buitin/describe.c: use new hash map implementation
[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"
3ac942d4 8#include "progress.h"
427dcb4b 9
25d5ea41
JH
10/* Table of rename/copy destinations */
11
12static struct diff_rename_dst {
13 struct diff_filespec *two;
14 struct diff_filepair *pair;
15} *rename_dst;
16static int rename_dst_nr, rename_dst_alloc;
427dcb4b 17
25d5ea41
JH
18static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
19 int insert_ok)
427dcb4b 20{
25d5ea41
JH
21 int first, last;
22
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 dst;
31 if (cmp < 0) {
32 last = next;
33 continue;
34 }
35 first = next+1;
36 }
37 /* not found */
38 if (!insert_ok)
39 return NULL;
40 /* insert to make it at "first" */
41 if (rename_dst_alloc <= rename_dst_nr) {
42 rename_dst_alloc = alloc_nr(rename_dst_alloc);
43 rename_dst = xrealloc(rename_dst,
44 rename_dst_alloc * sizeof(*rename_dst));
45 }
46 rename_dst_nr++;
47 if (first < rename_dst_nr)
48 memmove(rename_dst + first + 1, rename_dst + first,
49 (rename_dst_nr - first - 1) * sizeof(*rename_dst));
5098bafb 50 rename_dst[first].two = alloc_filespec(two->path);
e5450100 51 fill_filespec(rename_dst[first].two, two->sha1, two->sha1_valid, two->mode);
25d5ea41
JH
52 rename_dst[first].pair = NULL;
53 return &(rename_dst[first]);
427dcb4b
JH
54}
55
15d061b4 56/* Table of rename/copy src files */
25d5ea41 57static struct diff_rename_src {
e88d6bc6 58 struct diff_filepair *p;
fc580719 59 unsigned short score; /* to remember the break score */
25d5ea41
JH
60} *rename_src;
61static int rename_src_nr, rename_src_alloc;
427dcb4b 62
e88d6bc6 63static struct diff_rename_src *register_rename_src(struct diff_filepair *p)
25d5ea41
JH
64{
65 int first, last;
e88d6bc6
JH
66 struct diff_filespec *one = p->one;
67 unsigned short score = p->score;
25d5ea41
JH
68
69 first = 0;
70 last = rename_src_nr;
71 while (last > first) {
72 int next = (last + first) >> 1;
73 struct diff_rename_src *src = &(rename_src[next]);
e88d6bc6 74 int cmp = strcmp(one->path, src->p->one->path);
25d5ea41
JH
75 if (!cmp)
76 return src;
77 if (cmp < 0) {
78 last = next;
79 continue;
80 }
81 first = next+1;
82 }
15d061b4 83
25d5ea41
JH
84 /* insert to make it at "first" */
85 if (rename_src_alloc <= rename_src_nr) {
86 rename_src_alloc = alloc_nr(rename_src_alloc);
87 rename_src = xrealloc(rename_src,
88 rename_src_alloc * sizeof(*rename_src));
427dcb4b 89 }
25d5ea41
JH
90 rename_src_nr++;
91 if (first < rename_src_nr)
92 memmove(rename_src + first + 1, rename_src + first,
93 (rename_src_nr - first - 1) * sizeof(*rename_src));
e88d6bc6 94 rename_src[first].p = p;
fc580719 95 rename_src[first].score = score;
25d5ea41 96 return &(rename_src[first]);
427dcb4b
JH
97}
98
0ce39643
JS
99static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
100{
101 int src_len = strlen(src->path), dst_len = strlen(dst->path);
102 while (src_len && dst_len) {
103 char c1 = src->path[--src_len];
104 char c2 = dst->path[--dst_len];
105 if (c1 != c2)
106 return 0;
107 if (c1 == '/')
108 return 1;
109 }
110 return (!src_len || src->path[src_len - 1] == '/') &&
111 (!dst_len || dst->path[dst_len - 1] == '/');
112}
113
427dcb4b 114struct diff_score {
25d5ea41
JH
115 int src; /* index in rename_src */
116 int dst; /* index in rename_dst */
6d24ad97
JH
117 unsigned short score;
118 short name_score;
427dcb4b
JH
119};
120
121static int estimate_similarity(struct diff_filespec *src,
122 struct diff_filespec *dst,
123 int minimum_score)
124{
125 /* src points at a file that existed in the original tree (or
126 * optionally a file in the destination tree) and dst points
127 * at a newly created file. They may be quite similar, in which
128 * case we want to say src is renamed to dst or src is copied into
129 * dst, and then some edit has been applied to dst.
