mingw: safe-guard a bit more against getenv() problems
[git.git] / diffcore-rename.c
blob07bd34b63145e1dc179afebcc7af351c34c2ab07
1 /*
2 * Copyright (C) 2005 Junio C Hamano
3 */
4 #include "cache.h"
5 #include "diff.h"
6 #include "diffcore.h"
7 #include "object-store.h"
8 #include "hashmap.h"
9 #include "progress.h"
11 /* Table of rename/copy destinations */
13 static struct diff_rename_dst {
14 struct diff_filespec *two;
15 struct diff_filepair *pair;
16 } *rename_dst;
17 static int rename_dst_nr, rename_dst_alloc;
19 static int find_rename_dst(struct diff_filespec *two)
21 int first, last;
23 first = 0;
24 last = rename_dst_nr;
25 while (last > first) {
26 int next = (last + first) >> 1;
27 struct diff_rename_dst *dst = &(rename_dst[next]);
28 int cmp = strcmp(two->path, dst->two->path);
29 if (!cmp)
30 return next;
31 if (cmp < 0) {
32 last = next;
33 continue;
35 first = next+1;
37 return -first - 1;
40 static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two)
42 int ofs = find_rename_dst(two);
43 return ofs < 0 ? NULL : &rename_dst[ofs];
47 * Returns 0 on success, -1 if we found a duplicate.
49 static int add_rename_dst(struct diff_filespec *two)
51 int first = find_rename_dst(two);
53 if (first >= 0)
54 return -1;
55 first = -first - 1;
57 /* insert to make it at "first" */
58 ALLOC_GROW(rename_dst, rename_dst_nr + 1, rename_dst_alloc);
59 rename_dst_nr++;
60 if (first < rename_dst_nr)
61 MOVE_ARRAY(rename_dst + first + 1, rename_dst + first,
62 rename_dst_nr - first - 1);
63 rename_dst[first].two = alloc_filespec(two->path);
64 fill_filespec(rename_dst[first].two, &two->oid, two->oid_valid,
65 two->mode);
66 rename_dst[first].pair = NULL;
67 return 0;
70 /* Table of rename/copy src files */
71 static struct diff_rename_src {
72 struct diff_filepair *p;
73 unsigned short score; /* to remember the break score */
74 } *rename_src;
75 static int rename_src_nr, rename_src_alloc;
77 static struct diff_rename_src *register_rename_src(struct diff_filepair *p)
79 int first, last;
80 struct diff_filespec *one = p->one;
81 unsigned short score = p->score;
83 first = 0;
84 last = rename_src_nr;
85 while (last > first) {
86 int next = (last + first) >> 1;
87 struct diff_rename_src *src = &(rename_src[next]);
88 int cmp = strcmp(one->path, src->p->one->path);
89 if (!cmp)
90 return src;
91 if (cmp < 0) {
92 last = next;
93 continue;
95 first = next+1;
98 /* insert to make it at "first" */
99 ALLOC_GROW(rename_src, rename_src_nr + 1, rename_src_alloc);
100 rename_src_nr++;
101 if (first < rename_src_nr)
102 MOVE_ARRAY(rename_src + first + 1, rename_src + first,
103 rename_src_nr - first - 1);
104 rename_src[first].p = p;
105 rename_src[first].score = score;
106 return &(rename_src[first]);
109 static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
111 int src_len = strlen(src->path), dst_len = strlen(dst->path);
112 while (src_len && dst_len) {
113 char c1 = src->path[--src_len];
114 char c2 = dst->path[--dst_len];
115 if (c1 != c2)
116 return 0;
117 if (c1 == '/')
118 return 1;
120 return (!src_len || src->path[src_len - 1] == '/') &&
121 (!dst_len || dst->path[dst_len - 1] == '/');
124 struct diff_score {
125 int src; /* index in rename_src */
126 int dst; /* index in rename_dst */
127 unsigned short score;
128 short name_score;
131 static int estimate_similarity(struct repository *r,
132 struct diff_filespec *src,
133 struct diff_filespec *dst,
134 int minimum_score)
136 /* src points at a file that existed in the original tree (or
137 * optionally a file in the destination tree) and dst points
138 * at a newly created file. They may be quite similar, in which
139 * case we want to say src is renamed to dst or src is copied into
140 * dst, and then some edit has been applied to dst.
