diffcore_count_changes: pass diffcore_filespec
[git/git.git] / diffcore-rename.c
1 /*
2 * Copyright (C) 2005 Junio C Hamano
3 */
4 #include "cache.h"
5 #include "diff.h"
6 #include "diffcore.h"
7
8 /* Table of rename/copy destinations */
9
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;
15
16 static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
17 int insert_ok)
18 {
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));
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]);
52 }
53
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;
61
62 static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
63 int src_path_left,
64 unsigned short score)
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 }
82
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));
88 }
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]);
97 }
98
99 static int is_exact_match(struct diff_filespec *src,
100 struct diff_filespec *dst,
101 int contents_too)
102 {
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;
120 }
121
122 static 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
137 struct diff_score {
138 int src; /* index in rename_src */
139 int dst; /* index in rename_dst */
140 int score;
141 };
142
143 static int estimate_similarity(struct diff_filespec *src,
144 struct diff_filespec *dst,
145 int minimum_score)
146 {
147 /* src points at a file that existed in the original tree (or
148 * optionally a file in the destination tree) and dst points
149 * at a newly created file. They may be quite similar, in which
150 * case we want to say src is renamed to dst or src is copied into
151 * dst, and then some edit has been applied to dst.
152 *
153 * Compare them and return how similar they are, representing
154 * the score as an integer between 0 and MAX_SCORE.
155 *
156 * When there is an exact match, it is considered a better
157 * match than anything else; the destination does not even
158 * call into this function in that case.
159 */
160 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
161 unsigned long delta_limit;
162 int score;
163
164 /* We deal only with regular files. Symlink renames are handled
165 * only when they are exact matches --- in other words, no edits
166 * after renaming.
167 */
168 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
169 return 0;
170
171 max_size = ((src->size > dst->size) ? src->size : dst->size);
172 base_size = ((src->size < dst->size) ? src->size : dst->size);
173 delta_size = max_size - base_size;
174
175 /* We would not consider edits that change the file size so
176 * drastically. delta_size must be smaller than
177 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
178 *
179 * Note that base_size == 0 case is handled here already
180 * and the final score computation below would not have a
181 * divide-by-zero issue.
182 */
183 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
184 return 0;
185
186 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
187 return 0; /* error but caught downstream */
188
189
190 delta_limit = (unsigned long)
191 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
192 if (diffcore_count_changes(src, dst,
193 &src->cnt_data, &dst->cnt_data,
194 delta_limit,
195 &src_copied, &literal_added))
196 return 0;
197
198 /* How similar are they?
199 * what percentage of material in dst are from source?
200 */
201 if (!dst->size)
202 score = 0; /* should not happen */
203 else {
204 score = (int)(src_copied * MAX_SCORE / max_size);
205 if (basename_same(src, dst))
206 score++;
207 }
208 return score;
209 }
210
211 static void record_rename_pair(int dst_index, int src_index, int score)
212 {
213 struct diff_filespec *one, *two, *src, *dst;
214 struct diff_filepair *dp;
215
216 if (rename_dst[dst_index].pair)
217 die("internal error: dst already matched.");
218
219 src = rename_src[src_index].one;
220 one = alloc_filespec(src->path);
221 fill_filespec(one, src->sha1, src->mode);
222
223 dst = rename_dst[dst_index].two;
224 two = alloc_filespec(dst->path);
225 fill_filespec(two, dst->sha1, dst->mode);
226
227 dp = diff_queue(NULL, one, two);
228 dp->renamed_pair = 1;
229 if (!strcmp(src->path, dst->path))
230 dp->score = rename_src[src_index].score;
231 else
232 dp->score = score;
233 dp->source_stays = rename_src[src_index].src_path_left;
234 rename_dst[dst_index].pair = dp;
235 }
236
237 /*
238 * We sort the rename similarity matrix with the score, in descending
239 * order (the most similar first).
