Merge branch 'jj/doc-markup-hints-in-coding-guidelines'
[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         /*
134          * Make sure there is one revision (i.e. pending object),
135          * and there is no revision filtering parameters.
136          */
137         if (revs->pending.nr != 1 ||
138             revs->max_count != -1 || revs->min_age != -1 ||
139             revs->max_age != -1)
140                 usage(builtin_diff_usage);
141         if (!cached) {
142                 setup_work_tree();
143                 if (read_cache_preload(&revs->diffopt.pathspec) < 0) {
144                         perror("read_cache_preload");
145                         return -1;
146                 }
147         } else if (read_cache() < 0) {
148                 perror("read_cache");
149                 return -1;
150         }
151         return run_diff_index(revs, cached);
152 }
153
154 static int builtin_diff_tree(struct rev_info *revs,
155                              int argc, const char **argv,
156                              struct object_array_entry *ent0,
157                              struct object_array_entry *ent1)
158 {
159         const unsigned char *(sha1[2]);
160         int swap = 0;
161
162         if (argc > 1)
163                 usage(builtin_diff_usage);
164
165         /*
166          * We saw two trees, ent0 and ent1.  If ent1 is uninteresting,
167          * swap them.
168          */
169         if (ent1->item->flags & UNINTERESTING)
170                 swap = 1;
171         sha1[swap] = ent0->item->sha1;
172         sha1[1 - swap] = ent1->item->sha1;
173         diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
174         log_tree_diff_flush(revs);
175         return 0;
176 }
177
178 static int builtin_diff_combined(struct rev_info *revs,
179                                  int argc, const char **argv,
180                                  struct object_array_entry *ent,
181                                  int ents)
182 {
183         struct sha1_array parents = SHA1_ARRAY_INIT;
184         int i;
185
186         if (argc > 1)
187                 usage(builtin_diff_usage);
188
189         if (!revs->dense_combined_merges && !revs->combine_merges)
190                 revs->dense_combined_merges = revs->combine_merges = 1;
191         for (i = 1; i < ents; i++)
192                 sha1_array_append(&parents, ent[i].item->sha1);
193         diff_tree_combined(ent[0].item->sha1, &parents,
194                            revs->dense_combined_merges, revs);
195         sha1_array_clear(&parents);
196         return 0;
197 }
198
199 static void refresh_index_quietly(void)
200 {
201         struct lock_file *lock_file;
202         int fd;
203
204         lock_file = xcalloc(1, sizeof(struct lock_file));
205         fd = hold_locked_index(lock_file, 0);
206         if (fd < 0)
207                 return;
208         discard_cache();
209         read_cache();
210         refresh_cache(REFRESH_QUIET|REFRESH_UNMERGED);
211         update_index_if_able(&the_index, lock_file);
212 }
213
214 static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv)
215 {
216         unsigned int options = 0;
217
218         while (1 < argc && argv[1][0] == '-') {
219                 if (!strcmp(argv[1], "--base"))
220                         revs->max_count = 1;
221                 else if (!strcmp(argv[1], "--ours"))
222                         revs->max_count = 2;
223                 else if (!strcmp(argv[1], "--theirs"))
224                         revs->max_count = 3;
225                 else if (!strcmp(argv[1], "-q"))
226                         options |= DIFF_SILENT_ON_REMOVED;
227                 else if (!strcmp(argv[1], "-h"))
228                         usage(builtin_diff_usage);
229                 else
230                         return error(_("invalid option: %s"), argv[1]);
231                 argv++; argc--;
232         }
233
234         /*
235          * "diff --base" should not combine merges because it was not
236          * asked to.  "diff -c" should not densify (if the user wants
237          * dense one, --cc can be explicitly asked for, or just rely
238          * on the default).
239          */
240         if (revs->max_count == -1 && !revs->combine_merges &&
241             (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
242                 revs->combine_merges = revs->dense_combined_merges = 1;
243
244         setup_work_tree();
245         if (read_cache_preload(&revs->diffopt.pathspec) < 0) {
246                 perror("read_cache_preload");
247                 return -1;
248         }
249         return run_diff_files(revs, options);
250 }
251
252 int cmd_diff(int argc, const char **argv, const char *prefix)
253 {
254         int i;
255         struct rev_info rev;
256         struct object_array ent = OBJECT_ARRAY_INIT;
257         int blobs = 0, paths = 0;
258         const char *path = NULL;
259         struct blobinfo blob[2];
260         int nongit;
261         int result = 0;
262
263         /*
264          * We could get N tree-ish in the rev.pending_objects list.
265          * Also there could be M blobs there, and P pathspecs.
266          *
267          * N=0, M=0:
268          *      cache vs files (diff-files)
269          * N=0, M=2:
270          *      compare two random blobs.  P must be zero.
271          * N=0, M=1, P=1:
272          *      compare a blob with a working tree file.
273          *
274          * N=1, M=0:
275          *      tree vs cache (diff-index --cached)
276          *
277          * N=2, M=0:
278          *      tree vs tree (diff-tree)
279          *
280          * N=0, M=0, P=2:
281          *      compare two filesystem entities (aka --no-index).
