diff-lib.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4
   5 #define USE_THE_REPOSITORY_VARIABLE
   6 #define DISABLE_SIGN_COMPARE_WARNINGS
   7
   8 #include "git-compat-util.h"
   9 #include "commit.h"
  10 #include "diff.h"
  11 #include "diffcore.h"
  12 #include "gettext.h"
  13 #include "hash.h"
  14 #include "hex.h"
  15 #include "object-name.h"
  16 #include "read-cache.h"
  17 #include "revision.h"
  18 #include "cache-tree.h"
  19 #include "unpack-trees.h"
  20 #include "refs.h"
  21 #include "repository.h"
  22 #include "submodule.h"
  23 #include "symlinks.h"
  24 #include "trace.h"
  25 #include "dir.h"
  26 #include "fsmonitor.h"
  27 #include "commit-reach.h"
  28
  29 /*
  30  * diff-files
  31  */
  32
  33 /*
  34  * Has the work tree entity been removed?
  35  *
  36  * Return 1 if it was removed from the work tree, 0 if an entity to be
  37  * compared with the cache entry ce still exists (the latter includes
  38  * the case where a directory that is not a submodule repository
  39  * exists for ce that is a submodule -- it is a submodule that is not
  40  * checked out).  Return negative for an error.
  41  */
  42 static int check_removed(const struct cache_entry *ce, struct stat *st)
  43 {
  44         int stat_err;
  45
  46         if (!(ce->ce_flags & CE_FSMONITOR_VALID))
  47                 stat_err = lstat(ce->name, st);
  48         else
  49                 stat_err = fake_lstat(ce, st);
  50         if (stat_err < 0) {
  51                 if (!is_missing_file_error(errno))
  52                         return -1;
  53                 return 1;
  54         }
  55
  56         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
  57                 return 1;
  58         if (S_ISDIR(st->st_mode)) {
  59                 struct object_id sub;
  60
  61                 /*
  62                  * If ce is already a gitlink, we can have a plain
  63                  * directory (i.e. the submodule is not checked out),
  64                  * or a checked out submodule.  Either case this is not
  65                  * a case where something was removed from the work tree,
  66                  * so we will return 0.
  67                  *
  68                  * Otherwise, if the directory is not a submodule
  69                  * repository, that means ce which was a blob turned into
  70                  * a directory --- the blob was removed!
  71                  */
  72                 if (!S_ISGITLINK(ce->ce_mode) &&
  73                     repo_resolve_gitlink_ref(the_repository, ce->name,
  74                                              "HEAD", &sub))
  75                         return 1;
  76         }
  77         return 0;
  78 }
  79
  80 /*
  81  * Has a file changed or has a submodule new commits or a dirty work tree?
  82  *
  83  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
  84  * option is set, the caller does not only want to know if a submodule is
  85  * modified at all but wants to know all the conditions that are met (new
  86  * commits, untracked content and/or modified content).
