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 || !strcmp(path, "/dev/null"))
  38                 *mode = 0;
  39         else if (!strcmp(path, "-"))
  40                 *mode = 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         if (prefixcmp(path, "../"))
 237                 return 0;
 238         if (!prefix)
 239                 return 1;
 240         for (i = strlen(prefix); !prefixcmp(path, "../"); ) {
 241                 while (i > 0 && prefix[i - 1] != '/')
 242                         i--;
 243                 if (--i < 0)
 244                         return 1;
 245                 path += 3;
 246         }
 247         return 0;
 248 }
 249
 250 int setup_diff_no_index(struct rev_info *revs,
 251                 int argc, const char ** argv, int nongit, const char *prefix)
 252 {
 253         int i;
 254         for (i = 1; i < argc; i++)
 255                 if (argv[i][0] != '-' || argv[i][1] == '\0')
 256                         break;
 257                 else if (!strcmp(argv[i], "--")) {
 258                         i++;
 259                         break;
 260                 } else if (i < argc - 3 && !strcmp(argv[i], "--no-index")) {
 261                         i = argc - 3;
 262                         DIFF_OPT_SET(&revs->diffopt, EXIT_WITH_STATUS);
 263                         break;
 264                 }
 265         if (argc != i + 2 || (!is_outside_repo(argv[i + 1], nongit, prefix) &&
 266                                 !is_outside_repo(argv[i], nongit, prefix)))
 267                 return -1;
 268
 269         diff_setup(&revs->diffopt);
 270         for (i = 1; i < argc - 2; )
 271                 if (!strcmp(argv[i], "--no-index"))
 272                         i++;
 273                 else {
 274                         int j = diff_opt_parse(&revs->diffopt,
 275                                         argv + i, argc - i);
 276                         if (!j)
 277                                 die("invalid diff option/value: %s", argv[i]);
 278                         i += j;
 279                 }
 280
 281         if (prefix) {
 282                 int len = strlen(prefix);
 283
 284                 revs->diffopt.paths = xcalloc(2, sizeof(char*));
 285                 for (i = 0; i < 2; i++) {
 286                         const char *p = argv[argc - 2 + i];
 287                         /*
 288                          * stdin should be spelled as '-'; if you have
 289                          * path that is '-', spell it as ./-.
 290                          */
 291                         p = (strcmp(p, "-")
 292                              ? xstrdup(prefix_filename(prefix, len, p))
 293                              : p);
 294                         revs->diffopt.paths[i] = p;
 295                 }
 296         }
 297         else
 298                 revs->diffopt.paths = argv + argc - 2;
 299         revs->diffopt.nr_paths = 2;
 300         DIFF_OPT_SET(&revs->diffopt, NO_INDEX);
 301         revs->max_count = -2;
 302         if (diff_setup_done(&revs->diffopt) < 0)
 303                 die("diff_setup_done failed");
 304         return 0;
 305 }
 306
 307 int run_diff_files_cmd(struct rev_info *revs, int argc, const char **argv)
 308 {
 309         unsigned int options;
 310
 311         if (handle_diff_files_args(revs, argc, argv, &options))
 312                 return -1;
 313
 314         if (DIFF_OPT_TST(&revs->diffopt, NO_INDEX)) {
 315                 if (revs->diffopt.nr_paths != 2)
 316                         return error("need two files/directories with --no-index");
 317                 if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
 318                                 revs->diffopt.paths[1]))
 319                         return -1;
 320                 diffcore_std(&revs->diffopt);
 321                 diff_flush(&revs->diffopt);
 322                 /*
 323                  * The return code for --no-index imitates diff(1):
 324                  * 0 = no changes, 1 = changes, else error
 325                  */
 326                 return revs->diffopt.found_changes;
 327         }
 328
 329         if (read_cache() < 0) {
 330                 perror("read_cache");
 331                 return -1;
 332         }
 333         return run_diff_files(revs, options);
 334 }
 335
 336 int run_diff_files(struct rev_info *revs, unsigned int option)
 337 {
 338         int entries, i;
 339         int diff_unmerged_stage = revs->max_count;
 340         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
 341         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 342                               ? CE_MATCH_RACY_IS_DIRTY : 0);
 343
 344         if (diff_unmerged_stage < 0)
 345                 diff_unmerged_stage = 2;
 346         entries = active_nr;
 347         for (i = 0; i < entries; i++) {
 348                 struct stat st;
 349                 unsigned int oldmode, newmode;
 350                 struct cache_entry *ce = active_cache[i];
 351                 int changed;
 352
 353                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
 354                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
 355                         break;
 356
 357                 if (!ce_path_match(ce, revs->prune_data))
 358                         continue;
 359
 360                 if (ce_stage(ce)) {
 361                         struct combine_diff_path *dpath;
