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 "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         /* Blobs: the arguments are reversed when setup_revisions()
 129          * picked them up.
 130          */
 131         unsigned mode = canon_mode(S_IFREG | 0644);
 132
 133         if (argc > 1)
 134                 usage(builtin_diff_usage);
 135
 136         stuff_change(&revs->diffopt,
 137                      mode, mode,
 138                      blob[1].sha1, blob[0].sha1,
 139                      blob[0].name, blob[0].name);
 140         diffcore_std(&revs->diffopt);
 141         diff_flush(&revs->diffopt);
 142         return 0;
 143 }
 144
 145 static int builtin_diff_index(struct rev_info *revs,
 146                               int argc, const char **argv)
 147 {
 148         int cached = 0;
 149         while (1 < argc) {
 150                 const char *arg = argv[1];
 151                 if (!strcmp(arg, "--cached"))
 152                         cached = 1;
 153                 else
 154                         usage(builtin_diff_usage);
 155                 argv++; argc--;
 156         }
 157         /*
 158          * Make sure there is one revision (i.e. pending object),
 159          * and there is no revision filtering parameters.
 160          */
 161         if (revs->pending.nr != 1 ||
 162             revs->max_count != -1 || revs->min_age != -1 ||
 163             revs->max_age != -1)
 164                 usage(builtin_diff_usage);
 165         return run_diff_index(revs, cached);
 166 }
 167
 168 static int builtin_diff_tree(struct rev_info *revs,
 169                              int argc, const char **argv,
 170                              struct object_array_entry *ent)
 171 {
 172         const unsigned char *(sha1[2]);
 173         int swap = 0;
 174
 175         if (argc > 1)
 176                 usage(builtin_diff_usage);
 177
 178         /* We saw two trees, ent[0] and ent[1].
 179          * if ent[1] is uninteresting, they are swapped
 180          */
 181         if (ent[1].item->flags & UNINTERESTING)
 182                 swap = 1;
 183         sha1[swap] = ent[0].item->sha1;
 184         sha1[1-swap] = ent[1].item->sha1;
 185         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
 186         log_tree_diff_flush(revs);
 187         return 0;
 188 }
 189
 190 static int builtin_diff_combined(struct rev_info *revs,
 191                                  int argc, const char **argv,
 192                                  struct object_array_entry *ent,
 193                                  int ents)
 194 {
 195         const unsigned char (*parent)[20];
 196         int i;
 197
 198         if (argc > 1)
 199                 usage(builtin_diff_usage);
 200
 201         if (!revs->dense_combined_merges && !revs->combine_merges)
 202                 revs->dense_combined_merges = revs->combine_merges = 1;
 203         parent = xmalloc(ents * sizeof(*parent));
 204         /* Again, the revs are all reverse */
 205         for (i = 0; i < ents; i++)
 206                 memcpy(parent + i, ent[ents - 1 - i].item->sha1, 20);
 207         diff_tree_combined(parent[0], parent + 1, ents - 1,
 208                            revs->dense_combined_merges, revs);
 209         return 0;
 210 }
 211
 212 void add_head(struct rev_info *revs)
 213 {
 214         unsigned char sha1[20];
 215         struct object *obj;
 216         if (get_sha1("HEAD", sha1))
 217                 return;
 218         obj = parse_object(sha1);
 219         if (!obj)
 220                 return;
 221         add_pending_object(revs, obj, "HEAD");
 222 }
 223
 224 int cmd_diff(int argc, const char **argv, const char *prefix)
 225 {
 226         int i;
 227         struct rev_info rev;
 228         struct object_array_entry ent[100];
 229         int ents = 0, blobs = 0, paths = 0;
 230         const char *path = NULL;
 231         struct blobinfo blob[2];
 232
 233         /*
 234          * We could get N tree-ish in the rev.pending_objects list.
 235          * Also there could be M blobs there, and P pathspecs.
 236          *
 237          * N=0, M=0:
 238          *      cache vs files (diff-files)
 239          * N=0, M=2:
 240          *      compare two random blobs.  P must be zero.
 241          * N=0, M=1, P=1:
 242          *      compare a blob with a working tree file.