  87  */
  88 static int match_stat_with_submodule(struct diff_options *diffopt,
  89                                      const struct cache_entry *ce,
  90                                      struct stat *st, unsigned ce_option,
  91                                      unsigned *dirty_submodule)
  92 {
  93         int changed = ie_match_stat(diffopt->repo->index, ce, st, ce_option);
  94         if (S_ISGITLINK(ce->ce_mode)) {
  95                 struct diff_flags orig_flags = diffopt->flags;
  96                 if (!diffopt->flags.override_submodule_config)
  97                         set_diffopt_flags_from_submodule_config(diffopt, ce->name);
  98                 if (diffopt->flags.ignore_submodules)
  99                         changed = 0;
 100                 else if (!diffopt->flags.ignore_dirty_submodules &&
 101                          (!changed || diffopt->flags.dirty_submodules))
 102                         *dirty_submodule = is_submodule_modified(ce->name,
 103                                                                  diffopt->flags.ignore_untracked_in_submodules);
 104                 diffopt->flags = orig_flags;
 105         }
 106         return changed;
 107 }
 108
 109 void run_diff_files(struct rev_info *revs, unsigned int option)
 110 {
 111         int entries, i;
 112         int diff_unmerged_stage = revs->max_count;
 113         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
 114                               ? CE_MATCH_RACY_IS_DIRTY : 0);
 115         uint64_t start = getnanotime();
 116         struct index_state *istate = revs->diffopt.repo->index;
 117
 118         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
 119
 120         refresh_fsmonitor(istate);
 121
 122         if (diff_unmerged_stage < 0)
 123                 diff_unmerged_stage = 2;
 124         entries = istate->cache_nr;
 125         for (i = 0; i < entries; i++) {
 126                 unsigned int oldmode, newmode;
 127                 struct cache_entry *ce = istate->cache[i];
 128                 int changed;
 129                 unsigned dirty_submodule = 0;
 130                 const struct object_id *old_oid, *new_oid;
 131
 132                 if (diff_can_quit_early(&revs->diffopt))
 133                         break;
 134
 135                 /*
 136                  * NEEDSWORK:
 137                  * Here we filter with pathspec but the result is further
 138                  * filtered out when --relative is in effect.  To end-users,
 139                  * a pathspec element that matched only to paths outside the
 140                  * current directory is like not matching anything at all;
 141                  * the handling of ps_matched[] here may become problematic
 142                  * if/when we add the "--error-unmatch" option to "git diff".
 143                  */
 144                 if (!ce_path_match(istate, ce, &revs->prune_data, revs->ps_matched))
 145                         continue;
 146
 147                 if (revs->diffopt.prefix &&
 148                     strncmp(ce->name, revs->diffopt.prefix, revs->diffopt.prefix_length))
 149                         continue;
 150
 151                 if (ce_stage(ce)) {
 152                         struct combine_diff_path *dpath;
 153                         struct diff_filepair *pair;
 154                         unsigned int wt_mode = 0;
 155                         int num_compare_stages = 0;
 156                         struct stat st;
 157
 158                         changed = check_removed(ce, &st);
 159                         if (!changed)
 160                                 wt_mode = ce_mode_from_stat(ce, st.st_mode);
 161                         else {
 162                                 if (changed < 0) {
 163                                         perror(ce->name);
 164                                         continue;
 165                                 }
 166                                 wt_mode = 0;
 167                         }
 168
 169                         /*
 170                          * Allocate space for two parents, which will come from
 171                          * index stages #2 and #3, if present. Below we'll fill
 172                          * these from (stage - 2).
 173                          */
 174                         dpath = combine_diff_path_new(ce->name, ce_namelen(ce),
 175                                                       wt_mode, null_oid(the_hash_algo), 2);
 176
 177                         while (i < entries) {
 178                                 struct cache_entry *nce = istate->cache[i];
 179                                 int stage;
 180
 181                                 if (strcmp(ce->name, nce->name))
 182                                         break;
 183
 184                                 /* Stage #2 (ours) is the first parent,
 185                                  * stage #3 (theirs) is the second.
 186                                  */
 187                                 stage = ce_stage(nce);
 188                                 if (2 <= stage) {
 189                                         int mode = nce->ce_mode;
 190                                         num_compare_stages++;
 191                                         oidcpy(&dpath->parent[stage - 2].oid,
 192                                                &nce->oid);
 193                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 194                                         dpath->parent[stage-2].status =
 195                                                 DIFF_STATUS_MODIFIED;
 196                                 }
 197
 198                                 /* diff against the proper unmerged stage */
 199                                 if (stage == diff_unmerged_stage)
 200                                         ce = nce;
 201                                 i++;
 202                         }
 203                         /*
 204                          * Compensate for loop update
 205                          */
 206                         i--;
 207
 208                         if (revs->combine_merges && num_compare_stages == 2) {
 209                                 show_combined_diff(dpath, 2, revs);
 210                                 free(dpath);
 211                                 continue;
 212                         }
 213                         FREE_AND_NULL(dpath);
 214
 215                         /*
 216                          * Show the diff for the 'ce' if we found the one
 217                          * from the desired stage.
