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

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "delta.h"
   9 #include "xdiff-interface.h"
  10 #include "color.h"
  11 #include "attr.h"
  12 #include "run-command.h"
  13 #include "utf8.h"
  14 #include "userdiff.h"
  15 #include "sigchain.h"
  16 #include "submodule.h"
  17 #include "ll-merge.h"
  18 #include "string-list.h"
  19
  20 #ifdef NO_FAST_WORKING_DIRECTORY
  21 #define FAST_WORKING_DIRECTORY 0
  22 #else
  23 #define FAST_WORKING_DIRECTORY 1
  24 #endif
  25
  26 static int diff_detect_rename_default;
  27 static int diff_rename_limit_default = 400;
  28 static int diff_suppress_blank_empty;
  29 static int diff_use_color_default = -1;
  30 static int diff_context_default = 3;
  31 static const char *diff_word_regex_cfg;
  32 static const char *external_diff_cmd_cfg;
  33 int diff_auto_refresh_index = 1;
  34 static int diff_mnemonic_prefix;
  35 static int diff_no_prefix;
  36 static int diff_stat_graph_width;
  37 static int diff_dirstat_permille_default = 30;
  38 static struct diff_options default_diff_options;
  39 static long diff_algorithm;
  40
  41 static char diff_colors[][COLOR_MAXLEN] = {
  42         GIT_COLOR_RESET,
  43         GIT_COLOR_NORMAL,       /* PLAIN */
  44         GIT_COLOR_BOLD,         /* METAINFO */
  45         GIT_COLOR_CYAN,         /* FRAGINFO */
  46         GIT_COLOR_RED,          /* OLD */
  47         GIT_COLOR_GREEN,        /* NEW */
  48         GIT_COLOR_YELLOW,       /* COMMIT */
  49         GIT_COLOR_BG_RED,       /* WHITESPACE */
  50         GIT_COLOR_NORMAL,       /* FUNCINFO */
  51 };
  52
  53 static int parse_diff_color_slot(const char *var, int ofs)
  54 {
  55         if (!strcasecmp(var+ofs, "plain"))
  56                 return DIFF_PLAIN;
  57         if (!strcasecmp(var+ofs, "meta"))
  58                 return DIFF_METAINFO;
  59         if (!strcasecmp(var+ofs, "frag"))
  60                 return DIFF_FRAGINFO;
  61         if (!strcasecmp(var+ofs, "old"))
  62                 return DIFF_FILE_OLD;
  63         if (!strcasecmp(var+ofs, "new"))
  64                 return DIFF_FILE_NEW;
  65         if (!strcasecmp(var+ofs, "commit"))
  66                 return DIFF_COMMIT;
  67         if (!strcasecmp(var+ofs, "whitespace"))
  68                 return DIFF_WHITESPACE;
  69         if (!strcasecmp(var+ofs, "func"))
  70                 return DIFF_FUNCINFO;
  71         return -1;
  72 }
  73
  74 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  75                                 struct strbuf *errmsg)
  76 {
  77         char *params_copy = xstrdup(params_string);
  78         struct string_list params = STRING_LIST_INIT_NODUP;
  79         int ret = 0;
  80         int i;
  81
  82         if (*params_copy)
  83                 string_list_split_in_place(&params, params_copy, ',', -1);
  84         for (i = 0; i < params.nr; i++) {
  85                 const char *p = params.items[i].string;
  86                 if (!strcmp(p, "changes")) {
  87                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  88                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  89                 } else if (!strcmp(p, "lines")) {
  90                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  91                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  92                 } else if (!strcmp(p, "files")) {
  93                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  94                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  95                 } else if (!strcmp(p, "noncumulative")) {
  96                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  97                 } else if (!strcmp(p, "cumulative")) {
  98                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  99                 } else if (isdigit(*p)) {
 100                         char *end;
 101                         int permille = strtoul(p, &end, 10) * 10;
 102                         if (*end == '.' && isdigit(*++end)) {
 103                                 /* only use first digit */
 104                                 permille += *end - '0';
 105                                 /* .. and ignore any further digits */
 106                                 while (isdigit(*++end))
 107                                         ; /* nothing */
 108                         }
 109                         if (!*end)
 110                                 options->dirstat_permille = permille;
 111                         else {
 112                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 113                                             p);
 114                                 ret++;
 115                         }
 116                 } else {
 117                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 118                         ret++;
 119                 }
 120
 121         }
 122         string_list_clear(&params, 0);
 123         free(params_copy);
 124         return ret;
 125 }
 126
 127 static int parse_submodule_params(struct diff_options *options, const char *value)
 128 {
 129         if (!strcmp(value, "log"))
 130                 DIFF_OPT_SET(options, SUBMODULE_LOG);
 131         else if (!strcmp(value, "short"))
 132                 DIFF_OPT_CLR(options, SUBMODULE_LOG);
 133         else
 134                 return -1;
 135         return 0;
 136 }
 137
 138 static int git_config_rename(const char *var, const char *value)
 139 {
 140         if (!value)
 141                 return DIFF_DETECT_RENAME;
 142         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 143                 return  DIFF_DETECT_COPY;
 144         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 145 }
 146
 147 long parse_algorithm_value(const char *value)
 148 {
 149         if (!value)
 150                 return -1;
 151         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 152                 return 0;
 153         else if (!strcasecmp(value, "minimal"))
 154                 return XDF_NEED_MINIMAL;
 155         else if (!strcasecmp(value, "patience"))
 156                 return XDF_PATIENCE_DIFF;
 157         else if (!strcasecmp(value, "histogram"))
 158                 return XDF_HISTOGRAM_DIFF;
 159         return -1;
 160 }
 161
 162 /*
 163  * These are to give UI layer defaults.
 164  * The core-level commands such as git-diff-files should
 165  * never be affected by the setting of diff.renames
 166  * the user happens to have in the configuration file.
 167  */
 168 int git_diff_ui_config(const char *var, const char *value, void *cb)
 169 {
 170         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 171                 diff_use_color_default = git_config_colorbool(var, value);
 172                 return 0;
 173         }
 174         if (!strcmp(var, "diff.context")) {
 175                 diff_context_default = git_config_int(var, value);
 176                 if (diff_context_default < 0)
 177                         return -1;
 178                 return 0;
 179         }
 180         if (!strcmp(var, "diff.renames")) {
 181                 diff_detect_rename_default = git_config_rename(var, value);
 182                 return 0;
 183         }
 184         if (!strcmp(var, "diff.autorefreshindex")) {
 185                 diff_auto_refresh_index = git_config_bool(var, value);
 186                 return 0;
 187         }
 188         if (!strcmp(var, "diff.mnemonicprefix")) {
 189                 diff_mnemonic_prefix = git_config_bool(var, value);
 190                 return 0;
 191         }
 192         if (!strcmp(var, "diff.noprefix")) {
 193                 diff_no_prefix = git_config_bool(var, value);
 194                 return 0;
 195         }
 196         if (!strcmp(var, "diff.statgraphwidth")) {
 197                 diff_stat_graph_width = git_config_int(var, value);
 198                 return 0;
 199         }
 200         if (!strcmp(var, "diff.external"))
 201                 return git_config_string(&external_diff_cmd_cfg, var, value);
 202         if (!strcmp(var, "diff.wordregex"))
 203                 return git_config_string(&diff_word_regex_cfg, var, value);
 204
 205         if (!strcmp(var, "diff.ignoresubmodules"))
 206                 handle_ignore_submodules_arg(&default_diff_options, value);
 207
 208         if (!strcmp(var, "diff.submodule")) {
 209                 if (parse_submodule_params(&default_diff_options, value))
 210                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 211                                 value);
 212                 return 0;
 213         }
 214
 215         if (!strcmp(var, "diff.algorithm")) {
 216                 diff_algorithm = parse_algorithm_value(value);
 217                 if (diff_algorithm < 0)
 218                         return -1;
 219                 return 0;
 220         }
 221
 222         if (git_color_config(var, value, cb) < 0)
 223                 return -1;
 224
 225         return git_diff_basic_config(var, value, cb);
 226 }
 227
 228 int git_diff_basic_config(const char *var, const char *value, void *cb)
 229 {
 230         if (!strcmp(var, "diff.renamelimit")) {
 231                 diff_rename_limit_default = git_config_int(var, value);
 232                 return 0;
 233         }
 234
 235         if (userdiff_config(var, value) < 0)
 236                 return -1;
 237
 238         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 239                 int slot = parse_diff_color_slot(var, 11);
 240                 if (slot < 0)
 241                         return 0;
 242                 if (!value)
 243                         return config_error_nonbool(var);
 244                 color_parse(value, var, diff_colors[slot]);
 245                 return 0;
 246         }
 247
 248         /* like GNU diff's --suppress-blank-empty option  */
 249         if (!strcmp(var, "diff.suppressblankempty") ||
 250                         /* for backwards compatibility */
 251                         !strcmp(var, "diff.suppress-blank-empty")) {
 252                 diff_suppress_blank_empty = git_config_bool(var, value);
 253                 return 0;
 254         }
 255
 256         if (!strcmp(var, "diff.dirstat")) {
 257                 struct strbuf errmsg = STRBUF_INIT;
 258                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 259                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 260                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 261                                 errmsg.buf);
 262                 strbuf_release(&errmsg);
 263                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 264                 return 0;
 265         }
 266
 267         if (!prefixcmp(var, "submodule."))
 268                 return parse_submodule_config_option(var, value);
 269
 270         return git_default_config(var, value, cb);
 271 }
 272
 273 static char *quote_two(const char *one, const char *two)
 274 {
 275         int need_one = quote_c_style(one, NULL, NULL, 1);
 276         int need_two = quote_c_style(two, NULL, NULL, 1);
 277         struct strbuf res = STRBUF_INIT;
 278
 279         if (need_one + need_two) {
 280                 strbuf_addch(&res, '"');
 281                 quote_c_style(one, &res, NULL, 1);
 282                 quote_c_style(two, &res, NULL, 1);
 283                 strbuf_addch(&res, '"');
 284         } else {
 285                 strbuf_addstr(&res, one);
 286                 strbuf_addstr(&res, two);
 287         }
 288         return strbuf_detach(&res, NULL);
 289 }
 290
 291 static const char *external_diff(void)
 292 {
 293         static const char *external_diff_cmd = NULL;
 294         static int done_preparing = 0;
 295
 296         if (done_preparing)
 297                 return external_diff_cmd;
 298         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 299         if (!external_diff_cmd)
 300                 external_diff_cmd = external_diff_cmd_cfg;
 301         done_preparing = 1;
 302         return external_diff_cmd;
 303 }
 304
 305 static struct diff_tempfile {
 306         const char *name; /* filename external diff should read from */
 307         char hex[41];
 308         char mode[10];
 309         char tmp_path[PATH_MAX];
 310 } diff_temp[2];
 311
 312 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 313
 314 struct emit_callback {
 315         int color_diff;
 316         unsigned ws_rule;
 317         int blank_at_eof_in_preimage;
 318         int blank_at_eof_in_postimage;
 319         int lno_in_preimage;
 320         int lno_in_postimage;
 321         sane_truncate_fn truncate;
 322         const char **label_path;
 323         struct diff_words_data *diff_words;
 324         struct diff_options *opt;
 325         int *found_changesp;
 326         struct strbuf *header;
 327 };
 328
 329 static int count_lines(const char *data, int size)
 330 {
 331         int count, ch, completely_empty = 1, nl_just_seen = 0;
 332         count = 0;
 333         while (0 < size--) {
 334                 ch = *data++;
 335                 if (ch == '\n') {
 336                         count++;
 337                         nl_just_seen = 1;
 338                         completely_empty = 0;
 339                 }
 340                 else {
 341                         nl_just_seen = 0;
 342                         completely_empty = 0;
 343                 }
 344         }
 345         if (completely_empty)
 346                 return 0;
 347         if (!nl_just_seen)
 348                 count++; /* no trailing newline */
 349         return count;
 350 }
 351
 352 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 353 {
 354         if (!DIFF_FILE_VALID(one)) {
 355                 mf->ptr = (char *)""; /* does not matter */
 356                 mf->size = 0;
 357                 return 0;
 358         }
 359         else if (diff_populate_filespec(one, 0))
 360                 return -1;
 361
 362         mf->ptr = one->data;
 363         mf->size = one->size;
 364         return 0;
 365 }
 366
 367 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 368 static unsigned long diff_filespec_size(struct diff_filespec *one)
 369 {
 370         if (!DIFF_FILE_VALID(one))
 371                 return 0;
 372         diff_populate_filespec(one, 1);
 373         return one->size;
 374 }
 375
 376 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 377 {
 378         char *ptr = mf->ptr;
 379         long size = mf->size;
 380         int cnt = 0;
 381
 382         if (!size)
 383                 return cnt;
 384         ptr += size - 1; /* pointing at the very end */
 385         if (*ptr != '\n')
 386                 ; /* incomplete line */
 387         else
 388                 ptr--; /* skip the last LF */
 389         while (mf->ptr < ptr) {
 390                 char *prev_eol;
 391                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 392                         if (*prev_eol == '\n')
 393                                 break;
 394                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 395                         break;
 396                 cnt++;
 397                 ptr = prev_eol - 1;
 398         }
 399         return cnt;
 400 }
 401
 402 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 403                                struct emit_callback *ecbdata)
 404 {
 405         int l1, l2, at;
 406         unsigned ws_rule = ecbdata->ws_rule;
 407         l1 = count_trailing_blank(mf1, ws_rule);
 408         l2 = count_trailing_blank(mf2, ws_rule);
 409         if (l2 <= l1) {
 410                 ecbdata->blank_at_eof_in_preimage = 0;
 411                 ecbdata->blank_at_eof_in_postimage = 0;
 412                 return;
 413         }
 414         at = count_lines(mf1->ptr, mf1->size);
 415         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 416
 417         at = count_lines(mf2->ptr, mf2->size);
 418         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 419 }
 420
 421 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 422                         int first, const char *line, int len)
 423 {
 424         int has_trailing_newline, has_trailing_carriage_return;
 425         int nofirst;
 426         FILE *file = o->file;
 427
 428         fputs(diff_line_prefix(o), file);
 429
 430         if (len == 0) {
 431                 has_trailing_newline = (first == '\n');
 432                 has_trailing_carriage_return = (!has_trailing_newline &&
 433                                                 (first == '\r'));
 434                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 435         } else {
 436                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 437                 if (has_trailing_newline)
 438                         len--;
 439                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 440                 if (has_trailing_carriage_return)
 441                         len--;
 442                 nofirst = 0;
 443         }
 444
 445         if (len || !nofirst) {
 446                 fputs(set, file);
 447                 if (!nofirst)
 448                         fputc(first, file);
 449                 fwrite(line, len, 1, file);
 450                 fputs(reset, file);
 451         }
 452         if (has_trailing_carriage_return)
 453                 fputc('\r', file);
 454         if (has_trailing_newline)
 455                 fputc('\n', file);
 456 }
 457
 458 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 459                       const char *line, int len)
 460 {
 461         emit_line_0(o, set, reset, line[0], line+1, len-1);
 462 }
 463
 464 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 465 {
 466         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 467               ecbdata->blank_at_eof_in_preimage &&
 468               ecbdata->blank_at_eof_in_postimage &&
 469               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 470               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 471                 return 0;
 472         return ws_blank_line(line, len, ecbdata->ws_rule);
 473 }
 474
 475 static void emit_add_line(const char *reset,
 476                           struct emit_callback *ecbdata,
 477                           const char *line, int len)
 478 {
 479         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 480         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 481
 482         if (!*ws)
 483                 emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 484         else if (new_blank_line_at_eof(ecbdata, line, len))
 485                 /* Blank line at EOF - paint '+' as well */
 486                 emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 487         else {
 488                 /* Emit just the prefix, then the rest. */
 489                 emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 490                 ws_check_emit(line, len, ecbdata->ws_rule,
 491                               ecbdata->opt->file, set, reset, ws);
 492         }
 493 }
 494
 495 static void emit_hunk_header(struct emit_callback *ecbdata,
 496                              const char *line, int len)
 497 {
 498         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 499         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 500         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 501         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 502         static const char atat[2] = { '@', '@' };
 503         const char *cp, *ep;
 504         struct strbuf msgbuf = STRBUF_INIT;
 505         int org_len = len;
 506         int i = 1;
 507
 508         /*
 509          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 510          * it always is at least 10 bytes long.
