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
  14 /*
  15  * diff-files
  16  */
  17
  18 /*
  19  * Has the work tree entity been removed?
  20  *
  21  * Return 1 if it was removed from the work tree, 0 if an entity to be
  22  * compared with the cache entry ce still exists (the latter includes
  23  * the case where a directory that is not a submodule repository
  24  * exists for ce that is a submodule -- it is a submodule that is not
  25  * checked out).  Return negative for an error.
  26  */
  27 static int check_removed(const struct cache_entry *ce, struct stat *st)
  28 {
  29         if (lstat(ce->name, st) < 0) {
  30                 if (errno != ENOENT && errno != ENOTDIR)
  31                         return -1;
  32                 return 1;
  33         }
  34         if (has_symlink_leading_path(ce_namelen(ce), ce->name))
  35                 return 1;
  36         if (S_ISDIR(st->st_mode)) {
  37                 unsigned char sub[20];
  38
  39                 /*
  40                  * If ce is already a gitlink, we can have a plain
  41                  * directory (i.e. the submodule is not checked out),
  42                  * or a checked out submodule.  Either case this is not
  43                  * a case where something was removed from the work tree,
  44                  * so we will return 0.
  45                  *
  46                  * Otherwise, if the directory is not a submodule
  47                  * repository, that means ce which was a blob turned into
  48                  * a directory --- the blob was removed!
  49                  */
  50                 if (!S_ISGITLINK(ce->ce_mode) &&
  51                     resolve_gitlink_ref(ce->name, "HEAD", sub))
  52                         return 1;
  53         }
  54         return 0;
  55 }
  56
  57 int run_diff_files(struct rev_info *revs, unsigned int option)
  58 {
  59         int entries, i;
  60         int diff_unmerged_stage = revs->max_count;
  61         int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
  62         unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
  63                               ? CE_MATCH_RACY_IS_DIRTY : 0);
  64         char symcache[PATH_MAX];
  65
  66         diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
  67
  68         if (diff_unmerged_stage < 0)
  69                 diff_unmerged_stage = 2;
  70         entries = active_nr;
  71         symcache[0] = '\0';
  72         for (i = 0; i < entries; i++) {
  73                 struct stat st;
  74                 unsigned int oldmode, newmode;
  75                 struct cache_entry *ce = active_cache[i];
  76                 int changed;
  77
  78                 if (DIFF_OPT_TST(&revs->diffopt, QUIET) &&
  79                         DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
  80                         break;
  81
  82                 if (!ce_path_match(ce, revs->prune_data))
  83                         continue;
  84
  85                 if (ce_stage(ce)) {
  86                         struct combine_diff_path *dpath;
  87                         int num_compare_stages = 0;
  88                         size_t path_len;
  89
  90                         path_len = ce_namelen(ce);
  91
  92                         dpath = xmalloc(combine_diff_path_size(5, path_len));
  93                         dpath->path = (char *) &(dpath->parent[5]);
  94
  95                         dpath->next = NULL;
  96                         dpath->len = path_len;
  97                         memcpy(dpath->path, ce->name, path_len);
  98                         dpath->path[path_len] = '\0';
  99                         hashclr(dpath->sha1);
 100                         memset(&(dpath->parent[0]), 0,
 101                                sizeof(struct combine_diff_parent)*5);
 102
 103                         changed = check_removed(ce, &st);
 104                         if (!changed)
 105                                 dpath->mode = ce_mode_from_stat(ce, st.st_mode);
 106                         else {
 107                                 if (changed < 0) {
 108                                         perror(ce->name);
 109                                         continue;
 110                                 }
 111                                 if (silent_on_removed)
 112                                         continue;
 113                         }
 114
 115                         while (i < entries) {
 116                                 struct cache_entry *nce = active_cache[i];
 117                                 int stage;
 118
 119                                 if (strcmp(ce->name, nce->name))
 120                                         break;
 121
 122                                 /* Stage #2 (ours) is the first parent,
 123                                  * stage #3 (theirs) is the second.
