Makefile: customization for supporting HP-UX
[git/fastimport.git] / diffcore-rename.c
blob3d377251bef8ea843b7a7fa41f98d611daecbcc1
1 /*
2 * Copyright (C) 2005 Junio C Hamano
3 */
4 #include "cache.h"
5 #include "diff.h"
6 #include "diffcore.h"
7 #include "hash.h"
9 /* Table of rename/copy destinations */
11 static struct diff_rename_dst {
12 struct diff_filespec *two;
13 struct diff_filepair *pair;
14 } *rename_dst;
15 static int rename_dst_nr, rename_dst_alloc;
17 static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
18 int insert_ok)
20 int first, last;
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;
34 first = next+1;
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));
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));
49 rename_dst[first].two = alloc_filespec(two->path);
50 fill_filespec(rename_dst[first].two, two->sha1, two->mode);
51 rename_dst[first].pair = NULL;
52 return &(rename_dst[first]);
55 /* Table of rename/copy src files */
56 static struct diff_rename_src {
57 struct diff_filespec *one;
58 unsigned short score; /* to remember the break score */
59 } *rename_src;
60 static int rename_src_nr, rename_src_alloc;
62 static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
63 unsigned short score)
65 int first, last;
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;
79 first = next+1;
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));
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;
93 rename_src[first].score = score;
94 return &(rename_src[first]);
97 static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
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;
108 return (!src_len || src->path[src_len - 1] == '/') &&
109 (!dst_len || dst->path[dst_len - 1] == '/');
112 struct diff_score {
113 int src; /* index in rename_src */
114 int dst; /* index in rename_dst */
115 int score;
116 int name_score;
119 static int estimate_similarity(struct diff_filespec *src,
120 struct diff_filespec *dst,
121 int minimum_score)
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.
129 * Compare them and return how similar they are, representing
130 * the score as an integer between 0 and MAX_SCORE.
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.
136 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
137 unsigned long delta_limit;
138 int score;
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.
144 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
145 return 0;
148 * Need to check that source and destination sizes are
149 * filled in before comparing them.
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!)
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;
161 max_size = ((src->size > dst->size) ? src->size : dst->size);
162 base_size = ((src->size < dst->size) ? src->size : dst->size);
163 delta_size = max_size - base_size;
165 /* We would not consider edits that change the file size so
166 * drastically. delta_size must be smaller than
167 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
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.
173 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
174 return 0;
176 delta_limit = (unsigned long)
177 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
178 if (diffcore_count_changes(src, dst,
179 &src->cnt_data, &dst->cnt_data,
180 delta_limit,
181 &src_copied, &literal_added))
182 return 0;
184 /* How similar are they?
185 * what percentage of material in dst are from source?
187 if (!dst->size)
188 score = 0; /* should not happen */
189 else
190 score = (int)(src_copied * MAX_SCORE / max_size);
191 return score;
194 static void record_rename_pair(int dst_index, int src_index, int score)
196 struct diff_filespec *src, *dst;
197 struct diff_filepair *dp;
199 if (rename_dst[dst_index].pair)
200 die("internal error: dst already matched.");
202 src = rename_src[src_index].one;
203 src->rename_used++;
204 src->count++;
206 dst = rename_dst[dst_index].two;
207 dst->count++;
209 dp = diff_queue(NULL, src, dst);
210 dp->renamed_pair = 1;
211 if (!strcmp(src->path, dst->path))
212 dp->score = rename_src[src_index].score;
213 else
214 dp->score = score;
215 rename_dst[dst_index].pair = dp;
219 * We sort the rename similarity matrix with the score, in descending
220 * order (the most similar first).
222 static int score_compare(const void *a_, const void *b_)
224 const struct diff_score *a = a_, *b = b_;
226 if (a->score == b->score)
227 return b->name_score - a->name_score;
229 return b->score - a->score;
232 struct file_similarity {
233 int src_dst, index;
234 struct diff_filespec *filespec;
235 struct file_similarity *next;
238 static int find_identical_files(struct file_similarity *src,
239 struct file_similarity *dst)
241 int renames = 0;
244 * Walk over all the destinations ...
