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_context_default = 3;
  41 static int diff_interhunk_context_default;
  42 static const char *diff_word_regex_cfg;
  43 static const char *external_diff_cmd_cfg;
  44 static const char *diff_order_file_cfg;
  45 int diff_auto_refresh_index = 1;
  46 static int diff_mnemonic_prefix;
  47 static int diff_no_prefix;
  48 static int diff_stat_graph_width;
  49 static int diff_dirstat_permille_default = 30;
  50 static struct diff_options default_diff_options;
  51 static long diff_algorithm;
  52 static unsigned ws_error_highlight_default = WSEH_NEW;
  53
  54 static char diff_colors[][COLOR_MAXLEN] = {
  55         GIT_COLOR_RESET,
  56         GIT_COLOR_NORMAL,       /* CONTEXT */
  57         GIT_COLOR_BOLD,         /* METAINFO */
  58         GIT_COLOR_CYAN,         /* FRAGINFO */
  59         GIT_COLOR_RED,          /* OLD */
  60         GIT_COLOR_GREEN,        /* NEW */
  61         GIT_COLOR_YELLOW,       /* COMMIT */
  62         GIT_COLOR_BG_RED,       /* WHITESPACE */
  63         GIT_COLOR_NORMAL,       /* FUNCINFO */
  64         GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  65         GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  66         GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  67         GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  68         GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  69         GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  70         GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  71         GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  72 };
  73
  74 static const char *color_diff_slots[] = {
  75         [DIFF_CONTEXT]                = "context",
  76         [DIFF_METAINFO]               = "meta",
  77         [DIFF_FRAGINFO]               = "frag",
  78         [DIFF_FILE_OLD]               = "old",
  79         [DIFF_FILE_NEW]               = "new",
  80         [DIFF_COMMIT]                 = "commit",
  81         [DIFF_WHITESPACE]             = "whitespace",
  82         [DIFF_FUNCINFO]               = "func",
  83         [DIFF_FILE_OLD_MOVED]         = "oldMoved",
  84         [DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
  85         [DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
  86         [DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
  87         [DIFF_FILE_NEW_MOVED]         = "newMoved",
  88         [DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
  89         [DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
  90         [DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
  91 };
  92
  93 static NORETURN void die_want_option(const char *option_name)
  94 {
  95         die(_("option '%s' requires a value"), option_name);
  96 }
  97
  98 define_list_config_array_extra(color_diff_slots, {"plain"});
  99
 100 static int parse_diff_color_slot(const char *var)
 101 {
 102         if (!strcasecmp(var, "plain"))
 103                 return DIFF_CONTEXT;
 104         return LOOKUP_CONFIG(color_diff_slots, var);
 105 }
 106
 107 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 108                                 struct strbuf *errmsg)
 109 {
 110         char *params_copy = xstrdup(params_string);
 111         struct string_list params = STRING_LIST_INIT_NODUP;
 112         int ret = 0;
 113         int i;
 114
 115         if (*params_copy)
 116                 string_list_split_in_place(&params, params_copy, ',', -1);
 117         for (i = 0; i < params.nr; i++) {
 118                 const char *p = params.items[i].string;
 119                 if (!strcmp(p, "changes")) {
 120                         options->flags.dirstat_by_line = 0;
 121                         options->flags.dirstat_by_file = 0;
 122                 } else if (!strcmp(p, "lines")) {
 123                         options->flags.dirstat_by_line = 1;
 124                         options->flags.dirstat_by_file = 0;
 125                 } else if (!strcmp(p, "files")) {
 126                         options->flags.dirstat_by_line = 0;
 127                         options->flags.dirstat_by_file = 1;
 128                 } else if (!strcmp(p, "noncumulative")) {
 129                         options->flags.dirstat_cumulative = 0;
 130                 } else if (!strcmp(p, "cumulative")) {
 131                         options->flags.dirstat_cumulative = 1;
 132                 } else if (isdigit(*p)) {
 133                         char *end;
 134                         int permille = strtoul(p, &end, 10) * 10;
 135                         if (*end == '.' && isdigit(*++end)) {
 136                                 /* only use first digit */
 137                                 permille += *end - '0';
 138                                 /* .. and ignore any further digits */
 139                                 while (isdigit(*++end))
 140                                         ; /* nothing */
 141                         }
 142                         if (!*end)
 143                                 options->dirstat_permille = permille;
 144                         else {
 145                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 146                                             p);
 147                                 ret++;
 148                         }
 149                 } else {
 150                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 151                         ret++;
 152                 }
 153
 154         }
 155         string_list_clear(&params, 0);
 156         free(params_copy);
 157         return ret;
 158 }
 159
 160 static int parse_submodule_params(struct diff_options *options, const char *value)
 161 {
 162         if (!strcmp(value, "log"))
 163                 options->submodule_format = DIFF_SUBMODULE_LOG;
 164         else if (!strcmp(value, "short"))
 165                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 166         else if (!strcmp(value, "diff"))
 167                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 168         else
 169                 return -1;
 170         return 0;
 171 }
 172
 173 int git_config_rename(const char *var, const char *value)
 174 {
 175         if (!value)
 176                 return DIFF_DETECT_RENAME;
 177         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 178                 return  DIFF_DETECT_COPY;
 179         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 180 }
 181
 182 long parse_algorithm_value(const char *value)
 183 {
 184         if (!value)
 185                 return -1;
 186         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 187                 return 0;
 188         else if (!strcasecmp(value, "minimal"))
 189                 return XDF_NEED_MINIMAL;
 190         else if (!strcasecmp(value, "patience"))
 191                 return XDF_PATIENCE_DIFF;
 192         else if (!strcasecmp(value, "histogram"))
 193                 return XDF_HISTOGRAM_DIFF;
 194         return -1;
 195 }
 196
 197 static int parse_one_token(const char **arg, const char *token)
 198 {
 199         const char *rest;
 200         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 201                 *arg = rest;
 202                 return 1;
 203         }
 204         return 0;
 205 }
 206
 207 static int parse_ws_error_highlight(const char *arg)
 208 {
 209         const char *orig_arg = arg;
 210         unsigned val = 0;
 211
 212         while (*arg) {
 213                 if (parse_one_token(&arg, "none"))
 214                         val = 0;
 215                 else if (parse_one_token(&arg, "default"))
 216                         val = WSEH_NEW;
 217                 else if (parse_one_token(&arg, "all"))
 218                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 219                 else if (parse_one_token(&arg, "new"))
 220                         val |= WSEH_NEW;
 221                 else if (parse_one_token(&arg, "old"))
 222                         val |= WSEH_OLD;
 223                 else if (parse_one_token(&arg, "context"))
 224                         val |= WSEH_CONTEXT;
 225                 else {
 226                         return -1 - (int)(arg - orig_arg);
 227                 }
 228                 if (*arg)
 229                         arg++;
 230         }
 231         return val;
 232 }
 233
 234 /*
 235  * These are to give UI layer defaults.
 236  * The core-level commands such as git-diff-files should
 237  * never be affected by the setting of diff.renames
 238  * the user happens to have in the configuration file.
 239  */
 240 void init_diff_ui_defaults(void)
 241 {
 242         diff_detect_rename_default = DIFF_DETECT_RENAME;
 243 }
 244
 245 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 246 {
 247         if (!strcmp(var, "diff.indentheuristic"))
 248                 diff_indent_heuristic = git_config_bool(var, value);
 249         return 0;
 250 }
 251
 252 static int parse_color_moved(const char *arg)
 253 {
 254         switch (git_parse_maybe_bool(arg)) {
 255         case 0:
 256                 return COLOR_MOVED_NO;
 257         case 1:
 258                 return COLOR_MOVED_DEFAULT;
 259         default:
 260                 break;
 261         }
 262
 263         if (!strcmp(arg, "no"))
 264                 return COLOR_MOVED_NO;
 265         else if (!strcmp(arg, "plain"))
 266                 return COLOR_MOVED_PLAIN;
 267         else if (!strcmp(arg, "zebra"))
 268                 return COLOR_MOVED_ZEBRA;
 269         else if (!strcmp(arg, "default"))
 270                 return COLOR_MOVED_DEFAULT;
 271         else if (!strcmp(arg, "dimmed_zebra"))
 272                 return COLOR_MOVED_ZEBRA_DIM;
 273         else
 274                 return error(_("color moved setting must be one of 'no', 'default', 'zebra', 'dimmed_zebra', 'plain'"));
 275 }
 276
 277 int git_diff_ui_config(const char *var, const char *value, void *cb)
 278 {
 279         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 280                 diff_use_color_default = git_config_colorbool(var, value);
 281                 return 0;
 282         }
 283         if (!strcmp(var, "diff.colormoved")) {
 284                 int cm = parse_color_moved(value);
 285                 if (cm < 0)
 286                         return -1;
 287                 diff_color_moved_default = cm;
 288                 return 0;
 289         }
 290         if (!strcmp(var, "diff.context")) {
 291                 diff_context_default = git_config_int(var, value);
 292                 if (diff_context_default < 0)
 293                         return -1;
 294                 return 0;
 295         }
 296         if (!strcmp(var, "diff.interhunkcontext")) {
 297                 diff_interhunk_context_default = git_config_int(var, value);
 298                 if (diff_interhunk_context_default < 0)
 299                         return -1;
 300                 return 0;
 301         }
 302         if (!strcmp(var, "diff.renames")) {
 303                 diff_detect_rename_default = git_config_rename(var, value);
 304                 return 0;
 305         }
 306         if (!strcmp(var, "diff.autorefreshindex")) {
 307                 diff_auto_refresh_index = git_config_bool(var, value);
 308                 return 0;
 309         }
 310         if (!strcmp(var, "diff.mnemonicprefix")) {
 311                 diff_mnemonic_prefix = git_config_bool(var, value);
 312                 return 0;
 313         }
 314         if (!strcmp(var, "diff.noprefix")) {
 315                 diff_no_prefix = git_config_bool(var, value);
 316                 return 0;
 317         }
 318         if (!strcmp(var, "diff.statgraphwidth")) {
 319                 diff_stat_graph_width = git_config_int(var, value);
 320                 return 0;
 321         }
 322         if (!strcmp(var, "diff.external"))
 323                 return git_config_string(&external_diff_cmd_cfg, var, value);
 324         if (!strcmp(var, "diff.wordregex"))
 325                 return git_config_string(&diff_word_regex_cfg, var, value);
 326         if (!strcmp(var, "diff.orderfile"))
 327                 return git_config_pathname(&diff_order_file_cfg, var, value);
 328
 329         if (!strcmp(var, "diff.ignoresubmodules"))
 330                 handle_ignore_submodules_arg(&default_diff_options, value);
 331
 332         if (!strcmp(var, "diff.submodule")) {
 333                 if (parse_submodule_params(&default_diff_options, value))
 334                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 335                                 value);
 336                 return 0;
 337         }
 338
 339         if (!strcmp(var, "diff.algorithm")) {
 340                 diff_algorithm = parse_algorithm_value(value);
 341                 if (diff_algorithm < 0)
 342                         return -1;
 343                 return 0;
 344         }
 345
 346         if (!strcmp(var, "diff.wserrorhighlight")) {
 347                 int val = parse_ws_error_highlight(value);
 348                 if (val < 0)
 349                         return -1;
 350                 ws_error_highlight_default = val;
 351                 return 0;
 352         }
 353
 354         if (git_color_config(var, value, cb) < 0)
 355                 return -1;
 356
 357         return git_diff_basic_config(var, value, cb);
 358 }
 359
 360 int git_diff_basic_config(const char *var, const char *value, void *cb)
 361 {
 362         const char *name;
 363
 364         if (!strcmp(var, "diff.renamelimit")) {
 365                 diff_rename_limit_default = git_config_int(var, value);
 366                 return 0;
 367         }
 368
 369         if (userdiff_config(var, value) < 0)
 370                 return -1;
 371
 372         if (skip_prefix(var, "diff.color.", &name) ||
 373             skip_prefix(var, "color.diff.", &name)) {
 374                 int slot = parse_diff_color_slot(name);
 375                 if (slot < 0)
 376                         return 0;
 377                 if (!value)
 378                         return config_error_nonbool(var);
 379                 return color_parse(value, diff_colors[slot]);
 380         }
 381
 382         /* like GNU diff's --suppress-blank-empty option  */
 383         if (!strcmp(var, "diff.suppressblankempty") ||
 384                         /* for backwards compatibility */
 385                         !strcmp(var, "diff.suppress-blank-empty")) {
 386                 diff_suppress_blank_empty = git_config_bool(var, value);
 387                 return 0;
 388         }
 389
 390         if (!strcmp(var, "diff.dirstat")) {
 391                 struct strbuf errmsg = STRBUF_INIT;
 392                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 393                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 394                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 395                                 errmsg.buf);
 396                 strbuf_release(&errmsg);
 397                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 398                 return 0;
 399         }
 400
 401         if (git_diff_heuristic_config(var, value, cb) < 0)
 402                 return -1;
 403
 404         return git_default_config(var, value, cb);
 405 }
 406
 407 static char *quote_two(const char *one, const char *two)
 408 {
 409         int need_one = quote_c_style(one, NULL, NULL, 1);
 410         int need_two = quote_c_style(two, NULL, NULL, 1);
 411         struct strbuf res = STRBUF_INIT;
 412
 413         if (need_one + need_two) {
 414                 strbuf_addch(&res, '"');
 415                 quote_c_style(one, &res, NULL, 1);
 416                 quote_c_style(two, &res, NULL, 1);
 417                 strbuf_addch(&res, '"');
 418         } else {
 419                 strbuf_addstr(&res, one);
 420                 strbuf_addstr(&res, two);
 421         }
 422         return strbuf_detach(&res, NULL);
 423 }
 424
 425 static const char *external_diff(void)
 426 {
 427         static const char *external_diff_cmd = NULL;
 428         static int done_preparing = 0;
 429
 430         if (done_preparing)
 431                 return external_diff_cmd;
 432         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 433         if (!external_diff_cmd)
 434                 external_diff_cmd = external_diff_cmd_cfg;
 435         done_preparing = 1;
 436         return external_diff_cmd;
 437 }
 438
 439 /*
 440  * Keep track of files used for diffing. Sometimes such an entry
 441  * refers to a temporary file, sometimes to an existing file, and
 442  * sometimes to "/dev/null".
 443  */
 444 static struct diff_tempfile {
 445         /*
 446          * filename external diff should read from, or NULL if this
 447          * entry is currently not in use:
 448          */
 449         const char *name;
 450
 451         char hex[GIT_MAX_HEXSZ + 1];
 452         char mode[10];
 453
 454         /*
 455          * If this diff_tempfile instance refers to a temporary file,
 456          * this tempfile object is used to manage its lifetime.
 457          */
 458         struct tempfile *tempfile;
 459 } diff_temp[2];
 460
 461 struct emit_callback {
 462         int color_diff;
 463         unsigned ws_rule;
 464         int blank_at_eof_in_preimage;
 465         int blank_at_eof_in_postimage;
 466         int lno_in_preimage;
 467         int lno_in_postimage;
 468         const char **label_path;
 469         struct diff_words_data *diff_words;
 470         struct diff_options *opt;
 471         struct strbuf *header;
 472 };
 473
 474 static int count_lines(const char *data, int size)
 475 {
 476         int count, ch, completely_empty = 1, nl_just_seen = 0;
 477         count = 0;
 478         while (0 < size--) {
 479                 ch = *data++;
 480                 if (ch == '\n') {
 481                         count++;
 482                         nl_just_seen = 1;
 483                         completely_empty = 0;
 484                 }
 485                 else {
 486                         nl_just_seen = 0;
 487                         completely_empty = 0;
 488                 }
 489         }
 490         if (completely_empty)
 491                 return 0;
 492         if (!nl_just_seen)
 493                 count++; /* no trailing newline */
 494         return count;
 495 }
 496
 497 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 498 {
 499         if (!DIFF_FILE_VALID(one)) {
 500                 mf->ptr = (char *)""; /* does not matter */
 501                 mf->size = 0;
 502                 return 0;
 503         }
 504         else if (diff_populate_filespec(one, 0))
 505                 return -1;
 506
 507         mf->ptr = one->data;
 508         mf->size = one->size;
 509         return 0;
 510 }
 511
 512 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 513 static unsigned long diff_filespec_size(struct diff_filespec *one)
 514 {
 515         if (!DIFF_FILE_VALID(one))
 516                 return 0;
 517         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 518         return one->size;
 519 }
 520
 521 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 522 {
 523         char *ptr = mf->ptr;
 524         long size = mf->size;
 525         int cnt = 0;
 526
 527         if (!size)
 528                 return cnt;
 529         ptr += size - 1; /* pointing at the very end */
 530         if (*ptr != '\n')
 531                 ; /* incomplete line */
 532         else
 533                 ptr--; /* skip the last LF */
 534         while (mf->ptr < ptr) {
 535                 char *prev_eol;
 536                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 537                         if (*prev_eol == '\n')
 538                                 break;
 539                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 540                         break;
 541                 cnt++;
 542                 ptr = prev_eol - 1;
 543         }
 544         return cnt;
 545 }
 546
 547 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 548                                struct emit_callback *ecbdata)
 549 {
 550         int l1, l2, at;
 551         unsigned ws_rule = ecbdata->ws_rule;
 552         l1 = count_trailing_blank(mf1, ws_rule);
 553         l2 = count_trailing_blank(mf2, ws_rule);
 554         if (l2 <= l1) {
 555                 ecbdata->blank_at_eof_in_preimage = 0;
 556                 ecbdata->blank_at_eof_in_postimage = 0;
 557                 return;
 558         }
 559         at = count_lines(mf1->ptr, mf1->size);
 560         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 561
 562         at = count_lines(mf2->ptr, mf2->size);
 563         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 564 }
 565
 566 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 567                         int first, const char *line, int len)
 568 {
 569         int has_trailing_newline, has_trailing_carriage_return;
 570         int nofirst;
 571         FILE *file = o->file;
 572
 573         fputs(diff_line_prefix(o), file);
 574
 575         if (len == 0) {
 576                 has_trailing_newline = (first == '\n');
 577                 has_trailing_carriage_return = (!has_trailing_newline &&
 578                                                 (first == '\r'));
 579                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 580         } else {
 581                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 582                 if (has_trailing_newline)
 583                         len--;
 584                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 585                 if (has_trailing_carriage_return)
 586                         len--;
 587                 nofirst = 0;
 588         }
 589
 590         if (len || !nofirst) {
 591                 fputs(set, file);
 592                 if (!nofirst)
 593                         fputc(first, file);
 594                 fwrite(line, len, 1, file);
 595                 fputs(reset, file);
 596         }
 597         if (has_trailing_carriage_return)
 598                 fputc('\r', file);
 599         if (has_trailing_newline)
 600                 fputc('\n', file);
 601 }
 602
 603 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 604                       const char *line, int len)
 605 {
 606         emit_line_0(o, set, reset, line[0], line+1, len-1);
 607 }
 608
 609 enum diff_symbol {
 610         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 611         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 612         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 613         DIFF_SYMBOL_BINARY_DIFF_BODY,
 614         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 615         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 616         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 617         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 618         DIFF_SYMBOL_STATS_LINE,
 619         DIFF_SYMBOL_WORD_DIFF,
 620         DIFF_SYMBOL_STAT_SEP,
 621         DIFF_SYMBOL_SUMMARY,
 622         DIFF_SYMBOL_SUBMODULE_ADD,
 623         DIFF_SYMBOL_SUBMODULE_DEL,
 624         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 625         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 626         DIFF_SYMBOL_SUBMODULE_HEADER,
 627         DIFF_SYMBOL_SUBMODULE_ERROR,
 628         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 629         DIFF_SYMBOL_REWRITE_DIFF,
 630         DIFF_SYMBOL_BINARY_FILES,
 631         DIFF_SYMBOL_HEADER,
 632         DIFF_SYMBOL_FILEPAIR_PLUS,
 633         DIFF_SYMBOL_FILEPAIR_MINUS,
 634         DIFF_SYMBOL_WORDS_PORCELAIN,
 635         DIFF_SYMBOL_WORDS,
 636         DIFF_SYMBOL_CONTEXT,
 637         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 638         DIFF_SYMBOL_PLUS,
 639         DIFF_SYMBOL_MINUS,
 640         DIFF_SYMBOL_NO_LF_EOF,
 641         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 642         DIFF_SYMBOL_CONTEXT_MARKER,
 643         DIFF_SYMBOL_SEPARATOR
 644 };
 645 /*
 646  * Flags for content lines:
 647  * 0..12 are whitespace rules
 648  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 649  * 16 is marking if the line is blank at EOF
 650  */
 651 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 652 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 653 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 654 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 655 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 656
 657 /*
 658  * This struct is used when we need to buffer the output of the diff output.
 659  *
 660  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 661  * into the pre/post image file. This pointer could be a union with the
 662  * line pointer. By storing an offset into the file instead of the literal line,
 663  * we can decrease the memory footprint for the buffered output. At first we
 664  * may want to only have indirection for the content lines, but we could also
 665  * enhance the state for emitting prefabricated lines, e.g. the similarity
 666  * score line or hunk/file headers would only need to store a number or path
 667  * and then the output can be constructed later on depending on state.
 668  */
 669 struct emitted_diff_symbol {
 670         const char *line;
 671         int len;
 672         int flags;
 673         enum diff_symbol s;
 674 };
 675 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 676
 677 struct emitted_diff_symbols {
 678         struct emitted_diff_symbol *buf;
 679         int nr, alloc;
 680 };
 681 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 682
 683 static void append_emitted_diff_symbol(struct diff_options *o,
 684                                        struct emitted_diff_symbol *e)
 685 {
 686         struct emitted_diff_symbol *f;
 687
 688         ALLOC_GROW(o->emitted_symbols->buf,
 689                    o->emitted_symbols->nr + 1,
 690                    o->emitted_symbols->alloc);
 691         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 692
 693         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 694         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 695 }
 696
 697 struct moved_entry {
 698         struct hashmap_entry ent;
 699         const struct emitted_diff_symbol *es;
 700         struct moved_entry *next_line;
 701 };
 702
 703 static int moved_entry_cmp(const struct diff_options *diffopt,
 704                            const struct moved_entry *a,
 705                            const struct moved_entry *b,
 706                            const void *keydata)
 707 {
 708         return !xdiff_compare_lines(a->es->line, a->es->len,
 709                                     b->es->line, b->es->len,
 710                                     diffopt->xdl_opts);
 711 }
 712
 713 static struct moved_entry *prepare_entry(struct diff_options *o,
 714                                          int line_no)
 715 {
 716         struct moved_entry *ret = xmalloc(sizeof(*ret));
 717         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 718
 719         ret->ent.hash = xdiff_hash_string(l->line, l->len, o->xdl_opts);
 720         ret->es = l;
 721         ret->next_line = NULL;
 722
 723         return ret;
 724 }
 725
 726 static void add_lines_to_move_detection(struct diff_options *o,
 727                                         struct hashmap *add_lines,
 728                                         struct hashmap *del_lines)
 729 {
 730         struct moved_entry *prev_line = NULL;
 731
 732         int n;
 733         for (n = 0; n < o->emitted_symbols->nr; n++) {
 734                 struct hashmap *hm;
 735                 struct moved_entry *key;
 736
 737                 switch (o->emitted_symbols->buf[n].s) {
 738                 case DIFF_SYMBOL_PLUS:
 739                         hm = add_lines;
 740                         break;
 741                 case DIFF_SYMBOL_MINUS:
 742                         hm = del_lines;
 743                         break;
 744                 default:
 745                         prev_line = NULL;
 746                         continue;
 747                 }
 748
 749                 key = prepare_entry(o, n);
 750                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 751                         prev_line->next_line = key;
 752
 753                 hashmap_add(hm, key);
 754                 prev_line = key;
 755         }
 756 }
 757
 758 static int shrink_potential_moved_blocks(struct moved_entry **pmb,
 759                                          int pmb_nr)
 760 {
 761         int lp, rp;
 762
 763         /* Shrink the set of potential block to the remaining running */
 764         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
 765                 while (lp < pmb_nr && pmb[lp])
 766                         lp++;
 767                 /* lp points at the first NULL now */
 768
 769                 while (rp > -1 && !pmb[rp])
 770                         rp--;
 771                 /* rp points at the last non-NULL */
 772
 773                 if (lp < pmb_nr && rp > -1 && lp < rp) {
 774                         pmb[lp] = pmb[rp];
 775                         pmb[rp] = NULL;
 776                         rp--;
 777                         lp++;
 778                 }
 779         }
 780
 781         /* Remember the number of running sets */
 782         return rp + 1;
 783 }
 784
 785 /*
 786  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
 787  *
 788  * Otherwise, if the last block has fewer alphanumeric characters than
 789  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
 790  * that block.
 791  *
 792  * The last block consists of the (n - block_length)'th line up to but not
 793  * including the nth line.
 794  *
 795  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
 796  * Think of a way to unify them.
