diff-lib.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "git-compat-util.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "gettext.h"
   9 #include "hash.h"
  10 #include "hex.h"
  11 #include "object-name.h"
  12 #include "read-cache.h"
  13 #include "revision.h"
  14 #include "cache-tree.h"
  15 #include "unpack-trees.h"
  16 #include "refs.h"
  17 #include "repository.h"
  18 #include "submodule.h"
  19 #include "symlinks.h"
  20 #include "trace.h"
  21 #include "dir.h"
  22 #include "fsmonitor.h"
  23 #include "commit-reach.h"
  24
  25 /*
  26  * diff-files
  27  */
  28
  29 /*
  30  * Has the work tree entity been removed?
  31  *
  32  * Return 1 if it was removed from the work tree, 0 if an entity to be
  33  * compared with the cache entry ce still exists (the latter includes
  34  * the case where a directory that is not a submodule repository
  35  * exists for ce that is a submodule -- it is a submodule that is not
  36  * checked out).  Return negative for an error.
  37  */
  38 static int check_removed(const struct cache_entry *ce, struct stat *st)
  39 {
  40         int stat_err;
  41
  42         if (!(ce->ce_flags & CE_FSMONITOR_VALID))
  43                 stat_err = lstat(ce->name, st);
  44         else
  45                 stat_err = fake_lstat(ce, st);
  46         if (stat_err < 0) {
  47                 if (!is_missing_file_error(errno))
  48                         return -1;
  49                 return 1;
  50         }
  51
  52         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
  53                 return 1;
  54         if (S_ISDIR(st->st_mode)) {
  55                 struct object_id sub;
  56
  57                 /*
  58                  * If ce is already a gitlink, we can have a plain
  59                  * directory (i.e. the submodule is not checked out),
  60                  * or a checked out submodule.  Either case this is not
  61                  * a case where something was removed from the work tree,
  62                  * so we will return 0.
  63                  *
  64                  * Otherwise, if the directory is not a submodule
  65                  * repository, that means ce which was a blob turned into
  66                  * a directory --- the blob was removed!
  67                  */
  68                 if (!S_ISGITLINK(ce->ce_mode) &&
  69                     resolve_gitlink_ref(ce->name, "HEAD", &sub))
  70                         return 1;
  71         }
  72         return 0;
  73 }
  74
  75 /*
  76  * Has a file changed or has a submodule new commits or a dirty work tree?
  77  *
  78  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
  79  * option is set, the caller does not only want to know if a submodule is
  80  * modified at all but wants to know all the conditions that are met (new
  81  * commits, untracked content and/or modified content).
  82  */
  83 static int match_stat_with_submodule(struct diff_options *diffopt,
  84                                      const struct cache_entry *ce,
  85                                      struct stat *st, unsigned ce_option,
  86                                      unsigned *dirty_submodule)
  87 {
  88         int changed = ie_match_stat(diffopt->repo->index, ce, st, ce_option);
  89         if (S_ISGITLINK(ce->ce_mode)) {
  90                 struct diff_flags orig_flags = diffopt->flags;
  91                 if (!diffopt->flags.override_submodule_config)
  92                         set_diffopt_flags_from_submodule_config(diffopt, ce->name);
  93                 if (diffopt->flags.ignore_submodules)
  94                         changed = 0;
  95                 else if (!diffopt->flags.ignore_dirty_submodules &&
  96                          (!changed || diffopt->flags.dirty_submodules))
  97                         *dirty_submodule = is_submodule_modified(ce->name,
  98                                                                  diffopt->flags.ignore_untracked_in_submodules);
  99                 diffopt->flags = orig_flags;
 100         }
 101         return changed;
 102 }
 103
 104 void run_diff_files(struct rev_info *revs, unsigned int option)
 105 {
 106         int entries, i;
 107         int diff_unmerged_stage = revs->max_count;
 108         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 109                               ? CE_MATCH_RACY_IS_DIRTY : 0);
 110         uint64_t start = getnanotime();
 111         struct index_state *istate = revs->diffopt.repo->index;
 112
 113         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
 114
 115         refresh_fsmonitor(istate);
 116
 117         if (diff_unmerged_stage < 0)
 118                 diff_unmerged_stage = 2;
 119         entries = istate->cache_nr;
 120         for (i = 0; i < entries; i++) {
 121                 unsigned int oldmode, newmode;
 122                 struct cache_entry *ce = istate->cache[i];
 123                 int changed;
 124                 unsigned dirty_submodule = 0;
 125                 const struct object_id *old_oid, *new_oid;
 126
 127                 if (diff_can_quit_early(&revs->diffopt))
