat_by_file = 1;
 141                 } else if (!strcmp(p, "noncumulative")) {
 142                         options->flags.dirstat_cumulative = 0;
 143                 } else if (!strcmp(p, "cumulative")) {
 144                         options->flags.dirstat_cumulative = 1;
 145                 } else if (isdigit(*p)) {
 146                         char *end;
 147                         int permille = strtoul(p, &end, 10) * 10;
 148                         if (*end == '.' && isdigit(*++end)) {
 149                                 /* only use first digit */
 150                                 permille += *end - '0';
 151                                 /* .. and ignore any further digits */
 152                                 while (isdigit(*++end))
 153                                         ; /* nothing */
 154                         }
 155                         if (!*end)
 156                                 options->dirstat_permille = permille;
 157                         else {
 158                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 159                                             p);
 160                                 ret++;
 161                         }
 162                 } else {
 163                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 164                         ret++;
 165                 }
 166
 167         }
 168         string_list_clear(&params, 0);
 169         free(params_copy);
 170         return ret;
 171 }
 172
 173 static int parse_submodule_params(struct diff_options *options, const char *value)
 174 {
 175         if (!strcmp(value, "log"))
 176                 options->submodule_format = DIFF_SUBMODULE_LOG;
 177         else if (!strcmp(value, "short"))
 178                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 179         else if (!strcmp(value, "diff"))
 180                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 181         else
 182                 return -1;
 183         return 0;
 184 }
 185
 186 int git_config_rename(const char *var, const char *value)
 187 {
 188         if (!value)
 189                 return DIFF_DETECT_RENAME;
 190         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 191                 return  DIFF_DETECT_COPY;
 192         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 193 }
 194
 195 long parse_algorithm_value(const char *value)
 196 {
 197         if (!value)
 198                 return -1;
 199         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 200                 return 0;
 201         else if (!strcasecmp(value, "minimal"))
 202                 return XDF_NEED_MINIMAL;
 203         else if (!strcasecmp(value, "patience"))
 204                 return XDF_PATIENCE_DIFF;
 205         else if (!strcasecmp(value, "histogram"))
 206                 return XDF_HISTOGRAM_DIFF;
 207         return -1;
 208 }
 209
 210 static int parse_one_token(const char **arg, const char *token)
 211 {
 212         const char *rest;
 213         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 214                 *arg = rest;
 215                 return 1;
 216         }
 217         return 0;
 218 }
 219
 220 static int parse_ws_error_highlight(const char *arg)
 221 {
 222         const char *orig_arg = arg;
 223         unsigned val = 0;
 224
 225         while (*arg) {
 226                 if (parse_one_token(&arg, "none"))
 227                         val = 0;
 228                 else if (parse_one_token(&arg, "default"))
 229                         val = WSEH_NEW;
 230                 else if (parse_one_token(&arg, "all"))
 231                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 232                 else if (parse_one_token(&arg, "new"))
 233                         val |= WSEH_NEW;
 234                 else if (parse_one_token(&arg, "old"))
 235                         val |= WSEH_OLD;
 236                 else if (parse_one_token(&arg, "context"))
 237                         val |= WSEH_CONTEXT;
 238                 else {
 239                         return -1 - (int)(arg - orig_arg);
 240                 }
 241                 if (*arg)
 242                         arg++;
 243         }
 244         return val;
 245 }
 246
 247 /*
 248  * These are to give UI layer defaults.
 249  * The core-level commands such as git-diff-files should
 250  * never be affected by the setting of diff.renames
 251  * the user happens to have in the configuration file.
 252  */
 253 void init_diff_ui_defaults(void)
 254 {
 255         diff_detect_rename_default = DIFF_DETECT_RENAME;
 256 }
 257
 258 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 259 {
 260         if (!strcmp(var, "diff.indentheuristic"))
 261                 diff_indent_heuristic = git_config_bool(var, value);
 262         return 0;
 263 }
 264
 265 static int parse_color_moved(const char *arg)
 266 {
 267         switch (git_parse_maybe_bool(arg)) {
 268         case 0:
 269                 return COLOR_MOVED_NO;
 270         case 1:
 271                 return COLOR_MOVED_DEFAULT;
 272         default:
 273                 break;
 274         }
 275
 276         if (!strcmp(arg, "no"))
 277                 return COLOR_MOVED_NO;
 278         else if (!strcmp(arg, "plain"))
 279                 return COLOR_MOVED_PLAIN;
 280         else if (!strcmp(arg, "blocks"))
 281                 return COLOR_MOVED_BLOCKS;
 282         else if (!strcmp(arg, "zebra"))
 283                 return COLOR_MOVED_ZEBRA;
 284         else if (!strcmp(arg, "default"))
 285                 return COLOR_MOVED_DEFAULT;
 286         else if (!strcmp(arg, "dimmed-zebra"))
 287                 return COLOR_MOVED_ZEBRA_DIM;
 288         else if (!strcmp(arg, "dimmed_zebra"))
 289                 return COLOR_MOVED_ZEBRA_DIM;
 290         else
 291                 return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed-zebra', 'plain'"));
 292 }
 293
 294 static int parse_color_moved_ws(const char *arg)
 295 {
 296         int ret = 0;
 297         struct string_list l = STRING_LIST_INIT_DUP;
 298         struct string_list_item *i;
 299
 300         string_list_split(&l, arg, ',', -1);
 301
 302         for_each_string_list_item(i, &l) {
 303                 struct strbuf sb = STRBUF_INIT;
 304                 strbuf_addstr(&sb, i->string);
 305                 strbuf_trim(&sb);
 306
 307                 if (!strcmp(sb.buf, "ignore-space-change"))
 308                         ret |= XDF_IGNORE_WHITESPACE_CHANGE;
 309                 else if (!strcmp(sb.buf, "ignore-space-at-eol"))
 310                         ret |= XDF_IGNORE_WHITESPACE_AT_EOL;
 311                 else if (!strcmp(sb.buf, "ignore-all-space"))
 312                         ret |= XDF_IGNORE_WHITESPACE;
 313                 else if (!strcmp(sb.buf, "allow-indentation-change"))
 314                         ret |= COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE;
 315                 else
 316                         error(_("ignoring unknown color-moved-ws mode '%s'"), sb.buf);
 317
 318                 strbuf_release(&sb);
 319         }
 320
 321         if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
 322             (ret & XDF_WHITESPACE_FLAGS))
 323                 die(_("color-moved-ws: allow-indentation-change cannot be combined with other white space modes"));
 324
 325         string_list_clear(&l, 0);
 326
 327         return ret;
 328 }
 329
 330 int git_diff_ui_config(const char *var, const char *value, void *cb)
 331 {
 332         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 333                 diff_use_color_default = git_config_colorbool(var, value);
 334                 return 0;
 335         }
 336         if (!strcmp(var, "diff.colormoved")) {
 337                 int cm = parse_color_moved(value);
 338                 if (cm < 0)
 339                         return -1;
 340                 diff_color_moved_default = cm;
 341                 return 0;
 342         }
 343         if (!strcmp(var, "diff.colormovedws")) {
 344                 int cm = parse_color_moved_ws(value);
 345                 if (cm < 0)
 346                         return -1;
 347                 diff_color_moved_ws_default = cm;
 348                 return 0;
 349         }
 350         if (!strcmp(var, "diff.context")) {
 351                 diff_context_default = git_config_int(var, value);
 352                 if (diff_context_default < 0)
 353                         return -1;
 354                 return 0;
 355         }
 356         if (!strcmp(var, "diff.interhunkcontext")) {
 357                 diff_interhunk_context_default = git_config_int(var, value);
 358                 if (diff_interhunk_context_default < 0)
 359                         return -1;
 360                 return 0;
 361         }
 362         if (!strcmp(var, "diff.renames")) {
 363                 diff_detect_rename_default = git_config_rename(var, value);
 364                 return 0;
 365         }
 366         if (!strcmp(var, "diff.autorefreshindex")) {
 367                 diff_auto_refresh_index = git_config_bool(var, value);
 368                 return 0;
 369         }
 370         if (!strcmp(var, "diff.mnemonicprefix")) {
 371                 diff_mnemonic_prefix = git_config_bool(var, value);
 372                 return 0;
 373         }
 374         if (!strcmp(var, "diff.noprefix")) {
 375                 diff_no_prefix = git_config_bool(var, value);
 376                 return 0;
 377         }
 378         if (!strcmp(var, "diff.statgraphwidth")) {
 379                 diff_stat_graph_width = git_config_int(var, value);
 380                 return 0;
 381         }
 382         if (!strcmp(var, "diff.external"))
 383                 return git_config_string(&external_diff_cmd_cfg, var, value);
 384         if (!strcmp(var, "diff.wordregex"))
 385                 return git_config_string(&diff_word_regex_cfg, var, value);
 386         if (!strcmp(var, "diff.orderfile"))
 387                 return git_config_pathname(&diff_order_file_cfg, var, value);
 388
 389         if (!strcmp(var, "diff.ignoresubmodules"))
 390                 handle_ignore_submodules_arg(&default_diff_options, value);
 391
 392         if (!strcmp(var, "diff.submodule")) {
 393                 if (parse_submodule_params(&default_diff_options, value))
 394                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 395                                 value);
 396                 return 0;
 397         }
 398
 399         if (!strcmp(var, "diff.algorithm")) {
 400                 diff_algorithm = parse_algorithm_value(value);
 401                 if (diff_algorithm < 0)
 402                         return -1;
 403                 return 0;
 404         }
 405
 406         if (!strcmp(var, "diff.wserrorhighlight")) {
 407                 int val = parse_ws_error_highlight(value);
 408                 if (val < 0)
 409                         return -1;
 410                 ws_error_highlight_default = val;
 411                 return 0;
 412         }
 413
 414         if (git_color_config(var, value, cb) < 0)
 415                 return -1;
 416
 417         return git_diff_basic_config(var, value, cb);
 418 }
 419
 420 int git_diff_basic_config(const char *var, const char *value, void *cb)
 421 {
 422         const char *name;
 423
 424         if (!strcmp(var, "diff.renamelimit")) {
 425                 diff_rename_limit_default = git_config_int(var, value);
 426                 return 0;
 427         }
 428
 429         if (userdiff_config(var, value) < 0)
 430                 return -1;
 431
 432         if (skip_prefix(var, "diff.color.", &name) ||
 433             skip_prefix(var, "color.diff.", &name)) {
 434                 int slot = parse_diff_color_slot(name);
 435                 if (slot < 0)
 436                         return 0;
 437                 if (!value)
 438                         return config_error_nonbool(var);
 439                 return color_parse(value, diff_colors[slot]);
 440         }
 441
 442         /* like GNU diff's --suppress-blank-empty option  */
 443         if (!strcmp(var, "diff.suppressblankempty") ||
 444                         /* for backwards compatibility */
 445                         !strcmp(var, "diff.suppress-blank-empty")) {
 446                 diff_suppress_blank_empty = git_config_bool(var, value);
 447                 return 0;
 448         }
 449
 450         if (!strcmp(var, "diff.dirstat")) {
 451                 struct strbuf errmsg = STRBUF_INIT;
 452                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 453                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 454                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 455                                 errmsg.buf);
 456                 strbuf_release(&errmsg);
 457                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 458                 return 0;
 459         }
 460
 461         if (git_diff_heuristic_config(var, value, cb) < 0)
 462                 return -1;
 463
 464         return git_default_config(var, value, cb);
 465 }
 466
 467 static char *quote_two(const char *one, const char *two)
 468 {
 469         int need_one = quote_c_style(one, NULL, NULL, 1);
 470         int need_two = quote_c_style(two, NULL, NULL, 1);
 471         struct strbuf res = STRBUF_INIT;
 472
 473         if (need_one + need_two) {
 474                 strbuf_addch(&res, '"');
 475                 quote_c_style(one, &res, NULL, 1);
 476                 quote_c_style(two, &res, NULL, 1);
 477                 strbuf_addch(&res, '"');
 478         } else {
 479                 strbuf_addstr(&res, one);
 480                 strbuf_addstr(&res, two);
 481         }
 482         return strbuf_detach(&res, NULL);
 483 }
 484
 485 static const char *external_diff(void)
 486 {
 487         static const char *external_diff_cmd = NULL;
 488         static int done_preparing = 0;
 489
 490         if (done_preparing)
 491                 return external_diff_cmd;
 492         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 493         if (!external_diff_cmd)
 494                 external_diff_cmd = external_diff_cmd_cfg;
 495         done_preparing = 1;
 496         return external_diff_cmd;
 497 }
 498
 499 /*
 500  * Keep track of files used for diffing. Sometimes such an entry
 501  * refers to a temporary file, sometimes to an existing file, and
 502  * sometimes to "/dev/null".
 503  */
 504 static struct diff_tempfile {
 505         /*
 506          * filename external diff should read from, or NULL if this
 507          * entry is currently not in use:
 508          */
 509         const char *name;
 510
 511         char hex[GIT_MAX_HEXSZ + 1];
 512         char mode[10];
 513
 514         /*
 515          * If this diff_tempfile instance refers to a temporary file,
 516          * this tempfile object is used to manage its lifetime.
 517          */
 518         struct tempfile *tempfile;
 519 } diff_temp[2];
 520
 521 struct emit_callback {
 522         int color_diff;
 523         unsigned ws_rule;
 524         int blank_at_eof_in_preimage;
 525         int blank_at_eof_in_postimage;
 526         int lno_in_preimage;
 527         int lno_in_postimage;
 528         const char **label_path;
 529         struct diff_words_data *diff_words;
 530         struct diff_options *opt;
 531         struct strbuf *header;
 532 };
 533
 534 static int count_lines(const char *data, int size)
 535 {
 536         int count, ch, completely_empty = 1, nl_just_seen = 0;
 537         count = 0;
 538         while (0 < size--) {
 539                 ch = *data++;
 540                 if (ch == '\n') {
 541                         count++;
 542                         nl_just_seen = 1;
 543                         completely_empty = 0;
 544                 }
 545                 else {
 546                         nl_just_seen = 0;
 547                         completely_empty = 0;
 548                 }
 549         }
 550         if (completely_empty)
 551                 return 0;
 552         if (!nl_just_seen)
 553                 count++; /* no trailing newline */
 554         return count;
 555 }
 556
 557 static int fill_mmfile(struct repository *r, mmfile_t *mf,
 558                        struct diff_filespec *one)
 559 {
 560         if (!DIFF_FILE_VALID(one)) {
 561                 mf->ptr = (char *)""; /* does not matter */
 562                 mf->size = 0;
 563                 return 0;
 564         }
 565         else if (diff_populate_filespec(r, one, 0))
 566                 return -1;
 567
 568         mf->ptr = one->data;
 569         mf->size = one->size;
 570         return 0;
 571 }
 572
 573 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 574 static unsigned long diff_filespec_size(struct repository *r,
 575                                         struct diff_filespec *one)
 576 {
 577         if (!DIFF_FILE_VALID(one))
 578                 return 0;
 579         diff_populate_filespec(r, one, CHECK_SIZE_ONLY);
 580         return one->size;
 581 }
 582
 583 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 584 {
 585         char *ptr = mf->ptr;
 586         long size = mf->size;
 587         int cnt = 0;
 588
 589         if (!size)
 590                 return cnt;
 591         ptr += size - 1; /* pointing at the very end */
 592         if (*ptr != '\n')
 593                 ; /* incomplete line */
 594         else
 595                 ptr--; /* skip the last LF */
 596         while (mf->ptr < ptr) {
 597                 char *prev_eol;
 598                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 599                         if (*prev_eol == '\n')
 600                                 break;
 601                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 602                         break;
 603                 cnt++;
 604                 ptr = prev_eol - 1;
 605         }
 606         return cnt;
 607 }
 608
 609 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 610                                struct emit_callback *ecbdata)
 611 {
 612         int l1, l2, at;
 613         unsigned ws_rule = ecbdata->ws_rule;
 614         l1 = count_trailing_blank(mf1, ws_rule);
 615         l2 = count_trailing_blank(mf2, ws_rule);
 616         if (l2 <= l1) {
 617                 ecbdata->blank_at_eof_in_preimage = 0;
 618                 ecbdata->blank_at_eof_in_postimage = 0;
 619                 return;
 620         }
 621         at = count_lines(mf1->ptr, mf1->size);
 622         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 623
 624         at = count_lines(mf2->ptr, mf2->size);
 625         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 626 }
 627
 628 static void emit_line_0(struct diff_options *o,
 629                         const char *set_sign, const char *set, unsigned reverse, const char *reset,
 630                         int first, const char *line, int len)
 631 {
 632         int has_trailing_newline, has_trailing_carriage_return;
 633         int needs_reset = 0; /* at the end of the line */
 634         FILE *file = o->file;
 635
 636         fputs(diff_line_prefix(o), file);
 637
 638         has_trailing_newline = (len > 0 && line[len-1] == '\n');
 639         if (has_trailing_newline)
 640                 len--;
 641
 642         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 643         if (has_trailing_carriage_return)
 644                 len--;
 645
 646         if (!len && !first)
 647                 goto end_of_line;
 648
 649         if (reverse && want_color(o->use_color)) {
 650                 fputs(GIT_COLOR_REVERSE, file);
 651                 needs_reset = 1;
 652         }
 653
 654         if (set_sign) {
 655                 fputs(set_sign, file);
 656                 needs_reset = 1;
 657         }
 658
 659         if (first)
 660                 fputc(first, file);
 661
 662         if (!len)
 663                 goto end_of_line;
 664
 665         if (set) {
 666                 if (set_sign && set != set_sign)
 667                         fputs(reset, file);
 668                 fputs(set, file);
 669                 needs_reset = 1;
 670         }
 671         fwrite(line, len, 1, file);
 672         needs_reset = 1; /* 'line' may contain color codes. */
 673
 674 end_of_line:
 675         if (needs_reset)
 676                 fputs(reset, file);
 677         if (has_trailing_carriage_return)
 678                 fputc('\r', file);
 679         if (has_trailing_newline)
 680                 fputc('\n', file);
 681 }
 682
 683 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 684                       const char *line, int len)
 685 {
 686         emit_line_0(o, set, NULL, 0, reset, 0, line, len);
 687 }
 688
 689 enum diff_symbol {
 690         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 691         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 692         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 693         DIFF_SYMBOL_BINARY_DIFF_BODY,
 694         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 695         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 696         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 697         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 698         DIFF_SYMBOL_STATS_LINE,
 699         DIFF_SYMBOL_WORD_DIFF,
 700         DIFF_SYMBOL_STAT_SEP,
 701         DIFF_SYMBOL_SUMMARY,
 702         DIFF_SYMBOL_SUBMODULE_ADD,
 703         DIFF_SYMBOL_SUBMODULE_DEL,
 704         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 705         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 706         DIFF_SYMBOL_SUBMODULE_HEADER,
 707         DIFF_SYMBOL_SUBMODULE_ERROR,
 708         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 709         DIFF_SYMBOL_REWRITE_DIFF,
 710         DIFF_SYMBOL_BINARY_FILES,
 711         DIFF_SYMBOL_HEADER,
 712         DIFF_SYMBOL_FILEPAIR_PLUS,
 713         DIFF_SYMBOL_FILEPAIR_MINUS,
 714         DIFF_SYMBOL_WORDS_PORCELAIN,
 715         DIFF_SYMBOL_WORDS,
 716         DIFF_SYMBOL_CONTEXT,
 717         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 718         DIFF_SYMBOL_PLUS,
 719         DIFF_SYMBOL_MINUS,
 720         DIFF_SYMBOL_NO_LF_EOF,
 721         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 722         DIFF_SYMBOL_CONTEXT_MARKER,
 723         DIFF_SYMBOL_SEPARATOR
 724 };
 725 /*
 726  * Flags for content lines:
 727  * 0..12 are whitespace rules
 728  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 729  * 16 is marking if the line is blank at EOF
 730  */
 731 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 732 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 733 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 734 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 735 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 736
 737 /*
 738  * This struct is used when we need to buffer the output of the diff output.
 739  *
 740  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 741  * into the pre/post image file. This pointer could be a union with the
 742  * line pointer. By storing an offset into the file instead of the literal line,
 743  * we can decrease the memory footprint for the buffered output. At first we
 744  * may want to only have indirection for the content lines, but we could also
 745  * enhance the state for emitting prefabricated lines, e.g. the similarity
 746  * score line or hunk/file headers would only need to store a number or path
 747  * and then the output can be constructed later on depending on state.
 748  */
 749 struct emitted_diff_symbol {
 750         const char *line;
 751         int len;
 752         int flags;
 753         enum diff_symbol s;
 754 };
 755 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 756
 757 struct emitted_diff_symbols {
 758         struct emitted_diff_symbol *buf;
 759         int nr, alloc;
 760 };
 761 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 762
 763 static void append_emitted_diff_symbol(struct diff_options *o,
 764                                        struct emitted_diff_symbol *e)
 765 {
 766         struct emitted_diff_symbol *f;
 767
 768         ALLOC_GROW(o->emitted_symbols->buf,
 769                    o->emitted_symbols->nr + 1,
 770                    o->emitted_symbols->alloc);
 771         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 772
 773         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 774         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 775 }
 776
 777 struct moved_entry {
 778         struct hashmap_entry ent;
 779         const struct emitted_diff_symbol *es;
 780         struct moved_entry *next_line;
 781 };
 782
 783 /**
 784  * The struct ws_delta holds white space differences between moved lines, i.e.
 785  * between '+' and '-' lines that have been detected to be a move.
 786  * The string contains the difference in leading white spaces, before the
 787  * rest of the line is compared using the white space config for move
 788  * coloring. The current_longer indicates if the first string in the
 789  * comparision is longer than the second.
 790  */
 791 struct ws_delta {
 792         char *string;
 793         unsigned int current_longer : 1;
 794 };
 795 #define WS_DELTA_INIT { NULL, 0 }
 796
 797 struct moved_block {
 798         struct moved_entry *match;
 799         struct ws_delta wsd;
 800 };
 801
 802 static void moved_block_clear(struct moved_block *b)
 803 {
 804         FREE_AND_NULL(b->wsd.string);
 805         b->match = NULL;
 806 }
 807
 808 static int compute_ws_delta(const struct emitted_diff_symbol *a,
 809                              const struct emitted_diff_symbol *b,
 810                              struct ws_delta *out)
 811 {
 812         const struct emitted_diff_symbol *longer =  a->len > b->len ? a : b;
 813         const struct emitted_diff_symbol *shorter = a->len > b->len ? b : a;
 814         int d = longer->len - shorter->len;
 815
 816         if (strncmp(longer->line + d, shorter->line, shorter->len))
 817                 return 0;
 818
 819         out->string = xmemdupz(longer->line, d);
 820         out->current_longer = (a == longer);
 821
 822         return 1;
 823 }
 824
 825 static int cmp_in_block_with_wsd(const struct diff_options *o,
 826                                  const struct moved_entry *cur,
 827                                  const struct moved_entry *match,
 828                                  struct moved_block *pmb,
 829                                  int n)
 830 {
 831         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 832         int al = cur->es->len, cl = l->len;
 833         const char *a = cur->es->line,
 834                    *b = match->es->line,
 835                    *c = l->line;
 836
 837         int wslen;
 838
 839         /*
 840          * We need to check if 'cur' is equal to 'match'.
 841          * As those are from the same (+/-) side, we do not need to adjust for
 842          * indent changes. However these were found using fuzzy matching
 843          * so we do have to check if they are equal.
 844          */
 845         if (strcmp(a, b))
 846                 return 1;
 847
 848         if (!pmb->wsd.string)
 849                 /*
 850                  * The white space delta is not active? This can happen
 851                  * when we exit early in this function.
 852                  */
 853                 return 1;
 854
 855         /*
 856          * The indent changes of the block are known and stored in
 857          * pmb->wsd; however we need to check if the indent changes of the
 858          * current line are still the same as before.
 859          *
 860          * To do so we need to compare 'l' to 'cur', adjusting the
 861          * one of them for the white spaces, depending which was longer.
 862          */
 863
 864         wslen = strlen(pmb->wsd.string);
 865         if (pmb->wsd.current_longer) {
 866                 c += wslen;
 867                 cl -= wslen;
 868         } else {
 869                 a += wslen;
 870                 al -= wslen;
 871         }
 872
 873         if (al != cl || memcmp(a, c, al))
 874                 return 1;
 875
 876         return 0;
 877 }
 878
 879 static int moved_entry_cmp(const void *hashmap_cmp_fn_data,
 880                            const void *entry,
 881                            const void *entry_or_key,
 882                            const void *keydata)
 883 {
 884         const struct diff_options *diffopt = hashmap_cmp_fn_data;
 885         const struct moved_entry *a = entry;
 886         const struct moved_entry *b = entry_or_key;
 887         unsigned flags = diffopt->color_moved_ws_handling
 888                          & XDF_WHITESPACE_FLAGS;
 889
 890         if (diffopt->color_moved_ws_handling &
 891             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
 892                 /*
 893                  * As there is not specific white space config given,
 894                  * we'd need to check for a new block, so ignore all
 895                  * white space. The setup of the white space
 896                  * configuration for the next block is done else where
 897                  */
 898                 flags |= XDF_IGNORE_WHITESPACE;
 899
 900         return !xdiff_compare_lines(a->es->line, a->es->len,
 901                                     b->es->line, b->es->len,
 902                                     flags);
 903 }
 904
 905 static struct moved_entry *prepare_entry(struct diff_options *o,
 906                                          int line_no)
 907 {
 908         struct moved_entry *ret = xmalloc(sizeof(*ret));
 909         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 910         unsigned flags = o->color_moved_ws_handling & XDF_WHITESPACE_FLAGS;
 911
 912         ret->ent.hash = xdiff_hash_string(l->line, l->len, flags);
 913         ret->es = l;
 914         ret->next_line = NULL;
 915
 916         return ret;
 917 }
 918
 919 static void add_lines_to_move_detection(struct diff_options *o,
 920                                         struct hashmap *add_lines,
 921                                         struct hashmap *del_lines)
 922 {
 923         struct moved_entry *prev_line = NULL;
 924
 925         int n;
 926         for (n = 0; n < o->emitted_symbols->nr; n++) {
 927                 struct hashmap *hm;
 928                 struct moved_entry *key;
 929
 930                 switch (o->emitted_symbols->buf[n].s) {
 931                 case DIFF_SYMBOL_PLUS:
 932                         hm = add_lines;
 933                         break;
 934                 case DIFF_SYMBOL_MINUS:
 935                         hm = del_lines;
 936                         break;
 937                 default:
 938                         prev_line = NULL;
 939                         continue;
 940                 }
 941
 942                 key = prepare_entry(o, n);
 943                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 944                         prev_line->next_line = key;
 945
 946                 hashmap_add(hm, key);
 947                 prev_line = key;
 948         }
 949 }
 950
 951 static void pmb_advance_or_null(struct diff_options *o,
 952                                 struct moved_entry *match,
 953                                 struct hashmap *hm,
 954                                 struct moved_block *pmb,
 955                                 int pmb_nr)
 956 {
 957         int i;
 958         for (i = 0; i < pmb_nr; i++) {
 959                 struct moved_entry *prev = pmb[i].match;
 960                 struct moved_entry *cur = (prev && prev->next_line) ?