 511          */
 512         if (len < 10 ||
 513             memcmp(line, atat, 2) ||
 514             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 515                 emit_line(ecbdata->opt, plain, reset, line, len);
 516                 return;
 517         }
 518         ep += 2; /* skip over @@ */
 519
 520         /* The hunk header in fraginfo color */
 521         strbuf_add(&msgbuf, frag, strlen(frag));
 522         strbuf_add(&msgbuf, line, ep - line);
 523         strbuf_add(&msgbuf, reset, strlen(reset));
 524
 525         /*
 526          * trailing "\r\n"
 527          */
 528         for ( ; i < 3; i++)
 529                 if (line[len - i] == '\r' || line[len - i] == '\n')
 530                         len--;
 531
 532         /* blank before the func header */
 533         for (cp = ep; ep - line < len; ep++)
 534                 if (*ep != ' ' && *ep != '\t')
 535                         break;
 536         if (ep != cp) {
 537                 strbuf_add(&msgbuf, plain, strlen(plain));
 538                 strbuf_add(&msgbuf, cp, ep - cp);
 539                 strbuf_add(&msgbuf, reset, strlen(reset));
 540         }
 541
 542         if (ep < line + len) {
 543                 strbuf_add(&msgbuf, func, strlen(func));
 544                 strbuf_add(&msgbuf, ep, line + len - ep);
 545                 strbuf_add(&msgbuf, reset, strlen(reset));
 546         }
 547
 548         strbuf_add(&msgbuf, line + len, org_len - len);
 549         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 550         strbuf_release(&msgbuf);
 551 }
 552
 553 static struct diff_tempfile *claim_diff_tempfile(void) {
 554         int i;
 555         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 556                 if (!diff_temp[i].name)
 557                         return diff_temp + i;
 558         die("BUG: diff is failing to clean up its tempfiles");
 559 }
 560
 561 static int remove_tempfile_installed;
 562
 563 static void remove_tempfile(void)
 564 {
 565         int i;
 566         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 567                 if (diff_temp[i].name == diff_temp[i].tmp_path)
 568                         unlink_or_warn(diff_temp[i].name);
 569                 diff_temp[i].name = NULL;
 570         }
 571 }
 572
 573 static void remove_tempfile_on_signal(int signo)
 574 {
 575         remove_tempfile();
 576         sigchain_pop(signo);
 577         raise(signo);
 578 }
 579
 580 static void print_line_count(FILE *file, int count)
 581 {
 582         switch (count) {
 583         case 0:
 584                 fprintf(file, "0,0");
 585                 break;
 586         case 1:
 587                 fprintf(file, "1");
 588                 break;
 589         default:
 590                 fprintf(file, "1,%d", count);
 591                 break;
 592         }
 593 }
 594
 595 static void emit_rewrite_lines(struct emit_callback *ecb,
 596                                int prefix, const char *data, int size)
 597 {
 598         const char *endp = NULL;
 599         static const char *nneof = " No newline at end of file\n";
 600         const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 601         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 602
 603         while (0 < size) {
 604                 int len;
 605
 606                 endp = memchr(data, '\n', size);
 607                 len = endp ? (endp - data + 1) : size;
 608                 if (prefix != '+') {
 609                         ecb->lno_in_preimage++;
 610                         emit_line_0(ecb->opt, old, reset, '-',
 611                                     data, len);
 612                 } else {
 613                         ecb->lno_in_postimage++;
 614                         emit_add_line(reset, ecb, data, len);
 615                 }
 616                 size -= len;
 617                 data += len;
 618         }
 619         if (!endp) {
 620                 const char *plain = diff_get_color(ecb->color_diff,
 621                                                    DIFF_PLAIN);
 622                 putc('\n', ecb->opt->file);
 623                 emit_line_0(ecb->opt, plain, reset, '\\',
 624                             nneof, strlen(nneof));
 625         }
 626 }
 627
 628 static void emit_rewrite_diff(const char *name_a,
 629                               const char *name_b,
 630                               struct diff_filespec *one,
 631                               struct diff_filespec *two,
 632                               struct userdiff_driver *textconv_one,
 633                               struct userdiff_driver *textconv_two,
 634                               struct diff_options *o)
 635 {
 636         int lc_a, lc_b;
 637         const char *name_a_tab, *name_b_tab;
 638         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 639         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 640         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 641         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 642         const char *a_prefix, *b_prefix;
 643         char *data_one, *data_two;
 644         size_t size_one, size_two;
 645         struct emit_callback ecbdata;
 646         const char *line_prefix = diff_line_prefix(o);
 647
 648         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 649                 a_prefix = o->b_prefix;
 650                 b_prefix = o->a_prefix;
 651         } else {
 652                 a_prefix = o->a_prefix;
 653                 b_prefix = o->b_prefix;
 654         }
 655
 656         name_a += (*name_a == '/');
 657         name_b += (*name_b == '/');
 658         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 659         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 660
 661         strbuf_reset(&a_name);
 662         strbuf_reset(&b_name);
 663         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 664         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 665
 666         size_one = fill_textconv(textconv_one, one, &data_one);
 667         size_two = fill_textconv(textconv_two, two, &data_two);
 668
 669         memset(&ecbdata, 0, sizeof(ecbdata));
 670         ecbdata.color_diff = want_color(o->use_color);
 671         ecbdata.found_changesp = &o->found_changes;
 672         ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 673         ecbdata.opt = o;
 674         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 675                 mmfile_t mf1, mf2;
 676                 mf1.ptr = (char *)data_one;
 677                 mf2.ptr = (char *)data_two;
 678                 mf1.size = size_one;
 679                 mf2.size = size_two;
 680                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 681         }
 682         ecbdata.lno_in_preimage = 1;
 683         ecbdata.lno_in_postimage = 1;
 684
 685         lc_a = count_lines(data_one, size_one);
 686         lc_b = count_lines(data_two, size_two);
 687         fprintf(o->file,
 688                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 689                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 690                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 691                 line_prefix, fraginfo);
 692         if (!o->irreversible_delete)
 693                 print_line_count(o->file, lc_a);
 694         else
 695                 fprintf(o->file, "?,?");
 696         fprintf(o->file, " +");
 697         print_line_count(o->file, lc_b);
 698         fprintf(o->file, " @@%s\n", reset);
 699         if (lc_a && !o->irreversible_delete)
 700                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 701         if (lc_b)
 702                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 703         if (textconv_one)
 704                 free((char *)data_one);
 705         if (textconv_two)
 706                 free((char *)data_two);
 707 }
 708
 709 struct diff_words_buffer {
 710         mmfile_t text;
 711         long alloc;
 712         struct diff_words_orig {
 713                 const char *begin, *end;
 714         } *orig;
 715         int orig_nr, orig_alloc;
 716 };
 717
 718 static void diff_words_append(char *line, unsigned long len,
 719                 struct diff_words_buffer *buffer)
 720 {
 721         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 722         line++;
 723         len--;
 724         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 725         buffer->text.size += len;
 726         buffer->text.ptr[buffer->text.size] = '\0';
 727 }
 728
 729 struct diff_words_style_elem {
 730         const char *prefix;
 731         const char *suffix;
 732         const char *color; /* NULL; filled in by the setup code if
 733                             * color is enabled */
 734 };
 735
 736 struct diff_words_style {
 737         enum diff_words_type type;
 738         struct diff_words_style_elem new, old, ctx;
 739         const char *newline;
 740 };
 741
 742 static struct diff_words_style diff_words_styles[] = {
 743         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 744         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 745         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 746 };
 747
 748 struct diff_words_data {
 749         struct diff_words_buffer minus, plus;
 750         const char *current_plus;
 751         int last_minus;
 752         struct diff_options *opt;
 753         regex_t *word_regex;
 754         enum diff_words_type type;
 755         struct diff_words_style *style;
 756 };
 757
 758 static int fn_out_diff_words_write_helper(FILE *fp,
 759                                           struct diff_words_style_elem *st_el,
 760                                           const char *newline,
 761                                           size_t count, const char *buf,
 762                                           const char *line_prefix)
 763 {
 764         int print = 0;
 765
 766         while (count) {
 767                 char *p = memchr(buf, '\n', count);
 768                 if (print)
 769                         fputs(line_prefix, fp);
 770                 if (p != buf) {
 771                         if (st_el->color && fputs(st_el->color, fp) < 0)
 772                                 return -1;
 773                         if (fputs(st_el->prefix, fp) < 0 ||
 774                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 775                             fputs(st_el->suffix, fp) < 0)
 776                                 return -1;
 777                         if (st_el->color && *st_el->color
 778                             && fputs(GIT_COLOR_RESET, fp) < 0)
 779                                 return -1;
 780                 }
 781                 if (!p)
 782                         return 0;
 783                 if (fputs(newline, fp) < 0)
 784                         return -1;
 785                 count -= p + 1 - buf;
 786                 buf = p + 1;
 787                 print = 1;
 788         }
 789         return 0;
 790 }
 791
 792 /*
 793  * '--color-words' algorithm can be described as:
 794  *
 795  *   1. collect a the minus/plus lines of a diff hunk, divided into
 796  *      minus-lines and plus-lines;
 797  *
 798  *   2. break both minus-lines and plus-lines into words and
 799  *      place them into two mmfile_t with one word for each line;
 800  *
 801  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 802  *
 803  * And for the common parts of the both file, we output the plus side text.
 804  * diff_words->current_plus is used to trace the current position of the plus file
 805  * which printed. diff_words->last_minus is used to trace the last minus word
 806  * printed.
 807  *
 808  * For '--graph' to work with '--color-words', we need to output the graph prefix
 809  * on each line of color words output. Generally, there are two conditions on
 810  * which we should output the prefix.
 811  *
 812  *   1. diff_words->last_minus == 0 &&
 813  *      diff_words->current_plus == diff_words->plus.text.ptr
 814  *
 815  *      that is: the plus text must start as a new line, and if there is no minus
 816  *      word printed, a graph prefix must be printed.
 817  *
 818  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 819  *      *(diff_words->current_plus - 1) == '\n'
 820  *
 821  *      that is: a graph prefix must be printed following a '\n'
 822  */
 823 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 824 {
 825         if ((diff_words->last_minus == 0 &&
 826                 diff_words->current_plus == diff_words->plus.text.ptr) ||
 827                 (diff_words->current_plus > diff_words->plus.text.ptr &&
 828                 *(diff_words->current_plus - 1) == '\n')) {
 829                 return 1;
 830         } else {
 831                 return 0;
 832         }
 833 }
 834
 835 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 836 {
 837         struct diff_words_data *diff_words = priv;
 838         struct diff_words_style *style = diff_words->style;
 839         int minus_first, minus_len, plus_first, plus_len;
 840         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 841         struct diff_options *opt = diff_words->opt;
 842         const char *line_prefix;
 843
 844         if (line[0] != '@' || parse_hunk_header(line, len,
 845                         &minus_first, &minus_len, &plus_first, &plus_len))
 846                 return;
 847
 848         assert(opt);
 849         line_prefix = diff_line_prefix(opt);
 850
 851         /* POSIX requires that first be decremented by one if len == 0... */
 852         if (minus_len) {
 853                 minus_begin = diff_words->minus.orig[minus_first].begin;
 854                 minus_end =
 855                         diff_words->minus.orig[minus_first + minus_len - 1].end;
 856         } else
 857                 minus_begin = minus_end =
 858                         diff_words->minus.orig[minus_first].end;
 859
 860         if (plus_len) {
 861                 plus_begin = diff_words->plus.orig[plus_first].begin;
 862                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 863         } else
 864                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 865
 866         if (color_words_output_graph_prefix(diff_words)) {
 867                 fputs(line_prefix, diff_words->opt->file);
 868         }
 869         if (diff_words->current_plus != plus_begin) {
 870                 fn_out_diff_words_write_helper(diff_words->opt->file,
 871                                 &style->ctx, style->newline,
 872                                 plus_begin - diff_words->current_plus,
 873                                 diff_words->current_plus, line_prefix);
 874                 if (*(plus_begin - 1) == '\n')
 875                         fputs(line_prefix, diff_words->opt->file);
 876         }
 877         if (minus_begin != minus_end) {
 878                 fn_out_diff_words_write_helper(diff_words->opt->file,
 879                                 &style->old, style->newline,
 880                                 minus_end - minus_begin, minus_begin,
 881                                 line_prefix);
 882         }
 883         if (plus_begin != plus_end) {
 884                 fn_out_diff_words_write_helper(diff_words->opt->file,
 885                                 &style->new, style->newline,
 886                                 plus_end - plus_begin, plus_begin,
 887                                 line_prefix);
 888         }
 889
 890         diff_words->current_plus = plus_end;
 891         diff_words->last_minus = minus_first;
 892 }
 893
 894 /* This function starts looking at *begin, and returns 0 iff a word was found. */
 895 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 896                 int *begin, int *end)
 897 {
 898         if (word_regex && *begin < buffer->size) {
 899                 regmatch_t match[1];
 900                 if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 901                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 902                                         '\n', match[0].rm_eo - match[0].rm_so);
 903                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 904                         *begin += match[0].rm_so;
 905                         return *begin >= *end;
 906                 }
 907                 return -1;
 908         }
 909
 910         /* find the next word */
 911         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 912                 (*begin)++;
 913         if (*begin >= buffer->size)
 914                 return -1;
 915
 916         /* find the end of the word */
 917         *end = *begin + 1;
 918         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 919                 (*end)++;
 920
 921         return 0;
 922 }
 923
 924 /*
 925  * This function splits the words in buffer->text, stores the list with
 926  * newline separator into out, and saves the offsets of the original words
 927  * in buffer->orig.
 928  */
 929 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 930                 regex_t *word_regex)
 931 {
 932         int i, j;
 933         long alloc = 0;
 934
 935         out->size = 0;
 936         out->ptr = NULL;
 937
 938         /* fake an empty "0th" word */
 939         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 940         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 941         buffer->orig_nr = 1;
 942
 943         for (i = 0; i < buffer->text.size; i++) {
 944                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 945                         return;
 946
 947                 /* store original boundaries */
 948                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 949                                 buffer->orig_alloc);
 950                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 951                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 952                 buffer->orig_nr++;
 953
 954                 /* store one word */
 955                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 956                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 957                 out->ptr[out->size + j - i] = '\n';
 958                 out->size += j - i + 1;
 959
 960                 i = j - 1;
 961         }
 962 }
 963
 964 /* this executes the word diff on the accumulated buffers */
 965 static void diff_words_show(struct diff_words_data *diff_words)
 966 {
 967         xpparam_t xpp;
 968         xdemitconf_t xecfg;
 969         mmfile_t minus, plus;
 970         struct diff_words_style *style = diff_words->style;
 971
 972         struct diff_options *opt = diff_words->opt;
 973         const char *line_prefix;
 974
 975         assert(opt);
 976         line_prefix = diff_line_prefix(opt);
 977
 978         /* special case: only removal */
 979         if (!diff_words->plus.text.size) {
 980                 fputs(line_prefix, diff_words->opt->file);
 981                 fn_out_diff_words_write_helper(diff_words->opt->file,
 982                         &style->old, style->newline,
 983                         diff_words->minus.text.size,
 984                         diff_words->minus.text.ptr, line_prefix);
 985                 diff_words->minus.text.size = 0;
 986                 return;
 987         }
 988
 989         diff_words->current_plus = diff_words->plus.text.ptr;
 990         diff_words->last_minus = 0;
 991
 992         memset(&xpp, 0, sizeof(xpp));
 993         memset(&xecfg, 0, sizeof(xecfg));
 994         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 995         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 996         xpp.flags = 0;
 997         /* as only the hunk header will be parsed, we need a 0-context */
 998         xecfg.ctxlen = 0;
 999         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1000                       &xpp, &xecfg);
1001         free(minus.ptr);
1002         free(plus.ptr);
1003         if (diff_words->current_plus != diff_words->plus.text.ptr +
1004                         diff_words->plus.text.size) {
1005                 if (color_words_output_graph_prefix(diff_words))
1006                         fputs(line_prefix, diff_words->opt->file);
1007                 fn_out_diff_words_write_helper(diff_words->opt->file,
1008                         &style->ctx, style->newline,
1009                         diff_words->plus.text.ptr + diff_words->plus.text.size
1010                         - diff_words->current_plus, diff_words->current_plus,
1011                         line_prefix);
1012         }
1013         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1014 }
1015
1016 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1017 static void diff_words_flush(struct emit_callback *ecbdata)
1018 {
1019         if (ecbdata->diff_words->minus.text.size ||
1020             ecbdata->diff_words->plus.text.size)
1021                 diff_words_show(ecbdata->diff_words);
1022 }
1023
1024 static void diff_filespec_load_driver(struct diff_filespec *one)
1025 {
1026         /* Use already-loaded driver */
1027         if (one->driver)
1028                 return;
1029
1030         if (S_ISREG(one->mode))
1031                 one->driver = userdiff_find_by_path(one->path);
1032
1033         /* Fallback to default settings */
1034         if (!one->driver)
1035                 one->driver = userdiff_find_by_name("default");
1036 }
1037
1038 static const char *userdiff_word_regex(struct diff_filespec *one)
1039 {
1040         diff_filespec_load_driver(one);
1041         return one->driver->word_regex;
1042 }
1043
1044 static void init_diff_words_data(struct emit_callback *ecbdata,
1045                                  struct diff_options *orig_opts,
1046                                  struct diff_filespec *one,
1047                                  struct diff_filespec *two)
1048 {
1049         int i;
1050         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1051         memcpy(o, orig_opts, sizeof(struct diff_options));
1052
1053         ecbdata->diff_words =
1054                 xcalloc(1, sizeof(struct diff_words_data));
1055         ecbdata->diff_words->type = o->word_diff;
1056         ecbdata->diff_words->opt = o;
1057         if (!o->word_regex)
1058                 o->word_regex = userdiff_word_regex(one);
1059         if (!o->word_regex)
1060                 o->word_regex = userdiff_word_regex(two);
1061         if (!o->word_regex)
1062                 o->word_regex = diff_word_regex_cfg;
1063         if (o->word_regex) {
1064                 ecbdata->diff_words->word_regex = (regex_t *)
1065                         xmalloc(sizeof(regex_t));
1066                 if (regcomp(ecbdata->diff_words->word_regex,
1067                             o->word_regex,
1068                             REG_EXTENDED | REG_NEWLINE))
1069                         die ("Invalid regular expression: %s",
1070                              o->word_regex);
1071         }
1072         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1073                 if (o->word_diff == diff_words_styles[i].type) {
1074                         ecbdata->diff_words->style =
1075                                 &diff_words_styles[i];
1076                         break;
1077                 }
1078         }
1079         if (want_color(o->use_color)) {
1080                 struct diff_words_style *st = ecbdata->diff_words->style;
1081                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1082                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1083                 st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1084         }
1085 }
1086
1087 static void free_diff_words_data(struct emit_callback *ecbdata)
1088 {
1089         if (ecbdata->diff_words) {
1090                 diff_words_flush(ecbdata);
1091                 free (ecbdata->diff_words->opt);
1092                 free (ecbdata->diff_words->minus.text.ptr);
1093                 free (ecbdata->diff_words->minus.orig);
1094                 free (ecbdata->diff_words->plus.text.ptr);
1095                 free (ecbdata->diff_words->plus.orig);
1096                 if (ecbdata->diff_words->word_regex) {
1097                         regfree(ecbdata->diff_words->word_regex);
1098                         free(ecbdata->diff_words->word_regex);
1099                 }
1100                 free(ecbdata->diff_words);
1101                 ecbdata->diff_words = NULL;
1102         }
1103 }
1104
1105 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1106 {
1107         if (want_color(diff_use_color))
1108                 return diff_colors[ix];
1109         return "";
1110 }
1111
1112 const char *diff_line_prefix(struct diff_options *opt)
1113 {
1114         struct strbuf *msgbuf;
1115         if (!opt->output_prefix)
1116                 return "";
1117
1118         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1119         return msgbuf->buf;
1120 }
1121
1122 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1123 {
1124         const char *cp;
1125         unsigned long allot;
1126         size_t l = len;
1127
1128         if (ecb->truncate)
1129                 return ecb->truncate(line, len);
1130         cp = line;
1131         allot = l;
1132         while (0 < l) {
1133                 (void) utf8_width(&cp, &l);
1134                 if (!cp)
1135                         break; /* truncated in the middle? */
1136         }
1137         return allot - l;
1138 }
1139
1140 static void find_lno(const char *line, struct emit_callback *ecbdata)
1141 {
1142         const char *p;
1143         ecbdata->lno_in_preimage = 0;
1144         ecbdata->lno_in_postimage = 0;
1145         p = strchr(line, '-');
1146         if (!p)
1147                 return; /* cannot happen */
1148         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1149         p = strchr(p, '+');
1150         if (!p)
1151                 return; /* cannot happen */
1152         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1153 }
1154
1155 static void fn_out_consume(void *priv, char *line, unsigned long len)
1156 {
1157         struct emit_callback *ecbdata = priv;
1158         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1159         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1160         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1161         struct diff_options *o = ecbdata->opt;
1162         const char *line_prefix = diff_line_prefix(o);
1163
1164         if (ecbdata->header) {
1165                 fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1166                 strbuf_reset(ecbdata->header);
1167                 ecbdata->header = NULL;
1168         }
1169         *(ecbdata->found_changesp) = 1;
1170
1171         if (ecbdata->label_path[0]) {
1172                 const char *name_a_tab, *name_b_tab;
1173
1174                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1175                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1176
1177                 fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1178                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1179                 fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1180                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1181                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1182         }
1183
1184         if (diff_suppress_blank_empty
1185             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1186                 line[0] = '\n';
1187                 len = 1;
1188         }
1189
1190         if (line[0] == '@') {
1191                 if (ecbdata->diff_words)
1192                         diff_words_flush(ecbdata);
1193                 len = sane_truncate_line(ecbdata, line, len);
1194                 find_lno(line, ecbdata);
1195                 emit_hunk_header(ecbdata, line, len);
1196                 if (line[len-1] != '\n')
1197                         putc('\n', ecbdata->opt->file);
1198                 return;
1199         }
1200
1201         if (len < 1) {
1202                 emit_line(ecbdata->opt, reset, reset, line, len);
1203                 if (ecbdata->diff_words
1204                     && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1205                         fputs("~\n", ecbdata->opt->file);
1206                 return;
1207         }
1208
1209         if (ecbdata->diff_words) {
1210                 if (line[0] == '-') {
1211                         diff_words_append(line, len,
1212                                           &ecbdata->diff_words->minus);
1213                         return;
1214                 } else if (line[0] == '+') {
1215                         diff_words_append(line, len,
1216                                           &ecbdata->diff_words->plus);
1217                         return;
1218                 } else if (!prefixcmp(line, "\\ ")) {
1219                         /*
1220                          * Eat the "no newline at eof" marker as if we
1221                          * saw a "+" or "-" line with nothing on it,
1222                          * and return without diff_words_flush() to
1223                          * defer processing. If this is the end of
1224                          * preimage, more "+" lines may come after it.
1225                          */
1226                         return;
1227                 }
1228                 diff_words_flush(ecbdata);
1229                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1230                         emit_line(ecbdata->opt, plain, reset, line, len);
1231                         fputs("~\n", ecbdata->opt->file);
1232                 } else {
1233                         /*
1234                          * Skip the prefix character, if any.  With
1235                          * diff_suppress_blank_empty, there may be
1236                          * none.
