git-merge: no reason to use cpio anymore
[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 struct blobinfo {
17         unsigned char sha1[20];
18         const char *name;
19         unsigned mode;
20 };
21
22 static const char builtin_diff_usage[] =
23 "git-diff <options> <rev>{0,2} -- <path>*";
24
25 static void stuff_change(struct diff_options *opt,
26                          unsigned old_mode, unsigned new_mode,
27                          const unsigned char *old_sha1,
28                          const unsigned char *new_sha1,
29                          const char *old_name,
30                          const char *new_name)
31 {
32         struct diff_filespec *one, *two;
33
34         if (!is_null_sha1(old_sha1) && !is_null_sha1(new_sha1) &&
35             !hashcmp(old_sha1, new_sha1) && (old_mode == new_mode))
36                 return;
37
38         if (opt->reverse_diff) {
39                 unsigned tmp;
40                 const unsigned char *tmp_u;
41                 const char *tmp_c;
42                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
43                 tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
44                 tmp_c = old_name; old_name = new_name; new_name = tmp_c;
45         }
46         one = alloc_filespec(old_name);
47         two = alloc_filespec(new_name);
48         fill_filespec(one, old_sha1, old_mode);
49         fill_filespec(two, new_sha1, new_mode);
50
51         /* NEEDSWORK: shouldn't this part of diffopt??? */
52         diff_queue(&diff_queued_diff, one, two);
53 }
54
55 static int builtin_diff_b_f(struct rev_info *revs,
56                             int argc, const char **argv,
57                             struct blobinfo *blob,
58                             const char *path)
59 {
60         /* Blob vs file in the working tree*/
61         struct stat st;
62
63         if (argc > 1)
64                 usage(builtin_diff_usage);
65
66         if (lstat(path, &st))
67                 die("'%s': %s", path, strerror(errno));
68         if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
69                 die("'%s': not a regular file or symlink", path);
70
71         if (blob[0].mode == S_IFINVALID)
72                 blob[0].mode = canon_mode(st.st_mode);
73
74         stuff_change(&revs->diffopt,
75                      blob[0].mode, canon_mode(st.st_mode),
76                      blob[0].sha1, null_sha1,
77                      path, path);
78         diffcore_std(&revs->diffopt);
79         diff_flush(&revs->diffopt);
80         return 0;
81 }
82
83 static int builtin_diff_blobs(struct rev_info *revs,
84                               int argc, const char **argv,
85                               struct blobinfo *blob)
86 {
87         unsigned mode = canon_mode(S_IFREG | 0644);
88
89         if (argc > 1)
90                 usage(builtin_diff_usage);
91
92         if (blob[0].mode == S_IFINVALID)
93                 blob[0].mode = mode;
94
95         if (blob[1].mode == S_IFINVALID)
96                 blob[1].mode = mode;
97
98         stuff_change(&revs->diffopt,
99                      blob[0].mode, blob[1].mode,
100                      blob[0].sha1, blob[1].sha1,
101                      blob[0].name, blob[1].name);
102         diffcore_std(&revs->diffopt);
103         diff_flush(&revs->diffopt);
104         return 0;
105 }
106
107 static int builtin_diff_index(struct rev_info *revs,
108                               int argc, const char **argv)
109 {
110         int cached = 0;
111         while (1 < argc) {
112                 const char *arg = argv[1];
113                 if (!strcmp(arg, "--cached"))
114                         cached = 1;
115                 else
116                         usage(builtin_diff_usage);
117                 argv++; argc--;
118         }
119         /*
120          * Make sure there is one revision (i.e. pending object),
121          * and there is no revision filtering parameters.
122          */
123         if (revs->pending.nr != 1 ||
124             revs->max_count != -1 || revs->min_age != -1 ||
125             revs->max_age != -1)
126                 usage(builtin_diff_usage);
127         if (read_cache() < 0) {
128                 perror("read_cache");
129                 return -1;
130         }
131         return run_diff_index(revs, cached);
132 }
133
134 static int builtin_diff_tree(struct rev_info *revs,
135                              int argc, const char **argv,
136                              struct object_array_entry *ent)
137 {
138         const unsigned char *(sha1[2]);
139         int swap = 0;
140
141         if (argc > 1)
142                 usage(builtin_diff_usage);
143
144         /* We saw two trees, ent[0] and ent[1].
