]>
Commit | Line | Data |
---|---|---|
427dcb4b JH |
1 | /* |
2 | * Copyright (C) 2005 Junio C Hamano | |
3 | */ | |
4 | #include "cache.h" | |
5 | #include "diff.h" | |
6 | #include "diffcore.h" | |
7 | #include "delta.h" | |
8 | ||
9 | struct diff_rename_pool { | |
10 | struct diff_filespec **s; | |
11 | int nr, alloc; | |
12 | }; | |
13 | ||
14 | static void diff_rename_pool_clear(struct diff_rename_pool *pool) | |
15 | { | |
16 | pool->s = NULL; pool->nr = pool->alloc = 0; | |
17 | } | |
18 | ||
19 | static void diff_rename_pool_add(struct diff_rename_pool *pool, | |
20 | struct diff_filespec *s) | |
21 | { | |
22 | if (S_ISDIR(s->mode)) | |
23 | return; /* rename/copy patch for tree does not make sense. */ | |
24 | ||
25 | if (pool->alloc <= pool->nr) { | |
26 | pool->alloc = alloc_nr(pool->alloc); | |
27 | pool->s = xrealloc(pool->s, | |
28 | sizeof(*(pool->s)) * pool->alloc); | |
29 | } | |
30 | pool->s[pool->nr] = s; | |
31 | pool->nr++; | |
32 | } | |
33 | ||
34 | static int is_exact_match(struct diff_filespec *src, struct diff_filespec *dst) | |
35 | { | |
36 | if (src->sha1_valid && dst->sha1_valid && | |
37 | !memcmp(src->sha1, dst->sha1, 20)) | |
38 | return 1; | |
39 | if (diff_populate_filespec(src) || diff_populate_filespec(dst)) | |
40 | /* this is an error but will be caught downstream */ | |
41 | return 0; | |
42 | if (src->size == dst->size && | |
43 | !memcmp(src->data, dst->data, src->size)) | |
44 | return 1; | |
45 | return 0; | |
46 | } | |
47 | ||
48 | struct diff_score { | |
49 | struct diff_filespec *src; | |
50 | struct diff_filespec *dst; | |
51 | int score; | |
52 | int rank; | |
53 | }; | |
54 | ||
55 | static int estimate_similarity(struct diff_filespec *src, | |
56 | struct diff_filespec *dst, | |
57 | int minimum_score) | |
58 | { | |
59 | /* src points at a file that existed in the original tree (or | |
60 | * optionally a file in the destination tree) and dst points | |
61 | * at a newly created file. They may be quite similar, in which | |
62 | * case we want to say src is renamed to dst or src is copied into | |
63 | * dst, and then some edit has been applied to dst. | |
64 | * | |
65 | * Compare them and return how similar they are, representing | |
66 | * the score as an integer between 0 and 10000, except | |
67 | * where they match exactly it is considered better than anything | |
68 | * else. | |
69 | */ | |
70 | void *delta; | |
58b103f5 | 71 | unsigned long delta_size, base_size; |
427dcb4b JH |
72 | int score; |
73 | ||
74 | delta_size = ((src->size < dst->size) ? | |
75 | (dst->size - src->size) : (src->size - dst->size)); | |
58b103f5 | 76 | base_size = ((src->size < dst->size) ? src->size : dst->size); |
427dcb4b | 77 | |
58b103f5 JH |
78 | /* We would not consider edits that change the file size so |
79 | * drastically. delta_size must be smaller than | |
80 | * minimum_score/MAX_SCORE * min(src->size, dst->size). | |
81 | * Note that base_size == 0 case is handled here already | |
82 | * and the final score computation below would not have a | |
83 | * divide-by-zero issue. | |
427dcb4b | 84 | */ |
58b103f5 | 85 | if (base_size * minimum_score < delta_size * MAX_SCORE) |
427dcb4b JH |
86 | return 0; |
87 | ||
88 | delta = diff_delta(src->data, src->size, | |