 961                                 prev->next_line : NULL;
 962                 if (cur && !hm->cmpfn(o, cur, match, NULL)) {
 963                         pmb[i].match = cur;
 964                 } else {
 965                         pmb[i].match = NULL;
 966                 }
 967         }
 968 }
 969
 970 static void pmb_advance_or_null_multi_match(struct diff_options *o,
 971                                             struct moved_entry *match,
 972                                             struct hashmap *hm,
 973                                             struct moved_block *pmb,
 974                                             int pmb_nr, int n)
 975 {
 976         int i;
 977         char *got_match = xcalloc(1, pmb_nr);
 978
 979         for (; match; match = hashmap_get_next(hm, match)) {
 980                 for (i = 0; i < pmb_nr; i++) {
 981                         struct moved_entry *prev = pmb[i].match;
 982                         struct moved_entry *cur = (prev && prev->next_line) ?
 983                                         prev->next_line : NULL;
 984                         if (!cur)
 985                                 continue;
 986                         if (!cmp_in_block_with_wsd(o, cur, match, &pmb[i], n))
 987                                 got_match[i] |= 1;
 988                 }
 989         }
 990
 991         for (i = 0; i < pmb_nr; i++) {
 992                 if (got_match[i]) {
 993                         /* Advance to the next line */
 994                         pmb[i].match = pmb[i].match->next_line;
 995                 } else {
 996                         moved_block_clear(&pmb[i]);
 997                 }
 998         }
 999
1000         free(got_match);
1001 }
1002
1003 static int shrink_potential_moved_blocks(struct moved_block *pmb,
1004                                          int pmb_nr)
1005 {
1006         int lp, rp;
1007
1008         /* Shrink the set of potential block to the remaining running */
1009         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
1010                 while (lp < pmb_nr && pmb[lp].match)
1011                         lp++;
1012                 /* lp points at the first NULL now */
1013
1014                 while (rp > -1 && !pmb[rp].match)
1015                         rp--;
1016                 /* rp points at the last non-NULL */
1017
1018                 if (lp < pmb_nr && rp > -1 && lp < rp) {
1019                         pmb[lp] = pmb[rp];
1020                         pmb[rp].match = NULL;
1021                         pmb[rp].wsd.string = NULL;
1022                         rp--;
1023                         lp++;
1024                 }
1025         }
1026
1027         /* Remember the number of running sets */
1028         return rp + 1;
1029 }
1030
1031 /*
1032  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
1033  *
1034  * Otherwise, if the last block has fewer alphanumeric characters than
1035  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
1036  * that block.
1037  *
1038  * The last block consists of the (n - block_length)'th line up to but not
1039  * including the nth line.
1040  *
1041  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
1042  * Think of a way to unify them.
1043  */
1044 static void adjust_last_block(struct diff_options *o, int n, int block_length)
1045 {
1046         int i, alnum_count = 0;
1047         if (o->color_moved == COLOR_MOVED_PLAIN)
1048                 return;
1049         for (i = 1; i < block_length + 1; i++) {
1050                 const char *c = o->emitted_symbols->buf[n - i].line;
1051                 for (; *c; c++) {
1052                         if (!isalnum(*c))
1053                                 continue;
1054                         alnum_count++;
1055                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
1056                                 return;
1057                 }
1058         }
1059         for (i = 1; i < block_length + 1; i++)
1060                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
1061 }
1062
1063 /* Find blocks of moved code, delegate actual coloring decision to helper */
1064 static void mark_color_as_moved(struct diff_options *o,
1065                                 struct hashmap *add_lines,
1066                                 struct hashmap *del_lines)
1067 {
1068         struct moved_block *pmb = NULL; /* potentially moved blocks */
1069         int pmb_nr = 0, pmb_alloc = 0;
1070         int n, flipped_block = 1, block_length = 0;
1071
1072
1073         for (n = 0; n < o->emitted_symbols->nr; n++) {
1074                 struct hashmap *hm = NULL;
1075                 struct moved_entry *key;
1076                 struct moved_entry *match = NULL;
1077                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1078
1079                 switch (l->s) {
1080                 case DIFF_SYMBOL_PLUS:
1081                         hm = del_lines;
1082                         key = prepare_entry(o, n);
1083                         match = hashmap_get(hm, key, NULL);
1084                         free(key);
1085                         break;
1086                 case DIFF_SYMBOL_MINUS:
1087                         hm = add_lines;
1088                         key = prepare_entry(o, n);
1089                         match = hashmap_get(hm, key, NULL);
1090                         free(key);
1091                         break;
1092                 default:
1093                         flipped_block = 1;
1094                 }
1095
1096                 if (!match) {
1097                         int i;
1098
1099                         adjust_last_block(o, n, block_length);
1100                         for(i = 0; i < pmb_nr; i++)
1101                                 moved_block_clear(&pmb[i]);
1102                         pmb_nr = 0;
1103                         block_length = 0;
1104                         continue;
1105                 }
1106
1107                 l->flags |= DIFF_SYMBOL_MOVED_LINE;
1108
1109                 if (o->color_moved == COLOR_MOVED_PLAIN)
1110                         continue;
1111
1112                 if (o->color_moved_ws_handling &
1113                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
1114                         pmb_advance_or_null_multi_match(o, match, hm, pmb, pmb_nr, n);
1115                 else
1116                         pmb_advance_or_null(o, match, hm, pmb, pmb_nr);
1117
1118                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
1119
1120                 if (pmb_nr == 0) {
1121                         /*
1122                          * The current line is the start of a new block.
1123                          * Setup the set of potential blocks.
1124                          */
1125                         for (; match; match = hashmap_get_next(hm, match)) {
1126                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
1127                                 if (o->color_moved_ws_handling &
1128                                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) {
1129                                         if (compute_ws_delta(l, match->es,
1130                                                              &pmb[pmb_nr].wsd))
1131                                                 pmb[pmb_nr++].match = match;
1132                                 } else {
1133                                         pmb[pmb_nr].wsd.string = NULL;
1134                                         pmb[pmb_nr++].match = match;
1135                                 }
1136                         }
1137
1138                         flipped_block = (flipped_block + 1) % 2;
1139
1140                         adjust_last_block(o, n, block_length);
1141                         block_length = 0;
1142                 }
1143
1144                 block_length++;
1145
1146                 if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
1147                         l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
1148         }
1149         adjust_last_block(o, n, block_length);
1150
1151         for(n = 0; n < pmb_nr; n++)
1152                 moved_block_clear(&pmb[n]);
1153         free(pmb);
1154 }
1155
1156 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
1157   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
1158 static void dim_moved_lines(struct diff_options *o)
1159 {
1160         int n;
1161         for (n = 0; n < o->emitted_symbols->nr; n++) {
1162                 struct emitted_diff_symbol *prev = (n != 0) ?
1163                                 &o->emitted_symbols->buf[n - 1] : NULL;
1164                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1165                 struct emitted_diff_symbol *next =
1166                                 (n < o->emitted_symbols->nr - 1) ?
1167                                 &o->emitted_symbols->buf[n + 1] : NULL;
1168
1169                 /* Not a plus or minus line? */
1170                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
1171                         continue;
1172
1173                 /* Not a moved line? */
1174                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
1175                         continue;
1176
1177                 /*
1178                  * If prev or next are not a plus or minus line,
1179                  * pretend they don't exist
1180                  */
1181                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
1182                             prev->s != DIFF_SYMBOL_MINUS)
1183                         prev = NULL;
1184                 if (next && next->s != DIFF_SYMBOL_PLUS &&
1185                             next->s != DIFF_SYMBOL_MINUS)
1186                         next = NULL;
1187
1188                 /* Inside a block? */
1189                 if ((prev &&
1190                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1191                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
1192                     (next &&
1193                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1194                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
1195                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1196                         continue;
1197                 }
1198
1199                 /* Check if we are at an interesting bound: */
1200                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
1201                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1202                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1203                         continue;
1204                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
1205                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1206                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1207                         continue;
1208
1209                 /*
1210                  * The boundary to prev and next are not interesting,
1211                  * so this line is not interesting as a whole
1212                  */
1213                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1214         }
1215 }
1216
1217 static void emit_line_ws_markup(struct diff_options *o,
1218                                 const char *set_sign, const char *set,
1219                                 const char *reset,
1220                                 int sign_index, const char *line, int len,
1221                                 unsigned ws_rule, int blank_at_eof)
1222 {
1223         const char *ws = NULL;
1224         int sign = o->output_indicators[sign_index];
1225
1226         if (o->ws_error_highlight & ws_rule) {
1227                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
1228                 if (!*ws)
1229                         ws = NULL;
1230         }
1231
1232         if (!ws && !set_sign)
1233                 emit_line_0(o, set, NULL, 0, reset, sign, line, len);
1234         else if (!ws) {
1235                 emit_line_0(o, set_sign, set, !!set_sign, reset, sign, line, len);
1236         } else if (blank_at_eof)
1237                 /* Blank line at EOF - paint '+' as well */
1238                 emit_line_0(o, ws, NULL, 0, reset, sign, line, len);
1239         else {
1240                 /* Emit just the prefix, then the rest. */
1241                 emit_line_0(o, set_sign ? set_sign : set, NULL, !!set_sign, reset,
1242                             sign, "", 0);
1243                 ws_check_emit(line, len, ws_rule,
1244                               o->file, set, reset, ws);
1245         }
1246 }
1247
1248 static void emit_diff_symbol_from_struct(struct diff_options *o,
1249                                          struct emitted_diff_symbol *eds)
1250 {
1251         static const char *nneof = " No newline at end of file\n";
1252         const char *context, *reset, *set, *set_sign, *meta, *fraginfo;
1253         struct strbuf sb = STRBUF_INIT;
1254
1255         enum diff_symbol s = eds->s;
1256         const char *line = eds->line;
1257         int len = eds->len;
1258         unsigned flags = eds->flags;
1259
1260         switch (s) {
1261         case DIFF_SYMBOL_NO_LF_EOF:
1262                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1263                 reset = diff_get_color_opt(o, DIFF_RESET);
1264                 putc('\n', o->file);
1265                 emit_line_0(o, context, NULL, 0, reset, '\\',
1266                             nneof, strlen(nneof));
1267                 break;
1268         case DIFF_SYMBOL_SUBMODULE_HEADER:
1269         case DIFF_SYMBOL_SUBMODULE_ERROR:
1270         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1271         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1272         case DIFF_SYMBOL_SUMMARY:
1273         case DIFF_SYMBOL_STATS_LINE:
1274         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1275         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1276                 emit_line(o, "", "", line, len);
1277                 break;
1278         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1279         case DIFF_SYMBOL_CONTEXT_MARKER:
1280                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1281                 reset = diff_get_color_opt(o, DIFF_RESET);
1282                 emit_line(o, context, reset, line, len);
1283                 break;
1284         case DIFF_SYMBOL_SEPARATOR:
1285                 fprintf(o->file, "%s%c",
1286                         diff_line_prefix(o),
1287                         o->line_termination);
1288                 break;
1289         case DIFF_SYMBOL_CONTEXT:
1290                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1291                 reset = diff_get_color_opt(o, DIFF_RESET);
1292                 set_sign = NULL;
1293                 if (o->flags.dual_color_diffed_diffs) {
1294                         char c = !len ? 0 : line[0];
1295
1296                         if (c == '+')
1297                                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1298                         else if (c == '@')
1299                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1300                         else if (c == '-')
1301                                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1302                 }
1303                 emit_line_ws_markup(o, set_sign, set, reset,
1304                                     OUTPUT_INDICATOR_CONTEXT, line, len,
1305                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1306                 break;
1307         case DIFF_SYMBOL_PLUS:
1308                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1309                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1310                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1311                 case DIFF_SYMBOL_MOVED_LINE |
1312                      DIFF_SYMBOL_MOVED_LINE_ALT |
1313                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1314                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1315                         break;
1316                 case DIFF_SYMBOL_MOVED_LINE |
1317                      DIFF_SYMBOL_MOVED_LINE_ALT:
1318                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1319                         break;
1320                 case DIFF_SYMBOL_MOVED_LINE |
1321                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1322                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1323                         break;
1324                 case DIFF_SYMBOL_MOVED_LINE:
1325                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1326                         break;
1327                 default:
1328                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1329                 }
1330                 reset = diff_get_color_opt(o, DIFF_RESET);
1331                 if (!o->flags.dual_color_diffed_diffs)
1332                         set_sign = NULL;
1333                 else {
1334                         char c = !len ? 0 : line[0];
1335
1336                         set_sign = set;
1337                         if (c == '-')
1338                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_BOLD);
1339                         else if (c == '@')
1340                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1341                         else if (c == '+')
1342                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_BOLD);
1343                         else
1344                                 set = diff_get_color_opt(o, DIFF_CONTEXT_BOLD);
1345                         flags &= ~DIFF_SYMBOL_CONTENT_WS_MASK;
1346                 }
1347                 emit_line_ws_markup(o, set_sign, set, reset,
1348                                     OUTPUT_INDICATOR_NEW, line, len,
1349                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1350                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1351                 break;
1352         case DIFF_SYMBOL_MINUS:
1353                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1354                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1355                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1356                 case DIFF_SYMBOL_MOVED_LINE |
1357                      DIFF_SYMBOL_MOVED_LINE_ALT |
1358                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1359                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1360                         break;
1361                 case DIFF_SYMBOL_MOVED_LINE |
1362                      DIFF_SYMBOL_MOVED_LINE_ALT:
1363                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1364                         break;
1365                 case DIFF_SYMBOL_MOVED_LINE |
1366                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1367                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1368                         break;
1369                 case DIFF_SYMBOL_MOVED_LINE:
1370                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1371                         break;
1372                 default:
1373                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1374                 }
1375                 reset = diff_get_color_opt(o, DIFF_RESET);
1376                 if (!o->flags.dual_color_diffed_diffs)
1377                         set_sign = NULL;
1378                 else {
1379                         char c = !len ? 0 : line[0];
1380
1381                         set_sign = set;
1382                         if (c == '+')
1383                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_DIM);
1384                         else if (c == '@')
1385                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1386                         else if (c == '-')
1387                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_DIM);
1388                         else
1389                                 set = diff_get_color_opt(o, DIFF_CONTEXT_DIM);
1390                 }
1391                 emit_line_ws_markup(o, set_sign, set, reset,
1392                                     OUTPUT_INDICATOR_OLD, line, len,
1393                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1394                 break;
1395         case DIFF_SYMBOL_WORDS_PORCELAIN:
1396                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1397                 reset = diff_get_color_opt(o, DIFF_RESET);
1398                 emit_line(o, context, reset, line, len);
1399                 fputs("~\n", o->file);
1400                 break;
1401         case DIFF_SYMBOL_WORDS:
1402                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1403                 reset = diff_get_color_opt(o, DIFF_RESET);
1404                 /*
1405                  * Skip the prefix character, if any.  With
1406                  * diff_suppress_blank_empty, there may be
1407                  * none.
1408                  */
1409                 if (line[0] != '\n') {
1410                         line++;
1411                         len--;
1412                 }
1413                 emit_line(o, context, reset, line, len);
1414                 break;
1415         case DIFF_SYMBOL_FILEPAIR_PLUS:
1416                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1417                 reset = diff_get_color_opt(o, DIFF_RESET);
1418                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1419                         line, reset,
1420                         strchr(line, ' ') ? "\t" : "");
1421                 break;
1422         case DIFF_SYMBOL_FILEPAIR_MINUS:
1423                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1424                 reset = diff_get_color_opt(o, DIFF_RESET);
1425                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1426                         line, reset,
1427                         strchr(line, ' ') ? "\t" : "");
1428                 break;
1429         case DIFF_SYMBOL_BINARY_FILES:
1430         case DIFF_SYMBOL_HEADER:
1431                 fprintf(o->file, "%s", line);
1432                 break;
1433         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1434                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1435                 break;
1436         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1437                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1438                 break;
1439         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1440                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1441                 break;
1442         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1443                 fputs(diff_line_prefix(o), o->file);
1444                 fputc('\n', o->file);
1445                 break;
1446         case DIFF_SYMBOL_REWRITE_DIFF:
1447                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1448                 reset = diff_get_color_opt(o, DIFF_RESET);
1449                 emit_line(o, fraginfo, reset, line, len);
1450                 break;
1451         case DIFF_SYMBOL_SUBMODULE_ADD:
1452                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1453                 reset = diff_get_color_opt(o, DIFF_RESET);
1454                 emit_line(o, set, reset, line, len);
1455                 break;
1456         case DIFF_SYMBOL_SUBMODULE_DEL:
1457                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1458                 reset = diff_get_color_opt(o, DIFF_RESET);
1459                 emit_line(o, set, reset, line, len);
1460                 break;
1461         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1462                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1463                         diff_line_prefix(o), line);
1464                 break;
1465         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1466                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1467                         diff_line_prefix(o), line);
1468                 break;
1469         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1470                 emit_line(o, "", "", " 0 files changed\n",
1471                           strlen(" 0 files changed\n"));
1472                 break;
1473         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1474                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1475                 break;
1476         case DIFF_SYMBOL_WORD_DIFF:
1477                 fprintf(o->file, "%.*s", len, line);
1478                 break;
1479         case DIFF_SYMBOL_STAT_SEP:
1480                 fputs(o->stat_sep, o->file);
1481                 break;
1482         default:
1483                 BUG("unknown diff symbol");
1484         }
1485         strbuf_release(&sb);
1486 }
1487
1488 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1489                              const char *line, int len, unsigned flags)
1490 {
1491         struct emitted_diff_symbol e = {line, len, flags, s};
1492
1493         if (o->emitted_symbols)
1494                 append_emitted_diff_symbol(o, &e);
1495         else
1496                 emit_diff_symbol_from_struct(o, &e);
1497 }
1498
1499 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1500 {
1501         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1502 }
1503
1504 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1505 {
1506         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1507 }
1508
1509 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1510 {
1511         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1512                          path, strlen(path), 0);
1513 }
1514
1515 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1516 {
1517         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1518                          path, strlen(path), 0);
1519 }
1520
1521 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1522 {
1523         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1524                          header, strlen(header), 0);
1525 }
1526
1527 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1528 {
1529         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1530 }
1531
1532 void diff_emit_submodule_pipethrough(struct diff_options *o,
1533                                      const char *line, int len)
1534 {
1535         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1536 }
1537
1538 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1539 {
1540         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1541               ecbdata->blank_at_eof_in_preimage &&
1542               ecbdata->blank_at_eof_in_postimage &&
1543               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1544               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1545                 return 0;
1546         return ws_blank_line(line, len, ecbdata->ws_rule);
1547 }
1548
1549 static void emit_add_line(const char *reset,
1550                           struct emit_callback *ecbdata,
1551                           const char *line, int len)
1552 {
1553         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1554         if (new_blank_line_at_eof(ecbdata, line, len))
1555                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1556
1557         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1558 }
1559
1560 static void emit_del_line(const char *reset,
1561                           struct emit_callback *ecbdata,
1562                           const char *line, int len)
1563 {
1564         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1565         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1566 }
1567
1568 static void emit_context_line(const char *reset,
1569                               struct emit_callback *ecbdata,
1570                               const char *line, int len)
1571 {
1572         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1573         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1574 }
1575
1576 static void emit_hunk_header(struct emit_callback *ecbdata,
1577                              const char *line, int len)
1578 {
1579         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1580         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1581         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1582         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1583         const char *reverse = ecbdata->color_diff ? GIT_COLOR_REVERSE : "";
1584         static const char atat[2] = { '@', '@' };
1585         const char *cp, *ep;
1586         struct strbuf msgbuf = STRBUF_INIT;
1587         int org_len = len;
1588         int i = 1;
1589
1590         /*
1591          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1592          * it always is at least 10 bytes long.
1593          */
1594         if (len < 10 ||
1595             memcmp(line, atat, 2) ||
1596             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1597                 emit_diff_symbol(ecbdata->opt,
1598                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1599                 return;
1600         }
1601         ep += 2; /* skip over @@ */
1602
1603         /* The hunk header in fraginfo color */
1604         if (ecbdata->opt->flags.dual_color_diffed_diffs)
1605                 strbuf_addstr(&msgbuf, reverse);
1606         strbuf_addstr(&msgbuf, frag);
1607         strbuf_add(&msgbuf, line, ep - line);
1608         strbuf_addstr(&msgbuf, reset);
1609
1610         /*
1611          * trailing "\r\n"
1612          */
1613         for ( ; i < 3; i++)
1614                 if (line[len - i] == '\r' || line[len - i] == '\n')
1615                         len--;
1616
1617         /* blank before the func header */
1618         for (cp = ep; ep - line < len; ep++)
1619                 if (*ep != ' ' && *ep != '\t')
1620                         break;
1621         if (ep != cp) {
1622                 strbuf_addstr(&msgbuf, context);
1623                 strbuf_add(&msgbuf, cp, ep - cp);
1624                 strbuf_addstr(&msgbuf, reset);
1625         }
1626
1627         if (ep < line + len) {
1628                 strbuf_addstr(&msgbuf, func);
1629                 strbuf_add(&msgbuf, ep, line + len - ep);
1630                 strbuf_addstr(&msgbuf, reset);
1631         }
1632
1633         strbuf_add(&msgbuf, line + len, org_len - len);
1634         strbuf_complete_line(&msgbuf);
1635         emit_diff_symbol(ecbdata->opt,
1636                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1637         strbuf_release(&msgbuf);
1638 }
1639
1640 static struct diff_tempfile *claim_diff_tempfile(void) {
1641         int i;
1642         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1643                 if (!diff_temp[i].name)
1644                         return diff_temp + i;
1645         BUG("diff is failing to clean up its tempfiles");
1646 }
1647
1648 static void remove_tempfile(void)
1649 {
1650         int i;
1651         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1652                 if (is_tempfile_active(diff_temp[i].tempfile))
1653                         delete_tempfile(&diff_temp[i].tempfile);
1654                 diff_temp[i].name = NULL;
1655         }
1656 }
1657
1658 static void add_line_count(struct strbuf *out, int count)
1659 {
1660         switch (count) {
1661         case 0:
1662                 strbuf_addstr(out, "0,0");
1663                 break;
1664         case 1:
1665                 strbuf_addstr(out, "1");
1666                 break;
1667         default:
1668                 strbuf_addf(out, "1,%d", count);
1669                 break;
1670         }
1671 }
1672
1673 static void emit_rewrite_lines(struct emit_callback *ecb,
1674                                int prefix, const char *data, int size)
1675 {
1676         const char *endp = NULL;
1677         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1678
1679         while (0 < size) {
1680                 int len;
1681
1682                 endp = memchr(data, '\n', size);
1683                 len = endp ? (endp - data + 1) : size;
1684                 if (prefix != '+') {
1685                         ecb->lno_in_preimage++;
1686                         emit_del_line(reset, ecb, data, len);
1687                 } else {
1688                         ecb->lno_in_postimage++;
1689                         emit_add_line(reset, ecb, data, len);
1690                 }
1691                 size -= len;
1692                 data += len;
1693         }
1694         if (!endp)
1695                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1696 }
1697
1698 static void emit_rewrite_diff(const char *name_a,
1699                               const char *name_b,
1700                               struct diff_filespec *one,
1701                               struct diff_filespec *two,
1702                               struct userdiff_driver *textconv_one,
1703                               struct userdiff_driver *textconv_two,
1704                               struct diff_options *o)
1705 {
1706         int lc_a, lc_b;
1707         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1708         const char *a_prefix, *b_prefix;
1709         char *data_one, *data_two;
1710         size_t size_one, size_two;
1711         struct emit_callback ecbdata;
1712         struct strbuf out = STRBUF_INIT;
1713
1714         if (diff_mnemonic_prefix && o->flags.reverse_diff) {
1715                 a_prefix = o->b_prefix;
1716                 b_prefix = o->a_prefix;
1717         } else {
1718                 a_prefix = o->a_prefix;
1719                 b_prefix = o->b_prefix;
1720         }
1721
1722         name_a += (*name_a == '/');
1723         name_b += (*name_b == '/');
1724
1725         strbuf_reset(&a_name);
1726         strbuf_reset(&b_name);
1727         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1728         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1729
1730         size_one = fill_textconv(o->repo, textconv_one, one, &data_one);
1731         size_two = fill_textconv(o->repo, textconv_two, two, &data_two);
1732
1733         memset(&ecbdata, 0, sizeof(ecbdata));
1734         ecbdata.color_diff = want_color(o->use_color);
1735         ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
1736         ecbdata.opt = o;
1737         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1738                 mmfile_t mf1, mf2;
1739                 mf1.ptr = (char *)data_one;
1740                 mf2.ptr = (char *)data_two;
1741                 mf1.size = size_one;
1742                 mf2.size = size_two;
1743                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1744         }
1745         ecbdata.lno_in_preimage = 1;
1746         ecbdata.lno_in_postimage = 1;
1747
1748         lc_a = count_lines(data_one, size_one);
1749         lc_b = count_lines(data_two, size_two);
1750
1751         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1752                          a_name.buf, a_name.len, 0);
1753         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1754                          b_name.buf, b_name.len, 0);
1755
1756         strbuf_addstr(&out, "@@ -");
1757         if (!o->irreversible_delete)
1758                 add_line_count(&out, lc_a);
1759         else
1760                 strbuf_addstr(&out, "?,?");
1761         strbuf_addstr(&out, " +");
1762         add_line_count(&out, lc_b);
1763         strbuf_addstr(&out, " @@\n");
1764         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1765         strbuf_release(&out);
1766
1767         if (lc_a && !o->irreversible_delete)
1768                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1769         if (lc_b)
1770                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1771         if (textconv_one)
1772                 free((char *)data_one);
1773         if (textconv_two)
1774                 free((char *)data_two);
1775 }
1776
1777 struct diff_words_buffer {
1778         mmfile_t text;
1779         unsigned long alloc;
1780         struct diff_words_orig {
1781                 const char *begin, *end;
1782         } *orig;
1783         int orig_nr, orig_alloc;
1784 };
1785
1786 static void diff_words_append(char *line, unsigned long len,
1787                 struct diff_words_buffer *buffer)
1788 {
1789         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1790         line++;
1791         len--;
1792         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1793         buffer->text.size += len;
1794         buffer->text.ptr[buffer->text.size] = '\0';
1795 }
1796
1797 struct diff_words_style_elem {
1798         const char *prefix;
1799         const char *suffix;
1800         const char *color; /* NULL; filled in by the setup code if
1801                             * color is enabled */
1802 };
1803
1804 struct diff_words_style {
1805         enum diff_words_type type;
1806         struct diff_words_style_elem new_word, old_word, ctx;
1807         const char *newline;
1808 };
1809
1810 static struct diff_words_style diff_words_styles[] = {
1811         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1812         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1813         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1814 };
1815
1816 struct diff_words_data {
1817         struct diff_words_buffer minus, plus;
1818         const char *current_plus;
1819         int last_minus;
1820         struct diff_options *opt;
1821         regex_t *word_regex;
1822         enum diff_words_type type;
1823         struct diff_words_style *style;
1824 };
1825
1826 static int fn_out_diff_words_write_helper(struct diff_options *o,
1827                                           struct diff_words_style_elem *st_el,
1828                                           const char *newline,
1829                                           size_t count, const char *buf)
1830 {
1831         int print = 0;
1832         struct strbuf sb = STRBUF_INIT;
1833
1834         while (count) {
1835                 char *p = memchr(buf, '\n', count);
1836                 if (print)
1837                         strbuf_addstr(&sb, diff_line_prefix(o));
1838
1839                 if (p != buf) {
1840                         const char *reset = st_el->color && *st_el->color ?
