builtin-fsck: fix off by one head count
[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 */
156 if (!src->cnt_data && diff_populate_filespec(src, 0))
157 return 0;
158 if (!dst->cnt_data && diff_populate_filespec(dst, 0))
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
dc49cd76
SP
176 delta_limit = (unsigned long)
177 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
d8c3d03a 178 if (diffcore_count_changes(src, dst,
c06c7966 179 &src->cnt_data, &dst->cnt_data,
65416758
JH
180 delta_limit,
181 &src_copied, &literal_added))
85976974 182 return 0;
355e76a4 183
1706306a
JH
184 /* How similar are they?
185 * what percentage of material in dst are from source?
427dcb4b 186 */
90bd932c 187 if (!dst->size)
1706306a 188 score = 0; /* should not happen */
cfc0aef1 189 else
dc49cd76 190 score = (int)(src_copied * MAX_SCORE / max_size);
427dcb4b
JH
191 return score;
192}
193
5098bafb 194static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 195{
9fb88419 196 struct diff_filespec *src, *dst;
25d5ea41 197 struct diff_filepair *dp;
f7c1512a 198
25d5ea41
JH
199 if (rename_dst[dst_index].pair)
200 die("internal error: dst already matched.");
427dcb4b 201
25d5ea41 202 src = rename_src[src_index].one;
64479711 203 src->rename_used++;
9fb88419 204 src->count++;
427dcb4b 205
25d5ea41 206 dst = rename_dst[dst_index].two;
9fb88419 207 dst->count++;
427dcb4b 208
9fb88419 209 dp = diff_queue(NULL, src, dst);
ef677686 210 dp->renamed_pair = 1;
fc580719
JH
211 if (!strcmp(src->path, dst->path))
212 dp->score = rename_src[src_index].score;
213 else
214 dp->score = score;
25d5ea41 215 rename_dst[dst_index].pair = dp;
427dcb4b
JH
216}
217
218/*
219 * We sort the rename similarity matrix with the score, in descending
15d061b4 220 * order (the most similar first).
427dcb4b
JH
221 */
222static int score_compare(const void *a_, const void *b_)
223{
224 const struct diff_score *a = a_, *b = b_;
cfc0aef1 225
6d24ad97
JH
226 /* sink the unused ones to the bottom */
227 if (a->dst < 0)
228 return (0 <= b->dst);
229 else if (b->dst < 0)
230 return -1;
231
cfc0aef1
RS
232 if (a->score == b->score)
233 return b->name_score - a->name_score;
234
427dcb4b
JH
235 return b->score - a->score;
236}
237
9027f53c
LT
238struct file_similarity {
239 int src_dst, index;
240 struct diff_filespec *filespec;
241 struct file_similarity *next;
242};
243
244static int find_identical_files(struct file_similarity *src,
245 struct file_similarity *dst)
246{
247 int renames = 0;
248
249 /*
250 * Walk over all the destinations ...
251 */
252 do {
32d75d29 253 struct diff_filespec *target = dst->filespec;
9027f53c 254 struct file_similarity *p, *best;
32d75d29 255 int i = 100, best_score = -1;
9027f53c
LT
256
257 /*
258 * .. to find the best source match
259 */
260 best = NULL;
261 for (p = src; p; p = p->next) {
32d75d29
LT
262 int score;
263 struct diff_filespec *source = p->filespec;
9027f53c
LT
264
265 /* False hash collission? */
32d75d29 266 if (hashcmp(source->sha1, target->sha1))
9027f53c
LT
267 continue;
268 /* Non-regular files? If so, the modes must match! */
32d75d29
LT
269 if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) {
270 if (source->mode != target->mode)
9027f53c
LT
271 continue;
272 }
32d75d29
LT
273 /* Give higher scores to sources that haven't been used already */
274 score = !source->rename_used;
275 score += basename_same(source, target);
276 if (score > best_score) {
277 best = p;
278 best_score = score;
279 if (score == 2)
280 break;
281 }
9027f53c
LT
282
283 /* Too many identical alternatives? Pick one */
284 if (!--i)
285 break;
286 }
287 if (best) {
288 record_rename_pair(dst->index, best->index, MAX_SCORE);
289 renames++;
290 }
291 } while ((dst = dst->next) != NULL);
292 return renames;
293}
294
9027f53c
LT
295static void free_similarity_list(struct file_similarity *p)
296{
297 while (p) {
298 struct file_similarity *entry = p;
299 p = p->next;
9027f53c
LT
300 free(entry);
301 }
302}
303
304static int find_same_files(void *ptr)
