Add 'diffcore.h' to LIB_H
[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"
427dcb4b 7
25d5ea41
JH
8/* Table of rename/copy destinations */
9
10static struct diff_rename_dst {
11 struct diff_filespec *two;
12 struct diff_filepair *pair;
13} *rename_dst;
14static int rename_dst_nr, rename_dst_alloc;
427dcb4b 15
25d5ea41
JH
16static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
17 int insert_ok)
427dcb4b 18{
25d5ea41
JH
19 int first, last;
20
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;
32 }
33 first = next+1;
34 }
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));
43 }
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));
5098bafb
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48 rename_dst[first].two = alloc_filespec(two->path);
49 fill_filespec(rename_dst[first].two, two->sha1, two->mode);
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50 rename_dst[first].pair = NULL;
51 return &(rename_dst[first]);
427dcb4b
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52}
53
15d061b4 54/* Table of rename/copy src files */
25d5ea41
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55static struct diff_rename_src {
56 struct diff_filespec *one;
fc580719 57 unsigned short score; /* to remember the break score */
6bac10d8 58 unsigned src_path_left : 1;
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
JH
63 int src_path_left,
64 unsigned short score)
25d5ea41
JH
65{
66 int first, last;
67
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;
79 }
80 first = next+1;
81 }
15d061b4 82
25d5ea41
JH
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));
427dcb4b 88 }
25d5ea41
JH
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;
fc580719 94 rename_src[first].score = score;
6bac10d8 95 rename_src[first].src_path_left = src_path_left;
25d5ea41 96 return &(rename_src[first]);
427dcb4b
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97}
98
17e6019a
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99static int is_exact_match(struct diff_filespec *src,
100 struct diff_filespec *dst,
101 int contents_too)
427dcb4b
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102{
103 if (src->sha1_valid && dst->sha1_valid &&
a89fccd2 104 !hashcmp(src->sha1, dst->sha1))
427dcb4b 105 return 1;
17e6019a
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106 if (!contents_too)
107 return 0;
f0c6b2a2
JH
108 if (diff_populate_filespec(src, 1) || diff_populate_filespec(dst, 1))
109 return 0;
110 if (src->size != dst->size)
111 return 0;
7da41f48
SP
112 if (src->sha1_valid && dst->sha1_valid)
113 return !hashcmp(src->sha1, dst->sha1);
f0c6b2a2 114 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
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115 return 0;
116 if (src->size == dst->size &&
117 !memcmp(src->data, dst->data, src->size))
118 return 1;
119 return 0;
120}
121
0ce39643
JS
122static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
123{
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;
132 }
133 return (!src_len || src->path[src_len - 1] == '/') &&
134 (!dst_len || dst->path[dst_len - 1] == '/');
135}
136
427dcb4b 137struct diff_score {
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138 int src; /* index in rename_src */
139 int dst; /* index in rename_dst */
427dcb4b 140 int score;
cfc0aef1 141 int name_score;
427dcb4b
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142};
143
144static int estimate_similarity(struct diff_filespec *src,
145 struct diff_filespec *dst,
146 int minimum_score)
147{
148 /* src points at a file that existed in the original tree (or
149 * optionally a file in the destination tree) and dst points
150 * at a newly created file. They may be quite similar, in which
151 * case we want to say src is renamed to dst or src is copied into
152 * dst, and then some edit has been applied to dst.
153 *
154 * Compare them and return how similar they are, representing
f0c6b2a2
JH
155 * the score as an integer between 0 and MAX_SCORE.
156 *
157 * When there is an exact match, it is considered a better
158 * match than anything else; the destination does not even
159 * call into this function in that case.
427dcb4b 160 */
90bd932c 161 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
75c660ac 162 unsigned long delta_limit;
427dcb4b
JH
163 int score;
164
60896c7b
JH
165 /* We deal only with regular files. Symlink renames are handled
166 * only when they are exact matches --- in other words, no edits
167 * after renaming.
168 */
169 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
170 return 0;
171
90bd932c 172 max_size = ((src->size > dst->size) ? src->size : dst->size);
58b103f5 173 base_size = ((src->size < dst->size) ? src->size : dst->size);
90bd932c 174 delta_size = max_size - base_size;
427dcb4b 175
58b103f5
JH
176 /* We would not consider edits that change the file size so
177 * drastically. delta_size must be smaller than
cd1870ed 178 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
f0c6b2a2 179 *
58b103f5
JH
180 * Note that base_size == 0 case is handled here already
181 * and the final score computation below would not have a
182 * divide-by-zero issue.