1841                                             GIT_COLOR_RESET : NULL;
1842                         if (st_el->color && *st_el->color)
1843                                 strbuf_addstr(&sb, st_el->color);
1844                         strbuf_addstr(&sb, st_el->prefix);
1845                         strbuf_add(&sb, buf, p ? p - buf : count);
1846                         strbuf_addstr(&sb, st_el->suffix);
1847                         if (reset)
1848                                 strbuf_addstr(&sb, reset);
1849                 }
1850                 if (!p)
1851                         goto out;
1852
1853                 strbuf_addstr(&sb, newline);
1854                 count -= p + 1 - buf;
1855                 buf = p + 1;
1856                 print = 1;
1857                 if (count) {
1858                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1859                                          sb.buf, sb.len, 0);
1860                         strbuf_reset(&sb);
1861                 }
1862         }
1863
1864 out:
1865         if (sb.len)
1866                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1867                                  sb.buf, sb.len, 0);
1868         strbuf_release(&sb);
1869         return 0;
1870 }
1871
1872 /*
1873  * '--color-words' algorithm can be described as:
1874  *
1875  *   1. collect the minus/plus lines of a diff hunk, divided into
1876  *      minus-lines and plus-lines;
1877  *
1878  *   2. break both minus-lines and plus-lines into words and
1879  *      place them into two mmfile_t with one word for each line;
1880  *
1881  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1882  *
1883  * And for the common parts of the both file, we output the plus side text.
1884  * diff_words->current_plus is used to trace the current position of the plus file
1885  * which printed. diff_words->last_minus is used to trace the last minus word
1886  * printed.
1887  *
1888  * For '--graph' to work with '--color-words', we need to output the graph prefix
1889  * on each line of color words output. Generally, there are two conditions on
1890  * which we should output the prefix.
1891  *
1892  *   1. diff_words->last_minus == 0 &&
1893  *      diff_words->current_plus == diff_words->plus.text.ptr
1894  *
1895  *      that is: the plus text must start as a new line, and if there is no minus
1896  *      word printed, a graph prefix must be printed.
1897  *
1898  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1899  *      *(diff_words->current_plus - 1) == '\n'
1900  *
1901  *      that is: a graph prefix must be printed following a '\n'
1902  */
1903 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1904 {
1905         if ((diff_words->last_minus == 0 &&
1906                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1907                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1908                 *(diff_words->current_plus - 1) == '\n')) {
1909                 return 1;
1910         } else {
1911                 return 0;
1912         }
1913 }
1914
1915 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1916 {
1917         struct diff_words_data *diff_words = priv;
1918         struct diff_words_style *style = diff_words->style;
1919         int minus_first, minus_len, plus_first, plus_len;
1920         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1921         struct diff_options *opt = diff_words->opt;
1922         const char *line_prefix;
1923
1924         if (line[0] != '@' || parse_hunk_header(line, len,
1925                         &minus_first, &minus_len, &plus_first, &plus_len))
1926                 return;
1927
1928         assert(opt);
1929         line_prefix = diff_line_prefix(opt);
1930
1931         /* POSIX requires that first be decremented by one if len == 0... */
1932         if (minus_len) {
1933                 minus_begin = diff_words->minus.orig[minus_first].begin;
1934                 minus_end =
1935                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1936         } else
1937                 minus_begin = minus_end =
1938                         diff_words->minus.orig[minus_first].end;
1939
1940         if (plus_len) {
1941                 plus_begin = diff_words->plus.orig[plus_first].begin;
1942                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1943         } else
1944                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1945
1946         if (color_words_output_graph_prefix(diff_words)) {
1947                 fputs(line_prefix, diff_words->opt->file);
1948         }
1949         if (diff_words->current_plus != plus_begin) {
1950                 fn_out_diff_words_write_helper(diff_words->opt,
1951                                 &style->ctx, style->newline,
1952                                 plus_begin - diff_words->current_plus,
1953                                 diff_words->current_plus);
1954         }
1955         if (minus_begin != minus_end) {
1956                 fn_out_diff_words_write_helper(diff_words->opt,
1957                                 &style->old_word, style->newline,
1958                                 minus_end - minus_begin, minus_begin);
1959         }
1960         if (plus_begin != plus_end) {
1961                 fn_out_diff_words_write_helper(diff_words->opt,
1962                                 &style->new_word, style->newline,
1963                                 plus_end - plus_begin, plus_begin);
1964         }
1965
1966         diff_words->current_plus = plus_end;
1967         diff_words->last_minus = minus_first;
1968 }
1969
1970 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1971 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1972                 int *begin, int *end)
1973 {
1974         if (word_regex && *begin < buffer->size) {
1975                 regmatch_t match[1];
1976                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1977                                  buffer->size - *begin, 1, match, 0)) {
1978                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1979                                         '\n', match[0].rm_eo - match[0].rm_so);
1980                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1981                         *begin += match[0].rm_so;
1982                         return *begin >= *end;
1983                 }
1984                 return -1;
1985         }
1986
1987         /* find the next word */
1988         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1989                 (*begin)++;
1990         if (*begin >= buffer->size)
1991                 return -1;
1992
1993         /* find the end of the word */
1994         *end = *begin + 1;
1995         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1996                 (*end)++;
1997
1998         return 0;
1999 }
2000
2001 /*
2002  * This function splits the words in buffer->text, stores the list with
2003  * newline separator into out, and saves the offsets of the original words
2004  * in buffer->orig.
2005  */
2006 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
2007                 regex_t *word_regex)
2008 {
2009         int i, j;
2010         long alloc = 0;
2011
2012         out->size = 0;
2013         out->ptr = NULL;
2014
2015         /* fake an empty "0th" word */
2016         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
2017         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
2018         buffer->orig_nr = 1;
2019
2020         for (i = 0; i < buffer->text.size; i++) {
2021                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
2022                         return;
2023
2024                 /* store original boundaries */
2025                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
2026                                 buffer->orig_alloc);
2027                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
2028                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
2029                 buffer->orig_nr++;
2030
2031                 /* store one word */
2032                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
2033                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
2034                 out->ptr[out->size + j - i] = '\n';
2035                 out->size += j - i + 1;
2036
2037                 i = j - 1;
2038         }
2039 }
2040
2041 /* this executes the word diff on the accumulated buffers */
2042 static void diff_words_show(struct diff_words_data *diff_words)
2043 {
2044         xpparam_t xpp;
2045         xdemitconf_t xecfg;
2046         mmfile_t minus, plus;
2047         struct diff_words_style *style = diff_words->style;
2048
2049         struct diff_options *opt = diff_words->opt;
2050         const char *line_prefix;
2051
2052         assert(opt);
2053         line_prefix = diff_line_prefix(opt);
2054
2055         /* special case: only removal */
2056         if (!diff_words->plus.text.size) {
2057                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2058                                  line_prefix, strlen(line_prefix), 0);
2059                 fn_out_diff_words_write_helper(diff_words->opt,
2060                         &style->old_word, style->newline,
2061                         diff_words->minus.text.size,
2062                         diff_words->minus.text.ptr);
2063                 diff_words->minus.text.size = 0;
2064                 return;
2065         }
2066
2067         diff_words->current_plus = diff_words->plus.text.ptr;
2068         diff_words->last_minus = 0;
2069
2070         memset(&xpp, 0, sizeof(xpp));
2071         memset(&xecfg, 0, sizeof(xecfg));
2072         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
2073         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
2074         xpp.flags = 0;
2075         /* as only the hunk header will be parsed, we need a 0-context */
2076         xecfg.ctxlen = 0;
2077         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
2078                           &xpp, &xecfg))
2079                 die("unable to generate word diff");
2080         free(minus.ptr);
2081         free(plus.ptr);
2082         if (diff_words->current_plus != diff_words->plus.text.ptr +
2083                         diff_words->plus.text.size) {
2084                 if (color_words_output_graph_prefix(diff_words))
2085                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2086                                          line_prefix, strlen(line_prefix), 0);
2087                 fn_out_diff_words_write_helper(diff_words->opt,
2088                         &style->ctx, style->newline,
2089                         diff_words->plus.text.ptr + diff_words->plus.text.size
2090                         - diff_words->current_plus, diff_words->current_plus);
2091         }
2092         diff_words->minus.text.size = diff_words->plus.text.size = 0;
2093 }
2094
2095 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
2096 static void diff_words_flush(struct emit_callback *ecbdata)
2097 {
2098         struct diff_options *wo = ecbdata->diff_words->opt;
2099
2100         if (ecbdata->diff_words->minus.text.size ||
2101             ecbdata->diff_words->plus.text.size)
2102                 diff_words_show(ecbdata->diff_words);
2103
2104         if (wo->emitted_symbols) {
2105                 struct diff_options *o = ecbdata->opt;
2106                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
2107                 int i;
2108
2109                 /*
2110                  * NEEDSWORK:
2111                  * Instead of appending each, concat all words to a line?
2112                  */
2113                 for (i = 0; i < wol->nr; i++)
2114                         append_emitted_diff_symbol(o, &wol->buf[i]);
2115
2116                 for (i = 0; i < wol->nr; i++)
2117                         free((void *)wol->buf[i].line);
2118
2119                 wol->nr = 0;
2120         }
2121 }
2122
2123 static void diff_filespec_load_driver(struct diff_filespec *one,
2124                                       struct index_state *istate)
2125 {
2126         /* Use already-loaded driver */
2127         if (one->driver)
2128                 return;
2129
2130         if (S_ISREG(one->mode))
2131                 one->driver = userdiff_find_by_path(istate, one->path);
2132
2133         /* Fallback to default settings */
2134         if (!one->driver)
2135                 one->driver = userdiff_find_by_name("default");
2136 }
2137
2138 static const char *userdiff_word_regex(struct diff_filespec *one,
2139                                        struct index_state *istate)
2140 {
2141         diff_filespec_load_driver(one, istate);
2142         return one->driver->word_regex;
2143 }
2144
2145 static void init_diff_words_data(struct emit_callback *ecbdata,
2146                                  struct diff_options *orig_opts,
2147                                  struct diff_filespec *one,
2148                                  struct diff_filespec *two)
2149 {
2150         int i;
2151         struct diff_options *o = xmalloc(sizeof(struct diff_options));
2152         memcpy(o, orig_opts, sizeof(struct diff_options));
2153
2154         ecbdata->diff_words =
2155                 xcalloc(1, sizeof(struct diff_words_data));
2156         ecbdata->diff_words->type = o->word_diff;
2157         ecbdata->diff_words->opt = o;
2158
2159         if (orig_opts->emitted_symbols)
2160                 o->emitted_symbols =
2161                         xcalloc(1, sizeof(struct emitted_diff_symbols));
2162
2163         if (!o->word_regex)
2164                 o->word_regex = userdiff_word_regex(one, o->repo->index);
2165         if (!o->word_regex)
2166                 o->word_regex = userdiff_word_regex(two, o->repo->index);
2167         if (!o->word_regex)
2168                 o->word_regex = diff_word_regex_cfg;
2169         if (o->word_regex) {
2170                 ecbdata->diff_words->word_regex = (regex_t *)
2171                         xmalloc(sizeof(regex_t));
2172                 if (regcomp(ecbdata->diff_words->word_regex,
2173                             o->word_regex,
2174                             REG_EXTENDED | REG_NEWLINE))
2175                         die("invalid regular expression: %s",
2176                             o->word_regex);
2177         }
2178         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2179                 if (o->word_diff == diff_words_styles[i].type) {
2180                         ecbdata->diff_words->style =
2181                                 &diff_words_styles[i];
2182                         break;
2183                 }
2184         }
2185         if (want_color(o->use_color)) {
2186                 struct diff_words_style *st = ecbdata->diff_words->style;
2187                 st->old_word.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2188                 st->new_word.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2189                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
2190         }
2191 }
2192
2193 static void free_diff_words_data(struct emit_callback *ecbdata)
2194 {
2195         if (ecbdata->diff_words) {
2196                 diff_words_flush(ecbdata);
2197                 free (ecbdata->diff_words->opt->emitted_symbols);
2198                 free (ecbdata->diff_words->opt);
2199                 free (ecbdata->diff_words->minus.text.ptr);
2200                 free (ecbdata->diff_words->minus.orig);
2201                 free (ecbdata->diff_words->plus.text.ptr);
2202                 free (ecbdata->diff_words->plus.orig);
2203                 if (ecbdata->diff_words->word_regex) {
2204                         regfree(ecbdata->diff_words->word_regex);
2205                         free(ecbdata->diff_words->word_regex);
2206                 }
2207                 FREE_AND_NULL(ecbdata->diff_words);
2208         }
2209 }
2210
2211 const char *diff_get_color(int diff_use_color, enum color_diff ix)
2212 {
2213         if (want_color(diff_use_color))
2214                 return diff_colors[ix];
2215         return "";
2216 }
2217
2218 const char *diff_line_prefix(struct diff_options *opt)
2219 {
2220         struct strbuf *msgbuf;
2221         if (!opt->output_prefix)
2222                 return "";
2223
2224         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
2225         return msgbuf->buf;
2226 }
2227
2228 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
2229 {
2230         const char *cp;
2231         unsigned long allot;
2232         size_t l = len;
2233
2234         cp = line;
2235         allot = l;
2236         while (0 < l) {
2237                 (void) utf8_width(&cp, &l);
2238                 if (!cp)
2239                         break; /* truncated in the middle? */
2240         }
2241         return allot - l;
2242 }
2243
2244 static void find_lno(const char *line, struct emit_callback *ecbdata)
2245 {
2246         const char *p;
2247         ecbdata->lno_in_preimage = 0;
2248         ecbdata->lno_in_postimage = 0;
2249         p = strchr(line, '-');
2250         if (!p)
2251                 return; /* cannot happen */
2252         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
2253         p = strchr(p, '+');
2254         if (!p)
2255                 return; /* cannot happen */
2256         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
2257 }
2258
2259 static void fn_out_consume(void *priv, char *line, unsigned long len)
2260 {
2261         struct emit_callback *ecbdata = priv;
2262         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
2263         struct diff_options *o = ecbdata->opt;
2264
2265         o->found_changes = 1;
2266
2267         if (ecbdata->header) {
2268                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2269                                  ecbdata->header->buf, ecbdata->header->len, 0);
2270                 strbuf_reset(ecbdata->header);
2271                 ecbdata->header = NULL;
2272         }
2273
2274         if (ecbdata->label_path[0]) {
2275                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
2276                                  ecbdata->label_path[0],
2277                                  strlen(ecbdata->label_path[0]), 0);
2278                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
2279                                  ecbdata->label_path[1],
2280                                  strlen(ecbdata->label_path[1]), 0);
2281                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
2282         }
2283
2284         if (diff_suppress_blank_empty
2285             && len == 2 && line[0] == ' ' && line[1] == '\n') {
2286                 line[0] = '\n';
2287                 len = 1;
2288         }
2289
2290         if (line[0] == '@') {
2291                 if (ecbdata->diff_words)
2292                         diff_words_flush(ecbdata);
2293                 len = sane_truncate_line(ecbdata, line, len);
2294                 find_lno(line, ecbdata);
2295                 emit_hunk_header(ecbdata, line, len);
2296                 return;
2297         }
2298
2299         if (ecbdata->diff_words) {
2300                 enum diff_symbol s =
2301                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2302                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2303                 if (line[0] == '-') {
2304                         diff_words_append(line, len,
2305                                           &ecbdata->diff_words->minus);
2306                         return;
2307                 } else if (line[0] == '+') {
2308                         diff_words_append(line, len,
2309                                           &ecbdata->diff_words->plus);
2310                         return;
2311                 } else if (starts_with(line, "\\ ")) {
2312                         /*
2313                          * Eat the "no newline at eof" marker as if we
2314                          * saw a "+" or "-" line with nothing on it,
2315                          * and return without diff_words_flush() to
2316                          * defer processing. If this is the end of
2317                          * preimage, more "+" lines may come after it.
2318                          */
2319                         return;
2320                 }
2321                 diff_words_flush(ecbdata);
2322                 emit_diff_symbol(o, s, line, len, 0);
2323                 return;
2324         }
2325
2326         switch (line[0]) {
2327         case '+':
2328                 ecbdata->lno_in_postimage++;
2329                 emit_add_line(reset, ecbdata, line + 1, len - 1);
2330                 break;
2331         case '-':
2332                 ecbdata->lno_in_preimage++;
2333                 emit_del_line(reset, ecbdata, line + 1, len - 1);
2334                 break;
2335         case ' ':
2336                 ecbdata->lno_in_postimage++;
2337                 ecbdata->lno_in_preimage++;
2338                 emit_context_line(reset, ecbdata, line + 1, len - 1);
2339                 break;
2340         default:
2341                 /* incomplete line at the end */
2342                 ecbdata->lno_in_preimage++;
2343                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2344                                  line, len, 0);
2345                 break;
2346         }
2347 }
2348
2349 static void pprint_rename(struct strbuf *name, const char *a, const char *b)
2350 {
2351         const char *old_name = a;
2352         const char *new_name = b;
2353         int pfx_length, sfx_length;
2354         int pfx_adjust_for_slash;
2355         int len_a = strlen(a);
2356         int len_b = strlen(b);
2357         int a_midlen, b_midlen;
2358         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2359         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2360
2361         if (qlen_a || qlen_b) {
2362                 quote_c_style(a, name, NULL, 0);
2363                 strbuf_addstr(name, " => ");
2364                 quote_c_style(b, name, NULL, 0);
2365                 return;
2366         }
2367
2368         /* Find common prefix */
2369         pfx_length = 0;
2370         while (*old_name && *new_name && *old_name == *new_name) {
2371                 if (*old_name == '/')
2372                         pfx_length = old_name - a + 1;
2373                 old_name++;
2374                 new_name++;
2375         }
2376
2377         /* Find common suffix */
2378         old_name = a + len_a;
2379         new_name = b + len_b;
2380         sfx_length = 0;
2381         /*
2382          * If there is a common prefix, it must end in a slash.  In
2383          * that case we let this loop run 1 into the prefix to see the
2384          * same slash.
2385          *
2386          * If there is no common prefix, we cannot do this as it would
2387          * underrun the input strings.
2388          */
2389         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2390         while (a + pfx_length - pfx_adjust_for_slash <= old_name &&
2391                b + pfx_length - pfx_adjust_for_slash <= new_name &&
2392                *old_name == *new_name) {
2393                 if (*old_name == '/')
2394                         sfx_length = len_a - (old_name - a);
2395                 old_name--;
2396                 new_name--;
2397         }
2398
2399         /*
2400          * pfx{mid-a => mid-b}sfx
2401          * {pfx-a => pfx-b}sfx
2402          * pfx{sfx-a => sfx-b}
2403          * name-a => name-b
2404          */
2405         a_midlen = len_a - pfx_length - sfx_length;
2406         b_midlen = len_b - pfx_length - sfx_length;
2407         if (a_midlen < 0)
2408                 a_midlen = 0;
2409         if (b_midlen < 0)
2410                 b_midlen = 0;
2411
2412         strbuf_grow(name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2413         if (pfx_length + sfx_length) {
2414                 strbuf_add(name, a, pfx_length);
2415                 strbuf_addch(name, '{');
2416         }
2417         strbuf_add(name, a + pfx_length, a_midlen);
2418         strbuf_addstr(name, " => ");
2419         strbuf_add(name, b + pfx_length, b_midlen);
2420         if (pfx_length + sfx_length) {
2421                 strbuf_addch(name, '}');
2422                 strbuf_add(name, a + len_a - sfx_length, sfx_length);
2423         }
2424 }
2425
2426 struct diffstat_t {
2427         int nr;
2428         int alloc;
2429         struct diffstat_file {
2430                 char *from_name;
2431                 char *name;
2432                 char *print_name;
2433                 const char *comments;
2434                 unsigned is_unmerged:1;
2435                 unsigned is_binary:1;
2436                 unsigned is_renamed:1;
2437                 unsigned is_interesting:1;
2438                 uintmax_t added, deleted;
2439         } **files;
2440 };
2441
2442 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2443                                           const char *name_a,
2444                                           const char *name_b)
2445 {
2446         struct diffstat_file *x;
2447         x = xcalloc(1, sizeof(*x));
2448         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2449         diffstat->files[diffstat->nr++] = x;
2450         if (name_b) {
2451                 x->from_name = xstrdup(name_a);
2452                 x->name = xstrdup(name_b);
2453                 x->is_renamed = 1;
2454         }
2455         else {
2456                 x->from_name = NULL;
2457                 x->name = xstrdup(name_a);
2458         }
2459         return x;
2460 }
2461
2462 static void diffstat_consume(void *priv, char *line, unsigned long len)
2463 {
2464         struct diffstat_t *diffstat = priv;
2465         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2466
2467         if (line[0] == '+')
2468                 x->added++;
2469         else if (line[0] == '-')
2470                 x->deleted++;
2471 }
2472
2473 const char mime_boundary_leader[] = "------------";
2474
2475 static int scale_linear(int it, int width, int max_change)
2476 {
2477         if (!it)
2478                 return 0;
2479         /*
2480          * make sure that at least one '-' or '+' is printed if
2481          * there is any change to this path. The easiest way is to
2482          * scale linearly as if the alloted width is one column shorter
2483          * than it is, and then add 1 to the result.
2484          */
2485         return 1 + (it * (width - 1) / max_change);
2486 }
2487
2488 static void show_graph(struct strbuf *out, char ch, int cnt,
2489                        const char *set, const char *reset)
2490 {
2491         if (cnt <= 0)
2492                 return;
2493         strbuf_addstr(out, set);
2494         strbuf_addchars(out, ch, cnt);
2495         strbuf_addstr(out, reset);
2496 }
2497
2498 static void fill_print_name(struct diffstat_file *file)
2499 {
2500         struct strbuf pname = STRBUF_INIT;
2501
2502         if (file->print_name)
2503                 return;
2504
2505         if (file->is_renamed)
2506                 pprint_rename(&pname, file->from_name, file->name);
2507         else
2508                 quote_c_style(file->name, &pname, NULL, 0);
2509
2510         if (file->comments)
2511                 strbuf_addf(&pname, " (%s)", file->comments);
2512
2513         file->print_name = strbuf_detach(&pname, NULL);
2514 }
2515
2516 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2517                 int files, int insertions, int deletions)
2518 {
2519         struct strbuf sb = STRBUF_INIT;
2520
2521         if (!files) {
2522                 assert(insertions == 0 && deletions == 0);
2523                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2524                                  NULL, 0, 0);
2525                 return;
2526         }
2527
2528         strbuf_addf(&sb,
2529                     (files == 1) ? " %d file changed" : " %d files changed",
2530                     files);
2531
2532         /*
2533          * For binary diff, the caller may want to print "x files
2534          * changed" with insertions == 0 && deletions == 0.
2535          *
2536          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2537          * is probably less confusing (i.e skip over "2 files changed
2538          * but nothing about added/removed lines? Is this a bug in Git?").
2539          */
2540         if (insertions || deletions == 0) {
2541                 strbuf_addf(&sb,
2542                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2543                             insertions);
2544         }
2545
2546         if (deletions || insertions == 0) {
2547                 strbuf_addf(&sb,
2548                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2549                             deletions);
2550         }
2551         strbuf_addch(&sb, '\n');
2552         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2553                          sb.buf, sb.len, 0);
2554         strbuf_release(&sb);
2555 }
2556
2557 void print_stat_summary(FILE *fp, int files,
2558                         int insertions, int deletions)
2559 {
2560         struct diff_options o;
2561         memset(&o, 0, sizeof(o));
2562         o.file = fp;
2563
2564         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2565 }
2566
2567 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2568 {
2569         int i, len, add, del, adds = 0, dels = 0;
2570         uintmax_t max_change = 0, max_len = 0;
2571         int total_files = data->nr, count;
2572         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2573         const char *reset, *add_c, *del_c;
2574         int extra_shown = 0;
2575         const char *line_prefix = diff_line_prefix(options);
2576         struct strbuf out = STRBUF_INIT;
2577
2578         if (data->nr == 0)
2579                 return;
2580
2581         count = options->stat_count ? options->stat_count : data->nr;
2582
2583         reset = diff_get_color_opt(options, DIFF_RESET);
2584         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2585         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2586
2587         /*
2588          * Find the longest filename and max number of changes
2589          */
2590         for (i = 0; (i < count) && (i < data->nr); i++) {
2591                 struct diffstat_file *file = data->files[i];
2592                 uintmax_t change = file->added + file->deleted;
2593
2594                 if (!file->is_interesting && (change == 0)) {
2595                         count++; /* not shown == room for one more */
2596                         continue;
2597                 }
2598                 fill_print_name(file);
2599                 len = strlen(file->print_name);
2600                 if (max_len < len)
2601                         max_len = len;
2602
2603                 if (file->is_unmerged) {
2604                         /* "Unmerged" is 8 characters */
2605                         bin_width = bin_width < 8 ? 8 : bin_width;
2606                         continue;
2607                 }
2608                 if (file->is_binary) {
2609                         /* "Bin XXX -> YYY bytes" */
2610                         int w = 14 + decimal_width(file->added)
2611                                 + decimal_width(file->deleted);
2612                         bin_width = bin_width < w ? w : bin_width;
2613                         /* Display change counts aligned with "Bin" */
2614                         number_width = 3;
2615                         continue;
2616                 }
2617
2618                 if (max_change < change)
2619                         max_change = change;
2620         }
2621         count = i; /* where we can stop scanning in data->files[] */
2622
2623         /*
2624          * We have width = stat_width or term_columns() columns total.