 362                         int num_compare_stages = 0;
 363                         size_t path_len;
 364
 365                         path_len = ce_namelen(ce);
 366
 367                         dpath = xmalloc(combine_diff_path_size(5, path_len));
 368                         dpath->path = (char *) &(dpath->parent[5]);
 369
 370                         dpath->next = NULL;
 371                         dpath->len = path_len;
 372                         memcpy(dpath->path, ce->name, path_len);
 373                         dpath->path[path_len] = '\0';
 374                         hashclr(dpath->sha1);
 375                         memset(&(dpath->parent[0]), 0,
 376                                sizeof(struct combine_diff_parent)*5);
 377
 378                         if (lstat(ce->name, &st) < 0) {
 379                                 if (errno != ENOENT && errno != ENOTDIR) {
 380                                         perror(ce->name);
 381                                         continue;
 382                                 }
 383                                 if (silent_on_removed)
 384                                         continue;
 385                         }
 386                         else
 387                                 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
 388
 389                         while (i < entries) {
 390                                 struct cache_entry *nce = active_cache[i];
 391                                 int stage;
 392
 393                                 if (strcmp(ce->name, nce->name))
 394                                         break;
 395
 396                                 /* Stage #2 (ours) is the first parent,
 397                                  * stage #3 (theirs) is the second.
 398                                  */
 399                                 stage = ce_stage(nce);
 400                                 if (2 <= stage) {
 401                                         int mode = nce->ce_mode;
 402                                         num_compare_stages++;
 403                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 404                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 405                                         dpath->parent[stage-2].status =
 406                                                 DIFF_STATUS_MODIFIED;
 407                                 }
 408
 409                                 /* diff against the proper unmerged stage */
 410                                 if (stage == diff_unmerged_stage)
 411                                         ce = nce;
 412                                 i++;
 413                         }
 414                         /*
 415                          * Compensate for loop update
 416                          */
 417                         i--;
 418
 419                         if (revs->combine_merges && num_compare_stages == 2) {
 420                                 show_combined_diff(dpath, 2,
 421                                                    revs->dense_combined_merges,
 422                                                    revs);
 423                                 free(dpath);
 424                                 continue;
 425                         }
 426                         free(dpath);
 427                         dpath = NULL;
 428
 429                         /*
 430                          * Show the diff for the 'ce' if we found the one
 431                          * from the desired stage.
 432                          */
 433                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
 434                         if (ce_stage(ce) != diff_unmerged_stage)
 435                                 continue;
 436                 }
 437
 438                 if (lstat(ce->name, &st) < 0) {
 439                         if (errno != ENOENT && errno != ENOTDIR) {
 440                                 perror(ce->name);
 441                                 continue;
 442                         }
 443                         if (silent_on_removed)
 444                                 continue;
 445                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 446                                        ce->sha1, ce->name, NULL);
 447                         continue;
 448                 }
 449                 changed = ce_match_stat(ce, &st, ce_option);
 450                 if (!changed && !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 451                         continue;
 452                 oldmode = ce->ce_mode;
 453                 newmode = ce_mode_from_stat(ce, st.st_mode);
 454                 diff_change(&revs->diffopt, oldmode, newmode,
 455                             ce->sha1, (changed ? null_sha1 : ce->sha1),
 456                             ce->name, NULL);
 457
 458         }
 459         diffcore_std(&revs->diffopt);
 460         diff_flush(&revs->diffopt);
 461         return 0;
 462 }
 463
 464 /*
 465  * diff-index
 466  */
 467
 468 /* A file entry went away or appeared */
 469 static void diff_index_show_file(struct rev_info *revs,
 470                                  const char *prefix,
 471                                  struct cache_entry *ce,
 472                                  unsigned char *sha1, unsigned int mode)
 473 {
 474         diff_addremove(&revs->diffopt, prefix[0], mode,