89 | dst->data, dst->size, | |
90 | &delta_size); | |
58b103f5 JH |
91 | /* |
92 | * We currently punt here, but we may later end up parsing the | |
93 | * delta to really assess the extent of damage. A big consecutive | |
94 | * remove would produce small delta_size that affects quite a | |
95 | * big portion of the file. | |
96 | */ | |
427dcb4b JH |
97 | free(delta); |
98 | ||
58b103f5 JH |
99 | /* |
100 | * Now we will give some score to it. 100% edit gets 0 points | |
101 | * and 0% edit gets MAX_SCORE points. | |
427dcb4b | 102 | */ |
58b103f5 | 103 | score = MAX_SCORE - (MAX_SCORE * delta_size / base_size); |
427dcb4b JH |
104 | if (score < 0) return 0; |
105 | if (MAX_SCORE < score) return MAX_SCORE; | |
106 | return score; | |
107 | } | |
108 | ||
109 | static void record_rename_pair(struct diff_queue_struct *outq, | |
110 | struct diff_filespec *src, | |
111 | struct diff_filespec *dst, | |
112 | int rank, | |
113 | int score) | |
114 | { | |
115 | /* The rank is used to sort the final output, because there | |
116 | * are certain dependencies. | |
117 | * | |
118 | * - rank #0 depends on deleted ones. | |
119 | * - rank #1 depends on kept files before they are modified. | |
120 | * - rank #2 depends on kept files after they are modified; | |
121 | * currently not used. | |
122 | * | |
123 | * Therefore, the final output order should be: | |
124 | * | |
125 | * 1. rank #0 rename/copy diffs. | |
126 | * 2. deletions in the original. | |
127 | * 3. rank #1 rename/copy diffs. | |
128 | * 4. additions and modifications in the original. | |
129 | * 5. rank #2 rename/copy diffs; currently not used. | |
130 | * | |
131 | * To achieve this sort order, we give xform_work the number | |
132 | * above. | |
133 | */ | |
52e95789 | 134 | struct diff_filepair *dp = diff_queue(outq, src, dst); |
427dcb4b JH |
135 | dp->xfrm_work = (rank * 2 + 1) | (score<<RENAME_SCORE_SHIFT); |
136 | dst->xfrm_flags |= RENAME_DST_MATCHED; | |
137 | } | |
138 | ||
139 | #if 0 | |
140 | static void debug_filespec(struct diff_filespec *s, int x, const char *one) | |
141 | { | |
142 | fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n", | |
143 | x, one, | |
144 | s->path, | |
145 | s->file_valid ? "valid" : "invalid", | |
146 | s->mode, | |
147 | s->sha1_valid ? sha1_to_hex(s->sha1) : ""); | |
148 | fprintf(stderr, "queue[%d] %s size %lu flags %d\n", | |
149 | x, one, | |
150 | s->size, s->xfrm_flags); | |
151 | } | |
152 | ||
52e95789 | 153 | static void debug_filepair(const struct diff_filepair *p, int i) |
427dcb4b JH |
154 | { |
155 | debug_filespec(p->one, i, "one"); | |
156 | debug_filespec(p->two, i, "two"); | |
157 | fprintf(stderr, "pair flags %d, orig order %d, score %d\n", | |
158 | (p->xfrm_work & ((1<<RENAME_SCORE_SHIFT) - 1)), | |
159 | p->orig_order, | |
160 | (p->xfrm_work >> RENAME_SCORE_SHIFT)); | |
161 | } | |
162 | ||
163 | static void debug_queue(const char *msg, struct diff_queue_struct *q) | |
164 | { | |
165 | int i; | |
166 | if (msg) | |
167 | fprintf(stderr, "%s\n", msg); | |
168 | fprintf(stderr, "q->nr = %d\n", q->nr); | |
169 | for (i = 0; i < q->nr; i++) { | |
52e95789 | 170 | struct diff_filepair *p = q->queue[i]; |
427dcb4b JH |
171 | debug_filepair(p, i); |
172 | } | |
173 | } | |