2625          * We want a maximum of min(max_len, stat_name_width) for the name part.
2626          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2627          * We also need 1 for " " and 4 + decimal_width(max_change)
2628          * for " | NNNN " and one the empty column at the end, altogether
2629          * 6 + decimal_width(max_change).
2630          *
2631          * If there's not enough space, we will use the smaller of
2632          * stat_name_width (if set) and 5/8*width for the filename,
2633          * and the rest for constant elements + graph part, but no more
2634          * than stat_graph_width for the graph part.
2635          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2636          * for the standard terminal size).
2637          *
2638          * In other words: stat_width limits the maximum width, and
2639          * stat_name_width fixes the maximum width of the filename,
2640          * and is also used to divide available columns if there
2641          * aren't enough.
2642          *
2643          * Binary files are displayed with "Bin XXX -> YYY bytes"
2644          * instead of the change count and graph. This part is treated
2645          * similarly to the graph part, except that it is not
2646          * "scaled". If total width is too small to accommodate the
2647          * guaranteed minimum width of the filename part and the
2648          * separators and this message, this message will "overflow"
2649          * making the line longer than the maximum width.
2650          */
2651
2652         if (options->stat_width == -1)
2653                 width = term_columns() - strlen(line_prefix);
2654         else
2655                 width = options->stat_width ? options->stat_width : 80;
2656         number_width = decimal_width(max_change) > number_width ?
2657                 decimal_width(max_change) : number_width;
2658
2659         if (options->stat_graph_width == -1)
2660                 options->stat_graph_width = diff_stat_graph_width;
2661
2662         /*
2663          * Guarantee 3/8*16==6 for the graph part
2664          * and 5/8*16==10 for the filename part
2665          */
2666         if (width < 16 + 6 + number_width)
2667                 width = 16 + 6 + number_width;
2668
2669         /*
2670          * First assign sizes that are wanted, ignoring available width.
2671          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2672          * starting from "XXX" should fit in graph_width.
2673          */
2674         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2675         if (options->stat_graph_width &&
2676             options->stat_graph_width < graph_width)
2677                 graph_width = options->stat_graph_width;
2678
2679         name_width = (options->stat_name_width > 0 &&
2680                       options->stat_name_width < max_len) ?
2681                 options->stat_name_width : max_len;
2682
2683         /*
2684          * Adjust adjustable widths not to exceed maximum width
2685          */
2686         if (name_width + number_width + 6 + graph_width > width) {
2687                 if (graph_width > width * 3/8 - number_width - 6) {
2688                         graph_width = width * 3/8 - number_width - 6;
2689                         if (graph_width < 6)
2690                                 graph_width = 6;
2691                 }
2692
2693                 if (options->stat_graph_width &&
2694                     graph_width > options->stat_graph_width)
2695                         graph_width = options->stat_graph_width;
2696                 if (name_width > width - number_width - 6 - graph_width)
2697                         name_width = width - number_width - 6 - graph_width;
2698                 else
2699                         graph_width = width - number_width - 6 - name_width;
2700         }
2701
2702         /*
2703          * From here name_width is the width of the name area,
2704          * and graph_width is the width of the graph area.
2705          * max_change is used to scale graph properly.
2706          */
2707         for (i = 0; i < count; i++) {
2708                 const char *prefix = "";
2709                 struct diffstat_file *file = data->files[i];
2710                 char *name = file->print_name;
2711                 uintmax_t added = file->added;
2712                 uintmax_t deleted = file->deleted;
2713                 int name_len;
2714
2715                 if (!file->is_interesting && (added + deleted == 0))
2716                         continue;
2717
2718                 /*
2719                  * "scale" the filename
2720                  */
2721                 len = name_width;
2722                 name_len = strlen(name);
2723                 if (name_width < name_len) {
2724                         char *slash;
2725                         prefix = "...";
2726                         len -= 3;
2727                         name += name_len - len;
2728                         slash = strchr(name, '/');
2729                         if (slash)
2730                                 name = slash;
2731                 }
2732
2733                 if (file->is_binary) {
2734                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2735                         strbuf_addf(&out, " %*s", number_width, "Bin");
2736                         if (!added && !deleted) {
2737                                 strbuf_addch(&out, '\n');
2738                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2739                                                  out.buf, out.len, 0);
2740                                 strbuf_reset(&out);
2741                                 continue;
2742                         }
2743                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2744                                 del_c, deleted, reset);
2745                         strbuf_addstr(&out, " -> ");
2746                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2747                                 add_c, added, reset);
2748                         strbuf_addstr(&out, " bytes\n");
2749                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2750                                          out.buf, out.len, 0);
2751                         strbuf_reset(&out);
2752                         continue;
2753                 }
2754                 else if (file->is_unmerged) {
2755                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2756                         strbuf_addstr(&out, " Unmerged\n");
2757                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2758                                          out.buf, out.len, 0);
2759                         strbuf_reset(&out);
2760                         continue;
2761                 }
2762
2763                 /*
2764                  * scale the add/delete
2765                  */
2766                 add = added;
2767                 del = deleted;
2768
2769                 if (graph_width <= max_change) {
2770                         int total = scale_linear(add + del, graph_width, max_change);
2771                         if (total < 2 && add && del)
2772                                 /* width >= 2 due to the sanity check */
2773                                 total = 2;
2774                         if (add < del) {
2775                                 add = scale_linear(add, graph_width, max_change);
2776                                 del = total - add;
2777                         } else {
2778                                 del = scale_linear(del, graph_width, max_change);
2779                                 add = total - del;
2780                         }
2781                 }
2782                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2783                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2784                         number_width, added + deleted,
2785                         added + deleted ? " " : "");
2786                 show_graph(&out, '+', add, add_c, reset);
2787                 show_graph(&out, '-', del, del_c, reset);
2788                 strbuf_addch(&out, '\n');
2789                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2790                                  out.buf, out.len, 0);
2791                 strbuf_reset(&out);
2792         }
2793
2794         for (i = 0; i < data->nr; i++) {
2795                 struct diffstat_file *file = data->files[i];
2796                 uintmax_t added = file->added;
2797                 uintmax_t deleted = file->deleted;
2798
2799                 if (file->is_unmerged ||
2800                     (!file->is_interesting && (added + deleted == 0))) {
2801                         total_files--;
2802                         continue;
2803                 }
2804
2805                 if (!file->is_binary) {
2806                         adds += added;
2807                         dels += deleted;
2808                 }
2809                 if (i < count)
2810                         continue;
2811                 if (!extra_shown)
2812                         emit_diff_symbol(options,
2813                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2814                                          NULL, 0, 0);
2815                 extra_shown = 1;
2816         }
2817
2818         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2819         strbuf_release(&out);
2820 }
2821
2822 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2823 {
2824         int i, adds = 0, dels = 0, total_files = data->nr;
2825
2826         if (data->nr == 0)
2827                 return;
2828
2829         for (i = 0; i < data->nr; i++) {
2830                 int added = data->files[i]->added;
2831                 int deleted = data->files[i]->deleted;
2832
2833                 if (data->files[i]->is_unmerged ||
2834                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2835                         total_files--;
2836                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2837                         adds += added;
2838                         dels += deleted;
2839                 }
2840         }
2841         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2842 }
2843
2844 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2845 {
2846         int i;
2847
2848         if (data->nr == 0)
2849                 return;
2850
2851         for (i = 0; i < data->nr; i++) {
2852                 struct diffstat_file *file = data->files[i];
2853
2854                 fprintf(options->file, "%s", diff_line_prefix(options));
2855
2856                 if (file->is_binary)
2857                         fprintf(options->file, "-\t-\t");
2858                 else
2859                         fprintf(options->file,
2860                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2861                                 file->added, file->deleted);
2862                 if (options->line_termination) {
2863                         fill_print_name(file);
2864                         if (!file->is_renamed)
2865                                 write_name_quoted(file->name, options->file,
2866                                                   options->line_termination);
2867                         else {
2868                                 fputs(file->print_name, options->file);
2869                                 putc(options->line_termination, options->file);
2870                         }
2871                 } else {
2872                         if (file->is_renamed) {
2873                                 putc('\0', options->file);
2874                                 write_name_quoted(file->from_name, options->file, '\0');
2875                         }
2876                         write_name_quoted(file->name, options->file, '\0');
2877                 }
2878         }
2879 }
2880
2881 struct dirstat_file {
2882         const char *name;
2883         unsigned long changed;
2884 };
2885
2886 struct dirstat_dir {
2887         struct dirstat_file *files;
2888         int alloc, nr, permille, cumulative;
2889 };
2890
2891 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2892                 unsigned long changed, const char *base, int baselen)
2893 {
2894         unsigned long sum_changes = 0;
2895         unsigned int sources = 0;
2896         const char *line_prefix = diff_line_prefix(opt);
2897
2898         while (dir->nr) {
2899                 struct dirstat_file *f = dir->files;
2900                 int namelen = strlen(f->name);
2901                 unsigned long changes;
2902                 char *slash;
2903
2904                 if (namelen < baselen)
2905                         break;
2906                 if (memcmp(f->name, base, baselen))
2907                         break;
2908                 slash = strchr(f->name + baselen, '/');
2909                 if (slash) {
2910                         int newbaselen = slash + 1 - f->name;
2911                         changes = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2912                         sources++;
2913                 } else {
2914                         changes = f->changed;
2915                         dir->files++;
2916                         dir->nr--;
2917                         sources += 2;
2918                 }
2919                 sum_changes += changes;
2920         }
2921
2922         /*
2923          * We don't report dirstat's for
2924          *  - the top level
2925          *  - or cases where everything came from a single directory
2926          *    under this directory (sources == 1).
2927          */
2928         if (baselen && sources != 1) {
2929                 if (sum_changes) {
2930                         int permille = sum_changes * 1000 / changed;
2931                         if (permille >= dir->permille) {
2932                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2933                                         permille / 10, permille % 10, baselen, base);
2934                                 if (!dir->cumulative)
2935                                         return 0;
2936                         }
2937                 }
2938         }
2939         return sum_changes;
2940 }
2941
2942 static int dirstat_compare(const void *_a, const void *_b)
2943 {
2944         const struct dirstat_file *a = _a;
2945         const struct dirstat_file *b = _b;
2946         return strcmp(a->name, b->name);
2947 }
2948
2949 static void show_dirstat(struct diff_options *options)
2950 {
2951         int i;
2952         unsigned long changed;
2953         struct dirstat_dir dir;
2954         struct diff_queue_struct *q = &diff_queued_diff;
2955
2956         dir.files = NULL;
2957         dir.alloc = 0;
2958         dir.nr = 0;
2959         dir.permille = options->dirstat_permille;
2960         dir.cumulative = options->flags.dirstat_cumulative;
2961
2962         changed = 0;
2963         for (i = 0; i < q->nr; i++) {
2964                 struct diff_filepair *p = q->queue[i];
2965                 const char *name;
2966                 unsigned long copied, added, damage;
2967
2968                 name = p->two->path ? p->two->path : p->one->path;
2969
2970                 if (p->one->oid_valid && p->two->oid_valid &&
2971                     oideq(&p->one->oid, &p->two->oid)) {
2972                         /*
2973                          * The SHA1 has not changed, so pre-/post-content is
2974                          * identical. We can therefore skip looking at the
2975                          * file contents altogether.
2976                          */
2977                         damage = 0;
2978                         goto found_damage;
2979                 }
2980
2981                 if (options->flags.dirstat_by_file) {
2982                         /*
2983                          * In --dirstat-by-file mode, we don't really need to
2984                          * look at the actual file contents at all.
2985                          * The fact that the SHA1 changed is enough for us to
2986                          * add this file to the list of results
2987                          * (with each file contributing equal damage).
2988                          */
2989                         damage = 1;
2990                         goto found_damage;
2991                 }
2992
2993                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2994                         diff_populate_filespec(options->repo, p->one, 0);
2995                         diff_populate_filespec(options->repo, p->two, 0);
2996                         diffcore_count_changes(options->repo,
2997                                                p->one, p->two, NULL, NULL,
2998                                                &copied, &added);
2999                         diff_free_filespec_data(p->one);
3000                         diff_free_filespec_data(p->two);
3001                 } else if (DIFF_FILE_VALID(p->one)) {
3002                         diff_populate_filespec(options->repo, p->one, CHECK_SIZE_ONLY);
3003                         copied = added = 0;
3004                         diff_free_filespec_data(p->one);
3005                 } else if (DIFF_FILE_VALID(p->two)) {
3006                         diff_populate_filespec(options->repo, p->two, CHECK_SIZE_ONLY);
3007                         copied = 0;
3008                         added = p->two->size;
3009                         diff_free_filespec_data(p->two);
3010                 } else
3011                         continue;
3012
3013                 /*
3014                  * Original minus copied is the removed material,
3015                  * added is the new material.  They are both damages
3016                  * made to the preimage.
3017                  * If the resulting damage is zero, we know that
3018                  * diffcore_count_changes() considers the two entries to
3019                  * be identical, but since the oid changed, we
3020                  * know that there must have been _some_ kind of change,
3021                  * so we force all entries to have damage > 0.
3022                  */
3023                 damage = (p->one->size - copied) + added;
3024                 if (!damage)
3025                         damage = 1;
3026
3027 found_damage:
3028                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3029                 dir.files[dir.nr].name = name;
3030                 dir.files[dir.nr].changed = damage;
3031                 changed += damage;
3032                 dir.nr++;
3033         }
3034
3035         /* This can happen even with many files, if everything was renames */
3036         if (!changed)
3037                 return;
3038
3039         /* Show all directories with more than x% of the changes */
3040         QSORT(dir.files, dir.nr, dirstat_compare);
3041         gather_dirstat(options, &dir, changed, "", 0);
3042 }
3043
3044 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
3045 {
3046         int i;
3047         unsigned long changed;
3048         struct dirstat_dir dir;
3049
3050         if (data->nr == 0)
3051                 return;
3052
3053         dir.files = NULL;
3054         dir.alloc = 0;
3055         dir.nr = 0;
3056         dir.permille = options->dirstat_permille;
3057         dir.cumulative = options->flags.dirstat_cumulative;
3058
3059         changed = 0;
3060         for (i = 0; i < data->nr; i++) {
3061                 struct diffstat_file *file = data->files[i];
3062                 unsigned long damage = file->added + file->deleted;
3063                 if (file->is_binary)
3064                         /*
3065                          * binary files counts bytes, not lines. Must find some
3066                          * way to normalize binary bytes vs. textual lines.
3067                          * The following heuristic assumes that there are 64
3068                          * bytes per "line".
3069                          * This is stupid and ugly, but very cheap...
3070                          */
3071                         damage = DIV_ROUND_UP(damage, 64);
3072                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3073                 dir.files[dir.nr].name = file->name;
3074                 dir.files[dir.nr].changed = damage;
3075                 changed += damage;
3076                 dir.nr++;
3077         }
3078
3079         /* This can happen even with many files, if everything was renames */
3080         if (!changed)
3081                 return;
3082
3083         /* Show all directories with more than x% of the changes */
3084         QSORT(dir.files, dir.nr, dirstat_compare);
3085         gather_dirstat(options, &dir, changed, "", 0);
3086 }
3087
3088 static void free_diffstat_info(struct diffstat_t *diffstat)
3089 {
3090         int i;
3091         for (i = 0; i < diffstat->nr; i++) {
3092                 struct diffstat_file *f = diffstat->files[i];
3093                 free(f->print_name);
3094                 free(f->name);
3095                 free(f->from_name);
3096                 free(f);
3097         }
3098         free(diffstat->files);
3099 }
3100
3101 struct checkdiff_t {
3102         const char *filename;
3103         int lineno;
3104         int conflict_marker_size;
3105         struct diff_options *o;
3106         unsigned ws_rule;
3107         unsigned status;
3108 };
3109
3110 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
3111 {
3112         char firstchar;
3113         int cnt;
3114
3115         if (len < marker_size + 1)
3116                 return 0;
3117         firstchar = line[0];
3118         switch (firstchar) {
3119         case '=': case '>': case '<': case '|':
3120                 break;
3121         default:
3122                 return 0;
3123         }
3124         for (cnt = 1; cnt < marker_size; cnt++)
3125                 if (line[cnt] != firstchar)
3126                         return 0;
3127         /* line[1] thru line[marker_size-1] are same as firstchar */
3128         if (len < marker_size + 1 || !isspace(line[marker_size]))
3129                 return 0;
3130         return 1;
3131 }
3132
3133 static void checkdiff_consume(void *priv, char *line, unsigned long len)
3134 {
3135         struct checkdiff_t *data = priv;
3136         int marker_size = data->conflict_marker_size;
3137         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
3138         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
3139         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
3140         char *err;
3141         const char *line_prefix;
3142
3143         assert(data->o);
3144         line_prefix = diff_line_prefix(data->o);
3145
3146         if (line[0] == '+') {
3147                 unsigned bad;
3148                 data->lineno++;
3149                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
3150                         data->status |= 1;
3151                         fprintf(data->o->file,
3152                                 "%s%s:%d: leftover conflict marker\n",
3153                                 line_prefix, data->filename, data->lineno);
3154                 }
3155                 bad = ws_check(line + 1, len - 1, data->ws_rule);
3156                 if (!bad)
3157                         return;
3158                 data->status |= bad;
3159                 err = whitespace_error_string(bad);
3160                 fprintf(data->o->file, "%s%s:%d: %s.\n",
3161                         line_prefix, data->filename, data->lineno, err);
3162                 free(err);
3163                 emit_line(data->o, set, reset, line, 1);
3164                 ws_check_emit(line + 1, len - 1, data->ws_rule,
3165                               data->o->file, set, reset, ws);
3166         } else if (line[0] == ' ') {
3167                 data->lineno++;
3168         } else if (line[0] == '@') {
3169                 char *plus = strchr(line, '+');
3170                 if (plus)
3171                         data->lineno = strtol(plus, NULL, 10) - 1;
3172                 else
3173                         die("invalid diff");
3174         }
3175 }
3176
3177 static unsigned char *deflate_it(char *data,
3178                                  unsigned long size,
3179                                  unsigned long *result_size)
3180 {
3181         int bound;
3182         unsigned char *deflated;
3183         git_zstream stream;
3184
3185         git_deflate_init(&stream, zlib_compression_level);
3186         bound = git_deflate_bound(&stream, size);
3187         deflated = xmalloc(bound);
3188         stream.next_out = deflated;
3189         stream.avail_out = bound;
3190
3191         stream.next_in = (unsigned char *)data;
3192         stream.avail_in = size;
3193         while (git_deflate(&stream, Z_FINISH) == Z_OK)
3194                 ; /* nothing */
3195         git_deflate_end(&stream);
3196         *result_size = stream.total_out;
3197         return deflated;
3198 }
3199
3200 static void emit_binary_diff_body(struct diff_options *o,
3201                                   mmfile_t *one, mmfile_t *two)
3202 {
3203         void *cp;
3204         void *delta;
3205         void *deflated;
3206         void *data;
3207         unsigned long orig_size;
3208         unsigned long delta_size;
3209         unsigned long deflate_size;
3210         unsigned long data_size;
3211
3212         /* We could do deflated delta, or we could do just deflated two,
3213          * whichever is smaller.
3214          */
3215         delta = NULL;
3216         deflated = deflate_it(two->ptr, two->size, &deflate_size);
3217         if (one->size && two->size) {
3218                 delta = diff_delta(one->ptr, one->size,
3219                                    two->ptr, two->size,
3220                                    &delta_size, deflate_size);
3221                 if (delta) {
3222                         void *to_free = delta;
3223                         orig_size = delta_size;
3224                         delta = deflate_it(delta, delta_size, &delta_size);
3225                         free(to_free);
3226                 }
3227         }
3228
3229         if (delta && delta_size < deflate_size) {
3230                 char *s = xstrfmt("%lu", orig_size);
3231                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
3232                                  s, strlen(s), 0);
3233                 free(s);
3234                 free(deflated);
3235                 data = delta;
3236                 data_size = delta_size;
3237         } else {
3238                 char *s = xstrfmt("%lu", two->size);
3239                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
3240                                  s, strlen(s), 0);
3241                 free(s);
3242                 free(delta);
3243                 data = deflated;
3244                 data_size = deflate_size;
3245         }
3246
3247         /* emit data encoded in base85 */
3248         cp = data;
3249         while (data_size) {
3250                 int len;
3251                 int bytes = (52 < data_size) ? 52 : data_size;
3252                 char line[71];
3253                 data_size -= bytes;
3254                 if (bytes <= 26)
3255                         line[0] = bytes + 'A' - 1;
3256                 else
3257                         line[0] = bytes - 26 + 'a' - 1;
3258                 encode_85(line + 1, cp, bytes);
3259                 cp = (char *) cp + bytes;
3260
3261                 len = strlen(line);
3262                 line[len++] = '\n';
3263                 line[len] = '\0';
3264
3265                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
3266                                  line, len, 0);
3267         }
3268         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
3269         free(data);
3270 }
3271
3272 static void emit_binary_diff(struct diff_options *o,
3273                              mmfile_t *one, mmfile_t *two)
3274 {
3275         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
3276         emit_binary_diff_body(o, one, two);
3277         emit_binary_diff_body(o, two, one);
3278 }
3279
3280 int diff_filespec_is_binary(struct repository *r,
3281                             struct diff_filespec *one)
3282 {
3283         if (one->is_binary == -1) {
3284                 diff_filespec_load_driver(one, r->index);
3285                 if (one->driver->binary != -1)
3286                         one->is_binary = one->driver->binary;
3287                 else {
3288                         if (!one->data && DIFF_FILE_VALID(one))
3289                                 diff_populate_filespec(r, one, CHECK_BINARY);
3290                         if (one->is_binary == -1 && one->data)
3291                                 one->is_binary = buffer_is_binary(one->data,
3292                                                 one->size);
3293                         if (one->is_binary == -1)
3294                                 one->is_binary = 0;
3295                 }
3296         }
3297         return one->is_binary;
3298 }
3299
3300 static const struct userdiff_funcname *
3301 diff_funcname_pattern(struct diff_options *o, struct diff_filespec *one)
3302 {
3303         diff_filespec_load_driver(one, o->repo->index);
3304         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3305 }
3306
3307 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3308 {
3309         if (!options->a_prefix)
3310                 options->a_prefix = a;
3311         if (!options->b_prefix)
3312                 options->b_prefix = b;
3313 }
3314
3315 struct userdiff_driver *get_textconv(struct index_state *istate,
3316                                      struct diff_filespec *one)
3317 {
3318         if (!DIFF_FILE_VALID(one))
3319                 return NULL;
3320
3321         diff_filespec_load_driver(one, istate);
3322         return userdiff_get_textconv(one->driver);
3323 }
3324
3325 static void builtin_diff(const char *name_a,
3326                          const char *name_b,
3327                          struct diff_filespec *one,
3328                          struct diff_filespec *two,
3329                          const char *xfrm_msg,
3330                          int must_show_header,
3331                          struct diff_options *o,
3332                          int complete_rewrite)
3333 {
3334         mmfile_t mf1, mf2;
3335         const char *lbl[2];
3336         char *a_one, *b_two;
3337         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3338         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3339         const char *a_prefix, *b_prefix;
3340         struct userdiff_driver *textconv_one = NULL;
3341         struct userdiff_driver *textconv_two = NULL;
3342         struct strbuf header = STRBUF_INIT;
3343         const char *line_prefix = diff_line_prefix(o);
3344
3345         diff_set_mnemonic_prefix(o, "a/", "b/");
3346         if (o->flags.reverse_diff) {
3347                 a_prefix = o->b_prefix;
3348                 b_prefix = o->a_prefix;
3349         } else {
3350                 a_prefix = o->a_prefix;
3351                 b_prefix = o->b_prefix;
3352         }
3353
3354         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3355             (!one->mode || S_ISGITLINK(one->mode)) &&
3356             (!two->mode || S_ISGITLINK(two->mode))) {
3357                 show_submodule_summary(o, one->path ? one->path : two->path,
3358                                 &one->oid, &two->oid,
3359                                 two->dirty_submodule);
3360                 return;
3361         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3362                    (!one->mode || S_ISGITLINK(one->mode)) &&
3363                    (!two->mode || S_ISGITLINK(two->mode))) {
3364                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3365                                 &one->oid, &two->oid,
3366                                 two->dirty_submodule);
3367                 return;
3368         }
3369
3370         if (o->flags.allow_textconv) {
3371                 textconv_one = get_textconv(o->repo->index, one);
3372                 textconv_two = get_textconv(o->repo->index, two);
3373         }
3374
3375         /* Never use a non-valid filename anywhere if at all possible */
3376         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3377         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3378
3379         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3380         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3381         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3382         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3383         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3384         if (lbl[0][0] == '/') {
3385                 /* /dev/null */
3386                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3387                 if (xfrm_msg)
3388                         strbuf_addstr(&header, xfrm_msg);
3389                 must_show_header = 1;
3390         }
3391         else if (lbl[1][0] == '/') {
3392                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3393                 if (xfrm_msg)
3394                         strbuf_addstr(&header, xfrm_msg);
3395                 must_show_header = 1;
3396         }
3397         else {
3398                 if (one->mode != two->mode) {
3399                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3400                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3401                         must_show_header = 1;
3402                 }
3403                 if (xfrm_msg)
3404                         strbuf_addstr(&header, xfrm_msg);
3405
3406                 /*
3407                  * we do not run diff between different kind
3408                  * of objects.
