diff-lib.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "commit.h"
   7 #include "diff.h"
   8 #include "diffcore.h"
   9 #include "revision.h"
  10 #include "cache-tree.h"
  11 #include "path-list.h"
  12
  13 /*
  14  * diff-files
  15  */
  16
  17 static int read_directory(const char *path, struct path_list *list)
  18 {
  19         DIR *dir;
  20         struct dirent *e;
  21
  22         if (!(dir = opendir(path)))
  23                 return error("Could not open directory %s", path);
  24
  25         while ((e = readdir(dir)))
  26                 if (strcmp(".", e->d_name) && strcmp("..", e->d_name))
  27                         path_list_insert(e->d_name, list);
  28
  29         closedir(dir);
  30         return 0;
  31 }
  32
  33 static int get_mode(const char *path, int *mode)
  34 {
  35         struct stat st;
  36
  37         if (!path || is_dev_null(path))
  38                 *mode = 0;
  39         else if (!strcmp(path, "-"))
  40                 *mode = ntohl(create_ce_mode(0666));
  41         else if (stat(path, &st))
  42                 return error("Could not access '%s'", path);
  43         else
  44                 *mode = st.st_mode;
  45         return 0;
  46 }
  47
  48 static int queue_diff(struct diff_options *o,
  49                 const char *name1, const char *name2)
  50 {
  51         int mode1 = 0, mode2 = 0;
  52
  53         if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
  54                 return -1;
  55
  56         if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2))
  57                 return error("file/directory conflict: %s, %s", name1, name2);
  58
  59         if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
  60                 char buffer1[PATH_MAX], buffer2[PATH_MAX];
  61                 struct path_list p1 = {NULL, 0, 0, 1}, p2 = {NULL, 0, 0, 1};
  62                 int len1 = 0, len2 = 0, i1, i2, ret = 0;
  63
  64                 if (name1 && read_directory(name1, &p1))
  65                         return -1;
  66                 if (name2 && read_directory(name2, &p2)) {
  67                         path_list_clear(&p1, 0);
  68                         return -1;
  69                 }
  70
  71                 if (name1) {
  72                         len1 = strlen(name1);
  73                         if (len1 > 0 && name1[len1 - 1] == '/')
  74                                 len1--;
  75                         memcpy(buffer1, name1, len1);
  76                         buffer1[len1++] = '/';
  77                 }
  78
  79                 if (name2) {
  80                         len2 = strlen(name2);
  81                         if (len2 > 0 && name2[len2 - 1] == '/')
  82                                 len2--;
  83                         memcpy(buffer2, name2, len2);
  84                         buffer2[len2++] = '/';
  85                 }
  86
  87                 for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
  88                         const char *n1, *n2;
  89                         int comp;
  90
  91                         if (i1 == p1.nr)
  92                                 comp = 1;
  93                         else if (i2 == p2.nr)
  94                                 comp = -1;
  95                         else
  96                                 comp = strcmp(p1.items[i1].path,
  97                                         p2.items[i2].path);
  98
  99                         if (comp > 0)
 100                                 n1 = NULL;
 101                         else {
 102                                 n1 = buffer1;
 103                                 strncpy(buffer1 + len1, p1.items[i1++].path,
 104                                                 PATH_MAX - len1);
 105                         }
 106
 107                         if (comp < 0)
 108                                 n2 = NULL;
 109                         else {
 110                                 n2 = buffer2;
 111                                 strncpy(buffer2 + len2, p2.items[i2++].path,
 112                                                 PATH_MAX - len2);
 113                         }
 114
 115                         ret = queue_diff(o, n1, n2);
 116                 }
 117                 path_list_clear(&p1, 0);
 118                 path_list_clear(&p2, 0);
 119
 120                 return ret;
 121         } else {
 122                 struct diff_filespec *d1, *d2;
 123
 124                 if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
 125                         unsigned tmp;
 126                         const char *tmp_c;
 127                         tmp = mode1; mode1 = mode2; mode2 = tmp;
 128                         tmp_c = name1; name1 = name2; name2 = tmp_c;
 129                 }
 130
 131                 if (!name1)
 132                         name1 = "/dev/null";
 133                 if (!name2)
 134                         name2 = "/dev/null";
 135                 d1 = alloc_filespec(name1);
 136                 d2 = alloc_filespec(name2);
 137                 fill_filespec(d1, null_sha1, mode1);
 138                 fill_filespec(d2, null_sha1, mode2);
 139
 140                 diff_queue(&diff_queued_diff, d1, d2);
 141                 return 0;
 142         }
 143 }
 144
 145 /*
 146  * Does the path name a blob in the working tree, or a directory
 147  * in the working tree?
