builtin/diff.c

   1 /*
   2  * Builtin "git diff"
   3  *
   4  * Copyright (c) 2006 Junio C Hamano
   5  */
   6 #define USE_THE_INDEX_COMPATIBILITY_MACROS
   7 #include "cache.h"
   8 #include "config.h"
   9 #include "ewah/ewok.h"
  10 #include "lockfile.h"
  11 #include "color.h"
  12 #include "commit.h"
  13 #include "blob.h"
  14 #include "tag.h"
  15 #include "diff.h"
  16 #include "diff-merges.h"
  17 #include "diffcore.h"
  18 #include "revision.h"
  19 #include "log-tree.h"
  20 #include "builtin.h"
  21 #include "submodule.h"
  22 #include "oid-array.h"
  23
  24 #define DIFF_NO_INDEX_EXPLICIT 1
  25 #define DIFF_NO_INDEX_IMPLICIT 2
  26
  27 static const char builtin_diff_usage[] =
  28 "git diff [<options>] [<commit>] [--] [<path>...]\n"
  29 "   or: git diff [<options>] --cached [<commit>] [--] [<path>...]\n"
  30 "   or: git diff [<options>] <commit> [--merge-base] [<commit>...] <commit> [--] [<path>...]\n"
  31 "   or: git diff [<options>] <commit>...<commit>] [--] [<path>...]\n"
  32 "   or: git diff [<options>] <blob> <blob>]\n"
  33 "   or: git diff [<options>] --no-index [--] <path> <path>]\n"
  34 COMMON_DIFF_OPTIONS_HELP;
  35
  36 static const char *blob_path(struct object_array_entry *entry)
  37 {
  38         return entry->path ? entry->path : entry->name;
  39 }
  40
  41 static void stuff_change(struct diff_options *opt,
  42                          unsigned old_mode, unsigned new_mode,
  43                          const struct object_id *old_oid,
  44                          const struct object_id *new_oid,
  45                          int old_oid_valid,
  46                          int new_oid_valid,
  47                          const char *old_path,
  48                          const char *new_path)
  49 {
  50         struct diff_filespec *one, *two;
  51
  52         if (!is_null_oid(old_oid) && !is_null_oid(new_oid) &&
  53             oideq(old_oid, new_oid) && (old_mode == new_mode))
  54                 return;
  55
  56         if (opt->flags.reverse_diff) {
  57                 SWAP(old_mode, new_mode);
  58                 SWAP(old_oid, new_oid);
  59                 SWAP(old_path, new_path);
  60         }
  61
  62         if (opt->prefix &&
  63             (strncmp(old_path, opt->prefix, opt->prefix_length) ||
  64              strncmp(new_path, opt->prefix, opt->prefix_length)))
  65                 return;
  66
  67         one = alloc_filespec(old_path);
  68         two = alloc_filespec(new_path);
  69         fill_filespec(one, old_oid, old_oid_valid, old_mode);
  70         fill_filespec(two, new_oid, new_oid_valid, new_mode);
  71
  72         diff_queue(&diff_queued_diff, one, two);
  73 }
  74
  75 static int builtin_diff_b_f(struct rev_info *revs,
  76                             int argc, const char **argv,
  77                             struct object_array_entry **blob)
  78 {
  79         /* Blob vs file in the working tree*/
  80         struct stat st;
  81         const char *path;
  82
  83         if (argc > 1)
  84                 usage(builtin_diff_usage);
  85
  86         GUARD_PATHSPEC(&revs->prune_data, PATHSPEC_FROMTOP | PATHSPEC_LITERAL);
  87         path = revs->prune_data.items[0].match;
  88
  89         if (lstat(path, &st))
  90                 die_errno(_("failed to stat '%s'"), path);
  91         if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
  92                 die(_("'%s': not a regular file or symlink"), path);
  93
  94         diff_set_mnemonic_prefix(&revs->diffopt, "o/", "w/");
  95
  96         if (blob[0]->mode == S_IFINVALID)
  97                 blob[0]->mode = canon_mode(st.st_mode);
  98
  99         stuff_change(&revs->diffopt,
 100                      blob[0]->mode, canon_mode(st.st_mode),
 101                      &blob[0]->item->oid, &null_oid,
 102                      1, 0,
 103                      blob[0]->path ? blob[0]->path : path,
 104                      path);
 105         diffcore_std(&revs->diffopt);
 106         diff_flush(&revs->diffopt);
 107         return 0;
 108 }
 109
 110 static int builtin_diff_blobs(struct rev_info *revs,
 111                               int argc, const char **argv,
 112                               struct object_array_entry **blob)
 113 {
 114         const unsigned mode = canon_mode(S_IFREG | 0644);
 115
 116         if (argc > 1)
 117                 usage(builtin_diff_usage);
 118
 119         if (blob[0]->mode == S_IFINVALID)
 120                 blob[0]->mode = mode;
 121
 122         if (blob[1]->mode == S_IFINVALID)
 123                 blob[1]->mode = mode;
 124
 125         stuff_change(&revs->diffopt,
 126                      blob[0]->mode, blob[1]->mode,
 127                      &blob[0]->item->oid, &blob[1]->item->oid,
 128                      1, 1,
 129                      blob_path(blob[0]), blob_path(blob[1]));
 130         diffcore_std(&revs->diffopt);
 131         diff_flush(&revs->diffopt);
 132         return 0;
 133 }
 134
 135 static int builtin_diff_index(struct rev_info *revs,
 136                               int argc, const char **argv)
 137 {
