Merge branch 'jc/ls-remote-short-help'
[git] / builtin / diff.c
1 /*
2  * Builtin "git diff"
3  *
4  * Copyright (c) 2006 Junio C Hamano
5  */
6 #include "cache.h"
7 #include "color.h"
8 #include "commit.h"
9 #include "blob.h"
10 #include "tag.h"
11 #include "diff.h"
12 #include "diffcore.h"
13 #include "revision.h"
14 #include "log-tree.h"
15 #include "builtin.h"
16 #include "submodule.h"
17
18 struct blobinfo {
19         unsigned char sha1[20];
20         const char *name;
21         unsigned mode;
22 };
23
24 static const char builtin_diff_usage[] =
25 "git diff [<options>] [<commit> [<commit>]] [--] [<path>...]";
26
27 static void stuff_change(struct diff_options *opt,
28                          unsigned old_mode, unsigned new_mode,
29                          const unsigned char *old_sha1,
30                          const unsigned char *new_sha1,
31                          const char *old_name,
32                          const char *new_name)
33 {
34         struct diff_filespec *one, *two;
35
36         if (!is_null_sha1(old_sha1) && !is_null_sha1(new_sha1) &&
37             !hashcmp(old_sha1, new_sha1) && (old_mode == new_mode))
38                 return;
39
40         if (DIFF_OPT_TST(opt, REVERSE_DIFF)) {
41                 unsigned tmp;
42                 const unsigned char *tmp_u;
43                 const char *tmp_c;
44                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
45                 tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
46                 tmp_c = old_name; old_name = new_name; new_name = tmp_c;
47         }
48
49         if (opt->prefix &&
50             (strncmp(old_name, opt->prefix, opt->prefix_length) ||
51              strncmp(new_name, opt->prefix, opt->prefix_length)))
52                 return;
53
54         one = alloc_filespec(old_name);
55         two = alloc_filespec(new_name);
56         fill_filespec(one, old_sha1, old_mode);
57         fill_filespec(two, new_sha1, new_mode);
58
59         diff_queue(&diff_queued_diff, one, two);
60 }
61
62 static int builtin_diff_b_f(struct rev_info *revs,
63                             int argc, const char **argv,
64                             struct blobinfo *blob,
65                             const char *path)
66 {
67         /* Blob vs file in the working tree*/
68         struct stat st;
69
70         if (argc > 1)
71                 usage(builtin_diff_usage);
72
73         if (lstat(path, &st))
74                 die_errno(_("failed to stat '%s'"), path);
75         if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
76                 die(_("'%s': not a regular file or symlink"), path);
77
78         diff_set_mnemonic_prefix(&revs->diffopt, "o/", "w/");
79
80         if (blob[0].mode == S_IFINVALID)
81                 blob[0].mode = canon_mode(st.st_mode);
82
83         stuff_change(&revs->diffopt,
84                      blob[0].mode, canon_mode(st.st_mode),
85                      blob[0].sha1, null_sha1,
86                      path, path);
87         diffcore_std(&revs->diffopt);
88         diff_flush(&revs->diffopt);
89         return 0;
90 }
91
92 static int builtin_diff_blobs(struct rev_info *revs,
93                               int argc, const char **argv,
94                               struct blobinfo *blob)
95 {
96         unsigned mode = canon_mode(S_IFREG | 0644);
97
98         if (argc > 1)
99                 usage(builtin_diff_usage);
100
101         if (blob[0].mode == S_IFINVALID)
102                 blob[0].mode = mode;
103
104         if (blob[1].mode == S_IFINVALID)
105                 blob[1].mode = mode;
106
107         stuff_change(&revs->diffopt,
108                      blob[0].mode, blob[1].mode,
109                      blob[0].sha1, blob[1].sha1,
110                      blob[0].name, blob[1].name);
111         diffcore_std(&revs->diffopt);
112         diff_flush(&revs->diffopt);
113         return 0;
114 }
115
116 static int builtin_diff_index(struct rev_info *revs,
117                               int argc, const char **argv)
118 {
119         int cached = 0;
120         while (1 < argc) {
121                 const char *arg = argv[1];
122                 if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
123                         cached = 1;
124                 else
125                         usage(builtin_diff_usage);
126                 argv++; argc--;
127         }
128         if (!cached)
129                 setup_work_tree();
130         /*
131          * Make sure there is one revision (i.e. pending object),
132          * and there is no revision filtering parameters.
133          */
134         if (revs->pending.nr != 1 ||
135             revs->max_count != -1 || revs->min_age != -1 ||
136             revs->max_age != -1)
137                 usage(builtin_diff_usage);
138         if (read_cache_preload(revs->diffopt.pathspec.raw) < 0) {
139                 perror("read_cache_preload");
140                 return -1;
141         }
142         return run_diff_index(revs, cached);
143 }
144
145 static int builtin_diff_tree(struct rev_info *revs,
146                              int argc, const char **argv,
147                              struct object_array_entry *ent)
148 {
149         const unsigned char *(sha1[2]);
150         int swap = 0;
151
152         if (argc > 1)
153                 usage(builtin_diff_usage);
154
155         /* We saw two trees, ent[0] and ent[1].