 148  */
 149 static int is_in_index(const char *path)
 150 {
 151         int len, pos;
 152         struct cache_entry *ce;
 153
 154         len = strlen(path);
 155         while (path[len-1] == '/')
 156                 len--;
 157         if (!len)
 158                 return 1; /* "." */
 159         pos = cache_name_pos(path, len);
 160         if (0 <= pos)
 161                 return 1;
 162         pos = -1 - pos;
 163         while (pos < active_nr) {
 164                 ce = active_cache[pos++];
 165                 if (ce_namelen(ce) <= len ||
 166                     strncmp(ce->name, path, len) ||
 167                     (ce->name[len] > '/'))
 168                         break; /* path cannot be a prefix */
 169                 if (ce->name[len] == '/')
 170                         return 1;
 171         }
 172         return 0;
 173 }
 174
 175 static int handle_diff_files_args(struct rev_info *revs,
 176                                   int argc, const char **argv,
 177                                   unsigned int *options)
 178 {
 179         *options = 0;
 180
 181         /* revs->max_count == -2 means --no-index */
 182         while (1 < argc && argv[1][0] == '-') {
 183                 if (!strcmp(argv[1], "--base"))
 184                         revs->max_count = 1;
 185                 else if (!strcmp(argv[1], "--ours"))
 186                         revs->max_count = 2;
 187                 else if (!strcmp(argv[1], "--theirs"))
 188                         revs->max_count = 3;
 189                 else if (!strcmp(argv[1], "-n") ||
 190                                 !strcmp(argv[1], "--no-index")) {
 191                         revs->max_count = -2;
 192                         DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
 193                         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
 194                 }
 195                 else if (!strcmp(argv[1], "-q"))
 196                         *options |= DIFF_SILENT_ON_REMOVED;
 197                 else
 198                         return error("invalid option: %s", argv[1]);
 199                 argv++; argc--;
 200         }
 201
 202         if (revs->max_count == -1 && revs->diffopt.nr_paths == 2) {
 203                 /*
 204                  * If two files are specified, and at least one is untracked,
 205                  * default to no-index.
 206                  */
 207                 read_cache();
 208                 if (!is_in_index(revs->diffopt.paths[0]) ||
 209                                         !is_in_index(revs->diffopt.paths[1])) {
 210                         revs->max_count = -2;
 211                         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
 212                 }
 213         }
 214
 215         /*
 216          * Make sure there are NO revision (i.e. pending object) parameter,
 217          * rev.max_count is reasonable (0 <= n <= 3),
 218          * there is no other revision filtering parameters.
