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[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         /* 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 }