3409                  */
3410                 if ((one->mode ^ two->mode) & S_IFMT)
3411                         goto free_ab_and_return;
3412                 if (complete_rewrite &&
3413                     (textconv_one || !diff_filespec_is_binary(o->repo, one)) &&
3414                     (textconv_two || !diff_filespec_is_binary(o->repo, two))) {
3415                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3416                                          header.buf, header.len, 0);
3417                         strbuf_reset(&header);
3418                         emit_rewrite_diff(name_a, name_b, one, two,
3419                                           textconv_one, textconv_two, o);
3420                         o->found_changes = 1;
3421                         goto free_ab_and_return;
3422                 }
3423         }
3424
3425         if (o->irreversible_delete && lbl[1][0] == '/') {
3426                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3427                                  header.len, 0);
3428                 strbuf_reset(&header);
3429                 goto free_ab_and_return;
3430         } else if (!o->flags.text &&
3431                    ( (!textconv_one && diff_filespec_is_binary(o->repo, one)) ||
3432                      (!textconv_two && diff_filespec_is_binary(o->repo, two)) )) {
3433                 struct strbuf sb = STRBUF_INIT;
3434                 if (!one->data && !two->data &&
3435                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3436                     !o->flags.binary) {
3437                         if (oideq(&one->oid, &two->oid)) {
3438                                 if (must_show_header)
3439                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3440                                                          header.buf, header.len,
3441                                                          0);
3442                                 goto free_ab_and_return;
3443                         }
3444                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3445                                          header.buf, header.len, 0);
3446                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3447                                     diff_line_prefix(o), lbl[0], lbl[1]);
3448                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3449                                          sb.buf, sb.len, 0);
3450                         strbuf_release(&sb);
3451                         goto free_ab_and_return;
3452                 }
3453                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3454                     fill_mmfile(o->repo, &mf2, two) < 0)
3455                         die("unable to read files to diff");
3456                 /* Quite common confusing case */
3457                 if (mf1.size == mf2.size &&
3458                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3459                         if (must_show_header)
3460                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3461                                                  header.buf, header.len, 0);
3462                         goto free_ab_and_return;
3463                 }
3464                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3465                 strbuf_reset(&header);
3466                 if (o->flags.binary)
3467                         emit_binary_diff(o, &mf1, &mf2);
3468                 else {
3469                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3470                                     diff_line_prefix(o), lbl[0], lbl[1]);
3471                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3472                                          sb.buf, sb.len, 0);
3473                         strbuf_release(&sb);
3474                 }
3475                 o->found_changes = 1;
3476         } else {
3477                 /* Crazy xdl interfaces.. */
3478                 const char *diffopts = getenv("GIT_DIFF_OPTS");
3479                 const char *v;
3480                 xpparam_t xpp;
3481                 xdemitconf_t xecfg;
3482                 struct emit_callback ecbdata;
3483                 const struct userdiff_funcname *pe;
3484
3485                 if (must_show_header) {
3486                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3487                                          header.buf, header.len, 0);
3488                         strbuf_reset(&header);
3489                 }
3490
3491                 mf1.size = fill_textconv(o->repo, textconv_one, one, &mf1.ptr);
3492                 mf2.size = fill_textconv(o->repo, textconv_two, two, &mf2.ptr);
3493
3494                 pe = diff_funcname_pattern(o, one);
3495                 if (!pe)
3496                         pe = diff_funcname_pattern(o, two);
3497
3498                 memset(&xpp, 0, sizeof(xpp));
3499                 memset(&xecfg, 0, sizeof(xecfg));
3500                 memset(&ecbdata, 0, sizeof(ecbdata));
3501                 if (o->flags.suppress_diff_headers)
3502                         lbl[0] = NULL;
3503                 ecbdata.label_path = lbl;
3504                 ecbdata.color_diff = want_color(o->use_color);
3505                 ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
3506                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3507                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3508                 ecbdata.opt = o;
3509                 if (header.len && !o->flags.suppress_diff_headers)
3510                         ecbdata.header = &header;
3511                 xpp.flags = o->xdl_opts;
3512                 xpp.anchors = o->anchors;
3513                 xpp.anchors_nr = o->anchors_nr;
3514                 xecfg.ctxlen = o->context;
3515                 xecfg.interhunkctxlen = o->interhunkcontext;
3516                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3517                 if (o->flags.funccontext)
3518                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3519                 if (pe)
3520                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3521                 if (!diffopts)
3522                         ;
3523                 else if (skip_prefix(diffopts, "--unified=", &v))
3524                         xecfg.ctxlen = strtoul(v, NULL, 10);
3525                 else if (skip_prefix(diffopts, "-u", &v))
3526                         xecfg.ctxlen = strtoul(v, NULL, 10);
3527                 if (o->word_diff)
3528                         init_diff_words_data(&ecbdata, o, one, two);
3529                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
3530                                   &xpp, &xecfg))
3531                         die("unable to generate diff for %s", one->path);
3532                 if (o->word_diff)
3533                         free_diff_words_data(&ecbdata);
3534                 if (textconv_one)
3535                         free(mf1.ptr);
3536                 if (textconv_two)
3537                         free(mf2.ptr);
3538                 xdiff_clear_find_func(&xecfg);
3539         }
3540
3541  free_ab_and_return:
3542         strbuf_release(&header);
3543         diff_free_filespec_data(one);
3544         diff_free_filespec_data(two);
3545         free(a_one);
3546         free(b_two);
3547         return;
3548 }
3549
3550 static char *get_compact_summary(const struct diff_filepair *p, int is_renamed)
3551 {
3552         if (!is_renamed) {
3553                 if (p->status == DIFF_STATUS_ADDED) {
3554                         if (S_ISLNK(p->two->mode))
3555                                 return "new +l";
3556                         else if ((p->two->mode & 0777) == 0755)
3557                                 return "new +x";
3558                         else
3559                                 return "new";
3560                 } else if (p->status == DIFF_STATUS_DELETED)
3561                         return "gone";
3562         }
3563         if (S_ISLNK(p->one->mode) && !S_ISLNK(p->two->mode))
3564                 return "mode -l";
3565         else if (!S_ISLNK(p->one->mode) && S_ISLNK(p->two->mode))
3566                 return "mode +l";
3567         else if ((p->one->mode & 0777) == 0644 &&
3568                  (p->two->mode & 0777) == 0755)
3569                 return "mode +x";
3570         else if ((p->one->mode & 0777) == 0755 &&
3571                  (p->two->mode & 0777) == 0644)
3572                 return "mode -x";
3573         return NULL;
3574 }
3575
3576 static void builtin_diffstat(const char *name_a, const char *name_b,
3577                              struct diff_filespec *one,
3578                              struct diff_filespec *two,
3579                              struct diffstat_t *diffstat,
3580                              struct diff_options *o,
3581                              struct diff_filepair *p)
3582 {
3583         mmfile_t mf1, mf2;
3584         struct diffstat_file *data;
3585         int same_contents;
3586         int complete_rewrite = 0;
3587
3588         if (!DIFF_PAIR_UNMERGED(p)) {
3589                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3590                         complete_rewrite = 1;
3591         }
3592
3593         data = diffstat_add(diffstat, name_a, name_b);
3594         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3595         if (o->flags.stat_with_summary)
3596                 data->comments = get_compact_summary(p, data->is_renamed);
3597
3598         if (!one || !two) {
3599                 data->is_unmerged = 1;
3600                 return;
3601         }
3602
3603         same_contents = oideq(&one->oid, &two->oid);
3604
3605         if (diff_filespec_is_binary(o->repo, one) ||
3606             diff_filespec_is_binary(o->repo, two)) {
3607                 data->is_binary = 1;
3608                 if (same_contents) {
3609                         data->added = 0;
3610                         data->deleted = 0;
3611                 } else {
3612                         data->added = diff_filespec_size(o->repo, two);
3613                         data->deleted = diff_filespec_size(o->repo, one);
3614                 }
3615         }
3616
3617         else if (complete_rewrite) {
3618                 diff_populate_filespec(o->repo, one, 0);
3619                 diff_populate_filespec(o->repo, two, 0);
3620                 data->deleted = count_lines(one->data, one->size);
3621                 data->added = count_lines(two->data, two->size);
3622         }
3623
3624         else if (!same_contents) {
3625                 /* Crazy xdl interfaces.. */
3626                 xpparam_t xpp;
3627                 xdemitconf_t xecfg;
3628
3629                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3630                     fill_mmfile(o->repo, &mf2, two) < 0)
3631                         die("unable to read files to diff");
3632
3633                 memset(&xpp, 0, sizeof(xpp));
3634                 memset(&xecfg, 0, sizeof(xecfg));
3635                 xpp.flags = o->xdl_opts;
3636                 xpp.anchors = o->anchors;
3637                 xpp.anchors_nr = o->anchors_nr;
3638                 xecfg.ctxlen = o->context;
3639                 xecfg.interhunkctxlen = o->interhunkcontext;
3640                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
3641                                   &xpp, &xecfg))
3642                         die("unable to generate diffstat for %s", one->path);
3643         }
3644
3645         diff_free_filespec_data(one);
3646         diff_free_filespec_data(two);
3647 }
3648
3649 static void builtin_checkdiff(const char *name_a, const char *name_b,
3650                               const char *attr_path,
3651                               struct diff_filespec *one,
3652                               struct diff_filespec *two,
3653                               struct diff_options *o)
3654 {
3655         mmfile_t mf1, mf2;
3656         struct checkdiff_t data;
3657
3658         if (!two)
3659                 return;
3660
3661         memset(&data, 0, sizeof(data));
3662         data.filename = name_b ? name_b : name_a;
3663         data.lineno = 0;
3664         data.o = o;
3665         data.ws_rule = whitespace_rule(o->repo->index, attr_path);
3666         data.conflict_marker_size = ll_merge_marker_size(o->repo->index, attr_path);
3667
3668         if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3669             fill_mmfile(o->repo, &mf2, two) < 0)
3670                 die("unable to read files to diff");
3671
3672         /*
3673          * All the other codepaths check both sides, but not checking
3674          * the "old" side here is deliberate.  We are checking the newly
3675          * introduced changes, and as long as the "new" side is text, we
3676          * can and should check what it introduces.
3677          */
3678         if (diff_filespec_is_binary(o->repo, two))
3679                 goto free_and_return;
3680         else {
3681                 /* Crazy xdl interfaces.. */
3682                 xpparam_t xpp;
3683                 xdemitconf_t xecfg;
3684
3685                 memset(&xpp, 0, sizeof(xpp));
3686                 memset(&xecfg, 0, sizeof(xecfg));
3687                 xecfg.ctxlen = 1; /* at least one context line */
3688                 xpp.flags = 0;
3689                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
3690                                   &xpp, &xecfg))
3691                         die("unable to generate checkdiff for %s", one->path);
3692
3693                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3694                         struct emit_callback ecbdata;
3695                         int blank_at_eof;
3696
3697                         ecbdata.ws_rule = data.ws_rule;
3698                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3699                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3700
3701                         if (blank_at_eof) {
3702                                 static char *err;
3703                                 if (!err)
3704                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3705                                 fprintf(o->file, "%s:%d: %s.\n",
3706                                         data.filename, blank_at_eof, err);
3707                                 data.status = 1; /* report errors */
3708                         }
3709                 }
3710         }
3711  free_and_return:
3712         diff_free_filespec_data(one);
3713         diff_free_filespec_data(two);
3714         if (data.status)
3715                 o->flags.check_failed = 1;
3716 }
3717
3718 struct diff_filespec *alloc_filespec(const char *path)
3719 {
3720         struct diff_filespec *spec;
3721
3722         FLEXPTR_ALLOC_STR(spec, path, path);
3723         spec->count = 1;
3724         spec->is_binary = -1;
3725         return spec;
3726 }
3727
3728 void free_filespec(struct diff_filespec *spec)
3729 {
3730         if (!--spec->count) {
3731                 diff_free_filespec_data(spec);
3732                 free(spec);
3733         }
3734 }
3735
3736 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3737                    int oid_valid, unsigned short mode)
3738 {
3739         if (mode) {
3740                 spec->mode = canon_mode(mode);
3741                 oidcpy(&spec->oid, oid);
3742                 spec->oid_valid = oid_valid;
3743         }
3744 }
3745
3746 /*
3747  * Given a name and sha1 pair, if the index tells us the file in
3748  * the work tree has that object contents, return true, so that
3749  * prepare_temp_file() does not have to inflate and extract.
3750  */
3751 static int reuse_worktree_file(struct index_state *istate,
3752                                const char *name,
3753                                const struct object_id *oid,
3754                                int want_file)
3755 {
3756         const struct cache_entry *ce;
3757         struct stat st;
3758         int pos, len;
3759
3760         /*
3761          * We do not read the cache ourselves here, because the
3762          * benchmark with my previous version that always reads cache
3763          * shows that it makes things worse for diff-tree comparing
3764          * two linux-2.6 kernel trees in an already checked out work
3765          * tree.  This is because most diff-tree comparisons deal with
3766          * only a small number of files, while reading the cache is
3767          * expensive for a large project, and its cost outweighs the
3768          * savings we get by not inflating the object to a temporary
3769          * file.  Practically, this code only helps when we are used
3770          * by diff-cache --cached, which does read the cache before
3771          * calling us.
3772          */
3773         if (!istate->cache)
3774                 return 0;
3775
3776         /* We want to avoid the working directory if our caller
3777          * doesn't need the data in a normal file, this system
3778          * is rather slow with its stat/open/mmap/close syscalls,
3779          * and the object is contained in a pack file.  The pack
3780          * is probably already open and will be faster to obtain
3781          * the data through than the working directory.  Loose
3782          * objects however would tend to be slower as they need
3783          * to be individually opened and inflated.
3784          */
3785         if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
3786                 return 0;
3787
3788         /*
3789          * Similarly, if we'd have to convert the file contents anyway, that
3790          * makes the optimization not worthwhile.
3791          */
3792         if (!want_file && would_convert_to_git(istate, name))
3793                 return 0;
3794
3795         len = strlen(name);
3796         pos = index_name_pos(istate, name, len);
3797         if (pos < 0)
3798                 return 0;
3799         ce = istate->cache[pos];
3800
3801         /*
3802          * This is not the sha1 we are looking for, or
3803          * unreusable because it is not a regular file.
3804          */
3805         if (!oideq(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3806                 return 0;
3807
3808         /*
3809          * If ce is marked as "assume unchanged", there is no
3810          * guarantee that work tree matches what we are looking for.
3811          */
3812         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3813                 return 0;
3814
3815         /*
3816          * If ce matches the file in the work tree, we can reuse it.
3817          */
3818         if (ce_uptodate(ce) ||
3819             (!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0)))
3820                 return 1;
3821
3822         return 0;
3823 }
3824
3825 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3826 {
3827         struct strbuf buf = STRBUF_INIT;
3828         char *dirty = "";
3829
3830         /* Are we looking at the work tree? */
3831         if (s->dirty_submodule)
3832                 dirty = "-dirty";
3833
3834         strbuf_addf(&buf, "Subproject commit %s%s\n",
3835                     oid_to_hex(&s->oid), dirty);
3836         s->size = buf.len;
3837         if (size_only) {
3838                 s->data = NULL;
3839                 strbuf_release(&buf);
3840         } else {
3841                 s->data = strbuf_detach(&buf, NULL);
3842                 s->should_free = 1;
3843         }
3844         return 0;
3845 }
3846
3847 /*
3848  * While doing rename detection and pickaxe operation, we may need to
3849  * grab the data for the blob (or file) for our own in-core comparison.
3850  * diff_filespec has data and size fields for this purpose.
3851  */
3852 int diff_populate_filespec(struct repository *r,
3853                            struct diff_filespec *s,
3854                            unsigned int flags)
3855 {
3856         int size_only = flags & CHECK_SIZE_ONLY;
3857         int err = 0;
3858         int conv_flags = global_conv_flags_eol;
3859         /*
3860          * demote FAIL to WARN to allow inspecting the situation
3861          * instead of refusing.
3862          */
3863         if (conv_flags & CONV_EOL_RNDTRP_DIE)
3864                 conv_flags = CONV_EOL_RNDTRP_WARN;
3865
3866         if (!DIFF_FILE_VALID(s))
3867                 die("internal error: asking to populate invalid file.");
3868         if (S_ISDIR(s->mode))
3869                 return -1;
3870
3871         if (s->data)
3872                 return 0;
3873
3874         if (size_only && 0 < s->size)
3875                 return 0;
3876
3877         if (S_ISGITLINK(s->mode))
3878                 return diff_populate_gitlink(s, size_only);
3879
3880         if (!s->oid_valid ||
3881             reuse_worktree_file(r->index, s->path, &s->oid, 0)) {
3882                 struct strbuf buf = STRBUF_INIT;
3883                 struct stat st;
3884                 int fd;
3885
3886                 if (lstat(s->path, &st) < 0) {
3887                 err_empty:
3888                         err = -1;
3889                 empty:
3890                         s->data = (char *)"";
3891                         s->size = 0;
3892                         return err;
3893                 }
3894                 s->size = xsize_t(st.st_size);
3895                 if (!s->size)
3896                         goto empty;
3897                 if (S_ISLNK(st.st_mode)) {
3898                         struct strbuf sb = STRBUF_INIT;
3899
3900                         if (strbuf_readlink(&sb, s->path, s->size))
3901                                 goto err_empty;
3902                         s->size = sb.len;
3903                         s->data = strbuf_detach(&sb, NULL);
3904                         s->should_free = 1;
3905                         return 0;
3906                 }
3907
3908                 /*
3909                  * Even if the caller would be happy with getting
3910                  * only the size, we cannot return early at this
3911                  * point if the path requires us to run the content
3912                  * conversion.
3913                  */
3914                 if (size_only && !would_convert_to_git(r->index, s->path))
3915                         return 0;
3916
3917                 /*
3918                  * Note: this check uses xsize_t(st.st_size) that may
3919                  * not be the true size of the blob after it goes
3920                  * through convert_to_git().  This may not strictly be
3921                  * correct, but the whole point of big_file_threshold
3922                  * and is_binary check being that we want to avoid
3923                  * opening the file and inspecting the contents, this
3924                  * is probably fine.
3925                  */
3926                 if ((flags & CHECK_BINARY) &&
3927                     s->size > big_file_threshold && s->is_binary == -1) {
3928                         s->is_binary = 1;
3929                         return 0;
3930                 }
3931                 fd = open(s->path, O_RDONLY);
3932                 if (fd < 0)
3933                         goto err_empty;
3934                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3935                 close(fd);
3936                 s->should_munmap = 1;
3937
3938                 /*
3939                  * Convert from working tree format to canonical git format
3940                  */
3941                 if (convert_to_git(r->index, s->path, s->data, s->size, &buf, conv_flags)) {
3942                         size_t size = 0;
3943                         munmap(s->data, s->size);
3944                         s->should_munmap = 0;
3945                         s->data = strbuf_detach(&buf, &size);
3946                         s->size = size;
3947                         s->should_free = 1;
3948                 }
3949         }
3950         else {
3951                 enum object_type type;
3952                 if (size_only || (flags & CHECK_BINARY)) {
3953                         type = oid_object_info(r, &s->oid, &s->size);
3954                         if (type < 0)
3955                                 die("unable to read %s",
3956                                     oid_to_hex(&s->oid));
3957                         if (size_only)
3958                                 return 0;
3959                         if (s->size > big_file_threshold && s->is_binary == -1) {
3960                                 s->is_binary = 1;
3961                                 return 0;
3962                         }
3963                 }
3964                 s->data = read_object_file(&s->oid, &type, &s->size);
3965                 if (!s->data)
3966                         die("unable to read %s", oid_to_hex(&s->oid));
3967                 s->should_free = 1;
3968         }
3969         return 0;
3970 }
3971
3972 void diff_free_filespec_blob(struct diff_filespec *s)
3973 {
3974         if (s->should_free)
3975                 free(s->data);
3976         else if (s->should_munmap)
3977                 munmap(s->data, s->size);
3978
3979         if (s->should_free || s->should_munmap) {
3980                 s->should_free = s->should_munmap = 0;
3981                 s->data = NULL;
3982         }
3983 }
3984
3985 void diff_free_filespec_data(struct diff_filespec *s)
3986 {
3987         diff_free_filespec_blob(s);
3988         FREE_AND_NULL(s->cnt_data);
3989 }
3990
3991 static void prep_temp_blob(struct index_state *istate,
3992                            const char *path, struct diff_tempfile *temp,
3993                            void *blob,
3994                            unsigned long size,
3995                            const struct object_id *oid,
3996                            int mode)
3997 {
3998         struct strbuf buf = STRBUF_INIT;
3999         struct strbuf tempfile = STRBUF_INIT;
4000         char *path_dup = xstrdup(path);
4001         const char *base = basename(path_dup);
4002
4003         /* Generate "XXXXXX_basename.ext" */
4004         strbuf_addstr(&tempfile, "XXXXXX_");
4005         strbuf_addstr(&tempfile, base);
4006
4007         temp->tempfile = mks_tempfile_ts(tempfile.buf, strlen(base) + 1);
4008         if (!temp->tempfile)
4009                 die_errno("unable to create temp-file");
4010         if (convert_to_working_tree(istate, path,
4011                         (const char *)blob, (size_t)size, &buf)) {
4012                 blob = buf.buf;
4013                 size = buf.len;
4014         }
4015         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
4016             close_tempfile_gently(temp->tempfile))
4017                 die_errno("unable to write temp-file");
4018         temp->name = get_tempfile_path(temp->tempfile);
4019         oid_to_hex_r(temp->hex, oid);
4020         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
4021         strbuf_release(&buf);
4022         strbuf_release(&tempfile);
4023         free(path_dup);
4024 }
4025
4026 static struct diff_tempfile *prepare_temp_file(struct repository *r,
4027                                                const char *name,
4028                                                struct diff_filespec *one)
4029 {
4030         struct diff_tempfile *temp = claim_diff_tempfile();
4031
4032         if (!DIFF_FILE_VALID(one)) {
4033         not_a_valid_file:
4034                 /* A '-' entry produces this for file-2, and
4035                  * a '+' entry produces this for file-1.
4036                  */
4037                 temp->name = "/dev/null";
4038                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
4039                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
4040                 return temp;
4041         }
4042
4043         if (!S_ISGITLINK(one->mode) &&
4044             (!one->oid_valid ||
4045              reuse_worktree_file(r->index, name, &one->oid, 1))) {
4046                 struct stat st;
4047                 if (lstat(name, &st) < 0) {
4048                         if (errno == ENOENT)
4049                                 goto not_a_valid_file;
4050                         die_errno("stat(%s)", name);
4051                 }
4052                 if (S_ISLNK(st.st_mode)) {
4053                         struct strbuf sb = STRBUF_INIT;
4054                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
4055                                 die_errno("readlink(%s)", name);
4056                         prep_temp_blob(r->index, name, temp, sb.buf, sb.len,
4057                                        (one->oid_valid ?
4058                                         &one->oid : &null_oid),
4059                                        (one->oid_valid ?
4060                                         one->mode : S_IFLNK));
4061                         strbuf_release(&sb);
4062                 }
4063                 else {
4064                         /* we can borrow from the file in the work tree */
4065                         temp->name = name;
4066                         if (!one->oid_valid)
4067                                 oid_to_hex_r(temp->hex, &null_oid);
4068                         else
4069                                 oid_to_hex_r(temp->hex, &one->oid);
4070                         /* Even though we may sometimes borrow the
4071                          * contents from the work tree, we always want
4072                          * one->mode.  mode is trustworthy even when
4073                          * !(one->oid_valid), as long as
4074                          * DIFF_FILE_VALID(one).
