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Commit | Line | Data |
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1 | /* | |
2 | * Helper functions for tree diff generation | |
3 | */ | |
4 | #include "cache.h" | |
5 | #include "diff.h" | |
6 | #include "diffcore.h" | |
7 | #include "tree.h" | |
8 | ||
9 | static char *malloc_base(const char *base, int baselen, const char *path, int pathlen) | |
10 | { | |
11 | char *newbase = xmalloc(baselen + pathlen + 2); | |
12 | memcpy(newbase, base, baselen); | |
13 | memcpy(newbase + baselen, path, pathlen); | |
14 | memcpy(newbase + baselen + pathlen, "/", 2); | |
15 | return newbase; | |
16 | } | |
17 | ||
18 | static char *malloc_fullname(const char *base, int baselen, const char *path, int pathlen) | |
19 | { | |
20 | char *fullname = xmalloc(baselen + pathlen + 1); | |
21 | memcpy(fullname, base, baselen); | |
22 | memcpy(fullname + baselen, path, pathlen); | |
23 | fullname[baselen + pathlen] = 0; | |
24 | return fullname; | |
25 | } | |
26 | ||
27 | static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, | |
28 | const char *base, int baselen); | |
29 | ||
30 | static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt) | |
31 | { | |
32 | unsigned mode1, mode2; | |
33 | const char *path1, *path2; | |
34 | const unsigned char *sha1, *sha2; | |
35 | int cmp, pathlen1, pathlen2; | |
36 | char *fullname; | |
37 | ||
38 | sha1 = tree_entry_extract(t1, &path1, &mode1); | |
39 | sha2 = tree_entry_extract(t2, &path2, &mode2); | |
40 | ||
41 | pathlen1 = tree_entry_len(path1, sha1); | |
42 | pathlen2 = tree_entry_len(path2, sha2); | |
43 | cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2); | |
44 | if (cmp < 0) { | |
45 | show_entry(opt, "-", t1, base, baselen); | |
46 | return -1; | |
47 | } | |
48 | if (cmp > 0) { | |
49 | show_entry(opt, "+", t2, base, baselen); | |
50 | return 1; | |
51 | } | |
52 | if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2) | |
53 | return 0; | |
54 | ||
55 | /* | |
56 | * If the filemode has changed to/from a directory from/to a regular | |
57 | * file, we need to consider it a remove and an add. | |
58 | */ | |
59 | if (S_ISDIR(mode1) != S_ISDIR(mode2)) { | |
60 | show_entry(opt, "-", t1, base, baselen); | |
61 | show_entry(opt, "+", t2, base, baselen); | |
62 | return 0; | |
63 | } | |
64 | ||
65 | if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) { | |
66 | int retval; | |
67 | char *newbase = malloc_base(base, baselen, path1, pathlen1); | |
68 | if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) { | |
69 | newbase[baselen + pathlen1] = 0; | |
70 | opt->change(opt, mode1, mode2, | |
71 | sha1, sha2, newbase, 0, 0); | |
72 | newbase[baselen + pathlen1] = '/'; | |
73 | } | |
74 | retval = diff_tree_sha1(sha1, sha2, newbase, opt); | |
75 | free(newbase); | |
76 | return retval; | |
77 | } | |
78 | ||
79 | fullname = malloc_fullname(base, baselen, path1, pathlen1); | |
80 | opt->change(opt, mode1, mode2, sha1, sha2, fullname, 0, 0); | |
81 | free(fullname); | |
82 | return 0; | |
83 | } | |
84 | ||
85 | /* | |
86 | * Is a tree entry interesting given the pathspec we have? | |
87 | * | |
88 | * Pre-condition: baselen == 0 || base[baselen-1] == '/' | |
89 | * | |
90 | * Return: | |
91 | * - 2 for "yes, and all subsequent entries will be" | |
92 | * - 1 for yes | |
93 | * - zero for no | |
94 | * - negative for "no, and no subsequent entries will be either" | |
95 | */ | |
96 | static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt) | |
97 | { | |
98 | const char *path; | |
99 | const unsigned char *sha1; | |
100 | unsigned mode; | |
101 | int i; | |
102 | int pathlen; | |
103 | int never_interesting = -1; | |
104 | ||
105 | if (!opt->nr_paths) | |
106 | return 2; | |
107 | ||
108 | sha1 = tree_entry_extract(desc, &path, &mode); | |
109 | ||
110 | pathlen = tree_entry_len(path, sha1); | |
111 | ||
112 | for (i = 0; i < opt->nr_paths; i++) { | |
113 | const char *match = opt->paths[i]; | |
114 | int matchlen = opt->pathlens[i]; | |
