Git 1.7.4
[git/git.git] / diffcore-rename.c
CommitLineData
427dcb4b
JH
1/*
2 * Copyright (C) 2005 Junio C Hamano
3 */
4#include "cache.h"
5#include "diff.h"
6#include "diffcore.h"
9027f53c 7#include "hash.h"
427dcb4b 8
25d5ea41
JH
9/* Table of rename/copy destinations */
10
11static struct diff_rename_dst {
12 struct diff_filespec *two;
13 struct diff_filepair *pair;
14} *rename_dst;
15static int rename_dst_nr, rename_dst_alloc;
427dcb4b 16
25d5ea41
JH
17static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
18 int insert_ok)
427dcb4b 19{
25d5ea41
JH
20 int first, last;
21
22 first = 0;
23 last = rename_dst_nr;
24 while (last > first) {
25 int next = (last + first) >> 1;
26 struct diff_rename_dst *dst = &(rename_dst[next]);
27 int cmp = strcmp(two->path, dst->two->path);
28 if (!cmp)
29 return dst;
30 if (cmp < 0) {
31 last = next;
32 continue;
33 }
34 first = next+1;
35 }
36 /* not found */
37 if (!insert_ok)
38 return NULL;
39 /* insert to make it at "first" */
40 if (rename_dst_alloc <= rename_dst_nr) {
41 rename_dst_alloc = alloc_nr(rename_dst_alloc);
42 rename_dst = xrealloc(rename_dst,
43 rename_dst_alloc * sizeof(*rename_dst));
44 }
45 rename_dst_nr++;
46 if (first < rename_dst_nr)
47 memmove(rename_dst + first + 1, rename_dst + first,
48 (rename_dst_nr - first - 1) * sizeof(*rename_dst));
5098bafb
JH
49 rename_dst[first].two = alloc_filespec(two->path);
50 fill_filespec(rename_dst[first].two, two->sha1, two->mode);
25d5ea41
JH
51 rename_dst[first].pair = NULL;
52 return &(rename_dst[first]);
427dcb4b
JH
53}
54
15d061b4 55/* Table of rename/copy src files */
25d5ea41
JH
56static struct diff_rename_src {
57 struct diff_filespec *one;
fc580719 58 unsigned short score; /* to remember the break score */
25d5ea41
JH
59} *rename_src;
60static int rename_src_nr, rename_src_alloc;
427dcb4b 61
15d061b4 62static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
fc580719 63 unsigned short score)
25d5ea41
JH
64{
65 int first, last;
66
67 first = 0;
68 last = rename_src_nr;
69 while (last > first) {
70 int next = (last + first) >> 1;
71 struct diff_rename_src *src = &(rename_src[next]);
72 int cmp = strcmp(one->path, src->one->path);
73 if (!cmp)
74 return src;
75 if (cmp < 0) {
76 last = next;
77 continue;
78 }
79 first = next+1;
80 }
15d061b4 81
25d5ea41
JH
82 /* insert to make it at "first" */
83 if (rename_src_alloc <= rename_src_nr) {
84 rename_src_alloc = alloc_nr(rename_src_alloc);
85 rename_src = xrealloc(rename_src,
86 rename_src_alloc * sizeof(*rename_src));
427dcb4b 87 }
25d5ea41
JH
88 rename_src_nr++;
89 if (first < rename_src_nr)
90 memmove(rename_src + first + 1, rename_src + first,
91 (rename_src_nr - first - 1) * sizeof(*rename_src));
92 rename_src[first].one = one;
fc580719 93 rename_src[first].score = score;
25d5ea41 94 return &(rename_src[first]);
427dcb4b
JH
95}
96
0ce39643
JS
97static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
98{
99 int src_len = strlen(src->path), dst_len = strlen(dst->path);
100 while (src_len && dst_len) {
101 char c1 = src->path[--src_len];
102 char c2 = dst->path[--dst_len];
103 if (c1 != c2)
104 return 0;
105 if (c1 == '/')
106 return 1;
107 }
108 return (!src_len || src->path[src_len - 1] == '/') &&
109 (!dst_len || dst->path[dst_len - 1] == '/');
110}
111
427dcb4b 112struct diff_score {
25d5ea41
JH
113 int src; /* index in rename_src */
114 int dst; /* index in rename_dst */
6d24ad97
JH
115 unsigned short score;
116 short name_score;
427dcb4b
JH
117};
118
119static int estimate_similarity(struct diff_filespec *src,
120 struct diff_filespec *dst,
121 int minimum_score)
122{
123 /* src points at a file that existed in the original tree (or
124 * optionally a file in the destination tree) and dst points
125 * at a newly created file. They may be quite similar, in which
126 * case we want to say src is renamed to dst or src is copied into
127 * dst, and then some edit has been applied to dst.
