Show both blob names from "git diff blob1 blob2"
[git] / 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         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 }