246 do {
247 struct diff_filespec *target = dst->filespec;
248 struct file_similarity *p, *best;
249 int i = 100, best_score = -1;
252 * .. to find the best source match
254 best = NULL;
255 for (p = src; p; p = p->next) {
256 int score;
257 struct diff_filespec *source = p->filespec;
259 /* False hash collission? */
260 if (hashcmp(source->sha1, target->sha1))
261 continue;
262 /* Non-regular files? If so, the modes must match! */
263 if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) {
264 if (source->mode != target->mode)
265 continue;
267 /* Give higher scores to sources that haven't been used already */
268 score = !source->rename_used;
269 score += basename_same(source, target);
270 if (score > best_score) {
271 best = p;
272 best_score = score;
273 if (score == 2)
274 break;
277 /* Too many identical alternatives? Pick one */
278 if (!--i)
279 break;
281 if (best) {
282 record_rename_pair(dst->index, best->index, MAX_SCORE);
283 renames++;
285 } while ((dst = dst->next) != NULL);
286 return renames;
289 static void free_similarity_list(struct file_similarity *p)
291 while (p) {
292 struct file_similarity *entry = p;
293 p = p->next;
294 free(entry);
298 static int find_same_files(void *ptr)
300 int ret;
301 struct file_similarity *p = ptr;
302 struct file_similarity *src = NULL, *dst = NULL;
304 /* Split the hash list up into sources and destinations */
305 do {
306 struct file_similarity *entry = p;
307 p = p->next;
308 if (entry->src_dst < 0) {
309 entry->next = src;
310 src = entry;
311 } else {
312 entry->next = dst;
313 dst = entry;
315 } while (p);
318 * If we have both sources *and* destinations, see if
319 * we can match them up
321 ret = (src && dst) ? find_identical_files(src, dst) : 0;
323 /* Free the hashes and return the number of renames found */
324 free_similarity_list(src);
325 free_similarity_list(dst);
326 return ret;
329 static unsigned int hash_filespec(struct diff_filespec *filespec)
331 unsigned int hash;
332 if (!filespec->sha1_valid) {
333 if (diff_populate_filespec(filespec, 0))
334 return 0;
335 hash_sha1_file(filespec->data, filespec->size, "blob", filespec->sha1);
337 memcpy(&hash, filespec->sha1, sizeof(hash));
338 return hash;
341 static void insert_file_table(struct hash_table *table, int src_dst, int index, struct diff_filespec *filespec)
343 void **pos;
344 unsigned int hash;
345 struct file_similarity *entry = xmalloc(sizeof(*entry));
347 entry->src_dst = src_dst;
348 entry->index = index;
349 entry->filespec = filespec;
350 entry->next = NULL;
352 hash = hash_filespec(filespec);
353 pos = insert_hash(hash, entry, table);
355 /* We already had an entry there? */
356 if (pos) {
357 entry->next = *pos;
358 *pos = entry;
363 * Find exact renames first.
365 * The first round matches up the up-to-date entries,
366 * and then during the second round we try to match
367 * cache-dirty entries as well.
369 static int find_exact_renames(void)
371 int i;
372 struct hash_table file_table;
374 init_hash(&file_table);
375 for (i = 0; i < rename_src_nr; i++)
376 insert_file_table(&file_table, -1, i, rename_src[i].one);
378 for (i = 0; i < rename_dst_nr; i++)
379 insert_file_table(&file_table, 1, i, rename_dst[i].two);
381 /* Find the renames */
382 i = for_each_hash(&file_table, find_same_files);
384 /* .. and free the hash data structure */
385 free_hash(&file_table);
387 return i;
390 void diffcore_rename(struct diff_options *options)
392 int detect_rename = options->detect_rename;
393 int minimum_score = options->rename_score;
394 int rename_limit = options->rename_limit;
395 struct diff_queue_struct *q = &diff_queued_diff;
396 struct diff_queue_struct outq;
397 struct diff_score *mx;
398 int i, j, rename_count;
399 int num_create, num_src, dst_cnt;
401 if (!minimum_score)
402 minimum_score = DEFAULT_RENAME_SCORE;
404 for (i = 0; i < q->nr; i++) {
405 struct diff_filepair *p = q->queue[i];
406 if (!DIFF_FILE_VALID(p->one)) {
407 if (!DIFF_FILE_VALID(p->two))
408 continue; /* unmerged */
409 else if (options->single_follow &&
410 strcmp(options->single_follow, p->two->path))
411 continue; /* not interested */
412 else
413 locate_rename_dst(p->two, 1);
415 else if (!DIFF_FILE_VALID(p->two)) {
417 * If the source is a broken "delete", and
418 * they did not really want to get broken,
419 * that means the source actually stays.
420 * So we increment the "rename_used" score
421 * by one, to indicate ourselves as a user
423 if (p->broken_pair && !p->score)
424 p->one->rename_used++;
425 register_rename_src(p->one, p->score);
427 else if (detect_rename == DIFF_DETECT_COPY) {
429 * Increment the "rename_used" score by
430 * one, to indicate ourselves as a user.
432 p->one->rename_used++;
433 register_rename_src(p->one, p->score);
436 if (rename_dst_nr == 0 || rename_src_nr == 0)
437 goto cleanup; /* nothing to do */
440 * We really want to cull the candidates list early
441 * with cheap tests in order to avoid doing deltas.
443 rename_count = find_exact_renames();
445 /* Did we only want exact renames? */
446 if (minimum_score == MAX_SCORE)
447 goto cleanup;
450 * Calculate how many renames are left (but all the source
451 * files still remain as options for rename/copies!)
