Mention 'cpio' dependency in INSTALL
[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);
25d5ea41
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50 rename_dst[first].pair = NULL;
51 return &(rename_dst[first]);
427dcb4b
JH
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
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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
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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
f0c6b2a2
JH
187 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
188 return 0; /* error but caught downstream */
189
85976974 190
dc49cd76
SP
191 delta_limit = (unsigned long)
192 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
d8c3d03a 193 if (diffcore_count_changes(src, dst,
c06c7966 194 &src->cnt_data, &dst->cnt_data,
65416758
JH
195 delta_limit,
196 &src_copied, &literal_added))
85976974 197 return 0;
355e76a4 198
1706306a
JH
199 /* How similar are they?
200 * what percentage of material in dst are from source?
427dcb4b 201 */
90bd932c 202 if (!dst->size)
1706306a 203 score = 0; /* should not happen */
cfc0aef1 204 else
dc49cd76 205 score = (int)(src_copied * MAX_SCORE / max_size);
427dcb4b
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206 return score;
207}
208
5098bafb 209static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 210{
25d5ea41
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211 struct diff_filespec *one, *two, *src, *dst;
212 struct diff_filepair *dp;
f7c1512a 213
25d5ea41
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214 if (rename_dst[dst_index].pair)
215 die("internal error: dst already matched.");
427dcb4b 216
25d5ea41
JH
217 src = rename_src[src_index].one;
218 one = alloc_filespec(src->path);
219 fill_filespec(one, src->sha1, src->mode);
427dcb4b 220
25d5ea41
JH
221 dst = rename_dst[dst_index].two;
222 two = alloc_filespec(dst->path);
223 fill_filespec(two, dst->sha1, dst->mode);
427dcb4b 224
5098bafb 225 dp = diff_queue(NULL, one, two);
ef677686 226 dp->renamed_pair = 1;
fc580719
JH
227 if (!strcmp(src->path, dst->path))
228 dp->score = rename_src[src_index].score;
229 else
230 dp->score = score;
6bac10d8 231 dp->source_stays = rename_src[src_index].src_path_left;
25d5ea41 232 rename_dst[dst_index].pair = dp;
427dcb4b
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233}
234
235/*
236 * We sort the rename similarity matrix with the score, in descending
15d061b4 237 * order (the most similar first).
427dcb4b
JH
238 */
239static int score_compare(const void *a_, const void *b_)
240{
241 const struct diff_score *a = a_, *b = b_;
cfc0aef1
RS
242
243 if (a->score == b->score)
244 return b->name_score - a->name_score;
245
427dcb4b
JH
246 return b->score - a->score;
247}
248
6bac10d8
JH
249static int compute_stays(struct diff_queue_struct *q,
250 struct diff_filespec *one)
251{
252 int i;
253 for (i = 0; i < q->nr; i++) {
254 struct diff_filepair *p = q->queue[i];
255 if (strcmp(one->path, p->two->path))
256 continue;
257 if (DIFF_PAIR_RENAME(p)) {
258 return 0; /* something else is renamed into this */
259 }
260 }
261 return 1;
262}
263
8082d8d3 264void diffcore_rename(struct diff_options *options)
427dcb4b 265{
8082d8d3
JH
266 int detect_rename = options->detect_rename;
267 int minimum_score = options->rename_score;
268 int rename_limit = options->rename_limit;
38c6f780 269 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 270 struct diff_queue_struct outq;
427dcb4b 271 struct diff_score *mx;
17e6019a 272 int i, j, rename_count, contents_too;
25d5ea41 273 int num_create, num_src, dst_cnt;
427dcb4b 274
26dee0ad 275 if (!minimum_score)
f345b0a0 276 minimum_score = DEFAULT_RENAME_SCORE;
5098bafb 277 rename_count = 0;
427dcb4b 278
427dcb4b 279 for (i = 0; i < q->nr; i++) {
52e95789 280 struct diff_filepair *p = q->queue[i];
2f3f8b21 281 if (!DIFF_FILE_VALID(p->one)) {
81e50eab 282 if (!DIFF_FILE_VALID(p->two))
60896c7b 283 continue; /* unmerged */
2f3f8b21
JH
284 else if (options->single_follow &&
285 strcmp(options->single_follow, p->two->path))
286 continue; /* not interested */
427dcb4b 287 else
25d5ea41 288 locate_rename_dst(p->two, 1);
2f3f8b21 289 }
2210100a
JH
290 else if (!DIFF_FILE_VALID(p->two)) {
291 /* If the source is a broken "delete", and
292 * they did not really want to get broken,
293 * that means the source actually stays.
