packv4: nth_packed_object_sha1() packv4 support
[git/packv4.git] / diffcore-rename.c
blob6bde4396f212833cc1d411e723d5215c086e7c2d
1 /*
2 * Copyright (C) 2005 Junio C Hamano
3 */
4 #include "cache.h"
5 #include "diff.h"
6 #include "diffcore.h"
8 /* Table of rename/copy destinations */
10 static struct diff_rename_dst {
11 struct diff_filespec *two;
12 struct diff_filepair *pair;
13 } *rename_dst;
14 static int rename_dst_nr, rename_dst_alloc;
16 static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
17 int insert_ok)
19 int first, last;
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;
33 first = next+1;
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));
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));
48 rename_dst[first].two = alloc_filespec(two->path);
49 fill_filespec(rename_dst[first].two, two->sha1, two->mode);
50 rename_dst[first].pair = NULL;
51 return &(rename_dst[first]);
54 /* Table of rename/copy src files */
55 static struct diff_rename_src {
56 struct diff_filespec *one;
57 unsigned short score; /* to remember the break score */
58 unsigned src_path_left : 1;
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 int src_path_left,
64 unsigned short score)
66 int first, last;
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;
80 first = next+1;
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));
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;
94 rename_src[first].score = score;
95 rename_src[first].src_path_left = src_path_left;
96 return &(rename_src[first]);
99 static int is_exact_match(struct diff_filespec *src,
100 struct diff_filespec *dst,
101 int contents_too)
103 if (src->sha1_valid && dst->sha1_valid &&
104 !hashcmp(src->sha1, dst->sha1))
105 return 1;
106 if (!contents_too)
107 return 0;
108 if (diff_populate_filespec(src, 1) || diff_populate_filespec(dst, 1))
109 return 0;
110 if (src->size != dst->size)
111 return 0;
112 if (src->sha1_valid && dst->sha1_valid)
113 return !hashcmp(src->sha1, dst->sha1);
114 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
115 return 0;
116 if (src->size == dst->size &&
117 !memcmp(src->data, dst->data, src->size))
118 return 1;
119 return 0;
122 static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
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;
133 return (!src_len || src->path[src_len - 1] == '/') &&
134 (!dst_len || dst->path[dst_len - 1] == '/');
137 struct diff_score {
138 int src; /* index in rename_src */
139 int dst; /* index in rename_dst */
140 int score;
141 int name_score;
144 static int estimate_similarity(struct diff_filespec *src,
145 struct diff_filespec *dst,
146 int minimum_score)
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.
154 * Compare them and return how similar they are, representing
155 * the score as an integer between 0 and MAX_SCORE.
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.
161 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
162 unsigned long delta_limit;
163 int score;
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.
169 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
170 return 0;
172 max_size = ((src->size > dst->size) ? src->size : dst->size);
173 base_size = ((src->size < dst->size) ? src->size : dst->size);
174 delta_size = max_size - base_size;
176 /* We would not consider edits that change the file size so
177 * drastically. delta_size must be smaller than
178 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
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.
184 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
185 return 0;
187 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
188 return 0; /* error but caught downstream */
191 delta_limit = (unsigned long)
192 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
193 if (diffcore_count_changes(src, dst,
194 &src->cnt_data, &dst->cnt_data,
195 delta_limit,
196 &src_copied, &literal_added))
197 return 0;
199 /* How similar are they?
200 * what percentage of material in dst are from source?
202 if (!dst->size)
203 score = 0; /* should not happen */
204 else
205 score = (int)(src_copied * MAX_SCORE / max_size);
206 return score;
209 static void record_rename_pair(int dst_index, int src_index, int score)
211 struct diff_filespec *one, *two, *src, *dst;
212 struct diff_filepair *dp;
214 if (rename_dst[dst_index].pair)
215 die("internal error: dst already matched.");
217 src = rename_src[src_index].one;
218 one = alloc_filespec(src->path);
219 fill_filespec(one, src->sha1, src->mode);
221 dst = rename_dst[dst_index].two;
222 two = alloc_filespec(dst->path);
223 fill_filespec(two, dst->sha1, dst->mode);
225 dp = diff_queue(NULL, one, two);
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 dp->source_stays = rename_src[src_index].src_path_left;
232 rename_dst[dst_index].pair = dp;
236 * We sort the rename similarity matrix with the score, in descending
237 * order (the most similar first).