 128                         break;
 129
 130                 if (!ce_path_match(istate, ce, &revs->prune_data, NULL))
 131                         continue;
 132
 133                 if (revs->diffopt.prefix &&
 134                     strncmp(ce->name, revs->diffopt.prefix, revs->diffopt.prefix_length))
 135                         continue;
 136
 137                 if (ce_stage(ce)) {
 138                         struct combine_diff_path *dpath;
 139                         struct diff_filepair *pair;
 140                         unsigned int wt_mode = 0;
 141                         int num_compare_stages = 0;
 142                         size_t path_len;
 143                         struct stat st;
 144
 145                         path_len = ce_namelen(ce);
 146
 147                         dpath = xmalloc(combine_diff_path_size(5, path_len));
 148                         dpath->path = (char *) &(dpath->parent[5]);
 149
 150                         dpath->next = NULL;
 151                         memcpy(dpath->path, ce->name, path_len);
 152                         dpath->path[path_len] = '\0';
 153                         oidclr(&dpath->oid);
 154                         memset(&(dpath->parent[0]), 0,
 155                                sizeof(struct combine_diff_parent)*5);
 156
 157                         changed = check_removed(ce, &st);
 158                         if (!changed)
 159                                 wt_mode = ce_mode_from_stat(ce, st.st_mode);
 160                         else {
 161                                 if (changed < 0) {
 162                                         perror(ce->name);
 163                                         continue;
 164                                 }
 165                                 wt_mode = 0;
 166                         }
 167                         dpath->mode = wt_mode;
 168
 169                         while (i < entries) {
 170                                 struct cache_entry *nce = istate->cache[i];
 171                                 int stage;
 172
 173                                 if (strcmp(ce->name, nce->name))
 174                                         break;
 175
 176                                 /* Stage #2 (ours) is the first parent,
 177                                  * stage #3 (theirs) is the second.
 178                                  */
 179                                 stage = ce_stage(nce);
 180                                 if (2 <= stage) {
 181                                         int mode = nce->ce_mode;
 182                                         num_compare_stages++;
 183                                         oidcpy(&dpath->parent[stage - 2].oid,
 184                                                &nce->oid);
 185                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 186                                         dpath->parent[stage-2].status =
 187                                                 DIFF_STATUS_MODIFIED;
 188                                 }
 189
 190                                 /* diff against the proper unmerged stage */
 191                                 if (stage == diff_unmerged_stage)
 192                                         ce = nce;
 193                                 i++;
 194                         }
 195                         /*
 196                          * Compensate for loop update
 197                          */
 198                         i--;
 199
 200                         if (revs->combine_merges && num_compare_stages == 2) {
 201                                 show_combined_diff(dpath, 2, revs);
 202                                 free(dpath);
 203                                 continue;
 204                         }
 205                         FREE_AND_NULL(dpath);
 206
 207                         /*
 208                          * Show the diff for the 'ce' if we found the one
 209                          * from the desired stage.
 210                          */
 211                         pair = diff_unmerge(&revs->diffopt, ce->name);
 212                         if (wt_mode)
 213                                 pair->two->mode = wt_mode;
 214                         if (ce_stage(ce) != diff_unmerged_stage)
 215                                 continue;
 216                 }
 217
 218                 if (ce_uptodate(ce) || ce_skip_worktree(ce))
 219                         continue;
 220
 221                 /*
 222                  * When CE_VALID is set (via "update-index --assume-unchanged"
 223                  * or via adding paths while core.ignorestat is set to true),
 224                  * the user has promised that the working tree file for that
 225                  * path will not be modified.  When CE_FSMONITOR_VALID is true,
 226                  * the fsmonitor knows that the path hasn't been modified since
 227                  * we refreshed the cached stat information.  In either case,
 228                  * we do not have to stat to see if the path has been removed
 229                  * or modified.
