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 "unpack-trees.h"
  12 #include "refs.h"
  13 #include "submodule.h"
  14
  15 /*
  16  * diff-files
  17  */
  18
  19 /*
  20  * Has the work tree entity been removed?
  21  *
  22  * Return 1 if it was removed from the work tree, 0 if an entity to be
  23  * compared with the cache entry ce still exists (the latter includes
  24  * the case where a directory that is not a submodule repository
  25  * exists for ce that is a submodule -- it is a submodule that is not
  26  * checked out).  Return negative for an error.
  27  */
  28 static int check_removed(const struct cache_entry *ce, struct stat *st)
  29 {
  30         if (lstat(ce->name, st) < 0) {
  31                 if (errno != ENOENT && errno != ENOTDIR)
  32                         return -1;
  33                 return 1;
  34         }
  35         if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
  36                 return 1;
  37         if (S_ISDIR(st->st_mode)) {
  38                 unsigned char sub[20];
  39
  40                 /*
  41                  * If ce is already a gitlink, we can have a plain
  42                  * directory (i.e. the submodule is not checked out),
  43                  * or a checked out submodule.  Either case this is not
  44                  * a case where something was removed from the work tree,
  45                  * so we will return 0.
  46                  *
  47                  * Otherwise, if the directory is not a submodule
  48                  * repository, that means ce which was a blob turned into
  49                  * a directory --- the blob was removed!
  50                  */
  51                 if (!S_ISGITLINK(ce->ce_mode) &&
  52                     resolve_gitlink_ref(ce->name, "HEAD", sub))
  53                         return 1;
  54         }
  55         return 0;
  56 }
  57
  58 /*
  59  * Has a file changed or has a submodule new commits or a dirty work tree?
  60  *
  61  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
  62  * option is set, the caller does not only want to know if a submodule is
  63  * modified at all but wants to know all the conditions that are met (new
  64  * commits, untracked content and/or modified content).
  65  */
  66 static int match_stat_with_submodule(struct diff_options *diffopt,
  67                                       struct cache_entry *ce, struct stat *st,
  68                                       unsigned ce_option, unsigned *dirty_submodule)
  69 {
  70         int changed = ce_match_stat(ce, st, ce_option);
  71         if (S_ISGITLINK(ce->ce_mode)
  72             && !DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES)
  73             && (!changed || DIFF_OPT_TST(diffopt, DIRTY_SUBMODULES))) {
  74                 *dirty_submodule = is_submodule_modified(ce->name);
  75         }
  76         return changed;
  77 }
  78
  79 int run_diff_files(struct rev_info *revs, unsigned int option)
  80 {
  81         int entries, i;
  82         int diff_unmerged_stage = revs->max_count;
  83         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
  84         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
  85                               ? CE_MATCH_RACY_IS_DIRTY : 0);
  86
  87         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
  88
  89         if (diff_unmerged_stage < 0)
  90                 diff_unmerged_stage = 2;
  91         entries = active_nr;
  92         for (i = 0; i < entries; i++) {
  93                 struct stat st;
  94                 unsigned int oldmode, newmode;
  95                 struct cache_entry *ce = active_cache[i];
  96                 int changed;
  97                 unsigned dirty_submodule = 0;
  98
  99                 if (DIFF_OPT_TST(&revs->diffopt, QUICK) &&
 100                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
 101                         break;
 102
 103                 if (!ce_path_match(ce, revs->prune_data))
 104                         continue;
 105
 106                 if (ce_stage(ce)) {
 107                         struct combine_diff_path *dpath;
 108                         int num_compare_stages = 0;
 109                         size_t path_len;
 110
 111                         path_len = ce_namelen(ce);
 112
 113                         dpath = xmalloc(combine_diff_path_size(5, path_len));
 114                         dpath->path = (char *) &(dpath->parent[5]);
 115
 116                         dpath->next = NULL;
 117                         dpath->len = path_len;
 118                         memcpy(dpath->path, ce->name, path_len);
 119                         dpath->path[path_len] = '\0';
 120                         hashclr(dpath->sha1);
 121                         memset(&(dpath->parent[0]), 0,
 122                                sizeof(struct combine_diff_parent)*5);
 123
 124                         changed = check_removed(ce, &st);
 125                         if (!changed)
 126                                 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
 127                         else {
 128                                 if (changed < 0) {
 129                                         perror(ce->name);
 130                                         continue;
 131                                 }
 132                                 if (silent_on_removed)
 133                                         continue;
 134                         }
 135
 136                         while (i < entries) {
 137                                 struct cache_entry *nce = active_cache[i];
 138                                 int stage;
 139
 140                                 if (strcmp(ce->name, nce->name))
 141                                         break;
 142
 143                                 /* Stage #2 (ours) is the first parent,
 144                                  * stage #3 (theirs) is the second.