 218                          */
 219                         pair = diff_unmerge(&revs->diffopt, ce->name);
 220                         if (wt_mode)
 221                                 pair->two->mode = wt_mode;
 222                         if (ce_stage(ce) != diff_unmerged_stage)
 223                                 continue;
 224                 }
 225
 226                 if (ce_uptodate(ce) || ce_skip_worktree(ce))
 227                         continue;
 228
 229                 /*
 230                  * When CE_VALID is set (via "update-index --assume-unchanged"
 231                  * or via adding paths while core.ignorestat is set to true),
 232                  * the user has promised that the working tree file for that
 233                  * path will not be modified.  When CE_FSMONITOR_VALID is true,
 234                  * the fsmonitor knows that the path hasn't been modified since
 235                  * we refreshed the cached stat information.  In either case,
 236                  * we do not have to stat to see if the path has been removed
 237                  * or modified.
 238                  */
 239                 if (ce->ce_flags & (CE_VALID | CE_FSMONITOR_VALID)) {
 240                         changed = 0;
 241                         newmode = ce->ce_mode;
 242                 } else {
 243                         struct stat st;
 244
 245                         changed = check_removed(ce, &st);
 246                         if (changed) {
 247                                 if (changed < 0) {
 248                                         perror(ce->name);
 249                                         continue;
 250                                 }
 251                                 diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 252                                                &ce->oid,
 253                                                !is_null_oid(&ce->oid),
 254                                                ce->name, 0);
 255                                 continue;
 256                         } else if (revs->diffopt.ita_invisible_in_index &&
 257                                    ce_intent_to_add(ce)) {
 258                                 newmode = ce_mode_from_stat(ce, st.st_mode);
 259                                 diff_addremove(&revs->diffopt, '+', newmode,
 260                                                null_oid(the_hash_algo), 0, ce->name, 0);
 261                                 continue;
 262                         }
 263
 264                         changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
 265                                                             ce_option, &dirty_submodule);
 266                         newmode = ce_mode_from_stat(ce, st.st_mode);
 267                 }
 268
 269                 if (!changed && !dirty_submodule) {
 270                         ce_mark_uptodate(ce);
 271                         mark_fsmonitor_valid(istate, ce);
 272                         if (!revs->diffopt.flags.find_copies_harder)
 273                                 continue;
 274                 }
 275                 oldmode = ce->ce_mode;
 276                 old_oid = &ce->oid;
 277                 new_oid = changed ? null_oid(the_hash_algo) : &ce->oid;
 278                 diff_change(&revs->diffopt, oldmode, newmode,
 279                             old_oid, new_oid,
 280                             !is_null_oid(old_oid),
 281                             !is_null_oid(new_oid),
 282                             ce->name, 0, dirty_submodule);
 283
 284         }
 285         diffcore_std(&revs->diffopt);
 286         diff_flush(&revs->diffopt);
 287         trace_performance_since(start, "diff-files");
 288 }
 289
 290 /*
 291  * diff-index
 292  */
 293
 294 /* A file entry went away or appeared */
 295 static void diff_index_show_file(struct rev_info *revs,
 296                                  const char *prefix,
 297                                  const struct cache_entry *ce,
 298                                  const struct object_id *oid, int oid_valid,
 299                                  unsigned int mode,
 300                                  unsigned dirty_submodule)
 301 {
 302         diff_addremove(&revs->diffopt, prefix[0], mode,
 303                        oid, oid_valid, ce->name, dirty_submodule);
 304 }
 305
 306 static int get_stat_data(const struct cache_entry *ce,
 307                          const struct object_id **oidp,
 308                          unsigned int *modep,
 309                          int cached, int match_missing,
 310                          unsigned *dirty_submodule, struct diff_options *diffopt)
 311 {
 312         const struct object_id *oid = &ce->oid;
 313         unsigned int mode = ce->ce_mode;
 314
 315         if (!cached && !ce_uptodate(ce)) {
 316                 int changed;
 317                 struct stat st;
 318                 changed = check_removed(ce, &st);