 124                                  */
 125                                 stage = ce_stage(nce);
 126                                 if (2 <= stage) {
 127                                         int mode = nce->ce_mode;
 128                                         num_compare_stages++;
 129                                         hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 130                                         dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
 131                                         dpath->parent[stage-2].status =
 132                                                 DIFF_STATUS_MODIFIED;
 133                                 }
 134
 135                                 /* diff against the proper unmerged stage */
 136                                 if (stage == diff_unmerged_stage)
 137                                         ce = nce;
 138                                 i++;
 139                         }
 140                         /*
 141                          * Compensate for loop update
 142                          */
 143                         i--;
 144
 145                         if (revs->combine_merges && num_compare_stages == 2) {
 146                                 show_combined_diff(dpath, 2,
 147                                                    revs->dense_combined_merges,
 148                                                    revs);
 149                                 free(dpath);
 150                                 continue;
 151                         }
 152                         free(dpath);
 153                         dpath = NULL;
 154
 155                         /*
 156                          * Show the diff for the 'ce' if we found the one
 157                          * from the desired stage.
 158                          */
 159                         diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
 160                         if (ce_stage(ce) != diff_unmerged_stage)
 161                                 continue;
 162                 }
 163
 164                 if (ce_uptodate(ce))
 165                         continue;
 166
 167                 changed = check_removed(ce, &st);
 168                 if (changed) {
 169                         if (changed < 0) {
 170                                 perror(ce->name);
 171                                 continue;
 172                         }
 173                         if (silent_on_removed)
 174                                 continue;
 175                         diff_addremove(&revs->diffopt, '-', ce->ce_mode,
 176                                        ce->sha1, ce->name);
 177                         continue;
 178                 }
 179                 changed = ce_match_stat(ce, &st, ce_option);
 180                 if (!changed) {
 181                         ce_mark_uptodate(ce);
 182                         if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 183                                 continue;
 184                 }
 185                 oldmode = ce->ce_mode;
 186                 newmode = ce_mode_from_stat(ce, st.st_mode);
 187                 diff_change(&revs->diffopt, oldmode, newmode,
 188                             ce->sha1, (changed ? null_sha1 : ce->sha1),
 189                             ce->name);
 190
 191         }
 192         diffcore_std(&revs->diffopt);
 193         diff_flush(&revs->diffopt);
 194         return 0;
 195 }
 196
 197 /*
 198  * diff-index
 199  */
 200
 201 struct oneway_unpack_data {
 202         struct rev_info *revs;
 203         char symcache[PATH_MAX];
 204 };
 205
 206 /* A file entry went away or appeared */
 207 static void diff_index_show_file(struct rev_info *revs,
 208                                  const char *prefix,
 209                                  struct cache_entry *ce,
 210                                  const unsigned char *sha1, unsigned int mode)
 211 {
 212         diff_addremove(&revs->diffopt, prefix[0], mode,
 213                        sha1, ce->name);
 214 }
 215
 216 static int get_stat_data(struct cache_entry *ce,
 217                          const unsigned char **sha1p,
 218                          unsigned int *modep,
 219                          int cached, int match_missing,
 220                          struct oneway_unpack_data *cbdata)
 221 {
 222         const unsigned char *sha1 = ce->sha1;
 223         unsigned int mode = ce->ce_mode;
 224
 225         if (!cached) {
 226                 int changed;
 227                 struct stat st;
 228                 changed = check_removed(ce, &st);
 229                 if (changed < 0)
 230                         return -1;
 231                 else if (changed) {
 232                         if (match_missing) {
 233                                 *sha1p = sha1;
 234                                 *modep = mode;
 235                                 return 0;
 236                         }
 237                         return -1;
 238                 }
 239                 changed = ce_match_stat(ce, &st, 0);
 240                 if (changed) {
 241                         mode = ce_mode_from_stat(ce, st.st_mode);
 242                         sha1 = null_sha1;
 243                 }
 244         }
 245
 246         *sha1p = sha1;
 247         *modep = mode;
 248         return 0;
 249 }
 250
 251 static void show_new_file(struct oneway_unpack_data *cbdata,
 252                           struct cache_entry *new,
 253                           int cached, int match_missing)
 254 {
 255         const unsigned char *sha1;
 256         unsigned int mode;
 257         struct rev_info *revs = cbdata->revs;
 258
 259         /*
 260          * New file in the index: it might actually be different in
 261          * the working copy.
