git-send-email: Add --thread option
[git/aroben.git] / tree-diff.c
blob26bdbdd2bfea5eab99b9f1c38936efe56f1ab45a
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"
9 static char *malloc_base(const char *base, int baselen, const char *path, int pathlen)
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;
18 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
19 const char *base, int baselen);
21 static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt)
23 unsigned mode1, mode2;
24 const char *path1, *path2;
25 const unsigned char *sha1, *sha2;
26 int cmp, pathlen1, pathlen2;
28 sha1 = tree_entry_extract(t1, &path1, &mode1);
29 sha2 = tree_entry_extract(t2, &path2, &mode2);
31 pathlen1 = tree_entry_len(path1, sha1);
32 pathlen2 = tree_entry_len(path2, sha2);
33 cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
34 if (cmp < 0) {
35 show_entry(opt, "-", t1, base, baselen);
36 return -1;
38 if (cmp > 0) {
39 show_entry(opt, "+", t2, base, baselen);
40 return 1;
42 if (!opt->find_copies_harder && !hashcmp(sha1, sha2) && mode1 == mode2)
43 return 0;
46 * If the filemode has changed to/from a directory from/to a regular
47 * file, we need to consider it a remove and an add.
49 if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
50 show_entry(opt, "-", t1, base, baselen);
51 show_entry(opt, "+", t2, base, baselen);
52 return 0;
55 if (opt->recursive && S_ISDIR(mode1)) {
56 int retval;
57 char *newbase = malloc_base(base, baselen, path1, pathlen1);
58 if (opt->tree_in_recursive)
59 opt->change(opt, mode1, mode2,
60 sha1, sha2, base, path1);
61 retval = diff_tree_sha1(sha1, sha2, newbase, opt);
62 free(newbase);
63 return retval;
66 opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
67 return 0;
71 * Is a tree entry interesting given the pathspec we have?
73 * Return:
74 * - 2 for "yes, and all subsequent entries will be"
75 * - 1 for yes
76 * - zero for no
77 * - negative for "no, and no subsequent entries will be either"
79 static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
81 const char *path;
82 const unsigned char *sha1;
83 unsigned mode;
84 int i;
85 int pathlen;
86 int never_interesting = -1;
88 if (!opt->nr_paths)
89 return 1;
91 sha1 = tree_entry_extract(desc, &path, &mode);
93 pathlen = tree_entry_len(path, sha1);
95 for (i = 0; i < opt->nr_paths; i++) {
96 const char *match = opt->paths[i];
97 int matchlen = opt->pathlens[i];
98 int m = -1; /* signals that we haven't called strncmp() */
100 if (baselen >= matchlen) {
101 /* If it doesn't match, move along... */
102 if (strncmp(base, match, matchlen))
103 continue;
106 * The base is a subdirectory of a path which
107 * was specified, so all of them are interesting.
109 return 2;
112 /* Does the base match? */
113 if (strncmp(base, match, baselen))
114 continue;
116 match += baselen;
117 matchlen -= baselen;
119 if (never_interesting) {
121 * We have not seen any match that sorts later
122 * than the current path.
126 * Does match sort strictly earlier than path
127 * with their common parts?
129 m = strncmp(match, path,
130 (matchlen < pathlen) ? matchlen : pathlen);
131 if (m < 0)
132 continue;
135 * If we come here even once, that means there is at
136 * least one pathspec that would sort equal to or
137 * later than the path we are currently looking at.
138 * In other words, if we have never reached this point
139 * after iterating all pathspecs, it means all
140 * pathspecs are either outside of base, or inside the
141 * base but sorts strictly earlier than the current
142 * one. In either case, they will never match the
143 * subsequent entries. In such a case, we initialized
144 * the variable to -1 and that is what will be
145 * returned, allowing the caller to terminate early.
147 never_interesting = 0;
150 if (pathlen > matchlen)
151 continue;
153 if (matchlen > pathlen) {
154 if (match[pathlen] != '/')
155 continue;
156 if (!S_ISDIR(mode))
157 continue;
160 if (m == -1)
162 * we cheated and did not do strncmp(), so we do
163 * that here.
165 m = strncmp(match, path, pathlen);
168 * If common part matched earlier then it is a hit,
169 * because we rejected the case where path is not a
170 * leading directory and is shorter than match.