305{
306 int ret;
307 struct file_similarity *p = ptr;
308 struct file_similarity *src = NULL, *dst = NULL;
309
310 /* Split the hash list up into sources and destinations */
311 do {
312 struct file_similarity *entry = p;
313 p = p->next;
314 if (entry->src_dst < 0) {
315 entry->next = src;
316 src = entry;
317 } else {
318 entry->next = dst;
319 dst = entry;
320 }
321 } while (p);
322
323 /*
324 * If we have both sources *and* destinations, see if
325 * we can match them up
326 */
327 ret = (src && dst) ? find_identical_files(src, dst) : 0;
328
329 /* Free the hashes and return the number of renames found */
330 free_similarity_list(src);
331 free_similarity_list(dst);
332 return ret;
333}
334
335static unsigned int hash_filespec(struct diff_filespec *filespec)
336{
337 unsigned int hash;
338 if (!filespec->sha1_valid) {
339 if (diff_populate_filespec(filespec, 0))
340 return 0;
341 hash_sha1_file(filespec->data, filespec->size, "blob", filespec->sha1);
342 }
343 memcpy(&hash, filespec->sha1, sizeof(hash));
344 return hash;
345}
346
347static void insert_file_table(struct hash_table *table, int src_dst, int index, struct diff_filespec *filespec)
348{
349 void **pos;
350 unsigned int hash;
351 struct file_similarity *entry = xmalloc(sizeof(*entry));
352
353 entry->src_dst = src_dst;
354 entry->index = index;
355 entry->filespec = filespec;
356 entry->next = NULL;
357
358 hash = hash_filespec(filespec);
359 pos = insert_hash(hash, entry, table);
360
361 /* We already had an entry there? */
362 if (pos) {
363 entry->next = *pos;
364 *pos = entry;
365 }
366}
367
cb1491b6
LT
368/*
369 * Find exact renames first.
370 *
371 * The first round matches up the up-to-date entries,
372 * and then during the second round we try to match
373 * cache-dirty entries as well.
cb1491b6
LT
374 */
375static int find_exact_renames(void)
376{
9027f53c
LT
377 int i;
378 struct hash_table file_table;
cb1491b6 379
9027f53c
LT
380 init_hash(&file_table);
381 for (i = 0; i < rename_src_nr; i++)
382 insert_file_table(&file_table, -1, i, rename_src[i].one);
383
384 for (i = 0; i < rename_dst_nr; i++)
385 insert_file_table(&file_table, 1, i, rename_dst[i].two);
386
387 /* Find the renames */
388 i = for_each_hash(&file_table, find_same_files);
389
390 /* .. and free the hash data structure */
391 free_hash(&file_table);
392
393 return i;
cb1491b6
LT
394}
395
6d24ad97
JH
396#define NUM_CANDIDATE_PER_DST 4
397static void record_if_better(struct diff_score m[], struct diff_score *o)
398{
399 int i, worst;
400
401 /* find the worst one */
402 worst = 0;
403 for (i = 1; i < NUM_CANDIDATE_PER_DST; i++)
404 if (score_compare(&m[i], &m[worst]) > 0)
405 worst = i;
406
407 /* is it better than the worst one? */
408 if (score_compare(&m[worst], o) > 0)
409 m[worst] = *o;
410}
411
8082d8d3 412void diffcore_rename(struct diff_options *options)
427dcb4b 413{
8082d8d3
JH
414 int detect_rename = options->detect_rename;
415 int minimum_score = options->rename_score;
416 int rename_limit = options->rename_limit;
38c6f780 417 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 418 struct diff_queue_struct outq;
427dcb4b 419 struct diff_score *mx;
cb1491b6 420 int i, j, rename_count;
25d5ea41 421 int num_create, num_src, dst_cnt;
427dcb4b 422
26dee0ad 423 if (!minimum_score)
f345b0a0 424 minimum_score = DEFAULT_RENAME_SCORE;
427dcb4b 425
427dcb4b 426 for (i = 0; i < q->nr; i++) {
52e95789 427 struct diff_filepair *p = q->queue[i];
2f3f8b21 428 if (!DIFF_FILE_VALID(p->one)) {
81e50eab 429 if (!DIFF_FILE_VALID(p->two))
60896c7b 430 continue; /* unmerged */
2f3f8b21
JH
431 else if (options->single_follow &&
432 strcmp(options->single_follow, p->two->path))
433 continue; /* not interested */
427dcb4b 434 else
25d5ea41 435 locate_rename_dst(p->two, 1);
2f3f8b21 436 }
2210100a 437 else if (!DIFF_FILE_VALID(p->two)) {
64479711
LT
438 /*
439 * If the source is a broken "delete", and
2210100a
JH
440 * they did not really want to get broken,
441 * that means the source actually stays.