128 *
129 * Compare them and return how similar they are, representing
f0c6b2a2
JH
130 * the score as an integer between 0 and MAX_SCORE.
131 *
132 * When there is an exact match, it is considered a better
133 * match than anything else; the destination does not even
134 * call into this function in that case.
427dcb4b 135 */
90bd932c 136 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
75c660ac 137 unsigned long delta_limit;
427dcb4b
JH
138 int score;
139
60896c7b
JH
140 /* We deal only with regular files. Symlink renames are handled
141 * only when they are exact matches --- in other words, no edits
142 * after renaming.
143 */
144 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
145 return 0;
146
81ac051d
LT
147 /*
148 * Need to check that source and destination sizes are
149 * filled in before comparing them.
150 *
151 * If we already have "cnt_data" filled in, we know it's
152 * all good (avoid checking the size for zero, as that
153 * is a possible size - we really should have a flag to
154 * say whether the size is valid or not!)
155 */
885c716f 156 if (!src->cnt_data && diff_populate_filespec(src, 1))
81ac051d 157 return 0;
885c716f 158 if (!dst->cnt_data && diff_populate_filespec(dst, 1))
81ac051d
LT
159 return 0;
160
90bd932c 161 max_size = ((src->size > dst->size) ? src->size : dst->size);
58b103f5 162 base_size = ((src->size < dst->size) ? src->size : dst->size);
90bd932c 163 delta_size = max_size - base_size;
427dcb4b 164
58b103f5
JH
165 /* We would not consider edits that change the file size so
166 * drastically. delta_size must be smaller than
cd1870ed 167 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
f0c6b2a2 168 *
58b103f5
JH
169 * Note that base_size == 0 case is handled here already
170 * and the final score computation below would not have a
171 * divide-by-zero issue.
427dcb4b 172 */
cd1870ed 173 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
427dcb4b
JH
174 return 0;
175
885c716f
BS
176 if (!src->cnt_data && diff_populate_filespec(src, 0))
177 return 0;
178 if (!dst->cnt_data && diff_populate_filespec(dst, 0))
179 return 0;
180
dc49cd76
SP
181 delta_limit = (unsigned long)
182 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
d8c3d03a 183 if (diffcore_count_changes(src, dst,
c06c7966 184 &src->cnt_data, &dst->cnt_data,
65416758
JH
185 delta_limit,
186 &src_copied, &literal_added))
85976974 187 return 0;
355e76a4 188
1706306a
JH
189 /* How similar are they?
190 * what percentage of material in dst are from source?
427dcb4b 191 */
90bd932c 192 if (!dst->size)
1706306a 193 score = 0; /* should not happen */
cfc0aef1 194 else
dc49cd76 195 score = (int)(src_copied * MAX_SCORE / max_size);
427dcb4b
JH
196 return score;
197}
198
5098bafb 199static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 200{
9fb88419 201 struct diff_filespec *src, *dst;
25d5ea41 202 struct diff_filepair *dp;
f7c1512a 203
25d5ea41
JH
204 if (rename_dst[dst_index].pair)
205 die("internal error: dst already matched.");
427dcb4b 206
25d5ea41 207 src = rename_src[src_index].one;
64479711 208 src->rename_used++;
9fb88419 209 src->count++;
427dcb4b 210
25d5ea41 211 dst = rename_dst[dst_index].two;
9fb88419 212 dst->count++;
427dcb4b 213
9fb88419 214 dp = diff_queue(NULL, src, dst);
ef677686 215 dp->renamed_pair = 1;
fc580719
JH
216 if (!strcmp(src->path, dst->path))
217 dp->score = rename_src[src_index].score;
218 else
219 dp->score = score;
25d5ea41 220 rename_dst[dst_index].pair = dp;
427dcb4b
JH
221}
222
223/*
224 * We sort the rename similarity matrix with the score, in descending
15d061b4 225 * order (the most similar first).