 797  */
 798 static void adjust_last_block(struct diff_options *o, int n, int block_length)
 799 {
 800         int i, alnum_count = 0;
 801         if (o->color_moved == COLOR_MOVED_PLAIN)
 802                 return;
 803         for (i = 1; i < block_length + 1; i++) {
 804                 const char *c = o->emitted_symbols->buf[n - i].line;
 805                 for (; *c; c++) {
 806                         if (!isalnum(*c))
 807                                 continue;
 808                         alnum_count++;
 809                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
 810                                 return;
 811                 }
 812         }
 813         for (i = 1; i < block_length + 1; i++)
 814                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
 815 }
 816
 817 /* Find blocks of moved code, delegate actual coloring decision to helper */
 818 static void mark_color_as_moved(struct diff_options *o,
 819                                 struct hashmap *add_lines,
 820                                 struct hashmap *del_lines)
 821 {
 822         struct moved_entry **pmb = NULL; /* potentially moved blocks */
 823         int pmb_nr = 0, pmb_alloc = 0;
 824         int n, flipped_block = 1, block_length = 0;
 825
 826
 827         for (n = 0; n < o->emitted_symbols->nr; n++) {
 828                 struct hashmap *hm = NULL;
 829                 struct moved_entry *key;
 830                 struct moved_entry *match = NULL;
 831                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 832                 int i;
 833
 834                 switch (l->s) {
 835                 case DIFF_SYMBOL_PLUS:
 836                         hm = del_lines;
 837                         key = prepare_entry(o, n);
 838                         match = hashmap_get(hm, key, o);
 839                         free(key);
 840                         break;
 841                 case DIFF_SYMBOL_MINUS:
 842                         hm = add_lines;
 843                         key = prepare_entry(o, n);
 844                         match = hashmap_get(hm, key, o);
 845                         free(key);
 846                         break;
 847                 default:
 848                         flipped_block = 1;
 849                 }
 850
 851                 if (!match) {
 852                         adjust_last_block(o, n, block_length);
 853                         pmb_nr = 0;
 854                         block_length = 0;
 855                         continue;
 856                 }
 857
 858                 l->flags |= DIFF_SYMBOL_MOVED_LINE;
 859
 860                 if (o->color_moved == COLOR_MOVED_PLAIN)
 861                         continue;
 862
 863                 /* Check any potential block runs, advance each or nullify */
 864                 for (i = 0; i < pmb_nr; i++) {
 865                         struct moved_entry *p = pmb[i];
 866                         struct moved_entry *pnext = (p && p->next_line) ?
 867                                         p->next_line : NULL;
 868                         if (pnext && !hm->cmpfn(o, pnext, match, NULL)) {
 869                                 pmb[i] = p->next_line;
 870                         } else {
 871                                 pmb[i] = NULL;
 872                         }
 873                 }
 874
 875                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
 876
 877                 if (pmb_nr == 0) {
 878                         /*
 879                          * The current line is the start of a new block.
 880                          * Setup the set of potential blocks.
 881                          */
 882                         for (; match; match = hashmap_get_next(hm, match)) {
 883                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
 884                                 pmb[pmb_nr++] = match;
 885                         }
 886
 887                         flipped_block = (flipped_block + 1) % 2;
 888
 889                         adjust_last_block(o, n, block_length);
 890                         block_length = 0;
 891                 }
 892
 893                 block_length++;
 894
 895                 if (flipped_block)
 896                         l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
 897         }
 898         adjust_last_block(o, n, block_length);
 899
 900         free(pmb);
 901 }
 902
 903 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
 904   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
 905 static void dim_moved_lines(struct diff_options *o)
 906 {
 907         int n;
 908         for (n = 0; n < o->emitted_symbols->nr; n++) {
 909                 struct emitted_diff_symbol *prev = (n != 0) ?
 910                                 &o->emitted_symbols->buf[n - 1] : NULL;
 911                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 912                 struct emitted_diff_symbol *next =
 913                                 (n < o->emitted_symbols->nr - 1) ?
 914                                 &o->emitted_symbols->buf[n + 1] : NULL;
 915
 916                 /* Not a plus or minus line? */
 917                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
 918                         continue;
 919
 920                 /* Not a moved line? */
 921                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
 922                         continue;
 923
 924                 /*
 925                  * If prev or next are not a plus or minus line,
 926                  * pretend they don't exist
 927                  */
 928                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
 929                             prev->s != DIFF_SYMBOL_MINUS)
 930                         prev = NULL;
 931                 if (next && next->s != DIFF_SYMBOL_PLUS &&
 932                             next->s != DIFF_SYMBOL_MINUS)
 933                         next = NULL;
 934
 935                 /* Inside a block? */
 936                 if ((prev &&
 937                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
 938                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
 939                     (next &&
 940                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
 941                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
 942                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
 943                         continue;
 944                 }
 945
 946                 /* Check if we are at an interesting bound: */
 947                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
 948                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
 949                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
 950                         continue;
 951                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
 952                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
 953                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
 954                         continue;
 955
 956                 /*
 957                  * The boundary to prev and next are not interesting,
 958                  * so this line is not interesting as a whole
 959                  */
 960                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
 961         }
 962 }
 963
 964 static void emit_line_ws_markup(struct diff_options *o,
 965                                 const char *set, const char *reset,
 966                                 const char *line, int len, char sign,
 967                                 unsigned ws_rule, int blank_at_eof)
 968 {
 969         const char *ws = NULL;
 970
 971         if (o->ws_error_highlight & ws_rule) {
 972                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
 973                 if (!*ws)
 974                         ws = NULL;
 975         }
 976
 977         if (!ws)
 978                 emit_line_0(o, set, reset, sign, line, len);
 979         else if (blank_at_eof)
 980                 /* Blank line at EOF - paint '+' as well */
 981                 emit_line_0(o, ws, reset, sign, line, len);
 982         else {
 983                 /* Emit just the prefix, then the rest. */
 984                 emit_line_0(o, set, reset, sign, "", 0);
 985                 ws_check_emit(line, len, ws_rule,
 986                               o->file, set, reset, ws);
 987         }
 988 }
 989
 990 static void emit_diff_symbol_from_struct(struct diff_options *o,
 991                                          struct emitted_diff_symbol *eds)
 992 {
 993         static const char *nneof = " No newline at end of file\n";
 994         const char *context, *reset, *set, *meta, *fraginfo;
 995         struct strbuf sb = STRBUF_INIT;
 996
 997         enum diff_symbol s = eds->s;
 998         const char *line = eds->line;
 999         int len = eds->len;
1000         unsigned flags = eds->flags;
1001
1002         switch (s) {
1003         case DIFF_SYMBOL_NO_LF_EOF:
1004                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1005                 reset = diff_get_color_opt(o, DIFF_RESET);
1006                 putc('\n', o->file);
1007                 emit_line_0(o, context, reset, '\\',
1008                             nneof, strlen(nneof));
1009                 break;
1010         case DIFF_SYMBOL_SUBMODULE_HEADER:
1011         case DIFF_SYMBOL_SUBMODULE_ERROR:
1012         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1013         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1014         case DIFF_SYMBOL_SUMMARY:
1015         case DIFF_SYMBOL_STATS_LINE:
1016         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1017         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1018                 emit_line(o, "", "", line, len);
1019                 break;
1020         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1021         case DIFF_SYMBOL_CONTEXT_MARKER:
1022                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1023                 reset = diff_get_color_opt(o, DIFF_RESET);
1024                 emit_line(o, context, reset, line, len);
1025                 break;
1026         case DIFF_SYMBOL_SEPARATOR:
1027                 fprintf(o->file, "%s%c",
1028                         diff_line_prefix(o),
1029                         o->line_termination);
1030                 break;
1031         case DIFF_SYMBOL_CONTEXT:
1032                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1033                 reset = diff_get_color_opt(o, DIFF_RESET);
1034                 emit_line_ws_markup(o, set, reset, line, len, ' ',
1035                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1036                 break;
1037         case DIFF_SYMBOL_PLUS:
1038                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1039                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1040                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1041                 case DIFF_SYMBOL_MOVED_LINE |
1042                      DIFF_SYMBOL_MOVED_LINE_ALT |
1043                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1044                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1045                         break;
1046                 case DIFF_SYMBOL_MOVED_LINE |
1047                      DIFF_SYMBOL_MOVED_LINE_ALT:
1048                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1049                         break;
1050                 case DIFF_SYMBOL_MOVED_LINE |
1051                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1052                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1053                         break;
1054                 case DIFF_SYMBOL_MOVED_LINE:
1055                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1056                         break;
1057                 default:
1058                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1059                 }
1060                 reset = diff_get_color_opt(o, DIFF_RESET);
1061                 emit_line_ws_markup(o, set, reset, line, len, '+',
1062                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1063                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1064                 break;
1065         case DIFF_SYMBOL_MINUS:
1066                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1067                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1068                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1069                 case DIFF_SYMBOL_MOVED_LINE |
1070                      DIFF_SYMBOL_MOVED_LINE_ALT |
1071                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1072                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1073                         break;
1074                 case DIFF_SYMBOL_MOVED_LINE |
1075                      DIFF_SYMBOL_MOVED_LINE_ALT:
1076                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1077                         break;
1078                 case DIFF_SYMBOL_MOVED_LINE |
1079                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1080                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1081                         break;
1082                 case DIFF_SYMBOL_MOVED_LINE:
1083                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1084                         break;
1085                 default:
1086                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1087                 }
1088                 reset = diff_get_color_opt(o, DIFF_RESET);
1089                 emit_line_ws_markup(o, set, reset, line, len, '-',
1090                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1091                 break;
1092         case DIFF_SYMBOL_WORDS_PORCELAIN:
1093                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1094                 reset = diff_get_color_opt(o, DIFF_RESET);
1095                 emit_line(o, context, reset, line, len);
1096                 fputs("~\n", o->file);
1097                 break;
1098         case DIFF_SYMBOL_WORDS:
1099                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1100                 reset = diff_get_color_opt(o, DIFF_RESET);
1101                 /*
1102                  * Skip the prefix character, if any.  With
1103                  * diff_suppress_blank_empty, there may be
1104                  * none.
1105                  */
1106                 if (line[0] != '\n') {
1107                         line++;
1108                         len--;
1109                 }
1110                 emit_line(o, context, reset, line, len);
1111                 break;
1112         case DIFF_SYMBOL_FILEPAIR_PLUS:
1113                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1114                 reset = diff_get_color_opt(o, DIFF_RESET);
1115                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1116                         line, reset,
1117                         strchr(line, ' ') ? "\t" : "");
1118                 break;
1119         case DIFF_SYMBOL_FILEPAIR_MINUS:
1120                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1121                 reset = diff_get_color_opt(o, DIFF_RESET);
1122                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1123                         line, reset,
1124                         strchr(line, ' ') ? "\t" : "");
1125                 break;
1126         case DIFF_SYMBOL_BINARY_FILES:
1127         case DIFF_SYMBOL_HEADER:
1128                 fprintf(o->file, "%s", line);
1129                 break;
1130         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1131                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1132                 break;
1133         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1134                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1135                 break;
1136         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1137                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1138                 break;
1139         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1140                 fputs(diff_line_prefix(o), o->file);
1141                 fputc('\n', o->file);
1142                 break;
1143         case DIFF_SYMBOL_REWRITE_DIFF:
1144                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1145                 reset = diff_get_color_opt(o, DIFF_RESET);
1146                 emit_line(o, fraginfo, reset, line, len);
1147                 break;
1148         case DIFF_SYMBOL_SUBMODULE_ADD:
1149                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1150                 reset = diff_get_color_opt(o, DIFF_RESET);
1151                 emit_line(o, set, reset, line, len);
1152                 break;
1153         case DIFF_SYMBOL_SUBMODULE_DEL:
1154                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1155                 reset = diff_get_color_opt(o, DIFF_RESET);
1156                 emit_line(o, set, reset, line, len);
1157                 break;
1158         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1159                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1160                         diff_line_prefix(o), line);
1161                 break;
1162         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1163                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1164                         diff_line_prefix(o), line);
1165                 break;
1166         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1167                 emit_line(o, "", "", " 0 files changed\n",
1168                           strlen(" 0 files changed\n"));
1169                 break;
1170         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1171                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1172                 break;
1173         case DIFF_SYMBOL_WORD_DIFF:
1174                 fprintf(o->file, "%.*s", len, line);
1175                 break;
1176         case DIFF_SYMBOL_STAT_SEP:
1177                 fputs(o->stat_sep, o->file);
1178                 break;
1179         default:
1180                 BUG("unknown diff symbol");
1181         }
1182         strbuf_release(&sb);
1183 }
1184
1185 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1186                              const char *line, int len, unsigned flags)
1187 {
1188         struct emitted_diff_symbol e = {line, len, flags, s};
1189
1190         if (o->emitted_symbols)
1191                 append_emitted_diff_symbol(o, &e);
1192         else
1193                 emit_diff_symbol_from_struct(o, &e);
1194 }
1195
1196 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1197 {
1198         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1199 }
1200
1201 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1202 {
1203         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1204 }
1205
1206 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1207 {
1208         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1209                          path, strlen(path), 0);
1210 }
1211
1212 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1213 {
1214         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1215                          path, strlen(path), 0);
1216 }
1217
1218 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1219 {
1220         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1221                          header, strlen(header), 0);
1222 }
1223
1224 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1225 {
1226         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1227 }
1228
1229 void diff_emit_submodule_pipethrough(struct diff_options *o,
1230                                      const char *line, int len)
1231 {
1232         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1233 }
1234
1235 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1236 {
1237         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1238               ecbdata->blank_at_eof_in_preimage &&
1239               ecbdata->blank_at_eof_in_postimage &&
1240               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1241               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1242                 return 0;
1243         return ws_blank_line(line, len, ecbdata->ws_rule);
1244 }
1245
1246 static void emit_add_line(const char *reset,
1247                           struct emit_callback *ecbdata,
1248                           const char *line, int len)
1249 {
1250         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1251         if (new_blank_line_at_eof(ecbdata, line, len))
1252                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1253
1254         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1255 }
1256
1257 static void emit_del_line(const char *reset,
1258                           struct emit_callback *ecbdata,
1259                           const char *line, int len)
1260 {
1261         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1262         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1263 }
1264
1265 static void emit_context_line(const char *reset,
1266                               struct emit_callback *ecbdata,
1267                               const char *line, int len)
1268 {
1269         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1270         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1271 }
1272
1273 static void emit_hunk_header(struct emit_callback *ecbdata,
1274                              const char *line, int len)
1275 {
1276         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1277         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1278         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1279         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1280         static const char atat[2] = { '@', '@' };
1281         const char *cp, *ep;
1282         struct strbuf msgbuf = STRBUF_INIT;
1283         int org_len = len;
1284         int i = 1;
1285
1286         /*
1287          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1288          * it always is at least 10 bytes long.
1289          */
1290         if (len < 10 ||
1291             memcmp(line, atat, 2) ||
1292             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1293                 emit_diff_symbol(ecbdata->opt,
1294                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1295                 return;
1296         }
1297         ep += 2; /* skip over @@ */
1298
1299         /* The hunk header in fraginfo color */
1300         strbuf_addstr(&msgbuf, frag);
1301         strbuf_add(&msgbuf, line, ep - line);
1302         strbuf_addstr(&msgbuf, reset);
1303
1304         /*
1305          * trailing "\r\n"
1306          */
1307         for ( ; i < 3; i++)
1308                 if (line[len - i] == '\r' || line[len - i] == '\n')
1309                         len--;
1310
1311         /* blank before the func header */
1312         for (cp = ep; ep - line < len; ep++)
1313                 if (*ep != ' ' && *ep != '\t')
1314                         break;
1315         if (ep != cp) {
1316                 strbuf_addstr(&msgbuf, context);
1317                 strbuf_add(&msgbuf, cp, ep - cp);
1318                 strbuf_addstr(&msgbuf, reset);
1319         }
1320
1321         if (ep < line + len) {
1322                 strbuf_addstr(&msgbuf, func);
1323                 strbuf_add(&msgbuf, ep, line + len - ep);
1324                 strbuf_addstr(&msgbuf, reset);
1325         }
1326
1327         strbuf_add(&msgbuf, line + len, org_len - len);
1328         strbuf_complete_line(&msgbuf);
1329         emit_diff_symbol(ecbdata->opt,
1330                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1331         strbuf_release(&msgbuf);
1332 }
1333
1334 static struct diff_tempfile *claim_diff_tempfile(void) {
1335         int i;
1336         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1337                 if (!diff_temp[i].name)
1338                         return diff_temp + i;
1339         BUG("diff is failing to clean up its tempfiles");
1340 }
1341
1342 static void remove_tempfile(void)
1343 {
1344         int i;
1345         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1346                 if (is_tempfile_active(diff_temp[i].tempfile))
1347                         delete_tempfile(&diff_temp[i].tempfile);
1348                 diff_temp[i].name = NULL;
1349         }
1350 }
1351
1352 static void add_line_count(struct strbuf *out, int count)
1353 {
1354         switch (count) {
1355         case 0:
1356                 strbuf_addstr(out, "0,0");
1357                 break;
1358         case 1:
1359                 strbuf_addstr(out, "1");
1360                 break;
1361         default:
1362                 strbuf_addf(out, "1,%d", count);
1363                 break;
1364         }
1365 }
1366
1367 static void emit_rewrite_lines(struct emit_callback *ecb,
1368                                int prefix, const char *data, int size)
1369 {
1370         const char *endp = NULL;
1371         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1372
1373         while (0 < size) {
1374                 int len;
1375
1376                 endp = memchr(data, '\n', size);
1377                 len = endp ? (endp - data + 1) : size;
1378                 if (prefix != '+') {
1379                         ecb->lno_in_preimage++;
1380                         emit_del_line(reset, ecb, data, len);
1381                 } else {
1382                         ecb->lno_in_postimage++;
1383                         emit_add_line(reset, ecb, data, len);
1384                 }
1385                 size -= len;
1386                 data += len;
1387         }
1388         if (!endp)
1389                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1390 }
1391
1392 static void emit_rewrite_diff(const char *name_a,
1393                               const char *name_b,
1394                               struct diff_filespec *one,
1395                               struct diff_filespec *two,
1396                               struct userdiff_driver *textconv_one,
1397                               struct userdiff_driver *textconv_two,
1398                               struct diff_options *o)
1399 {
1400         int lc_a, lc_b;
1401         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1402         const char *a_prefix, *b_prefix;
1403         char *data_one, *data_two;
1404         size_t size_one, size_two;
1405         struct emit_callback ecbdata;
1406         struct strbuf out = STRBUF_INIT;
1407
1408         if (diff_mnemonic_prefix && o->flags.reverse_diff) {
1409                 a_prefix = o->b_prefix;
1410                 b_prefix = o->a_prefix;
1411         } else {
1412                 a_prefix = o->a_prefix;
1413                 b_prefix = o->b_prefix;
1414         }
1415
1416         name_a += (*name_a == '/');
1417         name_b += (*name_b == '/');
1418
1419         strbuf_reset(&a_name);
1420         strbuf_reset(&b_name);
1421         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1422         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1423
1424         size_one = fill_textconv(textconv_one, one, &data_one);
1425         size_two = fill_textconv(textconv_two, two, &data_two);
1426
1427         memset(&ecbdata, 0, sizeof(ecbdata));
1428         ecbdata.color_diff = want_color(o->use_color);
1429         ecbdata.ws_rule = whitespace_rule(name_b);
1430         ecbdata.opt = o;
1431         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1432                 mmfile_t mf1, mf2;
1433                 mf1.ptr = (char *)data_one;
1434                 mf2.ptr = (char *)data_two;
1435                 mf1.size = size_one;
1436                 mf2.size = size_two;
1437                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1438         }
1439         ecbdata.lno_in_preimage = 1;
1440         ecbdata.lno_in_postimage = 1;
1441
1442         lc_a = count_lines(data_one, size_one);
1443         lc_b = count_lines(data_two, size_two);
1444
1445         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1446                          a_name.buf, a_name.len, 0);
1447         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1448                          b_name.buf, b_name.len, 0);
1449
1450         strbuf_addstr(&out, "@@ -");
1451         if (!o->irreversible_delete)
1452                 add_line_count(&out, lc_a);
1453         else
1454                 strbuf_addstr(&out, "?,?");
1455         strbuf_addstr(&out, " +");
1456         add_line_count(&out, lc_b);
1457         strbuf_addstr(&out, " @@\n");
1458         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1459         strbuf_release(&out);
1460
1461         if (lc_a && !o->irreversible_delete)
1462                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1463         if (lc_b)
1464                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1465         if (textconv_one)
1466                 free((char *)data_one);
1467         if (textconv_two)
1468                 free((char *)data_two);
1469 }
1470
1471 struct diff_words_buffer {
1472         mmfile_t text;
1473         unsigned long alloc;
1474         struct diff_words_orig {
1475                 const char *begin, *end;
1476         } *orig;
1477         int orig_nr, orig_alloc;
1478 };
1479
1480 static void diff_words_append(char *line, unsigned long len,
1481                 struct diff_words_buffer *buffer)
1482 {
1483         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1484         line++;
1485         len--;
1486         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1487         buffer->text.size += len;
1488         buffer->text.ptr[buffer->text.size] = '\0';
1489 }
1490
1491 struct diff_words_style_elem {
1492         const char *prefix;
1493         const char *suffix;
1494         const char *color; /* NULL; filled in by the setup code if
1495                             * color is enabled */
1496 };
1497
1498 struct diff_words_style {
1499         enum diff_words_type type;
1500         struct diff_words_style_elem new_word, old_word, ctx;
1501         const char *newline;
1502 };
1503
1504 static struct diff_words_style diff_words_styles[] = {
1505         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1506         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1507         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1508 };
1509
1510 struct diff_words_data {
1511         struct diff_words_buffer minus, plus;
1512         const char *current_plus;
1513         int last_minus;
1514         struct diff_options *opt;
1515         regex_t *word_regex;
1516         enum diff_words_type type;
1517         struct diff_words_style *style;
1518 };
1519
1520 static int fn_out_diff_words_write_helper(struct diff_options *o,
1521                                           struct diff_words_style_elem *st_el,
1522                                           const char *newline,
1523                                           size_t count, const char *buf)
1524 {
1525         int print = 0;
1526         struct strbuf sb = STRBUF_INIT;
1527
1528         while (count) {
1529                 char *p = memchr(buf, '\n', count);
1530                 if (print)
1531                         strbuf_addstr(&sb, diff_line_prefix(o));
1532
1533                 if (p != buf) {
1534                         const char *reset = st_el->color && *st_el->color ?
1535                                             GIT_COLOR_RESET : NULL;
1536                         if (st_el->color && *st_el->color)
1537                                 strbuf_addstr(&sb, st_el->color);
1538                         strbuf_addstr(&sb, st_el->prefix);
1539                         strbuf_add(&sb, buf, p ? p - buf : count);
1540                         strbuf_addstr(&sb, st_el->suffix);
1541                         if (reset)
1542                                 strbuf_addstr(&sb, reset);
1543                 }
1544                 if (!p)
1545                         goto out;
1546
1547                 strbuf_addstr(&sb, newline);
1548                 count -= p + 1 - buf;
1549                 buf = p + 1;
1550                 print = 1;
1551                 if (count) {
1552                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1553                                          sb.buf, sb.len, 0);
1554                         strbuf_reset(&sb);
1555                 }
1556         }
1557
1558 out:
1559         if (sb.len)
1560                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1561                                  sb.buf, sb.len, 0);
1562         strbuf_release(&sb);
1563         return 0;
1564 }
1565
1566 /*
1567  * '--color-words' algorithm can be described as:
1568  *
1569  *   1. collect the minus/plus lines of a diff hunk, divided into
1570  *      minus-lines and plus-lines;
1571  *
1572  *   2. break both minus-lines and plus-lines into words and
1573  *      place them into two mmfile_t with one word for each line;
1574  *
1575  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1576  *
1577  * And for the common parts of the both file, we output the plus side text.
1578  * diff_words->current_plus is used to trace the current position of the plus file
1579  * which printed. diff_words->last_minus is used to trace the last minus word
1580  * printed.
1581  *
1582  * For '--graph' to work with '--color-words', we need to output the graph prefix
1583  * on each line of color words output. Generally, there are two conditions on
1584  * which we should output the prefix.
1585  *
1586  *   1. diff_words->last_minus == 0 &&
1587  *      diff_words->current_plus == diff_words->plus.text.ptr
1588  *
1589  *      that is: the plus text must start as a new line, and if there is no minus
1590  *      word printed, a graph prefix must be printed.