142 * Compare them and return how similar they are, representing
143 * the score as an integer between 0 and MAX_SCORE.
145 * When there is an exact match, it is considered a better
146 * match than anything else; the destination does not even
147 * call into this function in that case.
149 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
150 int score;
152 /* We deal only with regular files. Symlink renames are handled
153 * only when they are exact matches --- in other words, no edits
154 * after renaming.
156 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
157 return 0;
160 * Need to check that source and destination sizes are
161 * filled in before comparing them.
163 * If we already have "cnt_data" filled in, we know it's
164 * all good (avoid checking the size for zero, as that
165 * is a possible size - we really should have a flag to
166 * say whether the size is valid or not!)
168 if (!src->cnt_data &&
169 diff_populate_filespec(r, src, CHECK_SIZE_ONLY))
170 return 0;
171 if (!dst->cnt_data &&
172 diff_populate_filespec(r, dst, CHECK_SIZE_ONLY))
173 return 0;
175 max_size = ((src->size > dst->size) ? src->size : dst->size);
176 base_size = ((src->size < dst->size) ? src->size : dst->size);
177 delta_size = max_size - base_size;
179 /* We would not consider edits that change the file size so
180 * drastically. delta_size must be smaller than
181 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
183 * Note that base_size == 0 case is handled here already
184 * and the final score computation below would not have a
185 * divide-by-zero issue.
187 if (max_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
188 return 0;
190 if (!src->cnt_data && diff_populate_filespec(r, src, 0))
191 return 0;
192 if (!dst->cnt_data && diff_populate_filespec(r, dst, 0))
193 return 0;
195 if (diffcore_count_changes(r, src, dst,
196 &src->cnt_data, &dst->cnt_data,
197 &src_copied, &literal_added))
198 return 0;
200 /* How similar are they?
201 * what percentage of material in dst are from source?
203 if (!dst->size)
204 score = 0; /* should not happen */
205 else
206 score = (int)(src_copied * MAX_SCORE / max_size);
207 return score;
210 static void record_rename_pair(int dst_index, int src_index, int score)
212 struct diff_filespec *src, *dst;
213 struct diff_filepair *dp;
215 if (rename_dst[dst_index].pair)
216 die("internal error: dst already matched.");
218 src = rename_src[src_index].p->one;
219 src->rename_used++;
220 src->count++;
222 dst = rename_dst[dst_index].two;
223 dst->count++;
225 dp = diff_queue(NULL, src, dst);
226 dp->renamed_pair = 1;
227 if (!strcmp(src->path, dst->path))
228 dp->score = rename_src[src_index].score;
229 else
230 dp->score = score;
231 rename_dst[dst_index].pair = dp;
235 * We sort the rename similarity matrix with the score, in descending
236 * order (the most similar first).
238 static int score_compare(const void *a_, const void *b_)
240 const struct diff_score *a = a_, *b = b_;
242 /* sink the unused ones to the bottom */
243 if (a->dst < 0)
244 return (0 <= b->dst);
245 else if (b->dst < 0)
246 return -1;
248 if (a->score == b->score)
249 return b->name_score - a->name_score;
251 return b->score - a->score;
254 struct file_similarity {
255 struct hashmap_entry entry;
256 int index;
257 struct diff_filespec *filespec;
260 static unsigned int hash_filespec(struct repository *r,
261 struct diff_filespec *filespec)
263 if (!filespec->oid_valid) {
264 if (diff_populate_filespec(r, filespec, 0))
265 return 0;
266 hash_object_file(filespec->data, filespec->size, "blob",
267 &filespec->oid);
269 return sha1hash(filespec->oid.hash);
272 static int find_identical_files(struct hashmap *srcs,
273 int dst_index,
274 struct diff_options *options)
276 int renames = 0;
278 struct diff_filespec *target = rename_dst[dst_index].two;
279 struct file_similarity *p, *best = NULL;
280 int i = 100, best_score = -1;
283 * Find the best source match for specified destination.