174 | #else | |
175 | #define debug_queue(a,b) do { ; /*nothing*/ } while(0) | |
176 | #endif | |
177 | ||
178 | /* | |
179 | * We sort the outstanding diff entries according to the rank (see | |
180 | * comment at the beginning of record_rename_pair) and tiebreak with | |
181 | * the order in the original input. | |
182 | */ | |
183 | static int rank_compare(const void *a_, const void *b_) | |
184 | { | |
52e95789 JH |
185 | const struct diff_filepair *a = *(const struct diff_filepair **)a_; |
186 | const struct diff_filepair *b = *(const struct diff_filepair **)b_; | |
427dcb4b JH |
187 | int a_rank = a->xfrm_work & ((1<<RENAME_SCORE_SHIFT) - 1); |
188 | int b_rank = b->xfrm_work & ((1<<RENAME_SCORE_SHIFT) - 1); | |
189 | ||
190 | if (a_rank != b_rank) | |
191 | return a_rank - b_rank; | |
192 | return a->orig_order - b->orig_order; | |
193 | } | |
194 | ||
195 | /* | |
196 | * We sort the rename similarity matrix with the score, in descending | |
197 | * order (more similar first). | |
198 | */ | |
199 | static int score_compare(const void *a_, const void *b_) | |
200 | { | |
201 | const struct diff_score *a = a_, *b = b_; | |
202 | return b->score - a->score; | |
203 | } | |
204 | ||
205 | static int needs_to_stay(struct diff_queue_struct *q, int i, | |
206 | struct diff_filespec *it) | |
207 | { | |
208 | /* If it will be used in later entry (either stay or used | |
209 | * as the source of rename/copy), we need to copy, not rename. | |
210 | */ | |
211 | while (i < q->nr) { | |
52e95789 | 212 | struct diff_filepair *p = q->queue[i++]; |
427dcb4b JH |
213 | if (!p->two->file_valid) |
214 | continue; /* removed is fine */ | |
215 | if (strcmp(p->one->path, it->path)) | |
216 | continue; /* not relevant */ | |
217 | ||
218 | /* p has its src set to *it and it is not a delete; | |
219 | * it will be used for in-place change or rename/copy, | |
220 | * so we cannot rename it out. | |
221 | */ | |
222 | return 1; | |
223 | } | |
224 | return 0; | |
225 | } | |
226 | ||
227 | void diff_detect_rename(struct diff_queue_struct *q, | |
228 | int detect_rename, | |
229 | int minimum_score) | |
230 | { | |
231 | struct diff_queue_struct outq; | |
232 | struct diff_rename_pool created, deleted, stay; | |
233 | struct diff_rename_pool *(srcs[2]); | |
234 | struct diff_score *mx; | |
235 | int h, i, j; | |
236 | int num_create, num_src, dst_cnt, src_cnt; | |
237 | ||
238 | outq.queue = NULL; | |
239 | outq.nr = outq.alloc = 0; | |
240 | ||
241 | diff_rename_pool_clear(&created); | |
242 | diff_rename_pool_clear(&deleted); | |
243 | diff_rename_pool_clear(&stay); | |
244 | ||
245 | srcs[0] = &deleted; | |
246 | srcs[1] = &stay; | |
247 | ||
427dcb4b | 248 | for (i = 0; i < q->nr; i++) { |
52e95789 | 249 | struct diff_filepair *p = q->queue[i]; |
427dcb4b JH |
250 | if (!p->one->file_valid) |
251 | if (!p->two->file_valid) | |
252 | continue; /* ignore nonsense */ | |
253 | else | |
254 | diff_rename_pool_add(&created, p->two); | |
255 | else if (!p->two->file_valid) | |
256 | diff_rename_pool_add(&deleted, p->one); | |
257 | else if (1 < detect_rename) /* find copy, too */ | |
258 | diff_rename_pool_add(&stay, p->one); | |
259 | } | |
260 | if (created.nr == 0) | |
261 | goto cleanup; /* nothing to do */ | |
