git-send-email: Add --thread option
[git/aroben.git] / diffcore-rename.c
blob79c984c9cf5489d22f359b7a2ad3464ffc271c35
1 /*
2 * Copyright (C) 2005 Junio C Hamano
3 */
4 #include "cache.h"
5 #include "diff.h"
6 #include "diffcore.h"
8 /* Table of rename/copy destinations */
10 static struct diff_rename_dst {
11 struct diff_filespec *two;
12 struct diff_filepair *pair;
13 } *rename_dst;
14 static int rename_dst_nr, rename_dst_alloc;
16 static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
17 int insert_ok)
19 int first, last;
21 first = 0;
22 last = rename_dst_nr;
23 while (last > first) {
24 int next = (last + first) >> 1;
25 struct diff_rename_dst *dst = &(rename_dst[next]);
26 int cmp = strcmp(two->path, dst->two->path);
27 if (!cmp)
28 return dst;
29 if (cmp < 0) {
30 last = next;
31 continue;
33 first = next+1;
35 /* not found */
36 if (!insert_ok)
37 return NULL;
38 /* insert to make it at "first" */
39 if (rename_dst_alloc <= rename_dst_nr) {
40 rename_dst_alloc = alloc_nr(rename_dst_alloc);
41 rename_dst = xrealloc(rename_dst,
42 rename_dst_alloc * sizeof(*rename_dst));
44 rename_dst_nr++;
45 if (first < rename_dst_nr)
46 memmove(rename_dst + first + 1, rename_dst + first,
47 (rename_dst_nr - first - 1) * sizeof(*rename_dst));
48 rename_dst[first].two = alloc_filespec(two->path);
49 fill_filespec(rename_dst[first].two, two->sha1, two->mode);
50 rename_dst[first].pair = NULL;
51 return &(rename_dst[first]);
54 /* Table of rename/copy src files */
55 static struct diff_rename_src {
56 struct diff_filespec *one;
57 unsigned short score; /* to remember the break score */
58 unsigned src_path_left : 1;
59 } *rename_src;
60 static int rename_src_nr, rename_src_alloc;
62 static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
63 int src_path_left,
64 unsigned short score)
66 int first, last;
68 first = 0;
69 last = rename_src_nr;
70 while (last > first) {
71 int next = (last + first) >> 1;
72 struct diff_rename_src *src = &(rename_src[next]);
73 int cmp = strcmp(one->path, src->one->path);
74 if (!cmp)
75 return src;
76 if (cmp < 0) {
77 last = next;
78 continue;
80 first = next+1;
83 /* insert to make it at "first" */
84 if (rename_src_alloc <= rename_src_nr) {
85 rename_src_alloc = alloc_nr(rename_src_alloc);
86 rename_src = xrealloc(rename_src,
87 rename_src_alloc * sizeof(*rename_src));
89 rename_src_nr++;
90 if (first < rename_src_nr)
91 memmove(rename_src + first + 1, rename_src + first,
92 (rename_src_nr - first - 1) * sizeof(*rename_src));
93 rename_src[first].one = one;
94 rename_src[first].score = score;
95 rename_src[first].src_path_left = src_path_left;
96 return &(rename_src[first]);
99 static int is_exact_match(struct diff_filespec *src,
100 struct diff_filespec *dst,
101 int contents_too)
103 if (src->sha1_valid && dst->sha1_valid &&
104 !hashcmp(src->sha1, dst->sha1))
105 return 1;
106 if (!contents_too)
107 return 0;
108 if (diff_populate_filespec(src, 1) || diff_populate_filespec(dst, 1))
109 return 0;
110 if (src->size != dst->size)
111 return 0;
112 if (src->sha1_valid && dst->sha1_valid)
113 return !hashcmp(src->sha1, dst->sha1);
114 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
115 return 0;
116 if (src->size == dst->size &&
117 !memcmp(src->data, dst->data, src->size))
118 return 1;
119 return 0;
122 static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
124 int src_len = strlen(src->path), dst_len = strlen(dst->path);
125 while (src_len && dst_len) {
126 char c1 = src->path[--src_len];
127 char c2 = dst->path[--dst_len];
128 if (c1 != c2)
129 return 0;
130 if (c1 == '/')
131 return 1;
133 return (!src_len || src->path[src_len - 1] == '/') &&
134 (!dst_len || dst->path[dst_len - 1] == '/');
137 struct diff_score {
138 int src; /* index in rename_src */
139 int dst; /* index in rename_dst */
140 int score;
143 static int estimate_similarity(struct diff_filespec *src,
144 struct diff_filespec *dst,
145 int minimum_score)
147 /* src points at a file that existed in the original tree (or
148 * optionally a file in the destination tree) and dst points
149 * at a newly created file. They may be quite similar, in which
150 * case we want to say src is renamed to dst or src is copied into
151 * dst, and then some edit has been applied to dst.
153 * Compare them and return how similar they are, representing
154 * the score as an integer between 0 and MAX_SCORE.
156 * When there is an exact match, it is considered a better
157 * match than anything else; the destination does not even
158 * call into this function in that case.