285 p = hashmap_get_from_hash(srcs,
286 hash_filespec(options->repo, target),
287 NULL);
288 for (; p; p = hashmap_get_next(srcs, p)) {
289 int score;
290 struct diff_filespec *source = p->filespec;
292 /* False hash collision? */
293 if (!oideq(&source->oid, &target->oid))
294 continue;
295 /* Non-regular files? If so, the modes must match! */
296 if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) {
297 if (source->mode != target->mode)
298 continue;
300 /* Give higher scores to sources that haven't been used already */
301 score = !source->rename_used;
302 if (source->rename_used && options->detect_rename != DIFF_DETECT_COPY)
303 continue;
304 score += basename_same(source, target);
305 if (score > best_score) {
306 best = p;
307 best_score = score;
308 if (score == 2)
309 break;
312 /* Too many identical alternatives? Pick one */
313 if (!--i)
314 break;
316 if (best) {
317 record_rename_pair(dst_index, best->index, MAX_SCORE);
318 renames++;
320 return renames;
323 static void insert_file_table(struct repository *r,
324 struct hashmap *table, int index,
325 struct diff_filespec *filespec)
327 struct file_similarity *entry = xmalloc(sizeof(*entry));
329 entry->index = index;
330 entry->filespec = filespec;
332 hashmap_entry_init(entry, hash_filespec(r, filespec));
333 hashmap_add(table, entry);
337 * Find exact renames first.
339 * The first round matches up the up-to-date entries,
340 * and then during the second round we try to match
341 * cache-dirty entries as well.
343 static int find_exact_renames(struct diff_options *options)
345 int i, renames = 0;
346 struct hashmap file_table;
348 /* Add all sources to the hash table in reverse order, because
349 * later on they will be retrieved in LIFO order.
351 hashmap_init(&file_table, NULL, NULL, rename_src_nr);
352 for (i = rename_src_nr-1; i >= 0; i--)
353 insert_file_table(options->repo,
354 &file_table, i,
355 rename_src[i].p->one);
357 /* Walk the destinations and find best source match */
358 for (i = 0; i < rename_dst_nr; i++)
359 renames += find_identical_files(&file_table, i, options);
361 /* Free the hash data structure and entries */
362 hashmap_free(&file_table, 1);
364 return renames;
367 #define NUM_CANDIDATE_PER_DST 4
368 static void record_if_better(struct diff_score m[], struct diff_score *o)
370 int i, worst;
372 /* find the worst one */
373 worst = 0;
374 for (i = 1; i < NUM_CANDIDATE_PER_DST; i++)
375 if (score_compare(&m[i], &m[worst]) > 0)
376 worst = i;
378 /* is it better than the worst one? */
379 if (score_compare(&m[worst], o) > 0)
380 m[worst] = *o;
384 * Returns:
385 * 0 if we are under the limit;
386 * 1 if we need to disable inexact rename detection;
387 * 2 if we would be under the limit if we were given -C instead of -C -C.