 145                                  */
 146                                 stage = ce_stage(nce);
 147                                 if (2 <= stage) {
 148                                         int mode = nce->ce_mode;
 149                                         num_compare_stages++;
 150                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 151                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 152                                         dpath->parent[stage-2].status =
 153                                                 DIFF_STATUS_MODIFIED;
 154                                 }
 155
 156                                 /* diff against the proper unmerged stage */
 157                                 if (stage == diff_unmerged_stage)
 158                                         ce = nce;
 159                                 i++;
 160                         }
 161                         /*
 162                          * Compensate for loop update
 163                          */
 164                         i--;
 165
 166                         if (revs->combine_merges && num_compare_stages == 2) {
 167                                 show_combined_diff(dpath, 2,
 168                                                    revs->dense_combined_merges,
 169                                                    revs);
 170                                 free(dpath);
 171                                 continue;
 172                         }
 173                         free(dpath);
 174                         dpath = NULL;
 175
 176                         /*
 177                          * Show the diff for the 'ce' if we found the one
 178                          * from the desired stage.
 179                          */
 180                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
 181                         if (ce_stage(ce) != diff_unmerged_stage)
 182                                 continue;
 183                 }
 184
 185                 if (ce_uptodate(ce) || ce_skip_worktree(ce))
 186                         continue;
 187
 188                 /* If CE_VALID is set, don't look at workdir for file removal */
 189                 changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
 190                 if (changed) {
 191                         if (changed < 0) {
 192                                 perror(ce->name);
 193                                 continue;
 194                         }
 195                         if (silent_on_removed)
 196                                 continue;
 197                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 198                                        ce->sha1, ce->name, 0);
 199                         continue;
 200                 }
 201                 changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
 202                                                     ce_option, &dirty_submodule);
 203                 if (!changed && !dirty_submodule) {
 204                         ce_mark_uptodate(ce);
 205                         if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 206                                 continue;
 207                 }
 208                 oldmode = ce->ce_mode;
 209                 newmode = ce_mode_from_stat(ce, st.st_mode);
 210                 diff_change(&revs->diffopt, oldmode, newmode,
 211                             ce->sha1, (changed ? null_sha1 : ce->sha1),
 212                             ce->name, 0, dirty_submodule);
 213
 214         }
 215         diffcore_std(&revs->diffopt);
 216         diff_flush(&revs->diffopt);
 217         return 0;
 218 }
 219
 220 /*
 221  * diff-index
 222  */
 223
 224 /* A file entry went away or appeared */
 225 static void diff_index_show_file(struct rev_info *revs,
 226                                  const char *prefix,
 227                                  struct cache_entry *ce,
 228                                  const unsigned char *sha1, unsigned int mode,
 229                                  unsigned dirty_submodule)
 230 {
 231         diff_addremove(&revs->diffopt, prefix[0], mode,
 232                        sha1, ce->name, dirty_submodule);
 233 }
 234
 235 static int get_stat_data(struct cache_entry *ce,
 236                          const unsigned char **sha1p,
 237                          unsigned int *modep,
 238                          int cached, int match_missing,
 239                          unsigned *dirty_submodule, struct diff_options *diffopt)
 240 {
 241         const unsigned char *sha1 = ce->sha1;
 242         unsigned int mode = ce->ce_mode;
 243
 244         if (!cached && !ce_uptodate(ce)) {
 245                 int changed;
 246                 struct stat st;
 247                 changed = check_removed(ce, &st);
 248                 if (changed < 0)
 249                         return -1;
 250                 else if (changed) {
 251                         if (match_missing) {
 252                                 *sha1p = sha1;
 253                                 *modep = mode;
 254                                 return 0;
 255                         }
 256                         return -1;
 257                 }
 258                 changed = match_stat_with_submodule(diffopt, ce, &st,
 259                                                     0, dirty_submodule);
 260                 if (changed) {
 261                         mode = ce_mode_from_stat(ce, st.st_mode);
 262                         sha1 = null_sha1;
 263                 }
 264         }
 265
 266         *sha1p = sha1;
 267         *modep = mode;
 268         return 0;
 269 }
 270
 271 static void show_new_file(struct rev_info *revs,
 272                           struct cache_entry *new,
 273                           int cached, int match_missing)
 274 {
 275         const unsigned char *sha1;
 276         unsigned int mode;
 277         unsigned dirty_submodule = 0;
 278
 279         /*
 280          * New file in the index: it might actually be different in
 281          * the working copy.