427dcb4b
JH
226 */
227static int score_compare(const void *a_, const void *b_)
228{
229 const struct diff_score *a = a_, *b = b_;
cfc0aef1 230
6d24ad97
JH
231 /* sink the unused ones to the bottom */
232 if (a->dst < 0)
233 return (0 <= b->dst);
234 else if (b->dst < 0)
235 return -1;
236
cfc0aef1
RS
237 if (a->score == b->score)
238 return b->name_score - a->name_score;
239
427dcb4b
JH
240 return b->score - a->score;
241}
242
9027f53c
LT
243struct file_similarity {
244 int src_dst, index;
245 struct diff_filespec *filespec;
246 struct file_similarity *next;
247};
248
249static int find_identical_files(struct file_similarity *src,
250 struct file_similarity *dst)
251{
252 int renames = 0;
253
254 /*
255 * Walk over all the destinations ...
256 */
257 do {
32d75d29 258 struct diff_filespec *target = dst->filespec;
9027f53c 259 struct file_similarity *p, *best;
32d75d29 260 int i = 100, best_score = -1;
9027f53c
LT
261
262 /*
263 * .. to find the best source match
264 */
265 best = NULL;
266 for (p = src; p; p = p->next) {
32d75d29
LT
267 int score;
268 struct diff_filespec *source = p->filespec;
9027f53c 269
3ea3c215 270 /* False hash collision? */
32d75d29 271 if (hashcmp(source->sha1, target->sha1))
9027f53c
LT
272 continue;
273 /* Non-regular files? If so, the modes must match! */
32d75d29
LT
274 if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) {
275 if (source->mode != target->mode)
9027f53c
LT
276 continue;
277 }
32d75d29
LT
278 /* Give higher scores to sources that haven't been used already */
279 score = !source->rename_used;
280 score += basename_same(source, target);
281 if (score > best_score) {
282 best = p;
283 best_score = score;
284 if (score == 2)
285 break;
286 }
9027f53c
LT
287
288 /* Too many identical alternatives? Pick one */
289 if (!--i)
290 break;
291 }
292 if (best) {
293 record_rename_pair(dst->index, best->index, MAX_SCORE);
294 renames++;
295 }
296 } while ((dst = dst->next) != NULL);
297 return renames;
298}
299
9027f53c
LT
300static void free_similarity_list(struct file_similarity *p)
301{
302 while (p) {
303 struct file_similarity *entry = p;
304 p = p->next;
9027f53c
LT
305 free(entry);
306 }
307}
308
309static int find_same_files(void *ptr)
310{
311 int ret;
312 struct file_similarity *p = ptr;
313 struct file_similarity *src = NULL, *dst = NULL;
314
315 /* Split the hash list up into sources and destinations */
316 do {
317 struct file_similarity *entry = p;
318 p = p->next;
319 if (entry->src_dst < 0) {
320 entry->next = src;
321 src = entry;
322 } else {
323 entry->next = dst;
324 dst = entry;
325 }
326 } while (p);
327
328 /*
329 * If we have both sources *and* destinations, see if
330 * we can match them up
331 */
332 ret = (src && dst) ? find_identical_files(src, dst) : 0;
333
334 /* Free the hashes and return the number of renames found */
335 free_similarity_list(src);
336 free_similarity_list(dst);
337 return ret;
338}
339
340static unsigned int hash_filespec(struct diff_filespec *filespec)
341{
342 unsigned int hash;
343 if (!filespec->sha1_valid) {
344 if (diff_populate_filespec(filespec, 0))
345 return 0;
346 hash_sha1_file(filespec->data, filespec->size, "blob", filespec->sha1);
347 }
348 memcpy(&hash, filespec->sha1, sizeof(hash));
349 return hash;
350}
351
352static void insert_file_table(struct hash_table *table, int src_dst, int index, struct diff_filespec *filespec)
353{
354 void **pos;
355 unsigned int hash;
356 struct file_similarity *entry = xmalloc(sizeof(*entry));
357
358 entry->src_dst = src_dst;
359 entry->index = index;
360 entry->filespec = filespec;
361 entry->next = NULL;
362
363 hash = hash_filespec(filespec);
364 pos = insert_hash(hash, entry, table);
365
366 /* We already had an entry there? */
367 if (pos) {
368 entry->next = *pos;
369 *pos = entry;
370 }
371}
372
cb1491b6
LT
373/*
374 * Find exact renames first.