 138         unsigned int option = 0;
 139         while (1 < argc) {
 140                 const char *arg = argv[1];
 141                 if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
 142                         option |= DIFF_INDEX_CACHED;
 143                 else if (!strcmp(arg, "--merge-base"))
 144                         option |= DIFF_INDEX_MERGE_BASE;
 145                 else
 146                         usage(builtin_diff_usage);
 147                 argv++; argc--;
 148         }
 149         /*
 150          * Make sure there is one revision (i.e. pending object),
 151          * and there is no revision filtering parameters.
 152          */
 153         if (revs->pending.nr != 1 ||
 154             revs->max_count != -1 || revs->min_age != -1 ||
 155             revs->max_age != -1)
 156                 usage(builtin_diff_usage);
 157         if (!(option & DIFF_INDEX_CACHED)) {
 158                 setup_work_tree();
 159                 if (read_cache_preload(&revs->diffopt.pathspec) < 0) {
 160                         perror("read_cache_preload");
 161                         return -1;
 162                 }
 163         } else if (read_cache() < 0) {
 164                 perror("read_cache");
 165                 return -1;
 166         }
 167         return run_diff_index(revs, option);
 168 }
 169
 170 static int builtin_diff_tree(struct rev_info *revs,
 171                              int argc, const char **argv,
 172                              struct object_array_entry *ent0,
 173                              struct object_array_entry *ent1)
 174 {
 175         const struct object_id *(oid[2]);
 176         struct object_id mb_oid;
 177         int merge_base = 0;
 178
 179         while (1 < argc) {
 180                 const char *arg = argv[1];
 181                 if (!strcmp(arg, "--merge-base"))
 182                         merge_base = 1;
 183                 else
 184                         usage(builtin_diff_usage);
 185                 argv++; argc--;
 186         }
 187
 188         if (merge_base) {
 189                 diff_get_merge_base(revs, &mb_oid);
 190                 oid[0] = &mb_oid;
 191                 oid[1] = &revs->pending.objects[1].item->oid;
 192         } else {
 193                 int swap = 0;
 194
 195                 /*
 196                  * We saw two trees, ent0 and ent1.  If ent1 is uninteresting,
 197                  * swap them.
 198                  */
 199                 if (ent1->item->flags & UNINTERESTING)
 200                         swap = 1;
 201                 oid[swap] = &ent0->item->oid;
 202                 oid[1 - swap] = &ent1->item->oid;
 203         }
 204         diff_tree_oid(oid[0], oid[1], "", &revs->diffopt);
 205         log_tree_diff_flush(revs);
 206         return 0;
 207 }
 208
 209 static int builtin_diff_combined(struct rev_info *revs,
 210                                  int argc, const char **argv,
 211                                  struct object_array_entry *ent,
 212                                  int ents)
 213 {
 214         struct oid_array parents = OID_ARRAY_INIT;
 215         int i;
 216
 217         if (argc > 1)
 218                 usage(builtin_diff_usage);
 219
 220         diff_merges_set_dense_combined_if_unset(revs);
 221
 222         for (i = 1; i < ents; i++)
 223                 oid_array_append(&parents, &ent[i].item->oid);
 224         diff_tree_combined(&ent[0].item->oid, &parents, revs);
 225         oid_array_clear(&parents);
 226         return 0;
 227 }
 228
 229 static void refresh_index_quietly(void)
 230 {
 231         struct lock_file lock_file = LOCK_INIT;
 232         int fd;
 233
 234         fd = hold_locked_index(&lock_file, 0);
 235         if (fd < 0)
 236                 return;
 237         discard_cache();
 238         read_cache();
 239         refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
 240         repo_update_index_if_able(the_repository, &lock_file);
 241 }
 242
 243 static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
 244 {
 245         unsigned int options = 0;
 246
 247         while (1 < argc && argv[1][0] == '-') {
 248                 if (!strcmp(argv[1], "--base"))
 249                         revs->max_count = 1;
 250                 else if (!strcmp(argv[1], "--ours"))
 251                         revs->max_count = 2;
 252                 else if (!strcmp(argv[1], "--theirs"))
 253                         revs->max_count = 3;
 254                 else if (!strcmp(argv[1], "-q"))
 255                         options |= DIFF_SILENT_ON_REMOVED;
 256                 else if (!strcmp(argv[1], "-h"))
 257                         usage(builtin_diff_usage);
 258                 else
 259                         return error(_("invalid option: %s"), argv[1]);
 260                 argv++; argc--;
 261         }
 262
 263         /*
 264          * "diff --base" should not combine merges because it was not
 265          * asked to.  "diff -c" should not densify (if the user wants
 266          * dense one, --cc can be explicitly asked for, or just rely
 267          * on the default).