64479711
LT
442 * So we increment the "rename_used" score
443 * by one, to indicate ourselves as a user
444 */
445 if (p->broken_pair && !p->score)
446 p->one->rename_used++;
447 register_rename_src(p->one, p->score);
448 }
449 else if (detect_rename == DIFF_DETECT_COPY) {
450 /*
451 * Increment the "rename_used" score by
452 * one, to indicate ourselves as a user.
2210100a 453 */
64479711
LT
454 p->one->rename_used++;
455 register_rename_src(p->one, p->score);
2210100a 456 }
427dcb4b 457 }
0024a549 458 if (rename_dst_nr == 0 || rename_src_nr == 0)
427dcb4b
JH
459 goto cleanup; /* nothing to do */
460
17559a64
LT
461 /*
462 * We really want to cull the candidates list early
463 * with cheap tests in order to avoid doing deltas.
464 */
465 rename_count = find_exact_renames();
466
42899ac8
LT
467 /* Did we only want exact renames? */
468 if (minimum_score == MAX_SCORE)
469 goto cleanup;
470
471 /*
472 * Calculate how many renames are left (but all the source
473 * files still remain as options for rename/copies!)
474 */
475 num_create = (rename_dst_nr - rename_count);
476 num_src = rename_src_nr;
477
478 /* All done? */
479 if (!num_create)
480 goto cleanup;
481
0024a549
LT
482 /*
483 * This basically does a test for the rename matrix not
484 * growing larger than a "rename_limit" square matrix, ie:
485 *
42899ac8 486 * num_create * num_src > rename_limit * rename_limit
0024a549
LT
487 *
488 * but handles the potential overflow case specially (and we
489 * assume at least 32-bit integers)
490 */
491 if (rename_limit <= 0 || rename_limit > 32767)
492 rename_limit = 32767;
ee542ee3
JK
493 if ((num_create > rename_limit && num_src > rename_limit) ||
494 (num_create * num_src > rename_limit * rename_limit)) {
b8960bbe 495 if (options->warn_on_too_large_rename)
6e381d3a 496 warning("too many files (created: %d deleted: %d), skipping inexact rename detection", num_create, num_src);
0024a549 497 goto cleanup;
ee542ee3 498 }
0024a549 499
6d24ad97 500 mx = xcalloc(num_create * NUM_CANDIDATE_PER_DST, sizeof(*mx));
25d5ea41 501 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
25d5ea41 502 struct diff_filespec *two = rename_dst[i].two;
6d24ad97
JH
503 struct diff_score *m;
504
25d5ea41 505 if (rename_dst[i].pair)
427dcb4b 506 continue; /* dealt with exact match already. */
6d24ad97
JH
507
508 m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST];
509 for (j = 0; j < NUM_CANDIDATE_PER_DST; j++)
510 m[j].dst = -1;
511
25d5ea41
JH
512 for (j = 0; j < rename_src_nr; j++) {
513 struct diff_filespec *one = rename_src[j].one;
6d24ad97
JH
514 struct diff_score this_src;
515 this_src.score = estimate_similarity(one, two,
516 minimum_score);
517 this_src.name_score = basename_same(one, two);
518 this_src.dst = i;
519 this_src.src = j;
520 record_if_better(m, &this_src);
8ae92e63 521 diff_free_filespec_blob(one);
427dcb4b 522 }
2821104d 523 /* We do not need the text anymore */
8ae92e63 524 diff_free_filespec_blob(two);
427dcb4b
JH
525 dst_cnt++;
526 }
6d24ad97 527
427dcb4b 528 /* cost matrix sorted by most to least similar pair */
6d24ad97
JH
529 qsort(mx, dst_cnt * NUM_CANDIDATE_PER_DST, sizeof(*mx), score_compare);
530
531 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
532 struct diff_rename_dst *dst;
533
534 if ((mx[i].dst < 0) ||
535 (mx[i].score < minimum_score))
536 break; /* there is no more usable pair. */
537 dst = &rename_dst[mx[i].dst];
9ae8fcb3
LT
538 if (dst->pair)