 230                  */
 231                 if (ce->ce_flags & (CE_VALID | CE_FSMONITOR_VALID)) {
 232                         changed = 0;
 233                         newmode = ce->ce_mode;
 234                 } else {
 235                         struct stat st;
 236
 237                         changed = check_removed(ce, &st);
 238                         if (changed) {
 239                                 if (changed < 0) {
 240                                         perror(ce->name);
 241                                         continue;
 242                                 }
 243                                 diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 244                                                &ce->oid,
 245                                                !is_null_oid(&ce->oid),
 246                                                ce->name, 0);
 247                                 continue;
 248                         } else if (revs->diffopt.ita_invisible_in_index &&
 249                                    ce_intent_to_add(ce)) {
 250                                 newmode = ce_mode_from_stat(ce, st.st_mode);
 251                                 diff_addremove(&revs->diffopt, '+', newmode,
 252                                                null_oid(), 0, ce->name, 0);
 253                                 continue;
 254                         }
 255
 256                         changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
 257                                                             ce_option, &dirty_submodule);
 258                         newmode = ce_mode_from_stat(ce, st.st_mode);
 259                 }
 260
 261                 if (!changed && !dirty_submodule) {
 262                         ce_mark_uptodate(ce);
 263                         mark_fsmonitor_valid(istate, ce);
 264                         if (!revs->diffopt.flags.find_copies_harder)
 265                                 continue;
 266                 }
 267                 oldmode = ce->ce_mode;
 268                 old_oid = &ce->oid;
 269                 new_oid = changed ? null_oid() : &ce->oid;
 270                 diff_change(&revs->diffopt, oldmode, newmode,
 271                             old_oid, new_oid,
 272                             !is_null_oid(old_oid),
 273                             !is_null_oid(new_oid),
 274                             ce->name, 0, dirty_submodule);
 275
 276         }
 277         diffcore_std(&revs->diffopt);
 278         diff_flush(&revs->diffopt);
 279         trace_performance_since(start, "diff-files");
 280 }
 281
 282 /*
 283  * diff-index
 284  */
 285
 286 /* A file entry went away or appeared */
 287 static void diff_index_show_file(struct rev_info *revs,
 288                                  const char *prefix,
 289                                  const struct cache_entry *ce,
 290                                  const struct object_id *oid, int oid_valid,
 291                                  unsigned int mode,
 292                                  unsigned dirty_submodule)
 293 {
 294         diff_addremove(&revs->diffopt, prefix[0], mode,
 295                        oid, oid_valid, ce->name, dirty_submodule);
 296 }
 297
 298 static int get_stat_data(const struct index_state *istate,
 299                          const struct cache_entry *ce,
 300                          const struct object_id **oidp,
 301                          unsigned int *modep,
 302                          int cached, int match_missing,
 303                          unsigned *dirty_submodule, struct diff_options *diffopt)
 304 {
 305         const struct object_id *oid = &ce->oid;
 306         unsigned int mode = ce->ce_mode;
 307
 308         if (!cached && !ce_uptodate(ce)) {
 309                 int changed;
 310                 struct stat st;
 311                 changed = check_removed(ce, &st);
 312                 if (changed < 0)
 313                         return -1;
 314                 else if (changed) {
 315                         if (match_missing) {
 316                                 *oidp = oid;
 317                                 *modep = mode;
 318                                 return 0;
 319                         }
 320                         return -1;
 321                 }
 322                 changed = match_stat_with_submodule(diffopt, ce, &st,
 323                                                     0, dirty_submodule);
 324                 if (changed) {
 325                         mode = ce_mode_from_stat(ce, st.st_mode);
 326                         oid = null_oid();
 327                 }
 328         }
 329
 330         *oidp = oid;
 331         *modep = mode;
 332         return 0;
 333 }
 334
 335 static void show_new_file(struct rev_info *revs,
 336                           const struct cache_entry *new_file,
 337                           int cached, int match_missing)
 338 {
 339         const struct object_id *oid;
 340         unsigned int mode;
 341         unsigned dirty_submodule = 0;
 342         struct index_state *istate = revs->diffopt.repo->index;
 343
 344         if (new_file && S_ISSPARSEDIR(new_file->ce_mode)) {
 345                 diff_tree_oid(NULL, &new_file->oid, new_file->name, &revs->diffopt);
 346                 return;
 347         }
 348
 349         /*
 350          * New file in the index: it might actually be different in
 351          * the working tree.
 352          */
 353         if (get_stat_data(istate, new_file, &oid, &mode, cached, match_missing,
 354             &dirty_submodule, &revs->diffopt) < 0)
 355                 return;
 356
 357         diff_index_show_file(revs, "+", new_file, oid, !is_null_oid(oid), mode, dirty_submodule);
 358 }
 359
 360 static int show_modified(struct rev_info *revs,
 361                          const struct cache_entry *old_entry,
 362                          const struct cache_entry *new_entry,
 363                          int report_missing,
 364                          int cached, int match_missing)
 365 {
 366         unsigned int mode, oldmode;
 367         const struct object_id *oid;
 368         unsigned dirty_submodule = 0;
 369         struct index_state *istate = revs->diffopt.repo->index;
 370
 371         assert(S_ISSPARSEDIR(old_entry->ce_mode) ==
 372                S_ISSPARSEDIR(new_entry->ce_mode));
 373
 374         /*
 375          * If both are sparse directory entries, then expand the
 376          * modifications to the file level. If only one was a sparse
 377          * directory, then they appear as an add and delete instead of
 378          * a modification.
