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 int builtin_diff_files(struct rev_info *revs,
  29                               int argc, const char **argv)
  30 {
  31         int silent = 0;
  32         while (1 < argc) {
  33                 const char *arg = argv[1];
  34                 if (!strcmp(arg, "--base"))
  35                         revs->max_count = 1;
  36                 else if (!strcmp(arg, "--ours"))
  37                         revs->max_count = 2;
  38                 else if (!strcmp(arg, "--theirs"))
  39                         revs->max_count = 3;
  40                 else if (!strcmp(arg, "-q"))
  41                         silent = 1;
  42                 else
  43                         usage(builtin_diff_usage);
  44                 argv++; argc--;
  45         }
  46         /*
  47          * Make sure there are NO revision (i.e. pending object) parameter,
  48          * specified rev.max_count is reasonable (0 <= n <= 3), and
  49          * there is no other revision filtering parameter.
  50          */
  51         if (revs->pending.nr ||
  52             revs->min_age != -1 ||
  53             revs->max_age != -1 ||
  54             3 < revs->max_count)
  55                 usage(builtin_diff_usage);
  56         if (revs->max_count < 0 &&
  57             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
  58                 revs->combine_merges = revs->dense_combined_merges = 1;
  59         /*
  60          * Backward compatibility wart - "diff-files -s" used to
  61          * defeat the common diff option "-s" which asked for
  62          * DIFF_FORMAT_NO_OUTPUT.
  63          */
  64         if (revs->diffopt.output_format == DIFF_FORMAT_NO_OUTPUT)
  65                 revs->diffopt.output_format = DIFF_FORMAT_RAW;
  66         return run_diff_files(revs, silent);
  67 }
  68
  69 static void stuff_change(struct diff_options *opt,
  70                          unsigned old_mode, unsigned new_mode,
  71                          const unsigned char *old_sha1,
  72                          const unsigned char *new_sha1,
  73                          const char *old_name,
  74                          const char *new_name)
  75 {
  76         struct diff_filespec *one, *two;
  77
  78         if (memcmp(null_sha1, old_sha1, 20) &&
  79             memcmp(null_sha1, new_sha1, 20) &&
  80             !memcmp(old_sha1, new_sha1, 20))
  81                 return;
  82
  83         if (opt->reverse_diff) {
  84                 unsigned tmp;
  85                 const unsigned char *tmp_u;
  86                 const char *tmp_c;
  87                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
  88                 tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
  89                 tmp_c = old_name; old_name = new_name; new_name = tmp_c;
  90         }
  91         one = alloc_filespec(old_name);
  92         two = alloc_filespec(new_name);
  93         fill_filespec(one, old_sha1, old_mode);
  94         fill_filespec(two, new_sha1, new_mode);
  95
  96         /* NEEDSWORK: shouldn't this part of diffopt??? */
  97         diff_queue(&diff_queued_diff, one, two);
  98 }
  99
 100 static int builtin_diff_b_f(struct rev_info *revs,
 101                             int argc, const char **argv,
 102                             struct blobinfo *blob,
 103                             const char *path)
 104 {
 105         /* Blob vs file in the working tree*/
 106         struct stat st;
 107
 108         if (argc > 1)
 109                 usage(builtin_diff_usage);
 110
 111         if (lstat(path, &st))
 112                 die("'%s': %s", path, strerror(errno));
 113         if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
 114                 die("'%s': not a regular file or symlink", path);
 115         stuff_change(&revs->diffopt,
 116                      canon_mode(st.st_mode), canon_mode(st.st_mode),
 117                      blob[0].sha1, null_sha1,
 118                      path, path);
 119         diffcore_std(&revs->diffopt);
 120         diff_flush(&revs->diffopt);
 121         return 0;
 122 }
 123
 124 static int builtin_diff_blobs(struct rev_info *revs,
 125                               int argc, const char **argv,
 126                               struct blobinfo *blob)
 127 {
 128         unsigned mode = canon_mode(S_IFREG | 0644);
 129
 130         if (argc > 1)
 131                 usage(builtin_diff_usage);
 132
 133         stuff_change(&revs->diffopt,
 134                      mode, mode,
 135                      blob[0].sha1, blob[1].sha1,
 136                      blob[0].name, blob[1].name);
 137         diffcore_std(&revs->diffopt);
 138         diff_flush(&revs->diffopt);
 139         return 0;
 140 }
 141
 142 static int builtin_diff_index(struct rev_info *revs,
 143                               int argc, const char **argv)
 144 {
 145         int cached = 0;
 146         while (1 < argc) {
 147                 const char *arg = argv[1];
 148                 if (!strcmp(arg, "--cached"))
 149                         cached = 1;
 150                 else
 151                         usage(builtin_diff_usage);
 152                 argv++; argc--;
 153         }
 154         /*
 155          * Make sure there is one revision (i.e. pending object),
 156          * and there is no revision filtering parameters.