 475                        sha1, ce->name, NULL);
 476 }
 477
 478 static int get_stat_data(struct cache_entry *ce,
 479                          unsigned char **sha1p,
 480                          unsigned int *modep,
 481                          int cached, int match_missing)
 482 {
 483         unsigned char *sha1 = ce->sha1;
 484         unsigned int mode = ce->ce_mode;
 485
 486         if (!cached) {
 487                 static unsigned char no_sha1[20];
 488                 int changed;
 489                 struct stat st;
 490                 if (lstat(ce->name, &st) < 0) {
 491                         if (errno == ENOENT && match_missing) {
 492                                 *sha1p = sha1;
 493                                 *modep = mode;
 494                                 return 0;
 495                         }
 496                         return -1;
 497                 }
 498                 changed = ce_match_stat(ce, &st, 0);
 499                 if (changed) {
 500                         mode = ce_mode_from_stat(ce, st.st_mode);
 501                         sha1 = no_sha1;
 502                 }
 503         }
 504
 505         *sha1p = sha1;
 506         *modep = mode;
 507         return 0;
 508 }
 509
 510 static void show_new_file(struct rev_info *revs,
 511                           struct cache_entry *new,
 512                           int cached, int match_missing)
 513 {
 514         unsigned char *sha1;
 515         unsigned int mode;
 516
 517         /* New file in the index: it might actually be different in
 518          * the working copy.
 519          */
 520         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
 521                 return;
 522
 523         diff_index_show_file(revs, "+", new, sha1, mode);
 524 }
 525
 526 static int show_modified(struct rev_info *revs,
 527                          struct cache_entry *old,
 528                          struct cache_entry *new,
 529                          int report_missing,
 530                          int cached, int match_missing)
 531 {
 532         unsigned int mode, oldmode;
 533         unsigned char *sha1;
 534
 535         if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
 536                 if (report_missing)
 537                         diff_index_show_file(revs, "-", old,
 538                                              old->sha1, old->ce_mode);
 539                 return -1;
 540         }
 541
 542         if (revs->combine_merges && !cached &&
 543             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 544                 struct combine_diff_path *p;
 545                 int pathlen = ce_namelen(new);
 546
 547                 p = xmalloc(combine_diff_path_size(2, pathlen));
 548                 p->path = (char *) &p->parent[2];
 549                 p->next = NULL;
 550                 p->len = pathlen;
 551                 memcpy(p->path, new->name, pathlen);
 552                 p->path[pathlen] = 0;
 553                 p->mode = mode;
 554                 hashclr(p->sha1);
 555                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 556                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 557                 p->parent[0].mode = new->ce_mode;
 558                 hashcpy(p->parent[0].sha1, new->sha1);
 559                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 560                 p->parent[1].mode = old->ce_mode;
 561                 hashcpy(p->parent[1].sha1, old->sha1);
 562                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 563                 free(p);
 564                 return 0;
 565         }
 566
 567         oldmode = old->ce_mode;
 568         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
 569             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 570                 return 0;
 571
 572         diff_change(&revs->diffopt, oldmode, mode,
 573                     old->sha1, sha1, old->name, NULL);
 574         return 0;
 575 }
 576
 577 static int diff_cache(struct rev_info *revs,
 578                       struct cache_entry **ac, int entries,
 579                       const char **pathspec,
 580                       int cached, int match_missing)
 581 {
 582         while (entries) {
 583                 struct cache_entry *ce = *ac;
 584                 int same = (entries > 1) && ce_same_name(ce, ac[1]);
 585
 586                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
 587                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
 588                         break;
 589
 590                 if (!ce_path_match(ce, pathspec))
 591                         goto skip_entry;
 592
 593                 switch (ce_stage(ce)) {
 594                 case 0:
 595                         /* No stage 1 entry? That means it's a new file */
 596                         if (!same) {
 597                                 show_new_file(revs, ce, cached, match_missing);
 598                                 break;
 599                         }
 600                         /* Show difference between old and new */
 601                         show_modified(revs, ac[1], ce, 1,
 602                                       cached, match_missing);
 603                         break;
 604                 case 1:
 605                         /* No stage 3 (merge) entry?
 606                          * That means it's been deleted.