 319                 if (changed < 0)
 320                         return -1;
 321                 else if (changed) {
 322                         if (match_missing) {
 323                                 *oidp = oid;
 324                                 *modep = mode;
 325                                 return 0;
 326                         }
 327                         return -1;
 328                 }
 329                 changed = match_stat_with_submodule(diffopt, ce, &st,
 330                                                     0, dirty_submodule);
 331                 if (changed) {
 332                         mode = ce_mode_from_stat(ce, st.st_mode);
 333                         oid = null_oid(the_hash_algo);
 334                 }
 335         }
 336
 337         *oidp = oid;
 338         *modep = mode;
 339         return 0;
 340 }
 341
 342 static void show_new_file(struct rev_info *revs,
 343                           const struct cache_entry *new_file,
 344                           int cached, int match_missing)
 345 {
 346         const struct object_id *oid;
 347         unsigned int mode;
 348         unsigned dirty_submodule = 0;
 349
 350         if (new_file && S_ISSPARSEDIR(new_file->ce_mode)) {
 351                 diff_tree_oid(NULL, &new_file->oid, new_file->name, &revs->diffopt);
 352                 return;
 353         }
 354
 355         /*
 356          * New file in the index: it might actually be different in
 357          * the working tree.
 358          */
 359         if (get_stat_data(new_file, &oid, &mode, cached, match_missing,
 360             &dirty_submodule, &revs->diffopt) < 0)
 361                 return;
 362
 363         diff_index_show_file(revs, "+", new_file, oid, !is_null_oid(oid), mode, dirty_submodule);
 364 }
 365
 366 static int show_modified(struct rev_info *revs,
 367                          const struct cache_entry *old_entry,
 368                          const struct cache_entry *new_entry,
 369                          int report_missing,
 370                          int cached, int match_missing)
 371 {
 372         unsigned int mode, oldmode;
 373         const struct object_id *oid;
 374         unsigned dirty_submodule = 0;
 375
 376         assert(S_ISSPARSEDIR(old_entry->ce_mode) ==
 377                S_ISSPARSEDIR(new_entry->ce_mode));
 378
 379         /*
 380          * If both are sparse directory entries, then expand the
 381          * modifications to the file level. If only one was a sparse
 382          * directory, then they appear as an add and delete instead of
 383          * a modification.
 384          */
 385         if (S_ISSPARSEDIR(new_entry->ce_mode)) {
 386                 diff_tree_oid(&old_entry->oid, &new_entry->oid, new_entry->name, &revs->diffopt);
 387                 return 0;
 388         }
 389
 390         if (get_stat_data(new_entry, &oid, &mode, cached, match_missing,
 391                           &dirty_submodule, &revs->diffopt) < 0) {
 392                 if (report_missing)
 393                         diff_index_show_file(revs, "-", old_entry,
 394                                              &old_entry->oid, 1, old_entry->ce_mode,
 395                                              0);
 396                 return -1;
 397         }
 398
 399         if (revs->combine_merges && !cached &&
 400             (!oideq(oid, &old_entry->oid) || !oideq(&old_entry->oid, &new_entry->oid))) {
 401                 struct combine_diff_path *p;
 402
 403                 p = combine_diff_path_new(new_entry->name,
 404                                           ce_namelen(new_entry),
 405                                           mode, null_oid(the_hash_algo), 2);
 406                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 407                 p->parent[0].mode = new_entry->ce_mode;
 408                 oidcpy(&p->parent[0].oid, &new_entry->oid);
 409                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 410                 p->parent[1].mode = old_entry->ce_mode;
 411                 oidcpy(&p->parent[1].oid, &old_entry->oid);
 412                 show_combined_diff(p, 2, revs);
 413                 free(p);
 414                 return 0;
 415         }
 416
 417         oldmode = old_entry->ce_mode;
 418         if (mode == oldmode && oideq(oid, &old_entry->oid) && !dirty_submodule &&
 419             !revs->diffopt.flags.find_copies_harder)
 420                 return 0;
 421
 422         diff_change(&revs->diffopt, oldmode, mode,
 423                     &old_entry->oid, oid, 1, !is_null_oid(oid),
 424                     old_entry->name, 0, dirty_submodule);
 425         return 0;
 426 }
 427
 428 /*
 429  * This gets a mix of an existing index and a tree, one pathname entry
 430  * at a time. The index entry may be a single stage-0 one, but it could
 431  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 432  * give you the position and number of entries in the index).