240 */
241 static int score_compare(const void *a_, const void *b_)
242 {
243 const struct diff_score *a = a_, *b = b_;
244 return b->score - a->score;
245 }
246
247 static int compute_stays(struct diff_queue_struct *q,
248 struct diff_filespec *one)
249 {
250 int i;
251 for (i = 0; i < q->nr; i++) {
252 struct diff_filepair *p = q->queue[i];
253 if (strcmp(one->path, p->two->path))
254 continue;
255 if (DIFF_PAIR_RENAME(p)) {
256 return 0; /* something else is renamed into this */
257 }
258 }
259 return 1;
260 }
261
262 void diffcore_rename(struct diff_options *options)
263 {
264 int detect_rename = options->detect_rename;
265 int minimum_score = options->rename_score;
266 int rename_limit = options->rename_limit;
267 struct diff_queue_struct *q = &diff_queued_diff;
268 struct diff_queue_struct outq;
269 struct diff_score *mx;
270 int i, j, rename_count, contents_too;
271 int num_create, num_src, dst_cnt;
272
273 if (!minimum_score)
274 minimum_score = DEFAULT_RENAME_SCORE;
275 rename_count = 0;
276
277 for (i = 0; i < q->nr; i++) {
278 struct diff_filepair *p = q->queue[i];
279 if (!DIFF_FILE_VALID(p->one)) {
280 if (!DIFF_FILE_VALID(p->two))
281 continue; /* unmerged */
282 else if (options->single_follow &&
283 strcmp(options->single_follow, p->two->path))
284 continue; /* not interested */
285 else
286 locate_rename_dst(p->two, 1);
287 }
288 else if (!DIFF_FILE_VALID(p->two)) {
289 /* If the source is a broken "delete", and
290 * they did not really want to get broken,
291 * that means the source actually stays.
292 */
293 int stays = (p->broken_pair && !p->score);
294 register_rename_src(p->one, stays, p->score);
295 }
296 else if (detect_rename == DIFF_DETECT_COPY)
297 register_rename_src(p->one, 1, p->score);
298 }
299 if (rename_dst_nr == 0 || rename_src_nr == 0 ||
300 (0 < rename_limit && rename_limit < rename_dst_nr))
301 goto cleanup; /* nothing to do */
302
303 /* We really want to cull the candidates list early
304 * with cheap tests in order to avoid doing deltas.
305 * The first round matches up the up-to-date entries,
306 * and then during the second round we try to match
307 * cache-dirty entries as well.
308 */
309 for (contents_too = 0; contents_too < 2; contents_too++) {
310 for (i = 0; i < rename_dst_nr; i++) {
311 struct diff_filespec *two = rename_dst[i].two;
312 if (rename_dst[i].pair)
313 continue; /* dealt with an earlier round */
314 for (j = 0; j < rename_src_nr; j++) {
315 int k;
316 struct diff_filespec *one = rename_src[j].one;
317 if (!is_exact_match(one, two, contents_too))
318 continue;
319
320 /* see if there is a basename match, too */
321 for (k = j; k < rename_src_nr; k++) {
322 one = rename_src[k].one;
323 if (basename_same(one, two) &&
324 is_exact_match(one, two,
325 contents_too)) {
326 j = k;
327 break;
328 }
329 }
330
331 record_rename_pair(i, j, (int)MAX_SCORE);
332 rename_count++;
333 break; /* we are done with this entry */
334 }
335 }
336 }
337
338 /* Have we run out the created file pool? If so we can avoid
339 * doing the delta matrix altogether.
340 */
341 if (rename_count == rename_dst_nr)
342 goto cleanup;
343
344 if (minimum_score == MAX_SCORE)
345 goto cleanup;
346
347 num_create = (rename_dst_nr - rename_count);
348 num_src = rename_src_nr;
349 mx = xmalloc(sizeof(*mx) * num_create * num_src);
350 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
351 int base = dst_cnt * num_src;
352 struct diff_filespec *two = rename_dst[i].two;
353 if (rename_dst[i].pair)
354 continue; /* dealt with exact match already. */
355 for (j = 0; j < rename_src_nr; j++) {
356 struct diff_filespec *one = rename_src[j].one;
357 struct diff_score *m = &mx[base+j];
358 m->src = j;
359 m->dst = i;
360 m->score = estimate_similarity(one, two,
361 minimum_score);
362 diff_free_filespec_data(one);
363 }
364 /* We do not need the text anymore */
365 diff_free_filespec_data(two);
366 dst_cnt++;
367 }
368 /* cost matrix sorted by most to least similar pair */
369 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
370 for (i = 0; i < num_create * num_src; i++) {
371 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
372 if (dst->pair)
373 continue; /* already done, either exact or fuzzy. */
374 if (mx[i].score < minimum_score)
375 break; /* there is no more usable pair. */
376 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
377 rename_count++;
378 }
379 free(mx);
380
381 cleanup:
382 /* At this point, we have found some renames and copies and they
383 * are recorded in rename_dst. The original list is still in *q.