130 *
131 * Compare them and return how similar they are, representing
f0c6b2a2
JH
132 * the score as an integer between 0 and MAX_SCORE.
133 *
134 * When there is an exact match, it is considered a better
135 * match than anything else; the destination does not even
136 * call into this function in that case.
427dcb4b 137 */
90bd932c 138 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
75c660ac 139 unsigned long delta_limit;
427dcb4b
JH
140 int score;
141
60896c7b
JH
142 /* We deal only with regular files. Symlink renames are handled
143 * only when they are exact matches --- in other words, no edits
144 * after renaming.
145 */
146 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
147 return 0;
148
81ac051d
LT
149 /*
150 * Need to check that source and destination sizes are
151 * filled in before comparing them.
152 *
153 * If we already have "cnt_data" filled in, we know it's
154 * all good (avoid checking the size for zero, as that
155 * is a possible size - we really should have a flag to
156 * say whether the size is valid or not!)
157 */
885c716f 158 if (!src->cnt_data && diff_populate_filespec(src, 1))
81ac051d 159 return 0;
885c716f 160 if (!dst->cnt_data && diff_populate_filespec(dst, 1))
81ac051d
LT
161 return 0;
162
90bd932c 163 max_size = ((src->size > dst->size) ? src->size : dst->size);
58b103f5 164 base_size = ((src->size < dst->size) ? src->size : dst->size);
90bd932c 165 delta_size = max_size - base_size;
427dcb4b 166
58b103f5
JH
167 /* We would not consider edits that change the file size so
168 * drastically. delta_size must be smaller than
cd1870ed 169 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
f0c6b2a2 170 *
58b103f5
JH
171 * Note that base_size == 0 case is handled here already
172 * and the final score computation below would not have a
173 * divide-by-zero issue.
427dcb4b 174 */
3a4d6769 175 if (max_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
427dcb4b
JH
176 return 0;
177
885c716f
BS
178 if (!src->cnt_data && diff_populate_filespec(src, 0))
179 return 0;
180 if (!dst->cnt_data && diff_populate_filespec(dst, 0))
181 return 0;
182
dc49cd76
SP
183 delta_limit = (unsigned long)
184 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
d8c3d03a 185 if (diffcore_count_changes(src, dst,
c06c7966 186 &src->cnt_data, &dst->cnt_data,
65416758
JH
187 delta_limit,
188 &src_copied, &literal_added))
85976974 189 return 0;
355e76a4 190
1706306a
JH
191 /* How similar are they?
192 * what percentage of material in dst are from source?
427dcb4b 193 */
90bd932c 194 if (!dst->size)
1706306a 195 score = 0; /* should not happen */
cfc0aef1 196 else
dc49cd76 197 score = (int)(src_copied * MAX_SCORE / max_size);
427dcb4b
JH
198 return score;
199}
200
5098bafb 201static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 202{
9fb88419 203 struct diff_filespec *src, *dst;
25d5ea41 204 struct diff_filepair *dp;
f7c1512a 205
25d5ea41
JH
206 if (rename_dst[dst_index].pair)
207 die("internal error: dst already matched.");
427dcb4b 208
e88d6bc6 209 src = rename_src[src_index].p->one;
64479711 210 src->rename_used++;
9fb88419 211 src->count++;
427dcb4b 212
25d5ea41 213 dst = rename_dst[dst_index].two;
9fb88419 214 dst->count++;
427dcb4b 215
9fb88419 216 dp = diff_queue(NULL, src, dst);
ef677686 217 dp->renamed_pair = 1;
fc580719
JH
218 if (!strcmp(src->path, dst->path))
219 dp->score = rename_src[src_index].score;
220 else
221 dp->score = score;
25d5ea41 222 rename_dst[dst_index].pair = dp;
427dcb4b
JH
223}
224
225/*
226 * We sort the rename similarity matrix with the score, in descending
15d061b4 227 * order (the most similar first).
427dcb4b
JH
228 */
229static int score_compare(const void *a_, const void *b_)
230{
231 const struct diff_score *a = a_, *b = b_;
cfc0aef1 232
6d24ad97
JH
233 /* sink the unused ones to the bottom */
234 if (a->dst < 0)
235 return (0 <= b->dst);
236 else if (b->dst < 0)
237 return -1;
238
cfc0aef1
RS
239 if (a->score == b->score)
240 return b->name_score - a->name_score;
241
427dcb4b
JH
242 return b->score - a->score;
243}
244
9027f53c
LT
245struct file_similarity {
246 int src_dst, index;
247 struct diff_filespec *filespec;
248 struct file_similarity *next;
249};
250
251static int find_identical_files(struct file_similarity *src,
11f944dd
LT
252 struct file_similarity *dst,
253 struct diff_options *options)
9027f53c
LT
254{
255 int renames = 0;
256
257 /*
258 * Walk over all the destinations ...