294 */
295 int stays = (p->broken_pair && !p->score);
fc580719 296 register_rename_src(p->one, stays, p->score);
2210100a 297 }
15d061b4 298 else if (detect_rename == DIFF_DETECT_COPY)
fc580719 299 register_rename_src(p->one, 1, p->score);
427dcb4b 300 }
0024a549 301 if (rename_dst_nr == 0 || rename_src_nr == 0)
427dcb4b
JH
302 goto cleanup; /* nothing to do */
303
0024a549
LT
304 /*
305 * This basically does a test for the rename matrix not
306 * growing larger than a "rename_limit" square matrix, ie:
307 *
308 * rename_dst_nr * rename_src_nr > rename_limit * rename_limit
309 *
310 * but handles the potential overflow case specially (and we
311 * assume at least 32-bit integers)
312 */
313 if (rename_limit <= 0 || rename_limit > 32767)
314 rename_limit = 32767;
315 if (rename_dst_nr > rename_limit && rename_src_nr > rename_limit)
316 goto cleanup;
317 if (rename_dst_nr * rename_src_nr > rename_limit * rename_limit)
318 goto cleanup;
319
427dcb4b
JH
320 /* We really want to cull the candidates list early
321 * with cheap tests in order to avoid doing deltas.
17e6019a
JH
322 * The first round matches up the up-to-date entries,
323 * and then during the second round we try to match
324 * cache-dirty entries as well.
427dcb4b 325 */
17e6019a
JH
326 for (contents_too = 0; contents_too < 2; contents_too++) {
327 for (i = 0; i < rename_dst_nr; i++) {
328 struct diff_filespec *two = rename_dst[i].two;
329 if (rename_dst[i].pair)
330 continue; /* dealt with an earlier round */
331 for (j = 0; j < rename_src_nr; j++) {
0ce39643 332 int k;
17e6019a
JH
333 struct diff_filespec *one = rename_src[j].one;
334 if (!is_exact_match(one, two, contents_too))
335 continue;
0ce39643
JS
336
337 /* see if there is a basename match, too */
338 for (k = j; k < rename_src_nr; k++) {
339 one = rename_src[k].one;
340 if (basename_same(one, two) &&
341 is_exact_match(one, two,
342 contents_too)) {
343 j = k;
344 break;
345 }
346 }
347
dc49cd76 348 record_rename_pair(i, j, (int)MAX_SCORE);
17e6019a
JH
349 rename_count++;
350 break; /* we are done with this entry */
351 }
427dcb4b
JH
352 }
353 }
427dcb4b
JH
354
355 /* Have we run out the created file pool? If so we can avoid
356 * doing the delta matrix altogether.
357 */
5098bafb 358 if (rename_count == rename_dst_nr)
15d061b4 359 goto cleanup;
427dcb4b 360
9f70b806
JH
361 if (minimum_score == MAX_SCORE)
362 goto cleanup;
363
5098bafb 364 num_create = (rename_dst_nr - rename_count);
25d5ea41 365 num_src = rename_src_nr;
427dcb4b 366 mx = xmalloc(sizeof(*mx) * num_create * num_src);
25d5ea41 367 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
427dcb4b 368 int base = dst_cnt * num_src;
25d5ea41
JH
369 struct diff_filespec *two = rename_dst[i].two;
370 if (rename_dst[i].pair)
427dcb4b 371 continue; /* dealt with exact match already. */
25d5ea41
JH
372 for (j = 0; j < rename_src_nr; j++) {
373 struct diff_filespec *one = rename_src[j].one;
374 struct diff_score *m = &mx[base+j];
375 m->src = j;
376 m->dst = i;
377 m->score = estimate_similarity(one, two,
378 minimum_score);
cfc0aef1 379 m->name_score = basename_same(one, two);
50b2b538 380 diff_free_filespec_data(one);
427dcb4b 381 }
2821104d
JH
382 /* We do not need the text anymore */
383 diff_free_filespec_data(two);
427dcb4b
JH
384 dst_cnt++;
385 }
386 /* cost matrix sorted by most to least similar pair */
387 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
388 for (i = 0; i < num_create * num_src; i++) {
25d5ea41
JH
389 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
390 if (dst->pair)
391 continue; /* already done, either exact or fuzzy. */
427dcb4b 392 if (mx[i].score < minimum_score)
15d061b4 393 break; /* there is no more usable pair. */
5098bafb
JH
394 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
395 rename_count++;
427dcb4b
JH
396 }
397 free(mx);
427dcb4b 398
15d061b4 399 cleanup:
427dcb4b 400 /* At this point, we have found some renames and copies and they
5098bafb 401 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 402 */
25d5ea41
JH
403 outq.queue = NULL;
404 outq.nr = outq.alloc = 0;
427dcb4b 405 for (i = 0; i < q->nr; i++) {
25d5ea41 406 struct diff_filepair *p = q->queue[i];
25d5ea41
JH
407 struct diff_filepair *pair_to_free = NULL;
408
2cd68882
JH
409 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
410 /*
411 * Creation
412 *
413 * We would output this create record if it has
414 * not been turned into a rename/copy already.