 262          */
 263         if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0)
 264                 return;
 265
 266         diff_index_show_file(revs, "+", new, sha1, mode);
 267 }
 268
 269 static int show_modified(struct oneway_unpack_data *cbdata,
 270                          struct cache_entry *old,
 271                          struct cache_entry *new,
 272                          int report_missing,
 273                          int cached, int match_missing)
 274 {
 275         unsigned int mode, oldmode;
 276         const unsigned char *sha1;
 277         struct rev_info *revs = cbdata->revs;
 278
 279         if (get_stat_data(new, &sha1, &mode, cached, match_missing, cbdata) < 0) {
 280                 if (report_missing)
 281                         diff_index_show_file(revs, "-", old,
 282                                              old->sha1, old->ce_mode);
 283                 return -1;
 284         }
 285
 286         if (revs->combine_merges && !cached &&
 287             (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 288                 struct combine_diff_path *p;
 289                 int pathlen = ce_namelen(new);
 290
 291                 p = xmalloc(combine_diff_path_size(2, pathlen));
 292                 p->path = (char *) &p->parent[2];
 293                 p->next = NULL;
 294                 p->len = pathlen;
 295                 memcpy(p->path, new->name, pathlen);
 296                 p->path[pathlen] = 0;
 297                 p->mode = mode;
 298                 hashclr(p->sha1);
 299                 memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 300                 p->parent[0].status = DIFF_STATUS_MODIFIED;
 301                 p->parent[0].mode = new->ce_mode;
 302                 hashcpy(p->parent[0].sha1, new->sha1);
 303                 p->parent[1].status = DIFF_STATUS_MODIFIED;
 304                 p->parent[1].mode = old->ce_mode;
 305                 hashcpy(p->parent[1].sha1, old->sha1);
 306                 show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 307                 free(p);
 308                 return 0;
 309         }
 310
 311         oldmode = old->ce_mode;
 312         if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
 313             !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
 314                 return 0;
 315
 316         diff_change(&revs->diffopt, oldmode, mode,
 317                     old->sha1, sha1, old->name);
 318         return 0;
 319 }
 320
 321 /*
 322  * This turns all merge entries into "stage 3". That guarantees that
 323  * when we read in the new tree (into "stage 1"), we won't lose sight
 324  * of the fact that we had unmerged entries.
 325  */
 326 static void mark_merge_entries(void)
 327 {
 328         int i;
 329         for (i = 0; i < active_nr; i++) {
 330                 struct cache_entry *ce = active_cache[i];
 331                 if (!ce_stage(ce))
 332                         continue;
 333                 ce->ce_flags |= CE_STAGEMASK;
 334         }
 335 }
 336
 337 /*
 338  * This gets a mix of an existing index and a tree, one pathname entry
 339  * at a time. The index entry may be a single stage-0 one, but it could
 340  * also be multiple unmerged entries (in which case idx_pos/idx_nr will
 341  * give you the position and number of entries in the index).
 342  */
 343 static void do_oneway_diff(struct unpack_trees_options *o,
 344         struct cache_entry *idx,
 345         struct cache_entry *tree)
 346 {
 347         struct oneway_unpack_data *cbdata = o->unpack_data;
 348         struct rev_info *revs = cbdata->revs;
 349         int match_missing, cached;
 350
 351         /*
 352          * Backward compatibility wart - "diff-index -m" does
 353          * not mean "do not ignore merges", but "match_missing".
 354          *
 355          * But with the revision flag parsing, that's found in
 356          * "!revs->ignore_merges".
 357          */
 358         cached = o->index_only;
 359         match_missing = !revs->ignore_merges;
 360
 361         if (cached && idx && ce_stage(idx)) {
 362                 if (tree)
 363                         diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode, idx->sha1);
 364                 return;
 365         }
 366
 367         /*
 368          * Something added to the tree?
 369          */
 370         if (!tree) {
 371                 show_new_file(cbdata, idx, cached, match_missing);
 372                 return;
 373         }
 374
 375         /*
 376          * Something removed from the tree?
 377          */
 378         if (!idx) {
 379                 diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
 380                 return;
 381         }
 382
 383         /* Show difference between old and new */
 384         show_modified(cbdata, tree, idx, 1, cached, match_missing);
 385 }
 386
 387 static inline void skip_same_name(struct cache_entry *ce, struct unpack_trees_options *o)
 388 {
 389         int len = ce_namelen(ce);
 390         const struct index_state *index = o->src_index;
 391
 392         while (o->pos < index->cache_nr) {
 393                 struct cache_entry *next = index->cache[o->pos];
 394                 if (len != ce_namelen(next))
 395                         break;
 396                 if (memcmp(ce->name, next->name, len))
 397                         break;
 398                 o->pos++;
 399         }
 400 }
 401
 402 /*
 403  * The unpack_trees() interface is designed for merging, so
 404  * the different source entries are designed primarily for
 405  * the source trees, with the old index being really mainly
 406  * used for being replaced by the result.
 407  *
 408  * For diffing, the index is more important, and we only have a
 409  * single tree.