259 */
260 do {
32d75d29 261 struct diff_filespec *target = dst->filespec;
9027f53c 262 struct file_similarity *p, *best;
32d75d29 263 int i = 100, best_score = -1;
9027f53c
LT
264
265 /*
266 * .. to find the best source match
267 */
268 best = NULL;
269 for (p = src; p; p = p->next) {
32d75d29
LT
270 int score;
271 struct diff_filespec *source = p->filespec;
9027f53c 272
3ea3c215 273 /* False hash collision? */
32d75d29 274 if (hashcmp(source->sha1, target->sha1))
9027f53c
LT
275 continue;
276 /* Non-regular files? If so, the modes must match! */
32d75d29
LT
277 if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) {
278 if (source->mode != target->mode)
9027f53c
LT
279 continue;
280 }
32d75d29
LT
281 /* Give higher scores to sources that haven't been used already */
282 score = !source->rename_used;
0940e5f2
LT
283 if (source->rename_used && options->detect_rename != DIFF_DETECT_COPY)
284 continue;
32d75d29
LT
285 score += basename_same(source, target);
286 if (score > best_score) {
287 best = p;
288 best_score = score;
289 if (score == 2)
290 break;
291 }
9027f53c
LT
292
293 /* Too many identical alternatives? Pick one */
294 if (!--i)
295 break;
296 }
297 if (best) {
298 record_rename_pair(dst->index, best->index, MAX_SCORE);
299 renames++;
300 }
301 } while ((dst = dst->next) != NULL);
302 return renames;
303}
304
9027f53c
LT
305static void free_similarity_list(struct file_similarity *p)
306{
307 while (p) {
308 struct file_similarity *entry = p;
309 p = p->next;
9027f53c
LT
310 free(entry);
311 }
312}
313
11f944dd 314static int find_same_files(void *ptr, void *data)
9027f53c
LT
315{
316 int ret;
317 struct file_similarity *p = ptr;
318 struct file_similarity *src = NULL, *dst = NULL;
11f944dd 319 struct diff_options *options = data;
9027f53c
LT
320
321 /* Split the hash list up into sources and destinations */
322 do {
323 struct file_similarity *entry = p;
324 p = p->next;
325 if (entry->src_dst < 0) {
326 entry->next = src;
327 src = entry;
328 } else {
329 entry->next = dst;
330 dst = entry;
331 }
332 } while (p);
333
334 /*
335 * If we have both sources *and* destinations, see if
336 * we can match them up
337 */
11f944dd 338 ret = (src && dst) ? find_identical_files(src, dst, options) : 0;
9027f53c
LT
339
340 /* Free the hashes and return the number of renames found */
341 free_similarity_list(src);
342 free_similarity_list(dst);
343 return ret;
344}
345
346static unsigned int hash_filespec(struct diff_filespec *filespec)
347{
348 unsigned int hash;
349 if (!filespec->sha1_valid) {
350 if (diff_populate_filespec(filespec, 0))
351 return 0;
352 hash_sha1_file(filespec->data, filespec->size, "blob", filespec->sha1);
353 }
354 memcpy(&hash, filespec->sha1, sizeof(hash));
355 return hash;
356}
357
358static void insert_file_table(struct hash_table *table, int src_dst, int index, struct diff_filespec *filespec)
359{
360 void **pos;
361 unsigned int hash;
362 struct file_similarity *entry = xmalloc(sizeof(*entry));
363
364 entry->src_dst = src_dst;
365 entry->index = index;
366 entry->filespec = filespec;
367 entry->next = NULL;
368
369 hash = hash_filespec(filespec);
370 pos = insert_hash(hash, entry, table);
371
372 /* We already had an entry there? */
373 if (pos) {
374 entry->next = *pos;
375 *pos = entry;
376 }
377}
378
cb1491b6
LT
379/*
380 * Find exact renames first.