1591  *
1592  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1593  *      *(diff_words->current_plus - 1) == '\n'
1594  *
1595  *      that is: a graph prefix must be printed following a '\n'
1596  */
1597 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1598 {
1599         if ((diff_words->last_minus == 0 &&
1600                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1601                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1602                 *(diff_words->current_plus - 1) == '\n')) {
1603                 return 1;
1604         } else {
1605                 return 0;
1606         }
1607 }
1608
1609 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1610 {
1611         struct diff_words_data *diff_words = priv;
1612         struct diff_words_style *style = diff_words->style;
1613         int minus_first, minus_len, plus_first, plus_len;
1614         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1615         struct diff_options *opt = diff_words->opt;
1616         const char *line_prefix;
1617
1618         if (line[0] != '@' || parse_hunk_header(line, len,
1619                         &minus_first, &minus_len, &plus_first, &plus_len))
1620                 return;
1621
1622         assert(opt);
1623         line_prefix = diff_line_prefix(opt);
1624
1625         /* POSIX requires that first be decremented by one if len == 0... */
1626         if (minus_len) {
1627                 minus_begin = diff_words->minus.orig[minus_first].begin;
1628                 minus_end =
1629                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1630         } else
1631                 minus_begin = minus_end =
1632                         diff_words->minus.orig[minus_first].end;
1633
1634         if (plus_len) {
1635                 plus_begin = diff_words->plus.orig[plus_first].begin;
1636                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1637         } else
1638                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1639
1640         if (color_words_output_graph_prefix(diff_words)) {
1641                 fputs(line_prefix, diff_words->opt->file);
1642         }
1643         if (diff_words->current_plus != plus_begin) {
1644                 fn_out_diff_words_write_helper(diff_words->opt,
1645                                 &style->ctx, style->newline,
1646                                 plus_begin - diff_words->current_plus,
1647                                 diff_words->current_plus);
1648         }
1649         if (minus_begin != minus_end) {
1650                 fn_out_diff_words_write_helper(diff_words->opt,
1651                                 &style->old_word, style->newline,
1652                                 minus_end - minus_begin, minus_begin);
1653         }
1654         if (plus_begin != plus_end) {
1655                 fn_out_diff_words_write_helper(diff_words->opt,
1656                                 &style->new_word, style->newline,
1657                                 plus_end - plus_begin, plus_begin);
1658         }
1659
1660         diff_words->current_plus = plus_end;
1661         diff_words->last_minus = minus_first;
1662 }
1663
1664 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1665 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1666                 int *begin, int *end)
1667 {
1668         if (word_regex && *begin < buffer->size) {
1669                 regmatch_t match[1];
1670                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1671                                  buffer->size - *begin, 1, match, 0)) {
1672                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1673                                         '\n', match[0].rm_eo - match[0].rm_so);
1674                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1675                         *begin += match[0].rm_so;
1676                         return *begin >= *end;
1677                 }
1678                 return -1;
1679         }
1680
1681         /* find the next word */
1682         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1683                 (*begin)++;
1684         if (*begin >= buffer->size)
1685                 return -1;
1686
1687         /* find the end of the word */
1688         *end = *begin + 1;
1689         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1690                 (*end)++;
1691
1692         return 0;
1693 }
1694
1695 /*
1696  * This function splits the words in buffer->text, stores the list with
1697  * newline separator into out, and saves the offsets of the original words
1698  * in buffer->orig.
1699  */
1700 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1701                 regex_t *word_regex)
1702 {
1703         int i, j;
1704         long alloc = 0;
1705
1706         out->size = 0;
1707         out->ptr = NULL;
1708
1709         /* fake an empty "0th" word */
1710         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1711         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1712         buffer->orig_nr = 1;
1713
1714         for (i = 0; i < buffer->text.size; i++) {
1715                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1716                         return;
1717
1718                 /* store original boundaries */
1719                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1720                                 buffer->orig_alloc);
1721                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1722                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1723                 buffer->orig_nr++;
1724
1725                 /* store one word */
1726                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1727                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1728                 out->ptr[out->size + j - i] = '\n';
1729                 out->size += j - i + 1;
1730
1731                 i = j - 1;
1732         }
1733 }
1734
1735 /* this executes the word diff on the accumulated buffers */
1736 static void diff_words_show(struct diff_words_data *diff_words)
1737 {
1738         xpparam_t xpp;
1739         xdemitconf_t xecfg;
1740         mmfile_t minus, plus;
1741         struct diff_words_style *style = diff_words->style;
1742
1743         struct diff_options *opt = diff_words->opt;
1744         const char *line_prefix;
1745
1746         assert(opt);
1747         line_prefix = diff_line_prefix(opt);
1748
1749         /* special case: only removal */
1750         if (!diff_words->plus.text.size) {
1751                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1752                                  line_prefix, strlen(line_prefix), 0);
1753                 fn_out_diff_words_write_helper(diff_words->opt,
1754                         &style->old_word, style->newline,
1755                         diff_words->minus.text.size,
1756                         diff_words->minus.text.ptr);
1757                 diff_words->minus.text.size = 0;
1758                 return;
1759         }
1760
1761         diff_words->current_plus = diff_words->plus.text.ptr;
1762         diff_words->last_minus = 0;
1763
1764         memset(&xpp, 0, sizeof(xpp));
1765         memset(&xecfg, 0, sizeof(xecfg));
1766         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1767         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1768         xpp.flags = 0;
1769         /* as only the hunk header will be parsed, we need a 0-context */
1770         xecfg.ctxlen = 0;
1771         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1772                           &xpp, &xecfg))
1773                 die("unable to generate word diff");
1774         free(minus.ptr);
1775         free(plus.ptr);
1776         if (diff_words->current_plus != diff_words->plus.text.ptr +
1777                         diff_words->plus.text.size) {
1778                 if (color_words_output_graph_prefix(diff_words))
1779                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1780                                          line_prefix, strlen(line_prefix), 0);
1781                 fn_out_diff_words_write_helper(diff_words->opt,
1782                         &style->ctx, style->newline,
1783                         diff_words->plus.text.ptr + diff_words->plus.text.size
1784                         - diff_words->current_plus, diff_words->current_plus);
1785         }
1786         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1787 }
1788
1789 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1790 static void diff_words_flush(struct emit_callback *ecbdata)
1791 {
1792         struct diff_options *wo = ecbdata->diff_words->opt;
1793
1794         if (ecbdata->diff_words->minus.text.size ||
1795             ecbdata->diff_words->plus.text.size)
1796                 diff_words_show(ecbdata->diff_words);
1797
1798         if (wo->emitted_symbols) {
1799                 struct diff_options *o = ecbdata->opt;
1800                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
1801                 int i;
1802
1803                 /*
1804                  * NEEDSWORK:
1805                  * Instead of appending each, concat all words to a line?
1806                  */
1807                 for (i = 0; i < wol->nr; i++)
1808                         append_emitted_diff_symbol(o, &wol->buf[i]);
1809
1810                 for (i = 0; i < wol->nr; i++)
1811                         free((void *)wol->buf[i].line);
1812
1813                 wol->nr = 0;
1814         }
1815 }
1816
1817 static void diff_filespec_load_driver(struct diff_filespec *one)
1818 {
1819         /* Use already-loaded driver */
1820         if (one->driver)
1821                 return;
1822
1823         if (S_ISREG(one->mode))
1824                 one->driver = userdiff_find_by_path(one->path);
1825
1826         /* Fallback to default settings */
1827         if (!one->driver)
1828                 one->driver = userdiff_find_by_name("default");
1829 }
1830
1831 static const char *userdiff_word_regex(struct diff_filespec *one)
1832 {
1833         diff_filespec_load_driver(one);
1834         return one->driver->word_regex;
1835 }
1836
1837 static void init_diff_words_data(struct emit_callback *ecbdata,
1838                                  struct diff_options *orig_opts,
1839                                  struct diff_filespec *one,
1840                                  struct diff_filespec *two)
1841 {
1842         int i;
1843         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1844         memcpy(o, orig_opts, sizeof(struct diff_options));
1845
1846         ecbdata->diff_words =
1847                 xcalloc(1, sizeof(struct diff_words_data));
1848         ecbdata->diff_words->type = o->word_diff;
1849         ecbdata->diff_words->opt = o;
1850
1851         if (orig_opts->emitted_symbols)
1852                 o->emitted_symbols =
1853                         xcalloc(1, sizeof(struct emitted_diff_symbols));
1854
1855         if (!o->word_regex)
1856                 o->word_regex = userdiff_word_regex(one);
1857         if (!o->word_regex)
1858                 o->word_regex = userdiff_word_regex(two);
1859         if (!o->word_regex)
1860                 o->word_regex = diff_word_regex_cfg;
1861         if (o->word_regex) {
1862                 ecbdata->diff_words->word_regex = (regex_t *)
1863                         xmalloc(sizeof(regex_t));
1864                 if (regcomp(ecbdata->diff_words->word_regex,
1865                             o->word_regex,
1866                             REG_EXTENDED | REG_NEWLINE))
1867                         die ("Invalid regular expression: %s",
1868                              o->word_regex);
1869         }
1870         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1871                 if (o->word_diff == diff_words_styles[i].type) {
1872                         ecbdata->diff_words->style =
1873                                 &diff_words_styles[i];
1874                         break;
1875                 }
1876         }
1877         if (want_color(o->use_color)) {
1878                 struct diff_words_style *st = ecbdata->diff_words->style;
1879                 st->old_word.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1880                 st->new_word.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1881                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1882         }
1883 }
1884
1885 static void free_diff_words_data(struct emit_callback *ecbdata)
1886 {
1887         if (ecbdata->diff_words) {
1888                 diff_words_flush(ecbdata);
1889                 free (ecbdata->diff_words->opt->emitted_symbols);
1890                 free (ecbdata->diff_words->opt);
1891                 free (ecbdata->diff_words->minus.text.ptr);
1892                 free (ecbdata->diff_words->minus.orig);
1893                 free (ecbdata->diff_words->plus.text.ptr);
1894                 free (ecbdata->diff_words->plus.orig);
1895                 if (ecbdata->diff_words->word_regex) {
1896                         regfree(ecbdata->diff_words->word_regex);
1897                         free(ecbdata->diff_words->word_regex);
1898                 }
1899                 FREE_AND_NULL(ecbdata->diff_words);
1900         }
1901 }
1902
1903 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1904 {
1905         if (want_color(diff_use_color))
1906                 return diff_colors[ix];
1907         return "";
1908 }
1909
1910 const char *diff_line_prefix(struct diff_options *opt)
1911 {
1912         struct strbuf *msgbuf;
1913         if (!opt->output_prefix)
1914                 return "";
1915
1916         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1917         return msgbuf->buf;
1918 }
1919
1920 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1921 {
1922         const char *cp;
1923         unsigned long allot;
1924         size_t l = len;
1925
1926         cp = line;
1927         allot = l;
1928         while (0 < l) {
1929                 (void) utf8_width(&cp, &l);
1930                 if (!cp)
1931                         break; /* truncated in the middle? */
1932         }
1933         return allot - l;
1934 }
1935
1936 static void find_lno(const char *line, struct emit_callback *ecbdata)
1937 {
1938         const char *p;
1939         ecbdata->lno_in_preimage = 0;
1940         ecbdata->lno_in_postimage = 0;
1941         p = strchr(line, '-');
1942         if (!p)
1943                 return; /* cannot happen */
1944         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1945         p = strchr(p, '+');
1946         if (!p)
1947                 return; /* cannot happen */
1948         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1949 }
1950
1951 static void fn_out_consume(void *priv, char *line, unsigned long len)
1952 {
1953         struct emit_callback *ecbdata = priv;
1954         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1955         struct diff_options *o = ecbdata->opt;
1956
1957         o->found_changes = 1;
1958
1959         if (ecbdata->header) {
1960                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
1961                                  ecbdata->header->buf, ecbdata->header->len, 0);
1962                 strbuf_reset(ecbdata->header);
1963                 ecbdata->header = NULL;
1964         }
1965
1966         if (ecbdata->label_path[0]) {
1967                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1968                                  ecbdata->label_path[0],
1969                                  strlen(ecbdata->label_path[0]), 0);
1970                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1971                                  ecbdata->label_path[1],
1972                                  strlen(ecbdata->label_path[1]), 0);
1973                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1974         }
1975
1976         if (diff_suppress_blank_empty
1977             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1978                 line[0] = '\n';
1979                 len = 1;
1980         }
1981
1982         if (line[0] == '@') {
1983                 if (ecbdata->diff_words)
1984                         diff_words_flush(ecbdata);
1985                 len = sane_truncate_line(ecbdata, line, len);
1986                 find_lno(line, ecbdata);
1987                 emit_hunk_header(ecbdata, line, len);
1988                 return;
1989         }
1990
1991         if (ecbdata->diff_words) {
1992                 enum diff_symbol s =
1993                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
1994                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
1995                 if (line[0] == '-') {
1996                         diff_words_append(line, len,
1997                                           &ecbdata->diff_words->minus);
1998                         return;
1999                 } else if (line[0] == '+') {
2000                         diff_words_append(line, len,
2001                                           &ecbdata->diff_words->plus);
2002                         return;
2003                 } else if (starts_with(line, "\\ ")) {
2004                         /*
2005                          * Eat the "no newline at eof" marker as if we
2006                          * saw a "+" or "-" line with nothing on it,
2007                          * and return without diff_words_flush() to
2008                          * defer processing. If this is the end of
2009                          * preimage, more "+" lines may come after it.
2010                          */
2011                         return;
2012                 }
2013                 diff_words_flush(ecbdata);
2014                 emit_diff_symbol(o, s, line, len, 0);
2015                 return;
2016         }
2017
2018         switch (line[0]) {
2019         case '+':
2020                 ecbdata->lno_in_postimage++;
2021                 emit_add_line(reset, ecbdata, line + 1, len - 1);
2022                 break;
2023         case '-':
2024                 ecbdata->lno_in_preimage++;
2025                 emit_del_line(reset, ecbdata, line + 1, len - 1);
2026                 break;
2027         case ' ':
2028                 ecbdata->lno_in_postimage++;
2029                 ecbdata->lno_in_preimage++;
2030                 emit_context_line(reset, ecbdata, line + 1, len - 1);
2031                 break;
2032         default:
2033                 /* incomplete line at the end */
2034                 ecbdata->lno_in_preimage++;
2035                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2036                                  line, len, 0);
2037                 break;
2038         }
2039 }
2040
2041 static void pprint_rename(struct strbuf *name, const char *a, const char *b)
2042 {
2043         const char *old_name = a;
2044         const char *new_name = b;
2045         int pfx_length, sfx_length;
2046         int pfx_adjust_for_slash;
2047         int len_a = strlen(a);
2048         int len_b = strlen(b);
2049         int a_midlen, b_midlen;
2050         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2051         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2052
2053         if (qlen_a || qlen_b) {
2054                 quote_c_style(a, name, NULL, 0);
2055                 strbuf_addstr(name, " => ");
2056                 quote_c_style(b, name, NULL, 0);
2057                 return;
2058         }
2059
2060         /* Find common prefix */
2061         pfx_length = 0;
2062         while (*old_name && *new_name && *old_name == *new_name) {
2063                 if (*old_name == '/')
2064                         pfx_length = old_name - a + 1;
2065                 old_name++;
2066                 new_name++;
2067         }
2068
2069         /* Find common suffix */
2070         old_name = a + len_a;
2071         new_name = b + len_b;
2072         sfx_length = 0;
2073         /*
2074          * If there is a common prefix, it must end in a slash.  In
2075          * that case we let this loop run 1 into the prefix to see the
2076          * same slash.
2077          *
2078          * If there is no common prefix, we cannot do this as it would
2079          * underrun the input strings.
2080          */
2081         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2082         while (a + pfx_length - pfx_adjust_for_slash <= old_name &&
2083                b + pfx_length - pfx_adjust_for_slash <= new_name &&
2084                *old_name == *new_name) {
2085                 if (*old_name == '/')
2086                         sfx_length = len_a - (old_name - a);
2087                 old_name--;
2088                 new_name--;
2089         }
2090
2091         /*
2092          * pfx{mid-a => mid-b}sfx
2093          * {pfx-a => pfx-b}sfx
2094          * pfx{sfx-a => sfx-b}
2095          * name-a => name-b
2096          */
2097         a_midlen = len_a - pfx_length - sfx_length;
2098         b_midlen = len_b - pfx_length - sfx_length;
2099         if (a_midlen < 0)
2100                 a_midlen = 0;
2101         if (b_midlen < 0)
2102                 b_midlen = 0;
2103
2104         strbuf_grow(name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2105         if (pfx_length + sfx_length) {
2106                 strbuf_add(name, a, pfx_length);
2107                 strbuf_addch(name, '{');
2108         }
2109         strbuf_add(name, a + pfx_length, a_midlen);
2110         strbuf_addstr(name, " => ");
2111         strbuf_add(name, b + pfx_length, b_midlen);
2112         if (pfx_length + sfx_length) {
2113                 strbuf_addch(name, '}');
2114                 strbuf_add(name, a + len_a - sfx_length, sfx_length);
2115         }
2116 }
2117
2118 struct diffstat_t {
2119         int nr;
2120         int alloc;
2121         struct diffstat_file {
2122                 char *from_name;
2123                 char *name;
2124                 char *print_name;
2125                 const char *comments;
2126                 unsigned is_unmerged:1;
2127                 unsigned is_binary:1;
2128                 unsigned is_renamed:1;
2129                 unsigned is_interesting:1;
2130                 uintmax_t added, deleted;
2131         } **files;
2132 };
2133
2134 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2135                                           const char *name_a,
2136                                           const char *name_b)
2137 {
2138         struct diffstat_file *x;
2139         x = xcalloc(1, sizeof(*x));
2140         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2141         diffstat->files[diffstat->nr++] = x;
2142         if (name_b) {
2143                 x->from_name = xstrdup(name_a);
2144                 x->name = xstrdup(name_b);
2145                 x->is_renamed = 1;
2146         }
2147         else {
2148                 x->from_name = NULL;
2149                 x->name = xstrdup(name_a);
2150         }
2151         return x;
2152 }
2153
2154 static void diffstat_consume(void *priv, char *line, unsigned long len)
2155 {
2156         struct diffstat_t *diffstat = priv;
2157         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2158
2159         if (line[0] == '+')
2160                 x->added++;
2161         else if (line[0] == '-')
2162                 x->deleted++;
2163 }
2164
2165 const char mime_boundary_leader[] = "------------";
2166
2167 static int scale_linear(int it, int width, int max_change)
2168 {
2169         if (!it)
2170                 return 0;
2171         /*
2172          * make sure that at least one '-' or '+' is printed if
2173          * there is any change to this path. The easiest way is to
2174          * scale linearly as if the alloted width is one column shorter
2175          * than it is, and then add 1 to the result.
2176          */
2177         return 1 + (it * (width - 1) / max_change);
2178 }
2179
2180 static void show_graph(struct strbuf *out, char ch, int cnt,
2181                        const char *set, const char *reset)
2182 {
2183         if (cnt <= 0)
2184                 return;
2185         strbuf_addstr(out, set);
2186         strbuf_addchars(out, ch, cnt);
2187         strbuf_addstr(out, reset);
2188 }
2189
2190 static void fill_print_name(struct diffstat_file *file)
2191 {
2192         struct strbuf pname = STRBUF_INIT;
2193
2194         if (file->print_name)
2195                 return;
2196
2197         if (file->is_renamed)
2198                 pprint_rename(&pname, file->from_name, file->name);
2199         else
2200                 quote_c_style(file->name, &pname, NULL, 0);
2201
2202         if (file->comments)
2203                 strbuf_addf(&pname, " (%s)", file->comments);
2204
2205         file->print_name = strbuf_detach(&pname, NULL);
2206 }
2207
2208 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2209                 int files, int insertions, int deletions)
2210 {
2211         struct strbuf sb = STRBUF_INIT;
2212
2213         if (!files) {
2214                 assert(insertions == 0 && deletions == 0);
2215                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2216                                  NULL, 0, 0);
2217                 return;
2218         }
2219
2220         strbuf_addf(&sb,
2221                     (files == 1) ? " %d file changed" : " %d files changed",
2222                     files);
2223
2224         /*
2225          * For binary diff, the caller may want to print "x files
2226          * changed" with insertions == 0 && deletions == 0.
2227          *
2228          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2229          * is probably less confusing (i.e skip over "2 files changed
2230          * but nothing about added/removed lines? Is this a bug in Git?").
2231          */
2232         if (insertions || deletions == 0) {
2233                 strbuf_addf(&sb,
2234                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2235                             insertions);
2236         }
2237
2238         if (deletions || insertions == 0) {
2239                 strbuf_addf(&sb,
2240                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2241                             deletions);
2242         }
2243         strbuf_addch(&sb, '\n');
2244         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2245                          sb.buf, sb.len, 0);
2246         strbuf_release(&sb);
2247 }
2248
2249 void print_stat_summary(FILE *fp, int files,
2250                         int insertions, int deletions)
2251 {
2252         struct diff_options o;
2253         memset(&o, 0, sizeof(o));
2254         o.file = fp;
2255
2256         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2257 }
2258
2259 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2260 {
2261         int i, len, add, del, adds = 0, dels = 0;
2262         uintmax_t max_change = 0, max_len = 0;
2263         int total_files = data->nr, count;
2264         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2265         const char *reset, *add_c, *del_c;
2266         int extra_shown = 0;
2267         const char *line_prefix = diff_line_prefix(options);
2268         struct strbuf out = STRBUF_INIT;
2269
2270         if (data->nr == 0)
2271                 return;
2272
2273         count = options->stat_count ? options->stat_count : data->nr;
2274
2275         reset = diff_get_color_opt(options, DIFF_RESET);
2276         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2277         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2278
2279         /*
2280          * Find the longest filename and max number of changes
2281          */
2282         for (i = 0; (i < count) && (i < data->nr); i++) {
2283                 struct diffstat_file *file = data->files[i];
2284                 uintmax_t change = file->added + file->deleted;
2285
2286                 if (!file->is_interesting && (change == 0)) {
2287                         count++; /* not shown == room for one more */
2288                         continue;
2289                 }
2290                 fill_print_name(file);
2291                 len = strlen(file->print_name);
2292                 if (max_len < len)
2293                         max_len = len;
2294
2295                 if (file->is_unmerged) {
2296                         /* "Unmerged" is 8 characters */
2297                         bin_width = bin_width < 8 ? 8 : bin_width;
2298                         continue;
2299                 }
2300                 if (file->is_binary) {
2301                         /* "Bin XXX -> YYY bytes" */
2302                         int w = 14 + decimal_width(file->added)
2303                                 + decimal_width(file->deleted);
2304                         bin_width = bin_width < w ? w : bin_width;
2305                         /* Display change counts aligned with "Bin" */
2306                         number_width = 3;
2307                         continue;
2308                 }
2309
2310                 if (max_change < change)
2311                         max_change = change;
2312         }
2313         count = i; /* where we can stop scanning in data->files[] */
2314
2315         /*
2316          * We have width = stat_width or term_columns() columns total.
2317          * We want a maximum of min(max_len, stat_name_width) for the name part.
2318          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2319          * We also need 1 for " " and 4 + decimal_width(max_change)
2320          * for " | NNNN " and one the empty column at the end, altogether
2321          * 6 + decimal_width(max_change).
2322          *
2323          * If there's not enough space, we will use the smaller of
2324          * stat_name_width (if set) and 5/8*width for the filename,
2325          * and the rest for constant elements + graph part, but no more
2326          * than stat_graph_width for the graph part.
2327          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2328          * for the standard terminal size).
2329          *
2330          * In other words: stat_width limits the maximum width, and
2331          * stat_name_width fixes the maximum width of the filename,
2332          * and is also used to divide available columns if there
2333          * aren't enough.
2334          *
2335          * Binary files are displayed with "Bin XXX -> YYY bytes"
2336          * instead of the change count and graph. This part is treated
2337          * similarly to the graph part, except that it is not
2338          * "scaled". If total width is too small to accommodate the
2339          * guaranteed minimum width of the filename part and the
2340          * separators and this message, this message will "overflow"
2341          * making the line longer than the maximum width.
2342          */
2343
2344         if (options->stat_width == -1)
2345                 width = term_columns() - strlen(line_prefix);
2346         else
2347                 width = options->stat_width ? options->stat_width : 80;
2348         number_width = decimal_width(max_change) > number_width ?
2349                 decimal_width(max_change) : number_width;
2350
2351         if (options->stat_graph_width == -1)
2352                 options->stat_graph_width = diff_stat_graph_width;
2353
2354         /*
2355          * Guarantee 3/8*16==6 for the graph part
2356          * and 5/8*16==10 for the filename part
2357          */
2358         if (width < 16 + 6 + number_width)
2359                 width = 16 + 6 + number_width;
2360
2361         /*
2362          * First assign sizes that are wanted, ignoring available width.
2363          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2364          * starting from "XXX" should fit in graph_width.
2365          */
2366         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2367         if (options->stat_graph_width &&
2368             options->stat_graph_width < graph_width)
2369                 graph_width = options->stat_graph_width;
2370
2371         name_width = (options->stat_name_width > 0 &&
2372                       options->stat_name_width < max_len) ?