239 static int score_compare(const void *a_, const void *b_)
241 const struct diff_score *a = a_, *b = b_;
243 if (a->score == b->score)
244 return b->name_score - a->name_score;
246 return b->score - a->score;
249 static int compute_stays(struct diff_queue_struct *q,
250 struct diff_filespec *one)
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 */
261 return 1;
264 void diffcore_rename(struct diff_options *options)
266 int detect_rename = options->detect_rename;
267 int minimum_score = options->rename_score;
268 int rename_limit = options->rename_limit;
269 struct diff_queue_struct *q = &diff_queued_diff;
270 struct diff_queue_struct outq;
271 struct diff_score *mx;
272 int i, j, rename_count, contents_too;
273 int num_create, num_src, dst_cnt;
275 if (!minimum_score)
276 minimum_score = DEFAULT_RENAME_SCORE;
277 rename_count = 0;
279 for (i = 0; i < q->nr; i++) {
280 struct diff_filepair *p = q->queue[i];
281 if (!DIFF_FILE_VALID(p->one)) {
282 if (!DIFF_FILE_VALID(p->two))
283 continue; /* unmerged */
284 else if (options->single_follow &&
285 strcmp(options->single_follow, p->two->path))
286 continue; /* not interested */
287 else
288 locate_rename_dst(p->two, 1);
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.
295 int stays = (p->broken_pair && !p->score);
296 register_rename_src(p->one, stays, p->score);
298 else if (detect_rename == DIFF_DETECT_COPY)
299 register_rename_src(p->one, 1, p->score);
301 if (rename_dst_nr == 0 || rename_src_nr == 0 ||
302 (0 < rename_limit && rename_limit < rename_dst_nr))
303 goto cleanup; /* nothing to do */
305 /* We really want to cull the candidates list early
306 * with cheap tests in order to avoid doing deltas.
307 * The first round matches up the up-to-date entries,
308 * and then during the second round we try to match
309 * cache-dirty entries as well.
311 for (contents_too = 0; contents_too < 2; contents_too++) {
312 for (i = 0; i < rename_dst_nr; i++) {
313 struct diff_filespec *two = rename_dst[i].two;
314 if (rename_dst[i].pair)
315 continue; /* dealt with an earlier round */
316 for (j = 0; j < rename_src_nr; j++) {
317 int k;
318 struct diff_filespec *one = rename_src[j].one;
319 if (!is_exact_match(one, two, contents_too))
320 continue;
322 /* see if there is a basename match, too */
323 for (k = j; k < rename_src_nr; k++) {
324 one = rename_src[k].one;
325 if (basename_same(one, two) &&
326 is_exact_match(one, two,
327 contents_too)) {
328 j = k;
329 break;
333 record_rename_pair(i, j, (int)MAX_SCORE);
334 rename_count++;
335 break; /* we are done with this entry */
340 /* Have we run out the created file pool? If so we can avoid
341 * doing the delta matrix altogether.