381 *
382 * The first round matches up the up-to-date entries,
383 * and then during the second round we try to match
384 * cache-dirty entries as well.
cb1491b6 385 */
11f944dd 386static int find_exact_renames(struct diff_options *options)
cb1491b6 387{
9027f53c
LT
388 int i;
389 struct hash_table file_table;
cb1491b6 390
9027f53c 391 init_hash(&file_table);
c7359281 392 preallocate_hash(&file_table, rename_src_nr + rename_dst_nr);
9027f53c 393 for (i = 0; i < rename_src_nr; i++)
e88d6bc6 394 insert_file_table(&file_table, -1, i, rename_src[i].p->one);
9027f53c
LT
395
396 for (i = 0; i < rename_dst_nr; i++)
397 insert_file_table(&file_table, 1, i, rename_dst[i].two);
398
399 /* Find the renames */
11f944dd 400 i = for_each_hash(&file_table, find_same_files, options);
9027f53c
LT
401
402 /* .. and free the hash data structure */
403 free_hash(&file_table);
404
405 return i;
cb1491b6
LT
406}
407
6d24ad97
JH
408#define NUM_CANDIDATE_PER_DST 4
409static void record_if_better(struct diff_score m[], struct diff_score *o)
410{
411 int i, worst;
412
413 /* find the worst one */
414 worst = 0;
415 for (i = 1; i < NUM_CANDIDATE_PER_DST; i++)
416 if (score_compare(&m[i], &m[worst]) > 0)
417 worst = i;
418
419 /* is it better than the worst one? */
420 if (score_compare(&m[worst], o) > 0)
421 m[worst] = *o;
422}
423
f31027c9
JH
424/*
425 * Returns:
426 * 0 if we are under the limit;
427 * 1 if we need to disable inexact rename detection;
428 * 2 if we would be under the limit if we were given -C instead of -C -C.
429 */
9d8a5a50
JH
430static int too_many_rename_candidates(int num_create,
431 struct diff_options *options)
432{
433 int rename_limit = options->rename_limit;
434 int num_src = rename_src_nr;
f31027c9 435 int i;
9d8a5a50
JH
436
437 options->needed_rename_limit = 0;
438
439 /*
440 * This basically does a test for the rename matrix not
441 * growing larger than a "rename_limit" square matrix, ie:
442 *
443 * num_create * num_src > rename_limit * rename_limit
444 *
445 * but handles the potential overflow case specially (and we
446 * assume at least 32-bit integers)
447 */
448 if (rename_limit <= 0 || rename_limit > 32767)
449 rename_limit = 32767;
450 if ((num_create <= rename_limit || num_src <= rename_limit) &&
451 (num_create * num_src <= rename_limit * rename_limit))
452 return 0;
453
454 options->needed_rename_limit =
455 num_src > num_create ? num_src : num_create;
f31027c9
JH
456
457 /* Are we running under -C -C? */
458 if (!DIFF_OPT_TST(options, FIND_COPIES_HARDER))
459 return 1;
460
461 /* Would we bust the limit if we were running under -C? */
462 for (num_src = i = 0; i < rename_src_nr; i++) {
463 if (diff_unmodified_pair(rename_src[i].p))
464 continue;
465 num_src++;
466 }
467 if ((num_create <= rename_limit || num_src <= rename_limit) &&
468 (num_create * num_src <= rename_limit * rename_limit))
469 return 2;
9d8a5a50
JH
470 return 1;
471}
472
0940e5f2
LT
473static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, int copies)
474{
475 int count = 0, i;
476
477 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
478 struct diff_rename_dst *dst;
479
480 if ((mx[i].dst < 0) ||
481 (mx[i].score < minimum_score))
482 break; /* there is no more usable pair. */
483 dst = &rename_dst[mx[i].dst];
484 if (dst->pair)
485 continue; /* already done, either exact or fuzzy. */
e88d6bc6 486 if (!copies && rename_src[mx[i].src].p->one->rename_used)
0940e5f2
LT
487 continue;
488 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
489 count++;
490 }
491 return count;
492}
493
8082d8d3 494void diffcore_rename(struct diff_options *options)
427dcb4b 495{
8082d8d3
JH
496 int detect_rename = options->detect_rename;
497 int minimum_score = options->rename_score;
38c6f780 498 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 499 struct diff_queue_struct outq;
427dcb4b 500 struct diff_score *mx;