389 static int too_many_rename_candidates(int num_create,
390 struct diff_options *options)
392 int rename_limit = options->rename_limit;
393 int num_src = rename_src_nr;
394 int i;
396 options->needed_rename_limit = 0;
399 * This basically does a test for the rename matrix not
400 * growing larger than a "rename_limit" square matrix, ie:
402 * num_create * num_src > rename_limit * rename_limit
404 if (rename_limit <= 0)
405 rename_limit = 32767;
406 if ((num_create <= rename_limit || num_src <= rename_limit) &&
407 ((uint64_t)num_create * (uint64_t)num_src
408 <= (uint64_t)rename_limit * (uint64_t)rename_limit))
409 return 0;
411 options->needed_rename_limit =
412 num_src > num_create ? num_src : num_create;
414 /* Are we running under -C -C? */
415 if (!options->flags.find_copies_harder)
416 return 1;
418 /* Would we bust the limit if we were running under -C? */
419 for (num_src = i = 0; i < rename_src_nr; i++) {
420 if (diff_unmodified_pair(rename_src[i].p))
421 continue;
422 num_src++;
424 if ((num_create <= rename_limit || num_src <= rename_limit) &&
425 ((uint64_t)num_create * (uint64_t)num_src
426 <= (uint64_t)rename_limit * (uint64_t)rename_limit))
427 return 2;
428 return 1;
431 static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, int copies)
433 int count = 0, i;
435 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
436 struct diff_rename_dst *dst;
438 if ((mx[i].dst < 0) ||
439 (mx[i].score < minimum_score))
440 break; /* there is no more usable pair. */
441 dst = &rename_dst[mx[i].dst];
442 if (dst->pair)
443 continue; /* already done, either exact or fuzzy. */
444 if (!copies && rename_src[mx[i].src].p->one->rename_used)
445 continue;
446 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
447 count++;
449 return count;
452 void diffcore_rename(struct diff_options *options)
454 int detect_rename = options->detect_rename;
455 int minimum_score = options->rename_score;
456 struct diff_queue_struct *q = &diff_queued_diff;
457 struct diff_queue_struct outq;
458 struct diff_score *mx;
459 int i, j, rename_count, skip_unmodified = 0;
460 int num_create, dst_cnt;
461 struct progress *progress = NULL;
463 if (!minimum_score)
464 minimum_score = DEFAULT_RENAME_SCORE;
466 for (i = 0; i < q->nr; i++) {
467 struct diff_filepair *p = q->queue[i];
468 if (!DIFF_FILE_VALID(p->one)) {
469 if (!DIFF_FILE_VALID(p->two))
470 continue; /* unmerged */
471 else if (options->single_follow &&
472 strcmp(options->single_follow, p->two->path))
473 continue; /* not interested */
474 else if (!options->flags.rename_empty &&
475 is_empty_blob_oid(&p->two->oid))
476 continue;
477 else if (add_rename_dst(p->two) < 0) {
478 warning("skipping rename detection, detected"
479 " duplicate destination '%s'",
480 p->two->path);
481 goto cleanup;
484 else if (!options->flags.rename_empty &&
485 is_empty_blob_oid(&p->one->oid))
486 continue;
487 else if (!DIFF_PAIR_UNMERGED(p) && !DIFF_FILE_VALID(p->two)) {
489 * If the source is a broken "delete", and
490 * they did not really want to get broken,
491 * that means the source actually stays.
492 * So we increment the "rename_used" score
493 * by one, to indicate ourselves as a user
495 if (p->broken_pair && !p->score)
496 p->one->rename_used++;
497 register_rename_src(p);
499 else if (detect_rename == DIFF_DETECT_COPY) {
501 * Increment the "rename_used" score by
502 * one, to indicate ourselves as a user.
504 p->one->rename_used++;
505 register_rename_src(p);
508 if (rename_dst_nr == 0 || rename_src_nr == 0)
509 goto cleanup; /* nothing to do */
512 * We really want to cull the candidates list early
513 * with cheap tests in order to avoid doing deltas.
515 rename_count = find_exact_renames(options);
517 /* Did we only want exact renames? */
518 if (minimum_score == MAX_SCORE)
519 goto cleanup;
522 * Calculate how many renames are left (but all the source
523 * files still remain as options for rename/copies!)
