3 * Copyright (C) 2005 Junio C Hamano
8 #include "object-store.h"
11 #include "promisor-remote.h"
13 /* Table of rename/copy destinations */
15 static struct diff_rename_dst {
16 struct diff_filespec *two;
17 struct diff_filepair *pair;
19 static int rename_dst_nr, rename_dst_alloc;
21 static int find_rename_dst(struct diff_filespec *two)
27 while (last > first) {
28 int next = first + ((last - first) >> 1);
29 struct diff_rename_dst *dst = &(rename_dst[next]);
30 int cmp = strcmp(two->path, dst->two->path);
42 static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two)
44 int ofs = find_rename_dst(two);
45 return ofs < 0 ? NULL : &rename_dst[ofs];
49 * Returns 0 on success, -1 if we found a duplicate.
51 static int add_rename_dst(struct diff_filespec *two)
53 int first = find_rename_dst(two);
59 /* insert to make it at "first" */
60 ALLOC_GROW(rename_dst, rename_dst_nr + 1, rename_dst_alloc);
62 if (first < rename_dst_nr)
63 MOVE_ARRAY(rename_dst + first + 1, rename_dst + first,
64 rename_dst_nr - first - 1);
65 rename_dst[first].two = alloc_filespec(two->path);
66 fill_filespec(rename_dst[first].two, &two->oid, two->oid_valid,
68 rename_dst[first].pair = NULL;
72 /* Table of rename/copy src files */
73 static struct diff_rename_src {
74 struct diff_filepair *p;
75 unsigned short score; /* to remember the break score */
77 static int rename_src_nr, rename_src_alloc;
79 static struct diff_rename_src *register_rename_src(struct diff_filepair *p)
82 struct diff_filespec *one = p->one;
83 unsigned short score = p->score;
87 while (last > first) {
88 int next = first + ((last - first) >> 1);
89 struct diff_rename_src *src = &(rename_src[next]);
90 int cmp = strcmp(one->path, src->p->one->path);
100 /* insert to make it at "first" */
101 ALLOC_GROW(rename_src, rename_src_nr + 1, rename_src_alloc);
103 if (first < rename_src_nr)
104 MOVE_ARRAY(rename_src + first + 1, rename_src + first,
105 rename_src_nr - first - 1);
106 rename_src[first].p = p;
107 rename_src[first].score = score;
108 return &(rename_src[first]);
111 static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
113 int src_len = strlen(src->path), dst_len = strlen(dst->path);
114 while (src_len && dst_len) {
115 char c1 = src->path[--src_len];
116 char c2 = dst->path[--dst_len];
122 return (!src_len || src->path[src_len - 1] == '/') &&
123 (!dst_len || dst->path[dst_len - 1] == '/');
127 int src; /* index in rename_src */
128 int dst; /* index in rename_dst */
129 unsigned short score;
133 struct prefetch_options {
134 struct repository *repo;
137 static void prefetch(void *prefetch_options)
139 struct prefetch_options *options = prefetch_options;
141 struct oid_array to_fetch = OID_ARRAY_INIT;
143 for (i = 0; i < rename_dst_nr; i++) {
144 if (rename_dst[i].pair)
146 * The loop in diffcore_rename() will not need these
147 * blobs, so skip prefetching.
149 continue; /* already found exact match */
150 diff_add_if_missing(options->repo, &to_fetch,
153 for (i = 0; i < rename_src_nr; i++) {
154 if (options->skip_unmodified &&
155 diff_unmodified_pair(rename_src[i].p))
157 * The loop in diffcore_rename() will not need these
158 * blobs, so skip prefetching.
161 diff_add_if_missing(options->repo, &to_fetch,
162 rename_src[i].p->one);
164 promisor_remote_get_direct(options->repo, to_fetch.oid, to_fetch.nr);
165 oid_array_clear(&to_fetch);
168 static int estimate_similarity(struct repository *r,
169 struct diff_filespec *src,
170 struct diff_filespec *dst,
174 /* src points at a file that existed in the original tree (or
175 * optionally a file in the destination tree) and dst points
176 * at a newly created file. They may be quite similar, in which
177 * case we want to say src is renamed to dst or src is copied into
178 * dst, and then some edit has been applied to dst.
180 * Compare them and return how similar they are, representing
181 * the score as an integer between 0 and MAX_SCORE.
183 * When there is an exact match, it is considered a better
184 * match than anything else; the destination does not even
185 * call into this function in that case.
