Merge branch 'ne/maint-1.6.0-diff-tree-t-r-show-directory'
[git/git.git] / tree-diff.c
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);
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);
81 free(fullname);
82 return 0;
83 }
84
85 /*
86 * Is a tree entry interesting given the pathspec we have?
87 *
88 * Return:
89 * - 2 for "yes, and all subsequent entries will be"
90 * - 1 for yes
91 * - zero for no
92 * - negative for "no, and no subsequent entries will be either"
93 */
94 static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
95 {
96 const char *path;
97 const unsigned char *sha1;
98 unsigned mode;
99 int i;
100 int pathlen;
101 int never_interesting = -1;
102
103 if (!opt->nr_paths)
104 return 1;
105
106 sha1 = tree_entry_extract(desc, &path, &mode);
107
108 pathlen = tree_entry_len(path, sha1);
109
110 for (i = 0; i < opt->nr_paths; i++) {
111 const char *match = opt->paths[i];
112 int matchlen = opt->pathlens[i];
113 int m = -1; /* signals that we haven't called strncmp() */
114
115 if (baselen >= matchlen) {
116 /* If it doesn't match, move along... */
117 if (strncmp(base, match, matchlen))
118 continue;
119
120 /*
121 * If the base is a subdirectory of a path which
122 * was specified, all of them are interesting.
123 */
124 if (!matchlen ||
125 base[matchlen] == '/' ||
126 match[matchlen - 1] == '/')
127 return 2;
128
129 /* Just a random prefix match */
130 continue;
131 }
132
133 /* Does the base match? */
134 if (strncmp(base, match, baselen))
135 continue;
136
137 match += baselen;
138 matchlen -= baselen;
139
140 if (never_interesting) {
141 /*
142 * We have not seen any match that sorts later
143 * than the current path.
144 */
145
146 /*
147 * Does match sort strictly earlier than path
148 * with their common parts?
149 */
150 m = strncmp(match, path,
151 (matchlen < pathlen) ? matchlen : pathlen);
152 if (m < 0)
153 continue;
154
155 /*
156 * If we come here even once, that means there is at
157 * least one pathspec that would sort equal to or
158 * later than the path we are currently looking at.
159 * In other words, if we have never reached this point
160 * after iterating all pathspecs, it means all
161 * pathspecs are either outside of base, or inside the
162 * base but sorts strictly earlier than the current
163 * one. In either case, they will never match the
164 * subsequent entries. In such a case, we initialized
165 * the variable to -1 and that is what will be
166 * returned, allowing the caller to terminate early.
167 */
168 never_interesting = 0;
169 }
170
171 if (pathlen > matchlen)
172 continue;
173
174 if (matchlen > pathlen) {
175 if (match[pathlen] != '/')
176 continue;
177 if (!S_ISDIR(mode))
178 continue;
179 }
180
181 if (m == -1)
182 /*
183 * we cheated and did not do strncmp(), so we do
184 * that here.
185 */
186 m = strncmp(match, path, pathlen);
187
188 /*
189 * If common part matched earlier then it is a hit,
190 * because we rejected the case where path is not a
191 * leading directory and is shorter than match.
192 */
193 if (!m)
194 return 1;
195 }
196 return never_interesting; /* No matches */
197 }
198
199 /* A whole sub-tree went away or appeared */
200 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
201 {
202 int all_interesting = 0;
203 while (desc->size) {
204 int show;
205
206 if (all_interesting)
207 show = 1;
208 else {
209 show = tree_entry_interesting(desc, base, baselen,
210 opt);
211 if (show == 2)
212 all_interesting = 1;
213 }
214 if (show < 0)
215 break;
216 if (show)
217 show_entry(opt, prefix, desc, base, baselen);
218 update_tree_entry(desc);
219 }
220 }
221
222 /* A file entry went away or appeared */
223 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
224 const char *base, int baselen)
225 {
226 unsigned mode;
227 const char *path;
228 const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
229 int pathlen = tree_entry_len(path, sha1);
230
231 if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
232 enum object_type type;
233 char *newbase = malloc_base(base, baselen, path, pathlen);
234 struct tree_desc inner;
235 void *tree;
236 unsigned long size;
237
238 tree = read_sha1_file(sha1, &type, &size);
239 if (!tree || type != OBJ_TREE)
240 die("corrupt tree sha %s", sha1_to_hex(sha1));
241
242 if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
243 newbase[baselen + pathlen] = 0;
244 opt->add_remove(opt, *prefix, mode, sha1, newbase);
245 newbase[baselen + pathlen] = '/';
246 }
247
248 init_tree_desc(&inner, tree, size);
249 show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
250
251 free(tree);
252 free(newbase);
253 } else {
254 char *fullname = malloc_fullname(base, baselen, path, pathlen);
255 opt->add_remove(opt, prefix[0], mode, sha1, fullname);
256 free(fullname);
257 }
258 }
259
260 static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt)
261 {
262 int all_interesting = 0;
263 while (t->size) {
264 int show;
265
266 if (all_interesting)
267 show = 1;
268 else {
269 show = tree_entry_interesting(t, base, baselen, opt);
270 if (show == 2)
271 all_interesting = 1;
272 }
273 if (!show) {
274 update_tree_entry(t);
275 continue;
276 }
277 /* Skip it all? */
278 if (show < 0)
279 t->size = 0;
280 return;
281 }
282 }
283
284 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
285 {
286 int baselen = strlen(base);
287
288 for (;;) {
289 if (DIFF_OPT_TST(opt, QUIET) && DIFF_OPT_TST(opt, HAS_CHANGES))
290 break;
291 if (opt->nr_paths) {
292 skip_uninteresting(t1, base, baselen, opt);
293 skip_uninteresting(t2, base, baselen, opt);
294 }
295 if (!t1->size) {
296 if (!t2->size)
297 break;
298 show_entry(opt, "+", t2, base, baselen);
299 update_tree_entry(t2);
300 continue;
301 }
302 if (!t2->size) {
303 show_entry(opt, "-", t1, base, baselen);
304 update_tree_entry(t1);
305 continue;
306 }
307 switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
308 case -1:
309 update_tree_entry(t1);
310 continue;
311 case 0:
312 update_tree_entry(t1);
313 /* Fallthrough */
314 case 1:
315 update_tree_entry(t2);
316 continue;
317 }
318 die("git diff-tree: internal error");
319 }
320 return 0;
321 }
322
323 /*
324 * Does it look like the resulting diff might be due to a rename?