262 | ||
263 | /* We really want to cull the candidates list early | |
264 | * with cheap tests in order to avoid doing deltas. | |
265 | * | |
266 | * With the current callers, we should not have already | |
267 | * matched entries at this point, but it is nonetheless | |
268 | * checked for sanity. | |
269 | */ | |
270 | for (i = 0; i < created.nr; i++) { | |
271 | if (created.s[i]->xfrm_flags & RENAME_DST_MATCHED) | |
272 | continue; /* we have matched exactly already */ | |
273 | for (h = 0; h < sizeof(srcs)/sizeof(srcs[0]); h++) { | |
274 | struct diff_rename_pool *p = srcs[h]; | |
275 | for (j = 0; j < p->nr; j++) { | |
276 | if (!is_exact_match(p->s[j], created.s[i])) | |
277 | continue; | |
278 | record_rename_pair(&outq, | |
279 | p->s[j], created.s[i], h, | |
280 | MAX_SCORE); | |
281 | break; /* we are done with this entry */ | |
282 | } | |
283 | } | |
284 | } | |
285 | debug_queue("done detecting exact", &outq); | |
286 | ||
287 | /* Have we run out the created file pool? If so we can avoid | |
288 | * doing the delta matrix altogether. | |
289 | */ | |
290 | if (outq.nr == created.nr) | |
291 | goto flush_rest; | |
292 | ||
293 | num_create = (created.nr - outq.nr); | |
294 | num_src = deleted.nr + stay.nr; | |
295 | mx = xmalloc(sizeof(*mx) * num_create * num_src); | |
296 | for (dst_cnt = i = 0; i < created.nr; i++) { | |
297 | int base = dst_cnt * num_src; | |
298 | if (created.s[i]->xfrm_flags & RENAME_DST_MATCHED) | |
299 | continue; /* dealt with exact match already. */ | |
300 | for (src_cnt = h = 0; h < sizeof(srcs)/sizeof(srcs[0]); h++) { | |
301 | struct diff_rename_pool *p = srcs[h]; | |
302 | for (j = 0; j < p->nr; j++, src_cnt++) { | |
303 | struct diff_score *m = &mx[base + src_cnt]; | |
304 | m->src = p->s[j]; | |
305 | m->dst = created.s[i]; | |
306 | m->score = estimate_similarity(m->src, m->dst, | |
307 | minimum_score); | |
308 | m->rank = h; | |
309 | } | |
310 | } | |
311 | dst_cnt++; | |
312 | } | |
313 | /* cost matrix sorted by most to least similar pair */ | |
314 | qsort(mx, num_create * num_src, sizeof(*mx), score_compare); | |
315 | for (i = 0; i < num_create * num_src; i++) { | |
316 | if (mx[i].dst->xfrm_flags & RENAME_DST_MATCHED) | |
317 | continue; /* alreayd done, either exact or fuzzy. */ | |
318 | if (mx[i].score < minimum_score) | |
58b103f5 | 319 | break; /* there is not any more diffs applicable. */ |
427dcb4b JH |
320 | record_rename_pair(&outq, |
321 | mx[i].src, mx[i].dst, mx[i].rank, | |
322 | mx[i].score); | |
323 | } | |
324 | free(mx); | |
325 | debug_queue("done detecting fuzzy", &outq); | |
326 | ||
327 | flush_rest: | |
328 | /* At this point, we have found some renames and copies and they | |
329 | * are kept in outq. The original list is still in *q. | |
330 | * | |
331 | * Scan the original list and move them into the outq; we will sort | |
332 | * outq and swap it into the queue supplied to pass that to | |
333 | * downstream, so we assign the sort keys in this loop. | |
334 | * | |
335 | * See comments at the top of record_rename_pair for numbers used | |
336 | * to assign xfrm_work. | |
337 | * | |
52e95789 | 338 | * Note that we have not annotated the diff_filepair with any comment |
427dcb4b JH |
339 | * so there is nothing other than p to free. |