 607                          */
 608                         if (!same) {
 609                                 diff_index_show_file(revs, "-", ce,
 610                                                      ce->sha1, ce->ce_mode);
 611                                 break;
 612                         }
 613                         /* We come here with ce pointing at stage 1
 614                          * (original tree) and ac[1] pointing at stage
 615                          * 3 (unmerged).  show-modified with
 616                          * report-missing set to false does not say the
 617                          * file is deleted but reports true if work
 618                          * tree does not have it, in which case we
 619                          * fall through to report the unmerged state.
 620                          * Otherwise, we show the differences between
 621                          * the original tree and the work tree.
 622                          */
 623                         if (!cached &&
 624                             !show_modified(revs, ce, ac[1], 0,
 625                                            cached, match_missing))
 626                                 break;
 627                         diff_unmerge(&revs->diffopt, ce->name,
 628                                      ce->ce_mode, ce->sha1);
 629                         break;
 630                 case 3:
 631                         diff_unmerge(&revs->diffopt, ce->name,
 632                                      0, null_sha1);
 633                         break;
 634
 635                 default:
 636                         die("impossible cache entry stage");
 637                 }
 638
 639 skip_entry:
 640                 /*
 641                  * Ignore all the different stages for this file,
 642                  * we've handled the relevant cases now.
 643                  */
 644                 do {
 645                         ac++;
 646                         entries--;
 647                 } while (entries && ce_same_name(ce, ac[0]));
 648         }
 649         return 0;
 650 }
 651
 652 /*
 653  * This turns all merge entries into "stage 3". That guarantees that
 654  * when we read in the new tree (into "stage 1"), we won't lose sight
 655  * of the fact that we had unmerged entries.
 656  */
 657 static void mark_merge_entries(void)
 658 {
 659         int i;
 660         for (i = 0; i < active_nr; i++) {
 661                 struct cache_entry *ce = active_cache[i];
 662                 if (!ce_stage(ce))
 663                         continue;
 664                 ce->ce_flags |= CE_STAGEMASK;
 665         }
 666 }
 667
 668 int run_diff_index(struct rev_info *revs, int cached)
 669 {
 670         int ret;
 671         struct object *ent;
 672         struct tree *tree;
 673         const char *tree_name;
 674         int match_missing = 0;
 675
 676         /*
 677          * Backward compatibility wart - "diff-index -m" does
 678          * not mean "do not ignore merges", but totally different.
 679          */
 680         if (!revs->ignore_merges)
 681                 match_missing = 1;
 682
 683         mark_merge_entries();
 684
 685         ent = revs->pending.objects[0].item;
 686         tree_name = revs->pending.objects[0].name;
 687         tree = parse_tree_indirect(ent->sha1);
 688         if (!tree)
 689                 return error("bad tree object %s", tree_name);
 690         if (read_tree(tree, 1, revs->prune_data))
 691                 return error("unable to read tree object %s", tree_name);
 692         ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
 693                          cached, match_missing);
 694         diffcore_std(&revs->diffopt);
 695         diff_flush(&revs->diffopt);
 696         return ret;
 697 }
 698
 699 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 700 {
 701         struct tree *tree;
 702         struct rev_info revs;
 703         int i;
 704         struct cache_entry **dst;
 705         struct cache_entry *last = NULL;
 706
 707         /*
 708          * This is used by git-blame to run diff-cache internally;
 709          * it potentially needs to repeatedly run this, so we will
 710          * start by removing the higher order entries the last round
 711          * left behind.
 712          */
 713         dst = active_cache;
 714         for (i = 0; i < active_nr; i++) {
 715                 struct cache_entry *ce = active_cache[i];
 716                 if (ce_stage(ce)) {
 717                         if (last && !strcmp(ce->name, last->name))
 718                                 continue;
 719                         cache_tree_invalidate_path(active_cache_tree,
 720                                                    ce->name);
 721                         last = ce;
 722                         ce->ce_flags |= CE_REMOVE;
 723                 }
 724                 *dst++ = ce;
 725         }
 726         active_nr = dst - active_cache;
 727
 728         init_revisions(&revs, NULL);
 729         revs.prune_data = opt->paths;
 730         tree = parse_tree_indirect(tree_sha1);
 731         if (!tree)
 732                 die("bad tree object %s", sha1_to_hex(tree_sha1));
 733         if (read_tree(tree, 1, opt->paths))
 734                 return error("unable to read tree %s", sha1_to_hex(tree_sha1));
 735         return diff_cache(&revs, active_cache, active_nr, revs.prune_data,
 736                           1, 0);
 737 }