187 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
189 struct diff_populate_filespec_options dpf_options = {
192 struct prefetch_options prefetch_options = {r, skip_unmodified};
194 if (r == the_repository && has_promisor_remote()) {
195 dpf_options.missing_object_cb = prefetch;
196 dpf_options.missing_object_data = &prefetch_options;
199 /* We deal only with regular files. Symlink renames are handled
200 * only when they are exact matches --- in other words, no edits
203 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
207 * Need to check that source and destination sizes are
208 * filled in before comparing them.
210 * If we already have "cnt_data" filled in, we know it's
211 * all good (avoid checking the size for zero, as that
212 * is a possible size - we really should have a flag to
213 * say whether the size is valid or not!)
215 if (!src->cnt_data &&
216 diff_populate_filespec(r, src, &dpf_options))
218 if (!dst->cnt_data &&
219 diff_populate_filespec(r, dst, &dpf_options))
222 max_size = ((src->size > dst->size) ? src->size : dst->size);
223 base_size = ((src->size < dst->size) ? src->size : dst->size);
224 delta_size = max_size - base_size;
226 /* We would not consider edits that change the file size so
227 * drastically. delta_size must be smaller than
228 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
230 * Note that base_size == 0 case is handled here already
231 * and the final score computation below would not have a
232 * divide-by-zero issue.
234 if (max_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
237 dpf_options.check_size_only = 0;
239 if (!src->cnt_data && diff_populate_filespec(r, src, &dpf_options))
241 if (!dst->cnt_data && diff_populate_filespec(r, dst, &dpf_options))
244 if (diffcore_count_changes(r, src, dst,
245 &src->cnt_data, &dst->cnt_data,
246 &src_copied, &literal_added))
249 /* How similar are they?
250 * what percentage of material in dst are from source?
253 score = 0; /* should not happen */
255 score = (int)(src_copied * MAX_SCORE / max_size);
259 static void record_rename_pair(int dst_index, int src_index, int score)
261 struct diff_filespec *src, *dst;
262 struct diff_filepair *dp;
264 if (rename_dst[dst_index].pair)
265 die("internal error: dst already matched.");
267 src = rename_src[src_index].p->one;
271 dst = rename_dst[dst_index].two;
274 dp = diff_queue(NULL, src, dst);
275 dp->renamed_pair = 1;
276 if (!strcmp(src->path, dst->path))
277 dp->score = rename_src[src_index].score;
280 rename_dst[dst_index].pair = dp;
284 * We sort the rename similarity matrix with the score, in descending
285 * order (the most similar first).
287 static int score_compare(const void *a_, const void *b_)
289 const struct diff_score *a = a_, *b = b_;
291 /* sink the unused ones to the bottom */
293 return (0 <= b->dst);
297 if (a->score == b->score)
298 return b->name_score - a->name_score;
300 return b->score - a->score;
303 struct file_similarity {
304 struct hashmap_entry entry;
306 struct diff_filespec *filespec;
309 static unsigned int hash_filespec(struct repository *r,
310 struct diff_filespec *filespec)
312 if (!filespec->oid_valid) {
313 if (diff_populate_filespec(r, filespec, NULL))
315 hash_object_file(r->hash_algo, filespec->data, filespec->size,
316 "blob", &filespec->oid);
318 return oidhash(&filespec->oid);
321 static int find_identical_files(struct hashmap *srcs,
323 struct diff_options *options)
326 struct diff_filespec *target = rename_dst[dst_index].two;
327 struct file_similarity *p, *best = NULL;
328 int i = 100, best_score = -1;
329 unsigned int hash = hash_filespec(options->repo, target);
332 * Find the best source match for specified destination.
334 p = hashmap_get_entry_from_hash(srcs, hash, NULL,
335 struct file_similarity, entry);
336 hashmap_for_each_entry_from(srcs, p, entry) {
338 struct diff_filespec *source = p->filespec;
340 /* False hash collision? */
341 if (!oideq(&source->oid, &target->oid))
343 /* Non-regular files? If so, the modes must match! */
344 if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) {
345 if (source->mode != target->mode)
348 /* Give higher scores to sources that haven't been used already */
349 score = !source->rename_used;
350 if (source->rename_used && options->detect_rename != DIFF_DETECT_COPY)
352 score += basename_same(source, target);
353 if (score > best_score) {
360 /* Too many identical alternatives? Pick one */
365 record_rename_pair(dst_index, best->index, MAX_SCORE);
371 static void insert_file_table(struct repository *r,
372 struct hashmap *table, int index,
373 struct diff_filespec *filespec)
375 struct file_similarity *entry = xmalloc(sizeof(*entry));
377 entry->index = index;
378 entry->filespec = filespec;
380 hashmap_entry_init(&entry->entry, hash_filespec(r, filespec));
381 hashmap_add(table, &entry->entry);
385 * Find exact renames first.