f31027c9 501 int i, j, rename_count, skip_unmodified = 0;
dabdbee1 502 int num_create, dst_cnt;
3ac942d4 503 struct progress *progress = NULL;
427dcb4b 504
26dee0ad 505 if (!minimum_score)
f345b0a0 506 minimum_score = DEFAULT_RENAME_SCORE;
427dcb4b 507
427dcb4b 508 for (i = 0; i < q->nr; i++) {
52e95789 509 struct diff_filepair *p = q->queue[i];
2f3f8b21 510 if (!DIFF_FILE_VALID(p->one)) {
81e50eab 511 if (!DIFF_FILE_VALID(p->two))
60896c7b 512 continue; /* unmerged */
2f3f8b21
JH
513 else if (options->single_follow &&
514 strcmp(options->single_follow, p->two->path))
515 continue; /* not interested */
90d43b07
JK
516 else if (!DIFF_OPT_TST(options, RENAME_EMPTY) &&
517 is_empty_blob_sha1(p->two->sha1))
518 continue;
427dcb4b 519 else
25d5ea41 520 locate_rename_dst(p->two, 1);
2f3f8b21 521 }
90d43b07
JK
522 else if (!DIFF_OPT_TST(options, RENAME_EMPTY) &&
523 is_empty_blob_sha1(p->one->sha1))
524 continue;
d7c9bf22 525 else if (!DIFF_PAIR_UNMERGED(p) && !DIFF_FILE_VALID(p->two)) {
64479711
LT
526 /*
527 * If the source is a broken "delete", and
2210100a
JH
528 * they did not really want to get broken,
529 * that means the source actually stays.
64479711
LT
530 * So we increment the "rename_used" score
531 * by one, to indicate ourselves as a user
532 */
533 if (p->broken_pair && !p->score)
534 p->one->rename_used++;
e88d6bc6 535 register_rename_src(p);
64479711
LT
536 }
537 else if (detect_rename == DIFF_DETECT_COPY) {
538 /*
539 * Increment the "rename_used" score by
540 * one, to indicate ourselves as a user.
2210100a 541 */
64479711 542 p->one->rename_used++;
e88d6bc6 543 register_rename_src(p);
2210100a 544 }
427dcb4b 545 }
0024a549 546 if (rename_dst_nr == 0 || rename_src_nr == 0)
427dcb4b
JH
547 goto cleanup; /* nothing to do */
548
17559a64
LT
549 /*
550 * We really want to cull the candidates list early
551 * with cheap tests in order to avoid doing deltas.
552 */
11f944dd 553 rename_count = find_exact_renames(options);
17559a64 554
42899ac8
LT
555 /* Did we only want exact renames? */
556 if (minimum_score == MAX_SCORE)
557 goto cleanup;
558
559 /*
560 * Calculate how many renames are left (but all the source
561 * files still remain as options for rename/copies!)
562 */
563 num_create = (rename_dst_nr - rename_count);
42899ac8
LT
564
565 /* All done? */
566 if (!num_create)
567 goto cleanup;
568
f31027c9
JH
569 switch (too_many_rename_candidates(num_create, options)) {
570 case 1:
0024a549 571 goto cleanup;
f31027c9
JH
572 case 2:
573 options->degraded_cc_to_c = 1;
574 skip_unmodified = 1;
575 break;
576 default:
577 break;
578 }
0024a549 579
3ac942d4
JK
580 if (options->show_rename_progress) {
581 progress = start_progress_delay(
582 "Performing inexact rename detection",
583 rename_dst_nr * rename_src_nr, 50, 1);
584 }
585
6d24ad97 586 mx = xcalloc(num_create * NUM_CANDIDATE_PER_DST, sizeof(*mx));
25d5ea41 587 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
25d5ea41 588 struct diff_filespec *two = rename_dst[i].two;
6d24ad97
JH
589 struct diff_score *m;
590
25d5ea41 591 if (rename_dst[i].pair)
427dcb4b 592 continue; /* dealt with exact match already. */
6d24ad97
JH
593
594 m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST];
595 for (j = 0; j < NUM_CANDIDATE_PER_DST; j++)
596 m[j].dst = -1;
597
25d5ea41 598 for (j = 0; j < rename_src_nr; j++) {
e88d6bc6 599 struct diff_filespec *one = rename_src[j].p->one;
6d24ad97 600 struct diff_score this_src;
f31027c9
JH
601
602 if (skip_unmodified &&
603 diff_unmodified_pair(rename_src[j].p))
604 continue;
605
6d24ad97
JH
606 this_src.score = estimate_similarity(one, two,
607 minimum_score);
608 this_src.name_score = basename_same(one, two);
609 this_src.dst = i;
610 this_src.src = j;
611 record_if_better(m, &this_src);
809809bb
JH
612 /*
613 * Once we run estimate_similarity,
614 * We do not need the text anymore.