 433  */
 434 static void do_oneway_diff(struct unpack_trees_options *o,
 435                            const struct cache_entry *idx,
 436                            const struct cache_entry *tree)
 437 {
 438         struct rev_info *revs = o->unpack_data;
 439         int match_missing, cached;
 440
 441         /*
 442          * i-t-a entries do not actually exist in the index (if we're
 443          * looking at its content)
 444          */
 445         if (o->index_only &&
 446             revs->diffopt.ita_invisible_in_index &&
 447             idx && ce_intent_to_add(idx)) {
 448                 idx = NULL;
 449                 if (!tree)
 450                         return; /* nothing to diff.. */
 451         }
 452
 453         /* if the entry is not checked out, don't examine work tree */
 454         cached = o->index_only ||
 455                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
 456
 457         match_missing = revs->match_missing;
 458
 459         if (cached && idx && ce_stage(idx)) {
 460                 struct diff_filepair *pair;
 461                 pair = diff_unmerge(&revs->diffopt, idx->name);
 462                 if (tree)
 463                         fill_filespec(pair->one, &tree->oid, 1,
 464                                       tree->ce_mode);
 465                 return;
 466         }
 467
 468         /*
 469          * Something added to the tree?
 470          */
 471         if (!tree) {
 472                 show_new_file(revs, idx, cached, match_missing);
 473                 return;
 474         }
 475
 476         /*
 477          * Something removed from the tree?
 478          */
 479         if (!idx) {
 480                 if (S_ISSPARSEDIR(tree->ce_mode)) {
 481                         diff_tree_oid(&tree->oid, NULL, tree->name, &revs->diffopt);
 482                         return;
 483                 }
 484
 485                 diff_index_show_file(revs, "-", tree, &tree->oid, 1,
 486                                      tree->ce_mode, 0);
 487                 return;
 488         }
 489
 490         /* Show difference between old and new */
 491         show_modified(revs, tree, idx, 1, cached, match_missing);
 492 }
 493
 494 /*
 495  * The unpack_trees() interface is designed for merging, so
 496  * the different source entries are designed primarily for
 497  * the source trees, with the old index being really mainly
 498  * used for being replaced by the result.
 499  *
 500  * For diffing, the index is more important, and we only have a
 501  * single tree.
 502  *
 503  * We're supposed to advance o->pos to skip what we have already processed.
 504  *
 505  * This wrapper makes it all more readable, and takes care of all
 506  * the fairly complex unpack_trees() semantic requirements, including
 507  * the skipping, the path matching, the type conflict cases etc.
 508  */
 509 static int oneway_diff(const struct cache_entry * const *src,
 510                        struct unpack_trees_options *o)
 511 {
 512         const struct cache_entry *idx = src[0];
 513         const struct cache_entry *tree = src[1];
 514         struct rev_info *revs = o->unpack_data;
 515
 516         /*
 517          * Unpack-trees generates a DF/conflict entry if
 518          * there was a directory in the index and a tree
 519          * in the tree. From a diff standpoint, that's a
 520          * delete of the tree and a create of the file.