2373                 options->stat_name_width : max_len;
2374
2375         /*
2376          * Adjust adjustable widths not to exceed maximum width
2377          */
2378         if (name_width + number_width + 6 + graph_width > width) {
2379                 if (graph_width > width * 3/8 - number_width - 6) {
2380                         graph_width = width * 3/8 - number_width - 6;
2381                         if (graph_width < 6)
2382                                 graph_width = 6;
2383                 }
2384
2385                 if (options->stat_graph_width &&
2386                     graph_width > options->stat_graph_width)
2387                         graph_width = options->stat_graph_width;
2388                 if (name_width > width - number_width - 6 - graph_width)
2389                         name_width = width - number_width - 6 - graph_width;
2390                 else
2391                         graph_width = width - number_width - 6 - name_width;
2392         }
2393
2394         /*
2395          * From here name_width is the width of the name area,
2396          * and graph_width is the width of the graph area.
2397          * max_change is used to scale graph properly.
2398          */
2399         for (i = 0; i < count; i++) {
2400                 const char *prefix = "";
2401                 struct diffstat_file *file = data->files[i];
2402                 char *name = file->print_name;
2403                 uintmax_t added = file->added;
2404                 uintmax_t deleted = file->deleted;
2405                 int name_len;
2406
2407                 if (!file->is_interesting && (added + deleted == 0))
2408                         continue;
2409
2410                 /*
2411                  * "scale" the filename
2412                  */
2413                 len = name_width;
2414                 name_len = strlen(name);
2415                 if (name_width < name_len) {
2416                         char *slash;
2417                         prefix = "...";
2418                         len -= 3;
2419                         name += name_len - len;
2420                         slash = strchr(name, '/');
2421                         if (slash)
2422                                 name = slash;
2423                 }
2424
2425                 if (file->is_binary) {
2426                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2427                         strbuf_addf(&out, " %*s", number_width, "Bin");
2428                         if (!added && !deleted) {
2429                                 strbuf_addch(&out, '\n');
2430                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2431                                                  out.buf, out.len, 0);
2432                                 strbuf_reset(&out);
2433                                 continue;
2434                         }
2435                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2436                                 del_c, deleted, reset);
2437                         strbuf_addstr(&out, " -> ");
2438                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2439                                 add_c, added, reset);
2440                         strbuf_addstr(&out, " bytes\n");
2441                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2442                                          out.buf, out.len, 0);
2443                         strbuf_reset(&out);
2444                         continue;
2445                 }
2446                 else if (file->is_unmerged) {
2447                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2448                         strbuf_addstr(&out, " Unmerged\n");
2449                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2450                                          out.buf, out.len, 0);
2451                         strbuf_reset(&out);
2452                         continue;
2453                 }
2454
2455                 /*
2456                  * scale the add/delete
2457                  */
2458                 add = added;
2459                 del = deleted;
2460
2461                 if (graph_width <= max_change) {
2462                         int total = scale_linear(add + del, graph_width, max_change);
2463                         if (total < 2 && add && del)
2464                                 /* width >= 2 due to the sanity check */
2465                                 total = 2;
2466                         if (add < del) {
2467                                 add = scale_linear(add, graph_width, max_change);
2468                                 del = total - add;
2469                         } else {
2470                                 del = scale_linear(del, graph_width, max_change);
2471                                 add = total - del;
2472                         }
2473                 }
2474                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2475                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2476                         number_width, added + deleted,
2477                         added + deleted ? " " : "");
2478                 show_graph(&out, '+', add, add_c, reset);
2479                 show_graph(&out, '-', del, del_c, reset);
2480                 strbuf_addch(&out, '\n');
2481                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2482                                  out.buf, out.len, 0);
2483                 strbuf_reset(&out);
2484         }
2485
2486         for (i = 0; i < data->nr; i++) {
2487                 struct diffstat_file *file = data->files[i];
2488                 uintmax_t added = file->added;
2489                 uintmax_t deleted = file->deleted;
2490
2491                 if (file->is_unmerged ||
2492                     (!file->is_interesting && (added + deleted == 0))) {
2493                         total_files--;
2494                         continue;
2495                 }
2496
2497                 if (!file->is_binary) {
2498                         adds += added;
2499                         dels += deleted;
2500                 }
2501                 if (i < count)
2502                         continue;
2503                 if (!extra_shown)
2504                         emit_diff_symbol(options,
2505                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2506                                          NULL, 0, 0);
2507                 extra_shown = 1;
2508         }
2509
2510         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2511         strbuf_release(&out);
2512 }
2513
2514 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2515 {
2516         int i, adds = 0, dels = 0, total_files = data->nr;
2517
2518         if (data->nr == 0)
2519                 return;
2520
2521         for (i = 0; i < data->nr; i++) {
2522                 int added = data->files[i]->added;
2523                 int deleted = data->files[i]->deleted;
2524
2525                 if (data->files[i]->is_unmerged ||
2526                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2527                         total_files--;
2528                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2529                         adds += added;
2530                         dels += deleted;
2531                 }
2532         }
2533         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2534 }
2535
2536 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2537 {
2538         int i;
2539
2540         if (data->nr == 0)
2541                 return;
2542
2543         for (i = 0; i < data->nr; i++) {
2544                 struct diffstat_file *file = data->files[i];
2545
2546                 fprintf(options->file, "%s", diff_line_prefix(options));
2547
2548                 if (file->is_binary)
2549                         fprintf(options->file, "-\t-\t");
2550                 else
2551                         fprintf(options->file,
2552                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2553                                 file->added, file->deleted);
2554                 if (options->line_termination) {
2555                         fill_print_name(file);
2556                         if (!file->is_renamed)
2557                                 write_name_quoted(file->name, options->file,
2558                                                   options->line_termination);
2559                         else {
2560                                 fputs(file->print_name, options->file);
2561                                 putc(options->line_termination, options->file);
2562                         }
2563                 } else {
2564                         if (file->is_renamed) {
2565                                 putc('\0', options->file);
2566                                 write_name_quoted(file->from_name, options->file, '\0');
2567                         }
2568                         write_name_quoted(file->name, options->file, '\0');
2569                 }
2570         }
2571 }
2572
2573 struct dirstat_file {
2574         const char *name;
2575         unsigned long changed;
2576 };
2577
2578 struct dirstat_dir {
2579         struct dirstat_file *files;
2580         int alloc, nr, permille, cumulative;
2581 };
2582
2583 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2584                 unsigned long changed, const char *base, int baselen)
2585 {
2586         unsigned long sum_changes = 0;
2587         unsigned int sources = 0;
2588         const char *line_prefix = diff_line_prefix(opt);
2589
2590         while (dir->nr) {
2591                 struct dirstat_file *f = dir->files;
2592                 int namelen = strlen(f->name);
2593                 unsigned long changes;
2594                 char *slash;
2595
2596                 if (namelen < baselen)
2597                         break;
2598                 if (memcmp(f->name, base, baselen))
2599                         break;
2600                 slash = strchr(f->name + baselen, '/');
2601                 if (slash) {
2602                         int newbaselen = slash + 1 - f->name;
2603                         changes = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2604                         sources++;
2605                 } else {
2606                         changes = f->changed;
2607                         dir->files++;
2608                         dir->nr--;
2609                         sources += 2;
2610                 }
2611                 sum_changes += changes;
2612         }
2613
2614         /*
2615          * We don't report dirstat's for
2616          *  - the top level
2617          *  - or cases where everything came from a single directory
2618          *    under this directory (sources == 1).
2619          */
2620         if (baselen && sources != 1) {
2621                 if (sum_changes) {
2622                         int permille = sum_changes * 1000 / changed;
2623                         if (permille >= dir->permille) {
2624                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2625                                         permille / 10, permille % 10, baselen, base);
2626                                 if (!dir->cumulative)
2627                                         return 0;
2628                         }
2629                 }
2630         }
2631         return sum_changes;
2632 }
2633
2634 static int dirstat_compare(const void *_a, const void *_b)
2635 {
2636         const struct dirstat_file *a = _a;
2637         const struct dirstat_file *b = _b;
2638         return strcmp(a->name, b->name);
2639 }
2640
2641 static void show_dirstat(struct diff_options *options)
2642 {
2643         int i;
2644         unsigned long changed;
2645         struct dirstat_dir dir;
2646         struct diff_queue_struct *q = &diff_queued_diff;
2647
2648         dir.files = NULL;
2649         dir.alloc = 0;
2650         dir.nr = 0;
2651         dir.permille = options->dirstat_permille;
2652         dir.cumulative = options->flags.dirstat_cumulative;
2653
2654         changed = 0;
2655         for (i = 0; i < q->nr; i++) {
2656                 struct diff_filepair *p = q->queue[i];
2657                 const char *name;
2658                 unsigned long copied, added, damage;
2659                 int content_changed;
2660
2661                 name = p->two->path ? p->two->path : p->one->path;
2662
2663                 if (p->one->oid_valid && p->two->oid_valid)
2664                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
2665                 else
2666                         content_changed = 1;
2667
2668                 if (!content_changed) {
2669                         /*
2670                          * The SHA1 has not changed, so pre-/post-content is
2671                          * identical. We can therefore skip looking at the
2672                          * file contents altogether.
2673                          */
2674                         damage = 0;
2675                         goto found_damage;
2676                 }
2677
2678                 if (options->flags.dirstat_by_file) {
2679                         /*
2680                          * In --dirstat-by-file mode, we don't really need to
2681                          * look at the actual file contents at all.
2682                          * The fact that the SHA1 changed is enough for us to
2683                          * add this file to the list of results
2684                          * (with each file contributing equal damage).
2685                          */
2686                         damage = 1;
2687                         goto found_damage;
2688                 }
2689
2690                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2691                         diff_populate_filespec(p->one, 0);
2692                         diff_populate_filespec(p->two, 0);
2693                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2694                                                &copied, &added);
2695                         diff_free_filespec_data(p->one);
2696                         diff_free_filespec_data(p->two);
2697                 } else if (DIFF_FILE_VALID(p->one)) {
2698                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2699                         copied = added = 0;
2700                         diff_free_filespec_data(p->one);
2701                 } else if (DIFF_FILE_VALID(p->two)) {
2702                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2703                         copied = 0;
2704                         added = p->two->size;
2705                         diff_free_filespec_data(p->two);
2706                 } else
2707                         continue;
2708
2709                 /*
2710                  * Original minus copied is the removed material,
2711                  * added is the new material.  They are both damages
2712                  * made to the preimage.
2713                  * If the resulting damage is zero, we know that
2714                  * diffcore_count_changes() considers the two entries to
2715                  * be identical, but since content_changed is true, we
2716                  * know that there must have been _some_ kind of change,
2717                  * so we force all entries to have damage > 0.
2718                  */
2719                 damage = (p->one->size - copied) + added;
2720                 if (!damage)
2721                         damage = 1;
2722
2723 found_damage:
2724                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2725                 dir.files[dir.nr].name = name;
2726                 dir.files[dir.nr].changed = damage;
2727                 changed += damage;
2728                 dir.nr++;
2729         }
2730
2731         /* This can happen even with many files, if everything was renames */
2732         if (!changed)
2733                 return;
2734
2735         /* Show all directories with more than x% of the changes */
2736         QSORT(dir.files, dir.nr, dirstat_compare);
2737         gather_dirstat(options, &dir, changed, "", 0);
2738 }
2739
2740 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2741 {
2742         int i;
2743         unsigned long changed;
2744         struct dirstat_dir dir;
2745
2746         if (data->nr == 0)
2747                 return;
2748
2749         dir.files = NULL;
2750         dir.alloc = 0;
2751         dir.nr = 0;
2752         dir.permille = options->dirstat_permille;
2753         dir.cumulative = options->flags.dirstat_cumulative;
2754
2755         changed = 0;
2756         for (i = 0; i < data->nr; i++) {
2757                 struct diffstat_file *file = data->files[i];
2758                 unsigned long damage = file->added + file->deleted;
2759                 if (file->is_binary)
2760                         /*
2761                          * binary files counts bytes, not lines. Must find some
2762                          * way to normalize binary bytes vs. textual lines.
2763                          * The following heuristic assumes that there are 64
2764                          * bytes per "line".
2765                          * This is stupid and ugly, but very cheap...
2766                          */
2767                         damage = DIV_ROUND_UP(damage, 64);
2768                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2769                 dir.files[dir.nr].name = file->name;
2770                 dir.files[dir.nr].changed = damage;
2771                 changed += damage;
2772                 dir.nr++;
2773         }
2774
2775         /* This can happen even with many files, if everything was renames */
2776         if (!changed)
2777                 return;
2778
2779         /* Show all directories with more than x% of the changes */
2780         QSORT(dir.files, dir.nr, dirstat_compare);
2781         gather_dirstat(options, &dir, changed, "", 0);
2782 }
2783
2784 static void free_diffstat_info(struct diffstat_t *diffstat)
2785 {
2786         int i;
2787         for (i = 0; i < diffstat->nr; i++) {
2788                 struct diffstat_file *f = diffstat->files[i];
2789                 free(f->print_name);
2790                 free(f->name);
2791                 free(f->from_name);
2792                 free(f);
2793         }
2794         free(diffstat->files);
2795 }
2796
2797 struct checkdiff_t {
2798         const char *filename;
2799         int lineno;
2800         int conflict_marker_size;
2801         struct diff_options *o;
2802         unsigned ws_rule;
2803         unsigned status;
2804 };
2805
2806 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2807 {
2808         char firstchar;
2809         int cnt;
2810
2811         if (len < marker_size + 1)
2812                 return 0;
2813         firstchar = line[0];
2814         switch (firstchar) {
2815         case '=': case '>': case '<': case '|':
2816                 break;
2817         default:
2818                 return 0;
2819         }
2820         for (cnt = 1; cnt < marker_size; cnt++)
2821                 if (line[cnt] != firstchar)
2822                         return 0;
2823         /* line[1] thru line[marker_size-1] are same as firstchar */
2824         if (len < marker_size + 1 || !isspace(line[marker_size]))
2825                 return 0;
2826         return 1;
2827 }
2828
2829 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2830 {
2831         struct checkdiff_t *data = priv;
2832         int marker_size = data->conflict_marker_size;
2833         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2834         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2835         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2836         char *err;
2837         const char *line_prefix;
2838
2839         assert(data->o);
2840         line_prefix = diff_line_prefix(data->o);
2841
2842         if (line[0] == '+') {
2843                 unsigned bad;
2844                 data->lineno++;
2845                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2846                         data->status |= 1;
2847                         fprintf(data->o->file,
2848                                 "%s%s:%d: leftover conflict marker\n",
2849                                 line_prefix, data->filename, data->lineno);
2850                 }
2851                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2852                 if (!bad)
2853                         return;
2854                 data->status |= bad;
2855                 err = whitespace_error_string(bad);
2856                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2857                         line_prefix, data->filename, data->lineno, err);
2858                 free(err);
2859                 emit_line(data->o, set, reset, line, 1);
2860                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2861                               data->o->file, set, reset, ws);
2862         } else if (line[0] == ' ') {
2863                 data->lineno++;
2864         } else if (line[0] == '@') {
2865                 char *plus = strchr(line, '+');
2866                 if (plus)
2867                         data->lineno = strtol(plus, NULL, 10) - 1;
2868                 else
2869                         die("invalid diff");
2870         }
2871 }
2872
2873 static unsigned char *deflate_it(char *data,
2874                                  unsigned long size,
2875                                  unsigned long *result_size)
2876 {
2877         int bound;
2878         unsigned char *deflated;
2879         git_zstream stream;
2880
2881         git_deflate_init(&stream, zlib_compression_level);
2882         bound = git_deflate_bound(&stream, size);
2883         deflated = xmalloc(bound);
2884         stream.next_out = deflated;
2885         stream.avail_out = bound;
2886
2887         stream.next_in = (unsigned char *)data;
2888         stream.avail_in = size;
2889         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2890                 ; /* nothing */
2891         git_deflate_end(&stream);
2892         *result_size = stream.total_out;
2893         return deflated;
2894 }
2895
2896 static void emit_binary_diff_body(struct diff_options *o,
2897                                   mmfile_t *one, mmfile_t *two)
2898 {
2899         void *cp;
2900         void *delta;
2901         void *deflated;
2902         void *data;
2903         unsigned long orig_size;
2904         unsigned long delta_size;
2905         unsigned long deflate_size;
2906         unsigned long data_size;
2907
2908         /* We could do deflated delta, or we could do just deflated two,
2909          * whichever is smaller.
2910          */
2911         delta = NULL;
2912         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2913         if (one->size && two->size) {
2914                 delta = diff_delta(one->ptr, one->size,
2915                                    two->ptr, two->size,
2916                                    &delta_size, deflate_size);
2917                 if (delta) {
2918                         void *to_free = delta;
2919                         orig_size = delta_size;
2920                         delta = deflate_it(delta, delta_size, &delta_size);
2921                         free(to_free);
2922                 }
2923         }
2924
2925         if (delta && delta_size < deflate_size) {
2926                 char *s = xstrfmt("%lu", orig_size);
2927                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
2928                                  s, strlen(s), 0);
2929                 free(s);
2930                 free(deflated);
2931                 data = delta;
2932                 data_size = delta_size;
2933         } else {
2934                 char *s = xstrfmt("%lu", two->size);
2935                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
2936                                  s, strlen(s), 0);
2937                 free(s);
2938                 free(delta);
2939                 data = deflated;
2940                 data_size = deflate_size;
2941         }
2942
2943         /* emit data encoded in base85 */
2944         cp = data;
2945         while (data_size) {
2946                 int len;
2947                 int bytes = (52 < data_size) ? 52 : data_size;
2948                 char line[71];
2949                 data_size -= bytes;
2950                 if (bytes <= 26)
2951                         line[0] = bytes + 'A' - 1;
2952                 else
2953                         line[0] = bytes - 26 + 'a' - 1;
2954                 encode_85(line + 1, cp, bytes);
2955                 cp = (char *) cp + bytes;
2956
2957                 len = strlen(line);
2958                 line[len++] = '\n';
2959                 line[len] = '\0';
2960
2961                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
2962                                  line, len, 0);
2963         }
2964         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
2965         free(data);
2966 }
2967
2968 static void emit_binary_diff(struct diff_options *o,
2969                              mmfile_t *one, mmfile_t *two)
2970 {
2971         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
2972         emit_binary_diff_body(o, one, two);
2973         emit_binary_diff_body(o, two, one);
2974 }
2975
2976 int diff_filespec_is_binary(struct diff_filespec *one)
2977 {
2978         if (one->is_binary == -1) {
2979                 diff_filespec_load_driver(one);
2980                 if (one->driver->binary != -1)
2981                         one->is_binary = one->driver->binary;
2982                 else {
2983                         if (!one->data && DIFF_FILE_VALID(one))
2984                                 diff_populate_filespec(one, CHECK_BINARY);
2985                         if (one->is_binary == -1 && one->data)
2986                                 one->is_binary = buffer_is_binary(one->data,
2987                                                 one->size);
2988                         if (one->is_binary == -1)
2989                                 one->is_binary = 0;
2990                 }
2991         }
2992         return one->is_binary;
2993 }
2994
2995 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2996 {
2997         diff_filespec_load_driver(one);
2998         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2999 }
3000
3001 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3002 {
3003         if (!options->a_prefix)
3004                 options->a_prefix = a;
3005         if (!options->b_prefix)
3006                 options->b_prefix = b;
3007 }
3008
3009 struct userdiff_driver *get_textconv(struct diff_filespec *one)
3010 {
3011         if (!DIFF_FILE_VALID(one))
3012                 return NULL;
3013
3014         diff_filespec_load_driver(one);
3015         return userdiff_get_textconv(one->driver);
3016 }
3017
3018 static void builtin_diff(const char *name_a,
3019                          const char *name_b,
3020                          struct diff_filespec *one,
3021                          struct diff_filespec *two,
3022                          const char *xfrm_msg,
3023                          int must_show_header,
3024                          struct diff_options *o,
3025                          int complete_rewrite)
3026 {
3027         mmfile_t mf1, mf2;
3028         const char *lbl[2];
3029         char *a_one, *b_two;
3030         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3031         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3032         const char *a_prefix, *b_prefix;
3033         struct userdiff_driver *textconv_one = NULL;
3034         struct userdiff_driver *textconv_two = NULL;
3035         struct strbuf header = STRBUF_INIT;
3036         const char *line_prefix = diff_line_prefix(o);
3037
3038         diff_set_mnemonic_prefix(o, "a/", "b/");
3039         if (o->flags.reverse_diff) {
3040                 a_prefix = o->b_prefix;
3041                 b_prefix = o->a_prefix;
3042         } else {
3043                 a_prefix = o->a_prefix;
3044                 b_prefix = o->b_prefix;
3045         }
3046
3047         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3048             (!one->mode || S_ISGITLINK(one->mode)) &&
3049             (!two->mode || S_ISGITLINK(two->mode))) {
3050                 show_submodule_summary(o, one->path ? one->path : two->path,
3051                                 &one->oid, &two->oid,
3052                                 two->dirty_submodule);
3053                 return;
3054         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3055                    (!one->mode || S_ISGITLINK(one->mode)) &&
3056                    (!two->mode || S_ISGITLINK(two->mode))) {
3057                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3058                                 &one->oid, &two->oid,
3059                                 two->dirty_submodule);
3060                 return;
3061         }
3062
3063         if (o->flags.allow_textconv) {
3064                 textconv_one = get_textconv(one);
3065                 textconv_two = get_textconv(two);
3066         }
3067
3068         /* Never use a non-valid filename anywhere if at all possible */
3069         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3070         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3071
3072         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3073         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3074         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3075         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3076         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3077         if (lbl[0][0] == '/') {
3078                 /* /dev/null */
3079                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3080                 if (xfrm_msg)
3081                         strbuf_addstr(&header, xfrm_msg);
3082                 must_show_header = 1;
3083         }
3084         else if (lbl[1][0] == '/') {
3085                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3086                 if (xfrm_msg)
3087                         strbuf_addstr(&header, xfrm_msg);
3088                 must_show_header = 1;
3089         }
3090         else {
3091                 if (one->mode != two->mode) {
3092                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3093                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3094                         must_show_header = 1;
3095                 }
3096                 if (xfrm_msg)
3097                         strbuf_addstr(&header, xfrm_msg);
3098
3099                 /*
3100                  * we do not run diff between different kind
3101                  * of objects.