 268          */
 269         if (revs->max_count == -1 &&
 270             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
 271                 diff_merges_set_dense_combined_if_unset(revs);
 272
 273         setup_work_tree();
 274         if (read_cache_preload(&revs->diffopt.pathspec) < 0) {
 275                 perror("read_cache_preload");
 276                 return -1;
 277         }
 278         return run_diff_files(revs, options);
 279 }
 280
 281 struct symdiff {
 282         struct bitmap *skip;
 283         int warn;
 284         const char *base, *left, *right;
 285 };
 286
 287 /*
 288  * Check for symmetric-difference arguments, and if present, arrange
 289  * everything we need to know to handle them correctly.  As a bonus,
 290  * weed out all bogus range-based revision specifications, e.g.,
 291  * "git diff A..B C..D" or "git diff A..B C" get rejected.
 292  *
 293  * For an actual symmetric diff, *symdiff is set this way:
 294  *
 295  *  - its skip is non-NULL and marks *all* rev->pending.objects[i]
 296  *    indices that the caller should ignore (extra merge bases, of
 297  *    which there might be many, and A in A...B).  Note that the
 298  *    chosen merge base and right side are NOT marked.
 299  *  - warn is set if there are multiple merge bases.
 300  *  - base, left, and right point to the names to use in a
 301  *    warning about multiple merge bases.
 302  *
 303  * If there is no symmetric diff argument, sym->skip is NULL and
 304  * sym->warn is cleared.  The remaining fields are not set.
 305  */
 306 static void symdiff_prepare(struct rev_info *rev, struct symdiff *sym)
 307 {
 308         int i, is_symdiff = 0, basecount = 0, othercount = 0;
 309         int lpos = -1, rpos = -1, basepos = -1;
 310         struct bitmap *map = NULL;
 311
 312         /*
 313          * Use the whence fields to find merge bases and left and
 314          * right parts of symmetric difference, so that we do not
 315          * depend on the order that revisions are parsed.  If there
 316          * are any revs that aren't from these sources, we have a
 317          * "git diff C A...B" or "git diff A...B C" case.  Or we
 318          * could even get "git diff A...B C...E", for instance.
 319          *
 320          * If we don't have just one merge base, we pick one
 321          * at random.
 322          *
 323          * NB: REV_CMD_LEFT, REV_CMD_RIGHT are also used for A..B,
 324          * so we must check for SYMMETRIC_LEFT too.  The two arrays
 325          * rev->pending.objects and rev->cmdline.rev are parallel.
 326          */
 327         for (i = 0; i < rev->cmdline.nr; i++) {
 328                 struct object *obj = rev->pending.objects[i].item;
 329                 switch (rev->cmdline.rev[i].whence) {
 330                 case REV_CMD_MERGE_BASE:
 331                         if (basepos < 0)
 332                                 basepos = i;
 333                         basecount++;
 334                         break;          /* do mark all bases */
 335                 case REV_CMD_LEFT:
 336                         if (lpos >= 0)
 337                                 usage(builtin_diff_usage);
 338                         lpos = i;
 339                         if (obj->flags & SYMMETRIC_LEFT) {
 340                                 is_symdiff = 1;
 341                                 break;  /* do mark A */
 342                         }
 343                         continue;
 344                 case REV_CMD_RIGHT:
 345                         if (rpos >= 0)
 346                                 usage(builtin_diff_usage);
 347                         rpos = i;
 348                         continue;       /* don't mark B */
 349                 case REV_CMD_PARENTS_ONLY:
 350                 case REV_CMD_REF:
 351                 case REV_CMD_REV:
 352                         othercount++;
 353                         continue;
 354                 }
 355                 if (map == NULL)
 356                         map = bitmap_new();
 357                 bitmap_set(map, i);
 358         }
 359
 360         /*
 361          * Forbid any additional revs for both A...B and A..B.