1237                          */
1238                         if (line[0] != '\n') {
1239                               line++;
1240                               len--;
1241                         }
1242                         emit_line(ecbdata->opt, plain, reset, line, len);
1243                 }
1244                 return;
1245         }
1246
1247         if (line[0] != '+') {
1248                 const char *color =
1249                         diff_get_color(ecbdata->color_diff,
1250                                        line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1251                 ecbdata->lno_in_preimage++;
1252                 if (line[0] == ' ')
1253                         ecbdata->lno_in_postimage++;
1254                 emit_line(ecbdata->opt, color, reset, line, len);
1255         } else {
1256                 ecbdata->lno_in_postimage++;
1257                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1258         }
1259 }
1260
1261 static char *pprint_rename(const char *a, const char *b)
1262 {
1263         const char *old = a;
1264         const char *new = b;
1265         struct strbuf name = STRBUF_INIT;
1266         int pfx_length, sfx_length;
1267         int pfx_adjust_for_slash;
1268         int len_a = strlen(a);
1269         int len_b = strlen(b);
1270         int a_midlen, b_midlen;
1271         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1272         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1273
1274         if (qlen_a || qlen_b) {
1275                 quote_c_style(a, &name, NULL, 0);
1276                 strbuf_addstr(&name, " => ");
1277                 quote_c_style(b, &name, NULL, 0);
1278                 return strbuf_detach(&name, NULL);
1279         }
1280
1281         /* Find common prefix */
1282         pfx_length = 0;
1283         while (*old && *new && *old == *new) {
1284                 if (*old == '/')
1285                         pfx_length = old - a + 1;
1286                 old++;
1287                 new++;
1288         }
1289
1290         /* Find common suffix */
1291         old = a + len_a;
1292         new = b + len_b;
1293         sfx_length = 0;
1294         /*
1295          * If there is a common prefix, it must end in a slash.  In
1296          * that case we let this loop run 1 into the prefix to see the
1297          * same slash.
1298          *
1299          * If there is no common prefix, we cannot do this as it would
1300          * underrun the input strings.
1301          */
1302         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1303         while (a + pfx_length - pfx_adjust_for_slash <= old &&
1304                b + pfx_length - pfx_adjust_for_slash <= new &&
1305                *old == *new) {
1306                 if (*old == '/')
1307                         sfx_length = len_a - (old - a);
1308                 old--;
1309                 new--;
1310         }
1311
1312         /*
1313          * pfx{mid-a => mid-b}sfx
1314          * {pfx-a => pfx-b}sfx
1315          * pfx{sfx-a => sfx-b}
1316          * name-a => name-b
1317          */
1318         a_midlen = len_a - pfx_length - sfx_length;
1319         b_midlen = len_b - pfx_length - sfx_length;
1320         if (a_midlen < 0)
1321                 a_midlen = 0;
1322         if (b_midlen < 0)
1323                 b_midlen = 0;
1324
1325         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1326         if (pfx_length + sfx_length) {
1327                 strbuf_add(&name, a, pfx_length);
1328                 strbuf_addch(&name, '{');
1329         }
1330         strbuf_add(&name, a + pfx_length, a_midlen);
1331         strbuf_addstr(&name, " => ");
1332         strbuf_add(&name, b + pfx_length, b_midlen);
1333         if (pfx_length + sfx_length) {
1334                 strbuf_addch(&name, '}');
1335                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1336         }
1337         return strbuf_detach(&name, NULL);
1338 }
1339
1340 struct diffstat_t {
1341         int nr;
1342         int alloc;
1343         struct diffstat_file {
1344                 char *from_name;
1345                 char *name;
1346                 char *print_name;
1347                 unsigned is_unmerged:1;
1348                 unsigned is_binary:1;
1349                 unsigned is_renamed:1;
1350                 unsigned is_interesting:1;
1351                 uintmax_t added, deleted;
1352         } **files;
1353 };
1354
1355 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1356                                           const char *name_a,
1357                                           const char *name_b)
1358 {
1359         struct diffstat_file *x;
1360         x = xcalloc(sizeof (*x), 1);
1361         if (diffstat->nr == diffstat->alloc) {
1362                 diffstat->alloc = alloc_nr(diffstat->alloc);
1363                 diffstat->files = xrealloc(diffstat->files,
1364                                 diffstat->alloc * sizeof(x));
1365         }
1366         diffstat->files[diffstat->nr++] = x;
1367         if (name_b) {
1368                 x->from_name = xstrdup(name_a);
1369                 x->name = xstrdup(name_b);
1370                 x->is_renamed = 1;
1371         }
1372         else {
1373                 x->from_name = NULL;
1374                 x->name = xstrdup(name_a);
1375         }
1376         return x;
1377 }
1378
1379 static void diffstat_consume(void *priv, char *line, unsigned long len)
1380 {
1381         struct diffstat_t *diffstat = priv;
1382         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1383
1384         if (line[0] == '+')
1385                 x->added++;
1386         else if (line[0] == '-')
1387                 x->deleted++;
1388 }
1389
1390 const char mime_boundary_leader[] = "------------";
1391
1392 static int scale_linear(int it, int width, int max_change)
1393 {
1394         if (!it)
1395                 return 0;
1396         /*
1397          * make sure that at least one '-' or '+' is printed if
1398          * there is any change to this path. The easiest way is to
1399          * scale linearly as if the alloted width is one column shorter
1400          * than it is, and then add 1 to the result.
1401          */
1402         return 1 + (it * (width - 1) / max_change);
1403 }
1404
1405 static void show_name(FILE *file,
1406                       const char *prefix, const char *name, int len)
1407 {
1408         fprintf(file, " %s%-*s |", prefix, len, name);
1409 }
1410
1411 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1412 {
1413         if (cnt <= 0)
1414                 return;
1415         fprintf(file, "%s", set);
1416         while (cnt--)
1417                 putc(ch, file);
1418         fprintf(file, "%s", reset);
1419 }
1420
1421 static void fill_print_name(struct diffstat_file *file)
1422 {
1423         char *pname;
1424
1425         if (file->print_name)
1426                 return;
1427
1428         if (!file->is_renamed) {
1429                 struct strbuf buf = STRBUF_INIT;
1430                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1431                         pname = strbuf_detach(&buf, NULL);
1432                 } else {
1433                         pname = file->name;
1434                         strbuf_release(&buf);
1435                 }
1436         } else {
1437                 pname = pprint_rename(file->from_name, file->name);
1438         }
1439         file->print_name = pname;
1440 }
1441
1442 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1443 {
1444         struct strbuf sb = STRBUF_INIT;
1445         int ret;
1446
1447         if (!files) {
1448                 assert(insertions == 0 && deletions == 0);
1449                 return fprintf(fp, "%s\n", " 0 files changed");
1450         }
1451
1452         strbuf_addf(&sb,
1453                     (files == 1) ? " %d file changed" : " %d files changed",
1454                     files);
1455
1456         /*
1457          * For binary diff, the caller may want to print "x files
1458          * changed" with insertions == 0 && deletions == 0.
1459          *
1460          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1461          * is probably less confusing (i.e skip over "2 files changed
1462          * but nothing about added/removed lines? Is this a bug in Git?").
1463          */
1464         if (insertions || deletions == 0) {
1465                 /*
1466                  * TRANSLATORS: "+" in (+) is a line addition marker;
1467                  * do not translate it.
1468                  */
1469                 strbuf_addf(&sb,
1470                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1471                             insertions);
1472         }
1473
1474         if (deletions || insertions == 0) {
1475                 /*
1476                  * TRANSLATORS: "-" in (-) is a line removal marker;
1477                  * do not translate it.
1478                  */
1479                 strbuf_addf(&sb,
1480                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1481                             deletions);
1482         }
1483         strbuf_addch(&sb, '\n');
1484         ret = fputs(sb.buf, fp);
1485         strbuf_release(&sb);
1486         return ret;
1487 }
1488
1489 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1490 {
1491         int i, len, add, del, adds = 0, dels = 0;
1492         uintmax_t max_change = 0, max_len = 0;
1493         int total_files = data->nr, count;
1494         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1495         const char *reset, *add_c, *del_c;
1496         const char *line_prefix = "";
1497         int extra_shown = 0;
1498
1499         if (data->nr == 0)
1500                 return;
1501
1502         line_prefix = diff_line_prefix(options);
1503         count = options->stat_count ? options->stat_count : data->nr;
1504
1505         reset = diff_get_color_opt(options, DIFF_RESET);
1506         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1507         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1508
1509         /*
1510          * Find the longest filename and max number of changes
1511          */
1512         for (i = 0; (i < count) && (i < data->nr); i++) {
1513                 struct diffstat_file *file = data->files[i];
1514                 uintmax_t change = file->added + file->deleted;
1515
1516                 if (!file->is_interesting && (change == 0)) {
1517                         count++; /* not shown == room for one more */
1518                         continue;
1519                 }
1520                 fill_print_name(file);
1521                 len = strlen(file->print_name);
1522                 if (max_len < len)
1523                         max_len = len;
1524
1525                 if (file->is_unmerged) {
1526                         /* "Unmerged" is 8 characters */
1527                         bin_width = bin_width < 8 ? 8 : bin_width;
1528                         continue;
1529                 }
1530                 if (file->is_binary) {
1531                         /* "Bin XXX -> YYY bytes" */
1532                         int w = 14 + decimal_width(file->added)
1533                                 + decimal_width(file->deleted);
1534                         bin_width = bin_width < w ? w : bin_width;
1535                         /* Display change counts aligned with "Bin" */
1536                         number_width = 3;
1537                         continue;
1538                 }
1539
1540                 if (max_change < change)
1541                         max_change = change;
1542         }
1543         count = i; /* where we can stop scanning in data->files[] */
1544
1545         /*
1546          * We have width = stat_width or term_columns() columns total.
1547          * We want a maximum of min(max_len, stat_name_width) for the name part.
1548          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1549          * We also need 1 for " " and 4 + decimal_width(max_change)
1550          * for " | NNNN " and one the empty column at the end, altogether
1551          * 6 + decimal_width(max_change).
1552          *
1553          * If there's not enough space, we will use the smaller of
1554          * stat_name_width (if set) and 5/8*width for the filename,
1555          * and the rest for constant elements + graph part, but no more
1556          * than stat_graph_width for the graph part.
1557          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1558          * for the standard terminal size).
1559          *
1560          * In other words: stat_width limits the maximum width, and
1561          * stat_name_width fixes the maximum width of the filename,
1562          * and is also used to divide available columns if there
1563          * aren't enough.
1564          *
1565          * Binary files are displayed with "Bin XXX -> YYY bytes"
1566          * instead of the change count and graph. This part is treated
1567          * similarly to the graph part, except that it is not
1568          * "scaled". If total width is too small to accommodate the
1569          * guaranteed minimum width of the filename part and the
1570          * separators and this message, this message will "overflow"
1571          * making the line longer than the maximum width.
1572          */
1573
1574         if (options->stat_width == -1)
1575                 width = term_columns() - options->output_prefix_length;
1576         else
1577                 width = options->stat_width ? options->stat_width : 80;
1578         number_width = decimal_width(max_change) > number_width ?
1579                 decimal_width(max_change) : number_width;
1580
1581         if (options->stat_graph_width == -1)
1582                 options->stat_graph_width = diff_stat_graph_width;
1583
1584         /*
1585          * Guarantee 3/8*16==6 for the graph part
1586          * and 5/8*16==10 for the filename part
1587          */
1588         if (width < 16 + 6 + number_width)
1589                 width = 16 + 6 + number_width;
1590
1591         /*
1592          * First assign sizes that are wanted, ignoring available width.
1593          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1594          * starting from "XXX" should fit in graph_width.
1595          */
1596         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1597         if (options->stat_graph_width &&
1598             options->stat_graph_width < graph_width)
1599                 graph_width = options->stat_graph_width;
1600
1601         name_width = (options->stat_name_width > 0 &&
1602                       options->stat_name_width < max_len) ?
1603                 options->stat_name_width : max_len;
1604
1605         /*
1606          * Adjust adjustable widths not to exceed maximum width
1607          */
1608         if (name_width + number_width + 6 + graph_width > width) {
1609                 if (graph_width > width * 3/8 - number_width - 6) {
1610                         graph_width = width * 3/8 - number_width - 6;
1611                         if (graph_width < 6)
1612                                 graph_width = 6;
1613                 }
1614
1615                 if (options->stat_graph_width &&
1616                     graph_width > options->stat_graph_width)
1617                         graph_width = options->stat_graph_width;
1618                 if (name_width > width - number_width - 6 - graph_width)
1619                         name_width = width - number_width - 6 - graph_width;
1620                 else
1621                         graph_width = width - number_width - 6 - name_width;
1622         }
1623
1624         /*
1625          * From here name_width is the width of the name area,
1626          * and graph_width is the width of the graph area.
1627          * max_change is used to scale graph properly.
1628          */
1629         for (i = 0; i < count; i++) {
1630                 const char *prefix = "";
1631                 struct diffstat_file *file = data->files[i];
1632                 char *name = file->print_name;
1633                 uintmax_t added = file->added;
1634                 uintmax_t deleted = file->deleted;
1635                 int name_len;
1636
1637                 if (!file->is_interesting && (added + deleted == 0))
1638                         continue;
1639
1640                 /*
1641                  * "scale" the filename
1642                  */
1643                 len = name_width;
1644                 name_len = strlen(name);
1645                 if (name_width < name_len) {
1646                         char *slash;
1647                         prefix = "...";
1648                         len -= 3;
1649                         name += name_len - len;
1650                         slash = strchr(name, '/');
1651                         if (slash)
1652                                 name = slash;
1653                 }
1654
1655                 if (file->is_binary) {
1656                         fprintf(options->file, "%s", line_prefix);
1657                         show_name(options->file, prefix, name, len);
1658                         fprintf(options->file, " %*s", number_width, "Bin");
1659                         if (!added && !deleted) {
1660                                 putc('\n', options->file);
1661                                 continue;
1662                         }
1663                         fprintf(options->file, " %s%"PRIuMAX"%s",
1664                                 del_c, deleted, reset);
1665                         fprintf(options->file, " -> ");
1666                         fprintf(options->file, "%s%"PRIuMAX"%s",
1667                                 add_c, added, reset);
1668                         fprintf(options->file, " bytes");
1669                         fprintf(options->file, "\n");
1670                         continue;
1671                 }
1672                 else if (file->is_unmerged) {
1673                         fprintf(options->file, "%s", line_prefix);
1674                         show_name(options->file, prefix, name, len);
1675                         fprintf(options->file, " Unmerged\n");
1676                         continue;
1677                 }
1678
1679                 /*
1680                  * scale the add/delete
1681                  */
1682                 add = added;
1683                 del = deleted;
1684
1685                 if (graph_width <= max_change) {
1686                         int total = add + del;
1687
1688                         total = scale_linear(add + del, graph_width, max_change);
1689                         if (total < 2 && add && del)
1690                                 /* width >= 2 due to the sanity check */
1691                                 total = 2;
1692                         if (add < del) {
1693                                 add = scale_linear(add, graph_width, max_change);
1694                                 del = total - add;
1695                         } else {
1696                                 del = scale_linear(del, graph_width, max_change);
1697                                 add = total - del;
1698                         }
1699                 }
1700                 fprintf(options->file, "%s", line_prefix);
1701                 show_name(options->file, prefix, name, len);
1702                 fprintf(options->file, " %*"PRIuMAX"%s",
1703                         number_width, added + deleted,
1704                         added + deleted ? " " : "");
1705                 show_graph(options->file, '+', add, add_c, reset);
1706                 show_graph(options->file, '-', del, del_c, reset);
1707                 fprintf(options->file, "\n");
1708         }
1709
1710         for (i = 0; i < data->nr; i++) {
1711                 struct diffstat_file *file = data->files[i];
1712                 uintmax_t added = file->added;
1713                 uintmax_t deleted = file->deleted;
1714
1715                 if (file->is_unmerged ||
1716                     (!file->is_interesting && (added + deleted == 0))) {
1717                         total_files--;
1718                         continue;
1719                 }
1720
1721                 if (!file->is_binary) {
1722                         adds += added;
1723                         dels += deleted;
1724                 }
1725                 if (i < count)
1726                         continue;
1727                 if (!extra_shown)
1728                         fprintf(options->file, "%s ...\n", line_prefix);
1729                 extra_shown = 1;
1730         }
1731         fprintf(options->file, "%s", line_prefix);
1732         print_stat_summary(options->file, total_files, adds, dels);
1733 }
1734
1735 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1736 {
1737         int i, adds = 0, dels = 0, total_files = data->nr;
1738
1739         if (data->nr == 0)
1740                 return;
1741
1742         for (i = 0; i < data->nr; i++) {
1743                 int added = data->files[i]->added;
1744                 int deleted= data->files[i]->deleted;
1745
1746                 if (data->files[i]->is_unmerged ||
1747                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1748                         total_files--;
1749                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1750                         adds += added;
1751                         dels += deleted;
1752                 }
1753         }
1754         fprintf(options->file, "%s", diff_line_prefix(options));
1755         print_stat_summary(options->file, total_files, adds, dels);
1756 }
1757
1758 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1759 {
1760         int i;
1761
1762         if (data->nr == 0)
1763                 return;
1764
1765         for (i = 0; i < data->nr; i++) {
1766                 struct diffstat_file *file = data->files[i];
1767
1768                 fprintf(options->file, "%s", diff_line_prefix(options));
1769
1770                 if (file->is_binary)
1771                         fprintf(options->file, "-\t-\t");
1772                 else
1773                         fprintf(options->file,
1774                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1775                                 file->added, file->deleted);
1776                 if (options->line_termination) {
1777                         fill_print_name(file);
1778                         if (!file->is_renamed)
1779                                 write_name_quoted(file->name, options->file,
1780                                                   options->line_termination);
1781                         else {
1782                                 fputs(file->print_name, options->file);
1783                                 putc(options->line_termination, options->file);
1784                         }
1785                 } else {
1786                         if (file->is_renamed) {
1787                                 putc('\0', options->file);
1788                                 write_name_quoted(file->from_name, options->file, '\0');
1789                         }
1790                         write_name_quoted(file->name, options->file, '\0');
1791                 }
1792         }
1793 }
1794
1795 struct dirstat_file {
1796         const char *name;
1797         unsigned long changed;
1798 };
1799
1800 struct dirstat_dir {
1801         struct dirstat_file *files;
1802         int alloc, nr, permille, cumulative;
1803 };
1804
1805 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1806                 unsigned long changed, const char *base, int baselen)
1807 {
1808         unsigned long this_dir = 0;
1809         unsigned int sources = 0;
1810         const char *line_prefix = diff_line_prefix(opt);
1811
1812         while (dir->nr) {
1813                 struct dirstat_file *f = dir->files;
1814                 int namelen = strlen(f->name);
1815                 unsigned long this;
1816                 char *slash;
1817
1818                 if (namelen < baselen)
1819                         break;
1820                 if (memcmp(f->name, base, baselen))
1821                         break;
1822                 slash = strchr(f->name + baselen, '/');
1823                 if (slash) {
1824                         int newbaselen = slash + 1 - f->name;
1825                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1826                         sources++;
1827                 } else {
1828                         this = f->changed;
1829                         dir->files++;
1830                         dir->nr--;
1831                         sources += 2;
1832                 }
1833                 this_dir += this;
1834         }
1835
1836         /*
1837          * We don't report dirstat's for
1838          *  - the top level
1839          *  - or cases where everything came from a single directory
1840          *    under this directory (sources == 1).