3102                  */
3103                 if ((one->mode ^ two->mode) & S_IFMT)
3104                         goto free_ab_and_return;
3105                 if (complete_rewrite &&
3106                     (textconv_one || !diff_filespec_is_binary(one)) &&
3107                     (textconv_two || !diff_filespec_is_binary(two))) {
3108                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3109                                          header.buf, header.len, 0);
3110                         strbuf_reset(&header);
3111                         emit_rewrite_diff(name_a, name_b, one, two,
3112                                                 textconv_one, textconv_two, o);
3113                         o->found_changes = 1;
3114                         goto free_ab_and_return;
3115                 }
3116         }
3117
3118         if (o->irreversible_delete && lbl[1][0] == '/') {
3119                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3120                                  header.len, 0);
3121                 strbuf_reset(&header);
3122                 goto free_ab_and_return;
3123         } else if (!o->flags.text &&
3124             ( (!textconv_one && diff_filespec_is_binary(one)) ||
3125               (!textconv_two && diff_filespec_is_binary(two)) )) {
3126                 struct strbuf sb = STRBUF_INIT;
3127                 if (!one->data && !two->data &&
3128                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3129                     !o->flags.binary) {
3130                         if (!oidcmp(&one->oid, &two->oid)) {
3131                                 if (must_show_header)
3132                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3133                                                          header.buf, header.len,
3134                                                          0);
3135                                 goto free_ab_and_return;
3136                         }
3137                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3138                                          header.buf, header.len, 0);
3139                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3140                                     diff_line_prefix(o), lbl[0], lbl[1]);
3141                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3142                                          sb.buf, sb.len, 0);
3143                         strbuf_release(&sb);
3144                         goto free_ab_and_return;
3145                 }
3146                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3147                         die("unable to read files to diff");
3148                 /* Quite common confusing case */
3149                 if (mf1.size == mf2.size &&
3150                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3151                         if (must_show_header)
3152                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3153                                                  header.buf, header.len, 0);
3154                         goto free_ab_and_return;
3155                 }
3156                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3157                 strbuf_reset(&header);
3158                 if (o->flags.binary)
3159                         emit_binary_diff(o, &mf1, &mf2);
3160                 else {
3161                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3162                                     diff_line_prefix(o), lbl[0], lbl[1]);
3163                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3164                                          sb.buf, sb.len, 0);
3165                         strbuf_release(&sb);
3166                 }
3167                 o->found_changes = 1;
3168         } else {
3169                 /* Crazy xdl interfaces.. */
3170                 const char *diffopts = getenv("GIT_DIFF_OPTS");
3171                 const char *v;
3172                 xpparam_t xpp;
3173                 xdemitconf_t xecfg;
3174                 struct emit_callback ecbdata;
3175                 const struct userdiff_funcname *pe;
3176
3177                 if (must_show_header) {
3178                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3179                                          header.buf, header.len, 0);
3180                         strbuf_reset(&header);
3181                 }
3182
3183                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
3184                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
3185
3186                 pe = diff_funcname_pattern(one);
3187                 if (!pe)
3188                         pe = diff_funcname_pattern(two);
3189
3190                 memset(&xpp, 0, sizeof(xpp));
3191                 memset(&xecfg, 0, sizeof(xecfg));
3192                 memset(&ecbdata, 0, sizeof(ecbdata));
3193                 ecbdata.label_path = lbl;
3194                 ecbdata.color_diff = want_color(o->use_color);
3195                 ecbdata.ws_rule = whitespace_rule(name_b);
3196                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3197                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3198                 ecbdata.opt = o;
3199                 ecbdata.header = header.len ? &header : NULL;
3200                 xpp.flags = o->xdl_opts;
3201                 xpp.anchors = o->anchors;
3202                 xpp.anchors_nr = o->anchors_nr;
3203                 xecfg.ctxlen = o->context;
3204                 xecfg.interhunkctxlen = o->interhunkcontext;
3205                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3206                 if (o->flags.funccontext)
3207                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3208                 if (pe)
3209                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3210                 if (!diffopts)
3211                         ;
3212                 else if (skip_prefix(diffopts, "--unified=", &v))
3213                         xecfg.ctxlen = strtoul(v, NULL, 10);
3214                 else if (skip_prefix(diffopts, "-u", &v))
3215                         xecfg.ctxlen = strtoul(v, NULL, 10);
3216                 if (o->word_diff)
3217                         init_diff_words_data(&ecbdata, o, one, two);
3218                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
3219                                   &xpp, &xecfg))
3220                         die("unable to generate diff for %s", one->path);
3221                 if (o->word_diff)
3222                         free_diff_words_data(&ecbdata);
3223                 if (textconv_one)
3224                         free(mf1.ptr);
3225                 if (textconv_two)
3226                         free(mf2.ptr);
3227                 xdiff_clear_find_func(&xecfg);
3228         }
3229
3230  free_ab_and_return:
3231         strbuf_release(&header);
3232         diff_free_filespec_data(one);
3233         diff_free_filespec_data(two);
3234         free(a_one);
3235         free(b_two);
3236         return;
3237 }
3238
3239 static char *get_compact_summary(const struct diff_filepair *p, int is_renamed)
3240 {
3241         if (!is_renamed) {
3242                 if (p->status == DIFF_STATUS_ADDED) {
3243                         if (S_ISLNK(p->two->mode))
3244                                 return "new +l";
3245                         else if ((p->two->mode & 0777) == 0755)
3246                                 return "new +x";
3247                         else
3248                                 return "new";
3249                 } else if (p->status == DIFF_STATUS_DELETED)
3250                         return "gone";
3251         }
3252         if (S_ISLNK(p->one->mode) && !S_ISLNK(p->two->mode))
3253                 return "mode -l";
3254         else if (!S_ISLNK(p->one->mode) && S_ISLNK(p->two->mode))
3255                 return "mode +l";
3256         else if ((p->one->mode & 0777) == 0644 &&
3257                  (p->two->mode & 0777) == 0755)
3258                 return "mode +x";
3259         else if ((p->one->mode & 0777) == 0755 &&
3260                  (p->two->mode & 0777) == 0644)
3261                 return "mode -x";
3262         return NULL;
3263 }
3264
3265 static void builtin_diffstat(const char *name_a, const char *name_b,
3266                              struct diff_filespec *one,
3267                              struct diff_filespec *two,
3268                              struct diffstat_t *diffstat,
3269                              struct diff_options *o,
3270                              struct diff_filepair *p)
3271 {
3272         mmfile_t mf1, mf2;
3273         struct diffstat_file *data;
3274         int same_contents;
3275         int complete_rewrite = 0;
3276
3277         if (!DIFF_PAIR_UNMERGED(p)) {
3278                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3279                         complete_rewrite = 1;
3280         }
3281
3282         data = diffstat_add(diffstat, name_a, name_b);
3283         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3284         if (o->flags.stat_with_summary)
3285                 data->comments = get_compact_summary(p, data->is_renamed);
3286
3287         if (!one || !two) {
3288                 data->is_unmerged = 1;
3289                 return;
3290         }
3291
3292         same_contents = !oidcmp(&one->oid, &two->oid);
3293
3294         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
3295                 data->is_binary = 1;
3296                 if (same_contents) {
3297                         data->added = 0;
3298                         data->deleted = 0;
3299                 } else {
3300                         data->added = diff_filespec_size(two);
3301                         data->deleted = diff_filespec_size(one);
3302                 }
3303         }
3304
3305         else if (complete_rewrite) {
3306                 diff_populate_filespec(one, 0);
3307                 diff_populate_filespec(two, 0);
3308                 data->deleted = count_lines(one->data, one->size);
3309                 data->added = count_lines(two->data, two->size);
3310         }
3311
3312         else if (!same_contents) {
3313                 /* Crazy xdl interfaces.. */
3314                 xpparam_t xpp;
3315                 xdemitconf_t xecfg;
3316
3317                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3318                         die("unable to read files to diff");
3319
3320                 memset(&xpp, 0, sizeof(xpp));
3321                 memset(&xecfg, 0, sizeof(xecfg));
3322                 xpp.flags = o->xdl_opts;
3323                 xpp.anchors = o->anchors;
3324                 xpp.anchors_nr = o->anchors_nr;
3325                 xecfg.ctxlen = o->context;
3326                 xecfg.interhunkctxlen = o->interhunkcontext;
3327                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
3328                                   &xpp, &xecfg))
3329                         die("unable to generate diffstat for %s", one->path);
3330         }
3331
3332         diff_free_filespec_data(one);
3333         diff_free_filespec_data(two);
3334 }
3335
3336 static void builtin_checkdiff(const char *name_a, const char *name_b,
3337                               const char *attr_path,
3338                               struct diff_filespec *one,
3339                               struct diff_filespec *two,
3340                               struct diff_options *o)
3341 {
3342         mmfile_t mf1, mf2;
3343         struct checkdiff_t data;
3344
3345         if (!two)
3346                 return;
3347
3348         memset(&data, 0, sizeof(data));
3349         data.filename = name_b ? name_b : name_a;
3350         data.lineno = 0;
3351         data.o = o;
3352         data.ws_rule = whitespace_rule(attr_path);
3353         data.conflict_marker_size = ll_merge_marker_size(attr_path);
3354
3355         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3356                 die("unable to read files to diff");
3357
3358         /*
3359          * All the other codepaths check both sides, but not checking
3360          * the "old" side here is deliberate.  We are checking the newly
3361          * introduced changes, and as long as the "new" side is text, we
3362          * can and should check what it introduces.
3363          */
3364         if (diff_filespec_is_binary(two))
3365                 goto free_and_return;
3366         else {
3367                 /* Crazy xdl interfaces.. */
3368                 xpparam_t xpp;
3369                 xdemitconf_t xecfg;
3370
3371                 memset(&xpp, 0, sizeof(xpp));
3372                 memset(&xecfg, 0, sizeof(xecfg));
3373                 xecfg.ctxlen = 1; /* at least one context line */
3374                 xpp.flags = 0;
3375                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
3376                                   &xpp, &xecfg))
3377                         die("unable to generate checkdiff for %s", one->path);
3378
3379                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3380                         struct emit_callback ecbdata;
3381                         int blank_at_eof;
3382
3383                         ecbdata.ws_rule = data.ws_rule;
3384                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3385                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3386
3387                         if (blank_at_eof) {
3388                                 static char *err;
3389                                 if (!err)
3390                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3391                                 fprintf(o->file, "%s:%d: %s.\n",
3392                                         data.filename, blank_at_eof, err);
3393                                 data.status = 1; /* report errors */
3394                         }
3395                 }
3396         }
3397  free_and_return:
3398         diff_free_filespec_data(one);
3399         diff_free_filespec_data(two);
3400         if (data.status)
3401                 o->flags.check_failed = 1;
3402 }
3403
3404 struct diff_filespec *alloc_filespec(const char *path)
3405 {
3406         struct diff_filespec *spec;
3407
3408         FLEXPTR_ALLOC_STR(spec, path, path);
3409         spec->count = 1;
3410         spec->is_binary = -1;
3411         return spec;
3412 }
3413
3414 void free_filespec(struct diff_filespec *spec)
3415 {
3416         if (!--spec->count) {
3417                 diff_free_filespec_data(spec);
3418                 free(spec);
3419         }
3420 }
3421
3422 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3423                    int oid_valid, unsigned short mode)
3424 {
3425         if (mode) {
3426                 spec->mode = canon_mode(mode);
3427                 oidcpy(&spec->oid, oid);
3428                 spec->oid_valid = oid_valid;
3429         }
3430 }
3431
3432 /*
3433  * Given a name and sha1 pair, if the index tells us the file in
3434  * the work tree has that object contents, return true, so that
3435  * prepare_temp_file() does not have to inflate and extract.
3436  */
3437 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
3438 {
3439         const struct cache_entry *ce;
3440         struct stat st;
3441         int pos, len;
3442
3443         /*
3444          * We do not read the cache ourselves here, because the
3445          * benchmark with my previous version that always reads cache
3446          * shows that it makes things worse for diff-tree comparing
3447          * two linux-2.6 kernel trees in an already checked out work
3448          * tree.  This is because most diff-tree comparisons deal with
3449          * only a small number of files, while reading the cache is
3450          * expensive for a large project, and its cost outweighs the
3451          * savings we get by not inflating the object to a temporary
3452          * file.  Practically, this code only helps when we are used
3453          * by diff-cache --cached, which does read the cache before
3454          * calling us.
3455          */
3456         if (!active_cache)
3457                 return 0;
3458
3459         /* We want to avoid the working directory if our caller
3460          * doesn't need the data in a normal file, this system
3461          * is rather slow with its stat/open/mmap/close syscalls,
3462          * and the object is contained in a pack file.  The pack
3463          * is probably already open and will be faster to obtain
3464          * the data through than the working directory.  Loose
3465          * objects however would tend to be slower as they need
3466          * to be individually opened and inflated.
3467          */
3468         if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
3469                 return 0;
3470
3471         /*
3472          * Similarly, if we'd have to convert the file contents anyway, that
3473          * makes the optimization not worthwhile.
3474          */
3475         if (!want_file && would_convert_to_git(&the_index, name))
3476                 return 0;
3477
3478         len = strlen(name);
3479         pos = cache_name_pos(name, len);
3480         if (pos < 0)
3481                 return 0;
3482         ce = active_cache[pos];
3483
3484         /*
3485          * This is not the sha1 we are looking for, or
3486          * unreusable because it is not a regular file.
3487          */
3488         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3489                 return 0;
3490
3491         /*
3492          * If ce is marked as "assume unchanged", there is no
3493          * guarantee that work tree matches what we are looking for.
3494          */
3495         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3496                 return 0;
3497
3498         /*
3499          * If ce matches the file in the work tree, we can reuse it.
3500          */
3501         if (ce_uptodate(ce) ||
3502             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
3503                 return 1;
3504
3505         return 0;
3506 }
3507
3508 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3509 {
3510         struct strbuf buf = STRBUF_INIT;
3511         char *dirty = "";
3512
3513         /* Are we looking at the work tree? */
3514         if (s->dirty_submodule)
3515                 dirty = "-dirty";
3516
3517         strbuf_addf(&buf, "Subproject commit %s%s\n",
3518                     oid_to_hex(&s->oid), dirty);
3519         s->size = buf.len;
3520         if (size_only) {
3521                 s->data = NULL;
3522                 strbuf_release(&buf);
3523         } else {
3524                 s->data = strbuf_detach(&buf, NULL);
3525                 s->should_free = 1;
3526         }
3527         return 0;
3528 }
3529
3530 /*
3531  * While doing rename detection and pickaxe operation, we may need to
3532  * grab the data for the blob (or file) for our own in-core comparison.
3533  * diff_filespec has data and size fields for this purpose.
3534  */
3535 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
3536 {
3537         int size_only = flags & CHECK_SIZE_ONLY;
3538         int err = 0;
3539         int conv_flags = global_conv_flags_eol;
3540         /*
3541          * demote FAIL to WARN to allow inspecting the situation
3542          * instead of refusing.
3543          */
3544         if (conv_flags & CONV_EOL_RNDTRP_DIE)
3545                 conv_flags = CONV_EOL_RNDTRP_WARN;
3546
3547         if (!DIFF_FILE_VALID(s))
3548                 die("internal error: asking to populate invalid file.");
3549         if (S_ISDIR(s->mode))
3550                 return -1;
3551
3552         if (s->data)
3553                 return 0;
3554
3555         if (size_only && 0 < s->size)
3556                 return 0;
3557
3558         if (S_ISGITLINK(s->mode))
3559                 return diff_populate_gitlink(s, size_only);
3560
3561         if (!s->oid_valid ||
3562             reuse_worktree_file(s->path, &s->oid, 0)) {
3563                 struct strbuf buf = STRBUF_INIT;
3564                 struct stat st;
3565                 int fd;
3566
3567                 if (lstat(s->path, &st) < 0) {
3568                 err_empty:
3569                         err = -1;
3570                 empty:
3571                         s->data = (char *)"";
3572                         s->size = 0;
3573                         return err;
3574                 }
3575                 s->size = xsize_t(st.st_size);
3576                 if (!s->size)
3577                         goto empty;
3578                 if (S_ISLNK(st.st_mode)) {
3579                         struct strbuf sb = STRBUF_INIT;
3580
3581                         if (strbuf_readlink(&sb, s->path, s->size))
3582                                 goto err_empty;
3583                         s->size = sb.len;
3584                         s->data = strbuf_detach(&sb, NULL);
3585                         s->should_free = 1;
3586                         return 0;
3587                 }
3588
3589                 /*
3590                  * Even if the caller would be happy with getting
3591                  * only the size, we cannot return early at this
3592                  * point if the path requires us to run the content
3593                  * conversion.
3594                  */
3595                 if (size_only && !would_convert_to_git(&the_index, s->path))
3596                         return 0;
3597
3598                 /*
3599                  * Note: this check uses xsize_t(st.st_size) that may
3600                  * not be the true size of the blob after it goes
3601                  * through convert_to_git().  This may not strictly be
3602                  * correct, but the whole point of big_file_threshold
3603                  * and is_binary check being that we want to avoid
3604                  * opening the file and inspecting the contents, this
3605                  * is probably fine.
3606                  */
3607                 if ((flags & CHECK_BINARY) &&
3608                     s->size > big_file_threshold && s->is_binary == -1) {
3609                         s->is_binary = 1;
3610                         return 0;
3611                 }
3612                 fd = open(s->path, O_RDONLY);
3613                 if (fd < 0)
3614                         goto err_empty;
3615                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3616                 close(fd);
3617                 s->should_munmap = 1;
3618
3619                 /*
3620                  * Convert from working tree format to canonical git format
3621                  */
3622                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, conv_flags)) {
3623                         size_t size = 0;
3624                         munmap(s->data, s->size);
3625                         s->should_munmap = 0;
3626                         s->data = strbuf_detach(&buf, &size);
3627                         s->size = size;
3628                         s->should_free = 1;
3629                 }
3630         }
3631         else {
3632                 enum object_type type;
3633                 if (size_only || (flags & CHECK_BINARY)) {
3634                         type = oid_object_info(the_repository, &s->oid,
3635                                                &s->size);
3636                         if (type < 0)
3637                                 die("unable to read %s",
3638                                     oid_to_hex(&s->oid));
3639                         if (size_only)
3640                                 return 0;
3641                         if (s->size > big_file_threshold && s->is_binary == -1) {
3642                                 s->is_binary = 1;
3643                                 return 0;
3644                         }
3645                 }
3646                 s->data = read_object_file(&s->oid, &type, &s->size);
3647                 if (!s->data)
3648                         die("unable to read %s", oid_to_hex(&s->oid));
3649                 s->should_free = 1;
3650         }
3651         return 0;
3652 }
3653
3654 void diff_free_filespec_blob(struct diff_filespec *s)
3655 {
3656         if (s->should_free)
3657                 free(s->data);
3658         else if (s->should_munmap)
3659                 munmap(s->data, s->size);
3660
3661         if (s->should_free || s->should_munmap) {
3662                 s->should_free = s->should_munmap = 0;
3663                 s->data = NULL;
3664         }
3665 }
3666
3667 void diff_free_filespec_data(struct diff_filespec *s)
3668 {
3669         diff_free_filespec_blob(s);
3670         FREE_AND_NULL(s->cnt_data);
3671 }
3672
3673 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3674                            void *blob,
3675                            unsigned long size,
3676                            const struct object_id *oid,
3677                            int mode)
3678 {
3679         struct strbuf buf = STRBUF_INIT;
3680         struct strbuf tempfile = STRBUF_INIT;
3681         char *path_dup = xstrdup(path);
3682         const char *base = basename(path_dup);
3683
3684         /* Generate "XXXXXX_basename.ext" */
3685         strbuf_addstr(&tempfile, "XXXXXX_");
3686         strbuf_addstr(&tempfile, base);
3687
3688         temp->tempfile = mks_tempfile_ts(tempfile.buf, strlen(base) + 1);
3689         if (!temp->tempfile)
3690                 die_errno("unable to create temp-file");
3691         if (convert_to_working_tree(path,
3692                         (const char *)blob, (size_t)size, &buf)) {
3693                 blob = buf.buf;
3694                 size = buf.len;
3695         }
3696         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
3697             close_tempfile_gently(temp->tempfile))
3698                 die_errno("unable to write temp-file");
3699         temp->name = get_tempfile_path(temp->tempfile);
3700         oid_to_hex_r(temp->hex, oid);
3701         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3702         strbuf_release(&buf);
3703         strbuf_release(&tempfile);
3704         free(path_dup);
3705 }
3706
3707 static struct diff_tempfile *prepare_temp_file(const char *name,
3708                 struct diff_filespec *one)
3709 {
3710         struct diff_tempfile *temp = claim_diff_tempfile();
3711
3712         if (!DIFF_FILE_VALID(one)) {
3713         not_a_valid_file:
3714                 /* A '-' entry produces this for file-2, and
3715                  * a '+' entry produces this for file-1.
3716                  */
3717                 temp->name = "/dev/null";
3718                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3719                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3720                 return temp;
3721         }
3722
3723         if (!S_ISGITLINK(one->mode) &&
3724             (!one->oid_valid ||
3725              reuse_worktree_file(name, &one->oid, 1))) {
3726                 struct stat st;
3727                 if (lstat(name, &st) < 0) {
3728                         if (errno == ENOENT)
3729                                 goto not_a_valid_file;
3730                         die_errno("stat(%s)", name);
3731                 }
3732                 if (S_ISLNK(st.st_mode)) {
3733                         struct strbuf sb = STRBUF_INIT;
3734                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3735                                 die_errno("readlink(%s)", name);
3736                         prep_temp_blob(name, temp, sb.buf, sb.len,
3737                                        (one->oid_valid ?
3738                                         &one->oid : &null_oid),
3739                                        (one->oid_valid ?
3740                                         one->mode : S_IFLNK));
3741                         strbuf_release(&sb);
3742                 }
3743                 else {
3744                         /* we can borrow from the file in the work tree */
3745                         temp->name = name;
3746                         if (!one->oid_valid)
3747                                 oid_to_hex_r(temp->hex, &null_oid);
3748                         else
3749                                 oid_to_hex_r(temp->hex, &one->oid);
3750                         /* Even though we may sometimes borrow the
3751                          * contents from the work tree, we always want
3752                          * one->mode.  mode is trustworthy even when
3753                          * !(one->oid_valid), as long as
3754                          * DIFF_FILE_VALID(one).
3755                          */
3756                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3757                 }
3758                 return temp;
3759         }
3760         else {
3761                 if (diff_populate_filespec(one, 0))
3762                         die("cannot read data blob for %s", one->path);
3763                 prep_temp_blob(name, temp, one->data, one->size,
3764                                &one->oid, one->mode);
3765         }
3766         return temp;
3767 }
3768
3769 static void add_external_diff_name(struct argv_array *argv,
3770                                    const char *name,
3771                                    struct diff_filespec *df)
3772 {
3773         struct diff_tempfile *temp = prepare_temp_file(name, df);
3774         argv_array_push(argv, temp->name);
3775         argv_array_push(argv, temp->hex);
3776         argv_array_push(argv, temp->mode);
3777 }
3778
3779 /* An external diff command takes:
3780  *
3781  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3782  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3783  *
3784  */
3785 static void run_external_diff(const char *pgm,
3786                               const char *name,
3787                               const char *other,
3788                               struct diff_filespec *one,
3789                               struct diff_filespec *two,
3790                               const char *xfrm_msg,
3791                               int complete_rewrite,
3792                               struct diff_options *o)
3793 {
3794         struct argv_array argv = ARGV_ARRAY_INIT;
3795         struct argv_array env = ARGV_ARRAY_INIT;
3796         struct diff_queue_struct *q = &diff_queued_diff;
3797
3798         argv_array_push(&argv, pgm);
3799         argv_array_push(&argv, name);
3800
3801         if (one && two) {
3802                 add_external_diff_name(&argv, name, one);
3803                 if (!other)
3804                         add_external_diff_name(&argv, name, two);
3805                 else {
3806                         add_external_diff_name(&argv, other, two);
3807                         argv_array_push(&argv, other);
3808                         argv_array_push(&argv, xfrm_msg);
3809                 }
3810         }
3811
3812         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3813         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3814
3815         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3816                 die(_("external diff died, stopping at %s"), name);
3817
3818         remove_tempfile();
3819         argv_array_clear(&argv);
3820         argv_array_clear(&env);
3821 }
3822
3823 static int similarity_index(struct diff_filepair *p)
3824 {
3825         return p->score * 100 / MAX_SCORE;
3826 }
3827
3828 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3829 {
3830         if (startup_info->have_repository)
3831                 return find_unique_abbrev(oid, abbrev);
3832         else {
3833                 char *hex = oid_to_hex(oid);
3834                 if (abbrev < 0)
3835                         abbrev = FALLBACK_DEFAULT_ABBREV;
3836                 if (abbrev > GIT_SHA1_HEXSZ)
3837                         BUG("oid abbreviation out of range: %d", abbrev);
3838                 if (abbrev)
3839                         hex[abbrev] = '\0';
3840                 return hex;
3841         }
3842 }
3843
3844 static void fill_metainfo(struct strbuf *msg,
3845                           const char *name,
3846                           const char *other,
3847                           struct diff_filespec *one,
3848                           struct diff_filespec *two,
3849                           struct diff_options *o,
3850                           struct diff_filepair *p,
3851                           int *must_show_header,
3852                           int use_color)
3853 {
3854         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3855         const char *reset = diff_get_color(use_color, DIFF_RESET);
3856         const char *line_prefix = diff_line_prefix(o);
3857
3858         *must_show_header = 1;
3859         strbuf_init(msg, PATH_MAX * 2 + 300);
3860         switch (p->status) {
3861         case DIFF_STATUS_COPIED:
3862                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3863                             line_prefix, set, similarity_index(p));
3864                 strbuf_addf(msg, "%s\n%s%scopy from ",
3865                             reset,  line_prefix, set);
3866                 quote_c_style(name, msg, NULL, 0);
3867                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3868                 quote_c_style(other, msg, NULL, 0);
3869                 strbuf_addf(msg, "%s\n", reset);
3870                 break;
3871         case DIFF_STATUS_RENAMED:
3872                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3873                             line_prefix, set, similarity_index(p));
3874                 strbuf_addf(msg, "%s\n%s%srename from ",
3875                             reset, line_prefix, set);
3876                 quote_c_style(name, msg, NULL, 0);
3877                 strbuf_addf(msg, "%s\n%s%srename to ",
3878                             reset, line_prefix, set);
3879                 quote_c_style(other, msg, NULL, 0);
3880                 strbuf_addf(msg, "%s\n", reset);
3881                 break;
3882         case DIFF_STATUS_MODIFIED:
3883                 if (p->score) {
3884                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3885                                     line_prefix,
3886                                     set, similarity_index(p), reset);
3887                         break;
3888                 }
3889                 /* fallthru */
3890         default:
3891                 *must_show_header = 0;
3892         }
3893         if (one && two && oidcmp(&one->oid, &two->oid)) {
3894                 const unsigned hexsz = the_hash_algo->hexsz;
3895                 int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
3896
3897                 if (o->flags.binary) {
3898                         mmfile_t mf;
3899                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3900                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3901                                 abbrev = hexsz;
3902                 }
3903                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3904                             diff_abbrev_oid(&one->oid, abbrev),
3905                             diff_abbrev_oid(&two->oid, abbrev));
3906                 if (one->mode == two->mode)
3907                         strbuf_addf(msg, " %06o", one->mode);
3908                 strbuf_addf(msg, "%s\n", reset);
3909         }
3910 }
3911
3912 static void run_diff_cmd(const char *pgm,
3913                          const char *name,
3914                          const char *other,
3915                          const char *attr_path,
3916                          struct diff_filespec *one,
3917                          struct diff_filespec *two,
3918                          struct strbuf *msg,
3919                          struct diff_options *o,
3920                          struct diff_filepair *p)
3921 {
3922         const char *xfrm_msg = NULL;
3923         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3924         int must_show_header = 0;
3925
3926
3927         if (o->flags.allow_external) {
3928                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3929                 if (drv && drv->external)
3930                         pgm = drv->external;
3931         }
3932
3933         if (msg) {
3934                 /*
3935                  * don't use colors when the header is intended for an
3936                  * external diff driver
3937                  */
3938                 fill_metainfo(msg, name, other, one, two, o, p,
3939                               &must_show_header,
3940                               want_color(o->use_color) && !pgm);
3941                 xfrm_msg = msg->len ? msg->buf : NULL;
3942         }
3943
3944         if (pgm) {
3945                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3946                                   complete_rewrite, o);
3947                 return;
3948         }
3949         if (one && two)
3950                 builtin_diff(name, other ? other : name,
3951                              one, two, xfrm_msg, must_show_header,
3952                              o, complete_rewrite);
3953         else
3954                 fprintf(o->file, "* Unmerged path %s\n", name);
3955 }
3956
3957 static void diff_fill_oid_info(struct diff_filespec *one)
3958 {
3959         if (DIFF_FILE_VALID(one)) {
3960                 if (!one->oid_valid) {
3961                         struct stat st;
3962                         if (one->is_stdin) {
3963                                 oidclr(&one->oid);
3964                                 return;
3965                         }
3966                         if (lstat(one->path, &st) < 0)
3967                                 die_errno("stat '%s'", one->path);
3968                         if (index_path(&one->oid, one->path, &st, 0))
3969                                 die("cannot hash %s", one->path);
3970                 }
3971         }
3972         else
3973                 oidclr(&one->oid);
3974 }
3975
3976 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3977 {
3978         /* Strip the prefix but do not molest /dev/null and absolute paths */
3979         if (*namep && **namep != '/') {
3980                 *namep += prefix_length;
3981                 if (**namep == '/')
3982                         ++*namep;
3983         }
3984         if (*otherp && **otherp != '/') {
3985                 *otherp += prefix_length;
3986                 if (**otherp == '/')
3987                         ++*otherp;
3988         }
3989 }
3990
3991 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3992 {
3993         const char *pgm = external_diff();
3994         struct strbuf msg;
3995         struct diff_filespec *one = p->one;
3996         struct diff_filespec *two = p->two;
3997         const char *name;
3998         const char *other;
3999         const char *attr_path;
4000
4001         name  = one->path;
4002         other = (strcmp(name, two->path) ? two->path : NULL);
4003         attr_path = name;
4004         if (o->prefix_length)
4005                 strip_prefix(o->prefix_length, &name, &other);
4006
4007         if (!o->flags.allow_external)
4008                 pgm = NULL;
4009
4010         if (DIFF_PAIR_UNMERGED(p)) {
4011                 run_diff_cmd(pgm, name, NULL, attr_path,
4012                              NULL, NULL, NULL, o, p);
4013                 return;
4014         }
4015
4016         diff_fill_oid_info(one);
4017         diff_fill_oid_info(two);
4018
4019         if (!pgm &&
4020             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4021             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4022                 /*
4023                  * a filepair that changes between file and symlink
4024                  * needs to be split into deletion and creation.
