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 "userdiff.h"
  17 #include "submodule-config.h"
  18 #include "submodule.h"
  19 #include "ll-merge.h"
  20 #include "string-list.h"
  21 #include "argv-array.h"
  22 #include "graph.h"
  23
  24 #ifdef NO_FAST_WORKING_DIRECTORY
  25 #define FAST_WORKING_DIRECTORY 0
  26 #else
  27 #define FAST_WORKING_DIRECTORY 1
  28 #endif
  29
  30 static int diff_detect_rename_default;
  31 static int diff_indent_heuristic = 1;
  32 static int diff_rename_limit_default = 400;
  33 static int diff_suppress_blank_empty;
  34 static int diff_use_color_default = -1;
  35 static int diff_context_default = 3;
  36 static int diff_interhunk_context_default;
  37 static const char *diff_word_regex_cfg;
  38 static const char *external_diff_cmd_cfg;
  39 static const char *diff_order_file_cfg;
  40 int diff_auto_refresh_index = 1;
  41 static int diff_mnemonic_prefix;
  42 static int diff_no_prefix;
  43 static int diff_stat_graph_width;
  44 static int diff_dirstat_permille_default = 30;
  45 static struct diff_options default_diff_options;
  46 static long diff_algorithm;
  47 static unsigned ws_error_highlight_default = WSEH_NEW;
  48
  49 static char diff_colors[][COLOR_MAXLEN] = {
  50         GIT_COLOR_RESET,
  51         GIT_COLOR_NORMAL,       /* CONTEXT */
  52         GIT_COLOR_BOLD,         /* METAINFO */
  53         GIT_COLOR_CYAN,         /* FRAGINFO */
  54         GIT_COLOR_RED,          /* OLD */
  55         GIT_COLOR_GREEN,        /* NEW */
  56         GIT_COLOR_YELLOW,       /* COMMIT */
  57         GIT_COLOR_BG_RED,       /* WHITESPACE */
  58         GIT_COLOR_NORMAL,       /* FUNCINFO */
  59 };
  60
  61 static NORETURN void die_want_option(const char *option_name)
  62 {
  63         die(_("option '%s' requires a value"), option_name);
  64 }
  65
  66 static int parse_diff_color_slot(const char *var)
  67 {
  68         if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  69                 return DIFF_CONTEXT;
  70         if (!strcasecmp(var, "meta"))
  71                 return DIFF_METAINFO;
  72         if (!strcasecmp(var, "frag"))
  73                 return DIFF_FRAGINFO;
  74         if (!strcasecmp(var, "old"))
  75                 return DIFF_FILE_OLD;
  76         if (!strcasecmp(var, "new"))
  77                 return DIFF_FILE_NEW;
  78         if (!strcasecmp(var, "commit"))
  79                 return DIFF_COMMIT;
  80         if (!strcasecmp(var, "whitespace"))
  81                 return DIFF_WHITESPACE;
  82         if (!strcasecmp(var, "func"))
  83                 return DIFF_FUNCINFO;
  84         return -1;
  85 }
  86
  87 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  88                                 struct strbuf *errmsg)
  89 {
  90         char *params_copy = xstrdup(params_string);
  91         struct string_list params = STRING_LIST_INIT_NODUP;
  92         int ret = 0;
  93         int i;
  94
  95         if (*params_copy)
  96                 string_list_split_in_place(&params, params_copy, ',', -1);
  97         for (i = 0; i < params.nr; i++) {
  98                 const char *p = params.items[i].string;
  99                 if (!strcmp(p, "changes")) {
 100                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 101                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 102                 } else if (!strcmp(p, "lines")) {
 103                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 104                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 105                 } else if (!strcmp(p, "files")) {
 106                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 107                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 108                 } else if (!strcmp(p, "noncumulative")) {
 109                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 110                 } else if (!strcmp(p, "cumulative")) {
 111                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 112                 } else if (isdigit(*p)) {
 113                         char *end;
 114                         int permille = strtoul(p, &end, 10) * 10;
 115                         if (*end == '.' && isdigit(*++end)) {
 116                                 /* only use first digit */
 117                                 permille += *end - '0';
 118                                 /* .. and ignore any further digits */
 119                                 while (isdigit(*++end))
 120                                         ; /* nothing */
 121                         }
 122                         if (!*end)
 123                                 options->dirstat_permille = permille;
 124                         else {
 125                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 126                                             p);
 127                                 ret++;
 128                         }
 129                 } else {
 130                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 131                         ret++;
 132                 }
 133
 134         }
 135         string_list_clear(&params, 0);
 136         free(params_copy);
 137         return ret;
 138 }
 139
 140 static int parse_submodule_params(struct diff_options *options, const char *value)
 141 {
 142         if (!strcmp(value, "log"))
 143                 options->submodule_format = DIFF_SUBMODULE_LOG;
 144         else if (!strcmp(value, "short"))
 145                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 146         else if (!strcmp(value, "diff"))
 147                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 148         else
 149                 return -1;
 150         return 0;
 151 }
 152
 153 static int git_config_rename(const char *var, const char *value)
 154 {
 155         if (!value)
 156                 return DIFF_DETECT_RENAME;
 157         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 158                 return  DIFF_DETECT_COPY;
 159         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 160 }
 161
 162 long parse_algorithm_value(const char *value)
 163 {
 164         if (!value)
 165                 return -1;
 166         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 167                 return 0;
 168         else if (!strcasecmp(value, "minimal"))
 169                 return XDF_NEED_MINIMAL;
 170         else if (!strcasecmp(value, "patience"))
 171                 return XDF_PATIENCE_DIFF;
 172         else if (!strcasecmp(value, "histogram"))
 173                 return XDF_HISTOGRAM_DIFF;
 174         return -1;
 175 }
 176
 177 static int parse_one_token(const char **arg, const char *token)
 178 {
 179         const char *rest;
 180         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 181                 *arg = rest;
 182                 return 1;
 183         }
 184         return 0;
 185 }
 186
 187 static int parse_ws_error_highlight(const char *arg)
 188 {
 189         const char *orig_arg = arg;
 190         unsigned val = 0;
 191
 192         while (*arg) {
 193                 if (parse_one_token(&arg, "none"))
 194                         val = 0;
 195                 else if (parse_one_token(&arg, "default"))
 196                         val = WSEH_NEW;
 197                 else if (parse_one_token(&arg, "all"))
 198                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 199                 else if (parse_one_token(&arg, "new"))
 200                         val |= WSEH_NEW;
 201                 else if (parse_one_token(&arg, "old"))
 202                         val |= WSEH_OLD;
 203                 else if (parse_one_token(&arg, "context"))
 204                         val |= WSEH_CONTEXT;
 205                 else {
 206                         return -1 - (int)(arg - orig_arg);
 207                 }
 208                 if (*arg)
 209                         arg++;
 210         }
 211         return val;
 212 }
 213
 214 /*
 215  * These are to give UI layer defaults.
 216  * The core-level commands such as git-diff-files should
 217  * never be affected by the setting of diff.renames
 218  * the user happens to have in the configuration file.
 219  */
 220 void init_diff_ui_defaults(void)
 221 {
 222         diff_detect_rename_default = 1;
 223 }
 224
 225 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 226 {
 227         if (!strcmp(var, "diff.indentheuristic"))
 228                 diff_indent_heuristic = git_config_bool(var, value);
 229         return 0;
 230 }
 231
 232 int git_diff_ui_config(const char *var, const char *value, void *cb)
 233 {
 234         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 235                 diff_use_color_default = git_config_colorbool(var, value);
 236                 return 0;
 237         }
 238         if (!strcmp(var, "diff.context")) {
 239                 diff_context_default = git_config_int(var, value);
 240                 if (diff_context_default < 0)
 241                         return -1;
 242                 return 0;
 243         }
 244         if (!strcmp(var, "diff.interhunkcontext")) {
 245                 diff_interhunk_context_default = git_config_int(var, value);
 246                 if (diff_interhunk_context_default < 0)
 247                         return -1;
 248                 return 0;
 249         }
 250         if (!strcmp(var, "diff.renames")) {
 251                 diff_detect_rename_default = git_config_rename(var, value);
 252                 return 0;
 253         }
 254         if (!strcmp(var, "diff.autorefreshindex")) {
 255                 diff_auto_refresh_index = git_config_bool(var, value);
 256                 return 0;
 257         }
 258         if (!strcmp(var, "diff.mnemonicprefix")) {
 259                 diff_mnemonic_prefix = git_config_bool(var, value);
 260                 return 0;
 261         }
 262         if (!strcmp(var, "diff.noprefix")) {
 263                 diff_no_prefix = git_config_bool(var, value);
 264                 return 0;
 265         }
 266         if (!strcmp(var, "diff.statgraphwidth")) {
 267                 diff_stat_graph_width = git_config_int(var, value);
 268                 return 0;
 269         }
 270         if (!strcmp(var, "diff.external"))
 271                 return git_config_string(&external_diff_cmd_cfg, var, value);
 272         if (!strcmp(var, "diff.wordregex"))
 273                 return git_config_string(&diff_word_regex_cfg, var, value);
 274         if (!strcmp(var, "diff.orderfile"))
 275                 return git_config_pathname(&diff_order_file_cfg, var, value);
 276
 277         if (!strcmp(var, "diff.ignoresubmodules"))
 278                 handle_ignore_submodules_arg(&default_diff_options, value);
 279
 280         if (!strcmp(var, "diff.submodule")) {
 281                 if (parse_submodule_params(&default_diff_options, value))
 282                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 283                                 value);
 284                 return 0;
 285         }
 286
 287         if (!strcmp(var, "diff.algorithm")) {
 288                 diff_algorithm = parse_algorithm_value(value);
 289                 if (diff_algorithm < 0)
 290                         return -1;
 291                 return 0;
 292         }
 293
 294         if (!strcmp(var, "diff.wserrorhighlight")) {
 295                 int val = parse_ws_error_highlight(value);
 296                 if (val < 0)
 297                         return -1;
 298                 ws_error_highlight_default = val;
 299                 return 0;
 300         }
 301
 302         if (git_color_config(var, value, cb) < 0)
 303                 return -1;
 304
 305         return git_diff_basic_config(var, value, cb);
 306 }
 307
 308 int git_diff_basic_config(const char *var, const char *value, void *cb)
 309 {
 310         const char *name;
 311
 312         if (!strcmp(var, "diff.renamelimit")) {
 313                 diff_rename_limit_default = git_config_int(var, value);
 314                 return 0;
 315         }
 316
 317         if (userdiff_config(var, value) < 0)
 318                 return -1;
 319
 320         if (skip_prefix(var, "diff.color.", &name) ||
 321             skip_prefix(var, "color.diff.", &name)) {
 322                 int slot = parse_diff_color_slot(name);
 323                 if (slot < 0)
 324                         return 0;
 325                 if (!value)
 326                         return config_error_nonbool(var);
 327                 return color_parse(value, diff_colors[slot]);
 328         }
 329
 330         /* like GNU diff's --suppress-blank-empty option  */
 331         if (!strcmp(var, "diff.suppressblankempty") ||
 332                         /* for backwards compatibility */
 333                         !strcmp(var, "diff.suppress-blank-empty")) {
 334                 diff_suppress_blank_empty = git_config_bool(var, value);
 335                 return 0;
 336         }
 337
 338         if (!strcmp(var, "diff.dirstat")) {
 339                 struct strbuf errmsg = STRBUF_INIT;
 340                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 341                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 342                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 343                                 errmsg.buf);
 344                 strbuf_release(&errmsg);
 345                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 346                 return 0;
 347         }
 348
 349         if (starts_with(var, "submodule."))
 350                 return parse_submodule_config_option(var, value);
 351
 352         if (git_diff_heuristic_config(var, value, cb) < 0)
 353                 return -1;
 354
 355         return git_default_config(var, value, cb);
 356 }
 357
 358 static char *quote_two(const char *one, const char *two)
 359 {
 360         int need_one = quote_c_style(one, NULL, NULL, 1);
 361         int need_two = quote_c_style(two, NULL, NULL, 1);
 362         struct strbuf res = STRBUF_INIT;
 363
 364         if (need_one + need_two) {
 365                 strbuf_addch(&res, '"');
 366                 quote_c_style(one, &res, NULL, 1);
 367                 quote_c_style(two, &res, NULL, 1);
 368                 strbuf_addch(&res, '"');
 369         } else {
 370                 strbuf_addstr(&res, one);
 371                 strbuf_addstr(&res, two);
 372         }
 373         return strbuf_detach(&res, NULL);
 374 }
 375
 376 static const char *external_diff(void)
 377 {
 378         static const char *external_diff_cmd = NULL;
 379         static int done_preparing = 0;
 380
 381         if (done_preparing)
 382                 return external_diff_cmd;
 383         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 384         if (!external_diff_cmd)
 385                 external_diff_cmd = external_diff_cmd_cfg;
 386         done_preparing = 1;
 387         return external_diff_cmd;
 388 }
 389
 390 /*
 391  * Keep track of files used for diffing. Sometimes such an entry
 392  * refers to a temporary file, sometimes to an existing file, and
 393  * sometimes to "/dev/null".
 394  */
 395 static struct diff_tempfile {
 396         /*
 397          * filename external diff should read from, or NULL if this
 398          * entry is currently not in use:
 399          */
 400         const char *name;
 401
 402         char hex[GIT_MAX_HEXSZ + 1];
 403         char mode[10];
 404
 405         /*
 406          * If this diff_tempfile instance refers to a temporary file,
 407          * this tempfile object is used to manage its lifetime.
 408          */
 409         struct tempfile tempfile;
 410 } diff_temp[2];
 411
 412 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 413
 414 struct emit_callback {
 415         int color_diff;
 416         unsigned ws_rule;
 417         int blank_at_eof_in_preimage;
 418         int blank_at_eof_in_postimage;
 419         int lno_in_preimage;
 420         int lno_in_postimage;
 421         sane_truncate_fn truncate;
 422         const char **label_path;
 423         struct diff_words_data *diff_words;
 424         struct diff_options *opt;
 425         struct strbuf *header;
 426 };
 427
 428 static int count_lines(const char *data, int size)
 429 {
 430         int count, ch, completely_empty = 1, nl_just_seen = 0;
 431         count = 0;
 432         while (0 < size--) {
 433                 ch = *data++;
 434                 if (ch == '\n') {
 435                         count++;
 436                         nl_just_seen = 1;
 437                         completely_empty = 0;
 438                 }
 439                 else {
 440                         nl_just_seen = 0;
 441                         completely_empty = 0;
 442                 }
 443         }
 444         if (completely_empty)
 445                 return 0;
 446         if (!nl_just_seen)
 447                 count++; /* no trailing newline */
 448         return count;
 449 }
 450
 451 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 452 {
 453         if (!DIFF_FILE_VALID(one)) {
 454                 mf->ptr = (char *)""; /* does not matter */
 455                 mf->size = 0;
 456                 return 0;
 457         }
 458         else if (diff_populate_filespec(one, 0))
 459                 return -1;
 460
 461         mf->ptr = one->data;
 462         mf->size = one->size;
 463         return 0;
 464 }
 465
 466 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 467 static unsigned long diff_filespec_size(struct diff_filespec *one)
 468 {
 469         if (!DIFF_FILE_VALID(one))
 470                 return 0;
 471         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 472         return one->size;
 473 }
 474
 475 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 476 {
 477         char *ptr = mf->ptr;
 478         long size = mf->size;
 479         int cnt = 0;
 480
 481         if (!size)
 482                 return cnt;
 483         ptr += size - 1; /* pointing at the very end */
 484         if (*ptr != '\n')
 485                 ; /* incomplete line */
 486         else
 487                 ptr--; /* skip the last LF */
 488         while (mf->ptr < ptr) {
 489                 char *prev_eol;
 490                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 491                         if (*prev_eol == '\n')
 492                                 break;
 493                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 494                         break;
 495                 cnt++;
 496                 ptr = prev_eol - 1;
 497         }
 498         return cnt;
 499 }
 500
 501 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 502                                struct emit_callback *ecbdata)
 503 {
 504         int l1, l2, at;
 505         unsigned ws_rule = ecbdata->ws_rule;
 506         l1 = count_trailing_blank(mf1, ws_rule);
 507         l2 = count_trailing_blank(mf2, ws_rule);
 508         if (l2 <= l1) {
 509                 ecbdata->blank_at_eof_in_preimage = 0;
 510                 ecbdata->blank_at_eof_in_postimage = 0;
 511                 return;
 512         }
 513         at = count_lines(mf1->ptr, mf1->size);
 514         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 515
 516         at = count_lines(mf2->ptr, mf2->size);
 517         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 518 }
 519
 520 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 521                         int first, const char *line, int len)
 522 {
 523         int has_trailing_newline, has_trailing_carriage_return;
 524         int nofirst;
 525         FILE *file = o->file;
 526
 527         fputs(diff_line_prefix(o), file);
 528
 529         if (len == 0) {
 530                 has_trailing_newline = (first == '\n');
 531                 has_trailing_carriage_return = (!has_trailing_newline &&
 532                                                 (first == '\r'));
 533                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 534         } else {
 535                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 536                 if (has_trailing_newline)
 537                         len--;
 538                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 539                 if (has_trailing_carriage_return)
 540                         len--;
 541                 nofirst = 0;
 542         }
 543
 544         if (len || !nofirst) {
 545                 fputs(set, file);
 546                 if (!nofirst)
 547                         fputc(first, file);
 548                 fwrite(line, len, 1, file);
 549                 fputs(reset, file);
 550         }
 551         if (has_trailing_carriage_return)
 552                 fputc('\r', file);
 553         if (has_trailing_newline)
 554                 fputc('\n', file);
 555 }
 556
 557 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 558                       const char *line, int len)
 559 {
 560         emit_line_0(o, set, reset, line[0], line+1, len-1);
 561 }
 562
 563 enum diff_symbol {
 564         DIFF_SYMBOL_FILEPAIR_PLUS,
 565         DIFF_SYMBOL_FILEPAIR_MINUS,
 566         DIFF_SYMBOL_WORDS_PORCELAIN,
 567         DIFF_SYMBOL_WORDS,
 568         DIFF_SYMBOL_CONTEXT,
 569         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 570         DIFF_SYMBOL_PLUS,
 571         DIFF_SYMBOL_MINUS,
 572         DIFF_SYMBOL_NO_LF_EOF,
 573         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 574         DIFF_SYMBOL_CONTEXT_MARKER,
 575         DIFF_SYMBOL_SEPARATOR
 576 };
 577 /*
 578  * Flags for content lines:
 579  * 0..12 are whitespace rules
 580  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 581  * 16 is marking if the line is blank at EOF
 582  */
 583 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF (1<<16)
 584 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 585
 586 static void emit_line_ws_markup(struct diff_options *o,
 587                                 const char *set, const char *reset,
 588                                 const char *line, int len, char sign,
 589                                 unsigned ws_rule, int blank_at_eof)
 590 {
 591         const char *ws = NULL;
 592
 593         if (o->ws_error_highlight & ws_rule) {
 594                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
 595                 if (!*ws)
 596                         ws = NULL;
 597         }
 598
 599         if (!ws)
 600                 emit_line_0(o, set, reset, sign, line, len);
 601         else if (blank_at_eof)
 602                 /* Blank line at EOF - paint '+' as well */
 603                 emit_line_0(o, ws, reset, sign, line, len);
 604         else {
 605                 /* Emit just the prefix, then the rest. */
 606                 emit_line_0(o, set, reset, sign, "", 0);
 607                 ws_check_emit(line, len, ws_rule,
 608                               o->file, set, reset, ws);
 609         }
 610 }
 611
 612 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
 613                              const char *line, int len, unsigned flags)
 614 {
 615         static const char *nneof = " No newline at end of file\n";
 616         const char *context, *reset, *set, *meta;
 617         switch (s) {
 618         case DIFF_SYMBOL_NO_LF_EOF:
 619                 context = diff_get_color_opt(o, DIFF_CONTEXT);
 620                 reset = diff_get_color_opt(o, DIFF_RESET);
 621                 putc('\n', o->file);
 622                 emit_line_0(o, context, reset, '\\',
 623                             nneof, strlen(nneof));
 624                 break;
 625         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
 626                 emit_line(o, "", "", line, len);
 627                 break;
 628         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
 629         case DIFF_SYMBOL_CONTEXT_MARKER:
 630                 context = diff_get_color_opt(o, DIFF_CONTEXT);
 631                 reset = diff_get_color_opt(o, DIFF_RESET);
 632                 emit_line(o, context, reset, line, len);
 633                 break;
 634         case DIFF_SYMBOL_SEPARATOR:
 635                 fprintf(o->file, "%s%c",
 636                         diff_line_prefix(o),
 637                         o->line_termination);
 638                 break;
 639         case DIFF_SYMBOL_CONTEXT:
 640                 set = diff_get_color_opt(o, DIFF_CONTEXT);
 641                 reset = diff_get_color_opt(o, DIFF_RESET);
 642                 emit_line_ws_markup(o, set, reset, line, len, ' ',
 643                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
 644                 break;
 645         case DIFF_SYMBOL_PLUS:
 646                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
 647                 reset = diff_get_color_opt(o, DIFF_RESET);
 648                 emit_line_ws_markup(o, set, reset, line, len, '+',
 649                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
 650                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
 651                 break;
 652         case DIFF_SYMBOL_MINUS:
 653                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
 654                 reset = diff_get_color_opt(o, DIFF_RESET);
 655                 emit_line_ws_markup(o, set, reset, line, len, '-',
 656                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
 657                 break;
 658         case DIFF_SYMBOL_WORDS_PORCELAIN:
 659                 context = diff_get_color_opt(o, DIFF_CONTEXT);
 660                 reset = diff_get_color_opt(o, DIFF_RESET);
 661                 emit_line(o, context, reset, line, len);
 662                 fputs("~\n", o->file);
 663                 break;
 664         case DIFF_SYMBOL_WORDS:
 665                 context = diff_get_color_opt(o, DIFF_CONTEXT);
 666                 reset = diff_get_color_opt(o, DIFF_RESET);
 667                 /*
 668                  * Skip the prefix character, if any.  With
 669                  * diff_suppress_blank_empty, there may be
 670                  * none.