1841          */
1842         if (baselen && sources != 1) {
1843                 if (this_dir) {
1844                         int permille = this_dir * 1000 / changed;
1845                         if (permille >= dir->permille) {
1846                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1847                                         permille / 10, permille % 10, baselen, base);
1848                                 if (!dir->cumulative)
1849                                         return 0;
1850                         }
1851                 }
1852         }
1853         return this_dir;
1854 }
1855
1856 static int dirstat_compare(const void *_a, const void *_b)
1857 {
1858         const struct dirstat_file *a = _a;
1859         const struct dirstat_file *b = _b;
1860         return strcmp(a->name, b->name);
1861 }
1862
1863 static void show_dirstat(struct diff_options *options)
1864 {
1865         int i;
1866         unsigned long changed;
1867         struct dirstat_dir dir;
1868         struct diff_queue_struct *q = &diff_queued_diff;
1869
1870         dir.files = NULL;
1871         dir.alloc = 0;
1872         dir.nr = 0;
1873         dir.permille = options->dirstat_permille;
1874         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1875
1876         changed = 0;
1877         for (i = 0; i < q->nr; i++) {
1878                 struct diff_filepair *p = q->queue[i];
1879                 const char *name;
1880                 unsigned long copied, added, damage;
1881                 int content_changed;
1882
1883                 name = p->two->path ? p->two->path : p->one->path;
1884
1885                 if (p->one->sha1_valid && p->two->sha1_valid)
1886                         content_changed = hashcmp(p->one->sha1, p->two->sha1);
1887                 else
1888                         content_changed = 1;
1889
1890                 if (!content_changed) {
1891                         /*
1892                          * The SHA1 has not changed, so pre-/post-content is
1893                          * identical. We can therefore skip looking at the
1894                          * file contents altogether.
1895                          */
1896                         damage = 0;
1897                         goto found_damage;
1898                 }
1899
1900                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1901                         /*
1902                          * In --dirstat-by-file mode, we don't really need to
1903                          * look at the actual file contents at all.
1904                          * The fact that the SHA1 changed is enough for us to
1905                          * add this file to the list of results
1906                          * (with each file contributing equal damage).
1907                          */
1908                         damage = 1;
1909                         goto found_damage;
1910                 }
1911
1912                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1913                         diff_populate_filespec(p->one, 0);
1914                         diff_populate_filespec(p->two, 0);
1915                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1916                                                &copied, &added);
1917                         diff_free_filespec_data(p->one);
1918                         diff_free_filespec_data(p->two);
1919                 } else if (DIFF_FILE_VALID(p->one)) {
1920                         diff_populate_filespec(p->one, 1);
1921                         copied = added = 0;
1922                         diff_free_filespec_data(p->one);
1923                 } else if (DIFF_FILE_VALID(p->two)) {
1924                         diff_populate_filespec(p->two, 1);
1925                         copied = 0;
1926                         added = p->two->size;
1927                         diff_free_filespec_data(p->two);
1928                 } else
1929                         continue;
1930
1931                 /*
1932                  * Original minus copied is the removed material,
1933                  * added is the new material.  They are both damages
1934                  * made to the preimage.
1935                  * If the resulting damage is zero, we know that
1936                  * diffcore_count_changes() considers the two entries to
1937                  * be identical, but since content_changed is true, we
1938                  * know that there must have been _some_ kind of change,
1939                  * so we force all entries to have damage > 0.
1940                  */
1941                 damage = (p->one->size - copied) + added;
1942                 if (!damage)
1943                         damage = 1;
1944
1945 found_damage:
1946                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1947                 dir.files[dir.nr].name = name;
1948                 dir.files[dir.nr].changed = damage;
1949                 changed += damage;
1950                 dir.nr++;
1951         }
1952
1953         /* This can happen even with many files, if everything was renames */
1954         if (!changed)
1955                 return;
1956
1957         /* Show all directories with more than x% of the changes */
1958         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1959         gather_dirstat(options, &dir, changed, "", 0);
1960 }
1961
1962 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1963 {
1964         int i;
1965         unsigned long changed;
1966         struct dirstat_dir dir;
1967
1968         if (data->nr == 0)
1969                 return;
1970
1971         dir.files = NULL;
1972         dir.alloc = 0;
1973         dir.nr = 0;
1974         dir.permille = options->dirstat_permille;
1975         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1976
1977         changed = 0;
1978         for (i = 0; i < data->nr; i++) {
1979                 struct diffstat_file *file = data->files[i];
1980                 unsigned long damage = file->added + file->deleted;
1981                 if (file->is_binary)
1982                         /*
1983                          * binary files counts bytes, not lines. Must find some
1984                          * way to normalize binary bytes vs. textual lines.
1985                          * The following heuristic assumes that there are 64
1986                          * bytes per "line".
1987                          * This is stupid and ugly, but very cheap...
1988                          */
1989                         damage = (damage + 63) / 64;
1990                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1991                 dir.files[dir.nr].name = file->name;
1992                 dir.files[dir.nr].changed = damage;
1993                 changed += damage;
1994                 dir.nr++;
1995         }
1996
1997         /* This can happen even with many files, if everything was renames */
1998         if (!changed)
1999                 return;
2000
2001         /* Show all directories with more than x% of the changes */
2002         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2003         gather_dirstat(options, &dir, changed, "", 0);
2004 }
2005
2006 static void free_diffstat_info(struct diffstat_t *diffstat)
2007 {
2008         int i;
2009         for (i = 0; i < diffstat->nr; i++) {
2010                 struct diffstat_file *f = diffstat->files[i];
2011                 if (f->name != f->print_name)
2012                         free(f->print_name);
2013                 free(f->name);
2014                 free(f->from_name);
2015                 free(f);
2016         }
2017         free(diffstat->files);
2018 }
2019
2020 struct checkdiff_t {
2021         const char *filename;
2022         int lineno;
2023         int conflict_marker_size;
2024         struct diff_options *o;
2025         unsigned ws_rule;
2026         unsigned status;
2027 };
2028
2029 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2030 {
2031         char firstchar;
2032         int cnt;
2033
2034         if (len < marker_size + 1)
2035                 return 0;
2036         firstchar = line[0];
2037         switch (firstchar) {
2038         case '=': case '>': case '<': case '|':
2039                 break;
2040         default:
2041                 return 0;
2042         }
2043         for (cnt = 1; cnt < marker_size; cnt++)
2044                 if (line[cnt] != firstchar)
2045                         return 0;
2046         /* line[1] thru line[marker_size-1] are same as firstchar */
2047         if (len < marker_size + 1 || !isspace(line[marker_size]))
2048                 return 0;
2049         return 1;
2050 }
2051
2052 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2053 {
2054         struct checkdiff_t *data = priv;
2055         int marker_size = data->conflict_marker_size;
2056         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2057         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2058         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2059         char *err;
2060         const char *line_prefix;
2061
2062         assert(data->o);
2063         line_prefix = diff_line_prefix(data->o);
2064
2065         if (line[0] == '+') {
2066                 unsigned bad;
2067                 data->lineno++;
2068                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2069                         data->status |= 1;
2070                         fprintf(data->o->file,
2071                                 "%s%s:%d: leftover conflict marker\n",
2072                                 line_prefix, data->filename, data->lineno);
2073                 }
2074                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2075                 if (!bad)
2076                         return;
2077                 data->status |= bad;
2078                 err = whitespace_error_string(bad);
2079                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2080                         line_prefix, data->filename, data->lineno, err);
2081                 free(err);
2082                 emit_line(data->o, set, reset, line, 1);
2083                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2084                               data->o->file, set, reset, ws);
2085         } else if (line[0] == ' ') {
2086                 data->lineno++;
2087         } else if (line[0] == '@') {
2088                 char *plus = strchr(line, '+');
2089                 if (plus)
2090                         data->lineno = strtol(plus, NULL, 10) - 1;
2091                 else
2092                         die("invalid diff");
2093         }
2094 }
2095
2096 static unsigned char *deflate_it(char *data,
2097                                  unsigned long size,
2098                                  unsigned long *result_size)
2099 {
2100         int bound;
2101         unsigned char *deflated;
2102         git_zstream stream;
2103
2104         memset(&stream, 0, sizeof(stream));
2105         git_deflate_init(&stream, zlib_compression_level);
2106         bound = git_deflate_bound(&stream, size);
2107         deflated = xmalloc(bound);
2108         stream.next_out = deflated;
2109         stream.avail_out = bound;
2110
2111         stream.next_in = (unsigned char *)data;
2112         stream.avail_in = size;
2113         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2114                 ; /* nothing */
2115         git_deflate_end(&stream);
2116         *result_size = stream.total_out;
2117         return deflated;
2118 }
2119
2120 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2121                                   const char *prefix)
2122 {
2123         void *cp;
2124         void *delta;
2125         void *deflated;
2126         void *data;
2127         unsigned long orig_size;
2128         unsigned long delta_size;
2129         unsigned long deflate_size;
2130         unsigned long data_size;
2131
2132         /* We could do deflated delta, or we could do just deflated two,
2133          * whichever is smaller.
2134          */
2135         delta = NULL;
2136         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2137         if (one->size && two->size) {
2138                 delta = diff_delta(one->ptr, one->size,
2139                                    two->ptr, two->size,
2140                                    &delta_size, deflate_size);
2141                 if (delta) {
2142                         void *to_free = delta;
2143                         orig_size = delta_size;
2144                         delta = deflate_it(delta, delta_size, &delta_size);
2145                         free(to_free);
2146                 }
2147         }
2148
2149         if (delta && delta_size < deflate_size) {
2150                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2151                 free(deflated);
2152                 data = delta;
2153                 data_size = delta_size;
2154         }
2155         else {
2156                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2157                 free(delta);
2158                 data = deflated;
2159                 data_size = deflate_size;
2160         }
2161
2162         /* emit data encoded in base85 */
2163         cp = data;
2164         while (data_size) {
2165                 int bytes = (52 < data_size) ? 52 : data_size;
2166                 char line[70];
2167                 data_size -= bytes;
2168                 if (bytes <= 26)
2169                         line[0] = bytes + 'A' - 1;
2170                 else
2171                         line[0] = bytes - 26 + 'a' - 1;
2172                 encode_85(line + 1, cp, bytes);
2173                 cp = (char *) cp + bytes;
2174                 fprintf(file, "%s", prefix);
2175                 fputs(line, file);
2176                 fputc('\n', file);
2177         }
2178         fprintf(file, "%s\n", prefix);
2179         free(data);
2180 }
2181
2182 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2183                              const char *prefix)
2184 {
2185         fprintf(file, "%sGIT binary patch\n", prefix);
2186         emit_binary_diff_body(file, one, two, prefix);
2187         emit_binary_diff_body(file, two, one, prefix);
2188 }
2189
2190 int diff_filespec_is_binary(struct diff_filespec *one)
2191 {
2192         if (one->is_binary == -1) {
2193                 diff_filespec_load_driver(one);
2194                 if (one->driver->binary != -1)
2195                         one->is_binary = one->driver->binary;
2196                 else {
2197                         if (!one->data && DIFF_FILE_VALID(one))
2198                                 diff_populate_filespec(one, 0);
2199                         if (one->data)
2200                                 one->is_binary = buffer_is_binary(one->data,
2201                                                 one->size);
2202                         if (one->is_binary == -1)
2203                                 one->is_binary = 0;
2204                 }
2205         }
2206         return one->is_binary;
2207 }
2208
2209 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2210 {
2211         diff_filespec_load_driver(one);
2212         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2213 }
2214
2215 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2216 {
2217         if (!options->a_prefix)
2218                 options->a_prefix = a;
2219         if (!options->b_prefix)
2220                 options->b_prefix = b;
2221 }
2222
2223 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2224 {
2225         if (!DIFF_FILE_VALID(one))
2226                 return NULL;
2227
2228         diff_filespec_load_driver(one);
2229         return userdiff_get_textconv(one->driver);
2230 }
2231
2232 static void builtin_diff(const char *name_a,
2233                          const char *name_b,
2234                          struct diff_filespec *one,
2235                          struct diff_filespec *two,
2236                          const char *xfrm_msg,
2237                          int must_show_header,
2238                          struct diff_options *o,
2239                          int complete_rewrite)
2240 {
2241         mmfile_t mf1, mf2;
2242         const char *lbl[2];
2243         char *a_one, *b_two;
2244         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2245         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2246         const char *a_prefix, *b_prefix;
2247         struct userdiff_driver *textconv_one = NULL;
2248         struct userdiff_driver *textconv_two = NULL;
2249         struct strbuf header = STRBUF_INIT;
2250         const char *line_prefix = diff_line_prefix(o);
2251
2252         if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2253                         (!one->mode || S_ISGITLINK(one->mode)) &&
2254                         (!two->mode || S_ISGITLINK(two->mode))) {
2255                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2256                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2257                 show_submodule_summary(o->file, one ? one->path : two->path,
2258                                 one->sha1, two->sha1, two->dirty_submodule,
2259                                 meta, del, add, reset);
2260                 return;
2261         }
2262
2263         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2264                 textconv_one = get_textconv(one);
2265                 textconv_two = get_textconv(two);
2266         }
2267
2268         diff_set_mnemonic_prefix(o, "a/", "b/");
2269         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2270                 a_prefix = o->b_prefix;
2271                 b_prefix = o->a_prefix;
2272         } else {
2273                 a_prefix = o->a_prefix;
2274                 b_prefix = o->b_prefix;
2275         }
2276
2277         /* Never use a non-valid filename anywhere if at all possible */
2278         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2279         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2280
2281         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2282         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2283         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2284         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2285         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2286         if (lbl[0][0] == '/') {
2287                 /* /dev/null */
2288                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2289                 if (xfrm_msg)
2290                         strbuf_addstr(&header, xfrm_msg);
2291                 must_show_header = 1;
2292         }
2293         else if (lbl[1][0] == '/') {
2294                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2295                 if (xfrm_msg)
2296                         strbuf_addstr(&header, xfrm_msg);
2297                 must_show_header = 1;
2298         }
2299         else {
2300                 if (one->mode != two->mode) {
2301                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2302                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2303                         must_show_header = 1;
2304                 }
2305                 if (xfrm_msg)
2306                         strbuf_addstr(&header, xfrm_msg);
2307
2308                 /*
2309                  * we do not run diff between different kind
2310                  * of objects.
2311                  */
2312                 if ((one->mode ^ two->mode) & S_IFMT)
2313                         goto free_ab_and_return;
2314                 if (complete_rewrite &&
2315                     (textconv_one || !diff_filespec_is_binary(one)) &&
2316                     (textconv_two || !diff_filespec_is_binary(two))) {
2317                         fprintf(o->file, "%s", header.buf);
2318                         strbuf_reset(&header);
2319                         emit_rewrite_diff(name_a, name_b, one, two,
2320                                                 textconv_one, textconv_two, o);
2321                         o->found_changes = 1;
2322                         goto free_ab_and_return;
2323                 }
2324         }
2325
2326         if (o->irreversible_delete && lbl[1][0] == '/') {
2327                 fprintf(o->file, "%s", header.buf);
2328                 strbuf_reset(&header);
2329                 goto free_ab_and_return;
2330         } else if (!DIFF_OPT_TST(o, TEXT) &&
2331             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2332               (!textconv_two && diff_filespec_is_binary(two)) )) {
2333                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2334                         die("unable to read files to diff");
2335                 /* Quite common confusing case */
2336                 if (mf1.size == mf2.size &&
2337                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2338                         if (must_show_header)
2339                                 fprintf(o->file, "%s", header.buf);
2340                         goto free_ab_and_return;
2341                 }
2342                 fprintf(o->file, "%s", header.buf);
2343                 strbuf_reset(&header);
2344                 if (DIFF_OPT_TST(o, BINARY))
2345                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2346                 else
2347                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2348                                 line_prefix, lbl[0], lbl[1]);
2349                 o->found_changes = 1;
2350         } else {
2351                 /* Crazy xdl interfaces.. */
2352                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2353                 xpparam_t xpp;
2354                 xdemitconf_t xecfg;
2355                 struct emit_callback ecbdata;
2356                 const struct userdiff_funcname *pe;
2357
2358                 if (must_show_header) {
2359                         fprintf(o->file, "%s", header.buf);
2360                         strbuf_reset(&header);
2361                 }
2362
2363                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2364                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2365
2366                 pe = diff_funcname_pattern(one);
2367                 if (!pe)
2368                         pe = diff_funcname_pattern(two);
2369
2370                 memset(&xpp, 0, sizeof(xpp));
2371                 memset(&xecfg, 0, sizeof(xecfg));
2372                 memset(&ecbdata, 0, sizeof(ecbdata));
2373                 ecbdata.label_path = lbl;
2374                 ecbdata.color_diff = want_color(o->use_color);
2375                 ecbdata.found_changesp = &o->found_changes;
2376                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2377                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2378                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2379                 ecbdata.opt = o;
2380                 ecbdata.header = header.len ? &header : NULL;
2381                 xpp.flags = o->xdl_opts;
2382                 xecfg.ctxlen = o->context;
2383                 xecfg.interhunkctxlen = o->interhunkcontext;
2384                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2385                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2386                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2387                 if (pe)
2388                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2389                 if (!diffopts)
2390                         ;
2391                 else if (!prefixcmp(diffopts, "--unified="))
2392                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2393                 else if (!prefixcmp(diffopts, "-u"))
2394                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2395                 if (o->word_diff)
2396                         init_diff_words_data(&ecbdata, o, one, two);
2397                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2398                               &xpp, &xecfg);
2399                 if (o->word_diff)
2400                         free_diff_words_data(&ecbdata);
2401                 if (textconv_one)
2402                         free(mf1.ptr);
2403                 if (textconv_two)
2404                         free(mf2.ptr);
2405                 xdiff_clear_find_func(&xecfg);
2406         }
2407
2408  free_ab_and_return:
2409         strbuf_release(&header);
2410         diff_free_filespec_data(one);
2411         diff_free_filespec_data(two);
2412         free(a_one);
2413         free(b_two);
2414         return;
2415 }
2416
2417 static void builtin_diffstat(const char *name_a, const char *name_b,
2418                              struct diff_filespec *one,
2419                              struct diff_filespec *two,
2420                              struct diffstat_t *diffstat,
2421                              struct diff_options *o,
2422                              struct diff_filepair *p)
2423 {
2424         mmfile_t mf1, mf2;
2425         struct diffstat_file *data;
2426         int same_contents;
2427         int complete_rewrite = 0;
2428
2429         if (!DIFF_PAIR_UNMERGED(p)) {
2430                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2431                         complete_rewrite = 1;
2432         }
2433
2434         data = diffstat_add(diffstat, name_a, name_b);
2435         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2436
2437         if (!one || !two) {
2438                 data->is_unmerged = 1;
2439                 return;
2440         }
2441
2442         same_contents = !hashcmp(one->sha1, two->sha1);
2443
2444         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2445                 data->is_binary = 1;
2446                 if (same_contents) {
2447                         data->added = 0;
2448                         data->deleted = 0;
2449                 } else {
2450                         data->added = diff_filespec_size(two);
2451                         data->deleted = diff_filespec_size(one);
2452                 }
2453         }
2454
2455         else if (complete_rewrite) {
2456                 diff_populate_filespec(one, 0);
2457                 diff_populate_filespec(two, 0);
2458                 data->deleted = count_lines(one->data, one->size);
2459                 data->added = count_lines(two->data, two->size);
2460         }
2461
2462         else if (!same_contents) {
2463                 /* Crazy xdl interfaces.. */
2464                 xpparam_t xpp;
2465                 xdemitconf_t xecfg;
2466
2467                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2468                         die("unable to read files to diff");
2469
2470                 memset(&xpp, 0, sizeof(xpp));
2471                 memset(&xecfg, 0, sizeof(xecfg));
2472                 xpp.flags = o->xdl_opts;
2473                 xecfg.ctxlen = o->context;
2474                 xecfg.interhunkctxlen = o->interhunkcontext;
2475                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2476                               &xpp, &xecfg);
2477         }
2478
2479         diff_free_filespec_data(one);
2480         diff_free_filespec_data(two);
2481 }
2482
2483 static void builtin_checkdiff(const char *name_a, const char *name_b,
2484                               const char *attr_path,
2485                               struct diff_filespec *one,
2486                               struct diff_filespec *two,
2487                               struct diff_options *o)
2488 {
2489         mmfile_t mf1, mf2;
2490         struct checkdiff_t data;
2491
2492         if (!two)
2493                 return;
2494
2495         memset(&data, 0, sizeof(data));
2496         data.filename = name_b ? name_b : name_a;
2497         data.lineno = 0;
2498         data.o = o;
2499         data.ws_rule = whitespace_rule(attr_path);
2500         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2501
2502         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2503                 die("unable to read files to diff");
2504
2505         /*
2506          * All the other codepaths check both sides, but not checking
2507          * the "old" side here is deliberate.  We are checking the newly
2508          * introduced changes, and as long as the "new" side is text, we
2509          * can and should check what it introduces.