4025                  */
4026                 struct diff_filespec *null = alloc_filespec(two->path);
4027                 run_diff_cmd(NULL, name, other, attr_path,
4028                              one, null, &msg, o, p);
4029                 free(null);
4030                 strbuf_release(&msg);
4031
4032                 null = alloc_filespec(one->path);
4033                 run_diff_cmd(NULL, name, other, attr_path,
4034                              null, two, &msg, o, p);
4035                 free(null);
4036         }
4037         else
4038                 run_diff_cmd(pgm, name, other, attr_path,
4039                              one, two, &msg, o, p);
4040
4041         strbuf_release(&msg);
4042 }
4043
4044 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4045                          struct diffstat_t *diffstat)
4046 {
4047         const char *name;
4048         const char *other;
4049
4050         if (DIFF_PAIR_UNMERGED(p)) {
4051                 /* unmerged */
4052                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
4053                 return;
4054         }
4055
4056         name = p->one->path;
4057         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4058
4059         if (o->prefix_length)
4060                 strip_prefix(o->prefix_length, &name, &other);
4061
4062         diff_fill_oid_info(p->one);
4063         diff_fill_oid_info(p->two);
4064
4065         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
4066 }
4067
4068 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4069 {
4070         const char *name;
4071         const char *other;
4072         const char *attr_path;
4073
4074         if (DIFF_PAIR_UNMERGED(p)) {
4075                 /* unmerged */
4076                 return;
4077         }
4078
4079         name = p->one->path;
4080         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4081         attr_path = other ? other : name;
4082
4083         if (o->prefix_length)
4084                 strip_prefix(o->prefix_length, &name, &other);
4085
4086         diff_fill_oid_info(p->one);
4087         diff_fill_oid_info(p->two);
4088
4089         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4090 }
4091
4092 void diff_setup(struct diff_options *options)
4093 {
4094         memcpy(options, &default_diff_options, sizeof(*options));
4095
4096         options->file = stdout;
4097
4098         options->abbrev = DEFAULT_ABBREV;
4099         options->line_termination = '\n';
4100         options->break_opt = -1;
4101         options->rename_limit = -1;
4102         options->dirstat_permille = diff_dirstat_permille_default;
4103         options->context = diff_context_default;
4104         options->interhunkcontext = diff_interhunk_context_default;
4105         options->ws_error_highlight = ws_error_highlight_default;
4106         options->flags.rename_empty = 1;
4107         options->objfind = NULL;
4108
4109         /* pathchange left =NULL by default */
4110         options->change = diff_change;
4111         options->add_remove = diff_addremove;
4112         options->use_color = diff_use_color_default;
4113         options->detect_rename = diff_detect_rename_default;
4114         options->xdl_opts |= diff_algorithm;
4115         if (diff_indent_heuristic)
4116                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4117
4118         options->orderfile = diff_order_file_cfg;
4119
4120         if (diff_no_prefix) {
4121                 options->a_prefix = options->b_prefix = "";
4122         } else if (!diff_mnemonic_prefix) {
4123                 options->a_prefix = "a/";
4124                 options->b_prefix = "b/";
4125         }
4126
4127         options->color_moved = diff_color_moved_default;
4128 }
4129
4130 void diff_setup_done(struct diff_options *options)
4131 {
4132         unsigned check_mask = DIFF_FORMAT_NAME |
4133                               DIFF_FORMAT_NAME_STATUS |
4134                               DIFF_FORMAT_CHECKDIFF |
4135                               DIFF_FORMAT_NO_OUTPUT;
4136         /*
4137          * This must be signed because we're comparing against a potentially
4138          * negative value.
4139          */
4140         const int hexsz = the_hash_algo->hexsz;
4141
4142         if (options->set_default)
4143                 options->set_default(options);
4144
4145         if (HAS_MULTI_BITS(options->output_format & check_mask))
4146                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4147
4148         if (HAS_MULTI_BITS(options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
4149                 die(_("-G, -S and --find-object are mutually exclusive"));
4150
4151         /*
4152          * Most of the time we can say "there are changes"
4153          * only by checking if there are changed paths, but
4154          * --ignore-whitespace* options force us to look
4155          * inside contents.
4156          */
4157
4158         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4159                 options->flags.diff_from_contents = 1;
4160         else
4161                 options->flags.diff_from_contents = 0;
4162
4163         if (options->flags.find_copies_harder)
4164                 options->detect_rename = DIFF_DETECT_COPY;
4165
4166         if (!options->flags.relative_name)
4167                 options->prefix = NULL;
4168         if (options->prefix)
4169                 options->prefix_length = strlen(options->prefix);
4170         else
4171                 options->prefix_length = 0;
4172
4173         if (options->output_format & (DIFF_FORMAT_NAME |
4174                                       DIFF_FORMAT_NAME_STATUS |
4175                                       DIFF_FORMAT_CHECKDIFF |
4176                                       DIFF_FORMAT_NO_OUTPUT))
4177                 options->output_format &= ~(DIFF_FORMAT_RAW |
4178                                             DIFF_FORMAT_NUMSTAT |
4179                                             DIFF_FORMAT_DIFFSTAT |
4180                                             DIFF_FORMAT_SHORTSTAT |
4181                                             DIFF_FORMAT_DIRSTAT |
4182                                             DIFF_FORMAT_SUMMARY |
4183                                             DIFF_FORMAT_PATCH);
4184
4185         /*
4186          * These cases always need recursive; we do not drop caller-supplied
4187          * recursive bits for other formats here.
4188          */
4189         if (options->output_format & (DIFF_FORMAT_PATCH |
4190                                       DIFF_FORMAT_NUMSTAT |
4191                                       DIFF_FORMAT_DIFFSTAT |
4192                                       DIFF_FORMAT_SHORTSTAT |
4193                                       DIFF_FORMAT_DIRSTAT |
4194                                       DIFF_FORMAT_SUMMARY |
4195                                       DIFF_FORMAT_CHECKDIFF))
4196                 options->flags.recursive = 1;
4197         /*
4198          * Also pickaxe would not work very well if you do not say recursive
4199          */
4200         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
4201                 options->flags.recursive = 1;
4202         /*
4203          * When patches are generated, submodules diffed against the work tree
4204          * must be checked for dirtiness too so it can be shown in the output
4205          */
4206         if (options->output_format & DIFF_FORMAT_PATCH)
4207                 options->flags.dirty_submodules = 1;
4208
4209         if (options->detect_rename && options->rename_limit < 0)
4210                 options->rename_limit = diff_rename_limit_default;
4211         if (options->setup & DIFF_SETUP_USE_CACHE) {
4212                 if (!active_cache)
4213                         /* read-cache does not die even when it fails
4214                          * so it is safe for us to do this here.  Also
4215                          * it does not smudge active_cache or active_nr
4216                          * when it fails, so we do not have to worry about
4217                          * cleaning it up ourselves either.
4218                          */
4219                         read_cache();
4220         }
4221         if (hexsz < options->abbrev)
4222                 options->abbrev = hexsz; /* full */
4223
4224         /*
4225          * It does not make sense to show the first hit we happened
4226          * to have found.  It does not make sense not to return with
4227          * exit code in such a case either.
4228          */
4229         if (options->flags.quick) {
4230                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4231                 options->flags.exit_with_status = 1;
4232         }
4233
4234         options->diff_path_counter = 0;
4235
4236         if (options->flags.follow_renames && options->pathspec.nr != 1)
4237                 die(_("--follow requires exactly one pathspec"));
4238
4239         if (!options->use_color || external_diff())
4240                 options->color_moved = 0;
4241 }
4242
4243 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4244 {
4245         char c, *eq;
4246         int len;
4247
4248         if (*arg != '-')
4249                 return 0;
4250         c = *++arg;
4251         if (!c)
4252                 return 0;
4253         if (c == arg_short) {
4254                 c = *++arg;
4255                 if (!c)
4256                         return 1;
4257                 if (val && isdigit(c)) {
4258                         char *end;
4259                         int n = strtoul(arg, &end, 10);
4260                         if (*end)
4261                                 return 0;
4262                         *val = n;
4263                         return 1;
4264                 }
4265                 return 0;
4266         }
4267         if (c != '-')
4268                 return 0;
4269         arg++;
4270         eq = strchrnul(arg, '=');
4271         len = eq - arg;
4272         if (!len || strncmp(arg, arg_long, len))
4273                 return 0;
4274         if (*eq) {
4275                 int n;
4276                 char *end;
4277                 if (!isdigit(*++eq))
4278                         return 0;
4279                 n = strtoul(eq, &end, 10);
4280                 if (*end)
4281                         return 0;
4282                 *val = n;
4283         }
4284         return 1;
4285 }
4286
4287 static int diff_scoreopt_parse(const char *opt);
4288
4289 static inline int short_opt(char opt, const char **argv,
4290                             const char **optarg)
4291 {
4292         const char *arg = argv[0];
4293         if (arg[0] != '-' || arg[1] != opt)
4294                 return 0;
4295         if (arg[2] != '\0') {
4296                 *optarg = arg + 2;
4297                 return 1;
4298         }
4299         if (!argv[1])
4300                 die("Option '%c' requires a value", opt);
4301         *optarg = argv[1];
4302         return 2;
4303 }
4304
4305 int parse_long_opt(const char *opt, const char **argv,
4306                    const char **optarg)
4307 {
4308         const char *arg = argv[0];
4309         if (!skip_prefix(arg, "--", &arg))
4310                 return 0;
4311         if (!skip_prefix(arg, opt, &arg))
4312                 return 0;
4313         if (*arg == '=') { /* stuck form: --option=value */
4314                 *optarg = arg + 1;
4315                 return 1;
4316         }
4317         if (*arg != '\0')
4318                 return 0;
4319         /* separate form: --option value */
4320         if (!argv[1])
4321                 die("Option '--%s' requires a value", opt);
4322         *optarg = argv[1];
4323         return 2;
4324 }
4325
4326 static int stat_opt(struct diff_options *options, const char **av)
4327 {
4328         const char *arg = av[0];
4329         char *end;
4330         int width = options->stat_width;
4331         int name_width = options->stat_name_width;
4332         int graph_width = options->stat_graph_width;
4333         int count = options->stat_count;
4334         int argcount = 1;
4335
4336         if (!skip_prefix(arg, "--stat", &arg))
4337                 BUG("stat option does not begin with --stat: %s", arg);
4338         end = (char *)arg;
4339
4340         switch (*arg) {
4341         case '-':
4342                 if (skip_prefix(arg, "-width", &arg)) {
4343                         if (*arg == '=')
4344                                 width = strtoul(arg + 1, &end, 10);
4345                         else if (!*arg && !av[1])
4346                                 die_want_option("--stat-width");
4347                         else if (!*arg) {
4348                                 width = strtoul(av[1], &end, 10);
4349                                 argcount = 2;
4350                         }
4351                 } else if (skip_prefix(arg, "-name-width", &arg)) {
4352                         if (*arg == '=')
4353                                 name_width = strtoul(arg + 1, &end, 10);
4354                         else if (!*arg && !av[1])
4355                                 die_want_option("--stat-name-width");
4356                         else if (!*arg) {
4357                                 name_width = strtoul(av[1], &end, 10);
4358                                 argcount = 2;
4359                         }
4360                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
4361                         if (*arg == '=')
4362                                 graph_width = strtoul(arg + 1, &end, 10);
4363                         else if (!*arg && !av[1])
4364                                 die_want_option("--stat-graph-width");
4365                         else if (!*arg) {
4366                                 graph_width = strtoul(av[1], &end, 10);
4367                                 argcount = 2;
4368                         }
4369                 } else if (skip_prefix(arg, "-count", &arg)) {
4370                         if (*arg == '=')
4371                                 count = strtoul(arg + 1, &end, 10);
4372                         else if (!*arg && !av[1])
4373                                 die_want_option("--stat-count");
4374                         else if (!*arg) {
4375                                 count = strtoul(av[1], &end, 10);
4376                                 argcount = 2;
4377                         }
4378                 }
4379                 break;
4380         case '=':
4381                 width = strtoul(arg+1, &end, 10);
4382                 if (*end == ',')
4383                         name_width = strtoul(end+1, &end, 10);
4384                 if (*end == ',')
4385                         count = strtoul(end+1, &end, 10);
4386         }
4387
4388         /* Important! This checks all the error cases! */
4389         if (*end)
4390                 return 0;
4391         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4392         options->stat_name_width = name_width;
4393         options->stat_graph_width = graph_width;
4394         options->stat_width = width;
4395         options->stat_count = count;
4396         return argcount;
4397 }
4398
4399 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4400 {
4401         struct strbuf errmsg = STRBUF_INIT;
4402         if (parse_dirstat_params(options, params, &errmsg))
4403                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4404                     errmsg.buf);
4405         strbuf_release(&errmsg);
4406         /*
4407          * The caller knows a dirstat-related option is given from the command
4408          * line; allow it to say "return this_function();"
4409          */
4410         options->output_format |= DIFF_FORMAT_DIRSTAT;
4411         return 1;
4412 }
4413
4414 static int parse_submodule_opt(struct diff_options *options, const char *value)
4415 {
4416         if (parse_submodule_params(options, value))
4417                 die(_("Failed to parse --submodule option parameter: '%s'"),
4418                         value);
4419         return 1;
4420 }
4421
4422 static const char diff_status_letters[] = {
4423         DIFF_STATUS_ADDED,
4424         DIFF_STATUS_COPIED,
4425         DIFF_STATUS_DELETED,
4426         DIFF_STATUS_MODIFIED,
4427         DIFF_STATUS_RENAMED,
4428         DIFF_STATUS_TYPE_CHANGED,
4429         DIFF_STATUS_UNKNOWN,
4430         DIFF_STATUS_UNMERGED,
4431         DIFF_STATUS_FILTER_AON,
4432         DIFF_STATUS_FILTER_BROKEN,
4433         '\0',
4434 };
4435
4436 static unsigned int filter_bit['Z' + 1];
4437
4438 static void prepare_filter_bits(void)
4439 {
4440         int i;
4441
4442         if (!filter_bit[DIFF_STATUS_ADDED]) {
4443                 for (i = 0; diff_status_letters[i]; i++)
4444                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4445         }
4446 }
4447
4448 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4449 {
4450         return opt->filter & filter_bit[(int) status];
4451 }
4452
4453 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4454 {
4455         int i, optch;
4456
4457         prepare_filter_bits();
4458
4459         /*
4460          * If there is a negation e.g. 'd' in the input, and we haven't
4461          * initialized the filter field with another --diff-filter, start
4462          * from full set of bits, except for AON.
4463          */
4464         if (!opt->filter) {
4465                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4466                         if (optch < 'a' || 'z' < optch)
4467                                 continue;
4468                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4469                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4470                         break;
4471                 }
4472         }
4473
4474         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4475                 unsigned int bit;
4476                 int negate;
4477
4478                 if ('a' <= optch && optch <= 'z') {
4479                         negate = 1;
4480                         optch = toupper(optch);
4481                 } else {
4482                         negate = 0;
4483                 }
4484
4485                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4486                 if (!bit)
4487                         return optarg[i];
4488                 if (negate)
4489                         opt->filter &= ~bit;
4490                 else
4491                         opt->filter |= bit;
4492         }
4493         return 0;
4494 }
4495
4496 static void enable_patch_output(int *fmt) {
4497         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4498         *fmt |= DIFF_FORMAT_PATCH;
4499 }
4500
4501 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4502 {
4503         int val = parse_ws_error_highlight(arg);
4504
4505         if (val < 0) {
4506                 error("unknown value after ws-error-highlight=%.*s",
4507                       -1 - val, arg);
4508                 return 0;
4509         }
4510         opt->ws_error_highlight = val;
4511         return 1;
4512 }
4513
4514 static int parse_objfind_opt(struct diff_options *opt, const char *arg)
4515 {
4516         struct object_id oid;
4517
4518         if (get_oid(arg, &oid))
4519                 return error("unable to resolve '%s'", arg);
4520
4521         if (!opt->objfind)
4522                 opt->objfind = xcalloc(1, sizeof(*opt->objfind));
4523
4524         opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND;
4525         opt->flags.recursive = 1;
4526         opt->flags.tree_in_recursive = 1;
4527         oidset_insert(opt->objfind, &oid);
4528         return 1;
4529 }
4530
4531 int diff_opt_parse(struct diff_options *options,
4532                    const char **av, int ac, const char *prefix)
4533 {
4534         const char *arg = av[0];
4535         const char *optarg;
4536         int argcount;
4537
4538         if (!prefix)
4539                 prefix = "";
4540
4541         /* Output format options */
4542         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4543             || opt_arg(arg, 'U', "unified", &options->context))
4544                 enable_patch_output(&options->output_format);
4545         else if (!strcmp(arg, "--raw"))
4546                 options->output_format |= DIFF_FORMAT_RAW;
4547         else if (!strcmp(arg, "--patch-with-raw")) {
4548                 enable_patch_output(&options->output_format);
4549                 options->output_format |= DIFF_FORMAT_RAW;
4550         } else if (!strcmp(arg, "--numstat"))
4551                 options->output_format |= DIFF_FORMAT_NUMSTAT;
4552         else if (!strcmp(arg, "--shortstat"))
4553                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
4554         else if (skip_prefix(arg, "-X", &arg) ||
4555                  skip_to_optional_arg(arg, "--dirstat", &arg))
4556                 return parse_dirstat_opt(options, arg);
4557         else if (!strcmp(arg, "--cumulative"))
4558                 return parse_dirstat_opt(options, "cumulative");
4559         else if (skip_to_optional_arg(arg, "--dirstat-by-file", &arg)) {
4560                 parse_dirstat_opt(options, "files");
4561                 return parse_dirstat_opt(options, arg);
4562         }
4563         else if (!strcmp(arg, "--check"))
4564                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
4565         else if (!strcmp(arg, "--summary"))
4566                 options->output_format |= DIFF_FORMAT_SUMMARY;
4567         else if (!strcmp(arg, "--patch-with-stat")) {
4568                 enable_patch_output(&options->output_format);
4569                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
4570         } else if (!strcmp(arg, "--name-only"))
4571                 options->output_format |= DIFF_FORMAT_NAME;
4572         else if (!strcmp(arg, "--name-status"))
4573                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
4574         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4575                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4576         else if (starts_with(arg, "--stat"))
4577                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
4578                 return stat_opt(options, av);
4579         else if (!strcmp(arg, "--compact-summary")) {
4580                  options->flags.stat_with_summary = 1;
4581                  options->output_format |= DIFF_FORMAT_DIFFSTAT;
4582         } else if (!strcmp(arg, "--no-compact-summary"))
4583                  options->flags.stat_with_summary = 0;
4584
4585         /* renames options */
4586         else if (starts_with(arg, "-B") ||
4587                  skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
4588                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4589                         return error("invalid argument to -B: %s", arg+2);
4590         }
4591         else if (starts_with(arg, "-M") ||
4592                  skip_to_optional_arg(arg, "--find-renames", NULL)) {
4593                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4594                         return error("invalid argument to -M: %s", arg+2);
4595                 options->detect_rename = DIFF_DETECT_RENAME;
4596         }
4597         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4598                 options->irreversible_delete = 1;
4599         }
4600         else if (starts_with(arg, "-C") ||
4601                  skip_to_optional_arg(arg, "--find-copies", NULL)) {
4602                 if (options->detect_rename == DIFF_DETECT_COPY)
4603                         options->flags.find_copies_harder = 1;
4604                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4605                         return error("invalid argument to -C: %s", arg+2);
4606                 options->detect_rename = DIFF_DETECT_COPY;
4607         }
4608         else if (!strcmp(arg, "--no-renames"))
4609                 options->detect_rename = 0;
4610         else if (!strcmp(arg, "--rename-empty"))
4611                 options->flags.rename_empty = 1;
4612         else if (!strcmp(arg, "--no-rename-empty"))
4613                 options->flags.rename_empty = 0;
4614         else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
4615                 options->flags.relative_name = 1;
4616                 if (arg)
4617                         options->prefix = arg;
4618         }
4619
4620         /* xdiff options */
4621         else if (!strcmp(arg, "--minimal"))
4622                 DIFF_XDL_SET(options, NEED_MINIMAL);
4623         else if (!strcmp(arg, "--no-minimal"))
4624                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4625         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4626                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4627         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4628                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4629         else if (!strcmp(arg, "--ignore-space-at-eol"))
4630                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4631         else if (!strcmp(arg, "--ignore-cr-at-eol"))
4632                 DIFF_XDL_SET(options, IGNORE_CR_AT_EOL);
4633         else if (!strcmp(arg, "--ignore-blank-lines"))
4634                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4635         else if (!strcmp(arg, "--indent-heuristic"))
4636                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4637         else if (!strcmp(arg, "--no-indent-heuristic"))
4638                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4639         else if (!strcmp(arg, "--patience")) {
4640                 int i;
4641                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4642                 /*
4643                  * Both --patience and --anchored use PATIENCE_DIFF
4644                  * internally, so remove any anchors previously
4645                  * specified.