 671                  */
 672                 if (line[0] != '\n') {
 673                         line++;
 674                         len--;
 675                 }
 676                 emit_line(o, context, reset, line, len);
 677                 break;
 678         case DIFF_SYMBOL_FILEPAIR_PLUS:
 679                 meta = diff_get_color_opt(o, DIFF_METAINFO);
 680                 reset = diff_get_color_opt(o, DIFF_RESET);
 681                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
 682                         line, reset,
 683                         strchr(line, ' ') ? "\t" : "");
 684                 break;
 685         case DIFF_SYMBOL_FILEPAIR_MINUS:
 686                 meta = diff_get_color_opt(o, DIFF_METAINFO);
 687                 reset = diff_get_color_opt(o, DIFF_RESET);
 688                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
 689                         line, reset,
 690                         strchr(line, ' ') ? "\t" : "");
 691                 break;
 692         default:
 693                 die("BUG: unknown diff symbol");
 694         }
 695 }
 696
 697 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 698 {
 699         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 700               ecbdata->blank_at_eof_in_preimage &&
 701               ecbdata->blank_at_eof_in_postimage &&
 702               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 703               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 704                 return 0;
 705         return ws_blank_line(line, len, ecbdata->ws_rule);
 706 }
 707
 708 static void emit_add_line(const char *reset,
 709                           struct emit_callback *ecbdata,
 710                           const char *line, int len)
 711 {
 712         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
 713         if (new_blank_line_at_eof(ecbdata, line, len))
 714                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
 715
 716         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
 717 }
 718
 719 static void emit_del_line(const char *reset,
 720                           struct emit_callback *ecbdata,
 721                           const char *line, int len)
 722 {
 723         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
 724         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
 725 }
 726
 727 static void emit_context_line(const char *reset,
 728                               struct emit_callback *ecbdata,
 729                               const char *line, int len)
 730 {
 731         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
 732         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
 733 }
 734
 735 static void emit_hunk_header(struct emit_callback *ecbdata,
 736                              const char *line, int len)
 737 {
 738         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 739         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 740         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 741         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 742         static const char atat[2] = { '@', '@' };
 743         const char *cp, *ep;
 744         struct strbuf msgbuf = STRBUF_INIT;
 745         int org_len = len;
 746         int i = 1;
 747
 748         /*
 749          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 750          * it always is at least 10 bytes long.
 751          */
 752         if (len < 10 ||
 753             memcmp(line, atat, 2) ||
 754             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 755                 emit_diff_symbol(ecbdata->opt,
 756                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
 757                 return;
 758         }
 759         ep += 2; /* skip over @@ */
 760
 761         /* The hunk header in fraginfo color */
 762         strbuf_addstr(&msgbuf, frag);
 763         strbuf_add(&msgbuf, line, ep - line);
 764         strbuf_addstr(&msgbuf, reset);
 765
 766         /*
 767          * trailing "\r\n"
 768          */
 769         for ( ; i < 3; i++)
 770                 if (line[len - i] == '\r' || line[len - i] == '\n')
 771                         len--;
 772
 773         /* blank before the func header */
 774         for (cp = ep; ep - line < len; ep++)
 775                 if (*ep != ' ' && *ep != '\t')
 776                         break;
 777         if (ep != cp) {
 778                 strbuf_addstr(&msgbuf, context);
 779                 strbuf_add(&msgbuf, cp, ep - cp);
 780                 strbuf_addstr(&msgbuf, reset);
 781         }
 782
 783         if (ep < line + len) {
 784                 strbuf_addstr(&msgbuf, func);
 785                 strbuf_add(&msgbuf, ep, line + len - ep);
 786                 strbuf_addstr(&msgbuf, reset);
 787         }
 788
 789         strbuf_add(&msgbuf, line + len, org_len - len);
 790         strbuf_complete_line(&msgbuf);
 791         emit_diff_symbol(ecbdata->opt,
 792                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
 793         strbuf_release(&msgbuf);
 794 }
 795
 796 static struct diff_tempfile *claim_diff_tempfile(void) {
 797         int i;
 798         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 799                 if (!diff_temp[i].name)
 800                         return diff_temp + i;
 801         die("BUG: diff is failing to clean up its tempfiles");
 802 }
 803
 804 static void remove_tempfile(void)
 805 {
 806         int i;
 807         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 808                 if (is_tempfile_active(&diff_temp[i].tempfile))
 809                         delete_tempfile(&diff_temp[i].tempfile);
 810                 diff_temp[i].name = NULL;
 811         }
 812 }
 813
 814 static void print_line_count(FILE *file, int count)
 815 {
 816         switch (count) {
 817         case 0:
 818                 fprintf(file, "0,0");
 819                 break;
 820         case 1:
 821                 fprintf(file, "1");
 822                 break;
 823         default:
 824                 fprintf(file, "1,%d", count);
 825                 break;
 826         }
 827 }
 828
 829 static void emit_rewrite_lines(struct emit_callback *ecb,
 830                                int prefix, const char *data, int size)
 831 {
 832         const char *endp = NULL;
 833         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 834
 835         while (0 < size) {
 836                 int len;
 837
 838                 endp = memchr(data, '\n', size);
 839                 len = endp ? (endp - data + 1) : size;
 840                 if (prefix != '+') {
 841                         ecb->lno_in_preimage++;
 842                         emit_del_line(reset, ecb, data, len);
 843                 } else {
 844                         ecb->lno_in_postimage++;
 845                         emit_add_line(reset, ecb, data, len);
 846                 }
 847                 size -= len;
 848                 data += len;
 849         }
 850         if (!endp)
 851                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
 852 }
 853
 854 static void emit_rewrite_diff(const char *name_a,
 855                               const char *name_b,
 856                               struct diff_filespec *one,
 857                               struct diff_filespec *two,
 858                               struct userdiff_driver *textconv_one,
 859                               struct userdiff_driver *textconv_two,
 860                               struct diff_options *o)
 861 {
 862         int lc_a, lc_b;
 863         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 864         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 865         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 866         const char *a_prefix, *b_prefix;
 867         char *data_one, *data_two;
 868         size_t size_one, size_two;
 869         struct emit_callback ecbdata;
 870         const char *line_prefix = diff_line_prefix(o);
 871
 872         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 873                 a_prefix = o->b_prefix;
 874                 b_prefix = o->a_prefix;
 875         } else {
 876                 a_prefix = o->a_prefix;
 877                 b_prefix = o->b_prefix;
 878         }
 879
 880         name_a += (*name_a == '/');
 881         name_b += (*name_b == '/');
 882
 883         strbuf_reset(&a_name);
 884         strbuf_reset(&b_name);
 885         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 886         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 887
 888         size_one = fill_textconv(textconv_one, one, &data_one);
 889         size_two = fill_textconv(textconv_two, two, &data_two);
 890
 891         memset(&ecbdata, 0, sizeof(ecbdata));
 892         ecbdata.color_diff = want_color(o->use_color);
 893         ecbdata.ws_rule = whitespace_rule(name_b);
 894         ecbdata.opt = o;
 895         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 896                 mmfile_t mf1, mf2;
 897                 mf1.ptr = (char *)data_one;
 898                 mf2.ptr = (char *)data_two;
 899                 mf1.size = size_one;
 900                 mf2.size = size_two;
 901                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 902         }
 903         ecbdata.lno_in_preimage = 1;
 904         ecbdata.lno_in_postimage = 1;
 905
 906         lc_a = count_lines(data_one, size_one);
 907         lc_b = count_lines(data_two, size_two);
 908
 909         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
 910                          a_name.buf, a_name.len, 0);
 911         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
 912                          b_name.buf, b_name.len, 0);
 913
 914         fprintf(o->file, "%s%s@@ -", line_prefix, fraginfo);
 915         if (!o->irreversible_delete)
 916                 print_line_count(o->file, lc_a);
 917         else
 918                 fprintf(o->file, "?,?");
 919         fprintf(o->file, " +");
 920         print_line_count(o->file, lc_b);
 921         fprintf(o->file, " @@%s\n", reset);
 922         if (lc_a && !o->irreversible_delete)
 923                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 924         if (lc_b)
 925                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 926         if (textconv_one)
 927                 free((char *)data_one);
 928         if (textconv_two)
 929                 free((char *)data_two);
 930 }
 931
 932 struct diff_words_buffer {
 933         mmfile_t text;
 934         long alloc;
 935         struct diff_words_orig {
 936                 const char *begin, *end;
 937         } *orig;
 938         int orig_nr, orig_alloc;
 939 };
 940
 941 static void diff_words_append(char *line, unsigned long len,
 942                 struct diff_words_buffer *buffer)
 943 {
 944         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 945         line++;
 946         len--;
 947         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 948         buffer->text.size += len;
 949         buffer->text.ptr[buffer->text.size] = '\0';
 950 }
 951
 952 struct diff_words_style_elem {
 953         const char *prefix;
 954         const char *suffix;
 955         const char *color; /* NULL; filled in by the setup code if
 956                             * color is enabled */
 957 };
 958
 959 struct diff_words_style {
 960         enum diff_words_type type;
 961         struct diff_words_style_elem new, old, ctx;
 962         const char *newline;
 963 };
 964
 965 static struct diff_words_style diff_words_styles[] = {
 966         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 967         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 968         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 969 };
 970
 971 struct diff_words_data {
 972         struct diff_words_buffer minus, plus;
 973         const char *current_plus;
 974         int last_minus;
 975         struct diff_options *opt;
 976         regex_t *word_regex;
 977         enum diff_words_type type;
 978         struct diff_words_style *style;
 979 };
 980
 981 static int fn_out_diff_words_write_helper(FILE *fp,
 982                                           struct diff_words_style_elem *st_el,
 983                                           const char *newline,
 984                                           size_t count, const char *buf,
 985                                           const char *line_prefix)
 986 {
 987         int print = 0;
 988
 989         while (count) {
 990                 char *p = memchr(buf, '\n', count);
 991                 if (print)
 992                         fputs(line_prefix, fp);
 993                 if (p != buf) {
 994                         if (st_el->color && fputs(st_el->color, fp) < 0)
 995                                 return -1;
 996                         if (fputs(st_el->prefix, fp) < 0 ||
 997                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 998                             fputs(st_el->suffix, fp) < 0)
 999                                 return -1;
1000                         if (st_el->color && *st_el->color
1001                             && fputs(GIT_COLOR_RESET, fp) < 0)
1002                                 return -1;
1003                 }
1004                 if (!p)
1005                         return 0;
1006                 if (fputs(newline, fp) < 0)
1007                         return -1;
1008                 count -= p + 1 - buf;
1009                 buf = p + 1;
1010                 print = 1;
1011         }
1012         return 0;
1013 }
1014
1015 /*
1016  * '--color-words' algorithm can be described as:
1017  *
1018  *   1. collect the minus/plus lines of a diff hunk, divided into
1019  *      minus-lines and plus-lines;
1020  *
1021  *   2. break both minus-lines and plus-lines into words and
1022  *      place them into two mmfile_t with one word for each line;
1023  *
1024  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1025  *
1026  * And for the common parts of the both file, we output the plus side text.
1027  * diff_words->current_plus is used to trace the current position of the plus file
1028  * which printed. diff_words->last_minus is used to trace the last minus word
1029  * printed.
1030  *
1031  * For '--graph' to work with '--color-words', we need to output the graph prefix
1032  * on each line of color words output. Generally, there are two conditions on
1033  * which we should output the prefix.
1034  *
1035  *   1. diff_words->last_minus == 0 &&
1036  *      diff_words->current_plus == diff_words->plus.text.ptr
1037  *
1038  *      that is: the plus text must start as a new line, and if there is no minus
1039  *      word printed, a graph prefix must be printed.
1040  *
1041  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1042  *      *(diff_words->current_plus - 1) == '\n'
1043  *
1044  *      that is: a graph prefix must be printed following a '\n'
1045  */
1046 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1047 {
1048         if ((diff_words->last_minus == 0 &&
1049                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1050                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1051                 *(diff_words->current_plus - 1) == '\n')) {
1052                 return 1;
1053         } else {
1054                 return 0;
1055         }
1056 }
1057
1058 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1059 {
1060         struct diff_words_data *diff_words = priv;
1061         struct diff_words_style *style = diff_words->style;
1062         int minus_first, minus_len, plus_first, plus_len;
1063         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1064         struct diff_options *opt = diff_words->opt;
1065         const char *line_prefix;
1066
1067         if (line[0] != '@' || parse_hunk_header(line, len,
1068                         &minus_first, &minus_len, &plus_first, &plus_len))
1069                 return;
1070
1071         assert(opt);
1072         line_prefix = diff_line_prefix(opt);
1073
1074         /* POSIX requires that first be decremented by one if len == 0... */
1075         if (minus_len) {
1076                 minus_begin = diff_words->minus.orig[minus_first].begin;
1077                 minus_end =
1078                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1079         } else
1080                 minus_begin = minus_end =
1081                         diff_words->minus.orig[minus_first].end;
1082
1083         if (plus_len) {
1084                 plus_begin = diff_words->plus.orig[plus_first].begin;
1085                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1086         } else
1087                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1088
1089         if (color_words_output_graph_prefix(diff_words)) {
1090                 fputs(line_prefix, diff_words->opt->file);
1091         }
1092         if (diff_words->current_plus != plus_begin) {
1093                 fn_out_diff_words_write_helper(diff_words->opt->file,
1094                                 &style->ctx, style->newline,
1095                                 plus_begin - diff_words->current_plus,
1096                                 diff_words->current_plus, line_prefix);
1097                 if (*(plus_begin - 1) == '\n')
1098                         fputs(line_prefix, diff_words->opt->file);
1099         }
1100         if (minus_begin != minus_end) {
1101                 fn_out_diff_words_write_helper(diff_words->opt->file,
1102                                 &style->old, style->newline,
1103                                 minus_end - minus_begin, minus_begin,
1104                                 line_prefix);
1105         }
1106         if (plus_begin != plus_end) {
1107                 fn_out_diff_words_write_helper(diff_words->opt->file,
1108                                 &style->new, style->newline,
1109                                 plus_end - plus_begin, plus_begin,
1110                                 line_prefix);
1111         }
1112
1113         diff_words->current_plus = plus_end;
1114         diff_words->last_minus = minus_first;
1115 }
1116
1117 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1118 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1119                 int *begin, int *end)
1120 {
1121         if (word_regex && *begin < buffer->size) {
1122                 regmatch_t match[1];
1123                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1124                                  buffer->size - *begin, 1, match, 0)) {
1125                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1126                                         '\n', match[0].rm_eo - match[0].rm_so);
1127                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1128                         *begin += match[0].rm_so;
1129                         return *begin >= *end;
1130                 }
1131                 return -1;
1132         }
1133
1134         /* find the next word */
1135         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1136                 (*begin)++;
1137         if (*begin >= buffer->size)
1138                 return -1;
1139
1140         /* find the end of the word */
1141         *end = *begin + 1;
1142         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1143                 (*end)++;
1144
1145         return 0;
1146 }
1147
1148 /*
1149  * This function splits the words in buffer->text, stores the list with
1150  * newline separator into out, and saves the offsets of the original words
1151  * in buffer->orig.
1152  */
1153 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1154                 regex_t *word_regex)
1155 {
1156         int i, j;
1157         long alloc = 0;
1158
1159         out->size = 0;
1160         out->ptr = NULL;
1161
1162         /* fake an empty "0th" word */
1163         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1164         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1165         buffer->orig_nr = 1;
1166
1167         for (i = 0; i < buffer->text.size; i++) {
1168                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1169                         return;
1170
1171                 /* store original boundaries */
1172                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1173                                 buffer->orig_alloc);
1174                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1175                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1176                 buffer->orig_nr++;
1177
1178                 /* store one word */
1179                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1180                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1181                 out->ptr[out->size + j - i] = '\n';
1182                 out->size += j - i + 1;
1183
1184                 i = j - 1;
1185         }
1186 }
1187
1188 /* this executes the word diff on the accumulated buffers */
1189 static void diff_words_show(struct diff_words_data *diff_words)
1190 {
1191         xpparam_t xpp;
1192         xdemitconf_t xecfg;
1193         mmfile_t minus, plus;
1194         struct diff_words_style *style = diff_words->style;
1195
1196         struct diff_options *opt = diff_words->opt;
1197         const char *line_prefix;
1198
1199         assert(opt);
1200         line_prefix = diff_line_prefix(opt);
1201
1202         /* special case: only removal */
1203         if (!diff_words->plus.text.size) {
1204                 fputs(line_prefix, diff_words->opt->file);
1205                 fn_out_diff_words_write_helper(diff_words->opt->file,
1206                         &style->old, style->newline,
1207                         diff_words->minus.text.size,
1208                         diff_words->minus.text.ptr, line_prefix);
1209                 diff_words->minus.text.size = 0;
1210                 return;
1211         }
1212
1213         diff_words->current_plus = diff_words->plus.text.ptr;
1214         diff_words->last_minus = 0;
1215
1216         memset(&xpp, 0, sizeof(xpp));
1217         memset(&xecfg, 0, sizeof(xecfg));
1218         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1219         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1220         xpp.flags = 0;
1221         /* as only the hunk header will be parsed, we need a 0-context */
1222         xecfg.ctxlen = 0;
1223         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1224                           &xpp, &xecfg))
1225                 die("unable to generate word diff");
1226         free(minus.ptr);
1227         free(plus.ptr);
1228         if (diff_words->current_plus != diff_words->plus.text.ptr +
1229                         diff_words->plus.text.size) {
1230                 if (color_words_output_graph_prefix(diff_words))
1231                         fputs(line_prefix, diff_words->opt->file);
1232                 fn_out_diff_words_write_helper(diff_words->opt->file,
1233                         &style->ctx, style->newline,
1234                         diff_words->plus.text.ptr + diff_words->plus.text.size
1235                         - diff_words->current_plus, diff_words->current_plus,
1236                         line_prefix);
1237         }
1238         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1239 }
1240
1241 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1242 static void diff_words_flush(struct emit_callback *ecbdata)
1243 {
1244         if (ecbdata->diff_words->minus.text.size ||
1245             ecbdata->diff_words->plus.text.size)
1246                 diff_words_show(ecbdata->diff_words);
1247 }
1248
1249 static void diff_filespec_load_driver(struct diff_filespec *one)
1250 {
1251         /* Use already-loaded driver */
1252         if (one->driver)
1253                 return;
1254
1255         if (S_ISREG(one->mode))
1256                 one->driver = userdiff_find_by_path(one->path);
1257
1258         /* Fallback to default settings */
1259         if (!one->driver)
1260                 one->driver = userdiff_find_by_name("default");
1261 }
1262
1263 static const char *userdiff_word_regex(struct diff_filespec *one)
1264 {
1265         diff_filespec_load_driver(one);
1266         return one->driver->word_regex;
1267 }
1268
1269 static void init_diff_words_data(struct emit_callback *ecbdata,
1270                                  struct diff_options *orig_opts,
1271                                  struct diff_filespec *one,
1272                                  struct diff_filespec *two)
1273 {
1274         int i;
1275         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1276         memcpy(o, orig_opts, sizeof(struct diff_options));
1277
1278         ecbdata->diff_words =
1279                 xcalloc(1, sizeof(struct diff_words_data));
1280         ecbdata->diff_words->type = o->word_diff;
1281         ecbdata->diff_words->opt = o;
1282         if (!o->word_regex)
1283                 o->word_regex = userdiff_word_regex(one);
1284         if (!o->word_regex)
1285                 o->word_regex = userdiff_word_regex(two);
1286         if (!o->word_regex)
1287                 o->word_regex = diff_word_regex_cfg;
1288         if (o->word_regex) {
1289                 ecbdata->diff_words->word_regex = (regex_t *)
1290                         xmalloc(sizeof(regex_t));
1291                 if (regcomp(ecbdata->diff_words->word_regex,
1292                             o->word_regex,
1293                             REG_EXTENDED | REG_NEWLINE))
1294                         die ("Invalid regular expression: %s",
1295                              o->word_regex);
1296         }
1297         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1298                 if (o->word_diff == diff_words_styles[i].type) {
1299                         ecbdata->diff_words->style =
1300                                 &diff_words_styles[i];
1301                         break;
1302                 }
1303         }
1304         if (want_color(o->use_color)) {
1305                 struct diff_words_style *st = ecbdata->diff_words->style;
1306                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1307                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1308                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1309         }
1310 }
1311
1312 static void free_diff_words_data(struct emit_callback *ecbdata)
1313 {
1314         if (ecbdata->diff_words) {
1315                 diff_words_flush(ecbdata);
1316                 free (ecbdata->diff_words->opt);
1317                 free (ecbdata->diff_words->minus.text.ptr);
1318                 free (ecbdata->diff_words->minus.orig);
1319                 free (ecbdata->diff_words->plus.text.ptr);
1320                 free (ecbdata->diff_words->plus.orig);
1321                 if (ecbdata->diff_words->word_regex) {
1322                         regfree(ecbdata->diff_words->word_regex);
1323                         free(ecbdata->diff_words->word_regex);
1324                 }
1325                 FREE_AND_NULL(ecbdata->diff_words);
1326         }
1327 }
1328
1329 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1330 {
1331         if (want_color(diff_use_color))
1332                 return diff_colors[ix];
1333         return "";
1334 }
1335
1336 const char *diff_line_prefix(struct diff_options *opt)
1337 {
1338         struct strbuf *msgbuf;
1339         if (!opt->output_prefix)
1340                 return "";
1341
1342         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1343         return msgbuf->buf;
1344 }
1345
1346 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1347 {
1348         const char *cp;
1349         unsigned long allot;
1350         size_t l = len;
1351
1352         if (ecb->truncate)
1353                 return ecb->truncate(line, len);
1354         cp = line;
1355         allot = l;
1356         while (0 < l) {
1357                 (void) utf8_width(&cp, &l);
1358                 if (!cp)
1359                         break; /* truncated in the middle? */
1360         }
1361         return allot - l;
1362 }
1363
1364 static void find_lno(const char *line, struct emit_callback *ecbdata)
1365 {
1366         const char *p;
1367         ecbdata->lno_in_preimage = 0;
1368         ecbdata->lno_in_postimage = 0;
1369         p = strchr(line, '-');
1370         if (!p)
1371                 return; /* cannot happen */
1372         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1373         p = strchr(p, '+');
1374         if (!p)
1375                 return; /* cannot happen */
1376         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1377 }
1378
1379 static void fn_out_consume(void *priv, char *line, unsigned long len)
1380 {
1381         struct emit_callback *ecbdata = priv;
1382         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1383         struct diff_options *o = ecbdata->opt;
1384
1385         o->found_changes = 1;
1386
1387         if (ecbdata->header) {
1388                 fprintf(o->file, "%s", ecbdata->header->buf);
1389                 strbuf_reset(ecbdata->header);
1390                 ecbdata->header = NULL;
1391         }
1392
1393         if (ecbdata->label_path[0]) {
1394                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1395                                  ecbdata->label_path[0],
1396                                  strlen(ecbdata->label_path[0]), 0);
1397                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1398                                  ecbdata->label_path[1],
1399                                  strlen(ecbdata->label_path[1]), 0);
1400                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1401         }
1402
1403         if (diff_suppress_blank_empty
1404             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1405                 line[0] = '\n';
1406                 len = 1;
1407         }
1408
1409         if (line[0] == '@') {
1410                 if (ecbdata->diff_words)
1411                         diff_words_flush(ecbdata);
1412                 len = sane_truncate_line(ecbdata, line, len);
1413                 find_lno(line, ecbdata);
1414                 emit_hunk_header(ecbdata, line, len);
1415                 return;
1416         }
1417
1418         if (ecbdata->diff_words) {
1419                 enum diff_symbol s =
1420                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
1421                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
1422                 if (line[0] == '-') {
1423                         diff_words_append(line, len,
1424                                           &ecbdata->diff_words->minus);
1425                         return;
1426                 } else if (line[0] == '+') {
1427                         diff_words_append(line, len,
1428                                           &ecbdata->diff_words->plus);
1429                         return;
1430                 } else if (starts_with(line, "\\ ")) {
1431                         /*
1432                          * Eat the "no newline at eof" marker as if we
1433                          * saw a "+" or "-" line with nothing on it,
1434                          * and return without diff_words_flush() to
1435                          * defer processing. If this is the end of
1436                          * preimage, more "+" lines may come after it.