2510          */
2511         if (diff_filespec_is_binary(two))
2512                 goto free_and_return;
2513         else {
2514                 /* Crazy xdl interfaces.. */
2515                 xpparam_t xpp;
2516                 xdemitconf_t xecfg;
2517
2518                 memset(&xpp, 0, sizeof(xpp));
2519                 memset(&xecfg, 0, sizeof(xecfg));
2520                 xecfg.ctxlen = 1; /* at least one context line */
2521                 xpp.flags = 0;
2522                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2523                               &xpp, &xecfg);
2524
2525                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2526                         struct emit_callback ecbdata;
2527                         int blank_at_eof;
2528
2529                         ecbdata.ws_rule = data.ws_rule;
2530                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2531                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2532
2533                         if (blank_at_eof) {
2534                                 static char *err;
2535                                 if (!err)
2536                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2537                                 fprintf(o->file, "%s:%d: %s.\n",
2538                                         data.filename, blank_at_eof, err);
2539                                 data.status = 1; /* report errors */
2540                         }
2541                 }
2542         }
2543  free_and_return:
2544         diff_free_filespec_data(one);
2545         diff_free_filespec_data(two);
2546         if (data.status)
2547                 DIFF_OPT_SET(o, CHECK_FAILED);
2548 }
2549
2550 struct diff_filespec *alloc_filespec(const char *path)
2551 {
2552         int namelen = strlen(path);
2553         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2554
2555         memset(spec, 0, sizeof(*spec));
2556         spec->path = (char *)(spec + 1);
2557         memcpy(spec->path, path, namelen+1);
2558         spec->count = 1;
2559         spec->is_binary = -1;
2560         return spec;
2561 }
2562
2563 void free_filespec(struct diff_filespec *spec)
2564 {
2565         if (!--spec->count) {
2566                 diff_free_filespec_data(spec);
2567                 free(spec);
2568         }
2569 }
2570
2571 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2572                    int sha1_valid, unsigned short mode)
2573 {
2574         if (mode) {
2575                 spec->mode = canon_mode(mode);
2576                 hashcpy(spec->sha1, sha1);
2577                 spec->sha1_valid = sha1_valid;
2578         }
2579 }
2580
2581 /*
2582  * Given a name and sha1 pair, if the index tells us the file in
2583  * the work tree has that object contents, return true, so that
2584  * prepare_temp_file() does not have to inflate and extract.
2585  */
2586 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2587 {
2588         struct cache_entry *ce;
2589         struct stat st;
2590         int pos, len;
2591
2592         /*
2593          * We do not read the cache ourselves here, because the
2594          * benchmark with my previous version that always reads cache
2595          * shows that it makes things worse for diff-tree comparing
2596          * two linux-2.6 kernel trees in an already checked out work
2597          * tree.  This is because most diff-tree comparisons deal with
2598          * only a small number of files, while reading the cache is
2599          * expensive for a large project, and its cost outweighs the
2600          * savings we get by not inflating the object to a temporary
2601          * file.  Practically, this code only helps when we are used
2602          * by diff-cache --cached, which does read the cache before
2603          * calling us.
2604          */
2605         if (!active_cache)
2606                 return 0;
2607
2608         /* We want to avoid the working directory if our caller
2609          * doesn't need the data in a normal file, this system
2610          * is rather slow with its stat/open/mmap/close syscalls,
2611          * and the object is contained in a pack file.  The pack
2612          * is probably already open and will be faster to obtain
2613          * the data through than the working directory.  Loose
2614          * objects however would tend to be slower as they need
2615          * to be individually opened and inflated.
2616          */
2617         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2618                 return 0;
2619
2620         len = strlen(name);
2621         pos = cache_name_pos(name, len);
2622         if (pos < 0)
2623                 return 0;
2624         ce = active_cache[pos];
2625
2626         /*
2627          * This is not the sha1 we are looking for, or
2628          * unreusable because it is not a regular file.
2629          */
2630         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2631                 return 0;
2632
2633         /*
2634          * If ce is marked as "assume unchanged", there is no
2635          * guarantee that work tree matches what we are looking for.
2636          */
2637         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2638                 return 0;
2639
2640         /*
2641          * If ce matches the file in the work tree, we can reuse it.
2642          */
2643         if (ce_uptodate(ce) ||
2644             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2645                 return 1;
2646
2647         return 0;
2648 }
2649
2650 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2651 {
2652         int len;
2653         char *data = xmalloc(100), *dirty = "";
2654
2655         /* Are we looking at the work tree? */
2656         if (s->dirty_submodule)
2657                 dirty = "-dirty";
2658
2659         len = snprintf(data, 100,
2660                        "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2661         s->data = data;
2662         s->size = len;
2663         s->should_free = 1;
2664         if (size_only) {
2665                 s->data = NULL;
2666                 free(data);
2667         }
2668         return 0;
2669 }
2670
2671 /*
2672  * While doing rename detection and pickaxe operation, we may need to
2673  * grab the data for the blob (or file) for our own in-core comparison.
2674  * diff_filespec has data and size fields for this purpose.
2675  */
2676 int diff_populate_filespec(struct diff_filespec *s, int size_only)
2677 {
2678         int err = 0;
2679         if (!DIFF_FILE_VALID(s))
2680                 die("internal error: asking to populate invalid file.");
2681         if (S_ISDIR(s->mode))
2682                 return -1;
2683
2684         if (s->data)
2685                 return 0;
2686
2687         if (size_only && 0 < s->size)
2688                 return 0;
2689
2690         if (S_ISGITLINK(s->mode))
2691                 return diff_populate_gitlink(s, size_only);
2692
2693         if (!s->sha1_valid ||
2694             reuse_worktree_file(s->path, s->sha1, 0)) {
2695                 struct strbuf buf = STRBUF_INIT;
2696                 struct stat st;
2697                 int fd;
2698
2699                 if (lstat(s->path, &st) < 0) {
2700                         if (errno == ENOENT) {
2701                         err_empty:
2702                                 err = -1;
2703                         empty:
2704                                 s->data = (char *)"";
2705                                 s->size = 0;
2706                                 return err;
2707                         }
2708                 }
2709                 s->size = xsize_t(st.st_size);
2710                 if (!s->size)
2711                         goto empty;
2712                 if (S_ISLNK(st.st_mode)) {
2713                         struct strbuf sb = STRBUF_INIT;
2714
2715                         if (strbuf_readlink(&sb, s->path, s->size))
2716                                 goto err_empty;
2717                         s->size = sb.len;
2718                         s->data = strbuf_detach(&sb, NULL);
2719                         s->should_free = 1;
2720                         return 0;
2721                 }
2722                 if (size_only)
2723                         return 0;
2724                 fd = open(s->path, O_RDONLY);
2725                 if (fd < 0)
2726                         goto err_empty;
2727                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2728                 close(fd);
2729                 s->should_munmap = 1;
2730
2731                 /*
2732                  * Convert from working tree format to canonical git format
2733                  */
2734                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2735                         size_t size = 0;
2736                         munmap(s->data, s->size);
2737                         s->should_munmap = 0;
2738                         s->data = strbuf_detach(&buf, &size);
2739                         s->size = size;
2740                         s->should_free = 1;
2741                 }
2742         }
2743         else {
2744                 enum object_type type;
2745                 if (size_only) {
2746                         type = sha1_object_info(s->sha1, &s->size);
2747                         if (type < 0)
2748                                 die("unable to read %s", sha1_to_hex(s->sha1));
2749                 } else {
2750                         s->data = read_sha1_file(s->sha1, &type, &s->size);
2751                         if (!s->data)
2752                                 die("unable to read %s", sha1_to_hex(s->sha1));
2753                         s->should_free = 1;
2754                 }
2755         }
2756         return 0;
2757 }
2758
2759 void diff_free_filespec_blob(struct diff_filespec *s)
2760 {
2761         if (s->should_free)
2762                 free(s->data);
2763         else if (s->should_munmap)
2764                 munmap(s->data, s->size);
2765
2766         if (s->should_free || s->should_munmap) {
2767                 s->should_free = s->should_munmap = 0;
2768                 s->data = NULL;
2769         }
2770 }
2771
2772 void diff_free_filespec_data(struct diff_filespec *s)
2773 {
2774         diff_free_filespec_blob(s);
2775         free(s->cnt_data);
2776         s->cnt_data = NULL;
2777 }
2778
2779 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2780                            void *blob,
2781                            unsigned long size,
2782                            const unsigned char *sha1,
2783                            int mode)
2784 {
2785         int fd;
2786         struct strbuf buf = STRBUF_INIT;
2787         struct strbuf template = STRBUF_INIT;
2788         char *path_dup = xstrdup(path);
2789         const char *base = basename(path_dup);
2790
2791         /* Generate "XXXXXX_basename.ext" */
2792         strbuf_addstr(&template, "XXXXXX_");
2793         strbuf_addstr(&template, base);
2794
2795         fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2796                         strlen(base) + 1);
2797         if (fd < 0)
2798                 die_errno("unable to create temp-file");
2799         if (convert_to_working_tree(path,
2800                         (const char *)blob, (size_t)size, &buf)) {
2801                 blob = buf.buf;
2802                 size = buf.len;
2803         }
2804         if (write_in_full(fd, blob, size) != size)
2805                 die_errno("unable to write temp-file");
2806         close(fd);
2807         temp->name = temp->tmp_path;
2808         strcpy(temp->hex, sha1_to_hex(sha1));
2809         temp->hex[40] = 0;
2810         sprintf(temp->mode, "%06o", mode);
2811         strbuf_release(&buf);
2812         strbuf_release(&template);
2813         free(path_dup);
2814 }
2815
2816 static struct diff_tempfile *prepare_temp_file(const char *name,
2817                 struct diff_filespec *one)
2818 {
2819         struct diff_tempfile *temp = claim_diff_tempfile();
2820
2821         if (!DIFF_FILE_VALID(one)) {
2822         not_a_valid_file:
2823                 /* A '-' entry produces this for file-2, and
2824                  * a '+' entry produces this for file-1.
2825                  */
2826                 temp->name = "/dev/null";
2827                 strcpy(temp->hex, ".");
2828                 strcpy(temp->mode, ".");
2829                 return temp;
2830         }
2831
2832         if (!remove_tempfile_installed) {
2833                 atexit(remove_tempfile);
2834                 sigchain_push_common(remove_tempfile_on_signal);
2835                 remove_tempfile_installed = 1;
2836         }
2837
2838         if (!one->sha1_valid ||
2839             reuse_worktree_file(name, one->sha1, 1)) {
2840                 struct stat st;
2841                 if (lstat(name, &st) < 0) {
2842                         if (errno == ENOENT)
2843                                 goto not_a_valid_file;
2844                         die_errno("stat(%s)", name);
2845                 }
2846                 if (S_ISLNK(st.st_mode)) {
2847                         struct strbuf sb = STRBUF_INIT;
2848                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
2849                                 die_errno("readlink(%s)", name);
2850                         prep_temp_blob(name, temp, sb.buf, sb.len,
2851                                        (one->sha1_valid ?
2852                                         one->sha1 : null_sha1),
2853                                        (one->sha1_valid ?
2854                                         one->mode : S_IFLNK));
2855                         strbuf_release(&sb);
2856                 }
2857                 else {
2858                         /* we can borrow from the file in the work tree */
2859                         temp->name = name;
2860                         if (!one->sha1_valid)
2861                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
2862                         else
2863                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
2864                         /* Even though we may sometimes borrow the
2865                          * contents from the work tree, we always want
2866                          * one->mode.  mode is trustworthy even when
2867                          * !(one->sha1_valid), as long as
2868                          * DIFF_FILE_VALID(one).
2869                          */
2870                         sprintf(temp->mode, "%06o", one->mode);
2871                 }
2872                 return temp;
2873         }
2874         else {
2875                 if (diff_populate_filespec(one, 0))
2876                         die("cannot read data blob for %s", one->path);
2877                 prep_temp_blob(name, temp, one->data, one->size,
2878                                one->sha1, one->mode);
2879         }
2880         return temp;
2881 }
2882
2883 /* An external diff command takes:
2884  *
2885  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2886  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2887  *
2888  */
2889 static void run_external_diff(const char *pgm,
2890                               const char *name,
2891                               const char *other,
2892                               struct diff_filespec *one,
2893                               struct diff_filespec *two,
2894                               const char *xfrm_msg,
2895                               int complete_rewrite)
2896 {
2897         const char *spawn_arg[10];
2898         int retval;
2899         const char **arg = &spawn_arg[0];
2900
2901         if (one && two) {
2902                 struct diff_tempfile *temp_one, *temp_two;
2903                 const char *othername = (other ? other : name);
2904                 temp_one = prepare_temp_file(name, one);
2905                 temp_two = prepare_temp_file(othername, two);
2906                 *arg++ = pgm;
2907                 *arg++ = name;
2908                 *arg++ = temp_one->name;
2909                 *arg++ = temp_one->hex;
2910                 *arg++ = temp_one->mode;
2911                 *arg++ = temp_two->name;
2912                 *arg++ = temp_two->hex;
2913                 *arg++ = temp_two->mode;
2914                 if (other) {
2915                         *arg++ = other;
2916                         *arg++ = xfrm_msg;
2917                 }
2918         } else {
2919                 *arg++ = pgm;
2920                 *arg++ = name;
2921         }
2922         *arg = NULL;
2923         fflush(NULL);
2924         retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2925         remove_tempfile();
2926         if (retval) {
2927                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
2928                 exit(1);
2929         }
2930 }
2931
2932 static int similarity_index(struct diff_filepair *p)
2933 {
2934         return p->score * 100 / MAX_SCORE;
2935 }
2936
2937 static void fill_metainfo(struct strbuf *msg,
2938                           const char *name,
2939                           const char *other,
2940                           struct diff_filespec *one,
2941                           struct diff_filespec *two,
2942                           struct diff_options *o,
2943                           struct diff_filepair *p,
2944                           int *must_show_header,
2945                           int use_color)
2946 {
2947         const char *set = diff_get_color(use_color, DIFF_METAINFO);
2948         const char *reset = diff_get_color(use_color, DIFF_RESET);
2949         const char *line_prefix = diff_line_prefix(o);
2950
2951         *must_show_header = 1;
2952         strbuf_init(msg, PATH_MAX * 2 + 300);
2953         switch (p->status) {
2954         case DIFF_STATUS_COPIED:
2955                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2956                             line_prefix, set, similarity_index(p));
2957                 strbuf_addf(msg, "%s\n%s%scopy from ",
2958                             reset,  line_prefix, set);
2959                 quote_c_style(name, msg, NULL, 0);
2960                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2961                 quote_c_style(other, msg, NULL, 0);
2962                 strbuf_addf(msg, "%s\n", reset);
2963                 break;
2964         case DIFF_STATUS_RENAMED:
2965                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
2966                             line_prefix, set, similarity_index(p));
2967                 strbuf_addf(msg, "%s\n%s%srename from ",
2968                             reset, line_prefix, set);
2969                 quote_c_style(name, msg, NULL, 0);
2970                 strbuf_addf(msg, "%s\n%s%srename to ",
2971                             reset, line_prefix, set);
2972                 quote_c_style(other, msg, NULL, 0);
2973                 strbuf_addf(msg, "%s\n", reset);
2974                 break;
2975         case DIFF_STATUS_MODIFIED:
2976                 if (p->score) {
2977                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2978                                     line_prefix,
2979                                     set, similarity_index(p), reset);
2980                         break;
2981                 }
2982                 /* fallthru */
2983         default:
2984                 *must_show_header = 0;
2985         }
2986         if (one && two && hashcmp(one->sha1, two->sha1)) {
2987                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2988
2989                 if (DIFF_OPT_TST(o, BINARY)) {
2990                         mmfile_t mf;
2991                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2992                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2993                                 abbrev = 40;
2994                 }
2995                 strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2996                             find_unique_abbrev(one->sha1, abbrev));
2997                 strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2998                 if (one->mode == two->mode)
2999                         strbuf_addf(msg, " %06o", one->mode);
3000                 strbuf_addf(msg, "%s\n", reset);
3001         }
3002 }
3003
3004 static void run_diff_cmd(const char *pgm,
3005                          const char *name,
3006                          const char *other,
3007                          const char *attr_path,
3008                          struct diff_filespec *one,
3009                          struct diff_filespec *two,
3010                          struct strbuf *msg,
3011                          struct diff_options *o,
3012                          struct diff_filepair *p)
3013 {
3014         const char *xfrm_msg = NULL;
3015         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3016         int must_show_header = 0;
3017
3018
3019         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3020                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3021                 if (drv && drv->external)
3022                         pgm = drv->external;
3023         }
3024
3025         if (msg) {
3026                 /*
3027                  * don't use colors when the header is intended for an
3028                  * external diff driver
3029                  */
3030                 fill_metainfo(msg, name, other, one, two, o, p,
3031                               &must_show_header,
3032                               want_color(o->use_color) && !pgm);
3033                 xfrm_msg = msg->len ? msg->buf : NULL;
3034         }
3035
3036         if (pgm) {
3037                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3038                                   complete_rewrite);
3039                 return;
3040         }
3041         if (one && two)
3042                 builtin_diff(name, other ? other : name,
3043                              one, two, xfrm_msg, must_show_header,
3044                              o, complete_rewrite);
3045         else
3046                 fprintf(o->file, "* Unmerged path %s\n", name);
3047 }
3048
3049 static void diff_fill_sha1_info(struct diff_filespec *one)
3050 {
3051         if (DIFF_FILE_VALID(one)) {
3052                 if (!one->sha1_valid) {
3053                         struct stat st;
3054                         if (one->is_stdin) {
3055                                 hashcpy(one->sha1, null_sha1);
3056                                 return;
3057                         }
3058                         if (lstat(one->path, &st) < 0)
3059                                 die_errno("stat '%s'", one->path);
3060                         if (index_path(one->sha1, one->path, &st, 0))
3061                                 die("cannot hash %s", one->path);
3062                 }
3063         }
3064         else
3065                 hashclr(one->sha1);
3066 }
3067
3068 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3069 {
3070         /* Strip the prefix but do not molest /dev/null and absolute paths */
3071         if (*namep && **namep != '/') {
3072                 *namep += prefix_length;
3073                 if (**namep == '/')
3074                         ++*namep;
3075         }
3076         if (*otherp && **otherp != '/') {
3077                 *otherp += prefix_length;
3078                 if (**otherp == '/')
3079                         ++*otherp;
3080         }
3081 }
3082
3083 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3084 {
3085         const char *pgm = external_diff();
3086         struct strbuf msg;
3087         struct diff_filespec *one = p->one;
3088         struct diff_filespec *two = p->two;
3089         const char *name;
3090         const char *other;
3091         const char *attr_path;
3092
3093         name  = p->one->path;
3094         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3095         attr_path = name;
3096         if (o->prefix_length)
3097                 strip_prefix(o->prefix_length, &name, &other);
3098
3099         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3100                 pgm = NULL;
3101
3102         if (DIFF_PAIR_UNMERGED(p)) {
3103                 run_diff_cmd(pgm, name, NULL, attr_path,
3104                              NULL, NULL, NULL, o, p);
3105                 return;
3106         }
3107
3108         diff_fill_sha1_info(one);
3109         diff_fill_sha1_info(two);
3110
3111         if (!pgm &&
3112             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3113             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3114                 /*
3115                  * a filepair that changes between file and symlink
3116                  * needs to be split into deletion and creation.
