builtin/diff.c

   1 /*
   2  * Builtin "git diff"
   3  *
   4  * Copyright (c) 2006 Junio C Hamano
   5  */
   6 #include "cache.h"
   7 #include "lockfile.h"
   8 #include "color.h"
   9 #include "commit.h"
  10 #include "blob.h"
  11 #include "tag.h"
  12 #include "diff.h"
  13 #include "diffcore.h"
  14 #include "revision.h"
  15 #include "log-tree.h"
  16 #include "builtin.h"
  17 #include "submodule.h"
  18 #include "sha1-array.h"
  19
  20 #define DIFF_NO_INDEX_EXPLICIT 1
  21 #define DIFF_NO_INDEX_IMPLICIT 2
  22
  23 struct blobinfo {
  24         unsigned char sha1[20];
  25         const char *name;
  26         unsigned mode;
  27 };
  28
  29 static const char builtin_diff_usage[] =
  30 "git diff [<options>] [<commit> [<commit>]] [--] [<path>...]";
  31
  32 static void stuff_change(struct diff_options *opt,
  33                          unsigned old_mode, unsigned new_mode,
  34                          const unsigned char *old_sha1,
  35                          const unsigned char *new_sha1,
  36                          int old_sha1_valid,
  37                          int new_sha1_valid,
  38                          const char *old_name,
  39                          const char *new_name)
  40 {
  41         struct diff_filespec *one, *two;
  42
  43         if (!is_null_sha1(old_sha1) && !is_null_sha1(new_sha1) &&
  44             !hashcmp(old_sha1, new_sha1) && (old_mode == new_mode))
  45                 return;
  46
  47         if (DIFF_OPT_TST(opt, REVERSE_DIFF)) {
  48                 unsigned tmp;
  49                 const unsigned char *tmp_u;
  50                 const char *tmp_c;
  51                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
  52                 tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
  53                 tmp_c = old_name; old_name = new_name; new_name = tmp_c;
  54         }
  55
  56         if (opt->prefix &&
  57             (strncmp(old_name, opt->prefix, opt->prefix_length) ||
  58              strncmp(new_name, opt->prefix, opt->prefix_length)))
  59                 return;
  60
  61         one = alloc_filespec(old_name);
  62         two = alloc_filespec(new_name);
  63         fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
  64         fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
  65
  66         diff_queue(&diff_queued_diff, one, two);
  67 }
  68
  69 static int builtin_diff_b_f(struct rev_info *revs,
  70                             int argc, const char **argv,
  71                             struct blobinfo *blob)
  72 {
  73         /* Blob vs file in the working tree*/
  74         struct stat st;
  75         const char *path;
  76
  77         if (argc > 1)
  78                 usage(builtin_diff_usage);
  79
  80         GUARD_PATHSPEC(&revs->prune_data, PATHSPEC_FROMTOP | PATHSPEC_LITERAL);
  81         path = revs->prune_data.items[0].match;
  82
  83         if (lstat(path, &st))
  84                 die_errno(_("failed to stat '%s'"), path);
  85         if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
  86                 die(_("'%s': not a regular file or symlink"), path);
  87
  88         diff_set_mnemonic_prefix(&revs->diffopt, "o/", "w/");
  89
  90         if (blob[0].mode == S_IFINVALID)
  91                 blob[0].mode = canon_mode(st.st_mode);
  92
  93         stuff_change(&revs->diffopt,
  94                      blob[0].mode, canon_mode(st.st_mode),
  95                      blob[0].sha1, null_sha1,
  96                      1, 0,
  97                      path, path);
  98         diffcore_std(&revs->diffopt);
  99         diff_flush(&revs->diffopt);
 100         return 0;
 101 }
 102
 103 static int builtin_diff_blobs(struct rev_info *revs,
 104                               int argc, const char **argv,
 105                               struct blobinfo *blob)
 106 {
 107         unsigned mode = canon_mode(S_IFREG | 0644);
 108
 109         if (argc > 1)
 110                 usage(builtin_diff_usage);
 111
 112         if (blob[0].mode == S_IFINVALID)
 113                 blob[0].mode = mode;
 114
 115         if (blob[1].mode == S_IFINVALID)
 116                 blob[1].mode = mode;
 117
 118         stuff_change(&revs->diffopt,
 119                      blob[0].mode, blob[1].mode,
 120                      blob[0].sha1, blob[1].sha1,
 121                      1, 1,
 122                      blob[0].name, blob[1].name);
 123         diffcore_std(&revs->diffopt);
 124         diff_flush(&revs->diffopt);
 125         return 0;
 126 }
 127
 128 static int builtin_diff_index(struct rev_info *revs,
 129                               int argc, const char **argv)
 130 {
 131         int cached = 0;
 132         while (1 < argc) {
 133                 const char *arg = argv[1];
 134                 if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
 135                         cached = 1;
 136                 else
 137                         usage(builtin_diff_usage);
 138                 argv++; argc--;
 139         }
 140         /*
 141          * Make sure there is one revision (i.e. pending object),
 142          * and there is no revision filtering parameters.
