[PATCH] Diffcore updates.
[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"
7#include "delta.h"
8
9struct diff_rename_pool {
10 struct diff_filespec **s;
11 int nr, alloc;
12};
13
14static void diff_rename_pool_clear(struct diff_rename_pool *pool)
15{
16 pool->s = NULL; pool->nr = pool->alloc = 0;
17}
18
19static 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
34static 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
48struct diff_score {
49 struct diff_filespec *src;
50 struct diff_filespec *dst;
51 int score;
52 int rank;
53};
54
55static 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
cd1870ed 80 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
58b103f5
JH
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 */
cd1870ed 85 if (base_size * (MAX_SCORE-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
109static 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
140static 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,
81e50eab 145 DIFF_FILE_VALID(s) ? "valid" : "invalid",
427dcb4b
JH
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 153static 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
163static 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 */
183static 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 */
199static 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
205static 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++];
81e50eab 213 if (!DIFF_FILE_VALID(p->two))
427dcb4b
JH
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
6b14d7fa
JH
227int diff_scoreopt_parse(const char *opt)
228{
229 int diglen, num, scale, i;
230 if (opt[0] != '-' || (opt[1] != 'M' && opt[1] != 'C'))
231 return -1; /* that is not a -M nor -C option */
232 diglen = strspn(opt+2, "0123456789");
233 if (diglen == 0 || strlen(opt+2) != diglen)
234 return 0; /* use default */
235 sscanf(opt+2, "%d", &num);
236 for (i = 0, scale = 1; i < diglen; i++)
237 scale *= 10;
238
239 /* user says num divided by scale and we say internally that
240 * is MAX_SCORE * num / scale.
241 */
242 return MAX_SCORE * num / scale;
243}
244
245void diffcore_rename(int detect_rename, int minimum_score)
427dcb4b 246{
38c6f780 247 struct diff_queue_struct *q = &diff_queued_diff;
427dcb4b
JH
248 struct diff_queue_struct outq;
249 struct diff_rename_pool created, deleted, stay;
250 struct diff_rename_pool *(srcs[2]);
251 struct diff_score *mx;
252 int h, i, j;
253 int num_create, num_src, dst_cnt, src_cnt;
254
26dee0ad
JH
255 if (!minimum_score)
256 minimum_score = DEFAULT_MINIMUM_SCORE;
427dcb4b
JH
257 outq.queue = NULL;
258 outq.nr = outq.alloc = 0;
259
260 diff_rename_pool_clear(&created);
261 diff_rename_pool_clear(&deleted);
262 diff_rename_pool_clear(&stay);
263
264 srcs[0] = &deleted;
265 srcs[1] = &stay;
266
427dcb4b 267 for (i = 0; i < q->nr; i++) {
52e95789 268 struct diff_filepair *p = q->queue[i];
81e50eab
JH
269 if (!DIFF_FILE_VALID(p->one))
270 if (!DIFF_FILE_VALID(p->two))
427dcb4b
JH
271 continue; /* ignore nonsense */
272 else
273 diff_rename_pool_add(&created, p->two);
81e50eab 274 else if (!DIFF_FILE_VALID(p->two))
427dcb4b
JH
275 diff_rename_pool_add(&deleted, p->one);
276 else if (1 < detect_rename) /* find copy, too */
277 diff_rename_pool_add(&stay, p->one);
278 }
279 if (created.nr == 0)
280 goto cleanup; /* nothing to do */
281
282 /* We really want to cull the candidates list early
283 * with cheap tests in order to avoid doing deltas.
284 *
285 * With the current callers, we should not have already
286 * matched entries at this point, but it is nonetheless
287 * checked for sanity.
288 */
289 for (i = 0; i < created.nr; i++) {
290 if (created.s[i]->xfrm_flags & RENAME_DST_MATCHED)
291 continue; /* we have matched exactly already */
292 for (h = 0; h < sizeof(srcs)/sizeof(srcs[0]); h++) {
293 struct diff_rename_pool *p = srcs[h];
294 for (j = 0; j < p->nr; j++) {
295 if (!is_exact_match(p->s[j], created.s[i]))
296 continue;
297 record_rename_pair(&outq,
298 p->s[j], created.s[i], h,
299 MAX_SCORE);
300 break; /* we are done with this entry */
301 }
302 }
303 }
304 debug_queue("done detecting exact", &outq);
305
306 /* Have we run out the created file pool? If so we can avoid
307 * doing the delta matrix altogether.