427dcb4b 183 */
cd1870ed 184 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
427dcb4b
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185 return 0;
186
eede7b7d
JK
187 if ((!src->cnt_data && diff_populate_filespec(src, 0))
188 || (!dst->cnt_data && diff_populate_filespec(dst, 0)))
f0c6b2a2
JH
189 return 0; /* error but caught downstream */
190
85976974 191
dc49cd76
SP
192 delta_limit = (unsigned long)
193 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
d8c3d03a 194 if (diffcore_count_changes(src, dst,
c06c7966 195 &src->cnt_data, &dst->cnt_data,
65416758
JH
196 delta_limit,
197 &src_copied, &literal_added))
85976974 198 return 0;
355e76a4 199
1706306a
JH
200 /* How similar are they?
201 * what percentage of material in dst are from source?
427dcb4b 202 */
90bd932c 203 if (!dst->size)
1706306a 204 score = 0; /* should not happen */
cfc0aef1 205 else
dc49cd76 206 score = (int)(src_copied * MAX_SCORE / max_size);
427dcb4b
JH
207 return score;
208}
209
5098bafb 210static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 211{
25d5ea41
JH
212 struct diff_filespec *one, *two, *src, *dst;
213 struct diff_filepair *dp;
f7c1512a 214
25d5ea41
JH
215 if (rename_dst[dst_index].pair)
216 die("internal error: dst already matched.");
427dcb4b 217
25d5ea41
JH
218 src = rename_src[src_index].one;
219 one = alloc_filespec(src->path);
220 fill_filespec(one, src->sha1, src->mode);
427dcb4b 221
25d5ea41
JH
222 dst = rename_dst[dst_index].two;
223 two = alloc_filespec(dst->path);
224 fill_filespec(two, dst->sha1, dst->mode);
427dcb4b 225
5098bafb 226 dp = diff_queue(NULL, one, two);
ef677686 227 dp->renamed_pair = 1;
fc580719
JH
228 if (!strcmp(src->path, dst->path))
229 dp->score = rename_src[src_index].score;
230 else
231 dp->score = score;
6bac10d8 232 dp->source_stays = rename_src[src_index].src_path_left;
25d5ea41 233 rename_dst[dst_index].pair = dp;
427dcb4b
JH
234}
235
236/*
237 * We sort the rename similarity matrix with the score, in descending
15d061b4 238 * order (the most similar first).
427dcb4b
JH
239 */
240static int score_compare(const void *a_, const void *b_)
241{
242 const struct diff_score *a = a_, *b = b_;
cfc0aef1
RS
243
244 if (a->score == b->score)
245 return b->name_score - a->name_score;
246
427dcb4b
JH
247 return b->score - a->score;
248}
249
6bac10d8
JH
250static int compute_stays(struct diff_queue_struct *q,
251 struct diff_filespec *one)
252{
253 int i;
254 for (i = 0; i < q->nr; i++) {
255 struct diff_filepair *p = q->queue[i];
256 if (strcmp(one->path, p->two->path))
257 continue;
258 if (DIFF_PAIR_RENAME(p)) {
259 return 0; /* something else is renamed into this */
260 }
261 }
262 return 1;
263}
264
8082d8d3 265void diffcore_rename(struct diff_options *options)
427dcb4b 266{
8082d8d3
JH
267 int detect_rename = options->detect_rename;
268 int minimum_score = options->rename_score;
269 int rename_limit = options->rename_limit;
38c6f780 270 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 271 struct diff_queue_struct outq;
427dcb4b 272 struct diff_score *mx;
17e6019a 273 int i, j, rename_count, contents_too;
25d5ea41 274 int num_create, num_src, dst_cnt;
427dcb4b 275
26dee0ad 276 if (!minimum_score)
f345b0a0 277 minimum_score = DEFAULT_RENAME_SCORE;
5098bafb 278 rename_count = 0;
427dcb4b 279
427dcb4b 280 for (i = 0; i < q->nr; i++) {
52e95789 281 struct diff_filepair *p = q->queue[i];
2f3f8b21 282 if (!DIFF_FILE_VALID(p->one)) {
81e50eab 283 if (!DIFF_FILE_VALID(p->two))
60896c7b 284 continue; /* unmerged */
2f3f8b21
JH
285 else if (options->single_follow &&
286 strcmp(options->single_follow, p->two->path))
287 continue; /* not interested */
427dcb4b 288 else
25d5ea41 289 locate_rename_dst(p->two, 1);
2f3f8b21 290 }
2210100a
JH
291 else if (!DIFF_FILE_VALID(p->two)) {
292 /* If the source is a broken "delete", and
293 * they did not really want to get broken,
294 * that means the source actually stays.