 521          */
 522         if (tree == o->df_conflict_entry)
 523                 tree = NULL;
 524
 525         if (ce_path_match(revs->diffopt.repo->index,
 526                           idx ? idx : tree,
 527                           &revs->prune_data, NULL)) {
 528                 do_oneway_diff(o, idx, tree);
 529                 if (diff_can_quit_early(&revs->diffopt)) {
 530                         o->exiting_early = 1;
 531                         return -1;
 532                 }
 533         }
 534
 535         return 0;
 536 }
 537
 538 static int diff_cache(struct rev_info *revs,
 539                       const struct object_id *tree_oid,
 540                       const char *tree_name,
 541                       int cached)
 542 {
 543         struct tree *tree;
 544         struct tree_desc t;
 545         struct unpack_trees_options opts;
 546
 547         tree = parse_tree_indirect(tree_oid);
 548         if (!tree)
 549                 return error("bad tree object %s",
 550                              tree_name ? tree_name : oid_to_hex(tree_oid));
 551         memset(&opts, 0, sizeof(opts));
 552         opts.head_idx = 1;
 553         opts.index_only = cached;
 554         opts.diff_index_cached = (cached &&
 555                                   !revs->diffopt.flags.find_copies_harder);
 556         opts.merge = 1;
 557         opts.fn = oneway_diff;
 558         opts.unpack_data = revs;
 559         opts.src_index = revs->diffopt.repo->index;
 560         opts.dst_index = NULL;
 561         opts.pathspec = &revs->diffopt.pathspec;
 562         opts.pathspec->recursive = 1;
 563
 564         init_tree_desc(&t, &tree->object.oid, tree->buffer, tree->size);
 565         return unpack_trees(1, &t, &opts);
 566 }
 567
 568 void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
 569 {
 570         int i;
 571         struct commit *mb_child[2] = {0};
 572         struct commit_list *merge_bases = NULL;
 573
 574         for (i = 0; i < revs->pending.nr; i++) {
 575                 struct object *obj = revs->pending.objects[i].item;
 576                 if (obj->flags)
 577                         die(_("--merge-base does not work with ranges"));
 578         }
 579
 580         /*
 581          * This check must go after the for loop above because A...B
 582          * ranges produce three pending commits, resulting in a
 583          * misleading error message.
 584          */
 585         if (revs->pending.nr < 1 || revs->pending.nr > 2)
 586                 BUG("unexpected revs->pending.nr: %d", revs->pending.nr);
 587
 588         for (i = 0; i < revs->pending.nr; i++)
 589                 mb_child[i] = lookup_commit_reference(the_repository, &revs->pending.objects[i].item->oid);
 590         if (revs->pending.nr == 1) {
 591                 struct object_id oid;
 592
 593                 if (repo_get_oid(the_repository, "HEAD", &oid))
 594                         die(_("unable to get HEAD"));
 595
 596                 mb_child[1] = lookup_commit_reference(the_repository, &oid);
 597         }
 598
 599         if (repo_get_merge_bases(the_repository, mb_child[0], mb_child[1], &merge_bases) < 0)
 600                 exit(128);
 601         if (!merge_bases)
 602                 die(_("no merge base found"));
 603         if (merge_bases->next)
 604                 die(_("multiple merge bases found"));
 605
 606         oidcpy(mb, &merge_bases->item->object.oid);
 607
 608         free_commit_list(merge_bases);
 609 }
 610
 611 void run_diff_index(struct rev_info *revs, unsigned int option)
 612 {
 613         struct object_array_entry *ent;
 614         int cached = !!(option & DIFF_INDEX_CACHED);
 615         int merge_base = !!(option & DIFF_INDEX_MERGE_BASE);