525 num_create = (rename_dst_nr - rename_count);
527 /* All done? */
528 if (!num_create)
529 goto cleanup;
531 switch (too_many_rename_candidates(num_create, options)) {
532 case 1:
533 goto cleanup;
534 case 2:
535 options->degraded_cc_to_c = 1;
536 skip_unmodified = 1;
537 break;
538 default:
539 break;
542 if (options->show_rename_progress) {
543 progress = start_delayed_progress(
544 _("Performing inexact rename detection"),
545 (uint64_t)rename_dst_nr * (uint64_t)rename_src_nr);
548 mx = xcalloc(st_mult(NUM_CANDIDATE_PER_DST, num_create), sizeof(*mx));
549 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
550 struct diff_filespec *two = rename_dst[i].two;
551 struct diff_score *m;
553 if (rename_dst[i].pair)
554 continue; /* dealt with exact match already. */
556 m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST];
557 for (j = 0; j < NUM_CANDIDATE_PER_DST; j++)
558 m[j].dst = -1;
560 for (j = 0; j < rename_src_nr; j++) {
561 struct diff_filespec *one = rename_src[j].p->one;
562 struct diff_score this_src;
564 if (skip_unmodified &&
565 diff_unmodified_pair(rename_src[j].p))
566 continue;
568 this_src.score = estimate_similarity(options->repo,
569 one, two,
570 minimum_score);
571 this_src.name_score = basename_same(one, two);
572 this_src.dst = i;
573 this_src.src = j;
574 record_if_better(m, &this_src);
576 * Once we run estimate_similarity,
577 * We do not need the text anymore.
579 diff_free_filespec_blob(one);
580 diff_free_filespec_blob(two);
582 dst_cnt++;
583 display_progress(progress, (uint64_t)(i+1)*(uint64_t)rename_src_nr);
585 stop_progress(&progress);
587 /* cost matrix sorted by most to least similar pair */
588 QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare);
590 rename_count += find_renames(mx, dst_cnt, minimum_score, 0);
591 if (detect_rename == DIFF_DETECT_COPY)
592 rename_count += find_renames(mx, dst_cnt, minimum_score, 1);
593 free(mx);
595 cleanup:
596 /* At this point, we have found some renames and copies and they
597 * are recorded in rename_dst. The original list is still in *q.
599 DIFF_QUEUE_CLEAR(&outq);
600 for (i = 0; i < q->nr; i++) {
601 struct diff_filepair *p = q->queue[i];
602 struct diff_filepair *pair_to_free = NULL;
604 if (DIFF_PAIR_UNMERGED(p)) {
605 diff_q(&outq, p);
607 else if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
609 * Creation
611 * We would output this create record if it has
612 * not been turned into a rename/copy already.
614 struct diff_rename_dst *dst = locate_rename_dst(p->two);
615 if (dst && dst->pair) {
616 diff_q(&outq, dst->pair);
617 pair_to_free = p;
619 else
620 /* no matching rename/copy source, so
621 * record this as a creation.
623 diff_q(&outq, p);
625 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
627 * Deletion
629 * We would output this delete record if:
631 * (1) this is a broken delete and the counterpart
632 * broken create remains in the output; or
633 * (2) this is not a broken delete, and rename_dst
634 * does not have a rename/copy to move p->one->path
635 * out of existence.
637 * Otherwise, the counterpart broken create
638 * has been turned into a rename-edit; or
639 * delete did not have a matching create to
640 * begin with.
642 if (DIFF_PAIR_BROKEN(p)) {
643 /* broken delete */
644 struct diff_rename_dst *dst = locate_rename_dst(p->one);
645 if (dst && dst->pair)
646 /* counterpart is now rename/copy */
647 pair_to_free = p;
649 else {
650 if (p->one->rename_used)
651 /* this path remains */
652 pair_to_free = p;
655 if (pair_to_free)
657 else
658 diff_q(&outq, p);
660 else if (!diff_unmodified_pair(p))
661 /* all the usual ones need to be kept */
662 diff_q(&outq, p);
663 else
664 /* no need to keep unmodified pairs */
665 pair_to_free = p;
667 if (pair_to_free)
668 diff_free_filepair(pair_to_free);
670 diff_debug_queue("done copying original", &outq);
672 free(q->queue);
673 *q = outq;
674 diff_debug_queue("done collapsing", q);
676 for (i = 0; i < rename_dst_nr; i++)
677 free_filespec(rename_dst[i].two);
679 FREE_AND_NULL(rename_dst);
680 rename_dst_nr = rename_dst_alloc = 0;
681 FREE_AND_NULL(rename_src);
682 rename_src_nr = rename_src_alloc = 0;
683 return;