4646                  */
4647                 for (i = 0; i < options->anchors_nr; i++)
4648                         free(options->anchors[i]);
4649                 options->anchors_nr = 0;
4650         } else if (!strcmp(arg, "--histogram"))
4651                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4652         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4653                 long value = parse_algorithm_value(optarg);
4654                 if (value < 0)
4655                         return error("option diff-algorithm accepts \"myers\", "
4656                                      "\"minimal\", \"patience\" and \"histogram\"");
4657                 /* clear out previous settings */
4658                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4659                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4660                 options->xdl_opts |= value;
4661                 return argcount;
4662         } else if (skip_prefix(arg, "--anchored=", &arg)) {
4663                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4664                 ALLOC_GROW(options->anchors, options->anchors_nr + 1,
4665                            options->anchors_alloc);
4666                 options->anchors[options->anchors_nr++] = xstrdup(arg);
4667         }
4668
4669         /* flags options */
4670         else if (!strcmp(arg, "--binary")) {
4671                 enable_patch_output(&options->output_format);
4672                 options->flags.binary = 1;
4673         }
4674         else if (!strcmp(arg, "--full-index"))
4675                 options->flags.full_index = 1;
4676         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4677                 options->flags.text = 1;
4678         else if (!strcmp(arg, "-R"))
4679                 options->flags.reverse_diff = 1;
4680         else if (!strcmp(arg, "--find-copies-harder"))
4681                 options->flags.find_copies_harder = 1;
4682         else if (!strcmp(arg, "--follow"))
4683                 options->flags.follow_renames = 1;
4684         else if (!strcmp(arg, "--no-follow")) {
4685                 options->flags.follow_renames = 0;
4686                 options->flags.default_follow_renames = 0;
4687         } else if (skip_to_optional_arg_default(arg, "--color", &arg, "always")) {
4688                 int value = git_config_colorbool(NULL, arg);
4689                 if (value < 0)
4690                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
4691                 options->use_color = value;
4692         }
4693         else if (!strcmp(arg, "--no-color"))
4694                 options->use_color = 0;
4695         else if (!strcmp(arg, "--color-moved")) {
4696                 if (diff_color_moved_default)
4697                         options->color_moved = diff_color_moved_default;
4698                 if (options->color_moved == COLOR_MOVED_NO)
4699                         options->color_moved = COLOR_MOVED_DEFAULT;
4700         } else if (!strcmp(arg, "--no-color-moved"))
4701                 options->color_moved = COLOR_MOVED_NO;
4702         else if (skip_prefix(arg, "--color-moved=", &arg)) {
4703                 int cm = parse_color_moved(arg);
4704                 if (cm < 0)
4705                         die("bad --color-moved argument: %s", arg);
4706                 options->color_moved = cm;
4707         } else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
4708                 options->use_color = 1;
4709                 options->word_diff = DIFF_WORDS_COLOR;
4710         }
4711         else if (!strcmp(arg, "--word-diff")) {
4712                 if (options->word_diff == DIFF_WORDS_NONE)
4713                         options->word_diff = DIFF_WORDS_PLAIN;
4714         }
4715         else if (skip_prefix(arg, "--word-diff=", &arg)) {
4716                 if (!strcmp(arg, "plain"))
4717                         options->word_diff = DIFF_WORDS_PLAIN;
4718                 else if (!strcmp(arg, "color")) {
4719                         options->use_color = 1;
4720                         options->word_diff = DIFF_WORDS_COLOR;
4721                 }
4722                 else if (!strcmp(arg, "porcelain"))
4723                         options->word_diff = DIFF_WORDS_PORCELAIN;
4724                 else if (!strcmp(arg, "none"))
4725                         options->word_diff = DIFF_WORDS_NONE;
4726                 else
4727                         die("bad --word-diff argument: %s", arg);
4728         }
4729         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4730                 if (options->word_diff == DIFF_WORDS_NONE)
4731                         options->word_diff = DIFF_WORDS_PLAIN;
4732                 options->word_regex = optarg;
4733                 return argcount;
4734         }
4735         else if (!strcmp(arg, "--exit-code"))
4736                 options->flags.exit_with_status = 1;
4737         else if (!strcmp(arg, "--quiet"))
4738                 options->flags.quick = 1;
4739         else if (!strcmp(arg, "--ext-diff"))
4740                 options->flags.allow_external = 1;
4741         else if (!strcmp(arg, "--no-ext-diff"))
4742                 options->flags.allow_external = 0;
4743         else if (!strcmp(arg, "--textconv")) {
4744                 options->flags.allow_textconv = 1;
4745                 options->flags.textconv_set_via_cmdline = 1;
4746         } else if (!strcmp(arg, "--no-textconv"))
4747                 options->flags.allow_textconv = 0;
4748         else if (skip_to_optional_arg_default(arg, "--ignore-submodules", &arg, "all")) {
4749                 options->flags.override_submodule_config = 1;
4750                 handle_ignore_submodules_arg(options, arg);
4751         } else if (skip_to_optional_arg_default(arg, "--submodule", &arg, "log"))
4752                 return parse_submodule_opt(options, arg);
4753         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4754                 return parse_ws_error_highlight_opt(options, arg);
4755         else if (!strcmp(arg, "--ita-invisible-in-index"))
4756                 options->ita_invisible_in_index = 1;
4757         else if (!strcmp(arg, "--ita-visible-in-index"))
4758                 options->ita_invisible_in_index = 0;
4759
4760         /* misc options */
4761         else if (!strcmp(arg, "-z"))
4762                 options->line_termination = 0;
4763         else if ((argcount = short_opt('l', av, &optarg))) {
4764                 options->rename_limit = strtoul(optarg, NULL, 10);
4765                 return argcount;
4766         }
4767         else if ((argcount = short_opt('S', av, &optarg))) {
4768                 options->pickaxe = optarg;
4769                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4770                 return argcount;
4771         } else if ((argcount = short_opt('G', av, &optarg))) {
4772                 options->pickaxe = optarg;
4773                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4774                 return argcount;
4775         }
4776         else if (!strcmp(arg, "--pickaxe-all"))
4777                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4778         else if (!strcmp(arg, "--pickaxe-regex"))
4779                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4780         else if ((argcount = short_opt('O', av, &optarg))) {
4781                 options->orderfile = prefix_filename(prefix, optarg);
4782                 return argcount;
4783         } else if (skip_prefix(arg, "--find-object=", &arg))
4784                 return parse_objfind_opt(options, arg);
4785         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4786                 int offending = parse_diff_filter_opt(optarg, options);
4787                 if (offending)
4788                         die("unknown change class '%c' in --diff-filter=%s",
4789                             offending, optarg);
4790                 return argcount;
4791         }
4792         else if (!strcmp(arg, "--no-abbrev"))
4793                 options->abbrev = 0;
4794         else if (!strcmp(arg, "--abbrev"))
4795                 options->abbrev = DEFAULT_ABBREV;
4796         else if (skip_prefix(arg, "--abbrev=", &arg)) {
4797                 options->abbrev = strtoul(arg, NULL, 10);
4798                 if (options->abbrev < MINIMUM_ABBREV)
4799                         options->abbrev = MINIMUM_ABBREV;
4800                 else if (the_hash_algo->hexsz < options->abbrev)
4801                         options->abbrev = the_hash_algo->hexsz;
4802         }
4803         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4804                 options->a_prefix = optarg;
4805                 return argcount;
4806         }
4807         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4808                 options->line_prefix = optarg;
4809                 options->line_prefix_length = strlen(options->line_prefix);
4810                 graph_setup_line_prefix(options);
4811                 return argcount;
4812         }
4813         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4814                 options->b_prefix = optarg;
4815                 return argcount;
4816         }
4817         else if (!strcmp(arg, "--no-prefix"))
4818                 options->a_prefix = options->b_prefix = "";
4819         else if (opt_arg(arg, '\0', "inter-hunk-context",
4820                          &options->interhunkcontext))
4821                 ;
4822         else if (!strcmp(arg, "-W"))
4823                 options->flags.funccontext = 1;
4824         else if (!strcmp(arg, "--function-context"))
4825                 options->flags.funccontext = 1;
4826         else if (!strcmp(arg, "--no-function-context"))
4827                 options->flags.funccontext = 0;
4828         else if ((argcount = parse_long_opt("output", av, &optarg))) {
4829                 char *path = prefix_filename(prefix, optarg);
4830                 options->file = xfopen(path, "w");
4831                 options->close_file = 1;
4832                 if (options->use_color != GIT_COLOR_ALWAYS)
4833                         options->use_color = GIT_COLOR_NEVER;
4834                 free(path);
4835                 return argcount;
4836         } else
4837                 return 0;
4838         return 1;
4839 }
4840
4841 int parse_rename_score(const char **cp_p)
4842 {
4843         unsigned long num, scale;
4844         int ch, dot;
4845         const char *cp = *cp_p;
4846
4847         num = 0;
4848         scale = 1;
4849         dot = 0;
4850         for (;;) {
4851                 ch = *cp;
4852                 if ( !dot && ch == '.' ) {
4853                         scale = 1;
4854                         dot = 1;
4855                 } else if ( ch == '%' ) {
4856                         scale = dot ? scale*100 : 100;
4857                         cp++;   /* % is always at the end */
4858                         break;
4859                 } else if ( ch >= '0' && ch <= '9' ) {
4860                         if ( scale < 100000 ) {
4861                                 scale *= 10;
4862                                 num = (num*10) + (ch-'0');
4863                         }
4864                 } else {
4865                         break;
4866                 }
4867                 cp++;
4868         }
4869         *cp_p = cp;
4870
4871         /* user says num divided by scale and we say internally that
4872          * is MAX_SCORE * num / scale.
4873          */
4874         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4875 }
4876
4877 static int diff_scoreopt_parse(const char *opt)
4878 {
4879         int opt1, opt2, cmd;
4880
4881         if (*opt++ != '-')
4882                 return -1;
4883         cmd = *opt++;
4884         if (cmd == '-') {
4885                 /* convert the long-form arguments into short-form versions */
4886                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4887                         if (*opt == 0 || *opt++ == '=')
4888                                 cmd = 'B';
4889                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4890                         if (*opt == 0 || *opt++ == '=')
4891                                 cmd = 'C';
4892                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4893                         if (*opt == 0 || *opt++ == '=')
4894                                 cmd = 'M';
4895                 }
4896         }
4897         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4898                 return -1; /* that is not a -M, -C, or -B option */
4899
4900         opt1 = parse_rename_score(&opt);
4901         if (cmd != 'B')
4902                 opt2 = 0;
4903         else {
4904                 if (*opt == 0)
4905                         opt2 = 0;
4906                 else if (*opt != '/')
4907                         return -1; /* we expect -B80/99 or -B80 */
4908                 else {
4909                         opt++;
4910                         opt2 = parse_rename_score(&opt);
4911                 }
4912         }
4913         if (*opt != 0)
4914                 return -1;
4915         return opt1 | (opt2 << 16);
4916 }
4917
4918 struct diff_queue_struct diff_queued_diff;
4919
4920 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4921 {
4922         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4923         queue->queue[queue->nr++] = dp;
4924 }
4925
4926 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4927                                  struct diff_filespec *one,
4928                                  struct diff_filespec *two)
4929 {
4930         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4931         dp->one = one;
4932         dp->two = two;
4933         if (queue)
4934                 diff_q(queue, dp);
4935         return dp;
4936 }
4937
4938 void diff_free_filepair(struct diff_filepair *p)
4939 {
4940         free_filespec(p->one);
4941         free_filespec(p->two);
4942         free(p);
4943 }
4944
4945 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4946 {
4947         int abblen;
4948         const char *abbrev;
4949
4950         /* Do we want all 40 hex characters? */
4951         if (len == GIT_SHA1_HEXSZ)
4952                 return oid_to_hex(oid);
4953
4954         /* An abbreviated value is fine, possibly followed by an ellipsis. */
4955         abbrev = diff_abbrev_oid(oid, len);
4956
4957         if (!print_sha1_ellipsis())
4958                 return abbrev;
4959
4960         abblen = strlen(abbrev);
4961
4962         /*
4963          * In well-behaved cases, where the abbreviated result is the
4964          * same as the requested length, append three dots after the
4965          * abbreviation (hence the whole logic is limited to the case
4966          * where abblen < 37); when the actual abbreviated result is a
4967          * bit longer than the requested length, we reduce the number
4968          * of dots so that they match the well-behaved ones.  However,
4969          * if the actual abbreviation is longer than the requested
4970          * length by more than three, we give up on aligning, and add
4971          * three dots anyway, to indicate that the output is not the
4972          * full object name.  Yes, this may be suboptimal, but this
4973          * appears only in "diff --raw --abbrev" output and it is not
4974          * worth the effort to change it now.  Note that this would
4975          * likely to work fine when the automatic sizing of default
4976          * abbreviation length is used--we would be fed -1 in "len" in
4977          * that case, and will end up always appending three-dots, but
4978          * the automatic sizing is supposed to give abblen that ensures
4979          * uniqueness across all objects (statistically speaking).
4980          */
4981         if (abblen < GIT_SHA1_HEXSZ - 3) {
4982                 static char hex[GIT_MAX_HEXSZ + 1];
4983                 if (len < abblen && abblen <= len + 2)
4984                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4985                 else
4986                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4987                 return hex;
4988         }
4989
4990         return oid_to_hex(oid);
4991 }
4992
4993 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4994 {
4995         int line_termination = opt->line_termination;
4996         int inter_name_termination = line_termination ? '\t' : '\0';
4997
4998         fprintf(opt->file, "%s", diff_line_prefix(opt));
4999         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5000                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5001                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5002                 fprintf(opt->file, "%s ",
5003                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5004         }
5005         if (p->score) {
5006                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5007                         inter_name_termination);
5008         } else {
5009                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5010         }
5011
5012         if (p->status == DIFF_STATUS_COPIED ||
5013             p->status == DIFF_STATUS_RENAMED) {
5014                 const char *name_a, *name_b;
5015                 name_a = p->one->path;
5016                 name_b = p->two->path;
5017                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5018                 write_name_quoted(name_a, opt->file, inter_name_termination);
5019                 write_name_quoted(name_b, opt->file, line_termination);
5020         } else {
5021                 const char *name_a, *name_b;
5022                 name_a = p->one->mode ? p->one->path : p->two->path;
5023                 name_b = NULL;
5024                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5025                 write_name_quoted(name_a, opt->file, line_termination);
5026         }
5027 }
5028
5029 int diff_unmodified_pair(struct diff_filepair *p)
5030 {
5031         /* This function is written stricter than necessary to support
5032          * the currently implemented transformers, but the idea is to
5033          * let transformers to produce diff_filepairs any way they want,
5034          * and filter and clean them up here before producing the output.
5035          */
5036         struct diff_filespec *one = p->one, *two = p->two;
5037
5038         if (DIFF_PAIR_UNMERGED(p))
5039                 return 0; /* unmerged is interesting */
5040
5041         /* deletion, addition, mode or type change
5042          * and rename are all interesting.
5043          */
5044         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5045             DIFF_PAIR_MODE_CHANGED(p) ||
5046             strcmp(one->path, two->path))
5047                 return 0;
5048
5049         /* both are valid and point at the same path.  that is, we are
5050          * dealing with a change.
5051          */
5052         if (one->oid_valid && two->oid_valid &&
5053             !oidcmp(&one->oid, &two->oid) &&
5054             !one->dirty_submodule && !two->dirty_submodule)
5055                 return 1; /* no change */
5056         if (!one->oid_valid && !two->oid_valid)
5057                 return 1; /* both look at the same file on the filesystem. */
5058         return 0;
5059 }
5060
5061 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5062 {
5063         if (diff_unmodified_pair(p))
5064                 return;
5065
5066         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5067             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5068                 return; /* no tree diffs in patch format */
5069
5070         run_diff(p, o);
5071 }
5072
5073 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5074                             struct diffstat_t *diffstat)
5075 {
5076         if (diff_unmodified_pair(p))
5077                 return;
5078
5079         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5080             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5081                 return; /* no useful stat for tree diffs */
5082
5083         run_diffstat(p, o, diffstat);
5084 }
5085
5086 static void diff_flush_checkdiff(struct diff_filepair *p,
5087                 struct diff_options *o)
5088 {
5089         if (diff_unmodified_pair(p))
5090                 return;
5091
5092         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5093             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5094                 return; /* nothing to check in tree diffs */
5095
5096         run_checkdiff(p, o);
5097 }
5098
5099 int diff_queue_is_empty(void)
5100 {
5101         struct diff_queue_struct *q = &diff_queued_diff;
5102         int i;
5103         for (i = 0; i < q->nr; i++)
5104                 if (!diff_unmodified_pair(q->queue[i]))
5105                         return 0;
5106         return 1;
5107 }
5108
5109 #if DIFF_DEBUG
5110 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5111 {
5112         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5113                 x, one ? one : "",
5114                 s->path,
5115                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5116                 s->mode,
5117                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5118         fprintf(stderr, "queue[%d] %s size %lu\n",
5119                 x, one ? one : "",
5120                 s->size);
5121 }
5122
5123 void diff_debug_filepair(const struct diff_filepair *p, int i)
5124 {
5125         diff_debug_filespec(p->one, i, "one");
5126         diff_debug_filespec(p->two, i, "two");
5127         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5128                 p->score, p->status ? p->status : '?',
5129                 p->one->rename_used, p->broken_pair);
5130 }
5131
5132 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5133 {
5134         int i;
5135         if (msg)
5136                 fprintf(stderr, "%s\n", msg);
5137         fprintf(stderr, "q->nr = %d\n", q->nr);
5138         for (i = 0; i < q->nr; i++) {
5139                 struct diff_filepair *p = q->queue[i];
5140                 diff_debug_filepair(p, i);
5141         }
5142 }
5143 #endif
5144
5145 static void diff_resolve_rename_copy(void)
5146 {
5147         int i;
5148         struct diff_filepair *p;
5149         struct diff_queue_struct *q = &diff_queued_diff;
5150
5151         diff_debug_queue("resolve-rename-copy", q);
5152
5153         for (i = 0; i < q->nr; i++) {
5154                 p = q->queue[i];
5155                 p->status = 0; /* undecided */
5156                 if (DIFF_PAIR_UNMERGED(p))
5157                         p->status = DIFF_STATUS_UNMERGED;
5158                 else if (!DIFF_FILE_VALID(p->one))
5159                         p->status = DIFF_STATUS_ADDED;
5160                 else if (!DIFF_FILE_VALID(p->two))
5161                         p->status = DIFF_STATUS_DELETED;
5162                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5163                         p->status = DIFF_STATUS_TYPE_CHANGED;
5164
5165                 /* from this point on, we are dealing with a pair
5166                  * whose both sides are valid and of the same type, i.e.
5167                  * either in-place edit or rename/copy edit.
5168                  */
5169                 else if (DIFF_PAIR_RENAME(p)) {
5170                         /*
5171                          * A rename might have re-connected a broken
5172                          * pair up, causing the pathnames to be the
5173                          * same again. If so, that's not a rename at
5174                          * all, just a modification..
5175                          *
5176                          * Otherwise, see if this source was used for
5177                          * multiple renames, in which case we decrement
5178                          * the count, and call it a copy.
5179                          */
5180                         if (!strcmp(p->one->path, p->two->path))
5181                                 p->status = DIFF_STATUS_MODIFIED;
5182                         else if (--p->one->rename_used > 0)
5183                                 p->status = DIFF_STATUS_COPIED;
5184                         else
5185                                 p->status = DIFF_STATUS_RENAMED;
5186                 }
5187                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
5188                          p->one->mode != p->two->mode ||
5189                          p->one->dirty_submodule ||
5190                          p->two->dirty_submodule ||
5191                          is_null_oid(&p->one->oid))
5192                         p->status = DIFF_STATUS_MODIFIED;
5193                 else {
5194                         /* This is a "no-change" entry and should not
5195                          * happen anymore, but prepare for broken callers.