 616         struct object_id oid;
 617         const char *name;
 618         char merge_base_hex[GIT_MAX_HEXSZ + 1];
 619         struct index_state *istate = revs->diffopt.repo->index;
 620
 621         if (revs->pending.nr != 1)
 622                 BUG("run_diff_index must be passed exactly one tree");
 623
 624         trace_performance_enter();
 625         ent = revs->pending.objects;
 626
 627         refresh_fsmonitor(istate);
 628
 629         if (merge_base) {
 630                 diff_get_merge_base(revs, &oid);
 631                 name = oid_to_hex_r(merge_base_hex, &oid);
 632         } else {
 633                 oidcpy(&oid, &ent->item->oid);
 634                 name = ent->name;
 635         }
 636
 637         if (diff_cache(revs, &oid, name, cached))
 638                 exit(128);
 639
 640         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 641         diffcore_fix_diff_index();
 642         diffcore_std(&revs->diffopt);
 643         diff_flush(&revs->diffopt);
 644         trace_performance_leave("diff-index");
 645 }
 646
 647 int do_diff_cache(const struct object_id *tree_oid, struct diff_options *opt)
 648 {
 649         struct rev_info revs;
 650
 651         repo_init_revisions(opt->repo, &revs, NULL);
 652         copy_pathspec(&revs.prune_data, &opt->pathspec);
 653         diff_free(&revs.diffopt);
 654         revs.diffopt = *opt;
 655         revs.diffopt.no_free = 1;
 656
 657         if (diff_cache(&revs, tree_oid, NULL, 1))
 658                 exit(128);
 659
 660         release_revisions(&revs);
 661         return 0;
 662 }
 663
 664 int index_differs_from(struct repository *r,
 665                        const char *def, const struct diff_flags *flags,
 666                        int ita_invisible_in_index)
 667 {
 668         struct rev_info rev;
 669         struct setup_revision_opt opt;
 670         unsigned has_changes;
 671
 672         repo_init_revisions(r, &rev, NULL);
 673         memset(&opt, 0, sizeof(opt));
 674         opt.def = def;
 675         setup_revisions(0, NULL, &rev, &opt);
 676         rev.diffopt.flags.quick = 1;
 677         rev.diffopt.flags.exit_with_status = 1;
 678         if (flags) {
 679                 diff_flags_or(&rev.diffopt.flags, flags);
 680                 /*
 681                  * Now that flags are merged, honor override_submodule_config
 682                  * and ignore_submodules from passed flags.
 683                  */
 684                 if (flags->override_submodule_config)
 685                         rev.diffopt.flags.ignore_submodules = flags->ignore_submodules;
 686         }
 687         rev.diffopt.ita_invisible_in_index = ita_invisible_in_index;
 688         run_diff_index(&rev, DIFF_INDEX_CACHED);
 689         has_changes = rev.diffopt.flags.has_changes;
 690         release_revisions(&rev);
 691         return (has_changes != 0);
 692 }
 693
 694 static const char *idiff_prefix_cb(struct diff_options *opt UNUSED, void *data)
 695 {
 696         return data;
 697 }
 698
 699 void show_interdiff(const struct object_id *oid1, const struct object_id *oid2,
 700                     int indent, struct diff_options *diffopt)
 701 {
 702         struct diff_options opts;
 703         struct strbuf prefix = STRBUF_INIT;
 704
 705         memcpy(&opts, diffopt, sizeof(opts));
 706         opts.output_format = DIFF_FORMAT_PATCH;
 707         opts.output_prefix = idiff_prefix_cb;
 708         strbuf_addchars(&prefix, ' ', indent);
 709         opts.output_prefix_data = prefix.buf;
 710         diff_setup_done(&opts);
 711
 712         diff_tree_oid(oid1, oid2, "", &opts);
 713         diffcore_std(&opts);
 714         diff_flush(&opts);
 715
 716         strbuf_release(&prefix);
 717 }