 243          *
 244          * N=1, M=0:
 245          *      tree vs cache (diff-index --cached)
 246          *
 247          * N=2, M=0:
 248          *      tree vs tree (diff-tree)
 249          *
 250          * Other cases are errors.
 251          */
 252
 253         git_config(git_diff_ui_config);
 254         init_revisions(&rev, prefix);
 255
 256         argc = setup_revisions(argc, argv, &rev, NULL);
 257         if (!rev.diffopt.output_format) {
 258                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
 259                 diff_setup_done(&rev.diffopt);
 260         }
 261
 262         /* Do we have --cached and not have a pending object, then
 263          * default to HEAD by hand.  Eek.
 264          */
 265         if (!rev.pending.nr) {
 266                 int i;
 267                 for (i = 1; i < argc; i++) {
 268                         const char *arg = argv[i];
 269                         if (!strcmp(arg, "--"))
 270                                 break;
 271                         else if (!strcmp(arg, "--cached")) {
 272                                 add_head(&rev);
 273                                 break;
 274                         }
 275                 }
 276         }
 277
 278         for (i = 0; i < rev.pending.nr; i++) {
 279                 struct object_array_entry *list = rev.pending.objects+i;
 280                 struct object *obj = list->item;
 281                 const char *name = list->name;
 282                 int flags = (obj->flags & UNINTERESTING);
 283                 if (!obj->parsed)
 284                         obj = parse_object(obj->sha1);
 285                 obj = deref_tag(obj, NULL, 0);
 286                 if (!obj)
 287                         die("invalid object '%s' given.", name);
 288                 if (obj->type == OBJ_COMMIT)
 289                         obj = &((struct commit *)obj)->tree->object;
 290                 if (obj->type == OBJ_TREE) {
 291                         if (ARRAY_SIZE(ent) <= ents)
 292                                 die("more than %d trees given: '%s'",
 293                                     (int) ARRAY_SIZE(ent), name);
 294                         obj->flags |= flags;
 295                         ent[ents].item = obj;
 296                         ent[ents].name = name;
 297                         ents++;
 298                         continue;
 299                 }
 300                 if (obj->type == OBJ_BLOB) {
 301                         if (2 <= blobs)
 302                                 die("more than two blobs given: '%s'", name);
 303                         memcpy(blob[blobs].sha1, obj->sha1, 20);
 304                         blob[blobs].name = name;
 305                         blobs++;
 306                         continue;
 307
 308                 }
 309                 die("unhandled object '%s' given.", name);
 310         }
 311         if (rev.prune_data) {
 312                 const char **pathspec = rev.prune_data;
 313                 while (*pathspec) {
 314                         if (!path)
 315                                 path = *pathspec;
 316                         paths++;
 317                         pathspec++;
 318                 }
 319         }
 320
 321         /*
 322          * Now, do the arguments look reasonable?
 323          */
 324         if (!ents) {
 325                 switch (blobs) {
 326                 case 0:
 327                         return builtin_diff_files(&rev, argc, argv);
 328                         break;
 329                 case 1:
 330                         if (paths != 1)
 331                                 usage(builtin_diff_usage);
 332                         return builtin_diff_b_f(&rev, argc, argv, blob, path);
 333                         break;
 334                 case 2:
 335                         if (paths)
 336                                 usage(builtin_diff_usage);
 337                         return builtin_diff_blobs(&rev, argc, argv, blob);
 338                         break;
 339                 default:
 340                         usage(builtin_diff_usage);
 341                 }
 342         }
 343         else if (blobs)
 344                 usage(builtin_diff_usage);
 345         else if (ents == 1)
 346                 return builtin_diff_index(&rev, argc, argv);
 347         else if (ents == 2)
 348                 return builtin_diff_tree(&rev, argc, argv, ent);
 349         else if ((ents == 3) && (ent[0].item->flags & UNINTERESTING)) {
 350                 /* diff A...B where there is one sane merge base between
 351                  * A and B.  We have ent[0] == merge-base, ent[1] == A,
 352                  * and ent[2] == B.  Show diff between the base and B.
 353                  */
 354                 return builtin_diff_tree(&rev, argc, argv, ent);
 355         }
 356         else
 357                 return builtin_diff_combined(&rev, argc, argv,
 358                                              ent, ents);
 359         usage(builtin_diff_usage);
 360 }