160 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
161 unsigned long delta_limit;
162 int score;
164 /* We deal only with regular files. Symlink renames are handled
165 * only when they are exact matches --- in other words, no edits
166 * after renaming.
168 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
169 return 0;
171 max_size = ((src->size > dst->size) ? src->size : dst->size);
172 base_size = ((src->size < dst->size) ? src->size : dst->size);
173 delta_size = max_size - base_size;
175 /* We would not consider edits that change the file size so
176 * drastically. delta_size must be smaller than
177 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
179 * Note that base_size == 0 case is handled here already
180 * and the final score computation below would not have a
181 * divide-by-zero issue.
183 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
184 return 0;
186 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
187 return 0; /* error but caught downstream */
190 delta_limit = (unsigned long)
191 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
192 if (diffcore_count_changes(src->data, src->size,
193 dst->data, dst->size,
194 &src->cnt_data, &dst->cnt_data,
195 delta_limit,
196 &src_copied, &literal_added))
197 return 0;
199 /* How similar are they?
200 * what percentage of material in dst are from source?
202 if (!dst->size)
203 score = 0; /* should not happen */
204 else {
205 score = (int)(src_copied * MAX_SCORE / max_size);
206 if (basename_same(src, dst))
207 score++;
209 return score;
212 static void record_rename_pair(int dst_index, int src_index, int score)
214 struct diff_filespec *one, *two, *src, *dst;
215 struct diff_filepair *dp;
217 if (rename_dst[dst_index].pair)
218 die("internal error: dst already matched.");
220 src = rename_src[src_index].one;
221 one = alloc_filespec(src->path);
222 fill_filespec(one, src->sha1, src->mode);
224 dst = rename_dst[dst_index].two;
225 two = alloc_filespec(dst->path);
226 fill_filespec(two, dst->sha1, dst->mode);
228 dp = diff_queue(NULL, one, two);
229 dp->renamed_pair = 1;
230 if (!strcmp(src->path, dst->path))
231 dp->score = rename_src[src_index].score;
232 else
233 dp->score = score;
234 dp->source_stays = rename_src[src_index].src_path_left;
235 rename_dst[dst_index].pair = dp;
239 * We sort the rename similarity matrix with the score, in descending
240 * order (the most similar first).
242 static int score_compare(const void *a_, const void *b_)
244 const struct diff_score *a = a_, *b = b_;
245 return b->score - a->score;
248 static int compute_stays(struct diff_queue_struct *q,
249 struct diff_filespec *one)
251 int i;
252 for (i = 0; i < q->nr; i++) {
253 struct diff_filepair *p = q->queue[i];
254 if (strcmp(one->path, p->two->path))
255 continue;
256 if (DIFF_PAIR_RENAME(p)) {
257 return 0; /* something else is renamed into this */
260 return 1;
263 void diffcore_rename(struct diff_options *options)
265 int detect_rename = options->detect_rename;
266 int minimum_score = options->rename_score;
267 int rename_limit = options->rename_limit;
268 struct diff_queue_struct *q = &diff_queued_diff;
269 struct diff_queue_struct outq;
270 struct diff_score *mx;
271 int i, j, rename_count, contents_too;
272 int num_create, num_src, dst_cnt;
274 if (!minimum_score)
275 minimum_score = DEFAULT_RENAME_SCORE;
276 rename_count = 0;
278 for (i = 0; i < q->nr; i++) {
279 struct diff_filepair *p = q->queue[i];
280 if (!DIFF_FILE_VALID(p->one)) {
281 if (!DIFF_FILE_VALID(p->two))
282 continue; /* unmerged */
283 else if (options->single_follow &&
284 strcmp(options->single_follow, p->two->path))
285 continue; /* not interested */
286 else
287 locate_rename_dst(p->two, 1);
289 else if (!DIFF_FILE_VALID(p->two)) {
290 /* If the source is a broken "delete", and
291 * they did not really want to get broken,
292 * that means the source actually stays.
294 int stays = (p->broken_pair && !p->score);
295 register_rename_src(p->one, stays, p->score);
297 else if (detect_rename == DIFF_DETECT_COPY)
298 register_rename_src(p->one, 1, p->score);
300 if (rename_dst_nr == 0 || rename_src_nr == 0 ||
301 (0 < rename_limit && rename_limit < rename_dst_nr))
302 goto cleanup; /* nothing to do */
304 /* We really want to cull the candidates list early
305 * with cheap tests in order to avoid doing deltas.
306 * The first round matches up the up-to-date entries,
307 * and then during the second round we try to match
308 * cache-dirty entries as well.
310 for (contents_too = 0; contents_too < 2; contents_too++) {
311 for (i = 0; i < rename_dst_nr; i++) {
312 struct diff_filespec *two = rename_dst[i].two;
313 if (rename_dst[i].pair)
314 continue; /* dealt with an earlier round */
315 for (j = 0; j < rename_src_nr; j++) {
316 int k;
317 struct diff_filespec *one = rename_src[j].one;
318 if (!is_exact_match(one, two, contents_too))
319 continue;
321 /* see if there is a basename match, too */
322 for (k = j; k < rename_src_nr; k++) {
323 one = rename_src[k].one;
324 if (basename_same(one, two) &&
325 is_exact_match(one, two,
326 contents_too)) {
327 j = k;
328 break;
332 record_rename_pair(i, j, (int)MAX_SCORE);
333 rename_count++;
334 break; /* we are done with this entry */
339 /* Have we run out the created file pool? If so we can avoid
340 * doing the delta matrix altogether.