115 | int m = -1; /* signals that we haven't called strncmp() */ | |
116 | ||
117 | if (baselen >= matchlen) { | |
118 | /* If it doesn't match, move along... */ | |
119 | if (strncmp(base, match, matchlen)) | |
120 | continue; | |
121 | ||
122 | /* | |
123 | * If the base is a subdirectory of a path which | |
124 | * was specified, all of them are interesting. | |
125 | */ | |
126 | if (!matchlen || | |
127 | base[matchlen] == '/' || | |
128 | match[matchlen - 1] == '/') | |
129 | return 2; | |
130 | ||
131 | /* Just a random prefix match */ | |
132 | continue; | |
133 | } | |
134 | ||
135 | /* Does the base match? */ | |
136 | if (strncmp(base, match, baselen)) | |
137 | continue; | |
138 | ||
139 | match += baselen; | |
140 | matchlen -= baselen; | |
141 | ||
142 | if (never_interesting) { | |
143 | /* | |
144 | * We have not seen any match that sorts later | |
145 | * than the current path. | |
146 | */ | |
147 | ||
148 | /* | |
149 | * Does match sort strictly earlier than path | |
150 | * with their common parts? | |
151 | */ | |
152 | m = strncmp(match, path, | |
153 | (matchlen < pathlen) ? matchlen : pathlen); | |
154 | if (m < 0) | |
155 | continue; | |
156 | ||
157 | /* | |
158 | * If we come here even once, that means there is at | |
159 | * least one pathspec that would sort equal to or | |
160 | * later than the path we are currently looking at. | |
161 | * In other words, if we have never reached this point | |
162 | * after iterating all pathspecs, it means all | |
163 | * pathspecs are either outside of base, or inside the | |
164 | * base but sorts strictly earlier than the current | |
165 | * one. In either case, they will never match the | |
166 | * subsequent entries. In such a case, we initialized | |
167 | * the variable to -1 and that is what will be | |
168 | * returned, allowing the caller to terminate early. | |
169 | */ | |
170 | never_interesting = 0; | |
171 | } | |
172 | ||
173 | if (pathlen > matchlen) | |
174 | continue; | |
175 | ||
176 | if (matchlen > pathlen) { | |
177 | if (match[pathlen] != '/') | |
178 | continue; | |
179 | if (!S_ISDIR(mode)) | |
180 | continue; | |
181 | } | |
182 | ||
183 | if (m == -1) | |
184 | /* | |
185 | * we cheated and did not do strncmp(), so we do | |
186 | * that here. | |
187 | */ | |
188 | m = strncmp(match, path, pathlen); | |
189 | ||
190 | /* | |
191 | * If common part matched earlier then it is a hit, | |
192 | * because we rejected the case where path is not a | |
193 | * leading directory and is shorter than match. | |
194 | */ | |
195 | if (!m) | |
196 | return 1; | |
197 | } | |
198 | return never_interesting; /* No matches */ | |
199 | } | |
200 | ||
201 | /* A whole sub-tree went away or appeared */ | |
202 | static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen) | |
203 | { | |
204 | int all_interesting = 0; | |
205 | while (desc->size) { | |
206 | int show; | |
207 | ||
208 | if (all_interesting) | |
209 | show = 1; | |
210 | else { | |
211 | show = tree_entry_interesting(desc, base, baselen, | |
212 | opt); | |
213 | if (show == 2) | |
214 | all_interesting = 1; | |
215 | } | |
216 | if (show < 0) | |
217 | break; | |
218 | if (show) | |
219 | show_entry(opt, prefix, desc, base, baselen); | |
220 | update_tree_entry(desc); | |
221 | } | |
222 | } | |
223 | ||
224 | /* A file entry went away or appeared */ | |
225 | static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, | |
226 | const char *base, int baselen) | |
227 | { | |
228 | unsigned mode; | |
229 | const char *path; | |
230 | const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode); | |
231 | int pathlen = tree_entry_len(path, sha1); | |
232 | ||
233 | if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) { | |
234 | enum object_type type; | |
235 | char *newbase = malloc_base(base, baselen, path, pathlen); | |
236 | struct tree_desc inner; | |
237 | void *tree; | |
238 | unsigned long size; | |
239 | ||
240 | tree = read_sha1_file(sha1, &type, &size); | |
241 | if (!tree || type != OBJ_TREE) | |
242 | die("corrupt tree sha %s", sha1_to_hex(sha1)); | |