1437                          */
1438                         return;
1439                 }
1440                 diff_words_flush(ecbdata);
1441                 emit_diff_symbol(o, s, line, len, 0);
1442                 return;
1443         }
1444
1445         switch (line[0]) {
1446         case '+':
1447                 ecbdata->lno_in_postimage++;
1448                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1449                 break;
1450         case '-':
1451                 ecbdata->lno_in_preimage++;
1452                 emit_del_line(reset, ecbdata, line + 1, len - 1);
1453                 break;
1454         case ' ':
1455                 ecbdata->lno_in_postimage++;
1456                 ecbdata->lno_in_preimage++;
1457                 emit_context_line(reset, ecbdata, line + 1, len - 1);
1458                 break;
1459         default:
1460                 /* incomplete line at the end */
1461                 ecbdata->lno_in_preimage++;
1462                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
1463                                  line, len, 0);
1464                 break;
1465         }
1466 }
1467
1468 static char *pprint_rename(const char *a, const char *b)
1469 {
1470         const char *old = a;
1471         const char *new = b;
1472         struct strbuf name = STRBUF_INIT;
1473         int pfx_length, sfx_length;
1474         int pfx_adjust_for_slash;
1475         int len_a = strlen(a);
1476         int len_b = strlen(b);
1477         int a_midlen, b_midlen;
1478         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1479         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1480
1481         if (qlen_a || qlen_b) {
1482                 quote_c_style(a, &name, NULL, 0);
1483                 strbuf_addstr(&name, " => ");
1484                 quote_c_style(b, &name, NULL, 0);
1485                 return strbuf_detach(&name, NULL);
1486         }
1487
1488         /* Find common prefix */
1489         pfx_length = 0;
1490         while (*old && *new && *old == *new) {
1491                 if (*old == '/')
1492                         pfx_length = old - a + 1;
1493                 old++;
1494                 new++;
1495         }
1496
1497         /* Find common suffix */
1498         old = a + len_a;
1499         new = b + len_b;
1500         sfx_length = 0;
1501         /*
1502          * If there is a common prefix, it must end in a slash.  In
1503          * that case we let this loop run 1 into the prefix to see the
1504          * same slash.
1505          *
1506          * If there is no common prefix, we cannot do this as it would
1507          * underrun the input strings.
1508          */
1509         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1510         while (a + pfx_length - pfx_adjust_for_slash <= old &&
1511                b + pfx_length - pfx_adjust_for_slash <= new &&
1512                *old == *new) {
1513                 if (*old == '/')
1514                         sfx_length = len_a - (old - a);
1515                 old--;
1516                 new--;
1517         }
1518
1519         /*
1520          * pfx{mid-a => mid-b}sfx
1521          * {pfx-a => pfx-b}sfx
1522          * pfx{sfx-a => sfx-b}
1523          * name-a => name-b
1524          */
1525         a_midlen = len_a - pfx_length - sfx_length;
1526         b_midlen = len_b - pfx_length - sfx_length;
1527         if (a_midlen < 0)
1528                 a_midlen = 0;
1529         if (b_midlen < 0)
1530                 b_midlen = 0;
1531
1532         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1533         if (pfx_length + sfx_length) {
1534                 strbuf_add(&name, a, pfx_length);
1535                 strbuf_addch(&name, '{');
1536         }
1537         strbuf_add(&name, a + pfx_length, a_midlen);
1538         strbuf_addstr(&name, " => ");
1539         strbuf_add(&name, b + pfx_length, b_midlen);
1540         if (pfx_length + sfx_length) {
1541                 strbuf_addch(&name, '}');
1542                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1543         }
1544         return strbuf_detach(&name, NULL);
1545 }
1546
1547 struct diffstat_t {
1548         int nr;
1549         int alloc;
1550         struct diffstat_file {
1551                 char *from_name;
1552                 char *name;
1553                 char *print_name;
1554                 unsigned is_unmerged:1;
1555                 unsigned is_binary:1;
1556                 unsigned is_renamed:1;
1557                 unsigned is_interesting:1;
1558                 uintmax_t added, deleted;
1559         } **files;
1560 };
1561
1562 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1563                                           const char *name_a,
1564                                           const char *name_b)
1565 {
1566         struct diffstat_file *x;
1567         x = xcalloc(1, sizeof(*x));
1568         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1569         diffstat->files[diffstat->nr++] = x;
1570         if (name_b) {
1571                 x->from_name = xstrdup(name_a);
1572                 x->name = xstrdup(name_b);
1573                 x->is_renamed = 1;
1574         }
1575         else {
1576                 x->from_name = NULL;
1577                 x->name = xstrdup(name_a);
1578         }
1579         return x;
1580 }
1581
1582 static void diffstat_consume(void *priv, char *line, unsigned long len)
1583 {
1584         struct diffstat_t *diffstat = priv;
1585         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1586
1587         if (line[0] == '+')
1588                 x->added++;
1589         else if (line[0] == '-')
1590                 x->deleted++;
1591 }
1592
1593 const char mime_boundary_leader[] = "------------";
1594
1595 static int scale_linear(int it, int width, int max_change)
1596 {
1597         if (!it)
1598                 return 0;
1599         /*
1600          * make sure that at least one '-' or '+' is printed if
1601          * there is any change to this path. The easiest way is to
1602          * scale linearly as if the alloted width is one column shorter
1603          * than it is, and then add 1 to the result.
1604          */
1605         return 1 + (it * (width - 1) / max_change);
1606 }
1607
1608 static void show_name(FILE *file,
1609                       const char *prefix, const char *name, int len)
1610 {
1611         fprintf(file, " %s%-*s |", prefix, len, name);
1612 }
1613
1614 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1615 {
1616         if (cnt <= 0)
1617                 return;
1618         fprintf(file, "%s", set);
1619         while (cnt--)
1620                 putc(ch, file);
1621         fprintf(file, "%s", reset);
1622 }
1623
1624 static void fill_print_name(struct diffstat_file *file)
1625 {
1626         char *pname;
1627
1628         if (file->print_name)
1629                 return;
1630
1631         if (!file->is_renamed) {
1632                 struct strbuf buf = STRBUF_INIT;
1633                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1634                         pname = strbuf_detach(&buf, NULL);
1635                 } else {
1636                         pname = file->name;
1637                         strbuf_release(&buf);
1638                 }
1639         } else {
1640                 pname = pprint_rename(file->from_name, file->name);
1641         }
1642         file->print_name = pname;
1643 }
1644
1645 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1646 {
1647         struct strbuf sb = STRBUF_INIT;
1648         int ret;
1649
1650         if (!files) {
1651                 assert(insertions == 0 && deletions == 0);
1652                 return fprintf(fp, "%s\n", " 0 files changed");
1653         }
1654
1655         strbuf_addf(&sb,
1656                     (files == 1) ? " %d file changed" : " %d files changed",
1657                     files);
1658
1659         /*
1660          * For binary diff, the caller may want to print "x files
1661          * changed" with insertions == 0 && deletions == 0.
1662          *
1663          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1664          * is probably less confusing (i.e skip over "2 files changed
1665          * but nothing about added/removed lines? Is this a bug in Git?").
1666          */
1667         if (insertions || deletions == 0) {
1668                 strbuf_addf(&sb,
1669                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1670                             insertions);
1671         }
1672
1673         if (deletions || insertions == 0) {
1674                 strbuf_addf(&sb,
1675                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1676                             deletions);
1677         }
1678         strbuf_addch(&sb, '\n');
1679         ret = fputs(sb.buf, fp);
1680         strbuf_release(&sb);
1681         return ret;
1682 }
1683
1684 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1685 {
1686         int i, len, add, del, adds = 0, dels = 0;
1687         uintmax_t max_change = 0, max_len = 0;
1688         int total_files = data->nr, count;
1689         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1690         const char *reset, *add_c, *del_c;
1691         const char *line_prefix = "";
1692         int extra_shown = 0;
1693
1694         if (data->nr == 0)
1695                 return;
1696
1697         line_prefix = diff_line_prefix(options);
1698         count = options->stat_count ? options->stat_count : data->nr;
1699
1700         reset = diff_get_color_opt(options, DIFF_RESET);
1701         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1702         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1703
1704         /*
1705          * Find the longest filename and max number of changes
1706          */
1707         for (i = 0; (i < count) && (i < data->nr); i++) {
1708                 struct diffstat_file *file = data->files[i];
1709                 uintmax_t change = file->added + file->deleted;
1710
1711                 if (!file->is_interesting && (change == 0)) {
1712                         count++; /* not shown == room for one more */
1713                         continue;
1714                 }
1715                 fill_print_name(file);
1716                 len = strlen(file->print_name);
1717                 if (max_len < len)
1718                         max_len = len;
1719
1720                 if (file->is_unmerged) {
1721                         /* "Unmerged" is 8 characters */
1722                         bin_width = bin_width < 8 ? 8 : bin_width;
1723                         continue;
1724                 }
1725                 if (file->is_binary) {
1726                         /* "Bin XXX -> YYY bytes" */
1727                         int w = 14 + decimal_width(file->added)
1728                                 + decimal_width(file->deleted);
1729                         bin_width = bin_width < w ? w : bin_width;
1730                         /* Display change counts aligned with "Bin" */
1731                         number_width = 3;
1732                         continue;
1733                 }
1734
1735                 if (max_change < change)
1736                         max_change = change;
1737         }
1738         count = i; /* where we can stop scanning in data->files[] */
1739
1740         /*
1741          * We have width = stat_width or term_columns() columns total.
1742          * We want a maximum of min(max_len, stat_name_width) for the name part.
1743          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1744          * We also need 1 for " " and 4 + decimal_width(max_change)
1745          * for " | NNNN " and one the empty column at the end, altogether
1746          * 6 + decimal_width(max_change).
1747          *
1748          * If there's not enough space, we will use the smaller of
1749          * stat_name_width (if set) and 5/8*width for the filename,
1750          * and the rest for constant elements + graph part, but no more
1751          * than stat_graph_width for the graph part.
1752          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1753          * for the standard terminal size).
1754          *
1755          * In other words: stat_width limits the maximum width, and
1756          * stat_name_width fixes the maximum width of the filename,
1757          * and is also used to divide available columns if there
1758          * aren't enough.
1759          *
1760          * Binary files are displayed with "Bin XXX -> YYY bytes"
1761          * instead of the change count and graph. This part is treated
1762          * similarly to the graph part, except that it is not
1763          * "scaled". If total width is too small to accommodate the
1764          * guaranteed minimum width of the filename part and the
1765          * separators and this message, this message will "overflow"
1766          * making the line longer than the maximum width.
1767          */
1768
1769         if (options->stat_width == -1)
1770                 width = term_columns() - strlen(line_prefix);
1771         else
1772                 width = options->stat_width ? options->stat_width : 80;
1773         number_width = decimal_width(max_change) > number_width ?
1774                 decimal_width(max_change) : number_width;
1775
1776         if (options->stat_graph_width == -1)
1777                 options->stat_graph_width = diff_stat_graph_width;
1778
1779         /*
1780          * Guarantee 3/8*16==6 for the graph part
1781          * and 5/8*16==10 for the filename part
1782          */
1783         if (width < 16 + 6 + number_width)
1784                 width = 16 + 6 + number_width;
1785
1786         /*
1787          * First assign sizes that are wanted, ignoring available width.
1788          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1789          * starting from "XXX" should fit in graph_width.
1790          */
1791         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1792         if (options->stat_graph_width &&
1793             options->stat_graph_width < graph_width)
1794                 graph_width = options->stat_graph_width;
1795
1796         name_width = (options->stat_name_width > 0 &&
1797                       options->stat_name_width < max_len) ?
1798                 options->stat_name_width : max_len;
1799
1800         /*
1801          * Adjust adjustable widths not to exceed maximum width
1802          */
1803         if (name_width + number_width + 6 + graph_width > width) {
1804                 if (graph_width > width * 3/8 - number_width - 6) {
1805                         graph_width = width * 3/8 - number_width - 6;
1806                         if (graph_width < 6)
1807                                 graph_width = 6;
1808                 }
1809
1810                 if (options->stat_graph_width &&
1811                     graph_width > options->stat_graph_width)
1812                         graph_width = options->stat_graph_width;
1813                 if (name_width > width - number_width - 6 - graph_width)
1814                         name_width = width - number_width - 6 - graph_width;
1815                 else
1816                         graph_width = width - number_width - 6 - name_width;
1817         }
1818
1819         /*
1820          * From here name_width is the width of the name area,
1821          * and graph_width is the width of the graph area.
1822          * max_change is used to scale graph properly.
1823          */
1824         for (i = 0; i < count; i++) {
1825                 const char *prefix = "";
1826                 struct diffstat_file *file = data->files[i];
1827                 char *name = file->print_name;
1828                 uintmax_t added = file->added;
1829                 uintmax_t deleted = file->deleted;
1830                 int name_len;
1831
1832                 if (!file->is_interesting && (added + deleted == 0))
1833                         continue;
1834
1835                 /*
1836                  * "scale" the filename
1837                  */
1838                 len = name_width;
1839                 name_len = strlen(name);
1840                 if (name_width < name_len) {
1841                         char *slash;
1842                         prefix = "...";
1843                         len -= 3;
1844                         name += name_len - len;
1845                         slash = strchr(name, '/');
1846                         if (slash)
1847                                 name = slash;
1848                 }
1849
1850                 if (file->is_binary) {
1851                         fprintf(options->file, "%s", line_prefix);
1852                         show_name(options->file, prefix, name, len);
1853                         fprintf(options->file, " %*s", number_width, "Bin");
1854                         if (!added && !deleted) {
1855                                 putc('\n', options->file);
1856                                 continue;
1857                         }
1858                         fprintf(options->file, " %s%"PRIuMAX"%s",
1859                                 del_c, deleted, reset);
1860                         fprintf(options->file, " -> ");
1861                         fprintf(options->file, "%s%"PRIuMAX"%s",
1862                                 add_c, added, reset);
1863                         fprintf(options->file, " bytes");
1864                         fprintf(options->file, "\n");
1865                         continue;
1866                 }
1867                 else if (file->is_unmerged) {
1868                         fprintf(options->file, "%s", line_prefix);
1869                         show_name(options->file, prefix, name, len);
1870                         fprintf(options->file, " Unmerged\n");
1871                         continue;
1872                 }
1873
1874                 /*
1875                  * scale the add/delete
1876                  */
1877                 add = added;
1878                 del = deleted;
1879
1880                 if (graph_width <= max_change) {
1881                         int total = scale_linear(add + del, graph_width, max_change);
1882                         if (total < 2 && add && del)
1883                                 /* width >= 2 due to the sanity check */
1884                                 total = 2;
1885                         if (add < del) {
1886                                 add = scale_linear(add, graph_width, max_change);
1887                                 del = total - add;
1888                         } else {
1889                                 del = scale_linear(del, graph_width, max_change);
1890                                 add = total - del;
1891                         }
1892                 }
1893                 fprintf(options->file, "%s", line_prefix);
1894                 show_name(options->file, prefix, name, len);
1895                 fprintf(options->file, " %*"PRIuMAX"%s",
1896                         number_width, added + deleted,
1897                         added + deleted ? " " : "");
1898                 show_graph(options->file, '+', add, add_c, reset);
1899                 show_graph(options->file, '-', del, del_c, reset);
1900                 fprintf(options->file, "\n");
1901         }
1902
1903         for (i = 0; i < data->nr; i++) {
1904                 struct diffstat_file *file = data->files[i];
1905                 uintmax_t added = file->added;
1906                 uintmax_t deleted = file->deleted;
1907
1908                 if (file->is_unmerged ||
1909                     (!file->is_interesting && (added + deleted == 0))) {
1910                         total_files--;
1911                         continue;
1912                 }
1913
1914                 if (!file->is_binary) {
1915                         adds += added;
1916                         dels += deleted;
1917                 }
1918                 if (i < count)
1919                         continue;
1920                 if (!extra_shown)
1921                         fprintf(options->file, "%s ...\n", line_prefix);
1922                 extra_shown = 1;
1923         }
1924         fprintf(options->file, "%s", line_prefix);
1925         print_stat_summary(options->file, total_files, adds, dels);
1926 }
1927
1928 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1929 {
1930         int i, adds = 0, dels = 0, total_files = data->nr;
1931
1932         if (data->nr == 0)
1933                 return;
1934
1935         for (i = 0; i < data->nr; i++) {
1936                 int added = data->files[i]->added;
1937                 int deleted= data->files[i]->deleted;
1938
1939                 if (data->files[i]->is_unmerged ||
1940                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1941                         total_files--;
1942                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1943                         adds += added;
1944                         dels += deleted;
1945                 }
1946         }
1947         fprintf(options->file, "%s", diff_line_prefix(options));
1948         print_stat_summary(options->file, total_files, adds, dels);
1949 }
1950
1951 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1952 {
1953         int i;
1954
1955         if (data->nr == 0)
1956                 return;
1957
1958         for (i = 0; i < data->nr; i++) {
1959                 struct diffstat_file *file = data->files[i];
1960
1961                 fprintf(options->file, "%s", diff_line_prefix(options));
1962
1963                 if (file->is_binary)
1964                         fprintf(options->file, "-\t-\t");
1965                 else
1966                         fprintf(options->file,
1967                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1968                                 file->added, file->deleted);
1969                 if (options->line_termination) {
1970                         fill_print_name(file);
1971                         if (!file->is_renamed)
1972                                 write_name_quoted(file->name, options->file,
1973                                                   options->line_termination);
1974                         else {
1975                                 fputs(file->print_name, options->file);
1976                                 putc(options->line_termination, options->file);
1977                         }
1978                 } else {
1979                         if (file->is_renamed) {
1980                                 putc('\0', options->file);
1981                                 write_name_quoted(file->from_name, options->file, '\0');
1982                         }
1983                         write_name_quoted(file->name, options->file, '\0');
1984                 }
1985         }
1986 }
1987
1988 struct dirstat_file {
1989         const char *name;
1990         unsigned long changed;
1991 };
1992
1993 struct dirstat_dir {
1994         struct dirstat_file *files;
1995         int alloc, nr, permille, cumulative;
1996 };
1997
1998 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1999                 unsigned long changed, const char *base, int baselen)
2000 {
2001         unsigned long this_dir = 0;
2002         unsigned int sources = 0;
2003         const char *line_prefix = diff_line_prefix(opt);
2004
2005         while (dir->nr) {
2006                 struct dirstat_file *f = dir->files;
2007                 int namelen = strlen(f->name);
2008                 unsigned long this;
2009                 char *slash;
2010
2011                 if (namelen < baselen)
2012                         break;
2013                 if (memcmp(f->name, base, baselen))
2014                         break;
2015                 slash = strchr(f->name + baselen, '/');
2016                 if (slash) {
2017                         int newbaselen = slash + 1 - f->name;
2018                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2019                         sources++;
2020                 } else {
2021                         this = f->changed;
2022                         dir->files++;
2023                         dir->nr--;
2024                         sources += 2;
2025                 }
2026                 this_dir += this;
2027         }
2028
2029         /*
2030          * We don't report dirstat's for
2031          *  - the top level
2032          *  - or cases where everything came from a single directory
2033          *    under this directory (sources == 1).