4075                          */
4076                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
4077                 }
4078                 return temp;
4079         }
4080         else {
4081                 if (diff_populate_filespec(r, one, 0))
4082                         die("cannot read data blob for %s", one->path);
4083                 prep_temp_blob(r->index, name, temp,
4084                                one->data, one->size,
4085                                &one->oid, one->mode);
4086         }
4087         return temp;
4088 }
4089
4090 static void add_external_diff_name(struct repository *r,
4091                                    struct argv_array *argv,
4092                                    const char *name,
4093                                    struct diff_filespec *df)
4094 {
4095         struct diff_tempfile *temp = prepare_temp_file(r, name, df);
4096         argv_array_push(argv, temp->name);
4097         argv_array_push(argv, temp->hex);
4098         argv_array_push(argv, temp->mode);
4099 }
4100
4101 /* An external diff command takes:
4102  *
4103  * diff-cmd name infile1 infile1-sha1 infile1-mode \
4104  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
4105  *
4106  */
4107 static void run_external_diff(const char *pgm,
4108                               const char *name,
4109                               const char *other,
4110                               struct diff_filespec *one,
4111                               struct diff_filespec *two,
4112                               const char *xfrm_msg,
4113                               int complete_rewrite,
4114                               struct diff_options *o)
4115 {
4116         struct argv_array argv = ARGV_ARRAY_INIT;
4117         struct argv_array env = ARGV_ARRAY_INIT;
4118         struct diff_queue_struct *q = &diff_queued_diff;
4119
4120         argv_array_push(&argv, pgm);
4121         argv_array_push(&argv, name);
4122
4123         if (one && two) {
4124                 add_external_diff_name(o->repo, &argv, name, one);
4125                 if (!other)
4126                         add_external_diff_name(o->repo, &argv, name, two);
4127                 else {
4128                         add_external_diff_name(o->repo, &argv, other, two);
4129                         argv_array_push(&argv, other);
4130                         argv_array_push(&argv, xfrm_msg);
4131                 }
4132         }
4133
4134         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
4135         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
4136
4137         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
4138                 die(_("external diff died, stopping at %s"), name);
4139
4140         remove_tempfile();
4141         argv_array_clear(&argv);
4142         argv_array_clear(&env);
4143 }
4144
4145 static int similarity_index(struct diff_filepair *p)
4146 {
4147         return p->score * 100 / MAX_SCORE;
4148 }
4149
4150 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
4151 {
4152         if (startup_info->have_repository)
4153                 return find_unique_abbrev(oid, abbrev);
4154         else {
4155                 char *hex = oid_to_hex(oid);
4156                 if (abbrev < 0)
4157                         abbrev = FALLBACK_DEFAULT_ABBREV;
4158                 if (abbrev > the_hash_algo->hexsz)
4159                         BUG("oid abbreviation out of range: %d", abbrev);
4160                 if (abbrev)
4161                         hex[abbrev] = '\0';
4162                 return hex;
4163         }
4164 }
4165
4166 static void fill_metainfo(struct strbuf *msg,
4167                           const char *name,
4168                           const char *other,
4169                           struct diff_filespec *one,
4170                           struct diff_filespec *two,
4171                           struct diff_options *o,
4172                           struct diff_filepair *p,
4173                           int *must_show_header,
4174                           int use_color)
4175 {
4176         const char *set = diff_get_color(use_color, DIFF_METAINFO);
4177         const char *reset = diff_get_color(use_color, DIFF_RESET);
4178         const char *line_prefix = diff_line_prefix(o);
4179
4180         *must_show_header = 1;
4181         strbuf_init(msg, PATH_MAX * 2 + 300);
4182         switch (p->status) {
4183         case DIFF_STATUS_COPIED:
4184                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4185                             line_prefix, set, similarity_index(p));
4186                 strbuf_addf(msg, "%s\n%s%scopy from ",
4187                             reset,  line_prefix, set);
4188                 quote_c_style(name, msg, NULL, 0);
4189                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
4190                 quote_c_style(other, msg, NULL, 0);
4191                 strbuf_addf(msg, "%s\n", reset);
4192                 break;
4193         case DIFF_STATUS_RENAMED:
4194                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4195                             line_prefix, set, similarity_index(p));
4196                 strbuf_addf(msg, "%s\n%s%srename from ",
4197                             reset, line_prefix, set);
4198                 quote_c_style(name, msg, NULL, 0);
4199                 strbuf_addf(msg, "%s\n%s%srename to ",
4200                             reset, line_prefix, set);
4201                 quote_c_style(other, msg, NULL, 0);
4202                 strbuf_addf(msg, "%s\n", reset);
4203                 break;
4204         case DIFF_STATUS_MODIFIED:
4205                 if (p->score) {
4206                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
4207                                     line_prefix,
4208                                     set, similarity_index(p), reset);
4209                         break;
4210                 }
4211                 /* fallthru */
4212         default:
4213                 *must_show_header = 0;
4214         }
4215         if (one && two && !oideq(&one->oid, &two->oid)) {
4216                 const unsigned hexsz = the_hash_algo->hexsz;
4217                 int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
4218
4219                 if (o->flags.binary) {
4220                         mmfile_t mf;
4221                         if ((!fill_mmfile(o->repo, &mf, one) &&
4222                              diff_filespec_is_binary(o->repo, one)) ||
4223                             (!fill_mmfile(o->repo, &mf, two) &&
4224                              diff_filespec_is_binary(o->repo, two)))
4225                                 abbrev = hexsz;
4226                 }
4227                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
4228                             diff_abbrev_oid(&one->oid, abbrev),
4229                             diff_abbrev_oid(&two->oid, abbrev));
4230                 if (one->mode == two->mode)
4231                         strbuf_addf(msg, " %06o", one->mode);
4232                 strbuf_addf(msg, "%s\n", reset);
4233         }
4234 }
4235
4236 static void run_diff_cmd(const char *pgm,
4237                          const char *name,
4238                          const char *other,
4239                          const char *attr_path,
4240                          struct diff_filespec *one,
4241                          struct diff_filespec *two,
4242                          struct strbuf *msg,
4243                          struct diff_options *o,
4244                          struct diff_filepair *p)
4245 {
4246         const char *xfrm_msg = NULL;
4247         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
4248         int must_show_header = 0;
4249
4250
4251         if (o->flags.allow_external) {
4252                 struct userdiff_driver *drv;
4253
4254                 drv = userdiff_find_by_path(o->repo->index, attr_path);
4255                 if (drv && drv->external)
4256                         pgm = drv->external;
4257         }
4258
4259         if (msg) {
4260                 /*
4261                  * don't use colors when the header is intended for an
4262                  * external diff driver
4263                  */
4264                 fill_metainfo(msg, name, other, one, two, o, p,
4265                               &must_show_header,
4266                               want_color(o->use_color) && !pgm);
4267                 xfrm_msg = msg->len ? msg->buf : NULL;
4268         }
4269
4270         if (pgm) {
4271                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
4272                                   complete_rewrite, o);
4273                 return;
4274         }
4275         if (one && two)
4276                 builtin_diff(name, other ? other : name,
4277                              one, two, xfrm_msg, must_show_header,
4278                              o, complete_rewrite);
4279         else
4280                 fprintf(o->file, "* Unmerged path %s\n", name);
4281 }
4282
4283 static void diff_fill_oid_info(struct diff_filespec *one, struct index_state *istate)
4284 {
4285         if (DIFF_FILE_VALID(one)) {
4286                 if (!one->oid_valid) {
4287                         struct stat st;
4288                         if (one->is_stdin) {
4289                                 oidclr(&one->oid);
4290                                 return;
4291                         }
4292                         if (lstat(one->path, &st) < 0)
4293                                 die_errno("stat '%s'", one->path);
4294                         if (index_path(istate, &one->oid, one->path, &st, 0))
4295                                 die("cannot hash %s", one->path);
4296                 }
4297         }
4298         else
4299                 oidclr(&one->oid);
4300 }
4301
4302 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
4303 {
4304         /* Strip the prefix but do not molest /dev/null and absolute paths */
4305         if (*namep && !is_absolute_path(*namep)) {
4306                 *namep += prefix_length;
4307                 if (**namep == '/')
4308                         ++*namep;
4309         }
4310         if (*otherp && !is_absolute_path(*otherp)) {
4311                 *otherp += prefix_length;
4312                 if (**otherp == '/')
4313                         ++*otherp;
4314         }
4315 }
4316
4317 static void run_diff(struct diff_filepair *p, struct diff_options *o)
4318 {
4319         const char *pgm = external_diff();
4320         struct strbuf msg;
4321         struct diff_filespec *one = p->one;
4322         struct diff_filespec *two = p->two;
4323         const char *name;
4324         const char *other;
4325         const char *attr_path;
4326
4327         name  = one->path;
4328         other = (strcmp(name, two->path) ? two->path : NULL);
4329         attr_path = name;
4330         if (o->prefix_length)
4331                 strip_prefix(o->prefix_length, &name, &other);
4332
4333         if (!o->flags.allow_external)
4334                 pgm = NULL;
4335
4336         if (DIFF_PAIR_UNMERGED(p)) {
4337                 run_diff_cmd(pgm, name, NULL, attr_path,
4338                              NULL, NULL, NULL, o, p);
4339                 return;
4340         }
4341
4342         diff_fill_oid_info(one, o->repo->index);
4343         diff_fill_oid_info(two, o->repo->index);
4344
4345         if (!pgm &&
4346             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4347             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4348                 /*
4349                  * a filepair that changes between file and symlink
4350                  * needs to be split into deletion and creation.
4351                  */
4352                 struct diff_filespec *null = alloc_filespec(two->path);
4353                 run_diff_cmd(NULL, name, other, attr_path,
4354                              one, null, &msg,
4355                              o, p);
4356                 free(null);
4357                 strbuf_release(&msg);
4358
4359                 null = alloc_filespec(one->path);
4360                 run_diff_cmd(NULL, name, other, attr_path,
4361                              null, two, &msg, o, p);
4362                 free(null);
4363         }
4364         else
4365                 run_diff_cmd(pgm, name, other, attr_path,
4366                              one, two, &msg, o, p);
4367
4368         strbuf_release(&msg);
4369 }
4370
4371 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4372                          struct diffstat_t *diffstat)
4373 {
4374         const char *name;
4375         const char *other;
4376
4377         if (DIFF_PAIR_UNMERGED(p)) {
4378                 /* unmerged */
4379                 builtin_diffstat(p->one->path, NULL, NULL, NULL,
4380                                  diffstat, o, p);
4381                 return;
4382         }
4383
4384         name = p->one->path;
4385         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4386
4387         if (o->prefix_length)
4388                 strip_prefix(o->prefix_length, &name, &other);
4389
4390         diff_fill_oid_info(p->one, o->repo->index);
4391         diff_fill_oid_info(p->two, o->repo->index);
4392
4393         builtin_diffstat(name, other, p->one, p->two,
4394                          diffstat, o, p);
4395 }
4396
4397 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4398 {
4399         const char *name;
4400         const char *other;
4401         const char *attr_path;
4402
4403         if (DIFF_PAIR_UNMERGED(p)) {
4404                 /* unmerged */
4405                 return;
4406         }
4407
4408         name = p->one->path;
4409         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4410         attr_path = other ? other : name;
4411
4412         if (o->prefix_length)
4413                 strip_prefix(o->prefix_length, &name, &other);
4414
4415         diff_fill_oid_info(p->one, o->repo->index);
4416         diff_fill_oid_info(p->two, o->repo->index);
4417
4418         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4419 }
4420
4421 void repo_diff_setup(struct repository *r, struct diff_options *options)
4422 {
4423         memcpy(options, &default_diff_options, sizeof(*options));
4424
4425         options->file = stdout;
4426         options->repo = r;
4427
4428         options->output_indicators[OUTPUT_INDICATOR_NEW] = '+';
4429         options->output_indicators[OUTPUT_INDICATOR_OLD] = '-';
4430         options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = ' ';
4431         options->abbrev = DEFAULT_ABBREV;
4432         options->line_termination = '\n';
4433         options->break_opt = -1;
4434         options->rename_limit = -1;
4435         options->dirstat_permille = diff_dirstat_permille_default;
4436         options->context = diff_context_default;
4437         options->interhunkcontext = diff_interhunk_context_default;
4438         options->ws_error_highlight = ws_error_highlight_default;
4439         options->flags.rename_empty = 1;
4440         options->objfind = NULL;
4441
4442         /* pathchange left =NULL by default */
4443         options->change = diff_change;
4444         options->add_remove = diff_addremove;
4445         options->use_color = diff_use_color_default;
4446         options->detect_rename = diff_detect_rename_default;
4447         options->xdl_opts |= diff_algorithm;
4448         if (diff_indent_heuristic)
4449                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4450
4451         options->orderfile = diff_order_file_cfg;
4452
4453         if (diff_no_prefix) {
4454                 options->a_prefix = options->b_prefix = "";
4455         } else if (!diff_mnemonic_prefix) {
4456                 options->a_prefix = "a/";
4457                 options->b_prefix = "b/";
4458         }
4459
4460         options->color_moved = diff_color_moved_default;
4461         options->color_moved_ws_handling = diff_color_moved_ws_default;
4462 }
4463
4464 void diff_setup_done(struct diff_options *options)
4465 {
4466         unsigned check_mask = DIFF_FORMAT_NAME |
4467                               DIFF_FORMAT_NAME_STATUS |
4468                               DIFF_FORMAT_CHECKDIFF |
4469                               DIFF_FORMAT_NO_OUTPUT;
4470         /*
4471          * This must be signed because we're comparing against a potentially
4472          * negative value.
4473          */
4474         const int hexsz = the_hash_algo->hexsz;
4475
4476         if (options->set_default)
4477                 options->set_default(options);
4478
4479         if (HAS_MULTI_BITS(options->output_format & check_mask))
4480                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4481
4482         if (HAS_MULTI_BITS(options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
4483                 die(_("-G, -S and --find-object are mutually exclusive"));
4484
4485         /*
4486          * Most of the time we can say "there are changes"
4487          * only by checking if there are changed paths, but
4488          * --ignore-whitespace* options force us to look
4489          * inside contents.
4490          */
4491
4492         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4493                 options->flags.diff_from_contents = 1;
4494         else
4495                 options->flags.diff_from_contents = 0;
4496
4497         if (options->flags.find_copies_harder)
4498                 options->detect_rename = DIFF_DETECT_COPY;
4499
4500         if (!options->flags.relative_name)
4501                 options->prefix = NULL;
4502         if (options->prefix)
4503                 options->prefix_length = strlen(options->prefix);
4504         else
4505                 options->prefix_length = 0;
4506
4507         if (options->output_format & (DIFF_FORMAT_NAME |
4508                                       DIFF_FORMAT_NAME_STATUS |
4509                                       DIFF_FORMAT_CHECKDIFF |
4510                                       DIFF_FORMAT_NO_OUTPUT))
4511                 options->output_format &= ~(DIFF_FORMAT_RAW |
4512                                             DIFF_FORMAT_NUMSTAT |
4513                                             DIFF_FORMAT_DIFFSTAT |
4514                                             DIFF_FORMAT_SHORTSTAT |
4515                                             DIFF_FORMAT_DIRSTAT |
4516                                             DIFF_FORMAT_SUMMARY |
4517                                             DIFF_FORMAT_PATCH);
4518
4519         /*
4520          * These cases always need recursive; we do not drop caller-supplied
4521          * recursive bits for other formats here.
4522          */
4523         if (options->output_format & (DIFF_FORMAT_PATCH |
4524                                       DIFF_FORMAT_NUMSTAT |
4525                                       DIFF_FORMAT_DIFFSTAT |
4526                                       DIFF_FORMAT_SHORTSTAT |
4527                                       DIFF_FORMAT_DIRSTAT |
4528                                       DIFF_FORMAT_SUMMARY |
4529                                       DIFF_FORMAT_CHECKDIFF))
4530                 options->flags.recursive = 1;
4531         /*
4532          * Also pickaxe would not work very well if you do not say recursive
4533          */
4534         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
4535                 options->flags.recursive = 1;
4536         /*
4537          * When patches are generated, submodules diffed against the work tree
4538          * must be checked for dirtiness too so it can be shown in the output
4539          */
4540         if (options->output_format & DIFF_FORMAT_PATCH)
4541                 options->flags.dirty_submodules = 1;
4542
4543         if (options->detect_rename && options->rename_limit < 0)
4544                 options->rename_limit = diff_rename_limit_default;
4545         if (hexsz < options->abbrev)
4546                 options->abbrev = hexsz; /* full */
4547
4548         /*
4549          * It does not make sense to show the first hit we happened
4550          * to have found.  It does not make sense not to return with
4551          * exit code in such a case either.
4552          */
4553         if (options->flags.quick) {
4554                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4555                 options->flags.exit_with_status = 1;
4556         }
4557
4558         options->diff_path_counter = 0;
4559
4560         if (options->flags.follow_renames && options->pathspec.nr != 1)
4561                 die(_("--follow requires exactly one pathspec"));
4562
4563         if (!options->use_color || external_diff())
4564                 options->color_moved = 0;
4565 }
4566
4567 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4568 {
4569         char c, *eq;
4570         int len;
4571
4572         if (*arg != '-')
4573                 return 0;
4574         c = *++arg;
4575         if (!c)
4576                 return 0;
4577         if (c == arg_short) {
4578                 c = *++arg;
4579                 if (!c)
4580                         return 1;
4581                 if (val && isdigit(c)) {
4582                         char *end;
4583                         int n = strtoul(arg, &end, 10);
4584                         if (*end)
4585                                 return 0;
4586                         *val = n;
4587                         return 1;
4588                 }
4589                 return 0;
4590         }
4591         if (c != '-')
4592                 return 0;
4593         arg++;
4594         eq = strchrnul(arg, '=');
4595         len = eq - arg;
4596         if (!len || strncmp(arg, arg_long, len))
4597                 return 0;
4598         if (*eq) {
4599                 int n;
4600                 char *end;
4601                 if (!isdigit(*++eq))
4602                         return 0;
4603                 n = strtoul(eq, &end, 10);
4604                 if (*end)
4605                         return 0;
4606                 *val = n;
4607         }
4608         return 1;
4609 }
4610
4611 static int diff_scoreopt_parse(const char *opt);
4612
4613 static inline int short_opt(char opt, const char **argv,
4614                             const char **optarg)
4615 {
4616         const char *arg = argv[0];
4617         if (arg[0] != '-' || arg[1] != opt)
4618                 return 0;
4619         if (arg[2] != '\0') {
4620                 *optarg = arg + 2;
4621                 return 1;
4622         }
4623         if (!argv[1])
4624                 die("Option '%c' requires a value", opt);
4625         *optarg = argv[1];
4626         return 2;
4627 }
4628
4629 int parse_long_opt(const char *opt, const char **argv,
4630                    const char **optarg)
4631 {
4632         const char *arg = argv[0];
4633         if (!skip_prefix(arg, "--", &arg))
4634                 return 0;
4635         if (!skip_prefix(arg, opt, &arg))
4636                 return 0;
4637         if (*arg == '=') { /* stuck form: --option=value */
4638                 *optarg = arg + 1;
4639                 return 1;
4640         }
4641         if (*arg != '\0')
4642                 return 0;
4643         /* separate form: --option value */
4644         if (!argv[1])
4645                 die("Option '--%s' requires a value", opt);
4646         *optarg = argv[1];
4647         return 2;
4648 }
4649
4650 static int stat_opt(struct diff_options *options, const char **av)
4651 {
4652         const char *arg = av[0];
4653         char *end;
4654         int width = options->stat_width;
4655         int name_width = options->stat_name_width;
4656         int graph_width = options->stat_graph_width;
4657         int count = options->stat_count;
4658         int argcount = 1;
4659
4660         if (!skip_prefix(arg, "--stat", &arg))
4661                 BUG("stat option does not begin with --stat: %s", arg);
4662         end = (char *)arg;
4663
4664         switch (*arg) {
4665         case '-':
4666                 if (skip_prefix(arg, "-width", &arg)) {
4667                         if (*arg == '=')
4668                                 width = strtoul(arg + 1, &end, 10);
4669                         else if (!*arg && !av[1])
4670                                 die_want_option("--stat-width");
4671                         else if (!*arg) {
4672                                 width = strtoul(av[1], &end, 10);
4673                                 argcount = 2;
4674                         }
4675                 } else if (skip_prefix(arg, "-name-width", &arg)) {
4676                         if (*arg == '=')
4677                                 name_width = strtoul(arg + 1, &end, 10);
4678                         else if (!*arg && !av[1])
4679                                 die_want_option("--stat-name-width");
4680                         else if (!*arg) {
4681                                 name_width = strtoul(av[1], &end, 10);
4682                                 argcount = 2;
4683                         }
4684                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
4685                         if (*arg == '=')
4686                                 graph_width = strtoul(arg + 1, &end, 10);
4687                         else if (!*arg && !av[1])
4688                                 die_want_option("--stat-graph-width");
4689                         else if (!*arg) {
4690                                 graph_width = strtoul(av[1], &end, 10);
4691                                 argcount = 2;
4692                         }
4693                 } else if (skip_prefix(arg, "-count", &arg)) {
4694                         if (*arg == '=')
4695                                 count = strtoul(arg + 1, &end, 10);
4696                         else if (!*arg && !av[1])
4697                                 die_want_option("--stat-count");
4698                         else if (!*arg) {
4699                                 count = strtoul(av[1], &end, 10);
4700                                 argcount = 2;
4701                         }
4702                 }
4703                 break;
4704         case '=':
4705                 width = strtoul(arg+1, &end, 10);
4706                 if (*end == ',')
4707                         name_width = strtoul(end+1, &end, 10);
4708                 if (*end == ',')
4709                         count = strtoul(end+1, &end, 10);
4710         }
4711
4712         /* Important! This checks all the error cases! */
4713         if (*end)
4714                 return 0;
4715         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4716         options->stat_name_width = name_width;
4717         options->stat_graph_width = graph_width;
4718         options->stat_width = width;
4719         options->stat_count = count;
4720         return argcount;
4721 }
4722
4723 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4724 {
4725         struct strbuf errmsg = STRBUF_INIT;
4726         if (parse_dirstat_params(options, params, &errmsg))
4727                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4728                     errmsg.buf);
4729         strbuf_release(&errmsg);
4730         /*
4731          * The caller knows a dirstat-related option is given from the command
4732          * line; allow it to say "return this_function();"
4733          */
4734         options->output_format |= DIFF_FORMAT_DIRSTAT;
4735         return 1;
4736 }
4737
4738 static int parse_submodule_opt(struct diff_options *options, const char *value)
4739 {
4740         if (parse_submodule_params(options, value))
4741                 die(_("Failed to parse --submodule option parameter: '%s'"),
4742                         value);
4743         return 1;
4744 }
4745
4746 static const char diff_status_letters[] = {
4747         DIFF_STATUS_ADDED,
4748         DIFF_STATUS_COPIED,
4749         DIFF_STATUS_DELETED,
4750         DIFF_STATUS_MODIFIED,
4751         DIFF_STATUS_RENAMED,
4752         DIFF_STATUS_TYPE_CHANGED,
4753         DIFF_STATUS_UNKNOWN,
4754         DIFF_STATUS_UNMERGED,
4755         DIFF_STATUS_FILTER_AON,
4756         DIFF_STATUS_FILTER_BROKEN,
4757         '\0',
4758 };
4759
4760 static unsigned int filter_bit['Z' + 1];
4761
4762 static void prepare_filter_bits(void)
4763 {
4764         int i;
4765
4766         if (!filter_bit[DIFF_STATUS_ADDED]) {
4767                 for (i = 0; diff_status_letters[i]; i++)
4768                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4769         }
4770 }
4771
4772 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4773 {
4774         return opt->filter & filter_bit[(int) status];
4775 }
4776
4777 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4778 {
4779         int i, optch;
4780
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 optarg[i];
4812                 if (negate)
4813                         opt->filter &= ~bit;
4814                 else
4815                         opt->filter |= bit;
4816         }
4817         return 0;
4818 }
4819
4820 static void enable_patch_output(int *fmt) {
4821         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4822         *fmt |= DIFF_FORMAT_PATCH;
4823 }
4824
4825 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4826 {
4827         int val = parse_ws_error_highlight(arg);
4828
4829         if (val < 0) {
4830                 error("unknown value after ws-error-highlight=%.*s",
4831                       -1 - val, arg);
4832                 return 0;
4833         }
4834         opt->ws_error_highlight = val;
4835         return 1;
4836 }
4837
4838 static int parse_objfind_opt(struct diff_options *opt, const char *arg)
4839 {
4840         struct object_id oid;
4841
4842         if (get_oid(arg, &oid))
4843                 return error("unable to resolve '%s'", arg);
4844
4845         if (!opt->objfind)
4846                 opt->objfind = xcalloc(1, sizeof(*opt->objfind));
4847
4848         opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND;
4849         opt->flags.recursive = 1;
4850         opt->flags.tree_in_recursive = 1;
4851         oidset_insert(opt->objfind, &oid);
4852         return 1;
4853 }
4854
4855 int diff_opt_parse(struct diff_options *options,
4856                    const char **av, int ac, const char *prefix)
4857 {
4858         const char *arg = av[0];
4859         const char *optarg;
4860         int argcount;
4861
4862         if (!prefix)
4863                 prefix = "";
4864
4865         /* Output format options */
4866         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4867             || opt_arg(arg, 'U', "unified", &options->context))
4868                 enable_patch_output(&options->output_format);
4869         else if (!strcmp(arg, "--raw"))
4870                 options->output_format |= DIFF_FORMAT_RAW;
4871         else if (!strcmp(arg, "--patch-with-raw")) {
4872                 enable_patch_output(&options->output_format);
4873                 options->output_format |= DIFF_FORMAT_RAW;
4874         } else if (!strcmp(arg, "--numstat"))
4875                 options->output_format |= DIFF_FORMAT_NUMSTAT;
4876         else if (!strcmp(arg, "--shortstat"))
4877                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
4878         else if (skip_prefix(arg, "-X", &arg) ||
4879                  skip_to_optional_arg(arg, "--dirstat", &arg))
4880                 return parse_dirstat_opt(options, arg);
4881         else if (!strcmp(arg, "--cumulative"))
4882                 return parse_dirstat_opt(options, "cumulative");
4883         else if (skip_to_optional_arg(arg, "--dirstat-by-file", &arg)) {
4884                 parse_dirstat_opt(options, "files");
4885                 return parse_dirstat_opt(options, arg);
4886         }
4887         else if (!strcmp(arg, "--check"))
4888                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
4889         else if (!strcmp(arg, "--summary"))
4890                 options->output_format |= DIFF_FORMAT_SUMMARY;
4891         else if (!strcmp(arg, "--patch-with-stat")) {
4892                 enable_patch_output(&options->output_format);
4893                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
4894         } else if (!strcmp(arg, "--name-only"))
4895                 options->output_format |= DIFF_FORMAT_NAME;
4896         else if (!strcmp(arg, "--name-status"))
4897                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
4898         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4899                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4900         else if (starts_with(arg, "--stat"))
4901                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
4902                 return stat_opt(options, av);
4903         else if (!strcmp(arg, "--compact-summary")) {
4904                  options->flags.stat_with_summary = 1;
4905                  options->output_format |= DIFF_FORMAT_DIFFSTAT;
4906         } else if (!strcmp(arg, "--no-compact-summary"))
4907                  options->flags.stat_with_summary = 0;
4908         else if (skip_prefix(arg, "--output-indicator-new=", &arg))
4909                 options->output_indicators[OUTPUT_INDICATOR_NEW] = arg[0];
4910         else if (skip_prefix(arg, "--output-indicator-old=", &arg))
4911                 options->output_indicators[OUTPUT_INDICATOR_OLD] = arg[0];
4912         else if (skip_prefix(arg, "--output-indicator-context=", &arg))
4913                 options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = arg[0];
4914
4915         /* renames options */
4916         else if (starts_with(arg, "-B") ||
4917                  skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
4918                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4919                         return error("invalid argument to -B: %s", arg+2);
4920         }
4921         else if (starts_with(arg, "-M") ||
4922                  skip_to_optional_arg(arg, "--find-renames", NULL)) {
4923                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4924                         return error("invalid argument to -M: %s", arg+2);
4925                 options->detect_rename = DIFF_DETECT_RENAME;
4926         }
4927         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4928                 options->irreversible_delete = 1;
4929         }
4930         else if (starts_with(arg, "-C") ||
4931                  skip_to_optional_arg(arg, "--find-copies", NULL)) {
4932                 if (options->detect_rename == DIFF_DETECT_COPY)
4933                         options->flags.find_copies_harder = 1;
4934                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4935                         return error("invalid argument to -C: %s", arg+2);
4936                 options->detect_rename = DIFF_DETECT_COPY;
4937         }
4938         else if (!strcmp(arg, "--no-renames"))
4939                 options->detect_rename = 0;
4940         else if (!strcmp(arg, "--rename-empty"))
4941                 options->flags.rename_empty = 1;
4942         else if (!strcmp(arg, "--no-rename-empty"))
4943                 options->flags.rename_empty = 0;
4944         else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
4945                 options->flags.relative_name = 1;
4946                 if (arg)
4947                         options->prefix = arg;
4948         }
4949
4950         /* xdiff options */
4951         else if (!strcmp(arg, "--minimal"))
4952                 DIFF_XDL_SET(options, NEED_MINIMAL);
4953         else if (!strcmp(arg, "--no-minimal"))
4954                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4955         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4956                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4957         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4958                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4959         else if (!strcmp(arg, "--ignore-space-at-eol"))
4960                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4961         else if (!strcmp(arg, "--ignore-cr-at-eol"))
4962                 DIFF_XDL_SET(options, IGNORE_CR_AT_EOL);
4963         else if (!strcmp(arg, "--ignore-blank-lines"))
4964                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4965         else if (!strcmp(arg, "--indent-heuristic"))
4966                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4967         else if (!strcmp(arg, "--no-indent-heuristic"))
4968                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4969         else if (!strcmp(arg, "--patience")) {
4970                 int i;
4971                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4972                 /*
4973                  * Both --patience and --anchored use PATIENCE_DIFF
4974                  * internally, so remove any anchors previously
4975                  * specified.