 219          */
 220         if (revs->pending.nr || revs->max_count > 3 ||
 221             revs->min_age != -1 || revs->max_age != -1)
 222                 return error("no revision allowed with diff-files");
 223
 224         if (revs->max_count == -1 &&
 225             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
 226                 revs->combine_merges = revs->dense_combined_merges = 1;
 227
 228         return 0;
 229 }
 230
 231 static int is_outside_repo(const char *path, int nongit, const char *prefix)
 232 {
 233         int i;
 234         if (nongit || !strcmp(path, "-") || is_absolute_path(path))
 235                 return 1;
 236 #ifdef __MINGW32__
 237         if (!strcmp(path, "nul"))
 238                 return 1;
 239 #endif
 240         if (prefixcmp(path, "../"))
 241                 return 0;
 242         if (!prefix)
 243                 return 1;
 244         for (i = strlen(prefix); !prefixcmp(path, "../"); ) {
 245                 while (i > 0 && prefix[i - 1] != '/')
 246                         i--;
 247                 if (--i < 0)
 248                         return 1;
 249                 path += 3;
 250         }
 251         return 0;
 252 }
 253
 254 int setup_diff_no_index(struct rev_info *revs,
 255                 int argc, const char ** argv, int nongit, const char *prefix)
 256 {
 257         int i;
 258         for (i = 1; i < argc; i++)
 259                 if (argv[i][0] != '-' || argv[i][1] == '\0')
 260                         break;
 261                 else if (!strcmp(argv[i], "--")) {
 262                         i++;
 263                         break;
 264                 } else if (i < argc - 3 && !strcmp(argv[i], "--no-index")) {
 265                         i = argc - 3;
 266                         DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
 267                         break;
 268                 }
 269         if (argc != i + 2 || (!is_outside_repo(argv[i + 1], nongit, prefix) &&
 270                                 !is_outside_repo(argv[i], nongit, prefix)))
 271                 return -1;
 272
 273         diff_setup(&revs->diffopt);
 274         for (i = 1; i < argc - 2; )
 275                 if (!strcmp(argv[i], "--no-index"))
 276                         i++;
 277                 else {
 278                         int j = diff_opt_parse(&revs->diffopt,
 279                                         argv + i, argc - i);
 280                         if (!j)
 281                                 die("invalid diff option/value: %s", argv[i]);
 282                         i += j;
 283                 }
 284
 285         if (prefix) {
 286                 int len = strlen(prefix);
 287
 288                 revs->diffopt.paths = xcalloc(2, sizeof(char*));
 289                 for (i = 0; i < 2; i++) {
 290                         const char *p = argv[argc - 2 + i];
 291                         /*
 292                          * stdin should be spelled as '-'; if you have
 293                          * path that is '-', spell it as ./-.
 294                          */
 295                         p = (strcmp(p, "-")
 296                              ? xstrdup(prefix_filename(prefix, len, p))
 297                              : p);
 298                         revs->diffopt.paths[i] = p;
 299                 }
 300         }
 301         else
 302                 revs->diffopt.paths = argv + argc - 2;
 303         revs->diffopt.nr_paths = 2;
 304         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
 305         revs->max_count = -2;
 306         if (diff_setup_done(&revs->diffopt) < 0)
 307                 die("diff_setup_done failed");
 308         return 0;
 309 }
 310
 311 int run_diff_files_cmd(struct rev_info *revs, int argc, const char **argv)
 312 {
 313         unsigned int options;
 314
 315         if (handle_diff_files_args(revs, argc, argv, &options))
 316                 return -1;
 317
 318         if (DIFF_OPT_TST(&revs->diffopt, NO_INDEX)) {
 319                 if (revs->diffopt.nr_paths != 2)
 320                         return error("need two files/directories with --no-index");
 321                 if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
 322                                 revs->diffopt.paths[1]))
 323                         return -1;
 324                 diffcore_std(&revs->diffopt);
 325                 diff_flush(&revs->diffopt);
 326                 /*
 327                  * The return code for --no-index imitates diff(1):
 328                  * 0 = no changes, 1 = changes, else error
 329                  */
 330                 return revs->diffopt.found_changes;
 331         }
 332
 333         if (read_cache() < 0) {
 334                 perror("read_cache");
 335                 return -1;
 336         }
 337         return run_diff_files(revs, options);
 338 }
 339
 340 int run_diff_files(struct rev_info *revs, unsigned int option)
 341 {
 342         int entries, i;
 343         int diff_unmerged_stage = revs->max_count;
 344         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
 345         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 346                               ? CE_MATCH_RACY_IS_DIRTY : 0);
 347
 348         if (diff_unmerged_stage < 0)
 349                 diff_unmerged_stage = 2;
 350         entries = active_nr;
 351         for (i = 0; i < entries; i++) {
 352                 struct stat st;
 353                 unsigned int oldmode, newmode;
 354                 struct cache_entry *ce = active_cache[i];
 355                 int changed;
 356
 357                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
 358                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
 359                         break;
 360
 361                 if (!ce_path_match(ce, revs->prune_data))
 362                         continue;
 363
 364                 if (ce_stage(ce)) {
 365                         struct combine_diff_path *dpath;
 366                         int num_compare_stages = 0;
 367                         size_t path_len;
 368
 369                         path_len = ce_namelen(ce);
 370
 371                         dpath = xmalloc(combine_diff_path_size(5, path_len));
 372                         dpath->path = (char *) &(dpath->parent[5]);
 373
 374                         dpath->next = NULL;
 375                         dpath->len = path_len;
 376                         memcpy(dpath->path, ce->name, path_len);
 377                         dpath->path[path_len] = '\0';
 378                         hashclr(dpath->sha1);
 379                         memset(&(dpath->parent[0]), 0,
 380                                sizeof(struct combine_diff_parent)*5);
 381
 382                         if (lstat(ce->name, &st) < 0) {
 383                                 if (errno != ENOENT && errno != ENOTDIR) {
 384                                         perror(ce->name);
 385                                         continue;
 386                                 }
 387                                 if (silent_on_removed)
 388                                         continue;
 389                         }
 390                         else
 391                                 dpath->mode = ntohl(ce_mode_from_stat(ce, st.st_mode));
 392
 393                         while (i < entries) {
 394                                 struct cache_entry *nce = active_cache[i];
 395                                 int stage;
 396
 397                                 if (strcmp(ce->name, nce->name))
 398                                         break;
 399
 400                                 /* Stage #2 (ours) is the first parent,
 401                                  * stage #3 (theirs) is the second.