2034          */
2035         if (baselen && sources != 1) {
2036                 if (this_dir) {
2037                         int permille = this_dir * 1000 / changed;
2038                         if (permille >= dir->permille) {
2039                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2040                                         permille / 10, permille % 10, baselen, base);
2041                                 if (!dir->cumulative)
2042                                         return 0;
2043                         }
2044                 }
2045         }
2046         return this_dir;
2047 }
2048
2049 static int dirstat_compare(const void *_a, const void *_b)
2050 {
2051         const struct dirstat_file *a = _a;
2052         const struct dirstat_file *b = _b;
2053         return strcmp(a->name, b->name);
2054 }
2055
2056 static void show_dirstat(struct diff_options *options)
2057 {
2058         int i;
2059         unsigned long changed;
2060         struct dirstat_dir dir;
2061         struct diff_queue_struct *q = &diff_queued_diff;
2062
2063         dir.files = NULL;
2064         dir.alloc = 0;
2065         dir.nr = 0;
2066         dir.permille = options->dirstat_permille;
2067         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2068
2069         changed = 0;
2070         for (i = 0; i < q->nr; i++) {
2071                 struct diff_filepair *p = q->queue[i];
2072                 const char *name;
2073                 unsigned long copied, added, damage;
2074                 int content_changed;
2075
2076                 name = p->two->path ? p->two->path : p->one->path;
2077
2078                 if (p->one->oid_valid && p->two->oid_valid)
2079                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
2080                 else
2081                         content_changed = 1;
2082
2083                 if (!content_changed) {
2084                         /*
2085                          * The SHA1 has not changed, so pre-/post-content is
2086                          * identical. We can therefore skip looking at the
2087                          * file contents altogether.
2088                          */
2089                         damage = 0;
2090                         goto found_damage;
2091                 }
2092
2093                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2094                         /*
2095                          * In --dirstat-by-file mode, we don't really need to
2096                          * look at the actual file contents at all.
2097                          * The fact that the SHA1 changed is enough for us to
2098                          * add this file to the list of results
2099                          * (with each file contributing equal damage).
2100                          */
2101                         damage = 1;
2102                         goto found_damage;
2103                 }
2104
2105                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2106                         diff_populate_filespec(p->one, 0);
2107                         diff_populate_filespec(p->two, 0);
2108                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2109                                                &copied, &added);
2110                         diff_free_filespec_data(p->one);
2111                         diff_free_filespec_data(p->two);
2112                 } else if (DIFF_FILE_VALID(p->one)) {
2113                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2114                         copied = added = 0;
2115                         diff_free_filespec_data(p->one);
2116                 } else if (DIFF_FILE_VALID(p->two)) {
2117                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2118                         copied = 0;
2119                         added = p->two->size;
2120                         diff_free_filespec_data(p->two);
2121                 } else
2122                         continue;
2123
2124                 /*
2125                  * Original minus copied is the removed material,
2126                  * added is the new material.  They are both damages
2127                  * made to the preimage.
2128                  * If the resulting damage is zero, we know that
2129                  * diffcore_count_changes() considers the two entries to
2130                  * be identical, but since content_changed is true, we
2131                  * know that there must have been _some_ kind of change,
2132                  * so we force all entries to have damage > 0.
2133                  */
2134                 damage = (p->one->size - copied) + added;
2135                 if (!damage)
2136                         damage = 1;
2137
2138 found_damage:
2139                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2140                 dir.files[dir.nr].name = name;
2141                 dir.files[dir.nr].changed = damage;
2142                 changed += damage;
2143                 dir.nr++;
2144         }
2145
2146         /* This can happen even with many files, if everything was renames */
2147         if (!changed)
2148                 return;
2149
2150         /* Show all directories with more than x% of the changes */
2151         QSORT(dir.files, dir.nr, dirstat_compare);
2152         gather_dirstat(options, &dir, changed, "", 0);
2153 }
2154
2155 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2156 {
2157         int i;
2158         unsigned long changed;
2159         struct dirstat_dir dir;
2160
2161         if (data->nr == 0)
2162                 return;
2163
2164         dir.files = NULL;
2165         dir.alloc = 0;
2166         dir.nr = 0;
2167         dir.permille = options->dirstat_permille;
2168         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2169
2170         changed = 0;
2171         for (i = 0; i < data->nr; i++) {
2172                 struct diffstat_file *file = data->files[i];
2173                 unsigned long damage = file->added + file->deleted;
2174                 if (file->is_binary)
2175                         /*
2176                          * binary files counts bytes, not lines. Must find some
2177                          * way to normalize binary bytes vs. textual lines.
2178                          * The following heuristic assumes that there are 64
2179                          * bytes per "line".
2180                          * This is stupid and ugly, but very cheap...
2181                          */
2182                         damage = (damage + 63) / 64;
2183                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2184                 dir.files[dir.nr].name = file->name;
2185                 dir.files[dir.nr].changed = damage;
2186                 changed += damage;
2187                 dir.nr++;
2188         }
2189
2190         /* This can happen even with many files, if everything was renames */
2191         if (!changed)
2192                 return;
2193
2194         /* Show all directories with more than x% of the changes */
2195         QSORT(dir.files, dir.nr, dirstat_compare);
2196         gather_dirstat(options, &dir, changed, "", 0);
2197 }
2198
2199 static void free_diffstat_info(struct diffstat_t *diffstat)
2200 {
2201         int i;
2202         for (i = 0; i < diffstat->nr; i++) {
2203                 struct diffstat_file *f = diffstat->files[i];
2204                 if (f->name != f->print_name)
2205                         free(f->print_name);
2206                 free(f->name);
2207                 free(f->from_name);
2208                 free(f);
2209         }
2210         free(diffstat->files);
2211 }
2212
2213 struct checkdiff_t {
2214         const char *filename;
2215         int lineno;
2216         int conflict_marker_size;
2217         struct diff_options *o;
2218         unsigned ws_rule;
2219         unsigned status;
2220 };
2221
2222 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2223 {
2224         char firstchar;
2225         int cnt;
2226
2227         if (len < marker_size + 1)
2228                 return 0;
2229         firstchar = line[0];
2230         switch (firstchar) {
2231         case '=': case '>': case '<': case '|':
2232                 break;
2233         default:
2234                 return 0;
2235         }
2236         for (cnt = 1; cnt < marker_size; cnt++)
2237                 if (line[cnt] != firstchar)
2238                         return 0;
2239         /* line[1] thru line[marker_size-1] are same as firstchar */
2240         if (len < marker_size + 1 || !isspace(line[marker_size]))
2241                 return 0;
2242         return 1;
2243 }
2244
2245 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2246 {
2247         struct checkdiff_t *data = priv;
2248         int marker_size = data->conflict_marker_size;
2249         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2250         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2251         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2252         char *err;
2253         const char *line_prefix;
2254
2255         assert(data->o);
2256         line_prefix = diff_line_prefix(data->o);
2257
2258         if (line[0] == '+') {
2259                 unsigned bad;
2260                 data->lineno++;
2261                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2262                         data->status |= 1;
2263                         fprintf(data->o->file,
2264                                 "%s%s:%d: leftover conflict marker\n",
2265                                 line_prefix, data->filename, data->lineno);
2266                 }
2267                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2268                 if (!bad)
2269                         return;
2270                 data->status |= bad;
2271                 err = whitespace_error_string(bad);
2272                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2273                         line_prefix, data->filename, data->lineno, err);
2274                 free(err);
2275                 emit_line(data->o, set, reset, line, 1);
2276                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2277                               data->o->file, set, reset, ws);
2278         } else if (line[0] == ' ') {
2279                 data->lineno++;
2280         } else if (line[0] == '@') {
2281                 char *plus = strchr(line, '+');
2282                 if (plus)
2283                         data->lineno = strtol(plus, NULL, 10) - 1;
2284                 else
2285                         die("invalid diff");
2286         }
2287 }
2288
2289 static unsigned char *deflate_it(char *data,
2290                                  unsigned long size,
2291                                  unsigned long *result_size)
2292 {
2293         int bound;
2294         unsigned char *deflated;
2295         git_zstream stream;
2296
2297         git_deflate_init(&stream, zlib_compression_level);
2298         bound = git_deflate_bound(&stream, size);
2299         deflated = xmalloc(bound);
2300         stream.next_out = deflated;
2301         stream.avail_out = bound;
2302
2303         stream.next_in = (unsigned char *)data;
2304         stream.avail_in = size;
2305         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2306                 ; /* nothing */
2307         git_deflate_end(&stream);
2308         *result_size = stream.total_out;
2309         return deflated;
2310 }
2311
2312 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2313                                   const char *prefix)
2314 {
2315         void *cp;
2316         void *delta;
2317         void *deflated;
2318         void *data;
2319         unsigned long orig_size;
2320         unsigned long delta_size;
2321         unsigned long deflate_size;
2322         unsigned long data_size;
2323
2324         /* We could do deflated delta, or we could do just deflated two,
2325          * whichever is smaller.
2326          */
2327         delta = NULL;
2328         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2329         if (one->size && two->size) {
2330                 delta = diff_delta(one->ptr, one->size,
2331                                    two->ptr, two->size,
2332                                    &delta_size, deflate_size);
2333                 if (delta) {
2334                         void *to_free = delta;
2335                         orig_size = delta_size;
2336                         delta = deflate_it(delta, delta_size, &delta_size);
2337                         free(to_free);
2338                 }
2339         }
2340
2341         if (delta && delta_size < deflate_size) {
2342                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2343                 free(deflated);
2344                 data = delta;
2345                 data_size = delta_size;
2346         }
2347         else {
2348                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2349                 free(delta);
2350                 data = deflated;
2351                 data_size = deflate_size;
2352         }
2353
2354         /* emit data encoded in base85 */
2355         cp = data;
2356         while (data_size) {
2357                 int bytes = (52 < data_size) ? 52 : data_size;
2358                 char line[70];
2359                 data_size -= bytes;
2360                 if (bytes <= 26)
2361                         line[0] = bytes + 'A' - 1;
2362                 else
2363                         line[0] = bytes - 26 + 'a' - 1;
2364                 encode_85(line + 1, cp, bytes);
2365                 cp = (char *) cp + bytes;
2366                 fprintf(file, "%s", prefix);
2367                 fputs(line, file);
2368                 fputc('\n', file);
2369         }
2370         fprintf(file, "%s\n", prefix);
2371         free(data);
2372 }
2373
2374 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2375                              const char *prefix)
2376 {
2377         fprintf(file, "%sGIT binary patch\n", prefix);
2378         emit_binary_diff_body(file, one, two, prefix);
2379         emit_binary_diff_body(file, two, one, prefix);
2380 }
2381
2382 int diff_filespec_is_binary(struct diff_filespec *one)
2383 {
2384         if (one->is_binary == -1) {
2385                 diff_filespec_load_driver(one);
2386                 if (one->driver->binary != -1)
2387                         one->is_binary = one->driver->binary;
2388                 else {
2389                         if (!one->data && DIFF_FILE_VALID(one))
2390                                 diff_populate_filespec(one, CHECK_BINARY);
2391                         if (one->is_binary == -1 && one->data)
2392                                 one->is_binary = buffer_is_binary(one->data,
2393                                                 one->size);
2394                         if (one->is_binary == -1)
2395                                 one->is_binary = 0;
2396                 }
2397         }
2398         return one->is_binary;
2399 }
2400
2401 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2402 {
2403         diff_filespec_load_driver(one);
2404         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2405 }
2406
2407 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2408 {
2409         if (!options->a_prefix)
2410                 options->a_prefix = a;
2411         if (!options->b_prefix)
2412                 options->b_prefix = b;
2413 }
2414
2415 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2416 {
2417         if (!DIFF_FILE_VALID(one))
2418                 return NULL;
2419
2420         diff_filespec_load_driver(one);
2421         return userdiff_get_textconv(one->driver);
2422 }
2423
2424 static void builtin_diff(const char *name_a,
2425                          const char *name_b,
2426                          struct diff_filespec *one,
2427                          struct diff_filespec *two,
2428                          const char *xfrm_msg,
2429                          int must_show_header,
2430                          struct diff_options *o,
2431                          int complete_rewrite)
2432 {
2433         mmfile_t mf1, mf2;
2434         const char *lbl[2];
2435         char *a_one, *b_two;
2436         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2437         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2438         const char *a_prefix, *b_prefix;
2439         struct userdiff_driver *textconv_one = NULL;
2440         struct userdiff_driver *textconv_two = NULL;
2441         struct strbuf header = STRBUF_INIT;
2442         const char *line_prefix = diff_line_prefix(o);
2443
2444         diff_set_mnemonic_prefix(o, "a/", "b/");
2445         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2446                 a_prefix = o->b_prefix;
2447                 b_prefix = o->a_prefix;
2448         } else {
2449                 a_prefix = o->a_prefix;
2450                 b_prefix = o->b_prefix;
2451         }
2452
2453         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
2454             (!one->mode || S_ISGITLINK(one->mode)) &&
2455             (!two->mode || S_ISGITLINK(two->mode))) {
2456                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2457                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2458                 show_submodule_summary(o->file, one->path ? one->path : two->path,
2459                                 line_prefix,
2460                                 &one->oid, &two->oid,
2461                                 two->dirty_submodule,
2462                                 meta, del, add, reset);
2463                 return;
2464         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
2465                    (!one->mode || S_ISGITLINK(one->mode)) &&
2466                    (!two->mode || S_ISGITLINK(two->mode))) {
2467                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2468                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2469                 show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
2470                                 line_prefix,
2471                                 &one->oid, &two->oid,
2472                                 two->dirty_submodule,
2473                                 meta, del, add, reset, o);
2474                 return;
2475         }
2476
2477         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2478                 textconv_one = get_textconv(one);
2479                 textconv_two = get_textconv(two);
2480         }
2481
2482         /* Never use a non-valid filename anywhere if at all possible */
2483         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2484         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2485
2486         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2487         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2488         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2489         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2490         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2491         if (lbl[0][0] == '/') {
2492                 /* /dev/null */
2493                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2494                 if (xfrm_msg)
2495                         strbuf_addstr(&header, xfrm_msg);
2496                 must_show_header = 1;
2497         }
2498         else if (lbl[1][0] == '/') {
2499                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2500                 if (xfrm_msg)
2501                         strbuf_addstr(&header, xfrm_msg);
2502                 must_show_header = 1;
2503         }
2504         else {
2505                 if (one->mode != two->mode) {
2506                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2507                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2508                         must_show_header = 1;
2509                 }
2510                 if (xfrm_msg)
2511                         strbuf_addstr(&header, xfrm_msg);
2512
2513                 /*
2514                  * we do not run diff between different kind
2515                  * of objects.
2516                  */
2517                 if ((one->mode ^ two->mode) & S_IFMT)
2518                         goto free_ab_and_return;
2519                 if (complete_rewrite &&
2520                     (textconv_one || !diff_filespec_is_binary(one)) &&
2521                     (textconv_two || !diff_filespec_is_binary(two))) {
2522                         fprintf(o->file, "%s", header.buf);
2523                         strbuf_reset(&header);
2524                         emit_rewrite_diff(name_a, name_b, one, two,
2525                                                 textconv_one, textconv_two, o);
2526                         o->found_changes = 1;
2527                         goto free_ab_and_return;
2528                 }
2529         }
2530
2531         if (o->irreversible_delete && lbl[1][0] == '/') {
2532                 fprintf(o->file, "%s", header.buf);
2533                 strbuf_reset(&header);
2534                 goto free_ab_and_return;
2535         } else if (!DIFF_OPT_TST(o, TEXT) &&
2536             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2537               (!textconv_two && diff_filespec_is_binary(two)) )) {
2538                 if (!one->data && !two->data &&
2539                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
2540                     !DIFF_OPT_TST(o, BINARY)) {
2541                         if (!oidcmp(&one->oid, &two->oid)) {
2542                                 if (must_show_header)
2543                                         fprintf(o->file, "%s", header.buf);
2544                                 goto free_ab_and_return;
2545                         }
2546                         fprintf(o->file, "%s", header.buf);
2547                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2548                                 line_prefix, lbl[0], lbl[1]);
2549                         goto free_ab_and_return;
2550                 }
2551                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2552                         die("unable to read files to diff");
2553                 /* Quite common confusing case */
2554                 if (mf1.size == mf2.size &&
2555                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2556                         if (must_show_header)
2557                                 fprintf(o->file, "%s", header.buf);
2558                         goto free_ab_and_return;
2559                 }
2560                 fprintf(o->file, "%s", header.buf);
2561                 strbuf_reset(&header);
2562                 if (DIFF_OPT_TST(o, BINARY))
2563                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2564                 else
2565                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2566                                 line_prefix, lbl[0], lbl[1]);
2567                 o->found_changes = 1;
2568         } else {
2569                 /* Crazy xdl interfaces.. */
2570                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2571                 const char *v;
2572                 xpparam_t xpp;
2573                 xdemitconf_t xecfg;
2574                 struct emit_callback ecbdata;
2575                 const struct userdiff_funcname *pe;
2576
2577                 if (must_show_header) {
2578                         fprintf(o->file, "%s", header.buf);
2579                         strbuf_reset(&header);
2580                 }
2581
2582                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2583                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2584
2585                 pe = diff_funcname_pattern(one);
2586                 if (!pe)
2587                         pe = diff_funcname_pattern(two);
2588
2589                 memset(&xpp, 0, sizeof(xpp));
2590                 memset(&xecfg, 0, sizeof(xecfg));
2591                 memset(&ecbdata, 0, sizeof(ecbdata));
2592                 ecbdata.label_path = lbl;
2593                 ecbdata.color_diff = want_color(o->use_color);
2594                 ecbdata.ws_rule = whitespace_rule(name_b);
2595                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2596                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2597                 ecbdata.opt = o;
2598                 ecbdata.header = header.len ? &header : NULL;
2599                 xpp.flags = o->xdl_opts;
2600                 xecfg.ctxlen = o->context;
2601                 xecfg.interhunkctxlen = o->interhunkcontext;
2602                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2603                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2604                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2605                 if (pe)
2606                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2607                 if (!diffopts)
2608                         ;
2609                 else if (skip_prefix(diffopts, "--unified=", &v))
2610                         xecfg.ctxlen = strtoul(v, NULL, 10);
2611                 else if (skip_prefix(diffopts, "-u", &v))
2612                         xecfg.ctxlen = strtoul(v, NULL, 10);
2613                 if (o->word_diff)
2614                         init_diff_words_data(&ecbdata, o, one, two);
2615                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2616                                   &xpp, &xecfg))
2617                         die("unable to generate diff for %s", one->path);
2618                 if (o->word_diff)
2619                         free_diff_words_data(&ecbdata);
2620                 if (textconv_one)
2621                         free(mf1.ptr);
2622                 if (textconv_two)
2623                         free(mf2.ptr);
2624                 xdiff_clear_find_func(&xecfg);
2625         }
2626
2627  free_ab_and_return:
2628         strbuf_release(&header);
2629         diff_free_filespec_data(one);
2630         diff_free_filespec_data(two);
2631         free(a_one);
2632         free(b_two);
2633         return;
2634 }
2635
2636 static void builtin_diffstat(const char *name_a, const char *name_b,
2637                              struct diff_filespec *one,
2638                              struct diff_filespec *two,
2639                              struct diffstat_t *diffstat,
2640                              struct diff_options *o,
2641                              struct diff_filepair *p)
2642 {
2643         mmfile_t mf1, mf2;
2644         struct diffstat_file *data;
2645         int same_contents;
2646         int complete_rewrite = 0;
2647
2648         if (!DIFF_PAIR_UNMERGED(p)) {
2649                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2650                         complete_rewrite = 1;
2651         }
2652
2653         data = diffstat_add(diffstat, name_a, name_b);
2654         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2655
2656         if (!one || !two) {
2657                 data->is_unmerged = 1;
2658                 return;
2659         }
2660
2661         same_contents = !oidcmp(&one->oid, &two->oid);
2662
2663         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2664                 data->is_binary = 1;
2665                 if (same_contents) {
2666                         data->added = 0;
2667                         data->deleted = 0;
2668                 } else {
2669                         data->added = diff_filespec_size(two);
2670                         data->deleted = diff_filespec_size(one);
2671                 }
2672         }
2673
2674         else if (complete_rewrite) {
2675                 diff_populate_filespec(one, 0);
2676                 diff_populate_filespec(two, 0);
2677                 data->deleted = count_lines(one->data, one->size);
2678                 data->added = count_lines(two->data, two->size);
2679         }
2680
2681         else if (!same_contents) {
2682                 /* Crazy xdl interfaces.. */
2683                 xpparam_t xpp;
2684                 xdemitconf_t xecfg;
2685
2686                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2687                         die("unable to read files to diff");
2688
2689                 memset(&xpp, 0, sizeof(xpp));
2690                 memset(&xecfg, 0, sizeof(xecfg));
2691                 xpp.flags = o->xdl_opts;
2692                 xecfg.ctxlen = o->context;
2693                 xecfg.interhunkctxlen = o->interhunkcontext;
2694                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2695                                   &xpp, &xecfg))
2696                         die("unable to generate diffstat for %s", one->path);
2697         }
2698
2699         diff_free_filespec_data(one);
2700         diff_free_filespec_data(two);
2701 }
2702
2703 static void builtin_checkdiff(const char *name_a, const char *name_b,
2704                               const char *attr_path,
2705                               struct diff_filespec *one,
2706                               struct diff_filespec *two,
2707                               struct diff_options *o)
2708 {
2709         mmfile_t mf1, mf2;
2710         struct checkdiff_t data;
2711
2712         if (!two)
2713                 return;
2714
2715         memset(&data, 0, sizeof(data));
2716         data.filename = name_b ? name_b : name_a;
2717         data.lineno = 0;
2718         data.o = o;
2719         data.ws_rule = whitespace_rule(attr_path);
2720         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2721
2722         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2723                 die("unable to read files to diff");
2724
2725         /*
2726          * All the other codepaths check both sides, but not checking
2727          * the "old" side here is deliberate.  We are checking the newly
2728          * introduced changes, and as long as the "new" side is text, we
2729          * can and should check what it introduces.
