diffcore-delta: tweak hashbase value.
[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
JH
48 rename_dst[first].two = alloc_filespec(two->path);
49 fill_filespec(rename_dst[first].two, two->sha1, two->mode);
25d5ea41
JH
50 rename_dst[first].pair = NULL;
51 return &(rename_dst[first]);
427dcb4b
JH
52}
53
15d061b4 54/* Table of rename/copy src files */
25d5ea41
JH
55static struct diff_rename_src {
56 struct diff_filespec *one;
6bac10d8 57 unsigned src_path_left : 1;
25d5ea41
JH
58} *rename_src;
59static int rename_src_nr, rename_src_alloc;
427dcb4b 60
15d061b4 61static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
6bac10d8 62 int src_path_left)
25d5ea41
JH
63{
64 int first, last;
65
66 first = 0;
67 last = rename_src_nr;
68 while (last > first) {
69 int next = (last + first) >> 1;
70 struct diff_rename_src *src = &(rename_src[next]);
71 int cmp = strcmp(one->path, src->one->path);
72 if (!cmp)
73 return src;
74 if (cmp < 0) {
75 last = next;
76 continue;
77 }
78 first = next+1;
79 }
15d061b4 80
25d5ea41
JH
81 /* insert to make it at "first" */
82 if (rename_src_alloc <= rename_src_nr) {
83 rename_src_alloc = alloc_nr(rename_src_alloc);
84 rename_src = xrealloc(rename_src,
85 rename_src_alloc * sizeof(*rename_src));
427dcb4b 86 }
25d5ea41
JH
87 rename_src_nr++;
88 if (first < rename_src_nr)
89 memmove(rename_src + first + 1, rename_src + first,
90 (rename_src_nr - first - 1) * sizeof(*rename_src));
91 rename_src[first].one = one;
6bac10d8 92 rename_src[first].src_path_left = src_path_left;
25d5ea41 93 return &(rename_src[first]);
427dcb4b
JH
94}
95
96static int is_exact_match(struct diff_filespec *src, struct diff_filespec *dst)
97{
98 if (src->sha1_valid && dst->sha1_valid &&
99 !memcmp(src->sha1, dst->sha1, 20))
100 return 1;
f0c6b2a2
JH
101 if (diff_populate_filespec(src, 1) || diff_populate_filespec(dst, 1))
102 return 0;
103 if (src->size != dst->size)
104 return 0;
105 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
427dcb4b
JH
106 return 0;
107 if (src->size == dst->size &&
108 !memcmp(src->data, dst->data, src->size))
109 return 1;
110 return 0;
111}
112
113struct diff_score {
25d5ea41
JH
114 int src; /* index in rename_src */
115 int dst; /* index in rename_dst */
427dcb4b 116 int score;
427dcb4b
JH
117};
118
119static int estimate_similarity(struct diff_filespec *src,
120 struct diff_filespec *dst,
121 int minimum_score)
122{
123 /* src points at a file that existed in the original tree (or
124 * optionally a file in the destination tree) and dst points
125 * at a newly created file. They may be quite similar, in which
126 * case we want to say src is renamed to dst or src is copied into
127 * dst, and then some edit has been applied to dst.
128 *
129 * Compare them and return how similar they are, representing
f0c6b2a2
JH
130 * the score as an integer between 0 and MAX_SCORE.
131 *
132 * When there is an exact match, it is considered a better
133 * match than anything else; the destination does not even
134 * call into this function in that case.
427dcb4b 135 */
355e76a4 136 unsigned long delta_size, base_size, src_copied, literal_added;
75c660ac 137 unsigned long delta_limit;
427dcb4b
JH
138 int score;
139
60896c7b
JH
140 /* We deal only with regular files. Symlink renames are handled
141 * only when they are exact matches --- in other words, no edits
142 * after renaming.
143 */
144 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
145 return 0;
146
427dcb4b
JH
147 delta_size = ((src->size < dst->size) ?