 402                                  */
 403                                 stage = ce_stage(nce);
 404                                 if (2 <= stage) {
 405                                         int mode = ntohl(nce->ce_mode);
 406                                         num_compare_stages++;
 407                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 408                                         dpath->parent[stage-2].mode = ntohl(ce_mode_from_stat(nce, mode));
 409                                         dpath->parent[stage-2].status =
 410                                                 DIFF_STATUS_MODIFIED;
 411                                 }
 412
 413                                 /* diff against the proper unmerged stage */
 414                                 if (stage == diff_unmerged_stage)
 415                                         ce = nce;
 416                                 i++;
 417                         }
 418                         /*
 419                          * Compensate for loop update
 420                          */
 421                         i--;
 422
 423                         if (revs->combine_merges && num_compare_stages == 2) {
 424                                 show_combined_diff(dpath, 2,
 425                                                    revs->dense_combined_merges,
 426                                                    revs);
 427                                 free(dpath);
 428                                 continue;
 429                         }
 430                         free(dpath);
 431                         dpath = NULL;
 432
 433                         /*
 434                          * Show the diff for the 'ce' if we found the one
 435                          * from the desired stage.
 436                          */
 437                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
 438                         if (ce_stage(ce) != diff_unmerged_stage)
 439                                 continue;
 440                 }
 441
 442                 if (lstat(ce->name, &st) < 0) {
 443                         if (errno != ENOENT && errno != ENOTDIR) {
 444                                 perror(ce->name);
 445                                 continue;
 446                         }
 447                         if (silent_on_removed)
 448                                 continue;
 449                         diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
 450                                        ce->sha1, ce->name, NULL);
 451                         continue;
 452                 }
 453                 changed = ce_match_stat(ce, &st, ce_option);
 454                 if (!changed && !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 455                         continue;
 456                 oldmode = ntohl(ce->ce_mode);
 457                 newmode = ntohl(ce_mode_from_stat(ce, st.st_mode));
 458                 diff_change(&revs->diffopt, oldmode, newmode,
 459                             ce->sha1, (changed ? null_sha1 : ce->sha1),
 460                             ce->name, NULL);
 461
 462         }
 463         diffcore_std(&revs->diffopt);
 464         diff_flush(&revs->diffopt);
 465         return 0;
 466 }
 467
 468 /*
 469  * diff-index
 470  */
 471
 472 /* A file entry went away or appeared */
 473 static void diff_index_show_file(struct rev_info *revs,
 474                                  const char *prefix,
 475                                  struct cache_entry *ce,
 476                                  unsigned char *sha1, unsigned int mode)
 477 {
 478         diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
 479                        sha1, ce->name, NULL);
 480 }
 481
 482 static int get_stat_data(struct cache_entry *ce,
 483                          unsigned char **sha1p,
 484                          unsigned int *modep,
 485                          int cached, int match_missing)
 486 {
 487         unsigned char *sha1 = ce->sha1;
 488         unsigned int mode = ce->ce_mode;
 489
 490         if (!cached) {
 491                 static unsigned char no_sha1[20];
 492                 int changed;
 493                 struct stat st;
 494                 if (lstat(ce->name, &st) < 0) {
 495                         if (errno == ENOENT && match_missing) {
 496                                 *sha1p = sha1;
 497                                 *modep = mode;
 498                                 return 0;
 499                         }
 500                         return -1;
 501                 }
 502                 changed = ce_match_stat(ce, &st, 0);
 503                 if (changed) {
 504                         mode = ce_mode_from_stat(ce, st.st_mode);
 505                         sha1 = no_sha1;
 506                 }
 507         }
 508
 509         *sha1p = sha1;
 510         *modep = mode;
 511         return 0;
 512 }
 513
 514 static void show_new_file(struct rev_info *revs,
 515                           struct cache_entry *new,
 516                           int cached, int match_missing)
 517 {
 518         unsigned char *sha1;
 519         unsigned int mode;
 520
 521         /* New file in the index: it might actually be different in
 522          * the working copy.