 157          */
 158         if (revs->pending.nr != 1 ||
 159             revs->max_count != -1 || revs->min_age != -1 ||
 160             revs->max_age != -1)
 161                 usage(builtin_diff_usage);
 162         return run_diff_index(revs, cached);
 163 }
 164
 165 static int builtin_diff_tree(struct rev_info *revs,
 166                              int argc, const char **argv,
 167                              struct object_array_entry *ent)
 168 {
 169         const unsigned char *(sha1[2]);
 170         int swap = 0;
 171
 172         if (argc > 1)
 173                 usage(builtin_diff_usage);
 174
 175         /* We saw two trees, ent[0] and ent[1].
 176          * if ent[1] is uninteresting, they are swapped
 177          */
 178         if (ent[1].item->flags & UNINTERESTING)
 179                 swap = 1;
 180         sha1[swap] = ent[0].item->sha1;
 181         sha1[1-swap] = ent[1].item->sha1;
 182         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
 183         log_tree_diff_flush(revs);
 184         return 0;
 185 }
 186
 187 static int builtin_diff_combined(struct rev_info *revs,
 188                                  int argc, const char **argv,
 189                                  struct object_array_entry *ent,
 190                                  int ents)
 191 {
 192         const unsigned char (*parent)[20];
 193         int i;
 194
 195         if (argc > 1)
 196                 usage(builtin_diff_usage);
 197
 198         if (!revs->dense_combined_merges && !revs->combine_merges)
 199                 revs->dense_combined_merges = revs->combine_merges = 1;
 200         parent = xmalloc(ents * sizeof(*parent));
 201         /* Again, the revs are all reverse */
 202         for (i = 0; i < ents; i++)
 203                 memcpy(parent + i, ent[ents - 1 - i].item->sha1, 20);
 204         diff_tree_combined(parent[0], parent + 1, ents - 1,
 205                            revs->dense_combined_merges, revs);
 206         return 0;
 207 }
 208
 209 void add_head(struct rev_info *revs)
 210 {
 211         unsigned char sha1[20];
 212         struct object *obj;
 213         if (get_sha1("HEAD", sha1))
 214                 return;
 215         obj = parse_object(sha1);
 216         if (!obj)
 217                 return;
 218         add_pending_object(revs, obj, "HEAD");
 219 }
 220
 221 int cmd_diff(int argc, const char **argv, const char *prefix)
 222 {
 223         int i;
 224         struct rev_info rev;
 225         struct object_array_entry ent[100];
 226         int ents = 0, blobs = 0, paths = 0;
 227         const char *path = NULL;
 228         struct blobinfo blob[2];
 229
 230         /*
 231          * We could get N tree-ish in the rev.pending_objects list.
 232          * Also there could be M blobs there, and P pathspecs.
 233          *
 234          * N=0, M=0:
 235          *      cache vs files (diff-files)
 236          * N=0, M=2:
 237          *      compare two random blobs.  P must be zero.
 238          * N=0, M=1, P=1:
 239          *      compare a blob with a working tree file.
 240          *
 241          * N=1, M=0:
 242          *      tree vs cache (diff-index --cached)
 243          *
 244          * N=2, M=0:
 245          *      tree vs tree (diff-tree)
 246          *
 247          * Other cases are errors.
