builtin-diff.c

   1 /*
   2  * Builtin "git diff"
   3  *
   4  * Copyright (c) 2006 Junio C Hamano
   5  */
   6 #include "cache.h"
   7 #include "commit.h"
   8 #include "blob.h"
   9 #include "tag.h"
  10 #include "diff.h"
  11 #include "diffcore.h"
  12 #include "revision.h"
  13 #include "log-tree.h"
  14 #include "builtin.h"
  15
  16 /* NEEDSWORK: struct object has place for name but we _do_
  17  * know mode when we extracted the blob out of a tree, which
  18  * we currently lose.
  19  */
  20 struct blobinfo {
  21         unsigned char sha1[20];
  22         const char *name;
  23 };
  24
  25 static const char builtin_diff_usage[] =
  26 "git-diff <options> <rev>{0,2} -- <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))
  39                 return;
  40
  41         if (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         one = alloc_filespec(old_name);
  50         two = alloc_filespec(new_name);
  51         fill_filespec(one, old_sha1, old_mode);
  52         fill_filespec(two, new_sha1, new_mode);
  53
  54         /* NEEDSWORK: shouldn't this part of diffopt??? */
  55         diff_queue(&diff_queued_diff, one, two);
  56 }
  57
  58 static int builtin_diff_b_f(struct rev_info *revs,
  59                             int argc, const char **argv,
  60                             struct blobinfo *blob,
  61                             const char *path)
  62 {
  63         /* Blob vs file in the working tree*/
  64         struct stat st;
  65
  66         if (argc > 1)
  67                 usage(builtin_diff_usage);
  68
  69         if (lstat(path, &st))
  70                 die("'%s': %s", path, strerror(errno));
  71         if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
  72                 die("'%s': not a regular file or symlink", path);
  73         stuff_change(&revs->diffopt,
  74                      canon_mode(st.st_mode), canon_mode(st.st_mode),
  75                      blob[0].sha1, null_sha1,
  76                      path, path);
  77         diffcore_std(&revs->diffopt);
  78         diff_flush(&revs->diffopt);
  79         return 0;
  80 }
  81
  82 static int builtin_diff_blobs(struct rev_info *revs,
  83                               int argc, const char **argv,
  84                               struct blobinfo *blob)
  85 {
  86         unsigned mode = canon_mode(S_IFREG | 0644);
  87
  88         if (argc > 1)
  89                 usage(builtin_diff_usage);
  90
  91         stuff_change(&revs->diffopt,
  92                      mode, mode,
  93                      blob[0].sha1, blob[1].sha1,
  94                      blob[0].name, blob[1].name);
  95         diffcore_std(&revs->diffopt);
  96         diff_flush(&revs->diffopt);
  97         return 0;
  98 }
  99
 100 static int builtin_diff_index(struct rev_info *revs,
 101                               int argc, const char **argv)
 102 {
 103         int cached = 0;
 104         while (1 < argc) {
 105                 const char *arg = argv[1];
 106                 if (!strcmp(arg, "--cached"))
 107                         cached = 1;
 108                 else
 109                         usage(builtin_diff_usage);
 110                 argv++; argc--;
 111         }
 112         /*
 113          * Make sure there is one revision (i.e. pending object),
 114          * and there is no revision filtering parameters.
 115          */
 116         if (revs->pending.nr != 1 ||
 117             revs->max_count != -1 || revs->min_age != -1 ||
 118             revs->max_age != -1)
 119                 usage(builtin_diff_usage);
 120         if (read_cache() < 0) {
 121                 perror("read_cache");
 122                 return -1;
 123         }
 124         return run_diff_index(revs, cached);
 125 }
 126
 127 static int builtin_diff_tree(struct rev_info *revs,
 128                              int argc, const char **argv,
 129                              struct object_array_entry *ent)
 130 {
 131         const unsigned char *(sha1[2]);
 132         int swap = 0;
 133
 134         if (argc > 1)
 135                 usage(builtin_diff_usage);
 136
 137         /* We saw two trees, ent[0] and ent[1].
 138          * if ent[1] is uninteresting, they are swapped
 139          */
 140         if (ent[1].item->flags & UNINTERESTING)
 141                 swap = 1;
 142         sha1[swap] = ent[0].item->sha1;
 143         sha1[1-swap] = ent[1].item->sha1;
 144         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
 145         log_tree_diff_flush(revs);
 146         return 0;
 147 }
 148
 149 static int builtin_diff_combined(struct rev_info *revs,
 150                                  int argc, const char **argv,
 151                                  struct object_array_entry *ent,
 152                                  int ents)
 153 {
 154         const unsigned char (*parent)[20];
 155         int i;
 156
 157         if (argc > 1)
 158                 usage(builtin_diff_usage);
 159
 160         if (!revs->dense_combined_merges && !revs->combine_merges)
 161                 revs->dense_combined_merges = revs->combine_merges = 1;
 162         parent = xmalloc(ents * sizeof(*parent));
 163         /* Again, the revs are all reverse */
 164         for (i = 0; i < ents; i++)
 165                 hashcpy((unsigned char *)(parent + i),
 166                         ent[ents - 1 - i].item->sha1);
 167         diff_tree_combined(parent[0], parent + 1, ents - 1,
 168                            revs->dense_combined_merges, revs);
 169         return 0;
 170 }
 171
 172 void add_head(struct rev_info *revs)
 173 {
 174         unsigned char sha1[20];
 175         struct object *obj;
 176         if (get_sha1("HEAD", sha1))
 177                 return;
 178         obj = parse_object(sha1);
 179         if (!obj)
 180                 return;
 181         add_pending_object(revs, obj, "HEAD");
 182 }
 183
 184 int cmd_diff(int argc, const char **argv, const char *prefix)
 185 {
 186         int i;
 187         struct rev_info rev;
 188         struct object_array_entry ent[100];
 189         int ents = 0, blobs = 0, paths = 0;
 190         const char *path = NULL;
 191         struct blobinfo blob[2];
 192         int nongit = 0;
 193         int result = 0;
 194
 195         /*
 196          * We could get N tree-ish in the rev.pending_objects list.
