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