 282          */
 283         if (get_stat_data(new, &sha1, &mode, cached, match_missing,
 284             &dirty_submodule, &revs->diffopt) < 0)
 285                 return;
 286
 287         diff_index_show_file(revs, "+", new, sha1, mode, dirty_submodule);
 288 }
 289
 290 static int show_modified(struct rev_info *revs,
 291                          struct cache_entry *old,
 292                          struct cache_entry *new,
 293                          int report_missing,
 294                          int cached, int match_missing)
 295 {
 296         unsigned int mode, oldmode;
 297         const unsigned char *sha1;
 298         unsigned dirty_submodule = 0;
 299
 300         if (get_stat_data(new, &sha1, &mode, cached, match_missing,
 301                           &dirty_submodule, &revs->diffopt) < 0) {
 302                 if (report_missing)
 303                         diff_index_show_file(revs, "-", old,
 304                                              old->sha1, old->ce_mode, 0);
 305                 return -1;
 306         }
 307
 308         if (revs->combine_merges && !cached &&
 309             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 310                 struct combine_diff_path *p;
 311                 int pathlen = ce_namelen(new);
 312
 313                 p = xmalloc(combine_diff_path_size(2, pathlen));
 314                 p->path = (char *) &p->parent[2];
 315                 p->next = NULL;
 316                 p->len = pathlen;
 317                 memcpy(p->path, new->name, pathlen);
 318                 p->path[pathlen] = 0;
 319                 p->mode = mode;
 320                 hashclr(p->sha1);
 321                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 322                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 323                 p->parent[0].mode = new->ce_mode;
 324                 hashcpy(p->parent[0].sha1, new->sha1);
 325                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 326                 p->parent[1].mode = old->ce_mode;
 327                 hashcpy(p->parent[1].sha1, old->sha1);
 328                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 329                 free(p);
 330                 return 0;
 331         }
 332
 333         oldmode = old->ce_mode;
 334         if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
 335             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 336                 return 0;
 337
 338         diff_change(&revs->diffopt, oldmode, mode,
 339                     old->sha1, sha1, old->name, 0, dirty_submodule);
 340         return 0;
 341 }
 342
 343 /*
 344  * This gets a mix of an existing index and a tree, one pathname entry
 345  * at a time. The index entry may be a single stage-0 one, but it could
 346  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 347  * give you the position and number of entries in the index).
 348  */
 349 static void do_oneway_diff(struct unpack_trees_options *o,
 350         struct cache_entry *idx,
 351         struct cache_entry *tree)
 352 {
 353         struct rev_info *revs = o->unpack_data;
 354         int match_missing, cached;
 355
 356         /* if the entry is not checked out, don't examine work tree */
 357         cached = o->index_only ||
 358                 (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
 359         /*
 360          * Backward compatibility wart - "diff-index -m" does
 361          * not mean "do not ignore merges", but "match_missing".
 362          *
 363          * But with the revision flag parsing, that's found in
 364          * "!revs->ignore_merges".
 365          */
 366         match_missing = !revs->ignore_merges;
 367
 368         if (cached && idx && ce_stage(idx)) {
 369                 diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode,
 370                              idx->sha1);
 371                 return;
 372         }
 373
 374         /*
 375          * Something added to the tree?
 376          */
 377         if (!tree) {
 378                 show_new_file(revs, idx, cached, match_missing);
 379                 return;
 380         }
 381
 382         /*
 383          * Something removed from the tree?
 384          */
 385         if (!idx) {
 386                 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode, 0);
 387                 return;
 388         }
 389
 390         /* Show difference between old and new */
 391         show_modified(revs, tree, idx, 1, cached, match_missing);
 392 }
 393
 394 /*
 395  * The unpack_trees() interface is designed for merging, so
 396  * the different source entries are designed primarily for
 397  * the source trees, with the old index being really mainly
 398  * used for being replaced by the result.
 399  *
 400  * For diffing, the index is more important, and we only have a
 401  * single tree.
 402  *
 403  * We're supposed to advance o->pos to skip what we have already processed.
 404  *
 405  * This wrapper makes it all more readable, and takes care of all
 406  * the fairly complex unpack_trees() semantic requirements, including
 407  * the skipping, the path matching, the type conflict cases etc.