342 if (rename_count == rename_dst_nr)
343 goto cleanup;
345 if (minimum_score == MAX_SCORE)
346 goto cleanup;
348 num_create = (rename_dst_nr - rename_count);
349 num_src = rename_src_nr;
350 mx = xmalloc(sizeof(*mx) * num_create * num_src);
351 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
352 int base = dst_cnt * num_src;
353 struct diff_filespec *two = rename_dst[i].two;
354 if (rename_dst[i].pair)
355 continue; /* dealt with exact match already. */
356 for (j = 0; j < rename_src_nr; j++) {
357 struct diff_filespec *one = rename_src[j].one;
358 struct diff_score *m = &mx[base+j];
359 m->src = j;
360 m->dst = i;
361 m->score = estimate_similarity(one, two,
362 minimum_score);
363 diff_free_filespec_data(one);
365 /* We do not need the text anymore */
366 diff_free_filespec_data(two);
367 dst_cnt++;
369 /* cost matrix sorted by most to least similar pair */
370 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
371 for (i = 0; i < num_create * num_src; i++) {
372 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
373 if (dst->pair)
374 continue; /* already done, either exact or fuzzy. */
375 if (mx[i].score < minimum_score)
376 break; /* there is no more usable pair. */
377 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
378 rename_count++;
380 free(mx);
382 cleanup:
383 /* At this point, we have found some renames and copies and they
384 * are recorded in rename_dst. The original list is still in *q.
386 outq.queue = NULL;
387 outq.nr = outq.alloc = 0;
388 for (i = 0; i < q->nr; i++) {
389 struct diff_filepair *p = q->queue[i];
390 struct diff_filepair *pair_to_free = NULL;
392 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
394 * Creation
396 * We would output this create record if it has
397 * not been turned into a rename/copy already.
399 struct diff_rename_dst *dst =
400 locate_rename_dst(p->two, 0);
401 if (dst && dst->pair) {
402 diff_q(&outq, dst->pair);
403 pair_to_free = p;
405 else
406 /* no matching rename/copy source, so
407 * record this as a creation.
409 diff_q(&outq, p);
411 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
413 * Deletion
415 * We would output this delete record if:
417 * (1) this is a broken delete and the counterpart
418 * broken create remains in the output; or
419 * (2) this is not a broken delete, and rename_dst
420 * does not have a rename/copy to move p->one->path
421 * out of existence.
423 * Otherwise, the counterpart broken create
424 * has been turned into a rename-edit; or
425 * delete did not have a matching create to
426 * begin with.
428 if (DIFF_PAIR_BROKEN(p)) {
429 /* broken delete */
430 struct diff_rename_dst *dst =
431 locate_rename_dst(p->one, 0);
432 if (dst && dst->pair)
433 /* counterpart is now rename/copy */
434 pair_to_free = p;
436 else {
437 for (j = 0; j < rename_dst_nr; j++) {
438 if (!rename_dst[j].pair)
439 continue;
440 if (strcmp(rename_dst[j].pair->
441 one->path,
442 p->one->path))
443 continue;
444 break;
446 if (j < rename_dst_nr)
447 /* this path remains */
448 pair_to_free = p;
451 if (pair_to_free)
453 else
454 diff_q(&outq, p);
456 else if (!diff_unmodified_pair(p))
457 /* all the usual ones need to be kept */
458 diff_q(&outq, p);
459 else
460 /* no need to keep unmodified pairs */
461 pair_to_free = p;
463 if (pair_to_free)
464 diff_free_filepair(pair_to_free);
466 diff_debug_queue("done copying original", &outq);
468 free(q->queue);
469 *q = outq;
470 diff_debug_queue("done collapsing", q);
472 /* We need to see which rename source really stays here;
473 * earlier we only checked if the path is left in the result,
474 * but even if a path remains in the result, if that is coming
475 * from copying something else on top of it, then the original
476 * source is lost and does not stay.
478 for (i = 0; i < q->nr; i++) {
479 struct diff_filepair *p = q->queue[i];
480 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
481 /* If one appears as the target of a rename-copy,
482 * then mark p->source_stays = 0; otherwise
483 * leave it as is.
485 p->source_stays = compute_stays(q, p->one);
489 for (i = 0; i < rename_dst_nr; i++) {
490 diff_free_filespec_data(rename_dst[i].two);
491 free(rename_dst[i].two);
494 free(rename_dst);
495 rename_dst = NULL;
496 rename_dst_nr = rename_dst_alloc = 0;
497 free(rename_src);
498 rename_src = NULL;
499 rename_src_nr = rename_src_alloc = 0;
500 return;