 197          * Also there could be M blobs there, and P pathspecs.
 198          *
 199          * N=0, M=0:
 200          *      cache vs files (diff-files)
 201          * N=0, M=2:
 202          *      compare two random blobs.  P must be zero.
 203          * N=0, M=1, P=1:
 204          *      compare a blob with a working tree file.
 205          *
 206          * N=1, M=0:
 207          *      tree vs cache (diff-index --cached)
 208          *
 209          * N=2, M=0:
 210          *      tree vs tree (diff-tree)
 211          *
 212          * Other cases are errors.
 213          */
 214
 215         prefix = setup_git_directory_gently(&nongit);
 216         git_config(git_diff_ui_config);
 217         init_revisions(&rev, prefix);
 218
 219         if (!setup_diff_no_index(&rev, argc, argv, nongit, prefix))
 220                 argc = 0;
 221         else
 222                 argc = setup_revisions(argc, argv, &rev, NULL);
 223         if (!rev.diffopt.output_format) {
 224                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
 225                 if (diff_setup_done(&rev.diffopt) < 0)
 226                         die("diff_setup_done failed");
 227         }
 228         rev.diffopt.allow_external = 1;
 229
 230         /* Do we have --cached and not have a pending object, then
 231          * default to HEAD by hand.  Eek.
 232          */
 233         if (!rev.pending.nr) {
 234                 int i;
 235                 for (i = 1; i < argc; i++) {
 236                         const char *arg = argv[i];
 237                         if (!strcmp(arg, "--"))
 238                                 break;
 239                         else if (!strcmp(arg, "--cached")) {
 240                                 add_head(&rev);
 241                                 if (!rev.pending.nr)
 242                                         die("No HEAD commit to compare with (yet)");
 243                                 break;
 244                         }
 245                 }
 246         }
 247
 248         for (i = 0; i < rev.pending.nr; i++) {
 249                 struct object_array_entry *list = rev.pending.objects+i;
 250                 struct object *obj = list->item;
 251                 const char *name = list->name;
 252                 int flags = (obj->flags & UNINTERESTING);
 253                 if (!obj->parsed)
 254                         obj = parse_object(obj->sha1);
 255                 obj = deref_tag(obj, NULL, 0);
 256                 if (!obj)
 257                         die("invalid object '%s' given.", name);
 258                 if (obj->type == OBJ_COMMIT)
 259                         obj = &((struct commit *)obj)->tree->object;
 260                 if (obj->type == OBJ_TREE) {
 261                         if (ARRAY_SIZE(ent) <= ents)
 262                                 die("more than %d trees given: '%s'",
 263                                     (int) ARRAY_SIZE(ent), name);
 264                         obj->flags |= flags;
 265                         ent[ents].item = obj;
 266                         ent[ents].name = name;
 267                         ents++;
 268                         continue;
 269                 }
 270                 if (obj->type == OBJ_BLOB) {
 271                         if (2 <= blobs)
 272                                 die("more than two blobs given: '%s'", name);
 273                         hashcpy(blob[blobs].sha1, obj->sha1);
 274                         blob[blobs].name = name;
 275                         blobs++;
 276                         continue;
 277
 278                 }
 279                 die("unhandled object '%s' given.", name);
 280         }
 281         if (rev.prune_data) {
 282                 const char **pathspec = rev.prune_data;
 283                 while (*pathspec) {
 284                         if (!path)
 285                                 path = *pathspec;
 286                         paths++;
 287                         pathspec++;
 288                 }
 289         }
 290
 291         /*
 292          * Now, do the arguments look reasonable?
 293          */
 294         if (!ents) {
 295                 switch (blobs) {
 296                 case 0:
 297                         result = run_diff_files_cmd(&rev, argc, argv);
 298                         break;
 299                 case 1:
 300                         if (paths != 1)
 301                                 usage(builtin_diff_usage);
 302                         result = builtin_diff_b_f(&rev, argc, argv, blob, path);
 303                         break;
 304                 case 2:
 305                         if (paths)
 306                                 usage(builtin_diff_usage);
 307                         result = builtin_diff_blobs(&rev, argc, argv, blob);
 308                         break;
 309                 default:
 310                         usage(builtin_diff_usage);
 311                 }
 312         }
 313         else if (blobs)
 314                 usage(builtin_diff_usage);
 315         else if (ents == 1)
 316                 result = builtin_diff_index(&rev, argc, argv);
 317         else if (ents == 2)
 318                 result = builtin_diff_tree(&rev, argc, argv, ent);
 319         else if ((ents == 3) && (ent[0].item->flags & UNINTERESTING)) {
 320                 /* diff A...B where there is one sane merge base between
 321                  * A and B.  We have ent[0] == merge-base, ent[1] == A,
 322                  * and ent[2] == B.  Show diff between the base and B.
 323                  */
 324                 ent[1] = ent[2];
 325                 result = builtin_diff_tree(&rev, argc, argv, ent);
 326         }
 327         else
 328                 result = builtin_diff_combined(&rev, argc, argv,
 329                                              ent, ents);
 330         if (rev.diffopt.exit_with_status)
 331                 result = rev.diffopt.has_changes;
 332         return result;
 333 }