 523          */
 524         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
 525                 return;
 526
 527         diff_index_show_file(revs, "+", new, sha1, mode);
 528 }
 529
 530 static int show_modified(struct rev_info *revs,
 531                          struct cache_entry *old,
 532                          struct cache_entry *new,
 533                          int report_missing,
 534                          int cached, int match_missing)
 535 {
 536         unsigned int mode, oldmode;
 537         unsigned char *sha1;
 538
 539         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
 540                 if (report_missing)
 541                         diff_index_show_file(revs, "-", old,
 542                                              old->sha1, old->ce_mode);
 543                 return -1;
 544         }
 545
 546         if (revs->combine_merges && !cached &&
 547             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 548                 struct combine_diff_path *p;
 549                 int pathlen = ce_namelen(new);
 550
 551                 p = xmalloc(combine_diff_path_size(2, pathlen));
 552                 p->path = (char *) &p->parent[2];
 553                 p->next = NULL;
 554                 p->len = pathlen;
 555                 memcpy(p->path, new->name, pathlen);
 556                 p->path[pathlen] = 0;
 557                 p->mode = ntohl(mode);
 558                 hashclr(p->sha1);
 559                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 560                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 561                 p->parent[0].mode = ntohl(new->ce_mode);
 562                 hashcpy(p->parent[0].sha1, new->sha1);
 563                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 564                 p->parent[1].mode = ntohl(old->ce_mode);
 565                 hashcpy(p->parent[1].sha1, old->sha1);
 566                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 567                 free(p);
 568                 return 0;
 569         }
 570
 571         oldmode = old->ce_mode;
 572         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
 573             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 574                 return 0;
 575
 576         mode = ntohl(mode);
 577         oldmode = ntohl(oldmode);
 578
 579         diff_change(&revs->diffopt, oldmode, mode,
 580                     old->sha1, sha1, old->name, NULL);
 581         return 0;
 582 }
 583
 584 static int diff_cache(struct rev_info *revs,
 585                       struct cache_entry **ac, int entries,
 586                       const char **pathspec,
 587                       int cached, int match_missing)
 588 {
 589         while (entries) {
 590                 struct cache_entry *ce = *ac;
 591                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
 592
 593                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
 594                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
 595                         break;
 596
 597                 if (!ce_path_match(ce, pathspec))
 598                         goto skip_entry;
 599
 600                 switch (ce_stage(ce)) {
 601                 case 0:
 602                         /* No stage 1 entry? That means it's a new file */
 603                         if (!same) {
 604                                 show_new_file(revs, ce, cached, match_missing);
 605                                 break;
 606                         }
 607                         /* Show difference between old and new */
 608                         show_modified(revs, ac[1], ce, 1,
 609                                       cached, match_missing);
 610                         break;
 611                 case 1:
 612                         /* No stage 3 (merge) entry?
 613                          * That means it's been deleted.
 614                          */
 615                         if (!same) {
 616                                 diff_index_show_file(revs, "-", ce,
 617                                                      ce->sha1, ce->ce_mode);
 618                                 break;
 619                         }
 620                         /* We come here with ce pointing at stage 1
 621                          * (original tree) and ac[1] pointing at stage
 622                          * 3 (unmerged).  show-modified with
 623                          * report-missing set to false does not say the
 624                          * file is deleted but reports true if work
 625                          * tree does not have it, in which case we
 626                          * fall through to report the unmerged state.