387 * The first round matches up the up-to-date entries,
388 * and then during the second round we try to match
389 * cache-dirty entries as well.
391 static int find_exact_renames(struct diff_options *options)
394 struct hashmap file_table;
396 /* Add all sources to the hash table in reverse order, because
397 * later on they will be retrieved in LIFO order.
399 hashmap_init(&file_table, NULL, NULL, rename_src_nr);
400 for (i = rename_src_nr-1; i >= 0; i--)
401 insert_file_table(options->repo,
403 rename_src[i].p->one);
405 /* Walk the destinations and find best source match */
406 for (i = 0; i < rename_dst_nr; i++)
407 renames += find_identical_files(&file_table, i, options);
409 /* Free the hash data structure and entries */
410 hashmap_clear_and_free(&file_table, struct file_similarity, entry);
415 #define NUM_CANDIDATE_PER_DST 4
416 static void record_if_better(struct diff_score m[], struct diff_score *o)
420 /* find the worst one */
422 for (i = 1; i < NUM_CANDIDATE_PER_DST; i++)
423 if (score_compare(&m[i], &m[worst]) > 0)
426 /* is it better than the worst one? */
427 if (score_compare(&m[worst], o) > 0)
433 * 0 if we are under the limit;
434 * 1 if we need to disable inexact rename detection;
435 * 2 if we would be under the limit if we were given -C instead of -C -C.
437 static int too_many_rename_candidates(int num_destinations, int num_sources,
438 struct diff_options *options)
440 int rename_limit = options->rename_limit;
441 int i, limited_sources;
443 options->needed_rename_limit = 0;
446 * This basically does a test for the rename matrix not
447 * growing larger than a "rename_limit" square matrix, ie:
449 * num_destinations * num_sources > rename_limit * rename_limit
451 if (rename_limit <= 0)
452 rename_limit = 32767;
453 if ((num_destinations <= rename_limit || num_sources <= rename_limit) &&
454 ((uint64_t)num_destinations * (uint64_t)num_sources
455 <= (uint64_t)rename_limit * (uint64_t)rename_limit))
458 options->needed_rename_limit =
459 num_sources > num_destinations ? num_sources : num_destinations;
461 /* Are we running under -C -C? */
462 if (!options->flags.find_copies_harder)
465 /* Would we bust the limit if we were running under -C? */
466 for (limited_sources = i = 0; i < num_sources; i++) {
467 if (diff_unmodified_pair(rename_src[i].p))
471 if ((num_destinations <= rename_limit || limited_sources <= rename_limit) &&
472 ((uint64_t)num_destinations * (uint64_t)limited_sources
473 <= (uint64_t)rename_limit * (uint64_t)rename_limit))
478 static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, int copies)
482 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
483 struct diff_rename_dst *dst;
485 if ((mx[i].dst < 0) ||
486 (mx[i].score < minimum_score))
487 break; /* there is no more usable pair. */
488 dst = &rename_dst[mx[i].dst];
490 continue; /* already done, either exact or fuzzy. */
491 if (!copies && rename_src[mx[i].src].p->one->rename_used)
493 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
499 void diffcore_rename(struct diff_options *options)
501 int detect_rename = options->detect_rename;
502 int minimum_score = options->rename_score;
503 struct diff_queue_struct *q = &diff_queued_diff;
504 struct diff_queue_struct outq;
505 struct diff_score *mx;
506 int i, j, rename_count, skip_unmodified = 0;
507 int num_destinations, dst_cnt;
508 struct progress *progress = NULL;
511 minimum_score = DEFAULT_RENAME_SCORE;
513 for (i = 0; i < q->nr; i++) {
514 struct diff_filepair *p = q->queue[i];
515 if (!DIFF_FILE_VALID(p->one)) {
516 if (!DIFF_FILE_VALID(p->two))
517 continue; /* unmerged */
518 else if (options->single_follow &&
519 strcmp(options->single_follow, p->two->path))
520 continue; /* not interested */
521 else if (!options->flags.rename_empty &&
522 is_empty_blob_oid(&p->two->oid))
524 else if (add_rename_dst(p->two) < 0) {
525 warning("skipping rename detection, detected"
526 " duplicate destination '%s'",
531 else if (!options->flags.rename_empty &&
532 is_empty_blob_oid(&p->one->oid))
534 else if (!DIFF_PAIR_UNMERGED(p) && !DIFF_FILE_VALID(p->two)) {
536 * If the source is a broken "delete", and
537 * they did not really want to get broken,
538 * that means the source actually stays.