 248          */
 249
 250         git_config(git_diff_ui_config);
 251         init_revisions(&rev, prefix);
 252
 253         argc = setup_revisions(argc, argv, &rev, NULL);
 254         if (!rev.diffopt.output_format) {
 255                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
 256                 diff_setup_done(&rev.diffopt);
 257         }
 258
 259         /* Do we have --cached and not have a pending object, then
 260          * default to HEAD by hand.  Eek.
 261          */
 262         if (!rev.pending.nr) {
 263                 int i;
 264                 for (i = 1; i < argc; i++) {
 265                         const char *arg = argv[i];
 266                         if (!strcmp(arg, "--"))
 267                                 break;
 268                         else if (!strcmp(arg, "--cached")) {
 269                                 add_head(&rev);
 270                                 break;
 271                         }
 272                 }
 273         }
 274
 275         for (i = 0; i < rev.pending.nr; i++) {
 276                 struct object_array_entry *list = rev.pending.objects+i;
 277                 struct object *obj = list->item;
 278                 const char *name = list->name;
 279                 int flags = (obj->flags & UNINTERESTING);
 280                 if (!obj->parsed)
 281                         obj = parse_object(obj->sha1);
 282                 obj = deref_tag(obj, NULL, 0);
 283                 if (!obj)
 284                         die("invalid object '%s' given.", name);
 285                 if (obj->type == OBJ_COMMIT)
 286                         obj = &((struct commit *)obj)->tree->object;
 287                 if (obj->type == OBJ_TREE) {
 288                         if (ARRAY_SIZE(ent) <= ents)
 289                                 die("more than %d trees given: '%s'",
 290                                     (int) ARRAY_SIZE(ent), name);
 291                         obj->flags |= flags;
 292                         ent[ents].item = obj;
 293                         ent[ents].name = name;
 294                         ents++;
 295                         continue;
 296                 }
 297                 if (obj->type == OBJ_BLOB) {
 298                         if (2 <= blobs)
 299                                 die("more than two blobs given: '%s'", name);
 300                         memcpy(blob[blobs].sha1, obj->sha1, 20);
 301                         blob[blobs].name = name;
 302                         blobs++;
 303                         continue;
 304
 305                 }
 306                 die("unhandled object '%s' given.", name);
 307         }
 308         if (rev.prune_data) {
 309                 const char **pathspec = rev.prune_data;
 310                 while (*pathspec) {
 311                         if (!path)
 312                                 path = *pathspec;
 313                         paths++;
 314                         pathspec++;
 315                 }
 316         }
 317
 318         /*
 319          * Now, do the arguments look reasonable?
 320          */
 321         if (!ents) {
 322                 switch (blobs) {
 323                 case 0:
 324                         return builtin_diff_files(&rev, argc, argv);
 325                         break;
 326                 case 1:
 327                         if (paths != 1)
 328                                 usage(builtin_diff_usage);
 329                         return builtin_diff_b_f(&rev, argc, argv, blob, path);
 330                         break;
 331                 case 2:
 332                         if (paths)
 333                                 usage(builtin_diff_usage);
 334                         return builtin_diff_blobs(&rev, argc, argv, blob);
 335                         break;
 336                 default:
 337                         usage(builtin_diff_usage);
 338                 }
 339         }
 340         else if (blobs)
 341                 usage(builtin_diff_usage);
 342         else if (ents == 1)
 343                 return builtin_diff_index(&rev, argc, argv);
 344         else if (ents == 2)
 345                 return builtin_diff_tree(&rev, argc, argv, ent);
 346         else if ((ents == 3) && (ent[0].item->flags & UNINTERESTING)) {
 347                 /* diff A...B where there is one sane merge base between
 348                  * A and B.  We have ent[0] == merge-base, ent[1] == A,
 349                  * and ent[2] == B.  Show diff between the base and B.
 350                  */
 351                 return builtin_diff_tree(&rev, argc, argv, ent);
 352         }
 353         else
 354                 return builtin_diff_combined(&rev, argc, argv,
 355                                              ent, ents);
 356         usage(builtin_diff_usage);
 357 }