156          * if ent[1] is uninteresting, they are swapped
157          */
158         if (ent[1].item->flags & UNINTERESTING)
159                 swap = 1;
160         sha1[swap] = ent[0].item->sha1;
161         sha1[1-swap] = ent[1].item->sha1;
162         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
163         log_tree_diff_flush(revs);
164         return 0;
165 }
166
167 static int builtin_diff_combined(struct rev_info *revs,
168                                  int argc, const char **argv,
169                                  struct object_array_entry *ent,
170                                  int ents)
171 {
172         const unsigned char (*parent)[20];
173         int i;
174
175         if (argc > 1)
176                 usage(builtin_diff_usage);
177
178         if (!revs->dense_combined_merges && !revs->combine_merges)
179                 revs->dense_combined_merges = revs->combine_merges = 1;
180         parent = xmalloc(ents * sizeof(*parent));
181         for (i = 0; i < ents; i++)
182                 hashcpy((unsigned char *)(parent + i), ent[i].item->sha1);
183         diff_tree_combined(parent[0], parent + 1, ents - 1,
184                            revs->dense_combined_merges, revs);
185         free(parent);
186         return 0;
187 }
188
189 static void refresh_index_quietly(void)
190 {
191         struct lock_file *lock_file;
192         int fd;
193
194         lock_file = xcalloc(1, sizeof(struct lock_file));
195         fd = hold_locked_index(lock_file, 0);
196         if (fd < 0)
197                 return;
198         discard_cache();
199         read_cache();
200         refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
201         update_index_if_able(&the_index, lock_file);
202 }
203
204 static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
205 {
206         unsigned int options = 0;
207
208         while (1 < argc && argv[1][0] == '-') {
209                 if (!strcmp(argv[1], "--base"))
210                         revs->max_count = 1;
211                 else if (!strcmp(argv[1], "--ours"))
212                         revs->max_count = 2;
213                 else if (!strcmp(argv[1], "--theirs"))
214                         revs->max_count = 3;
215                 else if (!strcmp(argv[1], "-q"))
216                         options |= DIFF_SILENT_ON_REMOVED;
217                 else if (!strcmp(argv[1], "-h"))
218                         usage(builtin_diff_usage);
219                 else
220                         return error(_("invalid option: %s"), argv[1]);
221                 argv++; argc--;
222         }
223
224         /*
225          * "diff --base" should not combine merges because it was not
226          * asked to.  "diff -c" should not densify (if the user wants
227          * dense one, --cc can be explicitly asked for, or just rely
228          * on the default).
229          */
230         if (revs->max_count == -1 && !revs->combine_merges &&
231             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
232                 revs->combine_merges = revs->dense_combined_merges = 1;
233
234         setup_work_tree();
235         if (read_cache_preload(revs->diffopt.pathspec.raw) < 0) {
236                 perror("read_cache_preload");
237                 return -1;
238         }
239         return run_diff_files(revs, options);
240 }
241
242 int cmd_diff(int argc, const char **argv, const char *prefix)
243 {
244         int i;
245         struct rev_info rev;
246         struct object_array_entry ent[100];
247         int ents = 0, blobs = 0, paths = 0;
248         const char *path = NULL;
249         struct blobinfo blob[2];
250         int nongit;
251         int result = 0;
252
253         /*
254          * We could get N tree-ish in the rev.pending_objects list.
255          * Also there could be M blobs there, and P pathspecs.
256          *
257          * N=0, M=0:
258          *      cache vs files (diff-files)
259          * N=0, M=2:
260          *      compare two random blobs.  P must be zero.
261          * N=0, M=1, P=1:
262          *      compare a blob with a working tree file.
263          *
264          * N=1, M=0:
265          *      tree vs cache (diff-index --cached)
266          *
267          * N=2, M=0:
268          *      tree vs tree (diff-tree)
269          *
270          * N=0, M=0, P=2:
271          *      compare two filesystem entities (aka --no-index).
272          *
273          * Other cases are errors.