5196                          */
5197                         error("feeding unmodified %s to diffcore",
5198                               p->one->path);
5199                         p->status = DIFF_STATUS_UNKNOWN;
5200                 }
5201         }
5202         diff_debug_queue("resolve-rename-copy done", q);
5203 }
5204
5205 static int check_pair_status(struct diff_filepair *p)
5206 {
5207         switch (p->status) {
5208         case DIFF_STATUS_UNKNOWN:
5209                 return 0;
5210         case 0:
5211                 die("internal error in diff-resolve-rename-copy");
5212         default:
5213                 return 1;
5214         }
5215 }
5216
5217 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5218 {
5219         int fmt = opt->output_format;
5220
5221         if (fmt & DIFF_FORMAT_CHECKDIFF)
5222                 diff_flush_checkdiff(p, opt);
5223         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5224                 diff_flush_raw(p, opt);
5225         else if (fmt & DIFF_FORMAT_NAME) {
5226                 const char *name_a, *name_b;
5227                 name_a = p->two->path;
5228                 name_b = NULL;
5229                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5230                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5231                 write_name_quoted(name_a, opt->file, opt->line_termination);
5232         }
5233 }
5234
5235 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5236 {
5237         struct strbuf sb = STRBUF_INIT;
5238         if (fs->mode)
5239                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5240         else
5241                 strbuf_addf(&sb, " %s ", newdelete);
5242
5243         quote_c_style(fs->path, &sb, NULL, 0);
5244         strbuf_addch(&sb, '\n');
5245         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5246                          sb.buf, sb.len, 0);
5247         strbuf_release(&sb);
5248 }
5249
5250 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5251                 int show_name)
5252 {
5253         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5254                 struct strbuf sb = STRBUF_INIT;
5255                 strbuf_addf(&sb, " mode change %06o => %06o",
5256                             p->one->mode, p->two->mode);
5257                 if (show_name) {
5258                         strbuf_addch(&sb, ' ');
5259                         quote_c_style(p->two->path, &sb, NULL, 0);
5260                 }
5261                 strbuf_addch(&sb, '\n');
5262                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5263                                  sb.buf, sb.len, 0);
5264                 strbuf_release(&sb);
5265         }
5266 }
5267
5268 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5269                 struct diff_filepair *p)
5270 {
5271         struct strbuf sb = STRBUF_INIT;
5272         struct strbuf names = STRBUF_INIT;
5273
5274         pprint_rename(&names, p->one->path, p->two->path);
5275         strbuf_addf(&sb, " %s %s (%d%%)\n",
5276                     renamecopy, names.buf, similarity_index(p));
5277         strbuf_release(&names);
5278         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5279                                  sb.buf, sb.len, 0);
5280         show_mode_change(opt, p, 0);
5281         strbuf_release(&sb);
5282 }
5283
5284 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5285 {
5286         switch(p->status) {
5287         case DIFF_STATUS_DELETED:
5288                 show_file_mode_name(opt, "delete", p->one);
5289                 break;
5290         case DIFF_STATUS_ADDED:
5291                 show_file_mode_name(opt, "create", p->two);
5292                 break;
5293         case DIFF_STATUS_COPIED:
5294                 show_rename_copy(opt, "copy", p);
5295                 break;
5296         case DIFF_STATUS_RENAMED:
5297                 show_rename_copy(opt, "rename", p);
5298                 break;
5299         default:
5300                 if (p->score) {
5301                         struct strbuf sb = STRBUF_INIT;
5302                         strbuf_addstr(&sb, " rewrite ");
5303                         quote_c_style(p->two->path, &sb, NULL, 0);
5304                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5305                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5306                                          sb.buf, sb.len, 0);
5307                         strbuf_release(&sb);
5308                 }
5309                 show_mode_change(opt, p, !p->score);
5310                 break;
5311         }
5312 }
5313
5314 struct patch_id_t {
5315         git_SHA_CTX *ctx;
5316         int patchlen;
5317 };
5318
5319 static int remove_space(char *line, int len)
5320 {
5321         int i;
5322         char *dst = line;
5323         unsigned char c;
5324
5325         for (i = 0; i < len; i++)
5326                 if (!isspace((c = line[i])))
5327                         *dst++ = c;
5328
5329         return dst - line;
5330 }
5331
5332 static void patch_id_consume(void *priv, char *line, unsigned long len)
5333 {
5334         struct patch_id_t *data = priv;
5335         int new_len;
5336
5337         /* Ignore line numbers when computing the SHA1 of the patch */
5338         if (starts_with(line, "@@ -"))
5339                 return;
5340
5341         new_len = remove_space(line, len);
5342
5343         git_SHA1_Update(data->ctx, line, new_len);
5344         data->patchlen += new_len;
5345 }
5346
5347 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5348 {
5349         git_SHA1_Update(ctx, str, strlen(str));
5350 }
5351
5352 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5353 {
5354         /* large enough for 2^32 in octal */
5355         char buf[12];
5356         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5357         git_SHA1_Update(ctx, buf, len);
5358 }
5359
5360 /* returns 0 upon success, and writes result into sha1 */
5361 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5362 {
5363         struct diff_queue_struct *q = &diff_queued_diff;
5364         int i;
5365         git_SHA_CTX ctx;
5366         struct patch_id_t data;
5367
5368         git_SHA1_Init(&ctx);
5369         memset(&data, 0, sizeof(struct patch_id_t));
5370         data.ctx = &ctx;
5371
5372         for (i = 0; i < q->nr; i++) {
5373                 xpparam_t xpp;
5374                 xdemitconf_t xecfg;
5375                 mmfile_t mf1, mf2;
5376                 struct diff_filepair *p = q->queue[i];
5377                 int len1, len2;
5378
5379                 memset(&xpp, 0, sizeof(xpp));
5380                 memset(&xecfg, 0, sizeof(xecfg));
5381                 if (p->status == 0)
5382                         return error("internal diff status error");
5383                 if (p->status == DIFF_STATUS_UNKNOWN)
5384                         continue;
5385                 if (diff_unmodified_pair(p))
5386                         continue;
5387                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5388                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5389                         continue;
5390                 if (DIFF_PAIR_UNMERGED(p))
5391                         continue;
5392
5393                 diff_fill_oid_info(p->one);
5394                 diff_fill_oid_info(p->two);
5395
5396                 len1 = remove_space(p->one->path, strlen(p->one->path));
5397                 len2 = remove_space(p->two->path, strlen(p->two->path));
5398                 patch_id_add_string(&ctx, "diff--git");
5399                 patch_id_add_string(&ctx, "a/");
5400                 git_SHA1_Update(&ctx, p->one->path, len1);
5401                 patch_id_add_string(&ctx, "b/");
5402                 git_SHA1_Update(&ctx, p->two->path, len2);
5403
5404                 if (p->one->mode == 0) {
5405                         patch_id_add_string(&ctx, "newfilemode");
5406                         patch_id_add_mode(&ctx, p->two->mode);
5407                         patch_id_add_string(&ctx, "---/dev/null");
5408                         patch_id_add_string(&ctx, "+++b/");
5409                         git_SHA1_Update(&ctx, p->two->path, len2);
5410                 } else if (p->two->mode == 0) {
5411                         patch_id_add_string(&ctx, "deletedfilemode");
5412                         patch_id_add_mode(&ctx, p->one->mode);
5413                         patch_id_add_string(&ctx, "---a/");
5414                         git_SHA1_Update(&ctx, p->one->path, len1);
5415                         patch_id_add_string(&ctx, "+++/dev/null");
5416                 } else {
5417                         patch_id_add_string(&ctx, "---a/");
5418                         git_SHA1_Update(&ctx, p->one->path, len1);
5419                         patch_id_add_string(&ctx, "+++b/");
5420                         git_SHA1_Update(&ctx, p->two->path, len2);
5421                 }
5422
5423                 if (diff_header_only)
5424                         continue;
5425
5426                 if (fill_mmfile(&mf1, p->one) < 0 ||
5427                     fill_mmfile(&mf2, p->two) < 0)
5428                         return error("unable to read files to diff");
5429
5430                 if (diff_filespec_is_binary(p->one) ||
5431                     diff_filespec_is_binary(p->two)) {
5432                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5433                                         GIT_SHA1_HEXSZ);
5434                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5435                                         GIT_SHA1_HEXSZ);
5436                         continue;
5437                 }
5438
5439                 xpp.flags = 0;
5440                 xecfg.ctxlen = 3;
5441                 xecfg.flags = 0;
5442                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
5443                                   &xpp, &xecfg))
5444                         return error("unable to generate patch-id diff for %s",
5445                                      p->one->path);
5446         }
5447
5448         git_SHA1_Final(oid->hash, &ctx);
5449         return 0;
5450 }
5451
5452 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5453 {
5454         struct diff_queue_struct *q = &diff_queued_diff;
5455         int i;
5456         int result = diff_get_patch_id(options, oid, diff_header_only);
5457
5458         for (i = 0; i < q->nr; i++)
5459                 diff_free_filepair(q->queue[i]);
5460
5461         free(q->queue);
5462         DIFF_QUEUE_CLEAR(q);
5463
5464         return result;
5465 }
5466
5467 static int is_summary_empty(const struct diff_queue_struct *q)
5468 {
5469         int i;
5470
5471         for (i = 0; i < q->nr; i++) {
5472                 const struct diff_filepair *p = q->queue[i];
5473
5474                 switch (p->status) {
5475                 case DIFF_STATUS_DELETED:
5476                 case DIFF_STATUS_ADDED:
5477                 case DIFF_STATUS_COPIED:
5478                 case DIFF_STATUS_RENAMED:
5479                         return 0;
5480                 default:
5481                         if (p->score)
5482                                 return 0;
5483                         if (p->one->mode && p->two->mode &&
5484                             p->one->mode != p->two->mode)
5485                                 return 0;
5486                         break;
5487                 }
5488         }
5489         return 1;
5490 }
5491
5492 static const char rename_limit_warning[] =
5493 N_("inexact rename detection was skipped due to too many files.");
5494
5495 static const char degrade_cc_to_c_warning[] =
5496 N_("only found copies from modified paths due to too many files.");
5497
5498 static const char rename_limit_advice[] =
5499 N_("you may want to set your %s variable to at least "
5500    "%d and retry the command.");
5501
5502 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5503 {
5504         fflush(stdout);
5505         if (degraded_cc)
5506                 warning(_(degrade_cc_to_c_warning));
5507         else if (needed)
5508                 warning(_(rename_limit_warning));
5509         else
5510                 return;
5511         if (0 < needed)
5512                 warning(_(rename_limit_advice), varname, needed);
5513 }
5514
5515 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5516 {
5517         int i;
5518         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5519         struct diff_queue_struct *q = &diff_queued_diff;
5520
5521         if (WSEH_NEW & WS_RULE_MASK)
5522                 BUG("WS rules bit mask overlaps with diff symbol flags");
5523
5524         if (o->color_moved)
5525                 o->emitted_symbols = &esm;
5526
5527         for (i = 0; i < q->nr; i++) {
5528                 struct diff_filepair *p = q->queue[i];
5529                 if (check_pair_status(p))
5530                         diff_flush_patch(p, o);
5531         }
5532
5533         if (o->emitted_symbols) {
5534                 if (o->color_moved) {
5535                         struct hashmap add_lines, del_lines;
5536
5537                         hashmap_init(&del_lines,
5538                                      (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5539                         hashmap_init(&add_lines,
5540                                      (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5541
5542                         add_lines_to_move_detection(o, &add_lines, &del_lines);
5543                         mark_color_as_moved(o, &add_lines, &del_lines);
5544                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5545                                 dim_moved_lines(o);
5546
5547                         hashmap_free(&add_lines, 0);
5548                         hashmap_free(&del_lines, 0);
5549                 }
5550
5551                 for (i = 0; i < esm.nr; i++)
5552                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
5553
5554                 for (i = 0; i < esm.nr; i++)
5555                         free((void *)esm.buf[i].line);
5556         }
5557         esm.nr = 0;
5558 }
5559
5560 void diff_flush(struct diff_options *options)
5561 {
5562         struct diff_queue_struct *q = &diff_queued_diff;
5563         int i, output_format = options->output_format;
5564         int separator = 0;
5565         int dirstat_by_line = 0;
5566
5567         /*
5568          * Order: raw, stat, summary, patch
5569          * or:    name/name-status/checkdiff (other bits clear)
5570          */
5571         if (!q->nr)
5572                 goto free_queue;
5573
5574         if (output_format & (DIFF_FORMAT_RAW |
5575                              DIFF_FORMAT_NAME |
5576                              DIFF_FORMAT_NAME_STATUS |
5577                              DIFF_FORMAT_CHECKDIFF)) {
5578                 for (i = 0; i < q->nr; i++) {
5579                         struct diff_filepair *p = q->queue[i];
5580                         if (check_pair_status(p))
5581                                 flush_one_pair(p, options);
5582                 }
5583                 separator++;
5584         }
5585
5586         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
5587                 dirstat_by_line = 1;
5588
5589         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5590             dirstat_by_line) {
5591                 struct diffstat_t diffstat;
5592
5593                 memset(&diffstat, 0, sizeof(struct diffstat_t));
5594                 for (i = 0; i < q->nr; i++) {
5595                         struct diff_filepair *p = q->queue[i];
5596                         if (check_pair_status(p))
5597                                 diff_flush_stat(p, options, &diffstat);
5598                 }
5599                 if (output_format & DIFF_FORMAT_NUMSTAT)
5600                         show_numstat(&diffstat, options);
5601                 if (output_format & DIFF_FORMAT_DIFFSTAT)
5602                         show_stats(&diffstat, options);
5603                 if (output_format & DIFF_FORMAT_SHORTSTAT)
5604                         show_shortstats(&diffstat, options);
5605                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5606                         show_dirstat_by_line(&diffstat, options);
5607                 free_diffstat_info(&diffstat);
5608                 separator++;
5609         }
5610         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5611                 show_dirstat(options);
5612
5613         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5614                 for (i = 0; i < q->nr; i++) {
5615                         diff_summary(options, q->queue[i]);
5616                 }
5617                 separator++;
5618         }
5619
5620         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5621             options->flags.exit_with_status &&
5622             options->flags.diff_from_contents) {
5623                 /*
5624                  * run diff_flush_patch for the exit status. setting
5625                  * options->file to /dev/null should be safe, because we
5626                  * aren't supposed to produce any output anyway.
5627                  */
5628                 if (options->close_file)
5629                         fclose(options->file);
5630                 options->file = xfopen("/dev/null", "w");
5631                 options->close_file = 1;
5632                 options->color_moved = 0;
5633                 for (i = 0; i < q->nr; i++) {
5634                         struct diff_filepair *p = q->queue[i];
5635                         if (check_pair_status(p))
5636                                 diff_flush_patch(p, options);
5637                         if (options->found_changes)
5638                                 break;
5639                 }
5640         }
5641
5642         if (output_format & DIFF_FORMAT_PATCH) {
5643                 if (separator) {
5644                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5645                         if (options->stat_sep)
5646                                 /* attach patch instead of inline */
5647                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5648                                                  NULL, 0, 0);
5649                 }
5650
5651                 diff_flush_patch_all_file_pairs(options);
5652         }
5653
5654         if (output_format & DIFF_FORMAT_CALLBACK)
5655                 options->format_callback(q, options, options->format_callback_data);
5656
5657         for (i = 0; i < q->nr; i++)
5658                 diff_free_filepair(q->queue[i]);
5659 free_queue:
5660         free(q->queue);
5661         DIFF_QUEUE_CLEAR(q);
5662         if (options->close_file)
5663                 fclose(options->file);
5664
5665         /*
5666          * Report the content-level differences with HAS_CHANGES;
5667          * diff_addremove/diff_change does not set the bit when
5668          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
5669          */
5670         if (options->flags.diff_from_contents) {
5671                 if (options->found_changes)
5672                         options->flags.has_changes = 1;
5673                 else
5674                         options->flags.has_changes = 0;
5675         }
5676 }
5677
5678 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
5679 {
5680         return (((p->status == DIFF_STATUS_MODIFIED) &&
5681                  ((p->score &&
5682                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
5683                   (!p->score &&
5684                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
5685                 ((p->status != DIFF_STATUS_MODIFIED) &&
5686                  filter_bit_tst(p->status, options)));
5687 }
5688
5689 static void diffcore_apply_filter(struct diff_options *options)
5690 {
5691         int i;
5692         struct diff_queue_struct *q = &diff_queued_diff;
5693         struct diff_queue_struct outq;
5694
5695         DIFF_QUEUE_CLEAR(&outq);
5696
5697         if (!options->filter)
5698                 return;
5699
5700         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
5701                 int found;
5702                 for (i = found = 0; !found && i < q->nr; i++) {
5703                         if (match_filter(options, q->queue[i]))
5704                                 found++;
5705                 }
5706                 if (found)
5707                         return;
5708
5709                 /* otherwise we will clear the whole queue
5710                  * by copying the empty outq at the end of this
5711                  * function, but first clear the current entries
5712                  * in the queue.
5713                  */
5714                 for (i = 0; i < q->nr; i++)
5715                         diff_free_filepair(q->queue[i]);
5716         }
5717         else {
5718                 /* Only the matching ones */
5719                 for (i = 0; i < q->nr; i++) {
5720                         struct diff_filepair *p = q->queue[i];
5721                         if (match_filter(options, p))
5722                                 diff_q(&outq, p);
5723                         else
5724                                 diff_free_filepair(p);
5725                 }
5726         }
5727         free(q->queue);
5728         *q = outq;
5729 }
5730
5731 /* Check whether two filespecs with the same mode and size are identical */
5732 static int diff_filespec_is_identical(struct diff_filespec *one,
5733                                       struct diff_filespec *two)
5734 {
5735         if (S_ISGITLINK(one->mode))
5736                 return 0;
5737         if (diff_populate_filespec(one, 0))
5738                 return 0;
5739         if (diff_populate_filespec(two, 0))
5740                 return 0;
5741         return !memcmp(one->data, two->data, one->size);
5742 }
5743
5744 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5745 {
5746         if (p->done_skip_stat_unmatch)
5747                 return p->skip_stat_unmatch_result;
5748
5749         p->done_skip_stat_unmatch = 1;
5750         p->skip_stat_unmatch_result = 0;
5751         /*
5752          * 1. Entries that come from stat info dirtiness
5753          *    always have both sides (iow, not create/delete),
5754          *    one side of the object name is unknown, with
5755          *    the same mode and size.  Keep the ones that
5756          *    do not match these criteria.  They have real
5757          *    differences.
5758          *
5759          * 2. At this point, the file is known to be modified,
5760          *    with the same mode and size, and the object
5761          *    name of one side is unknown.  Need to inspect
5762          *    the identical contents.
5763          */
5764         if (!DIFF_FILE_VALID(p->one) || /* (1) */
5765             !DIFF_FILE_VALID(p->two) ||
5766             (p->one->oid_valid && p->two->oid_valid) ||
5767             (p->one->mode != p->two->mode) ||
5768             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5769             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5770             (p->one->size != p->two->size) ||
5771             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5772                 p->skip_stat_unmatch_result = 1;
5773         return p->skip_stat_unmatch_result;
5774 }
5775
5776 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5777 {
5778         int i;
5779         struct diff_queue_struct *q = &diff_queued_diff;
5780         struct diff_queue_struct outq;
5781         DIFF_QUEUE_CLEAR(&outq);
5782
5783         for (i = 0; i < q->nr; i++) {
5784                 struct diff_filepair *p = q->queue[i];
5785
5786                 if (diff_filespec_check_stat_unmatch(p))
5787                         diff_q(&outq, p);
5788                 else {
5789                         /*
5790                          * The caller can subtract 1 from skip_stat_unmatch
5791                          * to determine how many paths were dirty only
5792                          * due to stat info mismatch.
5793                          */
5794                         if (!diffopt->flags.no_index)
5795                                 diffopt->skip_stat_unmatch++;
5796                         diff_free_filepair(p);
5797                 }
5798         }
5799         free(q->queue);
5800         *q = outq;
5801 }
5802
5803 static int diffnamecmp(const void *a_, const void *b_)
5804 {
5805         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5806         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5807         const char *name_a, *name_b;
5808
5809         name_a = a->one ? a->one->path : a->two->path;
5810         name_b = b->one ? b->one->path : b->two->path;
5811         return strcmp(name_a, name_b);
5812 }
5813
5814 void diffcore_fix_diff_index(struct diff_options *options)
5815 {
5816         struct diff_queue_struct *q = &diff_queued_diff;
5817         QSORT(q->queue, q->nr, diffnamecmp);
5818 }
5819
5820 void diffcore_std(struct diff_options *options)
5821 {
5822         /* NOTE please keep the following in sync with diff_tree_combined() */
5823         if (options->skip_stat_unmatch)
5824                 diffcore_skip_stat_unmatch(options);
5825         if (!options->found_follow) {
5826                 /* See try_to_follow_renames() in tree-diff.c */
5827                 if (options->break_opt != -1)
5828                         diffcore_break(options->break_opt);
5829                 if (options->detect_rename)
5830                         diffcore_rename(options);
5831                 if (options->break_opt != -1)
5832                         diffcore_merge_broken();
5833         }
5834         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
5835                 diffcore_pickaxe(options);
5836         if (options->orderfile)
5837                 diffcore_order(options->orderfile);
5838         if (!options->found_follow)
5839                 /* See try_to_follow_renames() in tree-diff.c */
5840                 diff_resolve_rename_copy();
5841         diffcore_apply_filter(options);
5842
5843         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
5844                 options->flags.has_changes = 1;
5845         else
5846                 options->flags.has_changes = 0;
5847
5848         options->found_follow = 0;
5849 }
5850
5851 int diff_result_code(struct diff_options *opt, int status)
5852 {
5853         int result = 0;
5854
5855         diff_warn_rename_limit("diff.renameLimit",
5856                                opt->needed_rename_limit,
5857                                opt->degraded_cc_to_c);
5858         if (!opt->flags.exit_with_status &&
5859             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5860                 return status;
5861         if (opt->flags.exit_with_status &&
5862             opt->flags.has_changes)
5863                 result |= 01;
5864         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5865             opt->flags.check_failed)
5866                 result |= 02;
5867         return result;
5868 }
5869
5870 int diff_can_quit_early(struct diff_options *opt)
5871 {
5872         return (opt->flags.quick &&
5873                 !opt->filter &&
5874                 opt->flags.has_changes);
5875 }
5876
5877 /*
5878  * Shall changes to this submodule be ignored?
5879  *
5880  * Submodule changes can be configured to be ignored separately for each path,
5881  * but that configuration can be overridden from the command line.
5882  */
5883 static int is_submodule_ignored(const char *path, struct diff_options *options)
5884 {
5885         int ignored = 0;
5886         struct diff_flags orig_flags = options->flags;
5887         if (!options->flags.override_submodule_config)
5888                 set_diffopt_flags_from_submodule_config(options, path);
5889         if (options->flags.ignore_submodules)
5890                 ignored = 1;
5891         options->flags = orig_flags;
5892         return ignored;
5893 }
5894
5895 void diff_addremove(struct diff_options *options,
5896                     int addremove, unsigned mode,
5897                     const struct object_id *oid,
5898                     int oid_valid,
5899                     const char *concatpath, unsigned dirty_submodule)
5900 {
5901         struct diff_filespec *one, *two;
5902
5903         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5904                 return;
5905
5906         /* This may look odd, but it is a preparation for
5907          * feeding "there are unchanged files which should
5908          * not produce diffs, but when you are doing copy
5909          * detection you would need them, so here they are"
5910          * entries to the diff-core.  They will be prefixed
5911          * with something like '=' or '*' (I haven't decided
5912          * which but should not make any difference).
5913          * Feeding the same new and old to diff_change()
5914          * also has the same effect.
5915          * Before the final output happens, they are pruned after
5916          * merged into rename/copy pairs as appropriate.
5917          */
5918         if (options->flags.reverse_diff)
5919                 addremove = (addremove == '+' ? '-' :
5920                              addremove == '-' ? '+' : addremove);
5921
5922         if (options->prefix &&
5923             strncmp(concatpath, options->prefix, options->prefix_length))
5924                 return;
5925
5926         one = alloc_filespec(concatpath);
5927         two = alloc_filespec(concatpath);
5928
5929         if (addremove != '+')
5930                 fill_filespec(one, oid, oid_valid, mode);
5931         if (addremove != '-') {
5932                 fill_filespec(two, oid, oid_valid, mode);
5933                 two->dirty_submodule = dirty_submodule;
5934         }
5935
5936         diff_queue(&diff_queued_diff, one, two);
5937         if (!options->flags.diff_from_contents)
5938                 options->flags.has_changes = 1;
5939 }
5940
5941 void diff_change(struct diff_options *options,
5942                  unsigned old_mode, unsigned new_mode,
5943                  const struct object_id *old_oid,
5944                  const struct object_id *new_oid,
5945                  int old_oid_valid, int new_oid_valid,
5946                  const char *concatpath,
5947                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5948 {
5949         struct diff_filespec *one, *two;
5950         struct diff_filepair *p;
5951
5952         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5953             is_submodule_ignored(concatpath, options))
5954                 return;
5955
5956         if (options->flags.reverse_diff) {
5957                 SWAP(old_mode, new_mode);
5958                 SWAP(old_oid, new_oid);
5959                 SWAP(old_oid_valid, new_oid_valid);
5960                 SWAP(old_dirty_submodule, new_dirty_submodule);
5961         }
5962
5963         if (options->prefix &&
5964             strncmp(concatpath, options->prefix, options->prefix_length))
5965                 return;
5966
5967         one = alloc_filespec(concatpath);
5968         two = alloc_filespec(concatpath);
5969         fill_filespec(one, old_oid, old_oid_valid, old_mode);
5970         fill_filespec(two, new_oid, new_oid_valid, new_mode);
5971         one->dirty_submodule = old_dirty_submodule;
5972         two->dirty_submodule = new_dirty_submodule;
5973         p = diff_queue(&diff_queued_diff, one, two);
5974
5975         if (options->flags.diff_from_contents)
5976                 return;
5977
5978         if (options->flags.quick && options->skip_stat_unmatch &&
5979             !diff_filespec_check_stat_unmatch(p))
5980                 return;
5981
5982         options->flags.has_changes = 1;
5983 }
5984
5985 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5986 {
5987         struct diff_filepair *pair;
5988         struct diff_filespec *one, *two;
5989
5990         if (options->prefix &&
5991             strncmp(path, options->prefix, options->prefix_length))
5992                 return NULL;
5993
5994         one = alloc_filespec(path);
5995         two = alloc_filespec(path);
5996         pair = diff_queue(&diff_queued_diff, one, two);
5997         pair->is_unmerged = 1;
5998         return pair;
5999 }
6000
6001 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
6002                 size_t *outsize)
6003 {
6004         struct diff_tempfile *temp;
6005         const char *argv[3];
6006         const char **arg = argv;
6007         struct child_process child = CHILD_PROCESS_INIT;
6008         struct strbuf buf = STRBUF_INIT;
6009         int err = 0;
6010
6011         temp = prepare_temp_file(spec->path, spec);
6012         *arg++ = pgm;
6013         *arg++ = temp->name;
6014         *arg = NULL;
6015
6016         child.use_shell = 1;
6017         child.argv = argv;
6018         child.out = -1;
6019         if (start_command(&child)) {
6020                 remove_tempfile();
6021                 return NULL;
6022         }
6023
6024         if (strbuf_read(&buf, child.out, 0) < 0)
6025                 err = error("error reading from textconv command '%s'", pgm);
6026         close(child.out);
6027
6028         if (finish_command(&child) || err) {
6029                 strbuf_release(&buf);
6030                 remove_tempfile();
6031                 return NULL;
6032         }
6033         remove_tempfile();
6034
6035         return strbuf_detach(&buf, outsize);
6036 }
6037
6038 size_t fill_textconv(struct userdiff_driver *driver,
6039                      struct diff_filespec *df,
6040                      char **outbuf)
6041 {
6042         size_t size;
6043
6044         if (!driver) {
6045                 if (!DIFF_FILE_VALID(df)) {
6046                         *outbuf = "";
6047                         return 0;
6048                 }
6049                 if (diff_populate_filespec(df, 0))
6050                         die("unable to read files to diff");
6051                 *outbuf = df->data;
6052                 return df->size;
6053         }
6054
6055         if (!driver->textconv)
6056                 BUG("fill_textconv called with non-textconv driver");
6057
6058         if (driver->textconv_cache && df->oid_valid) {
6059                 *outbuf = notes_cache_get(driver->textconv_cache,
6060                                           &df->oid,
6061                                           &size);
6062                 if (*outbuf)
6063                         return size;
6064         }
6065
6066         *outbuf = run_textconv(driver->textconv, df, &size);
6067         if (!*outbuf)
6068                 die("unable to read files to diff");
6069
6070         if (driver->textconv_cache && df->oid_valid) {
6071                 /* ignore errors, as we might be in a readonly repository */
6072                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6073                                 size);
6074                 /*
6075                  * we could save up changes and flush them all at the end,
6076                  * but we would need an extra call after all diffing is done.
6077                  * Since generating a cache entry is the slow path anyway,
6078                  * this extra overhead probably isn't a big deal.
6079                  */
6080                 notes_cache_write(driver->textconv_cache);
6081         }
6082
6083         return size;
6084 }
6085
6086 int textconv_object(const char *path,
6087                     unsigned mode,
6088                     const struct object_id *oid,
6089                     int oid_valid,
6090                     char **buf,
6091                     unsigned long *buf_size)
6092 {
6093         struct diff_filespec *df;
6094         struct userdiff_driver *textconv;
6095
6096         df = alloc_filespec(path);
6097         fill_filespec(df, oid, oid_valid, mode);
6098         textconv = get_textconv(df);
6099         if (!textconv) {
6100                 free_filespec(df);
6101                 return 0;
6102         }
6103
6104         *buf_size = fill_textconv(textconv, df, buf);
6105         free_filespec(df);
6106         return 1;
6107 }
6108
6109 void setup_diff_pager(struct diff_options *opt)
6110 {
6111         /*
6112          * If the user asked for our exit code, then either they want --quiet
6113          * or --exit-code. We should definitely not bother with a pager in the
6114          * former case, as we will generate no output. Since we still properly
6115          * report our exit code even when a pager is run, we _could_ run a
6116          * pager with --exit-code. But since we have not done so historically,
6117          * and because it is easy to find people oneline advising "git diff
6118          * --exit-code" in hooks and other scripts, we do not do so.
6119          */
6120         if (!opt->flags.exit_with_status &&
6121             check_pager_config("diff") != 0)
6122                 setup_pager();
6123 }