375 *
376 * The first round matches up the up-to-date entries,
377 * and then during the second round we try to match
378 * cache-dirty entries as well.
cb1491b6
LT
379 */
380static int find_exact_renames(void)
381{
9027f53c
LT
382 int i;
383 struct hash_table file_table;
cb1491b6 384
9027f53c
LT
385 init_hash(&file_table);
386 for (i = 0; i < rename_src_nr; i++)
387 insert_file_table(&file_table, -1, i, rename_src[i].one);
388
389 for (i = 0; i < rename_dst_nr; i++)
390 insert_file_table(&file_table, 1, i, rename_dst[i].two);
391
392 /* Find the renames */
393 i = for_each_hash(&file_table, find_same_files);
394
395 /* .. and free the hash data structure */
396 free_hash(&file_table);
397
398 return i;
cb1491b6
LT
399}
400
6d24ad97
JH
401#define NUM_CANDIDATE_PER_DST 4
402static void record_if_better(struct diff_score m[], struct diff_score *o)
403{
404 int i, worst;
405
406 /* find the worst one */
407 worst = 0;
408 for (i = 1; i < NUM_CANDIDATE_PER_DST; i++)
409 if (score_compare(&m[i], &m[worst]) > 0)
410 worst = i;
411
412 /* is it better than the worst one? */
413 if (score_compare(&m[worst], o) > 0)
414 m[worst] = *o;
415}
416
8082d8d3 417void diffcore_rename(struct diff_options *options)
427dcb4b 418{
8082d8d3
JH
419 int detect_rename = options->detect_rename;
420 int minimum_score = options->rename_score;
421 int rename_limit = options->rename_limit;
38c6f780 422 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 423 struct diff_queue_struct outq;
427dcb4b 424 struct diff_score *mx;
cb1491b6 425 int i, j, rename_count;
25d5ea41 426 int num_create, num_src, dst_cnt;
427dcb4b 427
26dee0ad 428 if (!minimum_score)
f345b0a0 429 minimum_score = DEFAULT_RENAME_SCORE;
427dcb4b 430
427dcb4b 431 for (i = 0; i < q->nr; i++) {
52e95789 432 struct diff_filepair *p = q->queue[i];
2f3f8b21 433 if (!DIFF_FILE_VALID(p->one)) {
81e50eab 434 if (!DIFF_FILE_VALID(p->two))
60896c7b 435 continue; /* unmerged */
2f3f8b21
JH
436 else if (options->single_follow &&
437 strcmp(options->single_follow, p->two->path))
438 continue; /* not interested */
427dcb4b 439 else
25d5ea41 440 locate_rename_dst(p->two, 1);
2f3f8b21 441 }
2210100a 442 else if (!DIFF_FILE_VALID(p->two)) {
64479711
LT
443 /*
444 * If the source is a broken "delete", and
2210100a
JH
445 * they did not really want to get broken,
446 * that means the source actually stays.
