Merge branch 'jc/maint-blame-no-such-path'
[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 #include "sha1-array.h"
18
19 struct blobinfo {
20         unsigned char sha1[20];
21         const char *name;
22         unsigned mode;
23 };
24
25 static const char builtin_diff_usage[] =
26 "git diff [<options>] [<commit> [<commit>]] [--] [<path>...]";
27
28 static void stuff_change(struct diff_options *opt,
29                          unsigned old_mode, unsigned new_mode,
30                          const unsigned char *old_sha1,
31                          const unsigned char *new_sha1,
32                          int old_sha1_valid,
33                          int new_sha1_valid,
34                          const char *old_name,
35                          const char *new_name)
36 {
37         struct diff_filespec *one, *two;
38
39         if (!is_null_sha1(old_sha1) && !is_null_sha1(new_sha1) &&
40             !hashcmp(old_sha1, new_sha1) && (old_mode == new_mode))
41                 return;
42
43         if (DIFF_OPT_TST(opt, REVERSE_DIFF)) {
44                 unsigned tmp;
45                 const unsigned char *tmp_u;
46                 const char *tmp_c;
47                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
48                 tmp_u = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_u;
49                 tmp_c = old_name; old_name = new_name; new_name = tmp_c;
50         }
51
52         if (opt->prefix &&
53             (strncmp(old_name, opt->prefix, opt->prefix_length) ||
54              strncmp(new_name, opt->prefix, opt->prefix_length)))
55                 return;
56
57         one = alloc_filespec(old_name);
58         two = alloc_filespec(new_name);
59         fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
60         fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
61
62         diff_queue(&diff_queued_diff, one, two);
63 }
64
65 static int builtin_diff_b_f(struct rev_info *revs,
66                             int argc, const char **argv,
67                             struct blobinfo *blob,
68                             const char *path)
69 {
70         /* Blob vs file in the working tree*/
71         struct stat st;
72
73         if (argc > 1)
74                 usage(builtin_diff_usage);
75
76         if (lstat(path, &st))
77                 die_errno(_("failed to stat '%s'"), path);
78         if (!(S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)))
79                 die(_("'%s': not a regular file or symlink"), path);
80
81         diff_set_mnemonic_prefix(&revs->diffopt, "o/", "w/");
82
83         if (blob[0].mode == S_IFINVALID)
84                 blob[0].mode = canon_mode(st.st_mode);
85
86         stuff_change(&revs->diffopt,
87                      blob[0].mode, canon_mode(st.st_mode),
88                      blob[0].sha1, null_sha1,
89                      1, 0,
90                      path, path);
91         diffcore_std(&revs->diffopt);
92         diff_flush(&revs->diffopt);
93         return 0;
94 }
95
96 static int builtin_diff_blobs(struct rev_info *revs,
97                               int argc, const char **argv,
98                               struct blobinfo *blob)
99 {
100         unsigned mode = canon_mode(S_IFREG | 0644);
101
102         if (argc > 1)
103                 usage(builtin_diff_usage);
104
105         if (blob[0].mode == S_IFINVALID)
106                 blob[0].mode = mode;
107
108         if (blob[1].mode == S_IFINVALID)
109                 blob[1].mode = mode;
110
111         stuff_change(&revs->diffopt,
112                      blob[0].mode, blob[1].mode,
113                      blob[0].sha1, blob[1].sha1,
114                      1, 1,
115                      blob[0].name, blob[1].name);
116         diffcore_std(&revs->diffopt);
117         diff_flush(&revs->diffopt);
118         return 0;
119 }
120
121 static int builtin_diff_index(struct rev_info *revs,
122                               int argc, const char **argv)
123 {
124         int cached = 0;
125         while (1 < argc) {
126                 const char *arg = argv[1];
127                 if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
128                         cached = 1;
129                 else
130                         usage(builtin_diff_usage);
131                 argv++; argc--;
132         }
133         if (!cached)
134                 setup_work_tree();
135         /*
136          * Make sure there is one revision (i.e. pending object),
137          * and there is no revision filtering parameters.
138          */
139         if (revs->pending.nr != 1 ||
140             revs->max_count != -1 || revs->min_age != -1 ||
141             revs->max_age != -1)
142                 usage(builtin_diff_usage);
143         if (read_cache_preload(revs->diffopt.pathspec.raw) < 0) {
144                 perror("read_cache_preload");
145                 return -1;
146         }
147         return run_diff_index(revs, cached);
148 }
149
150 static int builtin_diff_tree(struct rev_info *revs,
151                              int argc, const char **argv,
152                              struct object_array_entry *ent)
153 {
154         const unsigned char *(sha1[2]);
155         int swap = 0;
156
157         if (argc > 1)
158                 usage(builtin_diff_usage);
159
160         /* We saw two trees, ent[0] and ent[1].
