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