145          * if ent[1] is uninteresting, they are swapped
146          */
147         if (ent[1].item->flags & UNINTERESTING)
148                 swap = 1;
149         sha1[swap] = ent[0].item->sha1;
150         sha1[1-swap] = ent[1].item->sha1;
151         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
152         log_tree_diff_flush(revs);
153         return 0;
154 }
155
156 static int builtin_diff_combined(struct rev_info *revs,
157                                  int argc, const char **argv,
158                                  struct object_array_entry *ent,
159                                  int ents)
160 {
161         const unsigned char (*parent)[20];
162         int i;
163
164         if (argc > 1)
165                 usage(builtin_diff_usage);
166
167         if (!revs->dense_combined_merges && !revs->combine_merges)
168                 revs->dense_combined_merges = revs->combine_merges = 1;
169         parent = xmalloc(ents * sizeof(*parent));
170         /* Again, the revs are all reverse */
171         for (i = 0; i < ents; i++)
172                 hashcpy((unsigned char *)(parent + i),
173                         ent[ents - 1 - i].item->sha1);
174         diff_tree_combined(parent[0], parent + 1, ents - 1,
175                            revs->dense_combined_merges, revs);
176         return 0;
177 }
178
179 void add_head(struct rev_info *revs)
180 {
181         unsigned char sha1[20];
182         struct object *obj;
183         if (get_sha1("HEAD", sha1))
184                 return;
185         obj = parse_object(sha1);
186         if (!obj)
187                 return;
188         add_pending_object(revs, obj, "HEAD");
189 }
190
191 static void refresh_index_quietly(void)
192 {
193         struct lock_file *lock_file;
194         int fd;
195
196         lock_file = xcalloc(1, sizeof(struct lock_file));
197         fd = hold_locked_index(lock_file, 0);
198         if (fd < 0)
199                 return;
200         discard_cache();
201         read_cache();
202         refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
203         if (active_cache_changed) {
204                 if (write_cache(fd, active_cache, active_nr) ||
205                     close(fd) ||
206                     commit_locked_index(lock_file))
207                         ; /*
208                            * silently ignore it -- we haven't mucked
209                            * with the real index.
210                            */
211         }
212         rollback_lock_file(lock_file);
213 }
214
215 int cmd_diff(int argc, const char **argv, const char *prefix)
216 {
217         int i;
218         struct rev_info rev;
219         struct object_array_entry ent[100];
220         int ents = 0, blobs = 0, paths = 0;
221         const char *path = NULL;
222         struct blobinfo blob[2];
223         int nongit = 0;
224         int result = 0;
225
226         /*
227          * We could get N tree-ish in the rev.pending_objects list.
228          * Also there could be M blobs there, and P pathspecs.
229          *
230          * N=0, M=0:
231          *      cache vs files (diff-files)
232          * N=0, M=2:
233          *      compare two random blobs.  P must be zero.
234          * N=0, M=1, P=1:
235          *      compare a blob with a working tree file.
236          *
237          * N=1, M=0:
238          *      tree vs cache (diff-index --cached)
239          *
240          * N=2, M=0:
241          *      tree vs tree (diff-tree)
242          *
243          * Other cases are errors.
244          */
245
246         prefix = setup_git_directory_gently(&nongit);
247         git_config(git_diff_ui_config);
248         init_revisions(&rev, prefix);
249         rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
250
251         if (!setup_diff_no_index(&rev, argc, argv, nongit, prefix))
252                 argc = 0;
253         else
254                 argc = setup_revisions(argc, argv, &rev, NULL);
255         if (!rev.diffopt.output_format) {
256                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
257                 if (diff_setup_done(&rev.diffopt) < 0)
258                         die("diff_setup_done failed");
259         }
260         rev.diffopt.allow_external = 1;
261         rev.diffopt.recursive = 1;
262
263         /* If the user asked for our exit code then don't start a
264          * pager or we would end up reporting its exit code instead.