295 */
296 int stays = (p->broken_pair && !p->score);
fc580719 297 register_rename_src(p->one, stays, p->score);
2210100a 298 }
15d061b4 299 else if (detect_rename == DIFF_DETECT_COPY)
fc580719 300 register_rename_src(p->one, 1, p->score);
427dcb4b 301 }
0024a549 302 if (rename_dst_nr == 0 || rename_src_nr == 0)
427dcb4b
JH
303 goto cleanup; /* nothing to do */
304
0024a549
LT
305 /*
306 * This basically does a test for the rename matrix not
307 * growing larger than a "rename_limit" square matrix, ie:
308 *
309 * rename_dst_nr * rename_src_nr > rename_limit * rename_limit
310 *
311 * but handles the potential overflow case specially (and we
312 * assume at least 32-bit integers)
313 */
314 if (rename_limit <= 0 || rename_limit > 32767)
315 rename_limit = 32767;
316 if (rename_dst_nr > rename_limit && rename_src_nr > rename_limit)
317 goto cleanup;
318 if (rename_dst_nr * rename_src_nr > rename_limit * rename_limit)
319 goto cleanup;
320
427dcb4b
JH
321 /* We really want to cull the candidates list early
322 * with cheap tests in order to avoid doing deltas.
17e6019a
JH
323 * The first round matches up the up-to-date entries,
324 * and then during the second round we try to match
325 * cache-dirty entries as well.
427dcb4b 326 */
17e6019a
JH
327 for (contents_too = 0; contents_too < 2; contents_too++) {
328 for (i = 0; i < rename_dst_nr; i++) {
329 struct diff_filespec *two = rename_dst[i].two;
330 if (rename_dst[i].pair)
331 continue; /* dealt with an earlier round */
332 for (j = 0; j < rename_src_nr; j++) {
0ce39643 333 int k;
17e6019a
JH
334 struct diff_filespec *one = rename_src[j].one;
335 if (!is_exact_match(one, two, contents_too))
336 continue;
0ce39643
JS
337
338 /* see if there is a basename match, too */
339 for (k = j; k < rename_src_nr; k++) {
340 one = rename_src[k].one;
341 if (basename_same(one, two) &&
342 is_exact_match(one, two,
343 contents_too)) {
344 j = k;
345 break;
346 }
347 }
348
dc49cd76 349 record_rename_pair(i, j, (int)MAX_SCORE);
17e6019a
JH
350 rename_count++;
351 break; /* we are done with this entry */
352 }
427dcb4b
JH
353 }
354 }
427dcb4b
JH
355
356 /* Have we run out the created file pool? If so we can avoid
357 * doing the delta matrix altogether.
358 */
5098bafb 359 if (rename_count == rename_dst_nr)
15d061b4 360 goto cleanup;
427dcb4b 361
9f70b806
JH
362 if (minimum_score == MAX_SCORE)
363 goto cleanup;
364
5098bafb 365 num_create = (rename_dst_nr - rename_count);
25d5ea41 366 num_src = rename_src_nr;
427dcb4b 367 mx = xmalloc(sizeof(*mx) * num_create * num_src);
25d5ea41 368 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
427dcb4b 369 int base = dst_cnt * num_src;
25d5ea41
JH
370 struct diff_filespec *two = rename_dst[i].two;
371 if (rename_dst[i].pair)
427dcb4b 372 continue; /* dealt with exact match already. */
25d5ea41
JH
373 for (j = 0; j < rename_src_nr; j++) {
374 struct diff_filespec *one = rename_src[j].one;
375 struct diff_score *m = &mx[base+j];
376 m->src = j;
377 m->dst = i;
378 m->score = estimate_similarity(one, two,
379 minimum_score);
cfc0aef1 380 m->name_score = basename_same(one, two);
8ae92e63 381 diff_free_filespec_blob(one);
427dcb4b 382 }
2821104d 383 /* We do not need the text anymore */
8ae92e63 384 diff_free_filespec_blob(two);
427dcb4b
JH
385 dst_cnt++;
386 }
387 /* cost matrix sorted by most to least similar pair */
388 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
389 for (i = 0; i < num_create * num_src; i++) {
25d5ea41
JH
390 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
391 if (dst->pair)
392 continue; /* already done, either exact or fuzzy. */
427dcb4b 393 if (mx[i].score < minimum_score)
15d061b4 394 break; /* there is no more usable pair. */
5098bafb
JH
395 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
396 rename_count++;
427dcb4b
JH
397 }
398 free(mx);
427dcb4b 399
15d061b4 400 cleanup:
427dcb4b 401 /* At this point, we have found some renames and copies and they
5098bafb 402 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 403 */
25d5ea41
JH
404 outq.queue = NULL;
405 outq.nr = outq.alloc = 0;
427dcb4b 406 for (i = 0; i < q->nr; i++) {
25d5ea41 407 struct diff_filepair *p = q->queue[i];
25d5ea41
JH
408 struct diff_filepair *pair_to_free = NULL;
409
2cd68882
JH
410 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
411 /*
412 * Creation
413 *
414 * We would output this create record if it has
415 * not been turned into a rename/copy already.