243 | ||
244 | if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) { | |
245 | newbase[baselen + pathlen] = 0; | |
246 | opt->add_remove(opt, *prefix, mode, sha1, newbase, 0); | |
247 | newbase[baselen + pathlen] = '/'; | |
248 | } | |
249 | ||
250 | init_tree_desc(&inner, tree, size); | |
251 | show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen); | |
252 | ||
253 | free(tree); | |
254 | free(newbase); | |
255 | } else { | |
256 | char *fullname = malloc_fullname(base, baselen, path, pathlen); | |
257 | opt->add_remove(opt, prefix[0], mode, sha1, fullname, 0); | |
258 | free(fullname); | |
259 | } | |
260 | } | |
261 | ||
262 | static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt, int *all_interesting) | |
263 | { | |
264 | while (t->size) { | |
265 | int show = tree_entry_interesting(t, base, baselen, opt); | |
266 | if (show == 2) | |
267 | *all_interesting = 1; | |
268 | if (!show) { | |
269 | update_tree_entry(t); | |
270 | continue; | |
271 | } | |
272 | /* Skip it all? */ | |
273 | if (show < 0) | |
274 | t->size = 0; | |
275 | return; | |
276 | } | |
277 | } | |
278 | ||
279 | int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt) | |
280 | { | |
281 | int baselen = strlen(base); | |
282 | int all_t1_interesting = 0; | |
283 | int all_t2_interesting = 0; | |
284 | ||
285 | for (;;) { | |
286 | if (DIFF_OPT_TST(opt, QUICK) && | |
287 | DIFF_OPT_TST(opt, HAS_CHANGES)) | |
288 | break; | |
289 | if (opt->nr_paths) { | |
290 | if (!all_t1_interesting) | |
291 | skip_uninteresting(t1, base, baselen, opt, | |
292 | &all_t1_interesting); | |
293 | if (!all_t2_interesting) | |
294 | skip_uninteresting(t2, base, baselen, opt, | |
295 | &all_t2_interesting); | |
296 | } | |
297 | if (!t1->size) { | |
298 | if (!t2->size) | |
299 | break; | |
300 | show_entry(opt, "+", t2, base, baselen); | |
301 | update_tree_entry(t2); | |
302 | continue; | |
303 | } | |
304 | if (!t2->size) { | |
305 | show_entry(opt, "-", t1, base, baselen); | |
306 | update_tree_entry(t1); | |
307 | continue; | |
308 | } | |
309 | switch (compare_tree_entry(t1, t2, base, baselen, opt)) { | |
310 | case -1: | |
311 | update_tree_entry(t1); | |
312 | continue; | |
313 | case 0: | |
314 | update_tree_entry(t1); | |
315 | /* Fallthrough */ | |
316 | case 1: | |
317 | update_tree_entry(t2); | |
318 | continue; | |
319 | } | |
320 | die("git diff-tree: internal error"); | |
321 | } | |
322 | return 0; | |
323 | } | |
324 | ||
325 | /* | |
326 | * Does it look like the resulting diff might be due to a rename? | |
327 | * - single entry | |
328 | * - not a valid previous file | |
329 | */ | |
330 | static inline int diff_might_be_rename(void) | |
331 | { | |
332 | return diff_queued_diff.nr == 1 && | |
333 | !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one); | |
334 | } | |
335 | ||
336 | static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt) | |
337 | { | |
338 | struct diff_options diff_opts; | |
339 | struct diff_queue_struct *q = &diff_queued_diff; | |
340 | struct diff_filepair *choice; | |
341 | const char *paths[1]; | |
342 | int i; | |
343 | ||
344 | /* Remove the file creation entry from the diff queue, and remember it */ | |
345 | choice = q->queue[0]; | |
346 | q->nr = 0; | |
347 | ||
348 | diff_setup(&diff_opts); | |
349 | DIFF_OPT_SET(&diff_opts, RECURSIVE); | |
350 | DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER); | |
351 | diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; | |
352 | diff_opts.single_follow = opt->paths[0]; | |
353 | diff_opts.break_opt = opt->break_opt; | |
354 | paths[0] = NULL; | |
355 | diff_tree_setup_paths(paths, &diff_opts); | |
356 | if (diff_setup_done(&diff_opts) < 0) | |
357 | die("unable to set up diff options to follow renames"); | |
358 | diff_tree(t1, t2, base, &diff_opts); | |
359 | diffcore_std(&diff_opts); | |
360 | diff_tree_release_paths(&diff_opts); | |
361 | ||
362 | /* Go through the new set of filepairing, and see if we find a more interesting one */ | |
363 | opt->found_follow = 0; | |
