builtin/diff.c

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