64479711
LT
447 * So we increment the "rename_used" score
448 * by one, to indicate ourselves as a user
449 */
450 if (p->broken_pair && !p->score)
451 p->one->rename_used++;
452 register_rename_src(p->one, p->score);
453 }
454 else if (detect_rename == DIFF_DETECT_COPY) {
455 /*
456 * Increment the "rename_used" score by
457 * one, to indicate ourselves as a user.
2210100a 458 */
64479711
LT
459 p->one->rename_used++;
460 register_rename_src(p->one, p->score);
2210100a 461 }
427dcb4b 462 }
0024a549 463 if (rename_dst_nr == 0 || rename_src_nr == 0)
427dcb4b
JH
464 goto cleanup; /* nothing to do */
465
17559a64
LT
466 /*
467 * We really want to cull the candidates list early
468 * with cheap tests in order to avoid doing deltas.
469 */
470 rename_count = find_exact_renames();
471
42899ac8
LT
472 /* Did we only want exact renames? */
473 if (minimum_score == MAX_SCORE)
474 goto cleanup;
475
476 /*
477 * Calculate how many renames are left (but all the source
478 * files still remain as options for rename/copies!)
479 */
480 num_create = (rename_dst_nr - rename_count);
481 num_src = rename_src_nr;
482
483 /* All done? */
484 if (!num_create)
485 goto cleanup;
486
0024a549
LT
487 /*
488 * This basically does a test for the rename matrix not
489 * growing larger than a "rename_limit" square matrix, ie:
490 *
42899ac8 491 * num_create * num_src > rename_limit * rename_limit
0024a549
LT
492 *
493 * but handles the potential overflow case specially (and we
494 * assume at least 32-bit integers)
495 */
496 if (rename_limit <= 0 || rename_limit > 32767)
497 rename_limit = 32767;
ee542ee3
JK
498 if ((num_create > rename_limit && num_src > rename_limit) ||
499 (num_create * num_src > rename_limit * rename_limit)) {
b8960bbe 500 if (options->warn_on_too_large_rename)
6e381d3a 501 warning("too many files (created: %d deleted: %d), skipping inexact rename detection", num_create, num_src);
0024a549 502 goto cleanup;
ee542ee3 503 }
0024a549 504
6d24ad97 505 mx = xcalloc(num_create * NUM_CANDIDATE_PER_DST, sizeof(*mx));
25d5ea41 506 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
25d5ea41 507 struct diff_filespec *two = rename_dst[i].two;
6d24ad97
JH
508 struct diff_score *m;
509
25d5ea41 510 if (rename_dst[i].pair)
427dcb4b 511 continue; /* dealt with exact match already. */
6d24ad97
JH
512
513 m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST];
514 for (j = 0; j < NUM_CANDIDATE_PER_DST; j++)
515 m[j].dst = -1;
516
25d5ea41
JH
517 for (j = 0; j < rename_src_nr; j++) {
518 struct diff_filespec *one = rename_src[j].one;
6d24ad97
JH
519 struct diff_score this_src;
520 this_src.score = estimate_similarity(one, two,
521 minimum_score);
522 this_src.name_score = basename_same(one, two);
523 this_src.dst = i;
524 this_src.src = j;
525 record_if_better(m, &this_src);
809809bb
JH
526 /*
527 * Once we run estimate_similarity,
528 * We do not need the text anymore.