161          * if ent[1] is uninteresting, they are swapped
162          */
163         if (ent[1].item->flags & UNINTERESTING)
164                 swap = 1;
165         sha1[swap] = ent[0].item->sha1;
166         sha1[1-swap] = ent[1].item->sha1;
167         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
168         log_tree_diff_flush(revs);
169         return 0;
170 }
171
172 static int builtin_diff_combined(struct rev_info *revs,
173                                  int argc, const char **argv,
174                                  struct object_array_entry *ent,
175                                  int ents)
176 {
177         struct sha1_array parents = SHA1_ARRAY_INIT;
178         int i;
179
180         if (argc > 1)
181                 usage(builtin_diff_usage);
182
183         if (!revs->dense_combined_merges && !revs->combine_merges)
184                 revs->dense_combined_merges = revs->combine_merges = 1;
185         for (i = 1; i < ents; i++)
186                 sha1_array_append(&parents, ent[i].item->sha1);
187         diff_tree_combined(ent[0].item->sha1, &parents,
188                            revs->dense_combined_merges, revs);
189         sha1_array_clear(&parents);
190         return 0;
191 }
192
193 static void refresh_index_quietly(void)
194 {
195         struct lock_file *lock_file;
196         int fd;
197
198         lock_file = xcalloc(1, sizeof(struct lock_file));
199         fd = hold_locked_index(lock_file, 0);
200         if (fd < 0)
201                 return;
202         discard_cache();
203         read_cache();
204         refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
205         update_index_if_able(&the_index, lock_file);
206 }
207
208 static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
209 {
210         unsigned int options = 0;
211
212         while (1 < argc && argv[1][0] == '-') {
213                 if (!strcmp(argv[1], "--base"))
214                         revs->max_count = 1;
215                 else if (!strcmp(argv[1], "--ours"))
216                         revs->max_count = 2;
217                 else if (!strcmp(argv[1], "--theirs"))
218                         revs->max_count = 3;
219                 else if (!strcmp(argv[1], "-q"))
220                         options |= DIFF_SILENT_ON_REMOVED;
221                 else if (!strcmp(argv[1], "-h"))
222                         usage(builtin_diff_usage);
223                 else
224                         return error(_("invalid option: %s"), argv[1]);
225                 argv++; argc--;
226         }
227
228         /*
229          * "diff --base" should not combine merges because it was not
230          * asked to.  "diff -c" should not densify (if the user wants
231          * dense one, --cc can be explicitly asked for, or just rely
232          * on the default).
233          */
234         if (revs->max_count == -1 && !revs->combine_merges &&
235             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
236                 revs->combine_merges = revs->dense_combined_merges = 1;
237
238         setup_work_tree();
239         if (read_cache_preload(revs->diffopt.pathspec.raw) < 0) {
240                 perror("read_cache_preload");
241                 return -1;
242         }
243         return run_diff_files(revs, options);
244 }
245
246 int cmd_diff(int argc, const char **argv, const char *prefix)
247 {
248         int i;
249         struct rev_info rev;
250         struct object_array_entry ent[100];
251         int ents = 0, blobs = 0, paths = 0;
252         const char *path = NULL;
253         struct blobinfo blob[2];
254         int nongit;
255         int result = 0;
256
257         /*
258          * We could get N tree-ish in the rev.pending_objects list.
259          * Also there could be M blobs there, and P pathspecs.
260          *
261          * N=0, M=0:
262          *      cache vs files (diff-files)
263          * N=0, M=2:
264          *      compare two random blobs.  P must be zero.
265          * N=0, M=1, P=1:
266          *      compare a blob with a working tree file.
267          *
268          * N=1, M=0:
269          *      tree vs cache (diff-index --cached)
270          *
271          * N=2, M=0:
272          *      tree vs tree (diff-tree)
273          *
274          * N=0, M=0, P=2:
275          *      compare two filesystem entities (aka --no-index).
276          *
277          * Other cases are errors.
278          */
279
280         prefix = setup_git_directory_gently(&nongit);
281         gitmodules_config();
282         git_config(git_diff_ui_config, NULL);
283
284         init_revisions(&rev, prefix);
285
286         /* If this is a no-index diff, just run it and exit there. */
287         diff_no_index(&rev, argc, argv, nongit, prefix);
288
289         /* Otherwise, we are doing the usual "git" diff */
290         rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
291
292         /* Scale to real terminal size and respect statGraphWidth config */
293         rev.diffopt.stat_width = -1;
294         rev.diffopt.stat_graph_width = -1;
295
296         /* Default to let external and textconv be used */
297         DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
298         DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
299
300         if (nongit)
301                 die(_("Not a git repository"));
302         argc = setup_revisions(argc, argv, &rev, NULL);
303         if (!rev.diffopt.output_format) {
304                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
305                 diff_setup_done(&rev.diffopt);
306         }
307
308         DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
309
310         setup_diff_pager(&rev.diffopt);
311
312         /*
313          * Do we have --cached and not have a pending object, then
314          * default to HEAD by hand.  Eek.