172 if (!m)
173 return 1;
175 return never_interesting; /* No matches */
178 /* A whole sub-tree went away or appeared */
179 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
181 int all_interesting = 0;
182 while (desc->size) {
183 int show;
185 if (all_interesting)
186 show = 1;
187 else {
188 show = tree_entry_interesting(desc, base, baselen,
189 opt);
190 if (show == 2)
191 all_interesting = 1;
193 if (show < 0)
194 break;
195 if (show)
196 show_entry(opt, prefix, desc, base, baselen);
197 update_tree_entry(desc);
201 /* A file entry went away or appeared */
202 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
203 const char *base, int baselen)
205 unsigned mode;
206 const char *path;
207 const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
209 if (opt->recursive && S_ISDIR(mode)) {
210 enum object_type type;
211 int pathlen = tree_entry_len(path, sha1);
212 char *newbase = malloc_base(base, baselen, path, pathlen);
213 struct tree_desc inner;
214 void *tree;
215 unsigned long size;
217 tree = read_sha1_file(sha1, &type, &size);
218 if (!tree || type != OBJ_TREE)
219 die("corrupt tree sha %s", sha1_to_hex(sha1));
221 init_tree_desc(&inner, tree, size);
222 show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
224 free(tree);
225 free(newbase);
226 } else {
227 opt->add_remove(opt, prefix[0], mode, sha1, base, path);
231 static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt)
233 int all_interesting = 0;
234 while (t->size) {
235 int show;
237 if (all_interesting)
238 show = 1;
239 else {
240 show = tree_entry_interesting(t, base, baselen, opt);
241 if (show == 2)
242 all_interesting = 1;
244 if (!show) {
245 update_tree_entry(t);
246 continue;
248 /* Skip it all? */
249 if (show < 0)
250 t->size = 0;
251 return;
255 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
257 int baselen = strlen(base);
259 for (;;) {
260 if (opt->quiet && opt->has_changes)
261 break;
262 if (opt->nr_paths) {
263 skip_uninteresting(t1, base, baselen, opt);
264 skip_uninteresting(t2, base, baselen, opt);
266 if (!t1->size) {
267 if (!t2->size)
268 break;
269 show_entry(opt, "+", t2, base, baselen);
270 update_tree_entry(t2);
271 continue;
273 if (!t2->size) {
274 show_entry(opt, "-", t1, base, baselen);
275 update_tree_entry(t1);
276 continue;
278 switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
279 case -1:
280 update_tree_entry(t1);
281 continue;
282 case 0:
283 update_tree_entry(t1);
284 /* Fallthrough */
285 case 1:
286 update_tree_entry(t2);
287 continue;
289 die("git-diff-tree: internal error");
291 return 0;
295 * Does it look like the resulting diff might be due to a rename?
296 * - single entry
297 * - not a valid previous file
299 static inline int diff_might_be_rename(void)
301 return diff_queued_diff.nr == 1 &&
302 !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
305 static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
307 struct diff_options diff_opts;
308 struct diff_queue_struct *q = &diff_queued_diff;
309 struct diff_filepair *choice;
310 const char *paths[1];
311 int i;
313 /* Remove the file creation entry from the diff queue, and remember it */
314 choice = q->queue[0];
315 q->nr = 0;
317 diff_setup(&diff_opts);
318 diff_opts.recursive = 1;
319 diff_opts.detect_rename = DIFF_DETECT_RENAME;
320 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
321 diff_opts.single_follow = opt->paths[0];
322 paths[0] = NULL;
323 diff_tree_setup_paths(paths, &diff_opts);
324 if (diff_setup_done(&diff_opts) < 0)
325 die("unable to set up diff options to follow renames");
326 diff_tree(t1, t2, base, &diff_opts);
327 diffcore_std(&diff_opts);
329 /* Go through the new set of filepairing, and see if we find a more interesting one */
330 for (i = 0; i < q->nr; i++) {
331 struct diff_filepair *p = q->queue[i];
334 * Found a source? Not only do we use that for the new
335 * diff_queued_diff, we will also use that as the path in
336 * the future!
338 if ((p->status == 'R' || p->status == 'C') && !strcmp(p->two->path, opt->paths[0])) {
339 /* Switch the file-pairs around */
340 q->queue[i] = choice;
341 choice = p;
343 /* Update the path we use from now on.. */
344 opt->paths[0] = xstrdup(p->one->path);
345 diff_tree_setup_paths(opt->paths, opt);
346 break;
351 * Then, discard all the non-relevane file pairs...
353 for (i = 0; i < q->nr; i++) {
354 struct diff_filepair *p = q->queue[i];
355 diff_free_filepair(p);
359 * .. and re-instate the one we want (which might be either the
360 * original one, or the rename/copy we found)
362 q->queue[0] = choice;
363 q->nr = 1;
366 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
368 void *tree1, *tree2;
369 struct tree_desc t1, t2;
370 unsigned long size1, size2;
371 int retval;
373 tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
374 if (!tree1)
375 die("unable to read source tree (%s)", sha1_to_hex(old));
376 tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
377 if (!tree2)
378 die("unable to read destination tree (%s)", sha1_to_hex(new));
379 init_tree_desc(&t1, tree1, size1);
380 init_tree_desc(&t2, tree2, size2);
381 retval = diff_tree(&t1, &t2, base, opt);
382 if (opt->follow_renames && diff_might_be_rename()) {
383 init_tree_desc(&t1, tree1, size1);
384 init_tree_desc(&t2, tree2, size2);
385 try_to_follow_renames(&t1, &t2, base, opt);
387 free(tree1);
388 free(tree2);
389 return retval;
392 int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
394 int retval;
395 void *tree;
396 unsigned long size;
397 struct tree_desc empty, real;
399 tree = read_object_with_reference(new, tree_type, &size, NULL);
400 if (!tree)
401 die("unable to read root tree (%s)", sha1_to_hex(new));
402 init_tree_desc(&real, tree, size);
404 init_tree_desc(&empty, "", 0);
405 retval = diff_tree(&empty, &real, base, opt);
406 free(tree);
407 return retval;
410 static int count_paths(const char **paths)
412 int i = 0;
413 while (*paths++)
414 i++;
415 return i;
418 void diff_tree_release_paths(struct diff_options *opt)
420 free(opt->pathlens);
423 void diff_tree_setup_paths(const char **p, struct diff_options *opt)
425 opt->nr_paths = 0;
426 opt->pathlens = NULL;
427 opt->paths = NULL;
429 if (p) {
430 int i;
432 opt->paths = p;
433 opt->nr_paths = count_paths(p);
434 if (opt->nr_paths == 0) {
435 opt->pathlens = NULL;
436 return;
438 opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
439 for (i=0; i < opt->nr_paths; i++)
440 opt->pathlens[i] = strlen(p[i]);