 627                          * Otherwise, we show the differences between
 628                          * the original tree and the work tree.
 629                          */
 630                         if (!cached &&
 631                             !show_modified(revs, ce, ac[1], 0,
 632                                            cached, match_missing))
 633                                 break;
 634                         diff_unmerge(&revs->diffopt, ce->name,
 635                                      ntohl(ce->ce_mode), ce->sha1);
 636                         break;
 637                 case 3:
 638                         diff_unmerge(&revs->diffopt, ce->name,
 639                                      0, null_sha1);
 640                         break;
 641
 642                 default:
 643                         die("impossible cache entry stage");
 644                 }
 645
 646 skip_entry:
 647                 /*
 648                  * Ignore all the different stages for this file,
 649                  * we've handled the relevant cases now.
 650                  */
 651                 do {
 652                         ac++;
 653                         entries--;
 654                 } while (entries && ce_same_name(ce, ac[0]));
 655         }
 656         return 0;
 657 }
 658
 659 /*
 660  * This turns all merge entries into "stage 3". That guarantees that
 661  * when we read in the new tree (into "stage 1"), we won't lose sight
 662  * of the fact that we had unmerged entries.
 663  */
 664 static void mark_merge_entries(void)
 665 {
 666         int i;
 667         for (i = 0; i < active_nr; i++) {
 668                 struct cache_entry *ce = active_cache[i];
 669                 if (!ce_stage(ce))
 670                         continue;
 671                 ce->ce_flags |= htons(CE_STAGEMASK);
 672         }
 673 }
 674
 675 int run_diff_index(struct rev_info *revs, int cached)
 676 {
 677         int ret;
 678         struct object *ent;
 679         struct tree *tree;
 680         const char *tree_name;
 681         int match_missing = 0;
 682
 683         /*
 684          * Backward compatibility wart - "diff-index -m" does
 685          * not mean "do not ignore merges", but totally different.
 686          */
 687         if (!revs->ignore_merges)
 688                 match_missing = 1;
 689
 690         mark_merge_entries();
 691
 692         ent = revs->pending.objects[0].item;
 693         tree_name = revs->pending.objects[0].name;
 694         tree = parse_tree_indirect(ent->sha1);
 695         if (!tree)
 696                 return error("bad tree object %s", tree_name);
 697         if (read_tree(tree, 1, revs->prune_data))
 698                 return error("unable to read tree object %s", tree_name);
 699         ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
 700                          cached, match_missing);
 701         diffcore_std(&revs->diffopt);
 702         diff_flush(&revs->diffopt);
 703         return ret;
 704 }
 705
 706 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 707 {
 708         struct tree *tree;
 709         struct rev_info revs;
 710         int i;
 711         struct cache_entry **dst;
 712         struct cache_entry *last = NULL;
 713
 714         /*
 715          * This is used by git-blame to run diff-cache internally;
 716          * it potentially needs to repeatedly run this, so we will
 717          * start by removing the higher order entries the last round
 718          * left behind.
 719          */
 720         dst = active_cache;
 721         for (i = 0; i < active_nr; i++) {
 722                 struct cache_entry *ce = active_cache[i];
 723                 if (ce_stage(ce)) {
 724                         if (last && !strcmp(ce->name, last->name))
 725                                 continue;
 726                         cache_tree_invalidate_path(active_cache_tree,
 727                                                    ce->name);
 728                         last = ce;
 729                         ce->ce_mode = 0;
 730                         ce->ce_flags &= ~htons(CE_STAGEMASK);
 731                 }
 732                 *dst++ = ce;
 733         }
 734         active_nr = dst - active_cache;
 735
 736         init_revisions(&revs, NULL);
 737         revs.prune_data = opt->paths;
 738         tree = parse_tree_indirect(tree_sha1);
 739         if (!tree)
 740                 die("bad tree object %s", sha1_to_hex(tree_sha1));
 741         if (read_tree(tree, 1, opt->paths))
 742                 return error("unable to read tree %s", sha1_to_hex(tree_sha1));
 743         return diff_cache(&revs, active_cache, active_nr, revs.prune_data,
 744                           1, 0);
 745 }