315          */
316         if (!rev.pending.nr) {
317                 int i;
318                 for (i = 1; i < argc; i++) {
319                         const char *arg = argv[i];
320                         if (!strcmp(arg, "--"))
321                                 break;
322                         else if (!strcmp(arg, "--cached") ||
323                                  !strcmp(arg, "--staged")) {
324                                 add_head_to_pending(&rev);
325                                 if (!rev.pending.nr) {
326                                         struct tree *tree;
327                                         tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
328                                         add_pending_object(&rev, &tree->object, "HEAD");
329                                 }
330                                 break;
331                         }
332                 }
333         }
334
335         for (i = 0; i < rev.pending.nr; i++) {
336                 struct object_array_entry *list = rev.pending.objects+i;
337                 struct object *obj = list->item;
338                 const char *name = list->name;
339                 int flags = (obj->flags & UNINTERESTING);
340                 if (!obj->parsed)
341                         obj = parse_object(obj->sha1);
342                 obj = deref_tag(obj, NULL, 0);
343                 if (!obj)
344                         die(_("invalid object '%s' given."), name);
345                 if (obj->type == OBJ_COMMIT)
346                         obj = &((struct commit *)obj)->tree->object;
347                 if (obj->type == OBJ_TREE) {
348                         if (ARRAY_SIZE(ent) <= ents)
349                                 die(_("more than %d trees given: '%s'"),
350                                     (int) ARRAY_SIZE(ent), name);
351                         obj->flags |= flags;
352                         ent[ents].item = obj;
353                         ent[ents].name = name;
354                         ents++;
355                         continue;
356                 }
357                 if (obj->type == OBJ_BLOB) {
358                         if (2 <= blobs)
359                                 die(_("more than two blobs given: '%s'"), name);
360                         hashcpy(blob[blobs].sha1, obj->sha1);
361                         blob[blobs].name = name;
362                         blob[blobs].mode = list->mode;
363                         blobs++;
364                         continue;
365
366                 }
367                 die(_("unhandled object '%s' given."), name);
368         }
369         if (rev.prune_data.nr) {
370                 if (!path)
371                         path = rev.prune_data.items[0].match;
372                 paths += rev.prune_data.nr;
373         }
374
375         /*
376          * Now, do the arguments look reasonable?
377          */
378         if (!ents) {
379                 switch (blobs) {
380                 case 0:
381                         result = builtin_diff_files(&rev, argc, argv);
382                         break;
383                 case 1:
384                         if (paths != 1)
385                                 usage(builtin_diff_usage);
386                         result = builtin_diff_b_f(&rev, argc, argv, blob, path);
387                         break;
388                 case 2:
389                         if (paths)
390                                 usage(builtin_diff_usage);
391                         result = builtin_diff_blobs(&rev, argc, argv, blob);
392                         break;
393                 default:
394                         usage(builtin_diff_usage);
395                 }
396         }
397         else if (blobs)
398                 usage(builtin_diff_usage);
399         else if (ents == 1)
400                 result = builtin_diff_index(&rev, argc, argv);
401         else if (ents == 2)
402                 result = builtin_diff_tree(&rev, argc, argv, ent);
403         else if (ent[0].item->flags & UNINTERESTING) {
404                 /*
405                  * diff A...B where there is at least one merge base
406                  * between A and B.  We have ent[0] == merge-base,
407                  * ent[ents-2] == A, and ent[ents-1] == B.  Show diff
408                  * between the base and B.  Note that we pick one
409                  * merge base at random if there are more than one.
410                  */
411                 ent[1] = ent[ents-1];
412                 result = builtin_diff_tree(&rev, argc, argv, ent);
413         } else
414                 result = builtin_diff_combined(&rev, argc, argv,
415                                                ent, ents);
416         result = diff_result_code(&rev.diffopt, result);
417         if (1 < rev.diffopt.skip_stat_unmatch)
418                 refresh_index_quietly();
419         return result;
420 }
421
422 void setup_diff_pager(struct diff_options *opt)
423 {
424         /*
425          * If the user asked for our exit code, then either they want --quiet
426          * or --exit-code. We should definitely not bother with a pager in the
427          * former case, as we will generate no output. Since we still properly
428          * report our exit code even when a pager is run, we _could_ run a
429          * pager with --exit-code. But since we have not done so historically,
430          * and because it is easy to find people oneline advising "git diff
431          * --exit-code" in hooks and other scripts, we do not do so.
432          */
433         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
434             check_pager_config("diff") != 0)
435                 setup_pager();
436 }