265          */
266         if (!rev.diffopt.exit_with_status)
267                 setup_pager();
268
269         /* Do we have --cached and not have a pending object, then
270          * default to HEAD by hand.  Eek.
271          */
272         if (!rev.pending.nr) {
273                 int i;
274                 for (i = 1; i < argc; i++) {
275                         const char *arg = argv[i];
276                         if (!strcmp(arg, "--"))
277                                 break;
278                         else if (!strcmp(arg, "--cached")) {
279                                 add_head(&rev);
280                                 if (!rev.pending.nr)
281                                         die("No HEAD commit to compare with (yet)");
282                                 break;
283                         }
284                 }
285         }
286
287         for (i = 0; i < rev.pending.nr; i++) {
288                 struct object_array_entry *list = rev.pending.objects+i;
289                 struct object *obj = list->item;
290                 const char *name = list->name;
291                 int flags = (obj->flags & UNINTERESTING);
292                 if (!obj->parsed)
293                         obj = parse_object(obj->sha1);
294                 obj = deref_tag(obj, NULL, 0);
295                 if (!obj)
296                         die("invalid object '%s' given.", name);
297                 if (obj->type == OBJ_COMMIT)
298                         obj = &((struct commit *)obj)->tree->object;
299                 if (obj->type == OBJ_TREE) {
300                         if (ARRAY_SIZE(ent) <= ents)
301                                 die("more than %d trees given: '%s'",
302                                     (int) ARRAY_SIZE(ent), name);
303                         obj->flags |= flags;
304                         ent[ents].item = obj;
305                         ent[ents].name = name;
306                         ents++;
307                         continue;
308                 }
309                 if (obj->type == OBJ_BLOB) {
310                         if (2 <= blobs)
311                                 die("more than two blobs given: '%s'", name);
312                         hashcpy(blob[blobs].sha1, obj->sha1);
313                         blob[blobs].name = name;
314                         blob[blobs].mode = list->mode;
315                         blobs++;
316                         continue;
317
318                 }
319                 die("unhandled object '%s' given.", name);
320         }
321         if (rev.prune_data) {
322                 const char **pathspec = rev.prune_data;
323                 while (*pathspec) {
324                         if (!path)
325                                 path = *pathspec;
326                         paths++;
327                         pathspec++;
328                 }
329         }
330
331         /*
332          * Now, do the arguments look reasonable?
333          */
334         if (!ents) {
335                 switch (blobs) {
336                 case 0:
337                         result = run_diff_files_cmd(&rev, argc, argv);
338                         break;
339                 case 1:
340                         if (paths != 1)
341                                 usage(builtin_diff_usage);
342                         result = builtin_diff_b_f(&rev, argc, argv, blob, path);
343                         break;
344                 case 2:
345                         if (paths)
346                                 usage(builtin_diff_usage);
347                         result = builtin_diff_blobs(&rev, argc, argv, blob);
348                         break;
349                 default:
350                         usage(builtin_diff_usage);
351                 }
352         }
353         else if (blobs)
354                 usage(builtin_diff_usage);
355         else if (ents == 1)
356                 result = builtin_diff_index(&rev, argc, argv);
357         else if (ents == 2)
358                 result = builtin_diff_tree(&rev, argc, argv, ent);
359         else if ((ents == 3) && (ent[0].item->flags & UNINTERESTING)) {
360                 /* diff A...B where there is one sane merge base between
361                  * A and B.  We have ent[0] == merge-base, ent[1] == A,
362                  * and ent[2] == B.  Show diff between the base and B.
363                  */
364                 ent[1] = ent[2];
365                 result = builtin_diff_tree(&rev, argc, argv, ent);
366         }
367         else
368                 result = builtin_diff_combined(&rev, argc, argv,
369                                              ent, ents);
370         if (rev.diffopt.exit_with_status)
371                 result = rev.diffopt.has_changes;
372
373         if (1 < rev.diffopt.skip_stat_unmatch)
374                 refresh_index_quietly();
375         return result;
376 }