4976                  */
4977                 for (i = 0; i < options->anchors_nr; i++)
4978                         free(options->anchors[i]);
4979                 options->anchors_nr = 0;
4980         } else if (!strcmp(arg, "--histogram"))
4981                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4982         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4983                 long value = parse_algorithm_value(optarg);
4984                 if (value < 0)
4985                         return error("option diff-algorithm accepts \"myers\", "
4986                                      "\"minimal\", \"patience\" and \"histogram\"");
4987                 /* clear out previous settings */
4988                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4989                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4990                 options->xdl_opts |= value;
4991                 return argcount;
4992         } else if (skip_prefix(arg, "--anchored=", &arg)) {
4993                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4994                 ALLOC_GROW(options->anchors, options->anchors_nr + 1,
4995                            options->anchors_alloc);
4996                 options->anchors[options->anchors_nr++] = xstrdup(arg);
4997         }
4998
4999         /* flags options */
5000         else if (!strcmp(arg, "--binary")) {
5001                 enable_patch_output(&options->output_format);
5002                 options->flags.binary = 1;
5003         }
5004         else if (!strcmp(arg, "--full-index"))
5005                 options->flags.full_index = 1;
5006         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
5007                 options->flags.text = 1;
5008         else if (!strcmp(arg, "-R"))
5009                 options->flags.reverse_diff = 1;
5010         else if (!strcmp(arg, "--find-copies-harder"))
5011                 options->flags.find_copies_harder = 1;
5012         else if (!strcmp(arg, "--follow"))
5013                 options->flags.follow_renames = 1;
5014         else if (!strcmp(arg, "--no-follow")) {
5015                 options->flags.follow_renames = 0;
5016                 options->flags.default_follow_renames = 0;
5017         } else if (skip_to_optional_arg_default(arg, "--color", &arg, "always")) {
5018                 int value = git_config_colorbool(NULL, arg);
5019                 if (value < 0)
5020                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
5021                 options->use_color = value;
5022         }
5023         else if (!strcmp(arg, "--no-color"))
5024                 options->use_color = 0;
5025         else if (!strcmp(arg, "--color-moved")) {
5026                 if (diff_color_moved_default)
5027                         options->color_moved = diff_color_moved_default;
5028                 if (options->color_moved == COLOR_MOVED_NO)
5029                         options->color_moved = COLOR_MOVED_DEFAULT;
5030         } else if (!strcmp(arg, "--no-color-moved"))
5031                 options->color_moved = COLOR_MOVED_NO;
5032         else if (skip_prefix(arg, "--color-moved=", &arg)) {
5033                 int cm = parse_color_moved(arg);
5034                 if (cm < 0)
5035                         die("bad --color-moved argument: %s", arg);
5036                 options->color_moved = cm;
5037         } else if (skip_prefix(arg, "--color-moved-ws=", &arg)) {
5038                 options->color_moved_ws_handling = parse_color_moved_ws(arg);
5039         } else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
5040                 options->use_color = 1;
5041                 options->word_diff = DIFF_WORDS_COLOR;
5042         }
5043         else if (!strcmp(arg, "--word-diff")) {
5044                 if (options->word_diff == DIFF_WORDS_NONE)
5045                         options->word_diff = DIFF_WORDS_PLAIN;
5046         }
5047         else if (skip_prefix(arg, "--word-diff=", &arg)) {
5048                 if (!strcmp(arg, "plain"))
5049                         options->word_diff = DIFF_WORDS_PLAIN;
5050                 else if (!strcmp(arg, "color")) {
5051                         options->use_color = 1;
5052                         options->word_diff = DIFF_WORDS_COLOR;
5053                 }
5054                 else if (!strcmp(arg, "porcelain"))
5055                         options->word_diff = DIFF_WORDS_PORCELAIN;
5056                 else if (!strcmp(arg, "none"))
5057                         options->word_diff = DIFF_WORDS_NONE;
5058                 else
5059                         die("bad --word-diff argument: %s", arg);
5060         }
5061         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
5062                 if (options->word_diff == DIFF_WORDS_NONE)
5063                         options->word_diff = DIFF_WORDS_PLAIN;
5064                 options->word_regex = optarg;
5065                 return argcount;
5066         }
5067         else if (!strcmp(arg, "--exit-code"))
5068                 options->flags.exit_with_status = 1;
5069         else if (!strcmp(arg, "--quiet"))
5070                 options->flags.quick = 1;
5071         else if (!strcmp(arg, "--ext-diff"))
5072                 options->flags.allow_external = 1;
5073         else if (!strcmp(arg, "--no-ext-diff"))
5074                 options->flags.allow_external = 0;
5075         else if (!strcmp(arg, "--textconv")) {
5076                 options->flags.allow_textconv = 1;
5077                 options->flags.textconv_set_via_cmdline = 1;
5078         } else if (!strcmp(arg, "--no-textconv"))
5079                 options->flags.allow_textconv = 0;
5080         else if (skip_to_optional_arg_default(arg, "--ignore-submodules", &arg, "all")) {
5081                 options->flags.override_submodule_config = 1;
5082                 handle_ignore_submodules_arg(options, arg);
5083         } else if (skip_to_optional_arg_default(arg, "--submodule", &arg, "log"))
5084                 return parse_submodule_opt(options, arg);
5085         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
5086                 return parse_ws_error_highlight_opt(options, arg);
5087         else if (!strcmp(arg, "--ita-invisible-in-index"))
5088                 options->ita_invisible_in_index = 1;
5089         else if (!strcmp(arg, "--ita-visible-in-index"))
5090                 options->ita_invisible_in_index = 0;
5091
5092         /* misc options */
5093         else if (!strcmp(arg, "-z"))
5094                 options->line_termination = 0;
5095         else if ((argcount = short_opt('l', av, &optarg))) {
5096                 options->rename_limit = strtoul(optarg, NULL, 10);
5097                 return argcount;
5098         }
5099         else if ((argcount = short_opt('S', av, &optarg))) {
5100                 options->pickaxe = optarg;
5101                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
5102                 return argcount;
5103         } else if ((argcount = short_opt('G', av, &optarg))) {
5104                 options->pickaxe = optarg;
5105                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
5106                 return argcount;
5107         }
5108         else if (!strcmp(arg, "--pickaxe-all"))
5109                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
5110         else if (!strcmp(arg, "--pickaxe-regex"))
5111                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
5112         else if ((argcount = short_opt('O', av, &optarg))) {
5113                 options->orderfile = prefix_filename(prefix, optarg);
5114                 return argcount;
5115         } else if (skip_prefix(arg, "--find-object=", &arg))
5116                 return parse_objfind_opt(options, arg);
5117         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
5118                 int offending = parse_diff_filter_opt(optarg, options);
5119                 if (offending)
5120                         die("unknown change class '%c' in --diff-filter=%s",
5121                             offending, optarg);
5122                 return argcount;
5123         }
5124         else if (!strcmp(arg, "--no-abbrev"))
5125                 options->abbrev = 0;
5126         else if (!strcmp(arg, "--abbrev"))
5127                 options->abbrev = DEFAULT_ABBREV;
5128         else if (skip_prefix(arg, "--abbrev=", &arg)) {
5129                 options->abbrev = strtoul(arg, NULL, 10);
5130                 if (options->abbrev < MINIMUM_ABBREV)
5131                         options->abbrev = MINIMUM_ABBREV;
5132                 else if (the_hash_algo->hexsz < options->abbrev)
5133                         options->abbrev = the_hash_algo->hexsz;
5134         }
5135         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
5136                 options->a_prefix = optarg;
5137                 return argcount;
5138         }
5139         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
5140                 options->line_prefix = optarg;
5141                 options->line_prefix_length = strlen(options->line_prefix);
5142                 graph_setup_line_prefix(options);
5143                 return argcount;
5144         }
5145         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
5146                 options->b_prefix = optarg;
5147                 return argcount;
5148         }
5149         else if (!strcmp(arg, "--no-prefix"))
5150                 options->a_prefix = options->b_prefix = "";
5151         else if (opt_arg(arg, '\0', "inter-hunk-context",
5152                          &options->interhunkcontext))
5153                 ;
5154         else if (!strcmp(arg, "-W"))
5155                 options->flags.funccontext = 1;
5156         else if (!strcmp(arg, "--function-context"))
5157                 options->flags.funccontext = 1;
5158         else if (!strcmp(arg, "--no-function-context"))
5159                 options->flags.funccontext = 0;
5160         else if ((argcount = parse_long_opt("output", av, &optarg))) {
5161                 char *path = prefix_filename(prefix, optarg);
5162                 options->file = xfopen(path, "w");
5163                 options->close_file = 1;
5164                 if (options->use_color != GIT_COLOR_ALWAYS)
5165                         options->use_color = GIT_COLOR_NEVER;
5166                 free(path);
5167                 return argcount;
5168         } else
5169                 return 0;
5170         return 1;
5171 }
5172
5173 int parse_rename_score(const char **cp_p)
5174 {
5175         unsigned long num, scale;
5176         int ch, dot;
5177         const char *cp = *cp_p;
5178
5179         num = 0;
5180         scale = 1;
5181         dot = 0;
5182         for (;;) {
5183                 ch = *cp;
5184                 if ( !dot && ch == '.' ) {
5185                         scale = 1;
5186                         dot = 1;
5187                 } else if ( ch == '%' ) {
5188                         scale = dot ? scale*100 : 100;
5189                         cp++;   /* % is always at the end */
5190                         break;
5191                 } else if ( ch >= '0' && ch <= '9' ) {
5192                         if ( scale < 100000 ) {
5193                                 scale *= 10;
5194                                 num = (num*10) + (ch-'0');
5195                         }
5196                 } else {
5197                         break;
5198                 }
5199                 cp++;
5200         }
5201         *cp_p = cp;
5202
5203         /* user says num divided by scale and we say internally that
5204          * is MAX_SCORE * num / scale.
5205          */
5206         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
5207 }
5208
5209 static int diff_scoreopt_parse(const char *opt)
5210 {
5211         int opt1, opt2, cmd;
5212
5213         if (*opt++ != '-')
5214                 return -1;
5215         cmd = *opt++;
5216         if (cmd == '-') {
5217                 /* convert the long-form arguments into short-form versions */
5218                 if (skip_prefix(opt, "break-rewrites", &opt)) {
5219                         if (*opt == 0 || *opt++ == '=')
5220                                 cmd = 'B';
5221                 } else if (skip_prefix(opt, "find-copies", &opt)) {
5222                         if (*opt == 0 || *opt++ == '=')
5223                                 cmd = 'C';
5224                 } else if (skip_prefix(opt, "find-renames", &opt)) {
5225                         if (*opt == 0 || *opt++ == '=')
5226                                 cmd = 'M';
5227                 }
5228         }
5229         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
5230                 return -1; /* that is not a -M, -C, or -B option */
5231
5232         opt1 = parse_rename_score(&opt);
5233         if (cmd != 'B')
5234                 opt2 = 0;
5235         else {
5236                 if (*opt == 0)
5237                         opt2 = 0;
5238                 else if (*opt != '/')
5239                         return -1; /* we expect -B80/99 or -B80 */
5240                 else {
5241                         opt++;
5242                         opt2 = parse_rename_score(&opt);
5243                 }
5244         }
5245         if (*opt != 0)
5246                 return -1;
5247         return opt1 | (opt2 << 16);
5248 }
5249
5250 struct diff_queue_struct diff_queued_diff;
5251
5252 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
5253 {
5254         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
5255         queue->queue[queue->nr++] = dp;
5256 }
5257
5258 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
5259                                  struct diff_filespec *one,
5260                                  struct diff_filespec *two)
5261 {
5262         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
5263         dp->one = one;
5264         dp->two = two;
5265         if (queue)
5266                 diff_q(queue, dp);
5267         return dp;
5268 }
5269
5270 void diff_free_filepair(struct diff_filepair *p)
5271 {
5272         free_filespec(p->one);
5273         free_filespec(p->two);
5274         free(p);
5275 }
5276
5277 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
5278 {
5279         int abblen;
5280         const char *abbrev;
5281
5282         /* Do we want all 40 hex characters? */
5283         if (len == the_hash_algo->hexsz)
5284                 return oid_to_hex(oid);
5285
5286         /* An abbreviated value is fine, possibly followed by an ellipsis. */
5287         abbrev = diff_abbrev_oid(oid, len);
5288
5289         if (!print_sha1_ellipsis())
5290                 return abbrev;
5291
5292         abblen = strlen(abbrev);
5293
5294         /*
5295          * In well-behaved cases, where the abbreviated result is the
5296          * same as the requested length, append three dots after the
5297          * abbreviation (hence the whole logic is limited to the case
5298          * where abblen < 37); when the actual abbreviated result is a
5299          * bit longer than the requested length, we reduce the number
5300          * of dots so that they match the well-behaved ones.  However,
5301          * if the actual abbreviation is longer than the requested
5302          * length by more than three, we give up on aligning, and add
5303          * three dots anyway, to indicate that the output is not the
5304          * full object name.  Yes, this may be suboptimal, but this
5305          * appears only in "diff --raw --abbrev" output and it is not
5306          * worth the effort to change it now.  Note that this would
5307          * likely to work fine when the automatic sizing of default
5308          * abbreviation length is used--we would be fed -1 in "len" in
5309          * that case, and will end up always appending three-dots, but
5310          * the automatic sizing is supposed to give abblen that ensures
5311          * uniqueness across all objects (statistically speaking).
5312          */
5313         if (abblen < the_hash_algo->hexsz - 3) {
5314                 static char hex[GIT_MAX_HEXSZ + 1];
5315                 if (len < abblen && abblen <= len + 2)
5316                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
5317                 else
5318                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
5319                 return hex;
5320         }
5321
5322         return oid_to_hex(oid);
5323 }
5324
5325 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5326 {
5327         int line_termination = opt->line_termination;
5328         int inter_name_termination = line_termination ? '\t' : '\0';
5329
5330         fprintf(opt->file, "%s", diff_line_prefix(opt));
5331         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5332                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5333                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5334                 fprintf(opt->file, "%s ",
5335                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5336         }
5337         if (p->score) {
5338                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5339                         inter_name_termination);
5340         } else {
5341                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5342         }
5343
5344         if (p->status == DIFF_STATUS_COPIED ||
5345             p->status == DIFF_STATUS_RENAMED) {
5346                 const char *name_a, *name_b;
5347                 name_a = p->one->path;
5348                 name_b = p->two->path;
5349                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5350                 write_name_quoted(name_a, opt->file, inter_name_termination);
5351                 write_name_quoted(name_b, opt->file, line_termination);
5352         } else {
5353                 const char *name_a, *name_b;
5354                 name_a = p->one->mode ? p->one->path : p->two->path;
5355                 name_b = NULL;
5356                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5357                 write_name_quoted(name_a, opt->file, line_termination);
5358         }
5359 }
5360
5361 int diff_unmodified_pair(struct diff_filepair *p)
5362 {
5363         /* This function is written stricter than necessary to support
5364          * the currently implemented transformers, but the idea is to
5365          * let transformers to produce diff_filepairs any way they want,
5366          * and filter and clean them up here before producing the output.
5367          */
5368         struct diff_filespec *one = p->one, *two = p->two;
5369
5370         if (DIFF_PAIR_UNMERGED(p))
5371                 return 0; /* unmerged is interesting */
5372
5373         /* deletion, addition, mode or type change
5374          * and rename are all interesting.
5375          */
5376         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5377             DIFF_PAIR_MODE_CHANGED(p) ||
5378             strcmp(one->path, two->path))
5379                 return 0;
5380
5381         /* both are valid and point at the same path.  that is, we are
5382          * dealing with a change.
5383          */
5384         if (one->oid_valid && two->oid_valid &&
5385             oideq(&one->oid, &two->oid) &&
5386             !one->dirty_submodule && !two->dirty_submodule)
5387                 return 1; /* no change */
5388         if (!one->oid_valid && !two->oid_valid)
5389                 return 1; /* both look at the same file on the filesystem. */
5390         return 0;
5391 }
5392
5393 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5394 {
5395         if (diff_unmodified_pair(p))
5396                 return;
5397
5398         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5399             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5400                 return; /* no tree diffs in patch format */
5401
5402         run_diff(p, o);
5403 }
5404
5405 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5406                             struct diffstat_t *diffstat)
5407 {
5408         if (diff_unmodified_pair(p))
5409                 return;
5410
5411         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5412             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5413                 return; /* no useful stat for tree diffs */
5414
5415         run_diffstat(p, o, diffstat);
5416 }
5417
5418 static void diff_flush_checkdiff(struct diff_filepair *p,
5419                 struct diff_options *o)
5420 {
5421         if (diff_unmodified_pair(p))
5422                 return;
5423
5424         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5425             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5426                 return; /* nothing to check in tree diffs */
5427
5428         run_checkdiff(p, o);
5429 }
5430
5431 int diff_queue_is_empty(void)
5432 {
5433         struct diff_queue_struct *q = &diff_queued_diff;
5434         int i;
5435         for (i = 0; i < q->nr; i++)
5436                 if (!diff_unmodified_pair(q->queue[i]))
5437                         return 0;
5438         return 1;
5439 }
5440
5441 #if DIFF_DEBUG
5442 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5443 {
5444         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5445                 x, one ? one : "",
5446                 s->path,
5447                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5448                 s->mode,
5449                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5450         fprintf(stderr, "queue[%d] %s size %lu\n",
5451                 x, one ? one : "",
5452                 s->size);
5453 }
5454
5455 void diff_debug_filepair(const struct diff_filepair *p, int i)
5456 {
5457         diff_debug_filespec(p->one, i, "one");
5458         diff_debug_filespec(p->two, i, "two");
5459         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5460                 p->score, p->status ? p->status : '?',
5461                 p->one->rename_used, p->broken_pair);
5462 }
5463
5464 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5465 {
5466         int i;
5467         if (msg)
5468                 fprintf(stderr, "%s\n", msg);
5469         fprintf(stderr, "q->nr = %d\n", q->nr);
5470         for (i = 0; i < q->nr; i++) {
5471                 struct diff_filepair *p = q->queue[i];
5472                 diff_debug_filepair(p, i);
5473         }
5474 }
5475 #endif
5476
5477 static void diff_resolve_rename_copy(void)
5478 {
5479         int i;
5480         struct diff_filepair *p;
5481         struct diff_queue_struct *q = &diff_queued_diff;
5482
5483         diff_debug_queue("resolve-rename-copy", q);
5484
5485         for (i = 0; i < q->nr; i++) {
5486                 p = q->queue[i];
5487                 p->status = 0; /* undecided */
5488                 if (DIFF_PAIR_UNMERGED(p))
5489                         p->status = DIFF_STATUS_UNMERGED;
5490                 else if (!DIFF_FILE_VALID(p->one))
5491                         p->status = DIFF_STATUS_ADDED;
5492                 else if (!DIFF_FILE_VALID(p->two))
5493                         p->status = DIFF_STATUS_DELETED;
5494                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5495                         p->status = DIFF_STATUS_TYPE_CHANGED;
5496
5497                 /* from this point on, we are dealing with a pair
5498                  * whose both sides are valid and of the same type, i.e.
5499                  * either in-place edit or rename/copy edit.
5500                  */
5501                 else if (DIFF_PAIR_RENAME(p)) {
5502                         /*
5503                          * A rename might have re-connected a broken
5504                          * pair up, causing the pathnames to be the
5505                          * same again. If so, that's not a rename at
5506                          * all, just a modification..
5507                          *
5508                          * Otherwise, see if this source was used for
5509                          * multiple renames, in which case we decrement
5510                          * the count, and call it a copy.
5511                          */
5512                         if (!strcmp(p->one->path, p->two->path))
5513                                 p->status = DIFF_STATUS_MODIFIED;
5514                         else if (--p->one->rename_used > 0)
5515                                 p->status = DIFF_STATUS_COPIED;
5516                         else
5517                                 p->status = DIFF_STATUS_RENAMED;
5518                 }
5519                 else if (!oideq(&p->one->oid, &p->two->oid) ||
5520                          p->one->mode != p->two->mode ||
5521                          p->one->dirty_submodule ||
5522                          p->two->dirty_submodule ||
5523                          is_null_oid(&p->one->oid))
5524                         p->status = DIFF_STATUS_MODIFIED;
5525                 else {
5526                         /* This is a "no-change" entry and should not
5527                          * happen anymore, but prepare for broken callers.