3117                  */
3118                 struct diff_filespec *null = alloc_filespec(two->path);
3119                 run_diff_cmd(NULL, name, other, attr_path,
3120                              one, null, &msg, o, p);
3121                 free(null);
3122                 strbuf_release(&msg);
3123
3124                 null = alloc_filespec(one->path);
3125                 run_diff_cmd(NULL, name, other, attr_path,
3126                              null, two, &msg, o, p);
3127                 free(null);
3128         }
3129         else
3130                 run_diff_cmd(pgm, name, other, attr_path,
3131                              one, two, &msg, o, p);
3132
3133         strbuf_release(&msg);
3134 }
3135
3136 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3137                          struct diffstat_t *diffstat)
3138 {
3139         const char *name;
3140         const char *other;
3141
3142         if (DIFF_PAIR_UNMERGED(p)) {
3143                 /* unmerged */
3144                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3145                 return;
3146         }
3147
3148         name = p->one->path;
3149         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3150
3151         if (o->prefix_length)
3152                 strip_prefix(o->prefix_length, &name, &other);
3153
3154         diff_fill_sha1_info(p->one);
3155         diff_fill_sha1_info(p->two);
3156
3157         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3158 }
3159
3160 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3161 {
3162         const char *name;
3163         const char *other;
3164         const char *attr_path;
3165
3166         if (DIFF_PAIR_UNMERGED(p)) {
3167                 /* unmerged */
3168                 return;
3169         }
3170
3171         name = p->one->path;
3172         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3173         attr_path = other ? other : name;
3174
3175         if (o->prefix_length)
3176                 strip_prefix(o->prefix_length, &name, &other);
3177
3178         diff_fill_sha1_info(p->one);
3179         diff_fill_sha1_info(p->two);
3180
3181         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3182 }
3183
3184 void diff_setup(struct diff_options *options)
3185 {
3186         memcpy(options, &default_diff_options, sizeof(*options));
3187
3188         options->file = stdout;
3189
3190         options->line_termination = '\n';
3191         options->break_opt = -1;
3192         options->rename_limit = -1;
3193         options->dirstat_permille = diff_dirstat_permille_default;
3194         options->context = diff_context_default;
3195         DIFF_OPT_SET(options, RENAME_EMPTY);
3196
3197         options->change = diff_change;
3198         options->add_remove = diff_addremove;
3199         options->use_color = diff_use_color_default;
3200         options->detect_rename = diff_detect_rename_default;
3201         options->xdl_opts |= diff_algorithm;
3202
3203         if (diff_no_prefix) {
3204                 options->a_prefix = options->b_prefix = "";
3205         } else if (!diff_mnemonic_prefix) {
3206                 options->a_prefix = "a/";
3207                 options->b_prefix = "b/";
3208         }
3209 }
3210
3211 void diff_setup_done(struct diff_options *options)
3212 {
3213         int count = 0;
3214
3215         if (options->output_format & DIFF_FORMAT_NAME)
3216                 count++;
3217         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3218                 count++;
3219         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3220                 count++;
3221         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3222                 count++;
3223         if (count > 1)
3224                 die("--name-only, --name-status, --check and -s are mutually exclusive");
3225
3226         /*
3227          * Most of the time we can say "there are changes"
3228          * only by checking if there are changed paths, but
3229          * --ignore-whitespace* options force us to look
3230          * inside contents.
3231          */
3232
3233         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3234             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3235             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3236                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3237         else
3238                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3239
3240         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3241                 options->detect_rename = DIFF_DETECT_COPY;
3242
3243         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3244                 options->prefix = NULL;
3245         if (options->prefix)
3246                 options->prefix_length = strlen(options->prefix);
3247         else
3248                 options->prefix_length = 0;
3249
3250         if (options->output_format & (DIFF_FORMAT_NAME |
3251                                       DIFF_FORMAT_NAME_STATUS |
3252                                       DIFF_FORMAT_CHECKDIFF |
3253                                       DIFF_FORMAT_NO_OUTPUT))
3254                 options->output_format &= ~(DIFF_FORMAT_RAW |
3255                                             DIFF_FORMAT_NUMSTAT |
3256                                             DIFF_FORMAT_DIFFSTAT |
3257                                             DIFF_FORMAT_SHORTSTAT |
3258                                             DIFF_FORMAT_DIRSTAT |
3259                                             DIFF_FORMAT_SUMMARY |
3260                                             DIFF_FORMAT_PATCH);
3261
3262         /*
3263          * These cases always need recursive; we do not drop caller-supplied
3264          * recursive bits for other formats here.
3265          */
3266         if (options->output_format & (DIFF_FORMAT_PATCH |
3267                                       DIFF_FORMAT_NUMSTAT |
3268                                       DIFF_FORMAT_DIFFSTAT |
3269                                       DIFF_FORMAT_SHORTSTAT |
3270                                       DIFF_FORMAT_DIRSTAT |
3271                                       DIFF_FORMAT_SUMMARY |
3272                                       DIFF_FORMAT_CHECKDIFF))
3273                 DIFF_OPT_SET(options, RECURSIVE);
3274         /*
3275          * Also pickaxe would not work very well if you do not say recursive
3276          */
3277         if (options->pickaxe)
3278                 DIFF_OPT_SET(options, RECURSIVE);
3279         /*
3280          * When patches are generated, submodules diffed against the work tree
3281          * must be checked for dirtiness too so it can be shown in the output
3282          */
3283         if (options->output_format & DIFF_FORMAT_PATCH)
3284                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3285
3286         if (options->detect_rename && options->rename_limit < 0)
3287                 options->rename_limit = diff_rename_limit_default;
3288         if (options->setup & DIFF_SETUP_USE_CACHE) {
3289                 if (!active_cache)
3290                         /* read-cache does not die even when it fails
3291                          * so it is safe for us to do this here.  Also
3292                          * it does not smudge active_cache or active_nr
3293                          * when it fails, so we do not have to worry about
3294                          * cleaning it up ourselves either.
3295                          */
3296                         read_cache();
3297         }
3298         if (options->abbrev <= 0 || 40 < options->abbrev)
3299                 options->abbrev = 40; /* full */
3300
3301         /*
3302          * It does not make sense to show the first hit we happened
3303          * to have found.  It does not make sense not to return with
3304          * exit code in such a case either.
3305          */
3306         if (DIFF_OPT_TST(options, QUICK)) {
3307                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3308                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3309         }
3310 }
3311
3312 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3313 {
3314         char c, *eq;
3315         int len;
3316
3317         if (*arg != '-')
3318                 return 0;
3319         c = *++arg;
3320         if (!c)
3321                 return 0;
3322         if (c == arg_short) {
3323                 c = *++arg;
3324                 if (!c)
3325                         return 1;
3326                 if (val && isdigit(c)) {
3327                         char *end;
3328                         int n = strtoul(arg, &end, 10);
3329                         if (*end)
3330                                 return 0;
3331                         *val = n;
3332                         return 1;
3333                 }
3334                 return 0;
3335         }
3336         if (c != '-')
3337                 return 0;
3338         arg++;
3339         eq = strchr(arg, '=');
3340         if (eq)
3341                 len = eq - arg;
3342         else
3343                 len = strlen(arg);
3344         if (!len || strncmp(arg, arg_long, len))
3345                 return 0;
3346         if (eq) {
3347                 int n;
3348                 char *end;
3349                 if (!isdigit(*++eq))
3350                         return 0;
3351                 n = strtoul(eq, &end, 10);
3352                 if (*end)
3353                         return 0;
3354                 *val = n;
3355         }
3356         return 1;
3357 }
3358
3359 static int diff_scoreopt_parse(const char *opt);
3360
3361 static inline int short_opt(char opt, const char **argv,
3362                             const char **optarg)
3363 {
3364         const char *arg = argv[0];
3365         if (arg[0] != '-' || arg[1] != opt)
3366                 return 0;
3367         if (arg[2] != '\0') {
3368                 *optarg = arg + 2;
3369                 return 1;
3370         }
3371         if (!argv[1])
3372                 die("Option '%c' requires a value", opt);
3373         *optarg = argv[1];
3374         return 2;
3375 }
3376
3377 int parse_long_opt(const char *opt, const char **argv,
3378                    const char **optarg)
3379 {
3380         const char *arg = argv[0];
3381         if (arg[0] != '-' || arg[1] != '-')
3382                 return 0;
3383         arg += strlen("--");
3384         if (prefixcmp(arg, opt))
3385                 return 0;
3386         arg += strlen(opt);
3387         if (*arg == '=') { /* sticked form: --option=value */
3388                 *optarg = arg + 1;
3389                 return 1;
3390         }
3391         if (*arg != '\0')
3392                 return 0;
3393         /* separate form: --option value */
3394         if (!argv[1])
3395                 die("Option '--%s' requires a value", opt);
3396         *optarg = argv[1];
3397         return 2;
3398 }
3399
3400 static int stat_opt(struct diff_options *options, const char **av)
3401 {
3402         const char *arg = av[0];
3403         char *end;
3404         int width = options->stat_width;
3405         int name_width = options->stat_name_width;
3406         int graph_width = options->stat_graph_width;
3407         int count = options->stat_count;
3408         int argcount = 1;
3409
3410         arg += strlen("--stat");
3411         end = (char *)arg;
3412
3413         switch (*arg) {
3414         case '-':
3415                 if (!prefixcmp(arg, "-width")) {
3416                         arg += strlen("-width");
3417                         if (*arg == '=')
3418                                 width = strtoul(arg + 1, &end, 10);
3419                         else if (!*arg && !av[1])
3420                                 die("Option '--stat-width' requires a value");
3421                         else if (!*arg) {
3422                                 width = strtoul(av[1], &end, 10);
3423                                 argcount = 2;
3424                         }
3425                 } else if (!prefixcmp(arg, "-name-width")) {
3426                         arg += strlen("-name-width");
3427                         if (*arg == '=')
3428                                 name_width = strtoul(arg + 1, &end, 10);
3429                         else if (!*arg && !av[1])
3430                                 die("Option '--stat-name-width' requires a value");
3431                         else if (!*arg) {
3432                                 name_width = strtoul(av[1], &end, 10);
3433                                 argcount = 2;
3434                         }
3435                 } else if (!prefixcmp(arg, "-graph-width")) {
3436                         arg += strlen("-graph-width");
3437                         if (*arg == '=')
3438                                 graph_width = strtoul(arg + 1, &end, 10);
3439                         else if (!*arg && !av[1])
3440                                 die("Option '--stat-graph-width' requires a value");
3441                         else if (!*arg) {
3442                                 graph_width = strtoul(av[1], &end, 10);
3443                                 argcount = 2;
3444                         }
3445                 } else if (!prefixcmp(arg, "-count")) {
3446                         arg += strlen("-count");
3447                         if (*arg == '=')
3448                                 count = strtoul(arg + 1, &end, 10);
3449                         else if (!*arg && !av[1])
3450                                 die("Option '--stat-count' requires a value");
3451                         else if (!*arg) {
3452                                 count = strtoul(av[1], &end, 10);
3453                                 argcount = 2;
3454                         }
3455                 }
3456                 break;
3457         case '=':
3458                 width = strtoul(arg+1, &end, 10);
3459                 if (*end == ',')
3460                         name_width = strtoul(end+1, &end, 10);
3461                 if (*end == ',')
3462                         count = strtoul(end+1, &end, 10);
3463         }
3464
3465         /* Important! This checks all the error cases! */
3466         if (*end)
3467                 return 0;
3468         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3469         options->stat_name_width = name_width;
3470         options->stat_graph_width = graph_width;
3471         options->stat_width = width;
3472         options->stat_count = count;
3473         return argcount;
3474 }
3475
3476 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3477 {
3478         struct strbuf errmsg = STRBUF_INIT;
3479         if (parse_dirstat_params(options, params, &errmsg))
3480                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3481                     errmsg.buf);
3482         strbuf_release(&errmsg);
3483         /*
3484          * The caller knows a dirstat-related option is given from the command
3485          * line; allow it to say "return this_function();"
3486          */
3487         options->output_format |= DIFF_FORMAT_DIRSTAT;
3488         return 1;
3489 }
3490
3491 static int parse_submodule_opt(struct diff_options *options, const char *value)
3492 {
3493         if (parse_submodule_params(options, value))
3494                 die(_("Failed to parse --submodule option parameter: '%s'"),
3495                         value);
3496         return 1;
3497 }
3498
3499 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3500 {
3501         const char *arg = av[0];
3502         const char *optarg;
3503         int argcount;
3504
3505         /* Output format options */
3506         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3507                 options->output_format |= DIFF_FORMAT_PATCH;
3508         else if (opt_arg(arg, 'U', "unified", &options->context))
3509                 options->output_format |= DIFF_FORMAT_PATCH;
3510         else if (!strcmp(arg, "--raw"))
3511                 options->output_format |= DIFF_FORMAT_RAW;
3512         else if (!strcmp(arg, "--patch-with-raw"))
3513                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3514         else if (!strcmp(arg, "--numstat"))
3515                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3516         else if (!strcmp(arg, "--shortstat"))
3517                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3518         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3519                 return parse_dirstat_opt(options, "");
3520         else if (!prefixcmp(arg, "-X"))
3521                 return parse_dirstat_opt(options, arg + 2);
3522         else if (!prefixcmp(arg, "--dirstat="))
3523                 return parse_dirstat_opt(options, arg + 10);
3524         else if (!strcmp(arg, "--cumulative"))
3525                 return parse_dirstat_opt(options, "cumulative");
3526         else if (!strcmp(arg, "--dirstat-by-file"))
3527                 return parse_dirstat_opt(options, "files");
3528         else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3529                 parse_dirstat_opt(options, "files");
3530                 return parse_dirstat_opt(options, arg + 18);
3531         }
3532         else if (!strcmp(arg, "--check"))
3533                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3534         else if (!strcmp(arg, "--summary"))
3535                 options->output_format |= DIFF_FORMAT_SUMMARY;
3536         else if (!strcmp(arg, "--patch-with-stat"))
3537                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3538         else if (!strcmp(arg, "--name-only"))
3539                 options->output_format |= DIFF_FORMAT_NAME;
3540         else if (!strcmp(arg, "--name-status"))
3541                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3542         else if (!strcmp(arg, "-s"))
3543                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3544         else if (!prefixcmp(arg, "--stat"))
3545                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3546                 return stat_opt(options, av);
3547
3548         /* renames options */
3549         else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3550                  !strcmp(arg, "--break-rewrites")) {
3551                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3552                         return error("invalid argument to -B: %s", arg+2);
3553         }
3554         else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3555                  !strcmp(arg, "--find-renames")) {
3556                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3557                         return error("invalid argument to -M: %s", arg+2);
3558                 options->detect_rename = DIFF_DETECT_RENAME;
3559         }
3560         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3561                 options->irreversible_delete = 1;
3562         }
3563         else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3564                  !strcmp(arg, "--find-copies")) {
3565                 if (options->detect_rename == DIFF_DETECT_COPY)
3566                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3567                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3568                         return error("invalid argument to -C: %s", arg+2);
3569                 options->detect_rename = DIFF_DETECT_COPY;
3570         }
3571         else if (!strcmp(arg, "--no-renames"))
3572                 options->detect_rename = 0;
3573         else if (!strcmp(arg, "--rename-empty"))
3574                 DIFF_OPT_SET(options, RENAME_EMPTY);
3575         else if (!strcmp(arg, "--no-rename-empty"))
3576                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3577         else if (!strcmp(arg, "--relative"))
3578                 DIFF_OPT_SET(options, RELATIVE_NAME);
3579         else if (!prefixcmp(arg, "--relative=")) {
3580                 DIFF_OPT_SET(options, RELATIVE_NAME);
3581                 options->prefix = arg + 11;
3582         }
3583
3584         /* xdiff options */
3585         else if (!strcmp(arg, "--minimal"))
3586                 DIFF_XDL_SET(options, NEED_MINIMAL);
3587         else if (!strcmp(arg, "--no-minimal"))
3588                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3589         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3590                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3591         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3592                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3593         else if (!strcmp(arg, "--ignore-space-at-eol"))
3594                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3595         else if (!strcmp(arg, "--patience"))
3596                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3597         else if (!strcmp(arg, "--histogram"))
3598                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3599         else if (!prefixcmp(arg, "--diff-algorithm=")) {
3600                 long value = parse_algorithm_value(arg+17);
3601                 if (value < 0)
3602                         return error("option diff-algorithm accepts \"myers\", "
3603                                      "\"minimal\", \"patience\" and \"histogram\"");
3604                 /* clear out previous settings */
3605                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3606                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3607                 options->xdl_opts |= value;
3608         }
3609
3610         /* flags options */
3611         else if (!strcmp(arg, "--binary")) {
3612                 options->output_format |= DIFF_FORMAT_PATCH;
3613                 DIFF_OPT_SET(options, BINARY);
3614         }
3615         else if (!strcmp(arg, "--full-index"))
3616                 DIFF_OPT_SET(options, FULL_INDEX);
3617         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3618                 DIFF_OPT_SET(options, TEXT);
3619         else if (!strcmp(arg, "-R"))
3620                 DIFF_OPT_SET(options, REVERSE_DIFF);
3621         else if (!strcmp(arg, "--find-copies-harder"))
3622                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3623         else if (!strcmp(arg, "--follow"))
3624                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3625         else if (!strcmp(arg, "--no-follow"))
3626                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3627         else if (!strcmp(arg, "--color"))
3628                 options->use_color = 1;
3629         else if (!prefixcmp(arg, "--color=")) {
3630                 int value = git_config_colorbool(NULL, arg+8);
3631                 if (value < 0)
3632                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3633                 options->use_color = value;
3634         }
3635         else if (!strcmp(arg, "--no-color"))
3636                 options->use_color = 0;
3637         else if (!strcmp(arg, "--color-words")) {
3638                 options->use_color = 1;
3639                 options->word_diff = DIFF_WORDS_COLOR;
3640         }
3641         else if (!prefixcmp(arg, "--color-words=")) {
3642                 options->use_color = 1;
3643                 options->word_diff = DIFF_WORDS_COLOR;
3644                 options->word_regex = arg + 14;
3645         }
3646         else if (!strcmp(arg, "--word-diff")) {
3647                 if (options->word_diff == DIFF_WORDS_NONE)
3648                         options->word_diff = DIFF_WORDS_PLAIN;
3649         }
3650         else if (!prefixcmp(arg, "--word-diff=")) {
3651                 const char *type = arg + 12;
3652                 if (!strcmp(type, "plain"))
3653                         options->word_diff = DIFF_WORDS_PLAIN;
3654                 else if (!strcmp(type, "color")) {
3655                         options->use_color = 1;
3656                         options->word_diff = DIFF_WORDS_COLOR;
3657                 }
3658                 else if (!strcmp(type, "porcelain"))
3659                         options->word_diff = DIFF_WORDS_PORCELAIN;
3660                 else if (!strcmp(type, "none"))
3661                         options->word_diff = DIFF_WORDS_NONE;
3662                 else
3663                         die("bad --word-diff argument: %s", type);
3664         }
3665         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3666                 if (options->word_diff == DIFF_WORDS_NONE)
3667                         options->word_diff = DIFF_WORDS_PLAIN;
3668                 options->word_regex = optarg;
3669                 return argcount;
3670         }
3671         else if (!strcmp(arg, "--exit-code"))
3672                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3673         else if (!strcmp(arg, "--quiet"))
3674                 DIFF_OPT_SET(options, QUICK);
3675         else if (!strcmp(arg, "--ext-diff"))
3676                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3677         else if (!strcmp(arg, "--no-ext-diff"))
3678                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3679         else if (!strcmp(arg, "--textconv"))
3680                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3681         else if (!strcmp(arg, "--no-textconv"))
3682                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3683         else if (!strcmp(arg, "--ignore-submodules")) {
3684                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3685                 handle_ignore_submodules_arg(options, "all");
3686         } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3687                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3688                 handle_ignore_submodules_arg(options, arg + 20);
3689         } else if (!strcmp(arg, "--submodule"))
3690                 DIFF_OPT_SET(options, SUBMODULE_LOG);
3691         else if (!prefixcmp(arg, "--submodule="))
3692                 return parse_submodule_opt(options, arg + 12);
3693
3694         /* misc options */
3695         else if (!strcmp(arg, "-z"))
3696                 options->line_termination = 0;
3697         else if ((argcount = short_opt('l', av, &optarg))) {
3698                 options->rename_limit = strtoul(optarg, NULL, 10);
3699                 return argcount;
3700         }
3701         else if ((argcount = short_opt('S', av, &optarg))) {
3702                 options->pickaxe = optarg;
3703                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3704                 return argcount;
3705         } else if ((argcount = short_opt('G', av, &optarg))) {
3706                 options->pickaxe = optarg;
3707                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3708                 return argcount;
3709         }
3710         else if (!strcmp(arg, "--pickaxe-all"))
3711                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3712         else if (!strcmp(arg, "--pickaxe-regex"))
3713                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3714         else if ((argcount = short_opt('O', av, &optarg))) {
3715                 options->orderfile = optarg;
3716                 return argcount;
3717         }
3718         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3719                 options->filter = optarg;
3720                 return argcount;
3721         }
3722         else if (!strcmp(arg, "--abbrev"))
3723                 options->abbrev = DEFAULT_ABBREV;
3724         else if (!prefixcmp(arg, "--abbrev=")) {
3725                 options->abbrev = strtoul(arg + 9, NULL, 10);
3726                 if (options->abbrev < MINIMUM_ABBREV)
3727                         options->abbrev = MINIMUM_ABBREV;
3728                 else if (40 < options->abbrev)
3729                         options->abbrev = 40;
3730         }
3731         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3732                 options->a_prefix = optarg;
3733                 return argcount;
3734         }
3735         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3736                 options->b_prefix = optarg;
3737                 return argcount;
3738         }
3739         else if (!strcmp(arg, "--no-prefix"))
3740                 options->a_prefix = options->b_prefix = "";
3741         else if (opt_arg(arg, '\0', "inter-hunk-context",
3742                          &options->interhunkcontext))
3743                 ;
3744         else if (!strcmp(arg, "-W"))
3745                 DIFF_OPT_SET(options, FUNCCONTEXT);
3746         else if (!strcmp(arg, "--function-context"))
3747                 DIFF_OPT_SET(options, FUNCCONTEXT);
3748         else if (!strcmp(arg, "--no-function-context"))
3749                 DIFF_OPT_CLR(options, FUNCCONTEXT);
3750         else if ((argcount = parse_long_opt("output", av, &optarg))) {
3751                 options->file = fopen(optarg, "w");
3752                 if (!options->file)
3753                         die_errno("Could not open '%s'", optarg);
3754                 options->close_file = 1;
3755                 return argcount;
3756         } else
3757                 return 0;
3758         return 1;
3759 }
3760
3761 int parse_rename_score(const char **cp_p)
3762 {
3763         unsigned long num, scale;
3764         int ch, dot;
3765         const char *cp = *cp_p;
3766
3767         num = 0;
3768         scale = 1;
3769         dot = 0;
3770         for (;;) {
3771                 ch = *cp;
3772                 if ( !dot && ch == '.' ) {
3773                         scale = 1;
3774                         dot = 1;
3775                 } else if ( ch == '%' ) {
3776                         scale = dot ? scale*100 : 100;
3777                         cp++;   /* % is always at the end */
3778                         break;
3779                 } else if ( ch >= '0' && ch <= '9' ) {
3780                         if ( scale < 100000 ) {
3781                                 scale *= 10;
3782                                 num = (num*10) + (ch-'0');
3783                         }
3784                 } else {
3785                         break;
3786                 }
3787                 cp++;
3788         }
3789         *cp_p = cp;
3790
3791         /* user says num divided by scale and we say internally that
3792          * is MAX_SCORE * num / scale.