2730          */
2731         if (diff_filespec_is_binary(two))
2732                 goto free_and_return;
2733         else {
2734                 /* Crazy xdl interfaces.. */
2735                 xpparam_t xpp;
2736                 xdemitconf_t xecfg;
2737
2738                 memset(&xpp, 0, sizeof(xpp));
2739                 memset(&xecfg, 0, sizeof(xecfg));
2740                 xecfg.ctxlen = 1; /* at least one context line */
2741                 xpp.flags = 0;
2742                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2743                                   &xpp, &xecfg))
2744                         die("unable to generate checkdiff for %s", one->path);
2745
2746                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2747                         struct emit_callback ecbdata;
2748                         int blank_at_eof;
2749
2750                         ecbdata.ws_rule = data.ws_rule;
2751                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2752                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2753
2754                         if (blank_at_eof) {
2755                                 static char *err;
2756                                 if (!err)
2757                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2758                                 fprintf(o->file, "%s:%d: %s.\n",
2759                                         data.filename, blank_at_eof, err);
2760                                 data.status = 1; /* report errors */
2761                         }
2762                 }
2763         }
2764  free_and_return:
2765         diff_free_filespec_data(one);
2766         diff_free_filespec_data(two);
2767         if (data.status)
2768                 DIFF_OPT_SET(o, CHECK_FAILED);
2769 }
2770
2771 struct diff_filespec *alloc_filespec(const char *path)
2772 {
2773         struct diff_filespec *spec;
2774
2775         FLEXPTR_ALLOC_STR(spec, path, path);
2776         spec->count = 1;
2777         spec->is_binary = -1;
2778         return spec;
2779 }
2780
2781 void free_filespec(struct diff_filespec *spec)
2782 {
2783         if (!--spec->count) {
2784                 diff_free_filespec_data(spec);
2785                 free(spec);
2786         }
2787 }
2788
2789 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
2790                    int oid_valid, unsigned short mode)
2791 {
2792         if (mode) {
2793                 spec->mode = canon_mode(mode);
2794                 oidcpy(&spec->oid, oid);
2795                 spec->oid_valid = oid_valid;
2796         }
2797 }
2798
2799 /*
2800  * Given a name and sha1 pair, if the index tells us the file in
2801  * the work tree has that object contents, return true, so that
2802  * prepare_temp_file() does not have to inflate and extract.
2803  */
2804 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
2805 {
2806         const struct cache_entry *ce;
2807         struct stat st;
2808         int pos, len;
2809
2810         /*
2811          * We do not read the cache ourselves here, because the
2812          * benchmark with my previous version that always reads cache
2813          * shows that it makes things worse for diff-tree comparing
2814          * two linux-2.6 kernel trees in an already checked out work
2815          * tree.  This is because most diff-tree comparisons deal with
2816          * only a small number of files, while reading the cache is
2817          * expensive for a large project, and its cost outweighs the
2818          * savings we get by not inflating the object to a temporary
2819          * file.  Practically, this code only helps when we are used
2820          * by diff-cache --cached, which does read the cache before
2821          * calling us.
2822          */
2823         if (!active_cache)
2824                 return 0;
2825
2826         /* We want to avoid the working directory if our caller
2827          * doesn't need the data in a normal file, this system
2828          * is rather slow with its stat/open/mmap/close syscalls,
2829          * and the object is contained in a pack file.  The pack
2830          * is probably already open and will be faster to obtain
2831          * the data through than the working directory.  Loose
2832          * objects however would tend to be slower as they need
2833          * to be individually opened and inflated.
2834          */
2835         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
2836                 return 0;
2837
2838         /*
2839          * Similarly, if we'd have to convert the file contents anyway, that
2840          * makes the optimization not worthwhile.
2841          */
2842         if (!want_file && would_convert_to_git(&the_index, name))
2843                 return 0;
2844
2845         len = strlen(name);
2846         pos = cache_name_pos(name, len);
2847         if (pos < 0)
2848                 return 0;
2849         ce = active_cache[pos];
2850
2851         /*
2852          * This is not the sha1 we are looking for, or
2853          * unreusable because it is not a regular file.
2854          */
2855         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
2856                 return 0;
2857
2858         /*
2859          * If ce is marked as "assume unchanged", there is no
2860          * guarantee that work tree matches what we are looking for.
2861          */
2862         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2863                 return 0;
2864
2865         /*
2866          * If ce matches the file in the work tree, we can reuse it.
2867          */
2868         if (ce_uptodate(ce) ||
2869             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2870                 return 1;
2871
2872         return 0;
2873 }
2874
2875 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2876 {
2877         struct strbuf buf = STRBUF_INIT;
2878         char *dirty = "";
2879
2880         /* Are we looking at the work tree? */
2881         if (s->dirty_submodule)
2882                 dirty = "-dirty";
2883
2884         strbuf_addf(&buf, "Subproject commit %s%s\n",
2885                     oid_to_hex(&s->oid), dirty);
2886         s->size = buf.len;
2887         if (size_only) {
2888                 s->data = NULL;
2889                 strbuf_release(&buf);
2890         } else {
2891                 s->data = strbuf_detach(&buf, NULL);
2892                 s->should_free = 1;
2893         }
2894         return 0;
2895 }
2896
2897 /*
2898  * While doing rename detection and pickaxe operation, we may need to
2899  * grab the data for the blob (or file) for our own in-core comparison.
2900  * diff_filespec has data and size fields for this purpose.
2901  */
2902 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2903 {
2904         int size_only = flags & CHECK_SIZE_ONLY;
2905         int err = 0;
2906         /*
2907          * demote FAIL to WARN to allow inspecting the situation
2908          * instead of refusing.
2909          */
2910         enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2911                                     ? SAFE_CRLF_WARN
2912                                     : safe_crlf);
2913
2914         if (!DIFF_FILE_VALID(s))
2915                 die("internal error: asking to populate invalid file.");
2916         if (S_ISDIR(s->mode))
2917                 return -1;
2918
2919         if (s->data)
2920                 return 0;
2921
2922         if (size_only && 0 < s->size)
2923                 return 0;
2924
2925         if (S_ISGITLINK(s->mode))
2926                 return diff_populate_gitlink(s, size_only);
2927
2928         if (!s->oid_valid ||
2929             reuse_worktree_file(s->path, &s->oid, 0)) {
2930                 struct strbuf buf = STRBUF_INIT;
2931                 struct stat st;
2932                 int fd;
2933
2934                 if (lstat(s->path, &st) < 0) {
2935                         if (errno == ENOENT) {
2936                         err_empty:
2937                                 err = -1;
2938                         empty:
2939                                 s->data = (char *)"";
2940                                 s->size = 0;
2941                                 return err;
2942                         }
2943                 }
2944                 s->size = xsize_t(st.st_size);
2945                 if (!s->size)
2946                         goto empty;
2947                 if (S_ISLNK(st.st_mode)) {
2948                         struct strbuf sb = STRBUF_INIT;
2949
2950                         if (strbuf_readlink(&sb, s->path, s->size))
2951                                 goto err_empty;
2952                         s->size = sb.len;
2953                         s->data = strbuf_detach(&sb, NULL);
2954                         s->should_free = 1;
2955                         return 0;
2956                 }
2957
2958                 /*
2959                  * Even if the caller would be happy with getting
2960                  * only the size, we cannot return early at this
2961                  * point if the path requires us to run the content
2962                  * conversion.
2963                  */
2964                 if (size_only && !would_convert_to_git(&the_index, s->path))
2965                         return 0;
2966
2967                 /*
2968                  * Note: this check uses xsize_t(st.st_size) that may
2969                  * not be the true size of the blob after it goes
2970                  * through convert_to_git().  This may not strictly be
2971                  * correct, but the whole point of big_file_threshold
2972                  * and is_binary check being that we want to avoid
2973                  * opening the file and inspecting the contents, this
2974                  * is probably fine.
2975                  */
2976                 if ((flags & CHECK_BINARY) &&
2977                     s->size > big_file_threshold && s->is_binary == -1) {
2978                         s->is_binary = 1;
2979                         return 0;
2980                 }
2981                 fd = open(s->path, O_RDONLY);
2982                 if (fd < 0)
2983                         goto err_empty;
2984                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2985                 close(fd);
2986                 s->should_munmap = 1;
2987
2988                 /*
2989                  * Convert from working tree format to canonical git format
2990                  */
2991                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
2992                         size_t size = 0;
2993                         munmap(s->data, s->size);
2994                         s->should_munmap = 0;
2995                         s->data = strbuf_detach(&buf, &size);
2996                         s->size = size;
2997                         s->should_free = 1;
2998                 }
2999         }
3000         else {
3001                 enum object_type type;
3002                 if (size_only || (flags & CHECK_BINARY)) {
3003                         type = sha1_object_info(s->oid.hash, &s->size);
3004                         if (type < 0)
3005                                 die("unable to read %s",
3006                                     oid_to_hex(&s->oid));
3007                         if (size_only)
3008                                 return 0;
3009                         if (s->size > big_file_threshold && s->is_binary == -1) {
3010                                 s->is_binary = 1;
3011                                 return 0;
3012                         }
3013                 }
3014                 s->data = read_sha1_file(s->oid.hash, &type, &s->size);
3015                 if (!s->data)
3016                         die("unable to read %s", oid_to_hex(&s->oid));
3017                 s->should_free = 1;
3018         }
3019         return 0;
3020 }
3021
3022 void diff_free_filespec_blob(struct diff_filespec *s)
3023 {
3024         if (s->should_free)
3025                 free(s->data);
3026         else if (s->should_munmap)
3027                 munmap(s->data, s->size);
3028
3029         if (s->should_free || s->should_munmap) {
3030                 s->should_free = s->should_munmap = 0;
3031                 s->data = NULL;
3032         }
3033 }
3034
3035 void diff_free_filespec_data(struct diff_filespec *s)
3036 {
3037         diff_free_filespec_blob(s);
3038         FREE_AND_NULL(s->cnt_data);
3039 }
3040
3041 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3042                            void *blob,
3043                            unsigned long size,
3044                            const struct object_id *oid,
3045                            int mode)
3046 {
3047         int fd;
3048         struct strbuf buf = STRBUF_INIT;
3049         struct strbuf template = STRBUF_INIT;
3050         char *path_dup = xstrdup(path);
3051         const char *base = basename(path_dup);
3052
3053         /* Generate "XXXXXX_basename.ext" */
3054         strbuf_addstr(&template, "XXXXXX_");
3055         strbuf_addstr(&template, base);
3056
3057         fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
3058         if (fd < 0)
3059                 die_errno("unable to create temp-file");
3060         if (convert_to_working_tree(path,
3061                         (const char *)blob, (size_t)size, &buf)) {
3062                 blob = buf.buf;
3063                 size = buf.len;
3064         }
3065         if (write_in_full(fd, blob, size) != size)
3066                 die_errno("unable to write temp-file");
3067         close_tempfile(&temp->tempfile);
3068         temp->name = get_tempfile_path(&temp->tempfile);
3069         oid_to_hex_r(temp->hex, oid);
3070         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3071         strbuf_release(&buf);
3072         strbuf_release(&template);
3073         free(path_dup);
3074 }
3075
3076 static struct diff_tempfile *prepare_temp_file(const char *name,
3077                 struct diff_filespec *one)
3078 {
3079         struct diff_tempfile *temp = claim_diff_tempfile();
3080
3081         if (!DIFF_FILE_VALID(one)) {
3082         not_a_valid_file:
3083                 /* A '-' entry produces this for file-2, and
3084                  * a '+' entry produces this for file-1.
3085                  */
3086                 temp->name = "/dev/null";
3087                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3088                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3089                 return temp;
3090         }
3091
3092         if (!S_ISGITLINK(one->mode) &&
3093             (!one->oid_valid ||
3094              reuse_worktree_file(name, &one->oid, 1))) {
3095                 struct stat st;
3096                 if (lstat(name, &st) < 0) {
3097                         if (errno == ENOENT)
3098                                 goto not_a_valid_file;
3099                         die_errno("stat(%s)", name);
3100                 }
3101                 if (S_ISLNK(st.st_mode)) {
3102                         struct strbuf sb = STRBUF_INIT;
3103                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3104                                 die_errno("readlink(%s)", name);
3105                         prep_temp_blob(name, temp, sb.buf, sb.len,
3106                                        (one->oid_valid ?
3107                                         &one->oid : &null_oid),
3108                                        (one->oid_valid ?
3109                                         one->mode : S_IFLNK));
3110                         strbuf_release(&sb);
3111                 }
3112                 else {
3113                         /* we can borrow from the file in the work tree */
3114                         temp->name = name;
3115                         if (!one->oid_valid)
3116                                 oid_to_hex_r(temp->hex, &null_oid);
3117                         else
3118                                 oid_to_hex_r(temp->hex, &one->oid);
3119                         /* Even though we may sometimes borrow the
3120                          * contents from the work tree, we always want
3121                          * one->mode.  mode is trustworthy even when
3122                          * !(one->oid_valid), as long as
3123                          * DIFF_FILE_VALID(one).
3124                          */
3125                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3126                 }
3127                 return temp;
3128         }
3129         else {
3130                 if (diff_populate_filespec(one, 0))
3131                         die("cannot read data blob for %s", one->path);
3132                 prep_temp_blob(name, temp, one->data, one->size,
3133                                &one->oid, one->mode);
3134         }
3135         return temp;
3136 }
3137
3138 static void add_external_diff_name(struct argv_array *argv,
3139                                    const char *name,
3140                                    struct diff_filespec *df)
3141 {
3142         struct diff_tempfile *temp = prepare_temp_file(name, df);
3143         argv_array_push(argv, temp->name);
3144         argv_array_push(argv, temp->hex);
3145         argv_array_push(argv, temp->mode);
3146 }
3147
3148 /* An external diff command takes:
3149  *
3150  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3151  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3152  *
3153  */
3154 static void run_external_diff(const char *pgm,
3155                               const char *name,
3156                               const char *other,
3157                               struct diff_filespec *one,
3158                               struct diff_filespec *two,
3159                               const char *xfrm_msg,
3160                               int complete_rewrite,
3161                               struct diff_options *o)
3162 {
3163         struct argv_array argv = ARGV_ARRAY_INIT;
3164         struct argv_array env = ARGV_ARRAY_INIT;
3165         struct diff_queue_struct *q = &diff_queued_diff;
3166
3167         argv_array_push(&argv, pgm);
3168         argv_array_push(&argv, name);
3169
3170         if (one && two) {
3171                 add_external_diff_name(&argv, name, one);
3172                 if (!other)
3173                         add_external_diff_name(&argv, name, two);
3174                 else {
3175                         add_external_diff_name(&argv, other, two);
3176                         argv_array_push(&argv, other);
3177                         argv_array_push(&argv, xfrm_msg);
3178                 }
3179         }
3180
3181         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3182         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3183
3184         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3185                 die(_("external diff died, stopping at %s"), name);
3186
3187         remove_tempfile();
3188         argv_array_clear(&argv);
3189         argv_array_clear(&env);
3190 }
3191
3192 static int similarity_index(struct diff_filepair *p)
3193 {
3194         return p->score * 100 / MAX_SCORE;
3195 }
3196
3197 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3198 {
3199         if (startup_info->have_repository)
3200                 return find_unique_abbrev(oid->hash, abbrev);
3201         else {
3202                 char *hex = oid_to_hex(oid);
3203                 if (abbrev < 0)
3204                         abbrev = FALLBACK_DEFAULT_ABBREV;
3205                 if (abbrev > GIT_SHA1_HEXSZ)
3206                         die("BUG: oid abbreviation out of range: %d", abbrev);
3207                 if (abbrev)
3208                         hex[abbrev] = '\0';
3209                 return hex;
3210         }
3211 }
3212
3213 static void fill_metainfo(struct strbuf *msg,
3214                           const char *name,
3215                           const char *other,
3216                           struct diff_filespec *one,
3217                           struct diff_filespec *two,
3218                           struct diff_options *o,
3219                           struct diff_filepair *p,
3220                           int *must_show_header,
3221                           int use_color)
3222 {
3223         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3224         const char *reset = diff_get_color(use_color, DIFF_RESET);
3225         const char *line_prefix = diff_line_prefix(o);
3226
3227         *must_show_header = 1;
3228         strbuf_init(msg, PATH_MAX * 2 + 300);
3229         switch (p->status) {
3230         case DIFF_STATUS_COPIED:
3231                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3232                             line_prefix, set, similarity_index(p));
3233                 strbuf_addf(msg, "%s\n%s%scopy from ",
3234                             reset,  line_prefix, set);
3235                 quote_c_style(name, msg, NULL, 0);
3236                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3237                 quote_c_style(other, msg, NULL, 0);
3238                 strbuf_addf(msg, "%s\n", reset);
3239                 break;
3240         case DIFF_STATUS_RENAMED:
3241                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3242                             line_prefix, set, similarity_index(p));
3243                 strbuf_addf(msg, "%s\n%s%srename from ",
3244                             reset, line_prefix, set);
3245                 quote_c_style(name, msg, NULL, 0);
3246                 strbuf_addf(msg, "%s\n%s%srename to ",
3247                             reset, line_prefix, set);
3248                 quote_c_style(other, msg, NULL, 0);
3249                 strbuf_addf(msg, "%s\n", reset);
3250                 break;
3251         case DIFF_STATUS_MODIFIED:
3252                 if (p->score) {
3253                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3254                                     line_prefix,
3255                                     set, similarity_index(p), reset);
3256                         break;
3257                 }
3258                 /* fallthru */
3259         default:
3260                 *must_show_header = 0;
3261         }
3262         if (one && two && oidcmp(&one->oid, &two->oid)) {
3263                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3264
3265                 if (DIFF_OPT_TST(o, BINARY)) {
3266                         mmfile_t mf;
3267                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3268                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3269                                 abbrev = 40;
3270                 }
3271                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3272                             diff_abbrev_oid(&one->oid, abbrev),
3273                             diff_abbrev_oid(&two->oid, abbrev));
3274                 if (one->mode == two->mode)
3275                         strbuf_addf(msg, " %06o", one->mode);
3276                 strbuf_addf(msg, "%s\n", reset);
3277         }
3278 }
3279
3280 static void run_diff_cmd(const char *pgm,
3281                          const char *name,
3282                          const char *other,
3283                          const char *attr_path,
3284                          struct diff_filespec *one,
3285                          struct diff_filespec *two,
3286                          struct strbuf *msg,
3287                          struct diff_options *o,
3288                          struct diff_filepair *p)
3289 {
3290         const char *xfrm_msg = NULL;
3291         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3292         int must_show_header = 0;
3293
3294
3295         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3296                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3297                 if (drv && drv->external)
3298                         pgm = drv->external;
3299         }
3300
3301         if (msg) {
3302                 /*
3303                  * don't use colors when the header is intended for an
3304                  * external diff driver
3305                  */
3306                 fill_metainfo(msg, name, other, one, two, o, p,
3307                               &must_show_header,
3308                               want_color(o->use_color) && !pgm);
3309                 xfrm_msg = msg->len ? msg->buf : NULL;
3310         }
3311
3312         if (pgm) {
3313                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3314                                   complete_rewrite, o);
3315                 return;
3316         }
3317         if (one && two)
3318                 builtin_diff(name, other ? other : name,
3319                              one, two, xfrm_msg, must_show_header,
3320                              o, complete_rewrite);
3321         else
3322                 fprintf(o->file, "* Unmerged path %s\n", name);
3323 }
3324
3325 static void diff_fill_oid_info(struct diff_filespec *one)
3326 {
3327         if (DIFF_FILE_VALID(one)) {
3328                 if (!one->oid_valid) {
3329                         struct stat st;
3330                         if (one->is_stdin) {
3331                                 oidclr(&one->oid);
3332                                 return;
3333                         }
3334                         if (lstat(one->path, &st) < 0)
3335                                 die_errno("stat '%s'", one->path);
3336                         if (index_path(one->oid.hash, one->path, &st, 0))
3337                                 die("cannot hash %s", one->path);
3338                 }
3339         }
3340         else
3341                 oidclr(&one->oid);
3342 }
3343
3344 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3345 {
3346         /* Strip the prefix but do not molest /dev/null and absolute paths */
3347         if (*namep && **namep != '/') {
3348                 *namep += prefix_length;
3349                 if (**namep == '/')
3350                         ++*namep;
3351         }
3352         if (*otherp && **otherp != '/') {
3353                 *otherp += prefix_length;
3354                 if (**otherp == '/')
3355                         ++*otherp;
3356         }
3357 }
3358
3359 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3360 {
3361         const char *pgm = external_diff();
3362         struct strbuf msg;
3363         struct diff_filespec *one = p->one;
3364         struct diff_filespec *two = p->two;
3365         const char *name;
3366         const char *other;
3367         const char *attr_path;
3368
3369         name  = one->path;
3370         other = (strcmp(name, two->path) ? two->path : NULL);
3371         attr_path = name;
3372         if (o->prefix_length)
3373                 strip_prefix(o->prefix_length, &name, &other);
3374
3375         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3376                 pgm = NULL;
3377
3378         if (DIFF_PAIR_UNMERGED(p)) {
3379                 run_diff_cmd(pgm, name, NULL, attr_path,
3380                              NULL, NULL, NULL, o, p);
3381                 return;
3382         }
3383
3384         diff_fill_oid_info(one);
3385         diff_fill_oid_info(two);
3386
3387         if (!pgm &&
3388             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3389             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3390                 /*
3391                  * a filepair that changes between file and symlink
3392                  * needs to be split into deletion and creation.