 379          */
 380         if (S_ISSPARSEDIR(new_entry->ce_mode)) {
 381                 diff_tree_oid(&old_entry->oid, &new_entry->oid, new_entry->name, &revs->diffopt);
 382                 return 0;
 383         }
 384
 385         if (get_stat_data(istate, new_entry, &oid, &mode, cached, match_missing,
 386                           &dirty_submodule, &revs->diffopt) < 0) {
 387                 if (report_missing)
 388                         diff_index_show_file(revs, "-", old_entry,
 389                                              &old_entry->oid, 1, old_entry->ce_mode,
 390                                              0);
 391                 return -1;
 392         }
 393
 394         if (revs->combine_merges && !cached &&
 395             (!oideq(oid, &old_entry->oid) || !oideq(&old_entry->oid, &new_entry->oid))) {
 396                 struct combine_diff_path *p;
 397                 int pathlen = ce_namelen(new_entry);
 398
 399                 p = xmalloc(combine_diff_path_size(2, pathlen));
 400                 p->path = (char *) &p->parent[2];
 401                 p->next = NULL;
 402                 memcpy(p->path, new_entry->name, pathlen);
 403                 p->path[pathlen] = 0;
 404                 p->mode = mode;
 405                 oidclr(&p->oid);
 406                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 407                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 408                 p->parent[0].mode = new_entry->ce_mode;
 409                 oidcpy(&p->parent[0].oid, &new_entry->oid);
 410                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 411                 p->parent[1].mode = old_entry->ce_mode;
 412                 oidcpy(&p->parent[1].oid, &old_entry->oid);
 413                 show_combined_diff(p, 2, revs);
 414                 free(p);
 415                 return 0;
 416         }
 417
 418         oldmode = old_entry->ce_mode;
 419         if (mode == oldmode && oideq(oid, &old_entry->oid) && !dirty_submodule &&
 420             !revs->diffopt.flags.find_copies_harder)
 421                 return 0;
 422
 423         diff_change(&revs->diffopt, oldmode, mode,
 424                     &old_entry->oid, oid, 1, !is_null_oid(oid),
 425                     old_entry->name, 0, dirty_submodule);
 426         return 0;
 427 }
 428
 429 /*
 430  * This gets a mix of an existing index and a tree, one pathname entry
 431  * at a time. The index entry may be a single stage-0 one, but it could
 432  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 433  * give you the position and number of entries in the index).
 434  */
 435 static void do_oneway_diff(struct unpack_trees_options *o,
 436                            const struct cache_entry *idx,
 437                            const struct cache_entry *tree)
 438 {
 439         struct rev_info *revs = o->unpack_data;
 440         int match_missing, cached;
 441
 442         /*
 443          * i-t-a entries do not actually exist in the index (if we're
 444          * looking at its content)
 445          */
 446         if (o->index_only &&
 447             revs->diffopt.ita_invisible_in_index &&
 448             idx && ce_intent_to_add(idx)) {
 449                 idx = NULL;
 450                 if (!tree)
 451                         return; /* nothing to diff.. */
 452         }
 453
 454         /* if the entry is not checked out, don't examine work tree */
 455         cached = o->index_only ||
 456                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
 457
 458         match_missing = revs->match_missing;
 459
 460         if (cached && idx && ce_stage(idx)) {
 461                 struct diff_filepair *pair;
 462                 pair = diff_unmerge(&revs->diffopt, idx->name);
 463                 if (tree)
 464                         fill_filespec(pair->one, &tree->oid, 1,
 465                                       tree->ce_mode);
 466                 return;
 467         }
 468
 469         /*
 470          * Something added to the tree?
 471          */
 472         if (!tree) {
 473                 show_new_file(revs, idx, cached, match_missing);
 474                 return;
 475         }
 476
 477         /*
 478          * Something removed from the tree?
