diff: do not use null sha1 as a sentinel value
[git/git.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 /* Default to let external and textconv be used */
293 DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
294 DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
295
296 if (nongit)
297 die(_("Not a git repository"));
298 argc = setup_revisions(argc, argv, &rev, NULL);
299 if (!rev.diffopt.output_format) {
300 rev.diffopt.output_format = DIFF_FORMAT_PATCH;
301 if (diff_setup_done(&rev.diffopt) < 0)
302 die(_("diff_setup_done failed"));
303 }
304
305 DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
306
307 /*
308 * If the user asked for our exit code then don't start a
309 * pager or we would end up reporting its exit code instead.
310 */
311 if (!DIFF_OPT_TST(&rev.diffopt, EXIT_WITH_STATUS) &&
312 check_pager_config("diff") != 0)
313 setup_pager();
314
315 /*
316 * Do we have --cached and not have a pending object, then
317 * default to HEAD by hand. Eek.
318 */
319 if (!rev.pending.nr) {
320 int i;
321 for (i = 1; i < argc; i++) {
322 const char *arg = argv[i];
323 if (!strcmp(arg, "--"))
324 break;
325 else if (!strcmp(arg, "--cached") ||
326 !strcmp(arg, "--staged")) {
327 add_head_to_pending(&rev);
328 if (!rev.pending.nr) {
329 struct tree *tree;
330 tree = lookup_tree((const unsigned char*)EMPTY_TREE_SHA1_BIN);
331 add_pending_object(&rev, &tree->object, "HEAD");
332 }
333 break;
334 }
335 }
336 }
337
338 for (i = 0; i < rev.pending.nr; i++) {
339 struct object_array_entry *list = rev.pending.objects+i;
340 struct object *obj = list->item;
341 const char *name = list->name;
342 int flags = (obj->flags & UNINTERESTING);
343 if (!obj->parsed)
344 obj = parse_object(obj->sha1);
345 obj = deref_tag(obj, NULL, 0);
346 if (!obj)
347 die(_("invalid object '%s' given."), name);
348 if (obj->type == OBJ_COMMIT)
349 obj = &((struct commit *)obj)->tree->object;
350 if (obj->type == OBJ_TREE) {
351 if (ARRAY_SIZE(ent) <= ents)
352 die(_("more than %d trees given: '%s'"),
353 (int) ARRAY_SIZE(ent), name);
354 obj->flags |= flags;
355 ent[ents].item = obj;
356 ent[ents].name = name;
357 ents++;
358 continue;
359 }
360 if (obj->type == OBJ_BLOB) {
361 if (2 <= blobs)
362 die(_("more than two blobs given: '%s'"), name);
363 hashcpy(blob[blobs].sha1, obj->sha1);
364 blob[blobs].name = name;
365 blob[blobs].mode = list->mode;
366 blobs++;
367 continue;
368
369 }
370 die(_("unhandled object '%s' given."), name);
371 }
372 if (rev.prune_data.nr) {
373 if (!path)
374 path = rev.prune_data.items[0].match;
375 paths += rev.prune_data.nr;
376 }
377
378 /*
379 * Now, do the arguments look reasonable?
380 */
381 if (!ents) {
382 switch (blobs) {
383 case 0:
384 result = builtin_diff_files(&rev, argc, argv);
385 break;
386 case 1:
387 if (paths != 1)
388 usage(builtin_diff_usage);
389 result = builtin_diff_b_f(&rev, argc, argv, blob, path);
390 break;
391 case 2:
392 if (paths)
393 usage(builtin_diff_usage);
394 result = builtin_diff_blobs(&rev, argc, argv, blob);
395 break;
396 default:
397 usage(builtin_diff_usage);
398 }
399 }
400 else if (blobs)
401 usage(builtin_diff_usage);
402 else if (ents == 1)
403 result = builtin_diff_index(&rev, argc, argv);
404 else if (ents == 2)
405 result = builtin_diff_tree(&rev, argc, argv, ent);
406 else if (ent[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[0] == merge-base,
410 * ent[ents-2] == A, and ent[ents-1] == B. Show diff
411 * between the base and B. Note that we pick one
412 * merge base at random if there are more than one.
413 */
414 ent[1] = ent[ents-1];
415 result = builtin_diff_tree(&rev, argc, argv, ent);
416 } else
417 result = builtin_diff_combined(&rev, argc, argv,
418 ent, ents);
419 result = diff_result_code(&rev.diffopt, result);
420 if (1 < rev.diffopt.skip_stat_unmatch)
421 refresh_index_quietly();
422 return result;
423 }