325 * - single entry
326 * - not a valid previous file
327 */
328 static inline int diff_might_be_rename(void)
329 {
330 return diff_queued_diff.nr == 1 &&
331 !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
332 }
333
334 static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
335 {
336 struct diff_options diff_opts;
337 struct diff_queue_struct *q = &diff_queued_diff;
338 struct diff_filepair *choice;
339 const char *paths[1];
340 int i;
341
342 /* Remove the file creation entry from the diff queue, and remember it */
343 choice = q->queue[0];
344 q->nr = 0;
345
346 diff_setup(&diff_opts);
347 DIFF_OPT_SET(&diff_opts, RECURSIVE);
348 diff_opts.detect_rename = DIFF_DETECT_RENAME;
349 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
350 diff_opts.single_follow = opt->paths[0];
351 diff_opts.break_opt = opt->break_opt;
352 paths[0] = NULL;
353 diff_tree_setup_paths(paths, &diff_opts);
354 if (diff_setup_done(&diff_opts) < 0)
355 die("unable to set up diff options to follow renames");
356 diff_tree(t1, t2, base, &diff_opts);
357 diffcore_std(&diff_opts);
358 diff_tree_release_paths(&diff_opts);
359
360 /* Go through the new set of filepairing, and see if we find a more interesting one */
361 for (i = 0; i < q->nr; i++) {
362 struct diff_filepair *p = q->queue[i];
363
364 /*
365 * Found a source? Not only do we use that for the new
366 * diff_queued_diff, we will also use that as the path in
367 * the future!
368 */
369 if ((p->status == 'R' || p->status == 'C') && !strcmp(p->two->path, opt->paths[0])) {
370 /* Switch the file-pairs around */
371 q->queue[i] = choice;
372 choice = p;
373
374 /* Update the path we use from now on.. */
375 diff_tree_release_paths(opt);
376 opt->paths[0] = xstrdup(p->one->path);
377 diff_tree_setup_paths(opt->paths, opt);
378 break;
379 }
380 }
381
382 /*
383 * Then, discard all the non-relevant file pairs...
384 */
385 for (i = 0; i < q->nr; i++) {
386 struct diff_filepair *p = q->queue[i];
387 diff_free_filepair(p);
388 }
389
390 /*
391 * .. and re-instate the one we want (which might be either the
392 * original one, or the rename/copy we found)
393 */
394 q->queue[0] = choice;
395 q->nr = 1;
396 }
397
398 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
399 {
400 void *tree1, *tree2;
401 struct tree_desc t1, t2;
402 unsigned long size1, size2;
403 int retval;
404
405 tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
406 if (!tree1)
407 die("unable to read source tree (%s)", sha1_to_hex(old));
408 tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
409 if (!tree2)
410 die("unable to read destination tree (%s)", sha1_to_hex(new));
411 init_tree_desc(&t1, tree1, size1);
412 init_tree_desc(&t2, tree2, size2);
413 retval = diff_tree(&t1, &t2, base, opt);
414 if (DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
415 init_tree_desc(&t1, tree1, size1);
416 init_tree_desc(&t2, tree2, size2);
417 try_to_follow_renames(&t1, &t2, base, opt);
418 }
419 free(tree1);
420 free(tree2);
421 return retval;
422 }
423
424 int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
425 {
426 int retval;
427 void *tree;
428 unsigned long size;
429 struct tree_desc empty, real;
430
431 tree = read_object_with_reference(new, tree_type, &size, NULL);
432 if (!tree)
433 die("unable to read root tree (%s)", sha1_to_hex(new));
434 init_tree_desc(&real, tree, size);
435
436 init_tree_desc(&empty, "", 0);
437 retval = diff_tree(&empty, &real, base, opt);
438 free(tree);
439 return retval;
440 }
441
442 static int count_paths(const char **paths)
443 {
444 int i = 0;
445 while (*paths++)
446 i++;
447 return i;
448 }
449
450 void diff_tree_release_paths(struct diff_options *opt)
451 {
452 free(opt->pathlens);
453 }
454
455 void diff_tree_setup_paths(const char **p, struct diff_options *opt)
456 {
457 opt->nr_paths = 0;
458 opt->pathlens = NULL;
459 opt->paths = NULL;
460
461 if (p) {
462 int i;
463
464 opt->paths = p;
465 opt->nr_paths = count_paths(p);
466 if (opt->nr_paths == 0) {
467 opt->pathlens = NULL;
468 return;
469 }
470 opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
471 for (i=0; i < opt->nr_paths; i++)
472 opt->pathlens[i] = strlen(p[i]);
473 }
474 }