415 */
416 struct diff_rename_dst *dst =
417 locate_rename_dst(p->two, 0);
418 if (dst && dst->pair) {
25d5ea41
JH
419 diff_q(&outq, dst->pair);
420 pair_to_free = p;
421 }
422 else
2cd68882
JH
423 /* no matching rename/copy source, so
424 * record this as a creation.
25d5ea41
JH
425 */
426 diff_q(&outq, p);
427dcb4b 427 }
2cd68882
JH
428 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
429 /*
430 * Deletion
431 *
f345b0a0
JH
432 * We would output this delete record if:
433 *
434 * (1) this is a broken delete and the counterpart
435 * broken create remains in the output; or
5098bafb
JH
436 * (2) this is not a broken delete, and rename_dst
437 * does not have a rename/copy to move p->one->path
438 * out of existence.
f345b0a0
JH
439 *
440 * Otherwise, the counterpart broken create
441 * has been turned into a rename-edit; or
442 * delete did not have a matching create to
443 * begin with.
2cd68882 444 */
f345b0a0
JH
445 if (DIFF_PAIR_BROKEN(p)) {
446 /* broken delete */
447 struct diff_rename_dst *dst =
448 locate_rename_dst(p->one, 0);
449 if (dst && dst->pair)
450 /* counterpart is now rename/copy */
451 pair_to_free = p;
452 }
453 else {
5098bafb
JH
454 for (j = 0; j < rename_dst_nr; j++) {
455 if (!rename_dst[j].pair)
456 continue;
457 if (strcmp(rename_dst[j].pair->
458 one->path,
459 p->one->path))
460 continue;
461 break;
462 }
463 if (j < rename_dst_nr)
f345b0a0
JH
464 /* this path remains */
465 pair_to_free = p;
466 }
2cd68882
JH
467
468 if (pair_to_free)
469 ;
470 else
471 diff_q(&outq, p);
472 }
25d5ea41 473 else if (!diff_unmodified_pair(p))
15d061b4 474 /* all the usual ones need to be kept */
25d5ea41 475 diff_q(&outq, p);
15d061b4
JH
476 else
477 /* no need to keep unmodified pairs */
478 pair_to_free = p;
479
226406f6
JH
480 if (pair_to_free)
481 diff_free_filepair(pair_to_free);
427dcb4b 482 }
25d5ea41 483 diff_debug_queue("done copying original", &outq);
427dcb4b 484
25d5ea41
JH
485 free(q->queue);
486 *q = outq;
487 diff_debug_queue("done collapsing", q);
427dcb4b 488
6bac10d8
JH
489 /* We need to see which rename source really stays here;
490 * earlier we only checked if the path is left in the result,
491 * but even if a path remains in the result, if that is coming
492 * from copying something else on top of it, then the original
493 * source is lost and does not stay.
494 */
495 for (i = 0; i < q->nr; i++) {
496 struct diff_filepair *p = q->queue[i];
497 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
498 /* If one appears as the target of a rename-copy,
499 * then mark p->source_stays = 0; otherwise
500 * leave it as is.
501 */
502 p->source_stays = compute_stays(q, p->one);
503 }
504 }
505
5098bafb
JH
506 for (i = 0; i < rename_dst_nr; i++) {
507 diff_free_filespec_data(rename_dst[i].two);
508 free(rename_dst[i].two);
509 }
510
25d5ea41
JH
511 free(rename_dst);
512 rename_dst = NULL;
513 rename_dst_nr = rename_dst_alloc = 0;
514 free(rename_src);
515 rename_src = NULL;
516 rename_src_nr = rename_src_alloc = 0;
427dcb4b
JH
517 return;
518}