615 */
8ae92e63 616 diff_free_filespec_blob(one);
809809bb 617 diff_free_filespec_blob(two);
427dcb4b
JH
618 }
619 dst_cnt++;
3ac942d4 620 display_progress(progress, (i+1)*rename_src_nr);
427dcb4b 621 }
3ac942d4 622 stop_progress(&progress);
6d24ad97 623
427dcb4b 624 /* cost matrix sorted by most to least similar pair */
6d24ad97
JH
625 qsort(mx, dst_cnt * NUM_CANDIDATE_PER_DST, sizeof(*mx), score_compare);
626
0940e5f2
LT
627 rename_count += find_renames(mx, dst_cnt, minimum_score, 0);
628 if (detect_rename == DIFF_DETECT_COPY)
629 rename_count += find_renames(mx, dst_cnt, minimum_score, 1);
427dcb4b 630 free(mx);
427dcb4b 631
15d061b4 632 cleanup:
427dcb4b 633 /* At this point, we have found some renames and copies and they
5098bafb 634 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 635 */
9ca5df90 636 DIFF_QUEUE_CLEAR(&outq);
427dcb4b 637 for (i = 0; i < q->nr; i++) {
25d5ea41 638 struct diff_filepair *p = q->queue[i];
25d5ea41
JH
639 struct diff_filepair *pair_to_free = NULL;
640
d7c9bf22
MZ
641 if (DIFF_PAIR_UNMERGED(p)) {
642 diff_q(&outq, p);
643 }
644 else if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2cd68882
JH
645 /*
646 * Creation
647 *
648 * We would output this create record if it has
649 * not been turned into a rename/copy already.
650 */
651 struct diff_rename_dst *dst =
652 locate_rename_dst(p->two, 0);
653 if (dst && dst->pair) {
25d5ea41
JH
654 diff_q(&outq, dst->pair);
655 pair_to_free = p;
656 }
657 else
2cd68882
JH
658 /* no matching rename/copy source, so
659 * record this as a creation.
25d5ea41
JH
660 */
661 diff_q(&outq, p);
427dcb4b 662 }
2cd68882
JH
663 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
664 /*
665 * Deletion
666 *
f345b0a0
JH
667 * We would output this delete record if:
668 *
669 * (1) this is a broken delete and the counterpart
670 * broken create remains in the output; or
5098bafb
JH
671 * (2) this is not a broken delete, and rename_dst
672 * does not have a rename/copy to move p->one->path
673 * out of existence.
f345b0a0
JH
674 *
675 * Otherwise, the counterpart broken create
676 * has been turned into a rename-edit; or
677 * delete did not have a matching create to
678 * begin with.
2cd68882 679 */
f345b0a0
JH
680 if (DIFF_PAIR_BROKEN(p)) {
681 /* broken delete */
682 struct diff_rename_dst *dst =
683 locate_rename_dst(p->one, 0);
684 if (dst && dst->pair)
685 /* counterpart is now rename/copy */
686 pair_to_free = p;
687 }
688 else {
64479711 689 if (p->one->rename_used)
f345b0a0
JH
690 /* this path remains */
691 pair_to_free = p;
692 }
2cd68882
JH
693
694 if (pair_to_free)
695 ;
696 else
697 diff_q(&outq, p);
698 }
25d5ea41 699 else if (!diff_unmodified_pair(p))
15d061b4 700 /* all the usual ones need to be kept */
25d5ea41 701 diff_q(&outq, p);
15d061b4
JH
702 else
703 /* no need to keep unmodified pairs */
704 pair_to_free = p;
705
226406f6
JH
706 if (pair_to_free)
707 diff_free_filepair(pair_to_free);
427dcb4b 708 }
25d5ea41 709 diff_debug_queue("done copying original", &outq);
427dcb4b 710
25d5ea41
JH
711 free(q->queue);
712 *q = outq;
713 diff_debug_queue("done collapsing", q);
427dcb4b 714
9fb88419
LT
715 for (i = 0; i < rename_dst_nr; i++)
716 free_filespec(rename_dst[i].two);
5098bafb 717
25d5ea41
JH
718 free(rename_dst);
719 rename_dst = NULL;
720 rename_dst_nr = rename_dst_alloc = 0;
721 free(rename_src);
722 rename_src = NULL;
723 rename_src_nr = rename_src_alloc = 0;
427dcb4b
JH
724 return;
725}