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