3393                  */
3394                 struct diff_filespec *null = alloc_filespec(two->path);
3395                 run_diff_cmd(NULL, name, other, attr_path,
3396                              one, null, &msg, o, p);
3397                 free(null);
3398                 strbuf_release(&msg);
3399
3400                 null = alloc_filespec(one->path);
3401                 run_diff_cmd(NULL, name, other, attr_path,
3402                              null, two, &msg, o, p);
3403                 free(null);
3404         }
3405         else
3406                 run_diff_cmd(pgm, name, other, attr_path,
3407                              one, two, &msg, o, p);
3408
3409         strbuf_release(&msg);
3410 }
3411
3412 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3413                          struct diffstat_t *diffstat)
3414 {
3415         const char *name;
3416         const char *other;
3417
3418         if (DIFF_PAIR_UNMERGED(p)) {
3419                 /* unmerged */
3420                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3421                 return;
3422         }
3423
3424         name = p->one->path;
3425         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3426
3427         if (o->prefix_length)
3428                 strip_prefix(o->prefix_length, &name, &other);
3429
3430         diff_fill_oid_info(p->one);
3431         diff_fill_oid_info(p->two);
3432
3433         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3434 }
3435
3436 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3437 {
3438         const char *name;
3439         const char *other;
3440         const char *attr_path;
3441
3442         if (DIFF_PAIR_UNMERGED(p)) {
3443                 /* unmerged */
3444                 return;
3445         }
3446
3447         name = p->one->path;
3448         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3449         attr_path = other ? other : name;
3450
3451         if (o->prefix_length)
3452                 strip_prefix(o->prefix_length, &name, &other);
3453
3454         diff_fill_oid_info(p->one);
3455         diff_fill_oid_info(p->two);
3456
3457         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3458 }
3459
3460 void diff_setup(struct diff_options *options)
3461 {
3462         memcpy(options, &default_diff_options, sizeof(*options));
3463
3464         options->file = stdout;
3465
3466         options->abbrev = DEFAULT_ABBREV;
3467         options->line_termination = '\n';
3468         options->break_opt = -1;
3469         options->rename_limit = -1;
3470         options->dirstat_permille = diff_dirstat_permille_default;
3471         options->context = diff_context_default;
3472         options->interhunkcontext = diff_interhunk_context_default;
3473         options->ws_error_highlight = ws_error_highlight_default;
3474         DIFF_OPT_SET(options, RENAME_EMPTY);
3475
3476         /* pathchange left =NULL by default */
3477         options->change = diff_change;
3478         options->add_remove = diff_addremove;
3479         options->use_color = diff_use_color_default;
3480         options->detect_rename = diff_detect_rename_default;
3481         options->xdl_opts |= diff_algorithm;
3482         if (diff_indent_heuristic)
3483                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
3484
3485         options->orderfile = diff_order_file_cfg;
3486
3487         if (diff_no_prefix) {
3488                 options->a_prefix = options->b_prefix = "";
3489         } else if (!diff_mnemonic_prefix) {
3490                 options->a_prefix = "a/";
3491                 options->b_prefix = "b/";
3492         }
3493 }
3494
3495 void diff_setup_done(struct diff_options *options)
3496 {
3497         int count = 0;
3498
3499         if (options->set_default)
3500                 options->set_default(options);
3501
3502         if (options->output_format & DIFF_FORMAT_NAME)
3503                 count++;
3504         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3505                 count++;
3506         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3507                 count++;
3508         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3509                 count++;
3510         if (count > 1)
3511                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
3512
3513         /*
3514          * Most of the time we can say "there are changes"
3515          * only by checking if there are changed paths, but
3516          * --ignore-whitespace* options force us to look
3517          * inside contents.
3518          */
3519
3520         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3521             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3522             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3523                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3524         else
3525                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3526
3527         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3528                 options->detect_rename = DIFF_DETECT_COPY;
3529
3530         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3531                 options->prefix = NULL;
3532         if (options->prefix)
3533                 options->prefix_length = strlen(options->prefix);
3534         else
3535                 options->prefix_length = 0;
3536
3537         if (options->output_format & (DIFF_FORMAT_NAME |
3538                                       DIFF_FORMAT_NAME_STATUS |
3539                                       DIFF_FORMAT_CHECKDIFF |
3540                                       DIFF_FORMAT_NO_OUTPUT))
3541                 options->output_format &= ~(DIFF_FORMAT_RAW |
3542                                             DIFF_FORMAT_NUMSTAT |
3543                                             DIFF_FORMAT_DIFFSTAT |
3544                                             DIFF_FORMAT_SHORTSTAT |
3545                                             DIFF_FORMAT_DIRSTAT |
3546                                             DIFF_FORMAT_SUMMARY |
3547                                             DIFF_FORMAT_PATCH);
3548
3549         /*
3550          * These cases always need recursive; we do not drop caller-supplied
3551          * recursive bits for other formats here.
3552          */
3553         if (options->output_format & (DIFF_FORMAT_PATCH |
3554                                       DIFF_FORMAT_NUMSTAT |
3555                                       DIFF_FORMAT_DIFFSTAT |
3556                                       DIFF_FORMAT_SHORTSTAT |
3557                                       DIFF_FORMAT_DIRSTAT |
3558                                       DIFF_FORMAT_SUMMARY |
3559                                       DIFF_FORMAT_CHECKDIFF))
3560                 DIFF_OPT_SET(options, RECURSIVE);
3561         /*
3562          * Also pickaxe would not work very well if you do not say recursive
3563          */
3564         if (options->pickaxe)
3565                 DIFF_OPT_SET(options, RECURSIVE);
3566         /*
3567          * When patches are generated, submodules diffed against the work tree
3568          * must be checked for dirtiness too so it can be shown in the output
3569          */
3570         if (options->output_format & DIFF_FORMAT_PATCH)
3571                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3572
3573         if (options->detect_rename && options->rename_limit < 0)
3574                 options->rename_limit = diff_rename_limit_default;
3575         if (options->setup & DIFF_SETUP_USE_CACHE) {
3576                 if (!active_cache)
3577                         /* read-cache does not die even when it fails
3578                          * so it is safe for us to do this here.  Also
3579                          * it does not smudge active_cache or active_nr
3580                          * when it fails, so we do not have to worry about
3581                          * cleaning it up ourselves either.
3582                          */
3583                         read_cache();
3584         }
3585         if (40 < options->abbrev)
3586                 options->abbrev = 40; /* full */
3587
3588         /*
3589          * It does not make sense to show the first hit we happened
3590          * to have found.  It does not make sense not to return with
3591          * exit code in such a case either.
3592          */
3593         if (DIFF_OPT_TST(options, QUICK)) {
3594                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3595                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3596         }
3597
3598         options->diff_path_counter = 0;
3599
3600         if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3601                 die(_("--follow requires exactly one pathspec"));
3602 }
3603
3604 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3605 {
3606         char c, *eq;
3607         int len;
3608
3609         if (*arg != '-')
3610                 return 0;
3611         c = *++arg;
3612         if (!c)
3613                 return 0;
3614         if (c == arg_short) {
3615                 c = *++arg;
3616                 if (!c)
3617                         return 1;
3618                 if (val && isdigit(c)) {
3619                         char *end;
3620                         int n = strtoul(arg, &end, 10);
3621                         if (*end)
3622                                 return 0;
3623                         *val = n;
3624                         return 1;
3625                 }
3626                 return 0;
3627         }
3628         if (c != '-')
3629                 return 0;
3630         arg++;
3631         eq = strchrnul(arg, '=');
3632         len = eq - arg;
3633         if (!len || strncmp(arg, arg_long, len))
3634                 return 0;
3635         if (*eq) {
3636                 int n;
3637                 char *end;
3638                 if (!isdigit(*++eq))
3639                         return 0;
3640                 n = strtoul(eq, &end, 10);
3641                 if (*end)
3642                         return 0;
3643                 *val = n;
3644         }
3645         return 1;
3646 }
3647
3648 static int diff_scoreopt_parse(const char *opt);
3649
3650 static inline int short_opt(char opt, const char **argv,
3651                             const char **optarg)
3652 {
3653         const char *arg = argv[0];
3654         if (arg[0] != '-' || arg[1] != opt)
3655                 return 0;
3656         if (arg[2] != '\0') {
3657                 *optarg = arg + 2;
3658                 return 1;
3659         }
3660         if (!argv[1])
3661                 die("Option '%c' requires a value", opt);
3662         *optarg = argv[1];
3663         return 2;
3664 }
3665
3666 int parse_long_opt(const char *opt, const char **argv,
3667                    const char **optarg)
3668 {
3669         const char *arg = argv[0];
3670         if (!skip_prefix(arg, "--", &arg))
3671                 return 0;
3672         if (!skip_prefix(arg, opt, &arg))
3673                 return 0;
3674         if (*arg == '=') { /* stuck form: --option=value */
3675                 *optarg = arg + 1;
3676                 return 1;
3677         }
3678         if (*arg != '\0')
3679                 return 0;
3680         /* separate form: --option value */
3681         if (!argv[1])
3682                 die("Option '--%s' requires a value", opt);
3683         *optarg = argv[1];
3684         return 2;
3685 }
3686
3687 static int stat_opt(struct diff_options *options, const char **av)
3688 {
3689         const char *arg = av[0];
3690         char *end;
3691         int width = options->stat_width;
3692         int name_width = options->stat_name_width;
3693         int graph_width = options->stat_graph_width;
3694         int count = options->stat_count;
3695         int argcount = 1;
3696
3697         if (!skip_prefix(arg, "--stat", &arg))
3698                 die("BUG: stat option does not begin with --stat: %s", arg);
3699         end = (char *)arg;
3700
3701         switch (*arg) {
3702         case '-':
3703                 if (skip_prefix(arg, "-width", &arg)) {
3704                         if (*arg == '=')
3705                                 width = strtoul(arg + 1, &end, 10);
3706                         else if (!*arg && !av[1])
3707                                 die_want_option("--stat-width");
3708                         else if (!*arg) {
3709                                 width = strtoul(av[1], &end, 10);
3710                                 argcount = 2;
3711                         }
3712                 } else if (skip_prefix(arg, "-name-width", &arg)) {
3713                         if (*arg == '=')
3714                                 name_width = strtoul(arg + 1, &end, 10);
3715                         else if (!*arg && !av[1])
3716                                 die_want_option("--stat-name-width");
3717                         else if (!*arg) {
3718                                 name_width = strtoul(av[1], &end, 10);
3719                                 argcount = 2;
3720                         }
3721                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
3722                         if (*arg == '=')
3723                                 graph_width = strtoul(arg + 1, &end, 10);
3724                         else if (!*arg && !av[1])
3725                                 die_want_option("--stat-graph-width");
3726                         else if (!*arg) {
3727                                 graph_width = strtoul(av[1], &end, 10);
3728                                 argcount = 2;
3729                         }
3730                 } else if (skip_prefix(arg, "-count", &arg)) {
3731                         if (*arg == '=')
3732                                 count = strtoul(arg + 1, &end, 10);
3733                         else if (!*arg && !av[1])
3734                                 die_want_option("--stat-count");
3735                         else if (!*arg) {
3736                                 count = strtoul(av[1], &end, 10);
3737                                 argcount = 2;
3738                         }
3739                 }
3740                 break;
3741         case '=':
3742                 width = strtoul(arg+1, &end, 10);
3743                 if (*end == ',')
3744                         name_width = strtoul(end+1, &end, 10);
3745                 if (*end == ',')
3746                         count = strtoul(end+1, &end, 10);
3747         }
3748
3749         /* Important! This checks all the error cases! */
3750         if (*end)
3751                 return 0;
3752         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3753         options->stat_name_width = name_width;
3754         options->stat_graph_width = graph_width;
3755         options->stat_width = width;
3756         options->stat_count = count;
3757         return argcount;
3758 }
3759
3760 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3761 {
3762         struct strbuf errmsg = STRBUF_INIT;
3763         if (parse_dirstat_params(options, params, &errmsg))
3764                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3765                     errmsg.buf);
3766         strbuf_release(&errmsg);
3767         /*
3768          * The caller knows a dirstat-related option is given from the command
3769          * line; allow it to say "return this_function();"
3770          */
3771         options->output_format |= DIFF_FORMAT_DIRSTAT;
3772         return 1;
3773 }
3774
3775 static int parse_submodule_opt(struct diff_options *options, const char *value)
3776 {
3777         if (parse_submodule_params(options, value))
3778                 die(_("Failed to parse --submodule option parameter: '%s'"),
3779                         value);
3780         return 1;
3781 }
3782
3783 static const char diff_status_letters[] = {
3784         DIFF_STATUS_ADDED,
3785         DIFF_STATUS_COPIED,
3786         DIFF_STATUS_DELETED,
3787         DIFF_STATUS_MODIFIED,
3788         DIFF_STATUS_RENAMED,
3789         DIFF_STATUS_TYPE_CHANGED,
3790         DIFF_STATUS_UNKNOWN,
3791         DIFF_STATUS_UNMERGED,
3792         DIFF_STATUS_FILTER_AON,
3793         DIFF_STATUS_FILTER_BROKEN,
3794         '\0',
3795 };
3796
3797 static unsigned int filter_bit['Z' + 1];
3798
3799 static void prepare_filter_bits(void)
3800 {
3801         int i;
3802
3803         if (!filter_bit[DIFF_STATUS_ADDED]) {
3804                 for (i = 0; diff_status_letters[i]; i++)
3805                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
3806         }
3807 }
3808
3809 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3810 {
3811         return opt->filter & filter_bit[(int) status];
3812 }
3813
3814 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3815 {
3816         int i, optch;
3817
3818         prepare_filter_bits();
3819
3820         /*
3821          * If there is a negation e.g. 'd' in the input, and we haven't
3822          * initialized the filter field with another --diff-filter, start
3823          * from full set of bits, except for AON.
3824          */
3825         if (!opt->filter) {
3826                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3827                         if (optch < 'a' || 'z' < optch)
3828                                 continue;
3829                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3830                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3831                         break;
3832                 }
3833         }
3834
3835         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3836                 unsigned int bit;
3837                 int negate;
3838
3839                 if ('a' <= optch && optch <= 'z') {
3840                         negate = 1;
3841                         optch = toupper(optch);
3842                 } else {
3843                         negate = 0;
3844                 }
3845
3846                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3847                 if (!bit)
3848                         return optarg[i];
3849                 if (negate)
3850                         opt->filter &= ~bit;
3851                 else
3852                         opt->filter |= bit;
3853         }
3854         return 0;
3855 }
3856
3857 static void enable_patch_output(int *fmt) {
3858         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3859         *fmt |= DIFF_FORMAT_PATCH;
3860 }
3861
3862 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
3863 {
3864         int val = parse_ws_error_highlight(arg);
3865
3866         if (val < 0) {
3867                 error("unknown value after ws-error-highlight=%.*s",
3868                       -1 - val, arg);
3869                 return 0;
3870         }
3871         opt->ws_error_highlight = val;
3872         return 1;
3873 }
3874
3875 int diff_opt_parse(struct diff_options *options,
3876                    const char **av, int ac, const char *prefix)
3877 {
3878         const char *arg = av[0];
3879         const char *optarg;
3880         int argcount;
3881
3882         if (!prefix)
3883                 prefix = "";
3884
3885         /* Output format options */
3886         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3887             || opt_arg(arg, 'U', "unified", &options->context))
3888                 enable_patch_output(&options->output_format);
3889         else if (!strcmp(arg, "--raw"))
3890                 options->output_format |= DIFF_FORMAT_RAW;
3891         else if (!strcmp(arg, "--patch-with-raw")) {
3892                 enable_patch_output(&options->output_format);
3893                 options->output_format |= DIFF_FORMAT_RAW;
3894         } else if (!strcmp(arg, "--numstat"))
3895                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3896         else if (!strcmp(arg, "--shortstat"))
3897                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3898         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3899                 return parse_dirstat_opt(options, "");
3900         else if (skip_prefix(arg, "-X", &arg))
3901                 return parse_dirstat_opt(options, arg);
3902         else if (skip_prefix(arg, "--dirstat=", &arg))
3903                 return parse_dirstat_opt(options, arg);
3904         else if (!strcmp(arg, "--cumulative"))
3905                 return parse_dirstat_opt(options, "cumulative");
3906         else if (!strcmp(arg, "--dirstat-by-file"))
3907                 return parse_dirstat_opt(options, "files");
3908         else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3909                 parse_dirstat_opt(options, "files");
3910                 return parse_dirstat_opt(options, arg);
3911         }
3912         else if (!strcmp(arg, "--check"))
3913                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3914         else if (!strcmp(arg, "--summary"))
3915                 options->output_format |= DIFF_FORMAT_SUMMARY;
3916         else if (!strcmp(arg, "--patch-with-stat")) {
3917                 enable_patch_output(&options->output_format);
3918                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
3919         } else if (!strcmp(arg, "--name-only"))
3920                 options->output_format |= DIFF_FORMAT_NAME;
3921         else if (!strcmp(arg, "--name-status"))
3922                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3923         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3924                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3925         else if (starts_with(arg, "--stat"))
3926                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3927                 return stat_opt(options, av);
3928
3929         /* renames options */
3930         else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3931                  !strcmp(arg, "--break-rewrites")) {
3932                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3933                         return error("invalid argument to -B: %s", arg+2);
3934         }
3935         else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3936                  !strcmp(arg, "--find-renames")) {
3937                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3938                         return error("invalid argument to -M: %s", arg+2);
3939                 options->detect_rename = DIFF_DETECT_RENAME;
3940         }
3941         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3942                 options->irreversible_delete = 1;
3943         }
3944         else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3945                  !strcmp(arg, "--find-copies")) {
3946                 if (options->detect_rename == DIFF_DETECT_COPY)
3947                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3948                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3949                         return error("invalid argument to -C: %s", arg+2);
3950                 options->detect_rename = DIFF_DETECT_COPY;
3951         }
3952         else if (!strcmp(arg, "--no-renames"))
3953                 options->detect_rename = 0;
3954         else if (!strcmp(arg, "--rename-empty"))
3955                 DIFF_OPT_SET(options, RENAME_EMPTY);
3956         else if (!strcmp(arg, "--no-rename-empty"))
3957                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3958         else if (!strcmp(arg, "--relative"))
3959                 DIFF_OPT_SET(options, RELATIVE_NAME);
3960         else if (skip_prefix(arg, "--relative=", &arg)) {
3961                 DIFF_OPT_SET(options, RELATIVE_NAME);
3962                 options->prefix = arg;
3963         }
3964
3965         /* xdiff options */
3966         else if (!strcmp(arg, "--minimal"))
3967                 DIFF_XDL_SET(options, NEED_MINIMAL);
3968         else if (!strcmp(arg, "--no-minimal"))
3969                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3970         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3971                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3972         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3973                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3974         else if (!strcmp(arg, "--ignore-space-at-eol"))
3975                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3976         else if (!strcmp(arg, "--ignore-blank-lines"))
3977                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3978         else if (!strcmp(arg, "--indent-heuristic"))
3979                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
3980         else if (!strcmp(arg, "--no-indent-heuristic"))
3981                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
3982         else if (!strcmp(arg, "--patience"))
3983                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3984         else if (!strcmp(arg, "--histogram"))
3985                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3986         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3987                 long value = parse_algorithm_value(optarg);
3988                 if (value < 0)
3989                         return error("option diff-algorithm accepts \"myers\", "
3990                                      "\"minimal\", \"patience\" and \"histogram\"");
3991                 /* clear out previous settings */
3992                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3993                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3994                 options->xdl_opts |= value;
3995                 return argcount;
3996         }
3997
3998         /* flags options */
3999         else if (!strcmp(arg, "--binary")) {
4000                 enable_patch_output(&options->output_format);
4001                 DIFF_OPT_SET(options, BINARY);
4002         }
4003         else if (!strcmp(arg, "--full-index"))
4004                 DIFF_OPT_SET(options, FULL_INDEX);
4005         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4006                 DIFF_OPT_SET(options, TEXT);
4007         else if (!strcmp(arg, "-R"))
4008                 DIFF_OPT_SET(options, REVERSE_DIFF);
4009         else if (!strcmp(arg, "--find-copies-harder"))
4010                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4011         else if (!strcmp(arg, "--follow"))
4012                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
4013         else if (!strcmp(arg, "--no-follow")) {
4014                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
4015                 DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
4016         } else if (!strcmp(arg, "--color"))
4017                 options->use_color = 1;
4018         else if (skip_prefix(arg, "--color=", &arg)) {
4019                 int value = git_config_colorbool(NULL, arg);
4020                 if (value < 0)
4021                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
4022                 options->use_color = value;
4023         }
4024         else if (!strcmp(arg, "--no-color"))
4025                 options->use_color = 0;
4026         else if (!strcmp(arg, "--color-words")) {
4027                 options->use_color = 1;
4028                 options->word_diff = DIFF_WORDS_COLOR;
4029         }
4030         else if (skip_prefix(arg, "--color-words=", &arg)) {
4031                 options->use_color = 1;
4032                 options->word_diff = DIFF_WORDS_COLOR;
4033                 options->word_regex = arg;
4034         }
4035         else if (!strcmp(arg, "--word-diff")) {
4036                 if (options->word_diff == DIFF_WORDS_NONE)
4037                         options->word_diff = DIFF_WORDS_PLAIN;
4038         }
4039         else if (skip_prefix(arg, "--word-diff=", &arg)) {
4040                 if (!strcmp(arg, "plain"))
4041                         options->word_diff = DIFF_WORDS_PLAIN;
4042                 else if (!strcmp(arg, "color")) {
4043                         options->use_color = 1;
4044                         options->word_diff = DIFF_WORDS_COLOR;
4045                 }
4046                 else if (!strcmp(arg, "porcelain"))
4047                         options->word_diff = DIFF_WORDS_PORCELAIN;
4048                 else if (!strcmp(arg, "none"))
4049                         options->word_diff = DIFF_WORDS_NONE;
4050                 else
4051                         die("bad --word-diff argument: %s", arg);
4052         }
4053         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4054                 if (options->word_diff == DIFF_WORDS_NONE)
4055                         options->word_diff = DIFF_WORDS_PLAIN;
4056                 options->word_regex = optarg;
4057                 return argcount;
4058         }
4059         else if (!strcmp(arg, "--exit-code"))
4060                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4061         else if (!strcmp(arg, "--quiet"))
4062                 DIFF_OPT_SET(options, QUICK);
4063         else if (!strcmp(arg, "--ext-diff"))
4064                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
4065         else if (!strcmp(arg, "--no-ext-diff"))
4066                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
4067         else if (!strcmp(arg, "--textconv"))
4068                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
4069         else if (!strcmp(arg, "--no-textconv"))
4070                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
4071         else if (!strcmp(arg, "--ignore-submodules")) {
4072                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4073                 handle_ignore_submodules_arg(options, "all");
4074         } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
4075                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4076                 handle_ignore_submodules_arg(options, arg);
4077         } else if (!strcmp(arg, "--submodule"))
4078                 options->submodule_format = DIFF_SUBMODULE_LOG;
4079         else if (skip_prefix(arg, "--submodule=", &arg))
4080                 return parse_submodule_opt(options, arg);
4081         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4082                 return parse_ws_error_highlight_opt(options, arg);
4083         else if (!strcmp(arg, "--ita-invisible-in-index"))
4084                 options->ita_invisible_in_index = 1;
4085         else if (!strcmp(arg, "--ita-visible-in-index"))
4086                 options->ita_invisible_in_index = 0;
4087
4088         /* misc options */
4089         else if (!strcmp(arg, "-z"))
4090                 options->line_termination = 0;
4091         else if ((argcount = short_opt('l', av, &optarg))) {
4092                 options->rename_limit = strtoul(optarg, NULL, 10);
4093                 return argcount;
4094         }
4095         else if ((argcount = short_opt('S', av, &optarg))) {
4096                 options->pickaxe = optarg;
4097                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4098                 return argcount;
4099         } else if ((argcount = short_opt('G', av, &optarg))) {
4100                 options->pickaxe = optarg;
4101                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4102                 return argcount;
4103         }
4104         else if (!strcmp(arg, "--pickaxe-all"))
4105                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4106         else if (!strcmp(arg, "--pickaxe-regex"))
4107                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4108         else if ((argcount = short_opt('O', av, &optarg))) {
4109                 options->orderfile = prefix_filename(prefix, optarg);
4110                 return argcount;
4111         }
4112         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4113                 int offending = parse_diff_filter_opt(optarg, options);
4114                 if (offending)
4115                         die("unknown change class '%c' in --diff-filter=%s",
4116                             offending, optarg);
4117                 return argcount;
4118         }
4119         else if (!strcmp(arg, "--no-abbrev"))
4120                 options->abbrev = 0;
4121         else if (!strcmp(arg, "--abbrev"))
4122                 options->abbrev = DEFAULT_ABBREV;
4123         else if (skip_prefix(arg, "--abbrev=", &arg)) {
4124                 options->abbrev = strtoul(arg, NULL, 10);
4125                 if (options->abbrev < MINIMUM_ABBREV)
4126                         options->abbrev = MINIMUM_ABBREV;
4127                 else if (40 < options->abbrev)
4128                         options->abbrev = 40;
4129         }
4130         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4131                 options->a_prefix = optarg;
4132                 return argcount;
4133         }
4134         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4135                 options->line_prefix = optarg;
4136                 options->line_prefix_length = strlen(options->line_prefix);
4137                 graph_setup_line_prefix(options);
4138                 return argcount;
4139         }
4140         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4141                 options->b_prefix = optarg;
4142                 return argcount;
4143         }
4144         else if (!strcmp(arg, "--no-prefix"))
4145                 options->a_prefix = options->b_prefix = "";
4146         else if (opt_arg(arg, '\0', "inter-hunk-context",
4147                          &options->interhunkcontext))
4148                 ;
4149         else if (!strcmp(arg, "-W"))
4150                 DIFF_OPT_SET(options, FUNCCONTEXT);
4151         else if (!strcmp(arg, "--function-context"))
4152                 DIFF_OPT_SET(options, FUNCCONTEXT);
4153         else if (!strcmp(arg, "--no-function-context"))
4154                 DIFF_OPT_CLR(options, FUNCCONTEXT);
4155         else if ((argcount = parse_long_opt("output", av, &optarg))) {
4156                 char *path = prefix_filename(prefix, optarg);
4157                 options->file = xfopen(path, "w");
4158                 options->close_file = 1;
4159                 if (options->use_color != GIT_COLOR_ALWAYS)
4160                         options->use_color = GIT_COLOR_NEVER;
4161                 free(path);
4162                 return argcount;
4163         } else
4164                 return 0;
4165         return 1;
4166 }
4167
4168 int parse_rename_score(const char **cp_p)
4169 {
4170         unsigned long num, scale;
4171         int ch, dot;
4172         const char *cp = *cp_p;
4173
4174         num = 0;
4175         scale = 1;
4176         dot = 0;
4177         for (;;) {
4178                 ch = *cp;
4179                 if ( !dot && ch == '.' ) {
4180                         scale = 1;
4181                         dot = 1;
4182                 } else if ( ch == '%' ) {
4183                         scale = dot ? scale*100 : 100;
4184                         cp++;   /* % is always at the end */
4185                         break;
4186                 } else if ( ch >= '0' && ch <= '9' ) {
4187                         if ( scale < 100000 ) {
4188                                 scale *= 10;
4189                                 num = (num*10) + (ch-'0');
4190                         }
4191                 } else {
4192                         break;
4193                 }
4194                 cp++;
4195         }
4196         *cp_p = cp;
4197
4198         /* user says num divided by scale and we say internally that
4199          * is MAX_SCORE * num / scale.