416 */
417 struct diff_rename_dst *dst =
418 locate_rename_dst(p->two, 0);
419 if (dst && dst->pair) {
25d5ea41
JH
420 diff_q(&outq, dst->pair);
421 pair_to_free = p;
422 }
423 else
2cd68882
JH
424 /* no matching rename/copy source, so
425 * record this as a creation.
25d5ea41
JH
426 */
427 diff_q(&outq, p);
427dcb4b 428 }
2cd68882
JH
429 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
430 /*
431 * Deletion
432 *
f345b0a0
JH
433 * We would output this delete record if:
434 *
435 * (1) this is a broken delete and the counterpart
436 * broken create remains in the output; or
5098bafb
JH
437 * (2) this is not a broken delete, and rename_dst
438 * does not have a rename/copy to move p->one->path
439 * out of existence.
f345b0a0
JH
440 *
441 * Otherwise, the counterpart broken create
442 * has been turned into a rename-edit; or
443 * delete did not have a matching create to
444 * begin with.
2cd68882 445 */
f345b0a0
JH
446 if (DIFF_PAIR_BROKEN(p)) {
447 /* broken delete */
448 struct diff_rename_dst *dst =
449 locate_rename_dst(p->one, 0);
450 if (dst && dst->pair)
451 /* counterpart is now rename/copy */
452 pair_to_free = p;
453 }
454 else {
5098bafb
JH
455 for (j = 0; j < rename_dst_nr; j++) {
456 if (!rename_dst[j].pair)
457 continue;
458 if (strcmp(rename_dst[j].pair->
459 one->path,
460 p->one->path))
461 continue;
462 break;
463 }
464 if (j < rename_dst_nr)
f345b0a0
JH
465 /* this path remains */
466 pair_to_free = p;
467 }
2cd68882
JH
468
469 if (pair_to_free)
470 ;
471 else
472 diff_q(&outq, p);
473 }
25d5ea41 474 else if (!diff_unmodified_pair(p))
15d061b4 475 /* all the usual ones need to be kept */
25d5ea41 476 diff_q(&outq, p);
15d061b4
JH
477 else
478 /* no need to keep unmodified pairs */
479 pair_to_free = p;
480
226406f6
JH
481 if (pair_to_free)
482 diff_free_filepair(pair_to_free);
427dcb4b 483 }
25d5ea41 484 diff_debug_queue("done copying original", &outq);
427dcb4b 485
25d5ea41
JH
486 free(q->queue);
487 *q = outq;
488 diff_debug_queue("done collapsing", q);
427dcb4b 489
6bac10d8
JH
490 /* We need to see which rename source really stays here;
491 * earlier we only checked if the path is left in the result,
492 * but even if a path remains in the result, if that is coming
493 * from copying something else on top of it, then the original
494 * source is lost and does not stay.
495 */
496 for (i = 0; i < q->nr; i++) {
497 struct diff_filepair *p = q->queue[i];
498 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
499 /* If one appears as the target of a rename-copy,
500 * then mark p->source_stays = 0; otherwise
501 * leave it as is.
502 */
503 p->source_stays = compute_stays(q, p->one);
504 }
505 }
506
5098bafb
JH
507 for (i = 0; i < rename_dst_nr; i++) {
508 diff_free_filespec_data(rename_dst[i].two);
509 free(rename_dst[i].two);
510 }
511
25d5ea41
JH
512 free(rename_dst);
513 rename_dst = NULL;
514 rename_dst_nr = rename_dst_alloc = 0;
515 free(rename_src);
516 rename_src = NULL;
517 rename_src_nr = rename_src_alloc = 0;
427dcb4b
JH
518 return;
519}