529 */
8ae92e63 530 diff_free_filespec_blob(one);
809809bb 531 diff_free_filespec_blob(two);
427dcb4b
JH
532 }
533 dst_cnt++;
534 }
6d24ad97 535
427dcb4b 536 /* cost matrix sorted by most to least similar pair */
6d24ad97
JH
537 qsort(mx, dst_cnt * NUM_CANDIDATE_PER_DST, sizeof(*mx), score_compare);
538
539 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
540 struct diff_rename_dst *dst;
541
542 if ((mx[i].dst < 0) ||
543 (mx[i].score < minimum_score))
544 break; /* there is no more usable pair. */
545 dst = &rename_dst[mx[i].dst];
9ae8fcb3
LT
546 if (dst->pair)
547 continue; /* already done, either exact or fuzzy. */
6d24ad97 548 if (rename_src[mx[i].src].one->rename_used)
9ae8fcb3
LT
549 continue;
550 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
551 rename_count++;
552 }
6d24ad97
JH
553
554 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
555 struct diff_rename_dst *dst;
556
557 if ((mx[i].dst < 0) ||
558 (mx[i].score < minimum_score))
559 break; /* there is no more usable pair. */
560 dst = &rename_dst[mx[i].dst];
25d5ea41
JH
561 if (dst->pair)
562 continue; /* already done, either exact or fuzzy. */
5098bafb
JH
563 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
564 rename_count++;
427dcb4b
JH
565 }
566 free(mx);
427dcb4b 567
15d061b4 568 cleanup:
427dcb4b 569 /* At this point, we have found some renames and copies and they
5098bafb 570 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 571 */
9ca5df90 572 DIFF_QUEUE_CLEAR(&outq);
427dcb4b 573 for (i = 0; i < q->nr; i++) {
25d5ea41 574 struct diff_filepair *p = q->queue[i];
25d5ea41
JH
575 struct diff_filepair *pair_to_free = NULL;
576
2cd68882
JH
577 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
578 /*
579 * Creation
580 *
581 * We would output this create record if it has
582 * not been turned into a rename/copy already.
583 */
584 struct diff_rename_dst *dst =
585 locate_rename_dst(p->two, 0);
586 if (dst && dst->pair) {
25d5ea41
JH
587 diff_q(&outq, dst->pair);
588 pair_to_free = p;
589 }
590 else
2cd68882
JH
591 /* no matching rename/copy source, so
592 * record this as a creation.
25d5ea41
JH
593 */
594 diff_q(&outq, p);
427dcb4b 595 }
2cd68882
JH
596 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
597 /*
598 * Deletion
599 *
f345b0a0
JH
600 * We would output this delete record if:
601 *
602 * (1) this is a broken delete and the counterpart
603 * broken create remains in the output; or
5098bafb
JH
604 * (2) this is not a broken delete, and rename_dst
605 * does not have a rename/copy to move p->one->path
606 * out of existence.
f345b0a0
JH
607 *
608 * Otherwise, the counterpart broken create
609 * has been turned into a rename-edit; or
610 * delete did not have a matching create to
611 * begin with.
2cd68882 612 */
f345b0a0
JH
613 if (DIFF_PAIR_BROKEN(p)) {
614 /* broken delete */
615 struct diff_rename_dst *dst =
616 locate_rename_dst(p->one, 0);
617 if (dst && dst->pair)
618 /* counterpart is now rename/copy */
619 pair_to_free = p;
620 }
621 else {
64479711 622 if (p->one->rename_used)
f345b0a0
JH
623 /* this path remains */
624 pair_to_free = p;
625 }
2cd68882
JH
626
627 if (pair_to_free)
628 ;
629 else
630 diff_q(&outq, p);
631 }
25d5ea41 632 else if (!diff_unmodified_pair(p))
15d061b4 633 /* all the usual ones need to be kept */
25d5ea41 634 diff_q(&outq, p);
15d061b4
JH
635 else
636 /* no need to keep unmodified pairs */
637 pair_to_free = p;
638
226406f6
JH
639 if (pair_to_free)
640 diff_free_filepair(pair_to_free);
427dcb4b 641 }
25d5ea41 642 diff_debug_queue("done copying original", &outq);
427dcb4b 643
25d5ea41
JH
644 free(q->queue);
645 *q = outq;
646 diff_debug_queue("done collapsing", q);
427dcb4b 647
9fb88419
LT
648 for (i = 0; i < rename_dst_nr; i++)
649 free_filespec(rename_dst[i].two);
5098bafb 650
25d5ea41
JH
651 free(rename_dst);
652 rename_dst = NULL;
653 rename_dst_nr = rename_dst_alloc = 0;
654 free(rename_src);
655 rename_src = NULL;
656 rename_src_nr = rename_src_alloc = 0;
427dcb4b
JH
657 return;
658}