 143          */
 144         if (revs->pending.nr != 1 ||
 145             revs->max_count != -1 || revs->min_age != -1 ||
 146             revs->max_age != -1)
 147                 usage(builtin_diff_usage);
 148         if (!cached) {
 149                 setup_work_tree();
 150                 if (read_cache_preload(&revs->diffopt.pathspec) < 0) {
 151                         perror("read_cache_preload");
 152                         return -1;
 153                 }
 154         } else if (read_cache() < 0) {
 155                 perror("read_cache");
 156                 return -1;
 157         }
 158         return run_diff_index(revs, cached);
 159 }
 160
 161 static int builtin_diff_tree(struct rev_info *revs,
 162                              int argc, const char **argv,
 163                              struct object_array_entry *ent0,
 164                              struct object_array_entry *ent1)
 165 {
 166         const unsigned char *(sha1[2]);
 167         int swap = 0;
 168
 169         if (argc > 1)
 170                 usage(builtin_diff_usage);
 171
 172         /*
 173          * We saw two trees, ent0 and ent1.  If ent1 is uninteresting,
 174          * swap them.
 175          */
 176         if (ent1->item->flags & UNINTERESTING)
 177                 swap = 1;
 178         sha1[swap] = ent0->item->sha1;
 179         sha1[1 - swap] = ent1->item->sha1;
 180         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
 181         log_tree_diff_flush(revs);
 182         return 0;
 183 }
 184
 185 static int builtin_diff_combined(struct rev_info *revs,
 186                                  int argc, const char **argv,
 187                                  struct object_array_entry *ent,
 188                                  int ents)
 189 {
 190         struct sha1_array parents = SHA1_ARRAY_INIT;
 191         int i;
 192
 193         if (argc > 1)
 194                 usage(builtin_diff_usage);
 195
 196         if (!revs->dense_combined_merges && !revs->combine_merges)
 197                 revs->dense_combined_merges = revs->combine_merges = 1;
 198         for (i = 1; i < ents; i++)
 199                 sha1_array_append(&parents, ent[i].item->sha1);
 200         diff_tree_combined(ent[0].item->sha1, &parents,
 201                            revs->dense_combined_merges, revs);
 202         sha1_array_clear(&parents);
 203         return 0;
 204 }
 205
 206 static void refresh_index_quietly(void)
 207 {
 208         struct lock_file *lock_file;
 209         int fd;
 210
 211         lock_file = xcalloc(1, sizeof(struct lock_file));
 212         fd = hold_locked_index(lock_file, 0);
 213         if (fd < 0)
 214                 return;
 215         discard_cache();
 216         read_cache();
 217         refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
 218         update_index_if_able(&the_index, lock_file);
 219 }
 220
 221 static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
 222 {
 223         unsigned int options = 0;
 224
 225         while (1 < argc && argv[1][0] == '-') {
 226                 if (!strcmp(argv[1], "--base"))
 227                         revs->max_count = 1;
 228                 else if (!strcmp(argv[1], "--ours"))
 229                         revs->max_count = 2;
 230                 else if (!strcmp(argv[1], "--theirs"))
 231                         revs->max_count = 3;
 232                 else if (!strcmp(argv[1], "-q"))
 233                         options |= DIFF_SILENT_ON_REMOVED;
 234                 else if (!strcmp(argv[1], "-h"))
 235                         usage(builtin_diff_usage);
 236                 else
 237                         return error(_("invalid option: %s"), argv[1]);
 238                 argv++; argc--;
 239         }
 240
 241         /*
 242          * "diff --base" should not combine merges because it was not
 243          * asked to.  "diff -c" should not densify (if the user wants
 244          * dense one, --cc can be explicitly asked for, or just rely
 245          * on the default).