5528                          */
5529                         error("feeding unmodified %s to diffcore",
5530                               p->one->path);
5531                         p->status = DIFF_STATUS_UNKNOWN;
5532                 }
5533         }
5534         diff_debug_queue("resolve-rename-copy done", q);
5535 }
5536
5537 static int check_pair_status(struct diff_filepair *p)
5538 {
5539         switch (p->status) {
5540         case DIFF_STATUS_UNKNOWN:
5541                 return 0;
5542         case 0:
5543                 die("internal error in diff-resolve-rename-copy");
5544         default:
5545                 return 1;
5546         }
5547 }
5548
5549 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5550 {
5551         int fmt = opt->output_format;
5552
5553         if (fmt & DIFF_FORMAT_CHECKDIFF)
5554                 diff_flush_checkdiff(p, opt);
5555         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5556                 diff_flush_raw(p, opt);
5557         else if (fmt & DIFF_FORMAT_NAME) {
5558                 const char *name_a, *name_b;
5559                 name_a = p->two->path;
5560                 name_b = NULL;
5561                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5562                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5563                 write_name_quoted(name_a, opt->file, opt->line_termination);
5564         }
5565 }
5566
5567 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5568 {
5569         struct strbuf sb = STRBUF_INIT;
5570         if (fs->mode)
5571                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5572         else
5573                 strbuf_addf(&sb, " %s ", newdelete);
5574
5575         quote_c_style(fs->path, &sb, NULL, 0);
5576         strbuf_addch(&sb, '\n');
5577         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5578                          sb.buf, sb.len, 0);
5579         strbuf_release(&sb);
5580 }
5581
5582 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5583                 int show_name)
5584 {
5585         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5586                 struct strbuf sb = STRBUF_INIT;
5587                 strbuf_addf(&sb, " mode change %06o => %06o",
5588                             p->one->mode, p->two->mode);
5589                 if (show_name) {
5590                         strbuf_addch(&sb, ' ');
5591                         quote_c_style(p->two->path, &sb, NULL, 0);
5592                 }
5593                 strbuf_addch(&sb, '\n');
5594                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5595                                  sb.buf, sb.len, 0);
5596                 strbuf_release(&sb);
5597         }
5598 }
5599
5600 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5601                 struct diff_filepair *p)
5602 {
5603         struct strbuf sb = STRBUF_INIT;
5604         struct strbuf names = STRBUF_INIT;
5605
5606         pprint_rename(&names, p->one->path, p->two->path);
5607         strbuf_addf(&sb, " %s %s (%d%%)\n",
5608                     renamecopy, names.buf, similarity_index(p));
5609         strbuf_release(&names);
5610         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5611                                  sb.buf, sb.len, 0);
5612         show_mode_change(opt, p, 0);
5613         strbuf_release(&sb);
5614 }
5615
5616 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5617 {
5618         switch(p->status) {
5619         case DIFF_STATUS_DELETED:
5620                 show_file_mode_name(opt, "delete", p->one);
5621                 break;
5622         case DIFF_STATUS_ADDED:
5623                 show_file_mode_name(opt, "create", p->two);
5624                 break;
5625         case DIFF_STATUS_COPIED:
5626                 show_rename_copy(opt, "copy", p);
5627                 break;
5628         case DIFF_STATUS_RENAMED:
5629                 show_rename_copy(opt, "rename", p);
5630                 break;
5631         default:
5632                 if (p->score) {
5633                         struct strbuf sb = STRBUF_INIT;
5634                         strbuf_addstr(&sb, " rewrite ");
5635                         quote_c_style(p->two->path, &sb, NULL, 0);
5636                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5637                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5638                                          sb.buf, sb.len, 0);
5639                         strbuf_release(&sb);
5640                 }
5641                 show_mode_change(opt, p, !p->score);
5642                 break;
5643         }
5644 }
5645
5646 struct patch_id_t {
5647         git_SHA_CTX *ctx;
5648         int patchlen;
5649 };
5650
5651 static int remove_space(char *line, int len)
5652 {
5653         int i;
5654         char *dst = line;
5655         unsigned char c;
5656
5657         for (i = 0; i < len; i++)
5658                 if (!isspace((c = line[i])))
5659                         *dst++ = c;
5660
5661         return dst - line;
5662 }
5663
5664 static void patch_id_consume(void *priv, char *line, unsigned long len)
5665 {
5666         struct patch_id_t *data = priv;
5667         int new_len;
5668
5669         /* Ignore line numbers when computing the SHA1 of the patch */
5670         if (starts_with(line, "@@ -"))
5671                 return;
5672
5673         new_len = remove_space(line, len);
5674
5675         git_SHA1_Update(data->ctx, line, new_len);
5676         data->patchlen += new_len;
5677 }
5678
5679 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5680 {
5681         git_SHA1_Update(ctx, str, strlen(str));
5682 }
5683
5684 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5685 {
5686         /* large enough for 2^32 in octal */
5687         char buf[12];
5688         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5689         git_SHA1_Update(ctx, buf, len);
5690 }
5691
5692 /* returns 0 upon success, and writes result into sha1 */
5693 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5694 {
5695         struct diff_queue_struct *q = &diff_queued_diff;
5696         int i;
5697         git_SHA_CTX ctx;
5698         struct patch_id_t data;
5699
5700         git_SHA1_Init(&ctx);
5701         memset(&data, 0, sizeof(struct patch_id_t));
5702         data.ctx = &ctx;
5703
5704         for (i = 0; i < q->nr; i++) {
5705                 xpparam_t xpp;
5706                 xdemitconf_t xecfg;
5707                 mmfile_t mf1, mf2;
5708                 struct diff_filepair *p = q->queue[i];
5709                 int len1, len2;
5710
5711                 memset(&xpp, 0, sizeof(xpp));
5712                 memset(&xecfg, 0, sizeof(xecfg));
5713                 if (p->status == 0)
5714                         return error("internal diff status error");
5715                 if (p->status == DIFF_STATUS_UNKNOWN)
5716                         continue;
5717                 if (diff_unmodified_pair(p))
5718                         continue;
5719                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5720                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5721                         continue;
5722                 if (DIFF_PAIR_UNMERGED(p))
5723                         continue;
5724
5725                 diff_fill_oid_info(p->one, options->repo->index);
5726                 diff_fill_oid_info(p->two, options->repo->index);
5727
5728                 len1 = remove_space(p->one->path, strlen(p->one->path));
5729                 len2 = remove_space(p->two->path, strlen(p->two->path));
5730                 patch_id_add_string(&ctx, "diff--git");
5731                 patch_id_add_string(&ctx, "a/");
5732                 git_SHA1_Update(&ctx, p->one->path, len1);
5733                 patch_id_add_string(&ctx, "b/");
5734                 git_SHA1_Update(&ctx, p->two->path, len2);
5735
5736                 if (p->one->mode == 0) {
5737                         patch_id_add_string(&ctx, "newfilemode");
5738                         patch_id_add_mode(&ctx, p->two->mode);
5739                         patch_id_add_string(&ctx, "---/dev/null");
5740                         patch_id_add_string(&ctx, "+++b/");
5741                         git_SHA1_Update(&ctx, p->two->path, len2);
5742                 } else if (p->two->mode == 0) {
5743                         patch_id_add_string(&ctx, "deletedfilemode");
5744                         patch_id_add_mode(&ctx, p->one->mode);
5745                         patch_id_add_string(&ctx, "---a/");
5746                         git_SHA1_Update(&ctx, p->one->path, len1);
5747                         patch_id_add_string(&ctx, "+++/dev/null");
5748                 } else {
5749                         patch_id_add_string(&ctx, "---a/");
5750                         git_SHA1_Update(&ctx, p->one->path, len1);
5751                         patch_id_add_string(&ctx, "+++b/");
5752                         git_SHA1_Update(&ctx, p->two->path, len2);
5753                 }
5754
5755                 if (diff_header_only)
5756                         continue;
5757
5758                 if (fill_mmfile(options->repo, &mf1, p->one) < 0 ||
5759                     fill_mmfile(options->repo, &mf2, p->two) < 0)
5760                         return error("unable to read files to diff");
5761
5762                 if (diff_filespec_is_binary(options->repo, p->one) ||
5763                     diff_filespec_is_binary(options->repo, p->two)) {
5764                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5765                                         GIT_SHA1_HEXSZ);
5766                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5767                                         GIT_SHA1_HEXSZ);
5768                         continue;
5769                 }
5770
5771                 xpp.flags = 0;
5772                 xecfg.ctxlen = 3;
5773                 xecfg.flags = 0;
5774                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
5775                                   &xpp, &xecfg))
5776                         return error("unable to generate patch-id diff for %s",
5777                                      p->one->path);
5778         }
5779
5780         git_SHA1_Final(oid->hash, &ctx);
5781         return 0;
5782 }
5783
5784 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5785 {
5786         struct diff_queue_struct *q = &diff_queued_diff;
5787         int i;
5788         int result = diff_get_patch_id(options, oid, diff_header_only);
5789
5790         for (i = 0; i < q->nr; i++)
5791                 diff_free_filepair(q->queue[i]);
5792
5793         free(q->queue);
5794         DIFF_QUEUE_CLEAR(q);
5795
5796         return result;
5797 }
5798
5799 static int is_summary_empty(const struct diff_queue_struct *q)
5800 {
5801         int i;
5802
5803         for (i = 0; i < q->nr; i++) {
5804                 const struct diff_filepair *p = q->queue[i];
5805
5806                 switch (p->status) {
5807                 case DIFF_STATUS_DELETED:
5808                 case DIFF_STATUS_ADDED:
5809                 case DIFF_STATUS_COPIED:
5810                 case DIFF_STATUS_RENAMED:
5811                         return 0;
5812                 default:
5813                         if (p->score)
5814                                 return 0;
5815                         if (p->one->mode && p->two->mode &&
5816                             p->one->mode != p->two->mode)
5817                                 return 0;
5818                         break;
5819                 }
5820         }
5821         return 1;
5822 }
5823
5824 static const char rename_limit_warning[] =
5825 N_("inexact rename detection was skipped due to too many files.");
5826
5827 static const char degrade_cc_to_c_warning[] =
5828 N_("only found copies from modified paths due to too many files.");
5829
5830 static const char rename_limit_advice[] =
5831 N_("you may want to set your %s variable to at least "
5832    "%d and retry the command.");
5833
5834 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5835 {
5836         fflush(stdout);
5837         if (degraded_cc)
5838                 warning(_(degrade_cc_to_c_warning));
5839         else if (needed)
5840                 warning(_(rename_limit_warning));
5841         else
5842                 return;
5843         if (0 < needed)
5844                 warning(_(rename_limit_advice), varname, needed);
5845 }
5846
5847 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5848 {
5849         int i;
5850         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5851         struct diff_queue_struct *q = &diff_queued_diff;
5852
5853         if (WSEH_NEW & WS_RULE_MASK)
5854                 BUG("WS rules bit mask overlaps with diff symbol flags");
5855
5856         if (o->color_moved)
5857                 o->emitted_symbols = &esm;
5858
5859         for (i = 0; i < q->nr; i++) {
5860                 struct diff_filepair *p = q->queue[i];
5861                 if (check_pair_status(p))
5862                         diff_flush_patch(p, o);
5863         }
5864
5865         if (o->emitted_symbols) {
5866                 if (o->color_moved) {
5867                         struct hashmap add_lines, del_lines;
5868
5869                         if (o->color_moved_ws_handling &
5870                             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
5871                                 o->color_moved_ws_handling |= XDF_IGNORE_WHITESPACE;
5872
5873                         hashmap_init(&del_lines, moved_entry_cmp, o, 0);
5874                         hashmap_init(&add_lines, moved_entry_cmp, o, 0);
5875
5876                         add_lines_to_move_detection(o, &add_lines, &del_lines);
5877                         mark_color_as_moved(o, &add_lines, &del_lines);
5878                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5879                                 dim_moved_lines(o);
5880
5881                         hashmap_free(&add_lines, 1);
5882                         hashmap_free(&del_lines, 1);
5883                 }
5884
5885                 for (i = 0; i < esm.nr; i++)
5886                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
5887
5888                 for (i = 0; i < esm.nr; i++)
5889                         free((void *)esm.buf[i].line);
5890         }
5891         esm.nr = 0;
5892 }
5893
5894 void diff_flush(struct diff_options *options)
5895 {
5896         struct diff_queue_struct *q = &diff_queued_diff;
5897         int i, output_format = options->output_format;
5898         int separator = 0;
5899         int dirstat_by_line = 0;
5900
5901         /*
5902          * Order: raw, stat, summary, patch
5903          * or:    name/name-status/checkdiff (other bits clear)
5904          */
5905         if (!q->nr)
5906                 goto free_queue;
5907
5908         if (output_format & (DIFF_FORMAT_RAW |
5909                              DIFF_FORMAT_NAME |
5910                              DIFF_FORMAT_NAME_STATUS |
5911                              DIFF_FORMAT_CHECKDIFF)) {
5912                 for (i = 0; i < q->nr; i++) {
5913                         struct diff_filepair *p = q->queue[i];
5914                         if (check_pair_status(p))
5915                                 flush_one_pair(p, options);
5916                 }
5917                 separator++;
5918         }
5919
5920         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
5921                 dirstat_by_line = 1;
5922
5923         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5924             dirstat_by_line) {
5925                 struct diffstat_t diffstat;
5926
5927                 memset(&diffstat, 0, sizeof(struct diffstat_t));
5928                 for (i = 0; i < q->nr; i++) {
5929                         struct diff_filepair *p = q->queue[i];
5930                         if (check_pair_status(p))
5931                                 diff_flush_stat(p, options, &diffstat);
5932                 }
5933                 if (output_format & DIFF_FORMAT_NUMSTAT)
5934                         show_numstat(&diffstat, options);
5935                 if (output_format & DIFF_FORMAT_DIFFSTAT)
5936                         show_stats(&diffstat, options);
5937                 if (output_format & DIFF_FORMAT_SHORTSTAT)
5938                         show_shortstats(&diffstat, options);
5939                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5940                         show_dirstat_by_line(&diffstat, options);
5941                 free_diffstat_info(&diffstat);
5942                 separator++;
5943         }
5944         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5945                 show_dirstat(options);
5946
5947         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5948                 for (i = 0; i < q->nr; i++) {
5949                         diff_summary(options, q->queue[i]);
5950                 }
5951                 separator++;
5952         }
5953
5954         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5955             options->flags.exit_with_status &&
5956             options->flags.diff_from_contents) {
5957                 /*
5958                  * run diff_flush_patch for the exit status. setting
5959                  * options->file to /dev/null should be safe, because we
5960                  * aren't supposed to produce any output anyway.
5961                  */
5962                 if (options->close_file)
5963                         fclose(options->file);
5964                 options->file = xfopen("/dev/null", "w");
5965                 options->close_file = 1;
5966                 options->color_moved = 0;
5967                 for (i = 0; i < q->nr; i++) {
5968                         struct diff_filepair *p = q->queue[i];
5969                         if (check_pair_status(p))
5970                                 diff_flush_patch(p, options);
5971                         if (options->found_changes)
5972                                 break;
5973                 }
5974         }
5975
5976         if (output_format & DIFF_FORMAT_PATCH) {
5977                 if (separator) {
5978                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5979                         if (options->stat_sep)
5980                                 /* attach patch instead of inline */
5981                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5982                                                  NULL, 0, 0);
5983                 }
5984
5985                 diff_flush_patch_all_file_pairs(options);
5986         }
5987
5988         if (output_format & DIFF_FORMAT_CALLBACK)
5989                 options->format_callback(q, options, options->format_callback_data);
5990
5991         for (i = 0; i < q->nr; i++)
5992                 diff_free_filepair(q->queue[i]);
5993 free_queue:
5994         free(q->queue);
5995         DIFF_QUEUE_CLEAR(q);
5996         if (options->close_file)
5997                 fclose(options->file);
5998
5999         /*
6000          * Report the content-level differences with HAS_CHANGES;
6001          * diff_addremove/diff_change does not set the bit when
6002          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
6003          */
6004         if (options->flags.diff_from_contents) {
6005                 if (options->found_changes)
6006                         options->flags.has_changes = 1;
6007                 else
6008                         options->flags.has_changes = 0;
6009         }
6010 }
6011
6012 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
6013 {
6014         return (((p->status == DIFF_STATUS_MODIFIED) &&
6015                  ((p->score &&
6016                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
6017                   (!p->score &&
6018                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
6019                 ((p->status != DIFF_STATUS_MODIFIED) &&
6020                  filter_bit_tst(p->status, options)));
6021 }
6022
6023 static void diffcore_apply_filter(struct diff_options *options)
6024 {
6025         int i;
6026         struct diff_queue_struct *q = &diff_queued_diff;
6027         struct diff_queue_struct outq;
6028
6029         DIFF_QUEUE_CLEAR(&outq);
6030
6031         if (!options->filter)
6032                 return;
6033
6034         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
6035                 int found;
6036                 for (i = found = 0; !found && i < q->nr; i++) {
6037                         if (match_filter(options, q->queue[i]))
6038                                 found++;
6039                 }
6040                 if (found)
6041                         return;
6042
6043                 /* otherwise we will clear the whole queue
6044                  * by copying the empty outq at the end of this
6045                  * function, but first clear the current entries
6046                  * in the queue.
6047                  */
6048                 for (i = 0; i < q->nr; i++)
6049                         diff_free_filepair(q->queue[i]);
6050         }
6051         else {
6052                 /* Only the matching ones */
6053                 for (i = 0; i < q->nr; i++) {
6054                         struct diff_filepair *p = q->queue[i];
6055                         if (match_filter(options, p))
6056                                 diff_q(&outq, p);
6057                         else
6058                                 diff_free_filepair(p);
6059                 }
6060         }
6061         free(q->queue);
6062         *q = outq;
6063 }
6064
6065 /* Check whether two filespecs with the same mode and size are identical */
6066 static int diff_filespec_is_identical(struct repository *r,
6067                                       struct diff_filespec *one,
6068                                       struct diff_filespec *two)
6069 {
6070         if (S_ISGITLINK(one->mode))
6071                 return 0;
6072         if (diff_populate_filespec(r, one, 0))
6073                 return 0;
6074         if (diff_populate_filespec(r, two, 0))
6075                 return 0;
6076         return !memcmp(one->data, two->data, one->size);
6077 }
6078
6079 static int diff_filespec_check_stat_unmatch(struct repository *r,
6080                                             struct diff_filepair *p)
6081 {
6082         if (p->done_skip_stat_unmatch)
6083                 return p->skip_stat_unmatch_result;
6084
6085         p->done_skip_stat_unmatch = 1;
6086         p->skip_stat_unmatch_result = 0;
6087         /*
6088          * 1. Entries that come from stat info dirtiness
6089          *    always have both sides (iow, not create/delete),
6090          *    one side of the object name is unknown, with
6091          *    the same mode and size.  Keep the ones that
6092          *    do not match these criteria.  They have real
6093          *    differences.
6094          *
6095          * 2. At this point, the file is known to be modified,
6096          *    with the same mode and size, and the object
6097          *    name of one side is unknown.  Need to inspect
6098          *    the identical contents.
6099          */
6100         if (!DIFF_FILE_VALID(p->one) || /* (1) */
6101             !DIFF_FILE_VALID(p->two) ||
6102             (p->one->oid_valid && p->two->oid_valid) ||
6103             (p->one->mode != p->two->mode) ||
6104             diff_populate_filespec(r, p->one, CHECK_SIZE_ONLY) ||
6105             diff_populate_filespec(r, p->two, CHECK_SIZE_ONLY) ||
6106             (p->one->size != p->two->size) ||
6107             !diff_filespec_is_identical(r, p->one, p->two)) /* (2) */
6108                 p->skip_stat_unmatch_result = 1;
6109         return p->skip_stat_unmatch_result;
6110 }
6111
6112 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
6113 {
6114         int i;
6115         struct diff_queue_struct *q = &diff_queued_diff;
6116         struct diff_queue_struct outq;
6117         DIFF_QUEUE_CLEAR(&outq);
6118
6119         for (i = 0; i < q->nr; i++) {
6120                 struct diff_filepair *p = q->queue[i];
6121
6122                 if (diff_filespec_check_stat_unmatch(diffopt->repo, p))
6123                         diff_q(&outq, p);
6124                 else {
6125                         /*
6126                          * The caller can subtract 1 from skip_stat_unmatch
6127                          * to determine how many paths were dirty only
6128                          * due to stat info mismatch.
6129                          */
6130                         if (!diffopt->flags.no_index)
6131                                 diffopt->skip_stat_unmatch++;
6132                         diff_free_filepair(p);
6133                 }
6134         }
6135         free(q->queue);
6136         *q = outq;
6137 }
6138
6139 static int diffnamecmp(const void *a_, const void *b_)
6140 {
6141         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
6142         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
6143         const char *name_a, *name_b;
6144
6145         name_a = a->one ? a->one->path : a->two->path;
6146         name_b = b->one ? b->one->path : b->two->path;
6147         return strcmp(name_a, name_b);
6148 }
6149
6150 void diffcore_fix_diff_index(struct diff_options *options)
6151 {
6152         struct diff_queue_struct *q = &diff_queued_diff;
6153         QSORT(q->queue, q->nr, diffnamecmp);
6154 }
6155
6156 void diffcore_std(struct diff_options *options)
6157 {
6158         /* NOTE please keep the following in sync with diff_tree_combined() */
6159         if (options->skip_stat_unmatch)
6160                 diffcore_skip_stat_unmatch(options);
6161         if (!options->found_follow) {
6162                 /* See try_to_follow_renames() in tree-diff.c */
6163                 if (options->break_opt != -1)
6164                         diffcore_break(options->repo,
6165                                        options->break_opt);
6166                 if (options->detect_rename)
6167                         diffcore_rename(options);
6168                 if (options->break_opt != -1)
6169                         diffcore_merge_broken();
6170         }
6171         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
6172                 diffcore_pickaxe(options);
6173         if (options->orderfile)
6174                 diffcore_order(options->orderfile);
6175         if (!options->found_follow)
6176                 /* See try_to_follow_renames() in tree-diff.c */
6177                 diff_resolve_rename_copy();
6178         diffcore_apply_filter(options);
6179
6180         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
6181                 options->flags.has_changes = 1;
6182         else
6183                 options->flags.has_changes = 0;
6184
6185         options->found_follow = 0;
6186 }
6187
6188 int diff_result_code(struct diff_options *opt, int status)
6189 {
6190         int result = 0;
6191
6192         diff_warn_rename_limit("diff.renameLimit",
6193                                opt->needed_rename_limit,
6194                                opt->degraded_cc_to_c);
6195         if (!opt->flags.exit_with_status &&
6196             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
6197                 return status;
6198         if (opt->flags.exit_with_status &&
6199             opt->flags.has_changes)
6200                 result |= 01;
6201         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
6202             opt->flags.check_failed)
6203                 result |= 02;
6204         return result;
6205 }
6206
6207 int diff_can_quit_early(struct diff_options *opt)
6208 {
6209         return (opt->flags.quick &&
6210                 !opt->filter &&
6211                 opt->flags.has_changes);
6212 }
6213
6214 /*
6215  * Shall changes to this submodule be ignored?
6216  *
6217  * Submodule changes can be configured to be ignored separately for each path,
6218  * but that configuration can be overridden from the command line.
6219  */
6220 static int is_submodule_ignored(const char *path, struct diff_options *options)
6221 {
6222         int ignored = 0;
6223         struct diff_flags orig_flags = options->flags;
6224         if (!options->flags.override_submodule_config)
6225                 set_diffopt_flags_from_submodule_config(options, path);
6226         if (options->flags.ignore_submodules)
6227                 ignored = 1;
6228         options->flags = orig_flags;
6229         return ignored;
6230 }
6231
6232 void diff_addremove(struct diff_options *options,
6233                     int addremove, unsigned mode,
6234                     const struct object_id *oid,
6235                     int oid_valid,
6236                     const char *concatpath, unsigned dirty_submodule)
6237 {
6238         struct diff_filespec *one, *two;
6239
6240         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
6241                 return;
6242
6243         /* This may look odd, but it is a preparation for
6244          * feeding "there are unchanged files which should
6245          * not produce diffs, but when you are doing copy
6246          * detection you would need them, so here they are"
6247          * entries to the diff-core.  They will be prefixed
6248          * with something like '=' or '*' (I haven't decided
6249          * which but should not make any difference).
6250          * Feeding the same new and old to diff_change()
6251          * also has the same effect.
6252          * Before the final output happens, they are pruned after
6253          * merged into rename/copy pairs as appropriate.
6254          */
6255         if (options->flags.reverse_diff)
6256                 addremove = (addremove == '+' ? '-' :
6257                              addremove == '-' ? '+' : addremove);
6258
6259         if (options->prefix &&
6260             strncmp(concatpath, options->prefix, options->prefix_length))
6261                 return;
6262
6263         one = alloc_filespec(concatpath);
6264         two = alloc_filespec(concatpath);
6265
6266         if (addremove != '+')
6267                 fill_filespec(one, oid, oid_valid, mode);
6268         if (addremove != '-') {
6269                 fill_filespec(two, oid, oid_valid, mode);
6270                 two->dirty_submodule = dirty_submodule;
6271         }
6272
6273         diff_queue(&diff_queued_diff, one, two);
6274         if (!options->flags.diff_from_contents)
6275                 options->flags.has_changes = 1;
6276 }
6277
6278 void diff_change(struct diff_options *options,
6279                  unsigned old_mode, unsigned new_mode,
6280                  const struct object_id *old_oid,
6281                  const struct object_id *new_oid,
6282                  int old_oid_valid, int new_oid_valid,
6283                  const char *concatpath,
6284                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
6285 {
6286         struct diff_filespec *one, *two;
6287         struct diff_filepair *p;
6288
6289         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
6290             is_submodule_ignored(concatpath, options))
6291                 return;
6292
6293         if (options->flags.reverse_diff) {
6294                 SWAP(old_mode, new_mode);
6295                 SWAP(old_oid, new_oid);
6296                 SWAP(old_oid_valid, new_oid_valid);
6297                 SWAP(old_dirty_submodule, new_dirty_submodule);
6298         }
6299
6300         if (options->prefix &&
6301             strncmp(concatpath, options->prefix, options->prefix_length))
6302                 return;
6303
6304         one = alloc_filespec(concatpath);
6305         two = alloc_filespec(concatpath);
6306         fill_filespec(one, old_oid, old_oid_valid, old_mode);
6307         fill_filespec(two, new_oid, new_oid_valid, new_mode);
6308         one->dirty_submodule = old_dirty_submodule;
6309         two->dirty_submodule = new_dirty_submodule;
6310         p = diff_queue(&diff_queued_diff, one, two);
6311
6312         if (options->flags.diff_from_contents)
6313                 return;
6314
6315         if (options->flags.quick && options->skip_stat_unmatch &&
6316             !diff_filespec_check_stat_unmatch(options->repo, p))
6317                 return;
6318
6319         options->flags.has_changes = 1;
6320 }
6321
6322 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
6323 {
6324         struct diff_filepair *pair;
6325         struct diff_filespec *one, *two;
6326
6327         if (options->prefix &&
6328             strncmp(path, options->prefix, options->prefix_length))
6329                 return NULL;
6330
6331         one = alloc_filespec(path);
6332         two = alloc_filespec(path);
6333         pair = diff_queue(&diff_queued_diff, one, two);
6334         pair->is_unmerged = 1;
6335         return pair;
6336 }
6337
6338 static char *run_textconv(struct repository *r,
6339                           const char *pgm,
6340                           struct diff_filespec *spec,
6341                           size_t *outsize)
6342 {
6343         struct diff_tempfile *temp;
6344         const char *argv[3];
6345         const char **arg = argv;
6346         struct child_process child = CHILD_PROCESS_INIT;
6347         struct strbuf buf = STRBUF_INIT;
6348         int err = 0;
6349
6350         temp = prepare_temp_file(r, spec->path, spec);
6351         *arg++ = pgm;
6352         *arg++ = temp->name;
6353         *arg = NULL;
6354
6355         child.use_shell = 1;
6356         child.argv = argv;
6357         child.out = -1;
6358         if (start_command(&child)) {
6359                 remove_tempfile();
6360                 return NULL;
6361         }
6362
6363         if (strbuf_read(&buf, child.out, 0) < 0)
6364                 err = error("error reading from textconv command '%s'", pgm);
6365         close(child.out);
6366
6367         if (finish_command(&child) || err) {
6368                 strbuf_release(&buf);
6369                 remove_tempfile();
6370                 return NULL;
6371         }
6372         remove_tempfile();
6373
6374         return strbuf_detach(&buf, outsize);
6375 }
6376
6377 size_t fill_textconv(struct repository *r,
6378                      struct userdiff_driver *driver,
6379                      struct diff_filespec *df,
6380                      char **outbuf)
6381 {
6382         size_t size;
6383
6384         if (!driver) {
6385                 if (!DIFF_FILE_VALID(df)) {
6386                         *outbuf = "";
6387                         return 0;
6388                 }
6389                 if (diff_populate_filespec(r, df, 0))
6390                         die("unable to read files to diff");
6391                 *outbuf = df->data;
6392                 return df->size;
6393         }
6394
6395         if (!driver->textconv)
6396                 BUG("fill_textconv called with non-textconv driver");
6397
6398         if (driver->textconv_cache && df->oid_valid) {
6399                 *outbuf = notes_cache_get(driver->textconv_cache,
6400                                           &df->oid,
6401                                           &size);
6402                 if (*outbuf)
6403                         return size;
6404         }
6405
6406         *outbuf = run_textconv(r, driver->textconv, df, &size);
6407         if (!*outbuf)
6408                 die("unable to read files to diff");
6409
6410         if (driver->textconv_cache && df->oid_valid) {
6411                 /* ignore errors, as we might be in a readonly repository */
6412                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6413                                 size);
6414                 /*
6415                  * we could save up changes and flush them all at the end,
6416                  * but we would need an extra call after all diffing is done.
6417                  * Since generating a cache entry is the slow path anyway,
6418                  * this extra overhead probably isn't a big deal.
6419                  */
6420                 notes_cache_write(driver->textconv_cache);
6421         }
6422
6423         return size;
6424 }
6425
6426 int textconv_object(struct repository *r,
6427                     const char *path,
6428                     unsigned mode,
6429                     const struct object_id *oid,
6430                     int oid_valid,
6431                     char **buf,
6432                     unsigned long *buf_size)
6433 {
6434         struct diff_filespec *df;
6435         struct userdiff_driver *textconv;
6436
6437         df = alloc_filespec(path);
6438         fill_filespec(df, oid, oid_valid, mode);
6439         textconv = get_textconv(r->index, df);
6440         if (!textconv) {
6441                 free_filespec(df);
6442                 return 0;
6443         }
6444
6445         *buf_size = fill_textconv(r, textconv, df, buf);
6446         free_filespec(df);
6447         return 1;
6448 }
6449
6450 void setup_diff_pager(struct diff_options *opt)
6451 {
6452         /*
6453          * If the user asked for our exit code, then either they want --quiet
6454          * or --exit-code. We should definitely not bother with a pager in the
6455          * former case, as we will generate no output. Since we still properly
6456          * report our exit code even when a pager is run, we _could_ run a
6457          * pager with --exit-code. But since we have not done so historically,
6458          * and because it is easy to find people oneline advising "git diff
6459          * --exit-code" in hooks and other scripts, we do not do so.
6460          */
6461         if (!opt->flags.exit_with_status &&
6462             check_pager_config("diff") != 0)
6463                 setup_pager();
6464 }