340 | */ | |
341 | for (i = 0; i < q->nr; i++) { | |
52e95789 | 342 | struct diff_filepair *dp, *p = q->queue[i]; |
427dcb4b JH |
343 | if (!p->one->file_valid) { |
344 | if (p->two->file_valid) { | |
345 | /* creation */ | |
346 | dp = diff_queue(&outq, p->one, p->two); | |
347 | dp->xfrm_work = 4; | |
348 | } | |
349 | /* otherwise it is a nonsense; just ignore it */ | |
350 | } | |
351 | else if (!p->two->file_valid) { | |
352 | /* deletion */ | |
353 | dp = diff_queue(&outq, p->one, p->two); | |
354 | dp->xfrm_work = 2; | |
355 | } | |
356 | else { | |
357 | /* modification, or stay as is */ | |
358 | dp = diff_queue(&outq, p->one, p->two); | |
359 | dp->xfrm_work = 4; | |
360 | } | |
361 | free(p); | |
362 | } | |
363 | debug_queue("done copying original", &outq); | |
364 | ||
365 | /* Sort outq */ | |
366 | qsort(outq.queue, outq.nr, sizeof(outq.queue[0]), rank_compare); | |
367 | ||
368 | debug_queue("done sorting", &outq); | |
369 | ||
370 | free(q->queue); | |
371 | q->nr = q->alloc = 0; | |
372 | q->queue = NULL; | |
373 | ||
374 | /* Copy it out to q, removing duplicates. */ | |
375 | for (i = 0; i < outq.nr; i++) { | |
52e95789 | 376 | struct diff_filepair *p = outq.queue[i]; |
427dcb4b JH |
377 | if (!p->one->file_valid) { |
378 | /* created */ | |
379 | if (p->two->xfrm_flags & RENAME_DST_MATCHED) | |
380 | ; /* rename/copy created it already */ | |
381 | else | |
382 | diff_queue(q, p->one, p->two); | |
383 | } | |
384 | else if (!p->two->file_valid) { | |
385 | /* deleted */ | |
386 | if (p->one->xfrm_flags & RENAME_SRC_GONE) | |
387 | ; /* rename/copy deleted it already */ | |
388 | else | |
389 | diff_queue(q, p->one, p->two); | |
390 | } | |
391 | else if (strcmp(p->one->path, p->two->path)) { | |
392 | /* rename or copy */ | |
52e95789 | 393 | struct diff_filepair *dp = |
427dcb4b JH |
394 | diff_queue(q, p->one, p->two); |
395 | int msglen = (strlen(p->one->path) + | |
396 | strlen(p->two->path) + 100); | |
397 | int score = (p->xfrm_work >> RENAME_SCORE_SHIFT); | |
398 | dp->xfrm_msg = xmalloc(msglen); | |
399 | ||
400 | /* if we have a later entry that is a rename/copy | |
401 | * that depends on p->one, then we copy here. | |
402 | * otherwise we rename it. | |
403 | */ | |
404 | if (needs_to_stay(&outq, i+1, p->one)) { | |
405 | /* copy it */ | |
406 | sprintf(dp->xfrm_msg, | |
407 | "similarity index %d%%\n" | |
408 | "copy from %s\n" | |
409 | "copy to %s\n", | |
410 | (int)(0.5 + score * 100 / MAX_SCORE), | |
411 | p->one->path, p->two->path); | |
412 | } | |
413 | else { | |
414 | /* rename it, and mark it as gone. */ | |
415 | p->one->xfrm_flags |= RENAME_SRC_GONE; | |
416 | sprintf(dp->xfrm_msg, | |
417 | "similarity index %d%%\n" | |
418 | "rename old %s\n" | |
419 | "rename new %s\n", | |
420 | (int)(0.5 + score * 100 / MAX_SCORE), | |
421 | p->one->path, p->two->path); | |
422 | } | |
423 | } | |
424 | else | |
425 | /* otherwise it is a modified (or stayed) entry */ | |
426 | diff_queue(q, p->one, p->two); | |
427 | free(p); | |
428 | } | |
429 | ||
430 | free(outq.queue); | |
431 | debug_queue("done collapsing", q); | |
432 | ||
433 | cleanup: | |
434 | free(created.s); | |
435 | free(deleted.s); | |
436 | free(stay.s); | |
437 | return; | |
438 | } |