453 num_create = (rename_dst_nr - rename_count);
454 num_src = rename_src_nr;
456 /* All done? */
457 if (!num_create)
458 goto cleanup;
461 * This basically does a test for the rename matrix not
462 * growing larger than a "rename_limit" square matrix, ie:
464 * num_create * num_src > rename_limit * rename_limit
466 * but handles the potential overflow case specially (and we
467 * assume at least 32-bit integers)
469 if (rename_limit <= 0 || rename_limit > 32767)
470 rename_limit = 32767;
471 if (num_create > rename_limit && num_src > rename_limit)
472 goto cleanup;
473 if (num_create * num_src > rename_limit * rename_limit)
474 goto cleanup;
476 mx = xmalloc(sizeof(*mx) * num_create * num_src);
477 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
478 int base = dst_cnt * num_src;
479 struct diff_filespec *two = rename_dst[i].two;
480 if (rename_dst[i].pair)
481 continue; /* dealt with exact match already. */
482 for (j = 0; j < rename_src_nr; j++) {
483 struct diff_filespec *one = rename_src[j].one;
484 struct diff_score *m = &mx[base+j];
485 m->src = j;
486 m->dst = i;
487 m->score = estimate_similarity(one, two,
488 minimum_score);
489 m->name_score = basename_same(one, two);
490 diff_free_filespec_blob(one);
492 /* We do not need the text anymore */
493 diff_free_filespec_blob(two);
494 dst_cnt++;
496 /* cost matrix sorted by most to least similar pair */
497 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
498 for (i = 0; i < num_create * num_src; i++) {
499 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
500 struct diff_filespec *src;
501 if (dst->pair)
502 continue; /* already done, either exact or fuzzy. */
503 if (mx[i].score < minimum_score)
504 break; /* there is no more usable pair. */
505 src = rename_src[mx[i].src].one;
506 if (src->rename_used)
507 continue;
508 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
509 rename_count++;
511 for (i = 0; i < num_create * num_src; i++) {
512 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
513 if (dst->pair)
514 continue; /* already done, either exact or fuzzy. */
515 if (mx[i].score < minimum_score)
516 break; /* there is no more usable pair. */
517 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
518 rename_count++;
520 free(mx);
522 cleanup:
523 /* At this point, we have found some renames and copies and they
524 * are recorded in rename_dst. The original list is still in *q.
526 outq.queue = NULL;
527 outq.nr = outq.alloc = 0;
528 for (i = 0; i < q->nr; i++) {
529 struct diff_filepair *p = q->queue[i];
530 struct diff_filepair *pair_to_free = NULL;
532 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
534 * Creation
536 * We would output this create record if it has
537 * not been turned into a rename/copy already.
539 struct diff_rename_dst *dst =
540 locate_rename_dst(p->two, 0);
541 if (dst && dst->pair) {
542 diff_q(&outq, dst->pair);
543 pair_to_free = p;
545 else
546 /* no matching rename/copy source, so
547 * record this as a creation.
549 diff_q(&outq, p);
551 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
553 * Deletion
555 * We would output this delete record if:
557 * (1) this is a broken delete and the counterpart
558 * broken create remains in the output; or
559 * (2) this is not a broken delete, and rename_dst
560 * does not have a rename/copy to move p->one->path
561 * out of existence.
563 * Otherwise, the counterpart broken create
564 * has been turned into a rename-edit; or
565 * delete did not have a matching create to
566 * begin with.
568 if (DIFF_PAIR_BROKEN(p)) {
569 /* broken delete */
570 struct diff_rename_dst *dst =
571 locate_rename_dst(p->one, 0);
572 if (dst && dst->pair)
573 /* counterpart is now rename/copy */
574 pair_to_free = p;
576 else {
577 if (p->one->rename_used)
578 /* this path remains */
579 pair_to_free = p;
582 if (pair_to_free)
584 else
585 diff_q(&outq, p);
587 else if (!diff_unmodified_pair(p))
588 /* all the usual ones need to be kept */
589 diff_q(&outq, p);
590 else
591 /* no need to keep unmodified pairs */
592 pair_to_free = p;
594 if (pair_to_free)
595 diff_free_filepair(pair_to_free);
597 diff_debug_queue("done copying original", &outq);
599 free(q->queue);
600 *q = outq;
601 diff_debug_queue("done collapsing", q);
603 for (i = 0; i < rename_dst_nr; i++)
604 free_filespec(rename_dst[i].two);
606 free(rename_dst);
607 rename_dst = NULL;
608 rename_dst_nr = rename_dst_alloc = 0;
609 free(rename_src);
610 rename_src = NULL;
611 rename_src_nr = rename_src_alloc = 0;
612 return;