 408  */
 409 static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
 410 {
 411         struct cache_entry *idx = src[0];
 412         struct cache_entry *tree = src[1];
 413         struct rev_info *revs = o->unpack_data;
 414
 415         /*
 416          * Unpack-trees generates a DF/conflict entry if
 417          * there was a directory in the index and a tree
 418          * in the tree. From a diff standpoint, that's a
 419          * delete of the tree and a create of the file.
 420          */
 421         if (tree == o->df_conflict_entry)
 422                 tree = NULL;
 423
 424         if (ce_path_match(idx ? idx : tree, revs->prune_data))
 425                 do_oneway_diff(o, idx, tree);
 426
 427         return 0;
 428 }
 429
 430 int run_diff_index(struct rev_info *revs, int cached)
 431 {
 432         struct object *ent;
 433         struct tree *tree;
 434         const char *tree_name;
 435         struct unpack_trees_options opts;
 436         struct tree_desc t;
 437
 438         ent = revs->pending.objects[0].item;
 439         tree_name = revs->pending.objects[0].name;
 440         tree = parse_tree_indirect(ent->sha1);
 441         if (!tree)
 442                 return error("bad tree object %s", tree_name);
 443
 444         memset(&opts, 0, sizeof(opts));
 445         opts.head_idx = 1;
 446         opts.index_only = cached;
 447         opts.diff_index_cached = (cached &&
 448                                   !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
 449         opts.merge = 1;
 450         opts.fn = oneway_diff;
 451         opts.unpack_data = revs;
 452         opts.src_index = &the_index;
 453         opts.dst_index = NULL;
 454
 455         init_tree_desc(&t, tree->buffer, tree->size);
 456         if (unpack_trees(1, &t, &opts))
 457                 exit(128);
 458
 459         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 460         diffcore_fix_diff_index(&revs->diffopt);
 461         diffcore_std(&revs->diffopt);
 462         diff_flush(&revs->diffopt);
 463         return 0;
 464 }
 465
 466 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 467 {
 468         struct tree *tree;
 469         struct rev_info revs;
 470         int i;
 471         struct cache_entry **dst;
 472         struct cache_entry *last = NULL;
 473         struct unpack_trees_options opts;
 474         struct tree_desc t;
 475
 476         /*
 477          * This is used by git-blame to run diff-cache internally;
 478          * it potentially needs to repeatedly run this, so we will
 479          * start by removing the higher order entries the last round
 480          * left behind.
 481          */
 482         dst = active_cache;
 483         for (i = 0; i < active_nr; i++) {
 484                 struct cache_entry *ce = active_cache[i];
 485                 if (ce_stage(ce)) {
 486                         if (last && !strcmp(ce->name, last->name))
 487                                 continue;
 488                         cache_tree_invalidate_path(active_cache_tree,
 489                                                    ce->name);
 490                         last = ce;
 491                         ce->ce_flags |= CE_REMOVE;
 492                 }
 493                 *dst++ = ce;
 494         }
 495         active_nr = dst - active_cache;
 496
 497         init_revisions(&revs, NULL);
 498         revs.prune_data = opt->paths;
 499         tree = parse_tree_indirect(tree_sha1);
 500         if (!tree)
 501                 die("bad tree object %s", sha1_to_hex(tree_sha1));
 502
 503         memset(&opts, 0, sizeof(opts));
 504         opts.head_idx = 1;
 505         opts.index_only = 1;
 506         opts.diff_index_cached = !DIFF_OPT_TST(opt, FIND_COPIES_HARDER);
 507         opts.merge = 1;
 508         opts.fn = oneway_diff;
 509         opts.unpack_data = &revs;
 510         opts.src_index = &the_index;
 511         opts.dst_index = &the_index;
 512
 513         init_tree_desc(&t, tree->buffer, tree->size);
 514         if (unpack_trees(1, &t, &opts))
 515                 exit(128);
 516         return 0;
 517 }
 518
 519 int index_differs_from(const char *def, int diff_flags)
 520 {
 521         struct rev_info rev;
 522
 523         init_revisions(&rev, NULL);
 524         setup_revisions(0, NULL, &rev, def);
 525         DIFF_OPT_SET(&rev.diffopt, QUICK);
 526         DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
 527         rev.diffopt.flags |= diff_flags;
 528         run_diff_index(&rev, 1);
 529         if (rev.pending.alloc)
 530                 free(rev.pending.objects);
 531         return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
 532 }