308 */
309 if (outq.nr == created.nr)
310 goto flush_rest;
311
312 num_create = (created.nr - outq.nr);
313 num_src = deleted.nr + stay.nr;
314 mx = xmalloc(sizeof(*mx) * num_create * num_src);
315 for (dst_cnt = i = 0; i < created.nr; i++) {
316 int base = dst_cnt * num_src;
317 if (created.s[i]->xfrm_flags & RENAME_DST_MATCHED)
318 continue; /* dealt with exact match already. */
319 for (src_cnt = h = 0; h < sizeof(srcs)/sizeof(srcs[0]); h++) {
320 struct diff_rename_pool *p = srcs[h];
321 for (j = 0; j < p->nr; j++, src_cnt++) {
322 struct diff_score *m = &mx[base + src_cnt];
323 m->src = p->s[j];
324 m->dst = created.s[i];
325 m->score = estimate_similarity(m->src, m->dst,
326 minimum_score);
327 m->rank = h;
328 }
329 }
330 dst_cnt++;
331 }
332 /* cost matrix sorted by most to least similar pair */
333 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
334 for (i = 0; i < num_create * num_src; i++) {
335 if (mx[i].dst->xfrm_flags & RENAME_DST_MATCHED)
336 continue; /* alreayd done, either exact or fuzzy. */
337 if (mx[i].score < minimum_score)
58b103f5 338 break; /* there is not any more diffs applicable. */
427dcb4b
JH
339 record_rename_pair(&outq,
340 mx[i].src, mx[i].dst, mx[i].rank,
341 mx[i].score);
342 }
343 free(mx);
344 debug_queue("done detecting fuzzy", &outq);
345
346 flush_rest:
347 /* At this point, we have found some renames and copies and they
348 * are kept in outq. The original list is still in *q.
349 *
350 * Scan the original list and move them into the outq; we will sort
351 * outq and swap it into the queue supplied to pass that to
352 * downstream, so we assign the sort keys in this loop.
353 *
354 * See comments at the top of record_rename_pair for numbers used
355 * to assign xfrm_work.
356 *
52e95789 357 * Note that we have not annotated the diff_filepair with any comment
427dcb4b
JH
358 * so there is nothing other than p to free.
359 */
360 for (i = 0; i < q->nr; i++) {
52e95789 361 struct diff_filepair *dp, *p = q->queue[i];
81e50eab
JH
362 if (!DIFF_FILE_VALID(p->one)) {
363 if (DIFF_FILE_VALID(p->two)) {
427dcb4b
JH
364 /* creation */
365 dp = diff_queue(&outq, p->one, p->two);
366 dp->xfrm_work = 4;
367 }
368 /* otherwise it is a nonsense; just ignore it */
369 }
81e50eab 370 else if (!DIFF_FILE_VALID(p->two)) {
427dcb4b
JH
371 /* deletion */
372 dp = diff_queue(&outq, p->one, p->two);
373 dp->xfrm_work = 2;
374 }
375 else {
376 /* modification, or stay as is */
377 dp = diff_queue(&outq, p->one, p->two);
378 dp->xfrm_work = 4;
379 }
380 free(p);
381 }
382 debug_queue("done copying original", &outq);
383
384 /* Sort outq */
385 qsort(outq.queue, outq.nr, sizeof(outq.queue[0]), rank_compare);
386
387 debug_queue("done sorting", &outq);
388
389 free(q->queue);
390 q->nr = q->alloc = 0;
391 q->queue = NULL;
392
393 /* Copy it out to q, removing duplicates. */
394 for (i = 0; i < outq.nr; i++) {
52e95789 395 struct diff_filepair *p = outq.queue[i];
81e50eab 396 if (!DIFF_FILE_VALID(p->one)) {
427dcb4b
JH
397 /* created */
398 if (p->two->xfrm_flags & RENAME_DST_MATCHED)
399 ; /* rename/copy created it already */
400 else
401 diff_queue(q, p->one, p->two);
402 }
81e50eab 403 else if (!DIFF_FILE_VALID(p->two)) {
427dcb4b
JH
404 /* deleted */
405 if (p->one->xfrm_flags & RENAME_SRC_GONE)
406 ; /* rename/copy deleted it already */
407 else
408 diff_queue(q, p->one, p->two);
409 }
410 else if (strcmp(p->one->path, p->two->path)) {
411 /* rename or copy */
52e95789 412 struct diff_filepair *dp =
427dcb4b
JH
413 diff_queue(q, p->one, p->two);
414 int msglen = (strlen(p->one->path) +
415 strlen(p->two->path) + 100);
416 int score = (p->xfrm_work >> RENAME_SCORE_SHIFT);
417 dp->xfrm_msg = xmalloc(msglen);
418
419 /* if we have a later entry that is a rename/copy
420 * that depends on p->one, then we copy here.
421 * otherwise we rename it.
422 */
423 if (needs_to_stay(&outq, i+1, p->one)) {
424 /* copy it */
425 sprintf(dp->xfrm_msg,
426 "similarity index %d%%\n"
427 "copy from %s\n"
428 "copy to %s\n",
429 (int)(0.5 + score * 100 / MAX_SCORE),
430 p->one->path, p->two->path);
431 }
432 else {
433 /* rename it, and mark it as gone. */
434 p->one->xfrm_flags |= RENAME_SRC_GONE;
435 sprintf(dp->xfrm_msg,
436 "similarity index %d%%\n"
437 "rename old %s\n"
438 "rename new %s\n",
439 (int)(0.5 + score * 100 / MAX_SCORE),
440 p->one->path, p->two->path);
441 }
442 }
443 else
444 /* otherwise it is a modified (or stayed) entry */
445 diff_queue(q, p->one, p->two);
446 free(p);
447 }
448
449 free(outq.queue);
450 debug_queue("done collapsing", q);
451
452 cleanup:
453 free(created.s);
454 free(deleted.s);
455 free(stay.s);
456 return;
457}