 362          */
 363         if (lpos >= 0 && othercount > 0)
 364                 usage(builtin_diff_usage);
 365
 366         if (!is_symdiff) {
 367                 bitmap_free(map);
 368                 sym->warn = 0;
 369                 sym->skip = NULL;
 370                 return;
 371         }
 372
 373         sym->left = rev->pending.objects[lpos].name;
 374         sym->right = rev->pending.objects[rpos].name;
 375         if (basecount == 0)
 376                 die(_("%s...%s: no merge base"), sym->left, sym->right);
 377         sym->base = rev->pending.objects[basepos].name;
 378         bitmap_unset(map, basepos);     /* unmark the base we want */
 379         sym->warn = basecount > 1;
 380         sym->skip = map;
 381 }
 382
 383 int cmd_diff(int argc, const char **argv, const char *prefix)
 384 {
 385         int i;
 386         struct rev_info rev;
 387         struct object_array ent = OBJECT_ARRAY_INIT;
 388         int blobs = 0, paths = 0;
 389         struct object_array_entry *blob[2];
 390         int nongit = 0, no_index = 0;
 391         int result = 0;
 392         struct symdiff sdiff;
 393
 394         /*
 395          * We could get N tree-ish in the rev.pending_objects list.
 396          * Also there could be M blobs there, and P pathspecs. --cached may
 397          * also be present.
 398          *
 399          * N=0, M=0:
 400          *      cache vs files (diff-files)
 401          *
 402          * N=0, M=0, --cached:
 403          *      HEAD vs cache (diff-index --cached)
 404          *
 405          * N=0, M=2:
 406          *      compare two random blobs.  P must be zero.
 407          *
 408          * N=0, M=1, P=1:
 409          *      compare a blob with a working tree file.
 410          *
 411          * N=1, M=0:
 412          *      tree vs files (diff-index)
 413          *
 414          * N=1, M=0, --cached:
 415          *      tree vs cache (diff-index --cached)
 416          *
 417          * N=2, M=0:
 418          *      tree vs tree (diff-tree)
 419          *
 420          * N=0, M=0, P=2:
 421          *      compare two filesystem entities (aka --no-index).
 422          *
 423          * Other cases are errors.
 424          */
 425
 426         /* Were we asked to do --no-index explicitly? */
 427         for (i = 1; i < argc; i++) {
 428                 if (!strcmp(argv[i], "--")) {
 429                         i++;
 430                         break;
 431                 }
 432                 if (!strcmp(argv[i], "--no-index"))
 433                         no_index = DIFF_NO_INDEX_EXPLICIT;
 434                 if (argv[i][0] != '-')
 435                         break;
 436         }
 437
 438         prefix = setup_git_directory_gently(&nongit);
 439
 440         if (!no_index) {
 441                 /*
 442                  * Treat git diff with at least one path outside of the
 443                  * repo the same as if the command would have been executed
 444                  * outside of a git repository.  In this case it behaves
 445                  * the same way as "git diff --no-index <a> <b>", which acts
 446                  * as a colourful "diff" replacement.
 447                  */
 448                 if (nongit || ((argc == i + 2) &&
 449                                (!path_inside_repo(prefix, argv[i]) ||
 450                                 !path_inside_repo(prefix, argv[i + 1]))))
 451                         no_index = DIFF_NO_INDEX_IMPLICIT;
 452         }
 453
 454         init_diff_ui_defaults();
 455         git_config(git_diff_ui_config, NULL);
 456         prefix = precompose_argv_prefix(argc, argv, prefix);
 457
 458         repo_init_revisions(the_repository, &rev, prefix);
 459
 460         /* Set up defaults that will apply to both no-index and regular diffs. */
 461         rev.diffopt.stat_width = -1;
 462         rev.diffopt.stat_graph_width = -1;
 463         rev.diffopt.flags.allow_external = 1;
 464         rev.diffopt.flags.allow_textconv = 1;
 465
 466         /* If this is a no-index diff, just run it and exit there. */
 467         if (no_index)
 468                 exit(diff_no_index(&rev, no_index == DIFF_NO_INDEX_IMPLICIT,
 469                                    argc, argv));
 470
 471
 472         /*
 473          * Otherwise, we are doing the usual "git" diff; set up any
 474          * further defaults that apply to regular diffs.
 475          */
 476         rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 477
 478         /*
 479          * Default to intent-to-add entries invisible in the
 480          * index. This makes them show up as new files in diff-files
 481          * and not at all in diff-cached.