282          *
283          * Other cases are errors.
284          */
285
286         prefix = setup_git_directory_gently(&nongit);
287         gitmodules_config();
288         git_config(git_diff_ui_config, NULL);
289
290         init_revisions(&rev, prefix);
291
292         /* If this is a no-index diff, just run it and exit there. */
293         diff_no_index(&rev, argc, argv, nongit, prefix);
294
295         /* Otherwise, we are doing the usual "git" diff */
296         rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
297
298         /* Scale to real terminal size and respect statGraphWidth config */
299         rev.diffopt.stat_width = -1;
300         rev.diffopt.stat_graph_width = -1;
301
302         /* Default to let external and textconv be used */
303         DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
304         DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
305
306         if (nongit)
307                 die(_("Not a git repository"));
308         argc = setup_revisions(argc, argv, &rev, NULL);
309         if (!rev.diffopt.output_format) {
310                 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
311                 diff_setup_done(&rev.diffopt);
312         }
313
314         DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
315
316         setup_diff_pager(&rev.diffopt);
317
318         /*
319          * Do we have --cached and not have a pending object, then
320          * default to HEAD by hand.  Eek.
321          */
322         if (!rev.pending.nr) {
323                 int i;
324                 for (i = 1; i < argc; i++) {
325                         const char *arg = argv[i];
326                         if (!strcmp(arg, "--"))
327                                 break;
328                         else if (!strcmp(arg, "--cached") ||
329                                  !strcmp(arg, "--staged")) {
330                                 add_head_to_pending(&rev);
331                                 if (!rev.pending.nr) {
332                                         struct tree *tree;
333                                         tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
334                                         add_pending_object(&rev, &tree->object, "HEAD");
335                                 }
336                                 break;
337                         }
338                 }
339         }
340
341         for (i = 0; i < rev.pending.nr; i++) {
342                 struct object_array_entry *entry = &rev.pending.objects[i];
343                 struct object *obj = entry->item;
344                 const char *name = entry->name;
345                 int flags = (obj->flags & UNINTERESTING);
346                 if (!obj->parsed)
347                         obj = parse_object(obj->sha1);
348                 obj = deref_tag(obj, NULL, 0);
349                 if (!obj)
350                         die(_("invalid object '%s' given."), name);
351                 if (obj->type == OBJ_COMMIT)
352                         obj = &((struct commit *)obj)->tree->object;
353
354                 if (obj->type == OBJ_TREE) {
355                         obj->flags |= flags;
356                         add_object_array(obj, name, &ent);
357                 } else 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 = entry->mode;
363                         blobs++;
364
365                 } else {
366                         die(_("unhandled object '%s' given."), name);
367                 }
368         }
369         if (rev.prune_data.nr) {
370                 /* builtin_diff_b_f() */
371                 GUARD_PATHSPEC(&rev.prune_data, PATHSPEC_FROMTOP | PATHSPEC_LITERAL);
372                 if (!path)
373                         path = rev.prune_data.items[0].match;
374                 paths += rev.prune_data.nr;
375         }
376
377         /*
378          * Now, do the arguments look reasonable?
379          */
380         if (!ent.nr) {
381                 switch (blobs) {
382                 case 0:
383                         result = builtin_diff_files(&rev, argc, argv);
384                         break;
385                 case 1:
386                         if (paths != 1)
387                                 usage(builtin_diff_usage);
388                         result = builtin_diff_b_f(&rev, argc, argv, blob, path);
389                         break;
390                 case 2:
391                         if (paths)
392                                 usage(builtin_diff_usage);
393                         result = builtin_diff_blobs(&rev, argc, argv, blob);
394                         break;
395                 default:
396                         usage(builtin_diff_usage);
397                 }
398         }
399         else if (blobs)
400                 usage(builtin_diff_usage);
401         else if (ent.nr == 1)
402                 result = builtin_diff_index(&rev, argc, argv);
403         else if (ent.nr == 2)
404                 result = builtin_diff_tree(&rev, argc, argv,
405                                            &ent.objects[0], &ent.objects[1]);
406         else if (ent.objects[0].item->flags & UNINTERESTING) {
407                 /*
408                  * diff A...B where there is at least one merge base
409                  * between A and B.  We have ent.objects[0] ==
410                  * merge-base, ent.objects[ents-2] == A, and
411                  * ent.objects[ents-1] == B.  Show diff between the
412                  * base and B.  Note that we pick one merge base at
413                  * random if there are more than one.
414                  */
415                 result = builtin_diff_tree(&rev, argc, argv,
416                                            &ent.objects[0],
417                                            &ent.objects[ent.nr-1]);
418         } else
419                 result = builtin_diff_combined(&rev, argc, argv,
420                                                ent.objects, ent.nr);
421         result = diff_result_code(&rev.diffopt, result);
422         if (1 < rev.diffopt.skip_stat_unmatch)
423                 refresh_index_quietly();
424         return result;
425 }