 479          */
 480         if (!idx) {
 481                 if (S_ISSPARSEDIR(tree->ce_mode)) {
 482                         diff_tree_oid(&tree->oid, NULL, tree->name, &revs->diffopt);
 483                         return;
 484                 }
 485
 486                 diff_index_show_file(revs, "-", tree, &tree->oid, 1,
 487                                      tree->ce_mode, 0);
 488                 return;
 489         }
 490
 491         /* Show difference between old and new */
 492         show_modified(revs, tree, idx, 1, cached, match_missing);
 493 }
 494
 495 /*
 496  * The unpack_trees() interface is designed for merging, so
 497  * the different source entries are designed primarily for
 498  * the source trees, with the old index being really mainly
 499  * used for being replaced by the result.
 500  *
 501  * For diffing, the index is more important, and we only have a
 502  * single tree.
 503  *
 504  * We're supposed to advance o->pos to skip what we have already processed.
 505  *
 506  * This wrapper makes it all more readable, and takes care of all
 507  * the fairly complex unpack_trees() semantic requirements, including
 508  * the skipping, the path matching, the type conflict cases etc.
 509  */
 510 static int oneway_diff(const struct cache_entry * const *src,
 511                        struct unpack_trees_options *o)
 512 {
 513         const struct cache_entry *idx = src[0];
 514         const struct cache_entry *tree = src[1];
 515         struct rev_info *revs = o->unpack_data;
 516
 517         /*
 518          * Unpack-trees generates a DF/conflict entry if
 519          * there was a directory in the index and a tree
 520          * in the tree. From a diff standpoint, that's a
 521          * delete of the tree and a create of the file.
 522          */
 523         if (tree == o->df_conflict_entry)
 524                 tree = NULL;
 525
 526         if (ce_path_match(revs->diffopt.repo->index,
 527                           idx ? idx : tree,
 528                           &revs->prune_data, NULL)) {
 529                 do_oneway_diff(o, idx, tree);
 530                 if (diff_can_quit_early(&revs->diffopt)) {
 531                         o->exiting_early = 1;
 532                         return -1;
 533                 }
 534         }
 535
 536         return 0;
 537 }
 538
 539 static int diff_cache(struct rev_info *revs,
 540                       const struct object_id *tree_oid,
 541                       const char *tree_name,
 542                       int cached)
 543 {
 544         struct tree *tree;
 545         struct tree_desc t;
 546         struct unpack_trees_options opts;
 547
 548         tree = parse_tree_indirect(tree_oid);
 549         if (!tree)
 550                 return error("bad tree object %s",
 551                              tree_name ? tree_name : oid_to_hex(tree_oid));
 552         memset(&opts, 0, sizeof(opts));
 553         opts.head_idx = 1;
 554         opts.index_only = cached;
 555         opts.diff_index_cached = (cached &&
 556                                   !revs->diffopt.flags.find_copies_harder);
 557         opts.merge = 1;
 558         opts.fn = oneway_diff;
 559         opts.unpack_data = revs;
 560         opts.src_index = revs->diffopt.repo->index;
 561         opts.dst_index = NULL;
 562         opts.pathspec = &revs->diffopt.pathspec;
 563         opts.pathspec->recursive = 1;
 564
 565         init_tree_desc(&t, &tree->object.oid, tree->buffer, tree->size);
 566         return unpack_trees(1, &t, &opts);
 567 }
 568
 569 void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
 570 {
 571         int i;
 572         struct commit *mb_child[2] = {0};
 573         struct commit_list *merge_bases = NULL;
 574
 575         for (i = 0; i < revs->pending.nr; i++) {
 576                 struct object *obj = revs->pending.objects[i].item;
 577                 if (obj->flags)
 578                         die(_("--merge-base does not work with ranges"));
 579         }
 580
 581         /*
 582          * This check must go after the for loop above because A...B
 583          * ranges produce three pending commits, resulting in a
 584          * misleading error message.