3793          */
3794         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3795 }
3796
3797 static int diff_scoreopt_parse(const char *opt)
3798 {
3799         int opt1, opt2, cmd;
3800
3801         if (*opt++ != '-')
3802                 return -1;
3803         cmd = *opt++;
3804         if (cmd == '-') {
3805                 /* convert the long-form arguments into short-form versions */
3806                 if (!prefixcmp(opt, "break-rewrites")) {
3807                         opt += strlen("break-rewrites");
3808                         if (*opt == 0 || *opt++ == '=')
3809                                 cmd = 'B';
3810                 } else if (!prefixcmp(opt, "find-copies")) {
3811                         opt += strlen("find-copies");
3812                         if (*opt == 0 || *opt++ == '=')
3813                                 cmd = 'C';
3814                 } else if (!prefixcmp(opt, "find-renames")) {
3815                         opt += strlen("find-renames");
3816                         if (*opt == 0 || *opt++ == '=')
3817                                 cmd = 'M';
3818                 }
3819         }
3820         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3821                 return -1; /* that is not a -M, -C nor -B option */
3822
3823         opt1 = parse_rename_score(&opt);
3824         if (cmd != 'B')
3825                 opt2 = 0;
3826         else {
3827                 if (*opt == 0)
3828                         opt2 = 0;
3829                 else if (*opt != '/')
3830                         return -1; /* we expect -B80/99 or -B80 */
3831                 else {
3832                         opt++;
3833                         opt2 = parse_rename_score(&opt);
3834                 }
3835         }
3836         if (*opt != 0)
3837                 return -1;
3838         return opt1 | (opt2 << 16);
3839 }
3840
3841 struct diff_queue_struct diff_queued_diff;
3842
3843 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3844 {
3845         if (queue->alloc <= queue->nr) {
3846                 queue->alloc = alloc_nr(queue->alloc);
3847                 queue->queue = xrealloc(queue->queue,
3848                                         sizeof(dp) * queue->alloc);
3849         }
3850         queue->queue[queue->nr++] = dp;
3851 }
3852
3853 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3854                                  struct diff_filespec *one,
3855                                  struct diff_filespec *two)
3856 {
3857         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3858         dp->one = one;
3859         dp->two = two;
3860         if (queue)
3861                 diff_q(queue, dp);
3862         return dp;
3863 }
3864
3865 void diff_free_filepair(struct diff_filepair *p)
3866 {
3867         free_filespec(p->one);
3868         free_filespec(p->two);
3869         free(p);
3870 }
3871
3872 /* This is different from find_unique_abbrev() in that
3873  * it stuffs the result with dots for alignment.
3874  */
3875 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3876 {
3877         int abblen;
3878         const char *abbrev;
3879         if (len == 40)
3880                 return sha1_to_hex(sha1);
3881
3882         abbrev = find_unique_abbrev(sha1, len);
3883         abblen = strlen(abbrev);
3884         if (abblen < 37) {
3885                 static char hex[41];
3886                 if (len < abblen && abblen <= len + 2)
3887                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3888                 else
3889                         sprintf(hex, "%s...", abbrev);
3890                 return hex;
3891         }
3892         return sha1_to_hex(sha1);
3893 }
3894
3895 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3896 {
3897         int line_termination = opt->line_termination;
3898         int inter_name_termination = line_termination ? '\t' : '\0';
3899
3900         fprintf(opt->file, "%s", diff_line_prefix(opt));
3901         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3902                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3903                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
3904                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3905         }
3906         if (p->score) {
3907                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3908                         inter_name_termination);
3909         } else {
3910                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3911         }
3912
3913         if (p->status == DIFF_STATUS_COPIED ||
3914             p->status == DIFF_STATUS_RENAMED) {
3915                 const char *name_a, *name_b;
3916                 name_a = p->one->path;
3917                 name_b = p->two->path;
3918                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3919                 write_name_quoted(name_a, opt->file, inter_name_termination);
3920                 write_name_quoted(name_b, opt->file, line_termination);
3921         } else {
3922                 const char *name_a, *name_b;
3923                 name_a = p->one->mode ? p->one->path : p->two->path;
3924                 name_b = NULL;
3925                 strip_prefix(opt->prefix_length, &name_a, &name_b);
3926                 write_name_quoted(name_a, opt->file, line_termination);
3927         }
3928 }
3929
3930 int diff_unmodified_pair(struct diff_filepair *p)
3931 {
3932         /* This function is written stricter than necessary to support
3933          * the currently implemented transformers, but the idea is to
3934          * let transformers to produce diff_filepairs any way they want,
3935          * and filter and clean them up here before producing the output.
3936          */
3937         struct diff_filespec *one = p->one, *two = p->two;
3938
3939         if (DIFF_PAIR_UNMERGED(p))
3940                 return 0; /* unmerged is interesting */
3941
3942         /* deletion, addition, mode or type change
3943          * and rename are all interesting.
3944          */
3945         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3946             DIFF_PAIR_MODE_CHANGED(p) ||
3947             strcmp(one->path, two->path))
3948                 return 0;
3949
3950         /* both are valid and point at the same path.  that is, we are
3951          * dealing with a change.
3952          */
3953         if (one->sha1_valid && two->sha1_valid &&
3954             !hashcmp(one->sha1, two->sha1) &&
3955             !one->dirty_submodule && !two->dirty_submodule)
3956                 return 1; /* no change */
3957         if (!one->sha1_valid && !two->sha1_valid)
3958                 return 1; /* both look at the same file on the filesystem. */
3959         return 0;
3960 }
3961
3962 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3963 {
3964         if (diff_unmodified_pair(p))
3965                 return;
3966
3967         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3968             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3969                 return; /* no tree diffs in patch format */
3970
3971         run_diff(p, o);
3972 }
3973
3974 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3975                             struct diffstat_t *diffstat)
3976 {
3977         if (diff_unmodified_pair(p))
3978                 return;
3979
3980         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3981             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3982                 return; /* no useful stat for tree diffs */
3983
3984         run_diffstat(p, o, diffstat);
3985 }
3986
3987 static void diff_flush_checkdiff(struct diff_filepair *p,
3988                 struct diff_options *o)
3989 {
3990         if (diff_unmodified_pair(p))
3991                 return;
3992
3993         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3994             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3995                 return; /* nothing to check in tree diffs */
3996
3997         run_checkdiff(p, o);
3998 }
3999
4000 int diff_queue_is_empty(void)
4001 {
4002         struct diff_queue_struct *q = &diff_queued_diff;
4003         int i;
4004         for (i = 0; i < q->nr; i++)
4005                 if (!diff_unmodified_pair(q->queue[i]))
4006                         return 0;
4007         return 1;
4008 }
4009
4010 #if DIFF_DEBUG
4011 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4012 {
4013         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4014                 x, one ? one : "",
4015                 s->path,
4016                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4017                 s->mode,
4018                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4019         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
4020                 x, one ? one : "",
4021                 s->size, s->xfrm_flags);
4022 }
4023
4024 void diff_debug_filepair(const struct diff_filepair *p, int i)
4025 {
4026         diff_debug_filespec(p->one, i, "one");
4027         diff_debug_filespec(p->two, i, "two");
4028         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4029                 p->score, p->status ? p->status : '?',
4030                 p->one->rename_used, p->broken_pair);
4031 }
4032
4033 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4034 {
4035         int i;
4036         if (msg)
4037                 fprintf(stderr, "%s\n", msg);
4038         fprintf(stderr, "q->nr = %d\n", q->nr);
4039         for (i = 0; i < q->nr; i++) {
4040                 struct diff_filepair *p = q->queue[i];
4041                 diff_debug_filepair(p, i);
4042         }
4043 }
4044 #endif
4045
4046 static void diff_resolve_rename_copy(void)
4047 {
4048         int i;
4049         struct diff_filepair *p;
4050         struct diff_queue_struct *q = &diff_queued_diff;
4051
4052         diff_debug_queue("resolve-rename-copy", q);
4053
4054         for (i = 0; i < q->nr; i++) {
4055                 p = q->queue[i];
4056                 p->status = 0; /* undecided */
4057                 if (DIFF_PAIR_UNMERGED(p))
4058                         p->status = DIFF_STATUS_UNMERGED;
4059                 else if (!DIFF_FILE_VALID(p->one))
4060                         p->status = DIFF_STATUS_ADDED;
4061                 else if (!DIFF_FILE_VALID(p->two))
4062                         p->status = DIFF_STATUS_DELETED;
4063                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4064                         p->status = DIFF_STATUS_TYPE_CHANGED;
4065
4066                 /* from this point on, we are dealing with a pair
4067                  * whose both sides are valid and of the same type, i.e.
4068                  * either in-place edit or rename/copy edit.
4069                  */
4070                 else if (DIFF_PAIR_RENAME(p)) {
4071                         /*
4072                          * A rename might have re-connected a broken
4073                          * pair up, causing the pathnames to be the
4074                          * same again. If so, that's not a rename at
4075                          * all, just a modification..
4076                          *
4077                          * Otherwise, see if this source was used for
4078                          * multiple renames, in which case we decrement
4079                          * the count, and call it a copy.
4080                          */
4081                         if (!strcmp(p->one->path, p->two->path))
4082                                 p->status = DIFF_STATUS_MODIFIED;
4083                         else if (--p->one->rename_used > 0)
4084                                 p->status = DIFF_STATUS_COPIED;
4085                         else
4086                                 p->status = DIFF_STATUS_RENAMED;
4087                 }
4088                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
4089                          p->one->mode != p->two->mode ||
4090                          p->one->dirty_submodule ||
4091                          p->two->dirty_submodule ||
4092                          is_null_sha1(p->one->sha1))
4093                         p->status = DIFF_STATUS_MODIFIED;
4094                 else {
4095                         /* This is a "no-change" entry and should not
4096                          * happen anymore, but prepare for broken callers.
4097                          */
4098                         error("feeding unmodified %s to diffcore",
4099                               p->one->path);
4100                         p->status = DIFF_STATUS_UNKNOWN;
4101                 }
4102         }
4103         diff_debug_queue("resolve-rename-copy done", q);
4104 }
4105
4106 static int check_pair_status(struct diff_filepair *p)
4107 {
4108         switch (p->status) {
4109         case DIFF_STATUS_UNKNOWN:
4110                 return 0;
4111         case 0:
4112                 die("internal error in diff-resolve-rename-copy");
4113         default:
4114                 return 1;
4115         }
4116 }
4117
4118 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4119 {
4120         int fmt = opt->output_format;
4121
4122         if (fmt & DIFF_FORMAT_CHECKDIFF)
4123                 diff_flush_checkdiff(p, opt);
4124         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4125                 diff_flush_raw(p, opt);
4126         else if (fmt & DIFF_FORMAT_NAME) {
4127                 const char *name_a, *name_b;
4128                 name_a = p->two->path;
4129                 name_b = NULL;
4130                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4131                 write_name_quoted(name_a, opt->file, opt->line_termination);
4132         }
4133 }
4134
4135 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4136 {
4137         if (fs->mode)
4138                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4139         else
4140                 fprintf(file, " %s ", newdelete);
4141         write_name_quoted(fs->path, file, '\n');
4142 }
4143
4144
4145 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4146                 const char *line_prefix)
4147 {
4148         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4149                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4150                         p->two->mode, show_name ? ' ' : '\n');
4151                 if (show_name) {
4152                         write_name_quoted(p->two->path, file, '\n');
4153                 }
4154         }
4155 }
4156
4157 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4158                         const char *line_prefix)
4159 {
4160         char *names = pprint_rename(p->one->path, p->two->path);
4161
4162         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4163         free(names);
4164         show_mode_change(file, p, 0, line_prefix);
4165 }
4166
4167 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4168 {
4169         FILE *file = opt->file;
4170         const char *line_prefix = diff_line_prefix(opt);
4171
4172         switch(p->status) {
4173         case DIFF_STATUS_DELETED:
4174                 fputs(line_prefix, file);
4175                 show_file_mode_name(file, "delete", p->one);
4176                 break;
4177         case DIFF_STATUS_ADDED:
4178                 fputs(line_prefix, file);
4179                 show_file_mode_name(file, "create", p->two);
4180                 break;
4181         case DIFF_STATUS_COPIED:
4182                 fputs(line_prefix, file);
4183                 show_rename_copy(file, "copy", p, line_prefix);
4184                 break;
4185         case DIFF_STATUS_RENAMED:
4186                 fputs(line_prefix, file);
4187                 show_rename_copy(file, "rename", p, line_prefix);
4188                 break;
4189         default:
4190                 if (p->score) {
4191                         fprintf(file, "%s rewrite ", line_prefix);
4192                         write_name_quoted(p->two->path, file, ' ');
4193                         fprintf(file, "(%d%%)\n", similarity_index(p));
4194                 }
4195                 show_mode_change(file, p, !p->score, line_prefix);
4196                 break;
4197         }
4198 }
4199
4200 struct patch_id_t {
4201         git_SHA_CTX *ctx;
4202         int patchlen;
4203 };
4204
4205 static int remove_space(char *line, int len)
4206 {
4207         int i;
4208         char *dst = line;
4209         unsigned char c;
4210
4211         for (i = 0; i < len; i++)
4212                 if (!isspace((c = line[i])))
4213                         *dst++ = c;
4214
4215         return dst - line;
4216 }
4217
4218 static void patch_id_consume(void *priv, char *line, unsigned long len)
4219 {
4220         struct patch_id_t *data = priv;
4221         int new_len;
4222
4223         /* Ignore line numbers when computing the SHA1 of the patch */
4224         if (!prefixcmp(line, "@@ -"))
4225                 return;
4226
4227         new_len = remove_space(line, len);
4228
4229         git_SHA1_Update(data->ctx, line, new_len);
4230         data->patchlen += new_len;
4231 }
4232
4233 /* returns 0 upon success, and writes result into sha1 */
4234 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4235 {
4236         struct diff_queue_struct *q = &diff_queued_diff;
4237         int i;
4238         git_SHA_CTX ctx;
4239         struct patch_id_t data;
4240         char buffer[PATH_MAX * 4 + 20];
4241
4242         git_SHA1_Init(&ctx);
4243         memset(&data, 0, sizeof(struct patch_id_t));
4244         data.ctx = &ctx;
4245
4246         for (i = 0; i < q->nr; i++) {
4247                 xpparam_t xpp;
4248                 xdemitconf_t xecfg;
4249                 mmfile_t mf1, mf2;
4250                 struct diff_filepair *p = q->queue[i];
4251                 int len1, len2;
4252
4253                 memset(&xpp, 0, sizeof(xpp));
4254                 memset(&xecfg, 0, sizeof(xecfg));
4255                 if (p->status == 0)
4256                         return error("internal diff status error");
4257                 if (p->status == DIFF_STATUS_UNKNOWN)
4258                         continue;
4259                 if (diff_unmodified_pair(p))
4260                         continue;
4261                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4262                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4263                         continue;
4264                 if (DIFF_PAIR_UNMERGED(p))
4265                         continue;
4266
4267                 diff_fill_sha1_info(p->one);
4268                 diff_fill_sha1_info(p->two);
4269                 if (fill_mmfile(&mf1, p->one) < 0 ||
4270                                 fill_mmfile(&mf2, p->two) < 0)
4271                         return error("unable to read files to diff");
4272
4273                 len1 = remove_space(p->one->path, strlen(p->one->path));
4274                 len2 = remove_space(p->two->path, strlen(p->two->path));
4275                 if (p->one->mode == 0)
4276                         len1 = snprintf(buffer, sizeof(buffer),
4277                                         "diff--gita/%.*sb/%.*s"
4278                                         "newfilemode%06o"
4279                                         "---/dev/null"
4280                                         "+++b/%.*s",
4281                                         len1, p->one->path,
4282                                         len2, p->two->path,
4283                                         p->two->mode,
4284                                         len2, p->two->path);
4285                 else if (p->two->mode == 0)
4286                         len1 = snprintf(buffer, sizeof(buffer),
4287                                         "diff--gita/%.*sb/%.*s"
4288                                         "deletedfilemode%06o"
4289                                         "---a/%.*s"
4290                                         "+++/dev/null",
4291                                         len1, p->one->path,
4292                                         len2, p->two->path,
4293                                         p->one->mode,
4294                                         len1, p->one->path);
4295                 else
4296                         len1 = snprintf(buffer, sizeof(buffer),
4297                                         "diff--gita/%.*sb/%.*s"
4298                                         "---a/%.*s"
4299                                         "+++b/%.*s",
4300                                         len1, p->one->path,
4301                                         len2, p->two->path,
4302                                         len1, p->one->path,
4303                                         len2, p->two->path);
4304                 git_SHA1_Update(&ctx, buffer, len1);
4305
4306                 if (diff_filespec_is_binary(p->one) ||
4307                     diff_filespec_is_binary(p->two)) {
4308                         git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4309                         git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4310                         continue;
4311                 }
4312
4313                 xpp.flags = 0;
4314                 xecfg.ctxlen = 3;
4315                 xecfg.flags = 0;
4316                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4317                               &xpp, &xecfg);
4318         }
4319
4320         git_SHA1_Final(sha1, &ctx);
4321         return 0;
4322 }
4323
4324 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4325 {
4326         struct diff_queue_struct *q = &diff_queued_diff;
4327         int i;
4328         int result = diff_get_patch_id(options, sha1);
4329
4330         for (i = 0; i < q->nr; i++)
4331                 diff_free_filepair(q->queue[i]);
4332
4333         free(q->queue);
4334         DIFF_QUEUE_CLEAR(q);
4335
4336         return result;
4337 }
4338
4339 static int is_summary_empty(const struct diff_queue_struct *q)
4340 {
4341         int i;
4342
4343         for (i = 0; i < q->nr; i++) {
4344                 const struct diff_filepair *p = q->queue[i];
4345
4346                 switch (p->status) {
4347                 case DIFF_STATUS_DELETED:
4348                 case DIFF_STATUS_ADDED:
4349                 case DIFF_STATUS_COPIED:
4350                 case DIFF_STATUS_RENAMED:
4351                         return 0;
4352                 default:
4353                         if (p->score)
4354                                 return 0;
4355                         if (p->one->mode && p->two->mode &&
4356                             p->one->mode != p->two->mode)
4357                                 return 0;
4358                         break;
4359                 }
4360         }
4361         return 1;
4362 }
4363
4364 static const char rename_limit_warning[] =
4365 "inexact rename detection was skipped due to too many files.";
4366
4367 static const char degrade_cc_to_c_warning[] =
4368 "only found copies from modified paths due to too many files.";
4369
4370 static const char rename_limit_advice[] =
4371 "you may want to set your %s variable to at least "
4372 "%d and retry the command.";
4373
4374 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4375 {
4376         if (degraded_cc)
4377                 warning(degrade_cc_to_c_warning);
4378         else if (needed)
4379                 warning(rename_limit_warning);
4380         else
4381                 return;
4382         if (0 < needed && needed < 32767)
4383                 warning(rename_limit_advice, varname, needed);
4384 }
4385
4386 void diff_flush(struct diff_options *options)
4387 {
4388         struct diff_queue_struct *q = &diff_queued_diff;
4389         int i, output_format = options->output_format;
4390         int separator = 0;
4391         int dirstat_by_line = 0;
4392
4393         /*
4394          * Order: raw, stat, summary, patch
4395          * or:    name/name-status/checkdiff (other bits clear)
4396          */
4397         if (!q->nr)
4398                 goto free_queue;
4399
4400         if (output_format & (DIFF_FORMAT_RAW |
4401                              DIFF_FORMAT_NAME |
4402                              DIFF_FORMAT_NAME_STATUS |
4403                              DIFF_FORMAT_CHECKDIFF)) {
4404                 for (i = 0; i < q->nr; i++) {
4405                         struct diff_filepair *p = q->queue[i];
4406                         if (check_pair_status(p))
4407                                 flush_one_pair(p, options);
4408                 }
4409                 separator++;
4410         }
4411
4412         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4413                 dirstat_by_line = 1;
4414
4415         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4416             dirstat_by_line) {
4417                 struct diffstat_t diffstat;
4418
4419                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4420                 for (i = 0; i < q->nr; i++) {
4421                         struct diff_filepair *p = q->queue[i];
4422                         if (check_pair_status(p))
4423                                 diff_flush_stat(p, options, &diffstat);
4424                 }
4425                 if (output_format & DIFF_FORMAT_NUMSTAT)
4426                         show_numstat(&diffstat, options);
4427                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4428                         show_stats(&diffstat, options);
4429                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4430                         show_shortstats(&diffstat, options);
4431                 if (output_format & DIFF_FORMAT_DIRSTAT)
4432                         show_dirstat_by_line(&diffstat, options);
4433                 free_diffstat_info(&diffstat);
4434                 separator++;
4435         }
4436         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4437                 show_dirstat(options);
4438
4439         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4440                 for (i = 0; i < q->nr; i++) {
4441                         diff_summary(options, q->queue[i]);
4442                 }
4443                 separator++;
4444         }
4445
4446         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4447             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4448             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4449                 /*
4450                  * run diff_flush_patch for the exit status. setting
4451                  * options->file to /dev/null should be safe, becaue we
4452                  * aren't supposed to produce any output anyway.