4200          */
4201         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4202 }
4203
4204 static int diff_scoreopt_parse(const char *opt)
4205 {
4206         int opt1, opt2, cmd;
4207
4208         if (*opt++ != '-')
4209                 return -1;
4210         cmd = *opt++;
4211         if (cmd == '-') {
4212                 /* convert the long-form arguments into short-form versions */
4213                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4214                         if (*opt == 0 || *opt++ == '=')
4215                                 cmd = 'B';
4216                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4217                         if (*opt == 0 || *opt++ == '=')
4218                                 cmd = 'C';
4219                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4220                         if (*opt == 0 || *opt++ == '=')
4221                                 cmd = 'M';
4222                 }
4223         }
4224         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4225                 return -1; /* that is not a -M, -C, or -B option */
4226
4227         opt1 = parse_rename_score(&opt);
4228         if (cmd != 'B')
4229                 opt2 = 0;
4230         else {
4231                 if (*opt == 0)
4232                         opt2 = 0;
4233                 else if (*opt != '/')
4234                         return -1; /* we expect -B80/99 or -B80 */
4235                 else {
4236                         opt++;
4237                         opt2 = parse_rename_score(&opt);
4238                 }
4239         }
4240         if (*opt != 0)
4241                 return -1;
4242         return opt1 | (opt2 << 16);
4243 }
4244
4245 struct diff_queue_struct diff_queued_diff;
4246
4247 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4248 {
4249         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4250         queue->queue[queue->nr++] = dp;
4251 }
4252
4253 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4254                                  struct diff_filespec *one,
4255                                  struct diff_filespec *two)
4256 {
4257         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4258         dp->one = one;
4259         dp->two = two;
4260         if (queue)
4261                 diff_q(queue, dp);
4262         return dp;
4263 }
4264
4265 void diff_free_filepair(struct diff_filepair *p)
4266 {
4267         free_filespec(p->one);
4268         free_filespec(p->two);
4269         free(p);
4270 }
4271
4272 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4273 {
4274         int abblen;
4275         const char *abbrev;
4276
4277         if (len == GIT_SHA1_HEXSZ)
4278                 return oid_to_hex(oid);
4279
4280         abbrev = diff_abbrev_oid(oid, len);
4281         abblen = strlen(abbrev);
4282
4283         /*
4284          * In well-behaved cases, where the abbbreviated result is the
4285          * same as the requested length, append three dots after the
4286          * abbreviation (hence the whole logic is limited to the case
4287          * where abblen < 37); when the actual abbreviated result is a
4288          * bit longer than the requested length, we reduce the number
4289          * of dots so that they match the well-behaved ones.  However,
4290          * if the actual abbreviation is longer than the requested
4291          * length by more than three, we give up on aligning, and add
4292          * three dots anyway, to indicate that the output is not the
4293          * full object name.  Yes, this may be suboptimal, but this
4294          * appears only in "diff --raw --abbrev" output and it is not
4295          * worth the effort to change it now.  Note that this would
4296          * likely to work fine when the automatic sizing of default
4297          * abbreviation length is used--we would be fed -1 in "len" in
4298          * that case, and will end up always appending three-dots, but
4299          * the automatic sizing is supposed to give abblen that ensures
4300          * uniqueness across all objects (statistically speaking).
4301          */
4302         if (abblen < GIT_SHA1_HEXSZ - 3) {
4303                 static char hex[GIT_MAX_HEXSZ + 1];
4304                 if (len < abblen && abblen <= len + 2)
4305                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4306                 else
4307                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4308                 return hex;
4309         }
4310
4311         return oid_to_hex(oid);
4312 }
4313
4314 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4315 {
4316         int line_termination = opt->line_termination;
4317         int inter_name_termination = line_termination ? '\t' : '\0';
4318
4319         fprintf(opt->file, "%s", diff_line_prefix(opt));
4320         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4321                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4322                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4323                 fprintf(opt->file, "%s ",
4324                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4325         }
4326         if (p->score) {
4327                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4328                         inter_name_termination);
4329         } else {
4330                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4331         }
4332
4333         if (p->status == DIFF_STATUS_COPIED ||
4334             p->status == DIFF_STATUS_RENAMED) {
4335                 const char *name_a, *name_b;
4336                 name_a = p->one->path;
4337                 name_b = p->two->path;
4338                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4339                 write_name_quoted(name_a, opt->file, inter_name_termination);
4340                 write_name_quoted(name_b, opt->file, line_termination);
4341         } else {
4342                 const char *name_a, *name_b;
4343                 name_a = p->one->mode ? p->one->path : p->two->path;
4344                 name_b = NULL;
4345                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4346                 write_name_quoted(name_a, opt->file, line_termination);
4347         }
4348 }
4349
4350 int diff_unmodified_pair(struct diff_filepair *p)
4351 {
4352         /* This function is written stricter than necessary to support
4353          * the currently implemented transformers, but the idea is to
4354          * let transformers to produce diff_filepairs any way they want,
4355          * and filter and clean them up here before producing the output.
4356          */
4357         struct diff_filespec *one = p->one, *two = p->two;
4358
4359         if (DIFF_PAIR_UNMERGED(p))
4360                 return 0; /* unmerged is interesting */
4361
4362         /* deletion, addition, mode or type change
4363          * and rename are all interesting.
4364          */
4365         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4366             DIFF_PAIR_MODE_CHANGED(p) ||
4367             strcmp(one->path, two->path))
4368                 return 0;
4369
4370         /* both are valid and point at the same path.  that is, we are
4371          * dealing with a change.
4372          */
4373         if (one->oid_valid && two->oid_valid &&
4374             !oidcmp(&one->oid, &two->oid) &&
4375             !one->dirty_submodule && !two->dirty_submodule)
4376                 return 1; /* no change */
4377         if (!one->oid_valid && !two->oid_valid)
4378                 return 1; /* both look at the same file on the filesystem. */
4379         return 0;
4380 }
4381
4382 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4383 {
4384         if (diff_unmodified_pair(p))
4385                 return;
4386
4387         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4388             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4389                 return; /* no tree diffs in patch format */
4390
4391         run_diff(p, o);
4392 }
4393
4394 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4395                             struct diffstat_t *diffstat)
4396 {
4397         if (diff_unmodified_pair(p))
4398                 return;
4399
4400         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4401             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4402                 return; /* no useful stat for tree diffs */
4403
4404         run_diffstat(p, o, diffstat);
4405 }
4406
4407 static void diff_flush_checkdiff(struct diff_filepair *p,
4408                 struct diff_options *o)
4409 {
4410         if (diff_unmodified_pair(p))
4411                 return;
4412
4413         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4414             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4415                 return; /* nothing to check in tree diffs */
4416
4417         run_checkdiff(p, o);
4418 }
4419
4420 int diff_queue_is_empty(void)
4421 {
4422         struct diff_queue_struct *q = &diff_queued_diff;
4423         int i;
4424         for (i = 0; i < q->nr; i++)
4425                 if (!diff_unmodified_pair(q->queue[i]))
4426                         return 0;
4427         return 1;
4428 }
4429
4430 #if DIFF_DEBUG
4431 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4432 {
4433         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4434                 x, one ? one : "",
4435                 s->path,
4436                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4437                 s->mode,
4438                 s->oid_valid ? oid_to_hex(&s->oid) : "");
4439         fprintf(stderr, "queue[%d] %s size %lu\n",
4440                 x, one ? one : "",
4441                 s->size);
4442 }
4443
4444 void diff_debug_filepair(const struct diff_filepair *p, int i)
4445 {
4446         diff_debug_filespec(p->one, i, "one");
4447         diff_debug_filespec(p->two, i, "two");
4448         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4449                 p->score, p->status ? p->status : '?',
4450                 p->one->rename_used, p->broken_pair);
4451 }
4452
4453 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4454 {
4455         int i;
4456         if (msg)
4457                 fprintf(stderr, "%s\n", msg);
4458         fprintf(stderr, "q->nr = %d\n", q->nr);
4459         for (i = 0; i < q->nr; i++) {
4460                 struct diff_filepair *p = q->queue[i];
4461                 diff_debug_filepair(p, i);
4462         }
4463 }
4464 #endif
4465
4466 static void diff_resolve_rename_copy(void)
4467 {
4468         int i;
4469         struct diff_filepair *p;
4470         struct diff_queue_struct *q = &diff_queued_diff;
4471
4472         diff_debug_queue("resolve-rename-copy", q);
4473
4474         for (i = 0; i < q->nr; i++) {
4475                 p = q->queue[i];
4476                 p->status = 0; /* undecided */
4477                 if (DIFF_PAIR_UNMERGED(p))
4478                         p->status = DIFF_STATUS_UNMERGED;
4479                 else if (!DIFF_FILE_VALID(p->one))
4480                         p->status = DIFF_STATUS_ADDED;
4481                 else if (!DIFF_FILE_VALID(p->two))
4482                         p->status = DIFF_STATUS_DELETED;
4483                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4484                         p->status = DIFF_STATUS_TYPE_CHANGED;
4485
4486                 /* from this point on, we are dealing with a pair
4487                  * whose both sides are valid and of the same type, i.e.
4488                  * either in-place edit or rename/copy edit.
4489                  */
4490                 else if (DIFF_PAIR_RENAME(p)) {
4491                         /*
4492                          * A rename might have re-connected a broken
4493                          * pair up, causing the pathnames to be the
4494                          * same again. If so, that's not a rename at
4495                          * all, just a modification..
4496                          *
4497                          * Otherwise, see if this source was used for
4498                          * multiple renames, in which case we decrement
4499                          * the count, and call it a copy.
4500                          */
4501                         if (!strcmp(p->one->path, p->two->path))
4502                                 p->status = DIFF_STATUS_MODIFIED;
4503                         else if (--p->one->rename_used > 0)
4504                                 p->status = DIFF_STATUS_COPIED;
4505                         else
4506                                 p->status = DIFF_STATUS_RENAMED;
4507                 }
4508                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
4509                          p->one->mode != p->two->mode ||
4510                          p->one->dirty_submodule ||
4511                          p->two->dirty_submodule ||
4512                          is_null_oid(&p->one->oid))
4513                         p->status = DIFF_STATUS_MODIFIED;
4514                 else {
4515                         /* This is a "no-change" entry and should not
4516                          * happen anymore, but prepare for broken callers.
4517                          */
4518                         error("feeding unmodified %s to diffcore",
4519                               p->one->path);
4520                         p->status = DIFF_STATUS_UNKNOWN;
4521                 }
4522         }
4523         diff_debug_queue("resolve-rename-copy done", q);
4524 }
4525
4526 static int check_pair_status(struct diff_filepair *p)
4527 {
4528         switch (p->status) {
4529         case DIFF_STATUS_UNKNOWN:
4530                 return 0;
4531         case 0:
4532                 die("internal error in diff-resolve-rename-copy");
4533         default:
4534                 return 1;
4535         }
4536 }
4537
4538 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4539 {
4540         int fmt = opt->output_format;
4541
4542         if (fmt & DIFF_FORMAT_CHECKDIFF)
4543                 diff_flush_checkdiff(p, opt);
4544         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4545                 diff_flush_raw(p, opt);
4546         else if (fmt & DIFF_FORMAT_NAME) {
4547                 const char *name_a, *name_b;
4548                 name_a = p->two->path;
4549                 name_b = NULL;
4550                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4551                 fprintf(opt->file, "%s", diff_line_prefix(opt));
4552                 write_name_quoted(name_a, opt->file, opt->line_termination);
4553         }
4554 }
4555
4556 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4557 {
4558         if (fs->mode)
4559                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4560         else
4561                 fprintf(file, " %s ", newdelete);
4562         write_name_quoted(fs->path, file, '\n');
4563 }
4564
4565
4566 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4567                 const char *line_prefix)
4568 {
4569         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4570                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4571                         p->two->mode, show_name ? ' ' : '\n');
4572                 if (show_name) {
4573                         write_name_quoted(p->two->path, file, '\n');
4574                 }
4575         }
4576 }
4577
4578 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4579                         const char *line_prefix)
4580 {
4581         char *names = pprint_rename(p->one->path, p->two->path);
4582
4583         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4584         free(names);
4585         show_mode_change(file, p, 0, line_prefix);
4586 }
4587
4588 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4589 {
4590         FILE *file = opt->file;
4591         const char *line_prefix = diff_line_prefix(opt);
4592
4593         switch(p->status) {
4594         case DIFF_STATUS_DELETED:
4595                 fputs(line_prefix, file);
4596                 show_file_mode_name(file, "delete", p->one);
4597                 break;
4598         case DIFF_STATUS_ADDED:
4599                 fputs(line_prefix, file);
4600                 show_file_mode_name(file, "create", p->two);
4601                 break;
4602         case DIFF_STATUS_COPIED:
4603                 fputs(line_prefix, file);
4604                 show_rename_copy(file, "copy", p, line_prefix);
4605                 break;
4606         case DIFF_STATUS_RENAMED:
4607                 fputs(line_prefix, file);
4608                 show_rename_copy(file, "rename", p, line_prefix);
4609                 break;
4610         default:
4611                 if (p->score) {
4612                         fprintf(file, "%s rewrite ", line_prefix);
4613                         write_name_quoted(p->two->path, file, ' ');
4614                         fprintf(file, "(%d%%)\n", similarity_index(p));
4615                 }
4616                 show_mode_change(file, p, !p->score, line_prefix);
4617                 break;
4618         }
4619 }
4620
4621 struct patch_id_t {
4622         git_SHA_CTX *ctx;
4623         int patchlen;
4624 };
4625
4626 static int remove_space(char *line, int len)
4627 {
4628         int i;
4629         char *dst = line;
4630         unsigned char c;
4631
4632         for (i = 0; i < len; i++)
4633                 if (!isspace((c = line[i])))
4634                         *dst++ = c;
4635
4636         return dst - line;
4637 }
4638
4639 static void patch_id_consume(void *priv, char *line, unsigned long len)
4640 {
4641         struct patch_id_t *data = priv;
4642         int new_len;
4643
4644         /* Ignore line numbers when computing the SHA1 of the patch */
4645         if (starts_with(line, "@@ -"))
4646                 return;
4647
4648         new_len = remove_space(line, len);
4649
4650         git_SHA1_Update(data->ctx, line, new_len);
4651         data->patchlen += new_len;
4652 }
4653
4654 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
4655 {
4656         git_SHA1_Update(ctx, str, strlen(str));
4657 }
4658
4659 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
4660 {
4661         /* large enough for 2^32 in octal */
4662         char buf[12];
4663         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
4664         git_SHA1_Update(ctx, buf, len);
4665 }
4666
4667 /* returns 0 upon success, and writes result into sha1 */
4668 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4669 {
4670         struct diff_queue_struct *q = &diff_queued_diff;
4671         int i;
4672         git_SHA_CTX ctx;
4673         struct patch_id_t data;
4674
4675         git_SHA1_Init(&ctx);
4676         memset(&data, 0, sizeof(struct patch_id_t));
4677         data.ctx = &ctx;
4678
4679         for (i = 0; i < q->nr; i++) {
4680                 xpparam_t xpp;
4681                 xdemitconf_t xecfg;
4682                 mmfile_t mf1, mf2;
4683                 struct diff_filepair *p = q->queue[i];
4684                 int len1, len2;
4685
4686                 memset(&xpp, 0, sizeof(xpp));
4687                 memset(&xecfg, 0, sizeof(xecfg));
4688                 if (p->status == 0)
4689                         return error("internal diff status error");
4690                 if (p->status == DIFF_STATUS_UNKNOWN)
4691                         continue;
4692                 if (diff_unmodified_pair(p))
4693                         continue;
4694                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4695                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4696                         continue;
4697                 if (DIFF_PAIR_UNMERGED(p))
4698                         continue;
4699
4700                 diff_fill_oid_info(p->one);
4701                 diff_fill_oid_info(p->two);
4702
4703                 len1 = remove_space(p->one->path, strlen(p->one->path));
4704                 len2 = remove_space(p->two->path, strlen(p->two->path));
4705                 patch_id_add_string(&ctx, "diff--git");
4706                 patch_id_add_string(&ctx, "a/");
4707                 git_SHA1_Update(&ctx, p->one->path, len1);
4708                 patch_id_add_string(&ctx, "b/");
4709                 git_SHA1_Update(&ctx, p->two->path, len2);
4710
4711                 if (p->one->mode == 0) {
4712                         patch_id_add_string(&ctx, "newfilemode");
4713                         patch_id_add_mode(&ctx, p->two->mode);
4714                         patch_id_add_string(&ctx, "---/dev/null");
4715                         patch_id_add_string(&ctx, "+++b/");
4716                         git_SHA1_Update(&ctx, p->two->path, len2);
4717                 } else if (p->two->mode == 0) {
4718                         patch_id_add_string(&ctx, "deletedfilemode");
4719                         patch_id_add_mode(&ctx, p->one->mode);
4720                         patch_id_add_string(&ctx, "---a/");
4721                         git_SHA1_Update(&ctx, p->one->path, len1);
4722                         patch_id_add_string(&ctx, "+++/dev/null");
4723                 } else {
4724                         patch_id_add_string(&ctx, "---a/");
4725                         git_SHA1_Update(&ctx, p->one->path, len1);
4726                         patch_id_add_string(&ctx, "+++b/");
4727                         git_SHA1_Update(&ctx, p->two->path, len2);
4728                 }
4729
4730                 if (diff_header_only)
4731                         continue;
4732
4733                 if (fill_mmfile(&mf1, p->one) < 0 ||
4734                     fill_mmfile(&mf2, p->two) < 0)
4735                         return error("unable to read files to diff");
4736
4737                 if (diff_filespec_is_binary(p->one) ||
4738                     diff_filespec_is_binary(p->two)) {
4739                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4740                                         GIT_SHA1_HEXSZ);
4741                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4742                                         GIT_SHA1_HEXSZ);
4743                         continue;
4744                 }
4745
4746                 xpp.flags = 0;
4747                 xecfg.ctxlen = 3;
4748                 xecfg.flags = 0;
4749                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4750                                   &xpp, &xecfg))
4751                         return error("unable to generate patch-id diff for %s",
4752                                      p->one->path);
4753         }
4754
4755         git_SHA1_Final(oid->hash, &ctx);
4756         return 0;
4757 }
4758
4759 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4760 {
4761         struct diff_queue_struct *q = &diff_queued_diff;
4762         int i;
4763         int result = diff_get_patch_id(options, oid, diff_header_only);
4764
4765         for (i = 0; i < q->nr; i++)
4766                 diff_free_filepair(q->queue[i]);
4767
4768         free(q->queue);
4769         DIFF_QUEUE_CLEAR(q);
4770
4771         return result;
4772 }
4773
4774 static int is_summary_empty(const struct diff_queue_struct *q)
4775 {
4776         int i;
4777
4778         for (i = 0; i < q->nr; i++) {
4779                 const struct diff_filepair *p = q->queue[i];
4780
4781                 switch (p->status) {
4782                 case DIFF_STATUS_DELETED:
4783                 case DIFF_STATUS_ADDED:
4784                 case DIFF_STATUS_COPIED:
4785                 case DIFF_STATUS_RENAMED:
4786                         return 0;
4787                 default:
4788                         if (p->score)
4789                                 return 0;
4790                         if (p->one->mode && p->two->mode &&
4791                             p->one->mode != p->two->mode)
4792                                 return 0;
4793                         break;
4794                 }
4795         }
4796         return 1;
4797 }
4798
4799 static const char rename_limit_warning[] =
4800 N_("inexact rename detection was skipped due to too many files.");
4801
4802 static const char degrade_cc_to_c_warning[] =
4803 N_("only found copies from modified paths due to too many files.");
4804
4805 static const char rename_limit_advice[] =
4806 N_("you may want to set your %s variable to at least "
4807    "%d and retry the command.");
4808
4809 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4810 {
4811         if (degraded_cc)
4812                 warning(_(degrade_cc_to_c_warning));
4813         else if (needed)
4814                 warning(_(rename_limit_warning));
4815         else
4816                 return;
4817         if (0 < needed && needed < 32767)
4818                 warning(_(rename_limit_advice), varname, needed);
4819 }
4820
4821 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
4822 {
4823         int i;
4824         struct diff_queue_struct *q = &diff_queued_diff;
4825
4826         if (WSEH_NEW & WS_RULE_MASK)
4827                 die("BUG: WS rules bit mask overlaps with diff symbol flags");
4828
4829         for (i = 0; i < q->nr; i++) {
4830                 struct diff_filepair *p = q->queue[i];
4831                 if (check_pair_status(p))
4832                         diff_flush_patch(p, o);
4833         }
4834 }
4835
4836 void diff_flush(struct diff_options *options)
4837 {
4838         struct diff_queue_struct *q = &diff_queued_diff;
4839         int i, output_format = options->output_format;
4840         int separator = 0;
4841         int dirstat_by_line = 0;
4842
4843         /*
4844          * Order: raw, stat, summary, patch
4845          * or:    name/name-status/checkdiff (other bits clear)
4846          */
4847         if (!q->nr)
4848                 goto free_queue;
4849
4850         if (output_format & (DIFF_FORMAT_RAW |
4851                              DIFF_FORMAT_NAME |
4852                              DIFF_FORMAT_NAME_STATUS |
4853                              DIFF_FORMAT_CHECKDIFF)) {
4854                 for (i = 0; i < q->nr; i++) {
4855                         struct diff_filepair *p = q->queue[i];
4856                         if (check_pair_status(p))
4857                                 flush_one_pair(p, options);
4858                 }
4859                 separator++;
4860         }
4861
4862         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4863                 dirstat_by_line = 1;
4864
4865         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4866             dirstat_by_line) {
4867                 struct diffstat_t diffstat;
4868
4869                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4870                 for (i = 0; i < q->nr; i++) {
4871                         struct diff_filepair *p = q->queue[i];
4872                         if (check_pair_status(p))
4873                                 diff_flush_stat(p, options, &diffstat);
4874                 }
4875                 if (output_format & DIFF_FORMAT_NUMSTAT)
4876                         show_numstat(&diffstat, options);
4877                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4878                         show_stats(&diffstat, options);
4879                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4880                         show_shortstats(&diffstat, options);
4881                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4882                         show_dirstat_by_line(&diffstat, options);
4883                 free_diffstat_info(&diffstat);
4884                 separator++;
4885         }
4886         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4887                 show_dirstat(options);
4888
4889         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4890                 for (i = 0; i < q->nr; i++) {
4891                         diff_summary(options, q->queue[i]);
4892                 }
4893                 separator++;
4894         }
4895
4896         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4897             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4898             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4899                 /*
4900                  * run diff_flush_patch for the exit status. setting
4901                  * options->file to /dev/null should be safe, because we
4902                  * aren't supposed to produce any output anyway.