539 * So we increment the "rename_used" score
540 * by one, to indicate ourselves as a user
542 if (p->broken_pair && !p->score)
543 p->one->rename_used++;
544 register_rename_src(p);
546 else if (detect_rename == DIFF_DETECT_COPY) {
548 * Increment the "rename_used" score by
549 * one, to indicate ourselves as a user.
551 p->one->rename_used++;
552 register_rename_src(p);
555 if (rename_dst_nr == 0 || rename_src_nr == 0)
556 goto cleanup; /* nothing to do */
559 * We really want to cull the candidates list early
560 * with cheap tests in order to avoid doing deltas.
562 rename_count = find_exact_renames(options);
564 /* Did we only want exact renames? */
565 if (minimum_score == MAX_SCORE)
569 * Calculate how many renames are left (but all the source
570 * files still remain as options for rename/copies!)
572 num_destinations = (rename_dst_nr - rename_count);
575 if (!num_destinations)
578 switch (too_many_rename_candidates(num_destinations, rename_src_nr,
583 options->degraded_cc_to_c = 1;
590 if (options->show_rename_progress) {
591 progress = start_delayed_progress(
592 _("Performing inexact rename detection"),
593 (uint64_t)rename_dst_nr * (uint64_t)rename_src_nr);
596 mx = xcalloc(st_mult(NUM_CANDIDATE_PER_DST, num_destinations),
598 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
599 struct diff_filespec *two = rename_dst[i].two;
600 struct diff_score *m;
602 if (rename_dst[i].pair)
603 continue; /* dealt with exact match already. */
605 m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST];
606 for (j = 0; j < NUM_CANDIDATE_PER_DST; j++)
609 for (j = 0; j < rename_src_nr; j++) {
610 struct diff_filespec *one = rename_src[j].p->one;
611 struct diff_score this_src;
613 if (skip_unmodified &&
614 diff_unmodified_pair(rename_src[j].p))
617 this_src.score = estimate_similarity(options->repo,
621 this_src.name_score = basename_same(one, two);
624 record_if_better(m, &this_src);
626 * Once we run estimate_similarity,
627 * We do not need the text anymore.
629 diff_free_filespec_blob(one);
630 diff_free_filespec_blob(two);
633 display_progress(progress, (uint64_t)(i+1)*(uint64_t)rename_src_nr);
635 stop_progress(&progress);
637 /* cost matrix sorted by most to least similar pair */
638 STABLE_QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare);
640 rename_count += find_renames(mx, dst_cnt, minimum_score, 0);
641 if (detect_rename == DIFF_DETECT_COPY)
642 rename_count += find_renames(mx, dst_cnt, minimum_score, 1);
646 /* At this point, we have found some renames and copies and they
647 * are recorded in rename_dst. The original list is still in *q.
649 DIFF_QUEUE_CLEAR(&outq);
650 for (i = 0; i < q->nr; i++) {
651 struct diff_filepair *p = q->queue[i];
652 struct diff_filepair *pair_to_free = NULL;
654 if (DIFF_PAIR_UNMERGED(p)) {
657 else if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
661 * We would output this create record if it has
662 * not been turned into a rename/copy already.
664 struct diff_rename_dst *dst = locate_rename_dst(p->two);
665 if (dst && dst->pair) {
666 diff_q(&outq, dst->pair);
670 /* no matching rename/copy source, so
671 * record this as a creation.
675 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
679 * We would output this delete record if:
681 * (1) this is a broken delete and the counterpart
682 * broken create remains in the output; or
683 * (2) this is not a broken delete, and rename_dst
684 * does not have a rename/copy to move p->one->path
687 * Otherwise, the counterpart broken create
688 * has been turned into a rename-edit; or
689 * delete did not have a matching create to
692 if (DIFF_PAIR_BROKEN(p)) {
694 struct diff_rename_dst *dst = locate_rename_dst(p->one);
695 if (dst && dst->pair)
696 /* counterpart is now rename/copy */
700 if (p->one->rename_used)
701 /* this path remains */
710 else if (!diff_unmodified_pair(p))
711 /* all the usual ones need to be kept */
714 /* no need to keep unmodified pairs */
718 diff_free_filepair(pair_to_free);
720 diff_debug_queue("done copying original", &outq);
724 diff_debug_queue("done collapsing", q);
726 for (i = 0; i < rename_dst_nr; i++)
727 free_filespec(rename_dst[i].two);
729 FREE_AND_NULL(rename_dst);
730 rename_dst_nr = rename_dst_alloc = 0;
731 FREE_AND_NULL(rename_src);
732 rename_src_nr = rename_src_alloc = 0;