384 */
385 outq.queue = NULL;
386 outq.nr = outq.alloc = 0;
387 for (i = 0; i < q->nr; i++) {
388 struct diff_filepair *p = q->queue[i];
389 struct diff_filepair *pair_to_free = NULL;
390
391 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
392 /*
393 * Creation
394 *
395 * We would output this create record if it has
396 * not been turned into a rename/copy already.
397 */
398 struct diff_rename_dst *dst =
399 locate_rename_dst(p->two, 0);
400 if (dst && dst->pair) {
401 diff_q(&outq, dst->pair);
402 pair_to_free = p;
403 }
404 else
405 /* no matching rename/copy source, so
406 * record this as a creation.
407 */
408 diff_q(&outq, p);
409 }
410 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
411 /*
412 * Deletion
413 *
414 * We would output this delete record if:
415 *
416 * (1) this is a broken delete and the counterpart
417 * broken create remains in the output; or
418 * (2) this is not a broken delete, and rename_dst
419 * does not have a rename/copy to move p->one->path
420 * out of existence.
421 *
422 * Otherwise, the counterpart broken create
423 * has been turned into a rename-edit; or
424 * delete did not have a matching create to
425 * begin with.
426 */
427 if (DIFF_PAIR_BROKEN(p)) {
428 /* broken delete */
429 struct diff_rename_dst *dst =
430 locate_rename_dst(p->one, 0);
431 if (dst && dst->pair)
432 /* counterpart is now rename/copy */
433 pair_to_free = p;
434 }
435 else {
436 for (j = 0; j < rename_dst_nr; j++) {
437 if (!rename_dst[j].pair)
438 continue;
439 if (strcmp(rename_dst[j].pair->
440 one->path,
441 p->one->path))
442 continue;
443 break;
444 }
445 if (j < rename_dst_nr)
446 /* this path remains */
447 pair_to_free = p;
448 }
449
450 if (pair_to_free)
451 ;
452 else
453 diff_q(&outq, p);
454 }
455 else if (!diff_unmodified_pair(p))
456 /* all the usual ones need to be kept */
457 diff_q(&outq, p);
458 else
459 /* no need to keep unmodified pairs */
460 pair_to_free = p;
461
462 if (pair_to_free)
463 diff_free_filepair(pair_to_free);
464 }
465 diff_debug_queue("done copying original", &outq);
466
467 free(q->queue);
468 *q = outq;
469 diff_debug_queue("done collapsing", q);
470
471 /* We need to see which rename source really stays here;
472 * earlier we only checked if the path is left in the result,
473 * but even if a path remains in the result, if that is coming
474 * from copying something else on top of it, then the original
475 * source is lost and does not stay.
476 */
477 for (i = 0; i < q->nr; i++) {
478 struct diff_filepair *p = q->queue[i];
479 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
480 /* If one appears as the target of a rename-copy,
481 * then mark p->source_stays = 0; otherwise
482 * leave it as is.
483 */
484 p->source_stays = compute_stays(q, p->one);
485 }
486 }
487
488 for (i = 0; i < rename_dst_nr; i++) {
489 diff_free_filespec_data(rename_dst[i].two);
490 free(rename_dst[i].two);
491 }
492
493 free(rename_dst);
494 rename_dst = NULL;
495 rename_dst_nr = rename_dst_alloc = 0;
496 free(rename_src);
497 rename_src = NULL;
498 rename_src_nr = rename_src_alloc = 0;
499 return;
500 }