343 if (rename_count == rename_dst_nr)
344 goto cleanup;
346 if (minimum_score == MAX_SCORE)
347 goto cleanup;
349 num_create = (rename_dst_nr - rename_count);
350 num_src = rename_src_nr;
351 mx = xmalloc(sizeof(*mx) * num_create * num_src);
352 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
353 int base = dst_cnt * num_src;
354 struct diff_filespec *two = rename_dst[i].two;
355 if (rename_dst[i].pair)
356 continue; /* dealt with exact match already. */
357 for (j = 0; j < rename_src_nr; j++) {
358 struct diff_filespec *one = rename_src[j].one;
359 struct diff_score *m = &mx[base+j];
360 m->src = j;
361 m->dst = i;
362 m->score = estimate_similarity(one, two,
363 minimum_score);
364 m->name_score = basename_same(one, two);
365 diff_free_filespec_data(one);
367 /* We do not need the text anymore */
368 diff_free_filespec_data(two);
369 dst_cnt++;
371 /* cost matrix sorted by most to least similar pair */
372 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
373 for (i = 0; i < num_create * num_src; i++) {
374 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
375 if (dst->pair)
376 continue; /* already done, either exact or fuzzy. */
377 if (mx[i].score < minimum_score)
378 break; /* there is no more usable pair. */
379 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
380 rename_count++;
382 free(mx);
384 cleanup:
385 /* At this point, we have found some renames and copies and they
386 * are recorded in rename_dst. The original list is still in *q.
388 outq.queue = NULL;
389 outq.nr = outq.alloc = 0;
390 for (i = 0; i < q->nr; i++) {
391 struct diff_filepair *p = q->queue[i];
392 struct diff_filepair *pair_to_free = NULL;
394 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
396 * Creation
398 * We would output this create record if it has
399 * not been turned into a rename/copy already.
401 struct diff_rename_dst *dst =
402 locate_rename_dst(p->two, 0);
403 if (dst && dst->pair) {
404 diff_q(&outq, dst->pair);
405 pair_to_free = p;
407 else
408 /* no matching rename/copy source, so
409 * record this as a creation.
411 diff_q(&outq, p);
413 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
415 * Deletion
417 * We would output this delete record if:
419 * (1) this is a broken delete and the counterpart
420 * broken create remains in the output; or
421 * (2) this is not a broken delete, and rename_dst
422 * does not have a rename/copy to move p->one->path
423 * out of existence.
425 * Otherwise, the counterpart broken create
426 * has been turned into a rename-edit; or
427 * delete did not have a matching create to
428 * begin with.
430 if (DIFF_PAIR_BROKEN(p)) {
431 /* broken delete */
432 struct diff_rename_dst *dst =
433 locate_rename_dst(p->one, 0);
434 if (dst && dst->pair)
435 /* counterpart is now rename/copy */
436 pair_to_free = p;
438 else {
439 for (j = 0; j < rename_dst_nr; j++) {
440 if (!rename_dst[j].pair)
441 continue;
442 if (strcmp(rename_dst[j].pair->
443 one->path,
444 p->one->path))
445 continue;
446 break;
448 if (j < rename_dst_nr)
449 /* this path remains */
450 pair_to_free = p;
453 if (pair_to_free)
455 else
456 diff_q(&outq, p);
458 else if (!diff_unmodified_pair(p))
459 /* all the usual ones need to be kept */
460 diff_q(&outq, p);
461 else
462 /* no need to keep unmodified pairs */
463 pair_to_free = p;
465 if (pair_to_free)
466 diff_free_filepair(pair_to_free);
468 diff_debug_queue("done copying original", &outq);
470 free(q->queue);
471 *q = outq;
472 diff_debug_queue("done collapsing", q);
474 /* We need to see which rename source really stays here;
475 * earlier we only checked if the path is left in the result,
476 * but even if a path remains in the result, if that is coming
477 * from copying something else on top of it, then the original
478 * source is lost and does not stay.
480 for (i = 0; i < q->nr; i++) {
481 struct diff_filepair *p = q->queue[i];
482 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
483 /* If one appears as the target of a rename-copy,
484 * then mark p->source_stays = 0; otherwise
485 * leave it as is.
487 p->source_stays = compute_stays(q, p->one);
491 for (i = 0; i < rename_dst_nr; i++) {
492 diff_free_filespec_data(rename_dst[i].two);
493 free(rename_dst[i].two);
496 free(rename_dst);
497 rename_dst = NULL;
498 rename_dst_nr = rename_dst_alloc = 0;
499 free(rename_src);
500 rename_src = NULL;
501 rename_src_nr = rename_src_alloc = 0;
502 return;