4903                  */
4904                 if (options->close_file)
4905                         fclose(options->file);
4906                 options->file = xfopen("/dev/null", "w");
4907                 options->close_file = 1;
4908                 for (i = 0; i < q->nr; i++) {
4909                         struct diff_filepair *p = q->queue[i];
4910                         if (check_pair_status(p))
4911                                 diff_flush_patch(p, options);
4912                         if (options->found_changes)
4913                                 break;
4914                 }
4915         }
4916
4917         if (output_format & DIFF_FORMAT_PATCH) {
4918                 if (separator) {
4919                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
4920                         if (options->stat_sep) {
4921                                 /* attach patch instead of inline */
4922                                 fputs(options->stat_sep, options->file);
4923                         }
4924                 }
4925
4926                 diff_flush_patch_all_file_pairs(options);
4927         }
4928
4929         if (output_format & DIFF_FORMAT_CALLBACK)
4930                 options->format_callback(q, options, options->format_callback_data);
4931
4932         for (i = 0; i < q->nr; i++)
4933                 diff_free_filepair(q->queue[i]);
4934 free_queue:
4935         free(q->queue);
4936         DIFF_QUEUE_CLEAR(q);
4937         if (options->close_file)
4938                 fclose(options->file);
4939
4940         /*
4941          * Report the content-level differences with HAS_CHANGES;
4942          * diff_addremove/diff_change does not set the bit when
4943          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4944          */
4945         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4946                 if (options->found_changes)
4947                         DIFF_OPT_SET(options, HAS_CHANGES);
4948                 else
4949                         DIFF_OPT_CLR(options, HAS_CHANGES);
4950         }
4951 }
4952
4953 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4954 {
4955         return (((p->status == DIFF_STATUS_MODIFIED) &&
4956                  ((p->score &&
4957                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4958                   (!p->score &&
4959                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4960                 ((p->status != DIFF_STATUS_MODIFIED) &&
4961                  filter_bit_tst(p->status, options)));
4962 }
4963
4964 static void diffcore_apply_filter(struct diff_options *options)
4965 {
4966         int i;
4967         struct diff_queue_struct *q = &diff_queued_diff;
4968         struct diff_queue_struct outq;
4969
4970         DIFF_QUEUE_CLEAR(&outq);
4971
4972         if (!options->filter)
4973                 return;
4974
4975         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4976                 int found;
4977                 for (i = found = 0; !found && i < q->nr; i++) {
4978                         if (match_filter(options, q->queue[i]))
4979                                 found++;
4980                 }
4981                 if (found)
4982                         return;
4983
4984                 /* otherwise we will clear the whole queue
4985                  * by copying the empty outq at the end of this
4986                  * function, but first clear the current entries
4987                  * in the queue.
4988                  */
4989                 for (i = 0; i < q->nr; i++)
4990                         diff_free_filepair(q->queue[i]);
4991         }
4992         else {
4993                 /* Only the matching ones */
4994                 for (i = 0; i < q->nr; i++) {
4995                         struct diff_filepair *p = q->queue[i];
4996                         if (match_filter(options, p))
4997                                 diff_q(&outq, p);
4998                         else
4999                                 diff_free_filepair(p);
5000                 }
5001         }
5002         free(q->queue);
5003         *q = outq;
5004 }
5005
5006 /* Check whether two filespecs with the same mode and size are identical */
5007 static int diff_filespec_is_identical(struct diff_filespec *one,
5008                                       struct diff_filespec *two)
5009 {
5010         if (S_ISGITLINK(one->mode))
5011                 return 0;
5012         if (diff_populate_filespec(one, 0))
5013                 return 0;
5014         if (diff_populate_filespec(two, 0))
5015                 return 0;
5016         return !memcmp(one->data, two->data, one->size);
5017 }
5018
5019 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5020 {
5021         if (p->done_skip_stat_unmatch)
5022                 return p->skip_stat_unmatch_result;
5023
5024         p->done_skip_stat_unmatch = 1;
5025         p->skip_stat_unmatch_result = 0;
5026         /*
5027          * 1. Entries that come from stat info dirtiness
5028          *    always have both sides (iow, not create/delete),
5029          *    one side of the object name is unknown, with
5030          *    the same mode and size.  Keep the ones that
5031          *    do not match these criteria.  They have real
5032          *    differences.
5033          *
5034          * 2. At this point, the file is known to be modified,
5035          *    with the same mode and size, and the object
5036          *    name of one side is unknown.  Need to inspect
5037          *    the identical contents.
5038          */
5039         if (!DIFF_FILE_VALID(p->one) || /* (1) */
5040             !DIFF_FILE_VALID(p->two) ||
5041             (p->one->oid_valid && p->two->oid_valid) ||
5042             (p->one->mode != p->two->mode) ||
5043             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5044             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5045             (p->one->size != p->two->size) ||
5046             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5047                 p->skip_stat_unmatch_result = 1;
5048         return p->skip_stat_unmatch_result;
5049 }
5050
5051 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5052 {
5053         int i;
5054         struct diff_queue_struct *q = &diff_queued_diff;
5055         struct diff_queue_struct outq;
5056         DIFF_QUEUE_CLEAR(&outq);
5057
5058         for (i = 0; i < q->nr; i++) {
5059                 struct diff_filepair *p = q->queue[i];
5060
5061                 if (diff_filespec_check_stat_unmatch(p))
5062                         diff_q(&outq, p);
5063                 else {
5064                         /*
5065                          * The caller can subtract 1 from skip_stat_unmatch
5066                          * to determine how many paths were dirty only
5067                          * due to stat info mismatch.
5068                          */
5069                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
5070                                 diffopt->skip_stat_unmatch++;
5071                         diff_free_filepair(p);
5072                 }
5073         }
5074         free(q->queue);
5075         *q = outq;
5076 }
5077
5078 static int diffnamecmp(const void *a_, const void *b_)
5079 {
5080         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5081         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5082         const char *name_a, *name_b;
5083
5084         name_a = a->one ? a->one->path : a->two->path;
5085         name_b = b->one ? b->one->path : b->two->path;
5086         return strcmp(name_a, name_b);
5087 }
5088
5089 void diffcore_fix_diff_index(struct diff_options *options)
5090 {
5091         struct diff_queue_struct *q = &diff_queued_diff;
5092         QSORT(q->queue, q->nr, diffnamecmp);
5093 }
5094
5095 void diffcore_std(struct diff_options *options)
5096 {
5097         /* NOTE please keep the following in sync with diff_tree_combined() */
5098         if (options->skip_stat_unmatch)
5099                 diffcore_skip_stat_unmatch(options);
5100         if (!options->found_follow) {
5101                 /* See try_to_follow_renames() in tree-diff.c */
5102                 if (options->break_opt != -1)
5103                         diffcore_break(options->break_opt);
5104                 if (options->detect_rename)
5105                         diffcore_rename(options);
5106                 if (options->break_opt != -1)
5107                         diffcore_merge_broken();
5108         }
5109         if (options->pickaxe)
5110                 diffcore_pickaxe(options);
5111         if (options->orderfile)
5112                 diffcore_order(options->orderfile);
5113         if (!options->found_follow)
5114                 /* See try_to_follow_renames() in tree-diff.c */
5115                 diff_resolve_rename_copy();
5116         diffcore_apply_filter(options);
5117
5118         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5119                 DIFF_OPT_SET(options, HAS_CHANGES);
5120         else
5121                 DIFF_OPT_CLR(options, HAS_CHANGES);
5122
5123         options->found_follow = 0;
5124 }
5125
5126 int diff_result_code(struct diff_options *opt, int status)
5127 {
5128         int result = 0;
5129
5130         diff_warn_rename_limit("diff.renameLimit",
5131                                opt->needed_rename_limit,
5132                                opt->degraded_cc_to_c);
5133         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5134             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5135                 return status;
5136         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5137             DIFF_OPT_TST(opt, HAS_CHANGES))
5138                 result |= 01;
5139         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5140             DIFF_OPT_TST(opt, CHECK_FAILED))
5141                 result |= 02;
5142         return result;
5143 }
5144
5145 int diff_can_quit_early(struct diff_options *opt)
5146 {
5147         return (DIFF_OPT_TST(opt, QUICK) &&
5148                 !opt->filter &&
5149                 DIFF_OPT_TST(opt, HAS_CHANGES));
5150 }
5151
5152 /*
5153  * Shall changes to this submodule be ignored?
5154  *
5155  * Submodule changes can be configured to be ignored separately for each path,
5156  * but that configuration can be overridden from the command line.
5157  */
5158 static int is_submodule_ignored(const char *path, struct diff_options *options)
5159 {
5160         int ignored = 0;
5161         unsigned orig_flags = options->flags;
5162         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5163                 set_diffopt_flags_from_submodule_config(options, path);
5164         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5165                 ignored = 1;
5166         options->flags = orig_flags;
5167         return ignored;
5168 }
5169
5170 void diff_addremove(struct diff_options *options,
5171                     int addremove, unsigned mode,
5172                     const struct object_id *oid,
5173                     int oid_valid,
5174                     const char *concatpath, unsigned dirty_submodule)
5175 {
5176         struct diff_filespec *one, *two;
5177
5178         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5179                 return;
5180
5181         /* This may look odd, but it is a preparation for
5182          * feeding "there are unchanged files which should
5183          * not produce diffs, but when you are doing copy
5184          * detection you would need them, so here they are"
5185          * entries to the diff-core.  They will be prefixed
5186          * with something like '=' or '*' (I haven't decided
5187          * which but should not make any difference).
5188          * Feeding the same new and old to diff_change()
5189          * also has the same effect.
5190          * Before the final output happens, they are pruned after
5191          * merged into rename/copy pairs as appropriate.
5192          */
5193         if (DIFF_OPT_TST(options, REVERSE_DIFF))
5194                 addremove = (addremove == '+' ? '-' :
5195                              addremove == '-' ? '+' : addremove);
5196
5197         if (options->prefix &&
5198             strncmp(concatpath, options->prefix, options->prefix_length))
5199                 return;
5200
5201         one = alloc_filespec(concatpath);
5202         two = alloc_filespec(concatpath);
5203
5204         if (addremove != '+')
5205                 fill_filespec(one, oid, oid_valid, mode);
5206         if (addremove != '-') {
5207                 fill_filespec(two, oid, oid_valid, mode);
5208                 two->dirty_submodule = dirty_submodule;
5209         }
5210
5211         diff_queue(&diff_queued_diff, one, two);
5212         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5213                 DIFF_OPT_SET(options, HAS_CHANGES);
5214 }
5215
5216 void diff_change(struct diff_options *options,
5217                  unsigned old_mode, unsigned new_mode,
5218                  const struct object_id *old_oid,
5219                  const struct object_id *new_oid,
5220                  int old_oid_valid, int new_oid_valid,
5221                  const char *concatpath,
5222                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5223 {
5224         struct diff_filespec *one, *two;
5225         struct diff_filepair *p;
5226
5227         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5228             is_submodule_ignored(concatpath, options))
5229                 return;
5230
5231         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5232                 SWAP(old_mode, new_mode);
5233                 SWAP(old_oid, new_oid);
5234                 SWAP(old_oid_valid, new_oid_valid);
5235                 SWAP(old_dirty_submodule, new_dirty_submodule);
5236         }
5237
5238         if (options->prefix &&
5239             strncmp(concatpath, options->prefix, options->prefix_length))
5240                 return;
5241
5242         one = alloc_filespec(concatpath);
5243         two = alloc_filespec(concatpath);
5244         fill_filespec(one, old_oid, old_oid_valid, old_mode);
5245         fill_filespec(two, new_oid, new_oid_valid, new_mode);
5246         one->dirty_submodule = old_dirty_submodule;
5247         two->dirty_submodule = new_dirty_submodule;
5248         p = diff_queue(&diff_queued_diff, one, two);
5249
5250         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5251                 return;
5252
5253         if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5254             !diff_filespec_check_stat_unmatch(p))
5255                 return;
5256
5257         DIFF_OPT_SET(options, HAS_CHANGES);
5258 }
5259
5260 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5261 {
5262         struct diff_filepair *pair;
5263         struct diff_filespec *one, *two;
5264
5265         if (options->prefix &&
5266             strncmp(path, options->prefix, options->prefix_length))
5267                 return NULL;
5268
5269         one = alloc_filespec(path);
5270         two = alloc_filespec(path);
5271         pair = diff_queue(&diff_queued_diff, one, two);
5272         pair->is_unmerged = 1;
5273         return pair;
5274 }
5275
5276 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5277                 size_t *outsize)
5278 {
5279         struct diff_tempfile *temp;
5280         const char *argv[3];
5281         const char **arg = argv;
5282         struct child_process child = CHILD_PROCESS_INIT;
5283         struct strbuf buf = STRBUF_INIT;
5284         int err = 0;
5285
5286         temp = prepare_temp_file(spec->path, spec);
5287         *arg++ = pgm;
5288         *arg++ = temp->name;
5289         *arg = NULL;
5290
5291         child.use_shell = 1;
5292         child.argv = argv;
5293         child.out = -1;
5294         if (start_command(&child)) {
5295                 remove_tempfile();
5296                 return NULL;
5297         }
5298
5299         if (strbuf_read(&buf, child.out, 0) < 0)
5300                 err = error("error reading from textconv command '%s'", pgm);
5301         close(child.out);
5302
5303         if (finish_command(&child) || err) {
5304                 strbuf_release(&buf);
5305                 remove_tempfile();
5306                 return NULL;
5307         }
5308         remove_tempfile();
5309
5310         return strbuf_detach(&buf, outsize);
5311 }
5312
5313 size_t fill_textconv(struct userdiff_driver *driver,
5314                      struct diff_filespec *df,
5315                      char **outbuf)
5316 {
5317         size_t size;
5318
5319         if (!driver) {
5320                 if (!DIFF_FILE_VALID(df)) {
5321                         *outbuf = "";
5322                         return 0;
5323                 }
5324                 if (diff_populate_filespec(df, 0))
5325                         die("unable to read files to diff");
5326                 *outbuf = df->data;
5327                 return df->size;
5328         }
5329
5330         if (!driver->textconv)
5331                 die("BUG: fill_textconv called with non-textconv driver");
5332
5333         if (driver->textconv_cache && df->oid_valid) {
5334                 *outbuf = notes_cache_get(driver->textconv_cache,
5335                                           &df->oid,
5336                                           &size);
5337                 if (*outbuf)
5338                         return size;
5339         }
5340
5341         *outbuf = run_textconv(driver->textconv, df, &size);
5342         if (!*outbuf)
5343                 die("unable to read files to diff");
5344
5345         if (driver->textconv_cache && df->oid_valid) {
5346                 /* ignore errors, as we might be in a readonly repository */
5347                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
5348                                 size);
5349                 /*
5350                  * we could save up changes and flush them all at the end,
5351                  * but we would need an extra call after all diffing is done.
5352                  * Since generating a cache entry is the slow path anyway,
5353                  * this extra overhead probably isn't a big deal.
5354                  */
5355                 notes_cache_write(driver->textconv_cache);
5356         }
5357
5358         return size;
5359 }
5360
5361 int textconv_object(const char *path,
5362                     unsigned mode,
5363                     const struct object_id *oid,
5364                     int oid_valid,
5365                     char **buf,
5366                     unsigned long *buf_size)
5367 {
5368         struct diff_filespec *df;
5369         struct userdiff_driver *textconv;
5370
5371         df = alloc_filespec(path);
5372         fill_filespec(df, oid, oid_valid, mode);
5373         textconv = get_textconv(df);
5374         if (!textconv) {
5375                 free_filespec(df);
5376                 return 0;
5377         }
5378
5379         *buf_size = fill_textconv(textconv, df, buf);
5380         free_filespec(df);
5381         return 1;
5382 }
5383
5384 void setup_diff_pager(struct diff_options *opt)
5385 {
5386         /*
5387          * If the user asked for our exit code, then either they want --quiet
5388          * or --exit-code. We should definitely not bother with a pager in the
5389          * former case, as we will generate no output. Since we still properly
5390          * report our exit code even when a pager is run, we _could_ run a
5391          * pager with --exit-code. But since we have not done so historically,
5392          * and because it is easy to find people oneline advising "git diff
5393          * --exit-code" in hooks and other scripts, we do not do so.
5394          */
5395         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5396             check_pager_config("diff") != 0)
5397                 setup_pager();
5398 }