 585          */
 586         if (revs->pending.nr < 1 || revs->pending.nr > 2)
 587                 BUG("unexpected revs->pending.nr: %d", revs->pending.nr);
 588
 589         for (i = 0; i < revs->pending.nr; i++)
 590                 mb_child[i] = lookup_commit_reference(the_repository, &revs->pending.objects[i].item->oid);
 591         if (revs->pending.nr == 1) {
 592                 struct object_id oid;
 593
 594                 if (repo_get_oid(the_repository, "HEAD", &oid))
 595                         die(_("unable to get HEAD"));
 596
 597                 mb_child[1] = lookup_commit_reference(the_repository, &oid);
 598         }
 599
 600         if (repo_get_merge_bases(the_repository, mb_child[0], mb_child[1], &merge_bases) < 0)
 601                 exit(128);
 602         if (!merge_bases)
 603                 die(_("no merge base found"));
 604         if (merge_bases->next)
 605                 die(_("multiple merge bases found"));
 606
 607         oidcpy(mb, &merge_bases->item->object.oid);
 608
 609         free_commit_list(merge_bases);
 610 }
 611
 612 void run_diff_index(struct rev_info *revs, unsigned int option)
 613 {
 614         struct object_array_entry *ent;
 615         int cached = !!(option & DIFF_INDEX_CACHED);
 616         int merge_base = !!(option & DIFF_INDEX_MERGE_BASE);
 617         struct object_id oid;
 618         const char *name;
 619         char merge_base_hex[GIT_MAX_HEXSZ + 1];
 620         struct index_state *istate = revs->diffopt.repo->index;
 621
 622         if (revs->pending.nr != 1)
 623                 BUG("run_diff_index must be passed exactly one tree");
 624
 625         trace_performance_enter();
 626         ent = revs->pending.objects;
 627
 628         refresh_fsmonitor(istate);
 629
 630         if (merge_base) {
 631                 diff_get_merge_base(revs, &oid);
 632                 name = oid_to_hex_r(merge_base_hex, &oid);
 633         } else {
 634                 oidcpy(&oid, &ent->item->oid);
 635                 name = ent->name;
 636         }
 637
 638         if (diff_cache(revs, &oid, name, cached))
 639                 exit(128);
 640
 641         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 642         diffcore_fix_diff_index();
 643         diffcore_std(&revs->diffopt);
 644         diff_flush(&revs->diffopt);
 645         trace_performance_leave("diff-index");
 646 }
 647
 648 int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)
 649 {
 650         struct rev_info revs;
 651
 652         repo_init_revisions(opt->repo, &revs, NULL);
 653         copy_pathspec(&revs.prune_data, &opt->pathspec);
 654         diff_setup_done(&revs.diffopt);
 655         revs.diffopt = *opt;
 656
 657         if (diff_cache(&revs, tree_oid, NULL, 1))
 658                 exit(128);
 659         release_revisions(&revs);
 660         return 0;
 661 }
 662
 663 int index_differs_from(struct repository *r,
 664                        const char *def, const struct diff_flags *flags,
 665                        int ita_invisible_in_index)
 666 {
 667         struct rev_info rev;
 668         struct setup_revision_opt opt;
 669         unsigned has_changes;
 670
 671         repo_init_revisions(r, &rev, NULL);
 672         memset(&opt, 0, sizeof(opt));
 673         opt.def = def;
 674         setup_revisions(0, NULL, &rev, &opt);
 675         rev.diffopt.flags.quick = 1;
 676         rev.diffopt.flags.exit_with_status = 1;
 677         if (flags) {
 678                 diff_flags_or(&rev.diffopt.flags, flags);
 679                 /*
 680                  * Now that flags are merged, honor override_submodule_config
 681                  * and ignore_submodules from passed flags.
 682                  */
 683                 if (flags->override_submodule_config)
 684                         rev.diffopt.flags.ignore_submodules = flags->ignore_submodules;
 685         }
 686         rev.diffopt.ita_invisible_in_index = ita_invisible_in_index;
 687         run_diff_index(&rev, DIFF_INDEX_CACHED);
 688         has_changes = rev.diffopt.flags.has_changes;
 689         release_revisions(&rev);
 690         return (has_changes != 0);
 691 }
 692
 693 static struct strbuf *idiff_prefix_cb(struct diff_options *opt UNUSED, void *data)
 694 {
 695         return data;
 696 }
 697
 698 void show_interdiff(const struct object_id *oid1, const struct object_id *oid2,
 699                     int indent, struct diff_options *diffopt)
 700 {
 701         struct diff_options opts;
 702         struct strbuf prefix = STRBUF_INIT;
 703
 704         memcpy(&opts, diffopt, sizeof(opts));
 705         opts.output_format = DIFF_FORMAT_PATCH;
 706         opts.output_prefix = idiff_prefix_cb;
 707         strbuf_addchars(&prefix, ' ', indent);
 708         opts.output_prefix_data = &prefix;
 709         diff_setup_done(&opts);
 710
 711         diff_tree_oid(oid1, oid2, "", &opts);
 712         diffcore_std(&opts);
 713         diff_flush(&opts);
 714
 715         strbuf_release(&prefix);
 716 }