 246          */
 247         if (revs->max_count == -1 && !revs->combine_merges &&
 248             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
 249                 revs->combine_merges = revs->dense_combined_merges = 1;
 250
 251         setup_work_tree();
 252         if (read_cache_preload(&revs->diffopt.pathspec) < 0) {
 253                 perror("read_cache_preload");
 254                 return -1;
 255         }
 256         return run_diff_files(revs, options);
 257 }
 258
 259 int cmd_diff(int argc, const char **argv, const char *prefix)
 260 {
 261         int i;
 262         struct rev_info rev;
 263         struct object_array ent = OBJECT_ARRAY_INIT;
 264         int blobs = 0, paths = 0;
 265         struct blobinfo blob[2];
 266         int nongit = 0, no_index = 0;
 267         int result = 0;
 268
 269         /*
 270          * We could get N tree-ish in the rev.pending_objects list.
 271          * Also there could be M blobs there, and P pathspecs.
 272          *
 273          * N=0, M=0:
 274          *      cache vs files (diff-files)
 275          * N=0, M=2:
 276          *      compare two random blobs.  P must be zero.
 277          * N=0, M=1, P=1:
 278          *      compare a blob with a working tree file.
 279          *
 280          * N=1, M=0:
 281          *      tree vs cache (diff-index --cached)
 282          *
 283          * N=2, M=0:
 284          *      tree vs tree (diff-tree)
 285          *
 286          * N=0, M=0, P=2:
 287          *      compare two filesystem entities (aka --no-index).
 288          *
 289          * Other cases are errors.
 290          */
 291
 292         /* Were we asked to do --no-index explicitly? */
 293         for (i = 1; i < argc; i++) {
 294                 if (!strcmp(argv[i], "--")) {
 295                         i++;
 296                         break;
 297                 }
 298                 if (!strcmp(argv[i], "--no-index"))
 299                         no_index = DIFF_NO_INDEX_EXPLICIT;
 300                 if (argv[i][0] != '-')
 301                         break;
 302         }
 303
 304         if (!no_index)
 305                 prefix = setup_git_directory_gently(&nongit);
 306
 307         /*
 308          * Treat git diff with at least one path outside of the
 309          * repo the same as if the command would have been executed
 310          * outside of a git repository.  In this case it behaves
 311          * the same way as "git diff --no-index <a> <b>", which acts
 312          * as a colourful "diff" replacement.
 313          */
 314         if (nongit || ((argc == i + 2) &&
 315                        (!path_inside_repo(prefix, argv[i]) ||
 316                         !path_inside_repo(prefix, argv[i + 1]))))
 317                 no_index = DIFF_NO_INDEX_IMPLICIT;
 318
 319         if (!no_index)
 320                 gitmodules_config();
 321         git_config(git_diff_ui_config, NULL);
 322
 323         init_revisions(&rev, prefix);
 324
 325         if (no_index && argc != i + 2) {
 326                 if (no_index == DIFF_NO_INDEX_IMPLICIT) {
 327                         /*
 328                          * There was no --no-index and there were not two
 329                          * paths. It is possible that the user intended
 330                          * to do an inside-repository operation.
 331                          */
 332                         fprintf(stderr, "Not a git repository\n");
 333                         fprintf(stderr,
 334                                 "To compare two paths outside a working tree:\n");
 335                 }
 336                 /* Give the usage message for non-repository usage and exit. */
 337                 usagef("git diff %s <path> <path>",
 338                        no_index == DIFF_NO_INDEX_EXPLICIT ?
 339                        "--no-index" : "[--no-index]");
 340
 341         }
 342         if (no_index)
 343                 /* If this is a no-index diff, just run it and exit there. */
 344                 diff_no_index(&rev, argc, argv, prefix);
 345
 346         /* Otherwise, we are doing the usual "git" diff */
 347         rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 348
 349         /* Scale to real terminal size and respect statGraphWidth config */
 350         rev.diffopt.stat_width = -1;
 351         rev.diffopt.stat_graph_width = -1;
 352
 353         /* Default to let external and textconv be used */
 354         DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
 355         DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
 356
 357         if (nongit)
 358                 die(_("Not a git repository"));
 359         argc = setup_revisions(argc, argv, &rev, NULL);
 360         if (!rev.diffopt.output_format) {
 361                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
 362                 diff_setup_done(&rev.diffopt);
 363         }
 364
 365         DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
 366
 367         setup_diff_pager(&rev.diffopt);
 368
 369         /*
 370          * Do we have --cached and not have a pending object, then
 371          * default to HEAD by hand.  Eek.