539 continue; /* already done, either exact or fuzzy. */
6d24ad97 540 if (rename_src[mx[i].src].one->rename_used)
9ae8fcb3
LT
541 continue;
542 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
543 rename_count++;
544 }
6d24ad97
JH
545
546 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
547 struct diff_rename_dst *dst;
548
549 if ((mx[i].dst < 0) ||
550 (mx[i].score < minimum_score))
551 break; /* there is no more usable pair. */
552 dst = &rename_dst[mx[i].dst];
25d5ea41
JH
553 if (dst->pair)
554 continue; /* already done, either exact or fuzzy. */
5098bafb
JH
555 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
556 rename_count++;
427dcb4b
JH
557 }
558 free(mx);
427dcb4b 559
15d061b4 560 cleanup:
427dcb4b 561 /* At this point, we have found some renames and copies and they
5098bafb 562 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 563 */
25d5ea41
JH
564 outq.queue = NULL;
565 outq.nr = outq.alloc = 0;
427dcb4b 566 for (i = 0; i < q->nr; i++) {
25d5ea41 567 struct diff_filepair *p = q->queue[i];
25d5ea41
JH
568 struct diff_filepair *pair_to_free = NULL;
569
2cd68882
JH
570 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
571 /*
572 * Creation
573 *
574 * We would output this create record if it has
575 * not been turned into a rename/copy already.
576 */
577 struct diff_rename_dst *dst =
578 locate_rename_dst(p->two, 0);
579 if (dst && dst->pair) {
25d5ea41
JH
580 diff_q(&outq, dst->pair);
581 pair_to_free = p;
582 }
583 else
2cd68882
JH
584 /* no matching rename/copy source, so
585 * record this as a creation.
25d5ea41
JH
586 */
587 diff_q(&outq, p);
427dcb4b 588 }
2cd68882
JH
589 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
590 /*
591 * Deletion
592 *
f345b0a0
JH
593 * We would output this delete record if:
594 *
595 * (1) this is a broken delete and the counterpart
596 * broken create remains in the output; or
5098bafb
JH
597 * (2) this is not a broken delete, and rename_dst
598 * does not have a rename/copy to move p->one->path
599 * out of existence.
f345b0a0
JH
600 *
601 * Otherwise, the counterpart broken create
602 * has been turned into a rename-edit; or
603 * delete did not have a matching create to
604 * begin with.
2cd68882 605 */
f345b0a0
JH
606 if (DIFF_PAIR_BROKEN(p)) {
607 /* broken delete */
608 struct diff_rename_dst *dst =
609 locate_rename_dst(p->one, 0);
610 if (dst && dst->pair)
611 /* counterpart is now rename/copy */
612 pair_to_free = p;
613 }
614 else {
64479711 615 if (p->one->rename_used)
f345b0a0
JH
616 /* this path remains */
617 pair_to_free = p;
618 }
2cd68882
JH
619
620 if (pair_to_free)
621 ;
622 else
623 diff_q(&outq, p);
624 }
25d5ea41 625 else if (!diff_unmodified_pair(p))
15d061b4 626 /* all the usual ones need to be kept */
25d5ea41 627 diff_q(&outq, p);
15d061b4
JH
628 else
629 /* no need to keep unmodified pairs */
630 pair_to_free = p;
631
226406f6
JH
632 if (pair_to_free)
633 diff_free_filepair(pair_to_free);
427dcb4b 634 }
25d5ea41 635 diff_debug_queue("done copying original", &outq);
427dcb4b 636
25d5ea41
JH
637 free(q->queue);
638 *q = outq;
639 diff_debug_queue("done collapsing", q);
427dcb4b 640
9fb88419
LT
641 for (i = 0; i < rename_dst_nr; i++)
642 free_filespec(rename_dst[i].two);
5098bafb 643
25d5ea41
JH
644 free(rename_dst);
645 rename_dst = NULL;
646 rename_dst_nr = rename_dst_alloc = 0;
647 free(rename_src);
648 rename_src = NULL;
649 rename_src_nr = rename_src_alloc = 0;
427dcb4b
JH
650 return;
651}