4453                  */
4454                 if (options->close_file)
4455                         fclose(options->file);
4456                 options->file = fopen("/dev/null", "w");
4457                 if (!options->file)
4458                         die_errno("Could not open /dev/null");
4459                 options->close_file = 1;
4460                 for (i = 0; i < q->nr; i++) {
4461                         struct diff_filepair *p = q->queue[i];
4462                         if (check_pair_status(p))
4463                                 diff_flush_patch(p, options);
4464                         if (options->found_changes)
4465                                 break;
4466                 }
4467         }
4468
4469         if (output_format & DIFF_FORMAT_PATCH) {
4470                 if (separator) {
4471                         fprintf(options->file, "%s%c",
4472                                 diff_line_prefix(options),
4473                                 options->line_termination);
4474                         if (options->stat_sep) {
4475                                 /* attach patch instead of inline */
4476                                 fputs(options->stat_sep, options->file);
4477                         }
4478                 }
4479
4480                 for (i = 0; i < q->nr; i++) {
4481                         struct diff_filepair *p = q->queue[i];
4482                         if (check_pair_status(p))
4483                                 diff_flush_patch(p, options);
4484                 }
4485         }
4486
4487         if (output_format & DIFF_FORMAT_CALLBACK)
4488                 options->format_callback(q, options, options->format_callback_data);
4489
4490         for (i = 0; i < q->nr; i++)
4491                 diff_free_filepair(q->queue[i]);
4492 free_queue:
4493         free(q->queue);
4494         DIFF_QUEUE_CLEAR(q);
4495         if (options->close_file)
4496                 fclose(options->file);
4497
4498         /*
4499          * Report the content-level differences with HAS_CHANGES;
4500          * diff_addremove/diff_change does not set the bit when
4501          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4502          */
4503         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4504                 if (options->found_changes)
4505                         DIFF_OPT_SET(options, HAS_CHANGES);
4506                 else
4507                         DIFF_OPT_CLR(options, HAS_CHANGES);
4508         }
4509 }
4510
4511 static void diffcore_apply_filter(const char *filter)
4512 {
4513         int i;
4514         struct diff_queue_struct *q = &diff_queued_diff;
4515         struct diff_queue_struct outq;
4516         DIFF_QUEUE_CLEAR(&outq);
4517
4518         if (!filter)
4519                 return;
4520
4521         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4522                 int found;
4523                 for (i = found = 0; !found && i < q->nr; i++) {
4524                         struct diff_filepair *p = q->queue[i];
4525                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4526                              ((p->score &&
4527                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4528                               (!p->score &&
4529                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4530                             ((p->status != DIFF_STATUS_MODIFIED) &&
4531                              strchr(filter, p->status)))
4532                                 found++;
4533                 }
4534                 if (found)
4535                         return;
4536
4537                 /* otherwise we will clear the whole queue
4538                  * by copying the empty outq at the end of this
4539                  * function, but first clear the current entries
4540                  * in the queue.
4541                  */
4542                 for (i = 0; i < q->nr; i++)
4543                         diff_free_filepair(q->queue[i]);
4544         }
4545         else {
4546                 /* Only the matching ones */
4547                 for (i = 0; i < q->nr; i++) {
4548                         struct diff_filepair *p = q->queue[i];
4549
4550                         if (((p->status == DIFF_STATUS_MODIFIED) &&
4551                              ((p->score &&
4552                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4553                               (!p->score &&
4554                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4555                             ((p->status != DIFF_STATUS_MODIFIED) &&
4556                              strchr(filter, p->status)))
4557                                 diff_q(&outq, p);
4558                         else
4559                                 diff_free_filepair(p);
4560                 }
4561         }
4562         free(q->queue);
4563         *q = outq;
4564 }
4565
4566 /* Check whether two filespecs with the same mode and size are identical */
4567 static int diff_filespec_is_identical(struct diff_filespec *one,
4568                                       struct diff_filespec *two)
4569 {
4570         if (S_ISGITLINK(one->mode))
4571                 return 0;
4572         if (diff_populate_filespec(one, 0))
4573                 return 0;
4574         if (diff_populate_filespec(two, 0))
4575                 return 0;
4576         return !memcmp(one->data, two->data, one->size);
4577 }
4578
4579 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4580 {
4581         int i;
4582         struct diff_queue_struct *q = &diff_queued_diff;
4583         struct diff_queue_struct outq;
4584         DIFF_QUEUE_CLEAR(&outq);
4585
4586         for (i = 0; i < q->nr; i++) {
4587                 struct diff_filepair *p = q->queue[i];
4588
4589                 /*
4590                  * 1. Entries that come from stat info dirtiness
4591                  *    always have both sides (iow, not create/delete),
4592                  *    one side of the object name is unknown, with
4593                  *    the same mode and size.  Keep the ones that
4594                  *    do not match these criteria.  They have real
4595                  *    differences.
4596                  *
4597                  * 2. At this point, the file is known to be modified,
4598                  *    with the same mode and size, and the object
4599                  *    name of one side is unknown.  Need to inspect
4600                  *    the identical contents.
4601                  */
4602                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
4603                     !DIFF_FILE_VALID(p->two) ||
4604                     (p->one->sha1_valid && p->two->sha1_valid) ||
4605                     (p->one->mode != p->two->mode) ||
4606                     diff_populate_filespec(p->one, 1) ||
4607                     diff_populate_filespec(p->two, 1) ||
4608                     (p->one->size != p->two->size) ||
4609                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4610                         diff_q(&outq, p);
4611                 else {
4612                         /*
4613                          * The caller can subtract 1 from skip_stat_unmatch
4614                          * to determine how many paths were dirty only
4615                          * due to stat info mismatch.
4616                          */
4617                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4618                                 diffopt->skip_stat_unmatch++;
4619                         diff_free_filepair(p);
4620                 }
4621         }
4622         free(q->queue);
4623         *q = outq;
4624 }
4625
4626 static int diffnamecmp(const void *a_, const void *b_)
4627 {
4628         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4629         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4630         const char *name_a, *name_b;
4631
4632         name_a = a->one ? a->one->path : a->two->path;
4633         name_b = b->one ? b->one->path : b->two->path;
4634         return strcmp(name_a, name_b);
4635 }
4636
4637 void diffcore_fix_diff_index(struct diff_options *options)
4638 {
4639         struct diff_queue_struct *q = &diff_queued_diff;
4640         qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4641 }
4642
4643 void diffcore_std(struct diff_options *options)
4644 {
4645         if (options->skip_stat_unmatch)
4646                 diffcore_skip_stat_unmatch(options);
4647         if (!options->found_follow) {
4648                 /* See try_to_follow_renames() in tree-diff.c */
4649                 if (options->break_opt != -1)
4650                         diffcore_break(options->break_opt);
4651                 if (options->detect_rename)
4652                         diffcore_rename(options);
4653                 if (options->break_opt != -1)
4654                         diffcore_merge_broken();
4655         }
4656         if (options->pickaxe)
4657                 diffcore_pickaxe(options);
4658         if (options->orderfile)
4659                 diffcore_order(options->orderfile);
4660         if (!options->found_follow)
4661                 /* See try_to_follow_renames() in tree-diff.c */
4662                 diff_resolve_rename_copy();
4663         diffcore_apply_filter(options->filter);
4664
4665         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4666                 DIFF_OPT_SET(options, HAS_CHANGES);
4667         else
4668                 DIFF_OPT_CLR(options, HAS_CHANGES);
4669
4670         options->found_follow = 0;
4671 }
4672
4673 int diff_result_code(struct diff_options *opt, int status)
4674 {
4675         int result = 0;
4676
4677         diff_warn_rename_limit("diff.renameLimit",
4678                                opt->needed_rename_limit,
4679                                opt->degraded_cc_to_c);
4680         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4681             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4682                 return status;
4683         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4684             DIFF_OPT_TST(opt, HAS_CHANGES))
4685                 result |= 01;
4686         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4687             DIFF_OPT_TST(opt, CHECK_FAILED))
4688                 result |= 02;
4689         return result;
4690 }
4691
4692 int diff_can_quit_early(struct diff_options *opt)
4693 {
4694         return (DIFF_OPT_TST(opt, QUICK) &&
4695                 !opt->filter &&
4696                 DIFF_OPT_TST(opt, HAS_CHANGES));
4697 }
4698
4699 /*
4700  * Shall changes to this submodule be ignored?
4701  *
4702  * Submodule changes can be configured to be ignored separately for each path,
4703  * but that configuration can be overridden from the command line.
4704  */
4705 static int is_submodule_ignored(const char *path, struct diff_options *options)
4706 {
4707         int ignored = 0;
4708         unsigned orig_flags = options->flags;
4709         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4710                 set_diffopt_flags_from_submodule_config(options, path);
4711         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4712                 ignored = 1;
4713         options->flags = orig_flags;
4714         return ignored;
4715 }
4716
4717 void diff_addremove(struct diff_options *options,
4718                     int addremove, unsigned mode,
4719                     const unsigned char *sha1,
4720                     int sha1_valid,
4721                     const char *concatpath, unsigned dirty_submodule)
4722 {
4723         struct diff_filespec *one, *two;
4724
4725         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4726                 return;
4727
4728         /* This may look odd, but it is a preparation for
4729          * feeding "there are unchanged files which should
4730          * not produce diffs, but when you are doing copy
4731          * detection you would need them, so here they are"
4732          * entries to the diff-core.  They will be prefixed
4733          * with something like '=' or '*' (I haven't decided
4734          * which but should not make any difference).
4735          * Feeding the same new and old to diff_change()
4736          * also has the same effect.
4737          * Before the final output happens, they are pruned after
4738          * merged into rename/copy pairs as appropriate.
4739          */
4740         if (DIFF_OPT_TST(options, REVERSE_DIFF))
4741                 addremove = (addremove == '+' ? '-' :
4742                              addremove == '-' ? '+' : addremove);
4743
4744         if (options->prefix &&
4745             strncmp(concatpath, options->prefix, options->prefix_length))
4746                 return;
4747
4748         one = alloc_filespec(concatpath);
4749         two = alloc_filespec(concatpath);
4750
4751         if (addremove != '+')
4752                 fill_filespec(one, sha1, sha1_valid, mode);
4753         if (addremove != '-') {
4754                 fill_filespec(two, sha1, sha1_valid, mode);
4755                 two->dirty_submodule = dirty_submodule;
4756         }
4757
4758         diff_queue(&diff_queued_diff, one, two);
4759         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4760                 DIFF_OPT_SET(options, HAS_CHANGES);
4761 }
4762
4763 void diff_change(struct diff_options *options,
4764                  unsigned old_mode, unsigned new_mode,
4765                  const unsigned char *old_sha1,
4766                  const unsigned char *new_sha1,
4767                  int old_sha1_valid, int new_sha1_valid,
4768                  const char *concatpath,
4769                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4770 {
4771         struct diff_filespec *one, *two;
4772
4773         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4774             is_submodule_ignored(concatpath, options))
4775                 return;
4776
4777         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4778                 unsigned tmp;
4779                 const unsigned char *tmp_c;
4780                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4781                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4782                 tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4783                         new_sha1_valid = tmp;
4784                 tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4785                         new_dirty_submodule = tmp;
4786         }
4787
4788         if (options->prefix &&
4789             strncmp(concatpath, options->prefix, options->prefix_length))
4790                 return;
4791
4792         one = alloc_filespec(concatpath);
4793         two = alloc_filespec(concatpath);
4794         fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4795         fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4796         one->dirty_submodule = old_dirty_submodule;
4797         two->dirty_submodule = new_dirty_submodule;
4798
4799         diff_queue(&diff_queued_diff, one, two);
4800         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4801                 DIFF_OPT_SET(options, HAS_CHANGES);
4802 }
4803
4804 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4805 {
4806         struct diff_filepair *pair;
4807         struct diff_filespec *one, *two;
4808
4809         if (options->prefix &&
4810             strncmp(path, options->prefix, options->prefix_length))
4811                 return NULL;
4812
4813         one = alloc_filespec(path);
4814         two = alloc_filespec(path);
4815         pair = diff_queue(&diff_queued_diff, one, two);
4816         pair->is_unmerged = 1;
4817         return pair;
4818 }
4819
4820 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4821                 size_t *outsize)
4822 {
4823         struct diff_tempfile *temp;
4824         const char *argv[3];
4825         const char **arg = argv;
4826         struct child_process child;
4827         struct strbuf buf = STRBUF_INIT;
4828         int err = 0;
4829
4830         temp = prepare_temp_file(spec->path, spec);
4831         *arg++ = pgm;
4832         *arg++ = temp->name;
4833         *arg = NULL;
4834
4835         memset(&child, 0, sizeof(child));
4836         child.use_shell = 1;
4837         child.argv = argv;
4838         child.out = -1;
4839         if (start_command(&child)) {
4840                 remove_tempfile();
4841                 return NULL;
4842         }
4843
4844         if (strbuf_read(&buf, child.out, 0) < 0)
4845                 err = error("error reading from textconv command '%s'", pgm);
4846         close(child.out);
4847
4848         if (finish_command(&child) || err) {
4849                 strbuf_release(&buf);
4850                 remove_tempfile();
4851                 return NULL;
4852         }
4853         remove_tempfile();
4854
4855         return strbuf_detach(&buf, outsize);
4856 }
4857
4858 size_t fill_textconv(struct userdiff_driver *driver,
4859                      struct diff_filespec *df,
4860                      char **outbuf)
4861 {
4862         size_t size;
4863
4864         if (!driver || !driver->textconv) {
4865                 if (!DIFF_FILE_VALID(df)) {
4866                         *outbuf = "";
4867                         return 0;
4868                 }
4869                 if (diff_populate_filespec(df, 0))
4870                         die("unable to read files to diff");
4871                 *outbuf = df->data;
4872                 return df->size;
4873         }
4874
4875         if (driver->textconv_cache && df->sha1_valid) {
4876                 *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4877                                           &size);
4878                 if (*outbuf)
4879                         return size;
4880         }
4881
4882         *outbuf = run_textconv(driver->textconv, df, &size);
4883         if (!*outbuf)
4884                 die("unable to read files to diff");
4885
4886         if (driver->textconv_cache && df->sha1_valid) {
4887                 /* ignore errors, as we might be in a readonly repository */
4888                 notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4889                                 size);
4890                 /*
4891                  * we could save up changes and flush them all at the end,
4892                  * but we would need an extra call after all diffing is done.
4893                  * Since generating a cache entry is the slow path anyway,
4894                  * this extra overhead probably isn't a big deal.
4895                  */
4896                 notes_cache_write(driver->textconv_cache);
4897         }
4898
4899         return size;
4900 }
4901
4902 void setup_diff_pager(struct diff_options *opt)
4903 {
4904         /*
4905          * If the user asked for our exit code, then either they want --quiet
4906          * or --exit-code. We should definitely not bother with a pager in the
4907          * former case, as we will generate no output. Since we still properly
4908          * report our exit code even when a pager is run, we _could_ run a
4909          * pager with --exit-code. But since we have not done so historically,
4910          * and because it is easy to find people oneline advising "git diff
4911          * --exit-code" in hooks and other scripts, we do not do so.
4912          */
4913         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4914             check_pager_config("diff") != 0)
4915                 setup_pager();
4916 }