 410  *
 411  * We're supposed to return how many index entries we want to skip.
 412  *
 413  * This wrapper makes it all more readable, and takes care of all
 414  * the fairly complex unpack_trees() semantic requirements, including
 415  * the skipping, the path matching, the type conflict cases etc.
 416  */
 417 static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
 418 {
 419         struct cache_entry *idx = src[0];
 420         struct cache_entry *tree = src[1];
 421         struct oneway_unpack_data *cbdata = o->unpack_data;
 422         struct rev_info *revs = cbdata->revs;
 423
 424         if (idx && ce_stage(idx))
 425                 skip_same_name(idx, o);
 426
 427         /*
 428          * Unpack-trees generates a DF/conflict entry if
 429          * there was a directory in the index and a tree
 430          * in the tree. From a diff standpoint, that's a
 431          * delete of the tree and a create of the file.
 432          */
 433         if (tree == o->df_conflict_entry)
 434                 tree = NULL;
 435
 436         if (ce_path_match(idx ? idx : tree, revs->prune_data))
 437                 do_oneway_diff(o, idx, tree);
 438
 439         return 0;
 440 }
 441
 442 int run_diff_index(struct rev_info *revs, int cached)
 443 {
 444         struct object *ent;
 445         struct tree *tree;
 446         const char *tree_name;
 447         struct unpack_trees_options opts;
 448         struct tree_desc t;
 449         struct oneway_unpack_data unpack_cb;
 450
 451         mark_merge_entries();
 452
 453         ent = revs->pending.objects[0].item;
 454         tree_name = revs->pending.objects[0].name;
 455         tree = parse_tree_indirect(ent->sha1);
 456         if (!tree)
 457                 return error("bad tree object %s", tree_name);
 458
 459         unpack_cb.revs = revs;
 460         unpack_cb.symcache[0] = '\0';
 461         memset(&opts, 0, sizeof(opts));
 462         opts.head_idx = 1;
 463         opts.index_only = cached;
 464         opts.merge = 1;
 465         opts.fn = oneway_diff;
 466         opts.unpack_data = &unpack_cb;
 467         opts.src_index = &the_index;
 468         opts.dst_index = NULL;
 469
 470         init_tree_desc(&t, tree->buffer, tree->size);
 471         if (unpack_trees(1, &t, &opts))
 472                 exit(128);
 473
 474         diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
 475         diffcore_std(&revs->diffopt);
 476         diff_flush(&revs->diffopt);
 477         return 0;
 478 }
 479
 480 int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 481 {
 482         struct tree *tree;
 483         struct rev_info revs;
 484         int i;
 485         struct cache_entry **dst;
 486         struct cache_entry *last = NULL;
 487         struct unpack_trees_options opts;
 488         struct tree_desc t;
 489         struct oneway_unpack_data unpack_cb;
 490
 491         /*
 492          * This is used by git-blame to run diff-cache internally;
 493          * it potentially needs to repeatedly run this, so we will
 494          * start by removing the higher order entries the last round
 495          * left behind.
 496          */
 497         dst = active_cache;
 498         for (i = 0; i < active_nr; i++) {
 499                 struct cache_entry *ce = active_cache[i];
 500                 if (ce_stage(ce)) {
 501                         if (last && !strcmp(ce->name, last->name))
 502                                 continue;
 503                         cache_tree_invalidate_path(active_cache_tree,
 504                                                    ce->name);
 505                         last = ce;
 506                         ce->ce_flags |= CE_REMOVE;
 507                 }
 508                 *dst++ = ce;
 509         }
 510         active_nr = dst - active_cache;
 511
 512         init_revisions(&revs, NULL);
 513         revs.prune_data = opt->paths;
 514         tree = parse_tree_indirect(tree_sha1);
 515         if (!tree)
 516                 die("bad tree object %s", sha1_to_hex(tree_sha1));
 517
 518         unpack_cb.revs = &revs;
 519         unpack_cb.symcache[0] = '\0';
 520         memset(&opts, 0, sizeof(opts));
 521         opts.head_idx = 1;
 522         opts.index_only = 1;
 523         opts.merge = 1;
 524         opts.fn = oneway_diff;
 525         opts.unpack_data = &unpack_cb;
 526         opts.src_index = &the_index;
 527         opts.dst_index = &the_index;
 528
 529         init_tree_desc(&t, tree->buffer, tree->size);
 530         if (unpack_trees(1, &t, &opts))
 531                 exit(128);
 532         return 0;
 533 }