 372          */
 373         if (!rev.pending.nr) {
 374                 int i;
 375                 for (i = 1; i < argc; i++) {
 376                         const char *arg = argv[i];
 377                         if (!strcmp(arg, "--"))
 378                                 break;
 379                         else if (!strcmp(arg, "--cached") ||
 380                                  !strcmp(arg, "--staged")) {
 381                                 add_head_to_pending(&rev);
 382                                 if (!rev.pending.nr) {
 383                                         struct tree *tree;
 384                                         tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
 385                                         add_pending_object(&rev, &tree->object, "HEAD");
 386                                 }
 387                                 break;
 388                         }
 389                 }
 390         }
 391
 392         for (i = 0; i < rev.pending.nr; i++) {
 393                 struct object_array_entry *entry = &rev.pending.objects[i];
 394                 struct object *obj = entry->item;
 395                 const char *name = entry->name;
 396                 int flags = (obj->flags & UNINTERESTING);
 397                 if (!obj->parsed)
 398                         obj = parse_object(obj->sha1);
 399                 obj = deref_tag(obj, NULL, 0);
 400                 if (!obj)
 401                         die(_("invalid object '%s' given."), name);
 402                 if (obj->type == OBJ_COMMIT)
 403                         obj = &((struct commit *)obj)->tree->object;
 404
 405                 if (obj->type == OBJ_TREE) {
 406                         obj->flags |= flags;
 407                         add_object_array(obj, name, &ent);
 408                 } else if (obj->type == OBJ_BLOB) {
 409                         if (2 <= blobs)
 410                                 die(_("more than two blobs given: '%s'"), name);
 411                         hashcpy(blob[blobs].sha1, obj->sha1);
 412                         blob[blobs].name = name;
 413                         blob[blobs].mode = entry->mode;
 414                         blobs++;
 415
 416                 } else {
 417                         die(_("unhandled object '%s' given."), name);
 418                 }
 419         }
 420         if (rev.prune_data.nr)
 421                 paths += rev.prune_data.nr;
 422
 423         /*
 424          * Now, do the arguments look reasonable?
 425          */
 426         if (!ent.nr) {
 427                 switch (blobs) {
 428                 case 0:
 429                         result = builtin_diff_files(&rev, argc, argv);
 430                         break;
 431                 case 1:
 432                         if (paths != 1)
 433                                 usage(builtin_diff_usage);
 434                         result = builtin_diff_b_f(&rev, argc, argv, blob);
 435                         break;
 436                 case 2:
 437                         if (paths)
 438                                 usage(builtin_diff_usage);
 439                         result = builtin_diff_blobs(&rev, argc, argv, blob);
 440                         break;
 441                 default:
 442                         usage(builtin_diff_usage);
 443                 }
 444         }
 445         else if (blobs)
 446                 usage(builtin_diff_usage);
 447         else if (ent.nr == 1)
 448                 result = builtin_diff_index(&rev, argc, argv);
 449         else if (ent.nr == 2)
 450                 result = builtin_diff_tree(&rev, argc, argv,
 451                                            &ent.objects[0], &ent.objects[1]);
 452         else if (ent.objects[0].item->flags & UNINTERESTING) {
 453                 /*
 454                  * diff A...B where there is at least one merge base
 455                  * between A and B.  We have ent.objects[0] ==
 456                  * merge-base, ent.objects[ents-2] == A, and
 457                  * ent.objects[ents-1] == B.  Show diff between the
 458                  * base and B.  Note that we pick one merge base at
 459                  * random if there are more than one.
 460                  */
 461                 result = builtin_diff_tree(&rev, argc, argv,
 462                                            &ent.objects[0],
 463                                            &ent.objects[ent.nr-1]);
 464         } else
 465                 result = builtin_diff_combined(&rev, argc, argv,
 466                                                ent.objects, ent.nr);
 467         result = diff_result_code(&rev.diffopt, result);
 468         if (1 < rev.diffopt.skip_stat_unmatch)
 469                 refresh_index_quietly();
 470         return result;
 471 }