274          */
275
276         prefix = setup_git_directory_gently(&nongit);
277         gitmodules_config();
278         git_config(git_diff_ui_config, NULL);
279
280         init_revisions(&rev, prefix);
281
282         /* If this is a no-index diff, just run it and exit there. */
283         diff_no_index(&rev, argc, argv, nongit, prefix);
284
285         /* Otherwise, we are doing the usual "git" diff */
286         rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
287
288         /* Default to let external and textconv be used */
289         DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
290         DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
291
292         if (nongit)
293                 die(_("Not a git repository"));
294         argc = setup_revisions(argc, argv, &rev, NULL);
295         if (!rev.diffopt.output_format) {
296                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
297                 if (diff_setup_done(&rev.diffopt) < 0)
298                         die(_("diff_setup_done failed"));
299         }
300
301         DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
302
303         /*
304          * If the user asked for our exit code then don't start a
305          * pager or we would end up reporting its exit code instead.
306          */
307         if (!DIFF_OPT_TST(&rev.diffopt, EXIT_WITH_STATUS) &&
308             check_pager_config("diff") != 0)
309                 setup_pager();
310
311         /*
312          * Do we have --cached and not have a pending object, then
313          * default to HEAD by hand.  Eek.
314          */
315         if (!rev.pending.nr) {
316                 int i;
317                 for (i = 1; i < argc; i++) {
318                         const char *arg = argv[i];
319                         if (!strcmp(arg, "--"))
320                                 break;
321                         else if (!strcmp(arg, "--cached") ||
322                                  !strcmp(arg, "--staged")) {
323                                 add_head_to_pending(&rev);
324                                 if (!rev.pending.nr) {
325                                         struct tree *tree;
326                                         tree = lookup_tree((const unsigned char*)EMPTY_TREE_SHA1_BIN);
327                                         add_pending_object(&rev, &tree->object, "HEAD");
328                                 }
329                                 break;
330                         }
331                 }
332         }
333
334         for (i = 0; i < rev.pending.nr; i++) {
335                 struct object_array_entry *list = rev.pending.objects+i;
336                 struct object *obj = list->item;
337                 const char *name = list->name;
338                 int flags = (obj->flags & UNINTERESTING);
339                 if (!obj->parsed)
340                         obj = parse_object(obj->sha1);
341                 obj = deref_tag(obj, NULL, 0);
342                 if (!obj)
343                         die(_("invalid object '%s' given."), name);
344                 if (obj->type == OBJ_COMMIT)
345                         obj = &((struct commit *)obj)->tree->object;
346                 if (obj->type == OBJ_TREE) {
347                         if (ARRAY_SIZE(ent) <= ents)
348                                 die(_("more than %d trees given: '%s'"),
349                                     (int) ARRAY_SIZE(ent), name);
350                         obj->flags |= flags;
351                         ent[ents].item = obj;
352                         ent[ents].name = name;
353                         ents++;
354                         continue;
355                 }
356                 if (obj->type == OBJ_BLOB) {
357                         if (2 <= blobs)
358                                 die(_("more than two blobs given: '%s'"), name);
359                         hashcpy(blob[blobs].sha1, obj->sha1);
360                         blob[blobs].name = name;
361                         blob[blobs].mode = list->mode;
362                         blobs++;
363                         continue;
364
365                 }
366                 die(_("unhandled object '%s' given."), name);
367         }
368         if (rev.prune_data.nr) {
369                 if (!path)
370                         path = rev.prune_data.items[0].match;
371                 paths += rev.prune_data.nr;
372         }
373
374         /*
375          * Now, do the arguments look reasonable?
376          */
377         if (!ents) {
378                 switch (blobs) {
379                 case 0:
380                         result = builtin_diff_files(&rev, argc, argv);
381                         break;
382                 case 1:
383                         if (paths != 1)
384                                 usage(builtin_diff_usage);
385                         result = builtin_diff_b_f(&rev, argc, argv, blob, path);
386                         break;
387                 case 2:
388                         if (paths)
389                                 usage(builtin_diff_usage);
390                         result = builtin_diff_blobs(&rev, argc, argv, blob);
391                         break;
392                 default:
393                         usage(builtin_diff_usage);
394                 }
395         }
396         else if (blobs)
397                 usage(builtin_diff_usage);
398         else if (ents == 1)
399                 result = builtin_diff_index(&rev, argc, argv);
400         else if (ents == 2)
401                 result = builtin_diff_tree(&rev, argc, argv, ent);
402         else if (ent[0].item->flags & UNINTERESTING) {
403                 /*
404                  * diff A...B where there is at least one merge base
405                  * between A and B.  We have ent[0] == merge-base,
406                  * ent[ents-2] == A, and ent[ents-1] == B.  Show diff
407                  * between the base and B.  Note that we pick one
408                  * merge base at random if there are more than one.
409                  */
410                 ent[1] = ent[ents-1];
411                 result = builtin_diff_tree(&rev, argc, argv, ent);
412         } else
413                 result = builtin_diff_combined(&rev, argc, argv,
414                                                ent, ents);
415         result = diff_result_code(&rev.diffopt, result);
416         if (1 < rev.diffopt.skip_stat_unmatch)
417                 refresh_index_quietly();
418         return result;
419 }