364 | for (i = 0; i < q->nr; i++) { | |
365 | struct diff_filepair *p = q->queue[i]; | |
366 | ||
367 | /* | |
368 | * Found a source? Not only do we use that for the new | |
369 | * diff_queued_diff, we will also use that as the path in | |
370 | * the future! | |
371 | */ | |
372 | if ((p->status == 'R' || p->status == 'C') && !strcmp(p->two->path, opt->paths[0])) { | |
373 | /* Switch the file-pairs around */ | |
374 | q->queue[i] = choice; | |
375 | choice = p; | |
376 | ||
377 | /* Update the path we use from now on.. */ | |
378 | diff_tree_release_paths(opt); | |
379 | opt->paths[0] = xstrdup(p->one->path); | |
380 | diff_tree_setup_paths(opt->paths, opt); | |
381 | ||
382 | /* | |
383 | * The caller expects us to return a set of vanilla | |
384 | * filepairs to let a later call to diffcore_std() | |
385 | * it makes to sort the renames out (among other | |
386 | * things), but we already have found renames | |
387 | * ourselves; signal diffcore_std() not to muck with | |
388 | * rename information. | |
389 | */ | |
390 | opt->found_follow = 1; | |
391 | break; | |
392 | } | |
393 | } | |
394 | ||
395 | /* | |
396 | * Then, discard all the non-relevant file pairs... | |
397 | */ | |
398 | for (i = 0; i < q->nr; i++) { | |
399 | struct diff_filepair *p = q->queue[i]; | |
400 | diff_free_filepair(p); | |
401 | } | |
402 | ||
403 | /* | |
404 | * .. and re-instate the one we want (which might be either the | |
405 | * original one, or the rename/copy we found) | |
406 | */ | |
407 | q->queue[0] = choice; | |
408 | q->nr = 1; | |
409 | } | |
410 | ||
411 | int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt) | |
412 | { | |
413 | void *tree1, *tree2; | |
414 | struct tree_desc t1, t2; | |
415 | unsigned long size1, size2; | |
416 | int retval; | |
417 | ||
418 | tree1 = read_object_with_reference(old, tree_type, &size1, NULL); | |
419 | if (!tree1) | |
420 | die("unable to read source tree (%s)", sha1_to_hex(old)); | |
421 | tree2 = read_object_with_reference(new, tree_type, &size2, NULL); | |
422 | if (!tree2) | |
423 | die("unable to read destination tree (%s)", sha1_to_hex(new)); | |
424 | init_tree_desc(&t1, tree1, size1); | |
425 | init_tree_desc(&t2, tree2, size2); | |
426 | retval = diff_tree(&t1, &t2, base, opt); | |
427 | if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) { | |
428 | init_tree_desc(&t1, tree1, size1); | |
429 | init_tree_desc(&t2, tree2, size2); | |
430 | try_to_follow_renames(&t1, &t2, base, opt); | |
431 | } | |
432 | free(tree1); | |
433 | free(tree2); | |
434 | return retval; | |
435 | } | |
436 | ||
437 | int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt) | |
438 | { | |
439 | int retval; | |
440 | void *tree; | |
441 | unsigned long size; | |
442 | struct tree_desc empty, real; | |
443 | ||
444 | tree = read_object_with_reference(new, tree_type, &size, NULL); | |
445 | if (!tree) | |
446 | die("unable to read root tree (%s)", sha1_to_hex(new)); | |
447 | init_tree_desc(&real, tree, size); | |
448 | ||
449 | init_tree_desc(&empty, "", 0); | |
450 | retval = diff_tree(&empty, &real, base, opt); | |
451 | free(tree); | |
452 | return retval; | |
453 | } | |
454 | ||
455 | static int count_paths(const char **paths) | |
456 | { | |
457 | int i = 0; | |
458 | while (*paths++) | |
459 | i++; | |
460 | return i; | |
461 | } | |
462 | ||
463 | void diff_tree_release_paths(struct diff_options *opt) | |
464 | { | |
465 | free(opt->pathlens); | |
466 | } | |
467 | ||
468 | void diff_tree_setup_paths(const char **p, struct diff_options *opt) | |
469 | { | |
470 | opt->nr_paths = 0; | |
471 | opt->pathlens = NULL; | |
472 | opt->paths = NULL; | |
473 | ||
474 | if (p) { | |
475 | int i; | |
476 | ||
477 | opt->paths = p; | |
478 | opt->nr_paths = count_paths(p); | |
479 | if (opt->nr_paths == 0) { | |
480 | opt->pathlens = NULL; | |
481 | return; | |
482 | } | |
483 | opt->pathlens = xmalloc(opt->nr_paths * sizeof(int)); | |
484 | for (i=0; i < opt->nr_paths; i++) | |
485 | opt->pathlens[i] = strlen(p[i]); | |
486 | } | |
487 | } |