 482          */
 483         rev.diffopt.ita_invisible_in_index = 1;
 484
 485         if (nongit)
 486                 die(_("Not a git repository"));
 487         argc = setup_revisions(argc, argv, &rev, NULL);
 488         if (!rev.diffopt.output_format) {
 489                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
 490                 diff_setup_done(&rev.diffopt);
 491         }
 492
 493         rev.diffopt.flags.recursive = 1;
 494         rev.diffopt.rotate_to_strict = 1;
 495
 496         setup_diff_pager(&rev.diffopt);
 497
 498         /*
 499          * Do we have --cached and not have a pending object, then
 500          * default to HEAD by hand.  Eek.
 501          */
 502         if (!rev.pending.nr) {
 503                 int i;
 504                 for (i = 1; i < argc; i++) {
 505                         const char *arg = argv[i];
 506                         if (!strcmp(arg, "--"))
 507                                 break;
 508                         else if (!strcmp(arg, "--cached") ||
 509                                  !strcmp(arg, "--staged")) {
 510                                 add_head_to_pending(&rev);
 511                                 if (!rev.pending.nr) {
 512                                         struct tree *tree;
 513                                         tree = lookup_tree(the_repository,
 514                                                            the_repository->hash_algo->empty_tree);
 515                                         add_pending_object(&rev, &tree->object, "HEAD");
 516                                 }
 517                                 break;
 518                         }
 519                 }
 520         }
 521
 522         symdiff_prepare(&rev, &sdiff);
 523         for (i = 0; i < rev.pending.nr; i++) {
 524                 struct object_array_entry *entry = &rev.pending.objects[i];
 525                 struct object *obj = entry->item;
 526                 const char *name = entry->name;
 527                 int flags = (obj->flags & UNINTERESTING);
 528                 if (!obj->parsed)
 529                         obj = parse_object(the_repository, &obj->oid);
 530                 obj = deref_tag(the_repository, obj, NULL, 0);
 531                 if (!obj)
 532                         die(_("invalid object '%s' given."), name);
 533                 if (obj->type == OBJ_COMMIT)
 534                         obj = &get_commit_tree(((struct commit *)obj))->object;
 535
 536                 if (obj->type == OBJ_TREE) {
 537                         if (sdiff.skip && bitmap_get(sdiff.skip, i))
 538                                 continue;
 539                         obj->flags |= flags;
 540                         add_object_array(obj, name, &ent);
 541                 } else if (obj->type == OBJ_BLOB) {
 542                         if (2 <= blobs)
 543                                 die(_("more than two blobs given: '%s'"), name);
 544                         blob[blobs] = entry;
 545                         blobs++;
 546
 547                 } else {
 548                         die(_("unhandled object '%s' given."), name);
 549                 }
 550         }
 551         if (rev.prune_data.nr)
 552                 paths += rev.prune_data.nr;
 553
 554         /*
 555          * Now, do the arguments look reasonable?
 556          */
 557         if (!ent.nr) {
 558                 switch (blobs) {
 559                 case 0:
 560                         result = builtin_diff_files(&rev, argc, argv);
 561                         break;
 562                 case 1:
 563                         if (paths != 1)
 564                                 usage(builtin_diff_usage);
 565                         result = builtin_diff_b_f(&rev, argc, argv, blob);
 566                         break;
 567                 case 2:
 568                         if (paths)
 569                                 usage(builtin_diff_usage);
 570                         result = builtin_diff_blobs(&rev, argc, argv, blob);
 571                         break;
 572                 default:
 573                         usage(builtin_diff_usage);
 574                 }
 575         }
 576         else if (blobs)
 577                 usage(builtin_diff_usage);
 578         else if (ent.nr == 1)
 579                 result = builtin_diff_index(&rev, argc, argv);
 580         else if (ent.nr == 2) {
 581                 if (sdiff.warn)
 582                         warning(_("%s...%s: multiple merge bases, using %s"),
 583                                 sdiff.left, sdiff.right, sdiff.base);
 584                 result = builtin_diff_tree(&rev, argc, argv,
 585                                            &ent.objects[0], &ent.objects[1]);
 586         } else
 587                 result = builtin_diff_combined(&rev, argc, argv,
 588                                                ent.objects, ent.nr);
 589         result = diff_result_code(&rev.diffopt, result);
 590         if (1 < rev.diffopt.skip_stat_unmatch)
 591                 refresh_index_quietly();
 592         UNLEAK(rev);
 593         UNLEAK(ent);
 594         UNLEAK(blob);
 595         return result;
 596 }