148 (dst->size - src->size) : (src->size - dst->size));
58b103f5 149 base_size = ((src->size < dst->size) ? src->size : dst->size);
427dcb4b 150
58b103f5
JH
151 /* We would not consider edits that change the file size so
152 * drastically. delta_size must be smaller than
cd1870ed 153 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
f0c6b2a2 154 *
58b103f5
JH
155 * Note that base_size == 0 case is handled here already
156 * and the final score computation below would not have a
157 * divide-by-zero issue.
427dcb4b 158 */
cd1870ed 159 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
427dcb4b
JH
160 return 0;
161
f0c6b2a2
JH
162 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
163 return 0; /* error but caught downstream */
164
85976974 165
65416758
JH
166 delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE;
167 if (diffcore_count_changes(src->data, src->size,
168 dst->data, dst->size,
c06c7966 169 &src->cnt_data, &dst->cnt_data,
65416758
JH
170 delta_limit,
171 &src_copied, &literal_added))
85976974 172 return 0;
355e76a4 173
1706306a
JH
174 /* How similar are they?
175 * what percentage of material in dst are from source?
427dcb4b 176 */
1706306a
JH
177 if (dst->size < src_copied)
178 score = MAX_SCORE;
179 else if (!dst->size)
180 score = 0; /* should not happen */
181 else
182 score = src_copied * MAX_SCORE / dst->size;
427dcb4b
JH
183 return score;
184}
185
5098bafb 186static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 187{
25d5ea41
JH
188 struct diff_filespec *one, *two, *src, *dst;
189 struct diff_filepair *dp;
f7c1512a 190
25d5ea41
JH
191 if (rename_dst[dst_index].pair)
192 die("internal error: dst already matched.");
427dcb4b 193
25d5ea41
JH
194 src = rename_src[src_index].one;
195 one = alloc_filespec(src->path);
196 fill_filespec(one, src->sha1, src->mode);
427dcb4b 197
25d5ea41
JH
198 dst = rename_dst[dst_index].two;
199 two = alloc_filespec(dst->path);
200 fill_filespec(two, dst->sha1, dst->mode);
427dcb4b 201
5098bafb 202 dp = diff_queue(NULL, one, two);
01c4e70f 203 dp->score = score;
6bac10d8 204 dp->source_stays = rename_src[src_index].src_path_left;
25d5ea41 205 rename_dst[dst_index].pair = dp;
427dcb4b
JH
206}
207
208/*
209 * We sort the rename similarity matrix with the score, in descending
15d061b4 210 * order (the most similar first).
427dcb4b
JH
211 */
212static int score_compare(const void *a_, const void *b_)
213{
214 const struct diff_score *a = a_, *b = b_;
215 return b->score - a->score;
216}
217
6bac10d8
JH
218static int compute_stays(struct diff_queue_struct *q,
219 struct diff_filespec *one)
220{
221 int i;
222 for (i = 0; i < q->nr; i++) {
223 struct diff_filepair *p = q->queue[i];
224 if (strcmp(one->path, p->two->path))
225 continue;
226 if (DIFF_PAIR_RENAME(p)) {
227 return 0; /* something else is renamed into this */
228 }
229 }
230 return 1;
231}
232
8082d8d3 233void diffcore_rename(struct diff_options *options)
427dcb4b 234{
8082d8d3
JH
235 int detect_rename = options->detect_rename;
236 int minimum_score = options->rename_score;
237 int rename_limit = options->rename_limit;
38c6f780 238 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 239 struct diff_queue_struct outq;
427dcb4b 240 struct diff_score *mx;
5098bafb 241 int i, j, rename_count;
25d5ea41 242 int num_create, num_src, dst_cnt;
427dcb4b 243
26dee0ad 244 if (!minimum_score)
f345b0a0 245 minimum_score = DEFAULT_RENAME_SCORE;
5098bafb 246 rename_count = 0;
427dcb4b 247
427dcb4b 248 for (i = 0; i < q->nr; i++) {
52e95789 249 struct diff_filepair *p = q->queue[i];
81e50eab
JH
250 if (!DIFF_FILE_VALID(p->one))
251 if (!DIFF_FILE_VALID(p->two))
60896c7b 252 continue; /* unmerged */
427dcb4b 253 else
25d5ea41 254 locate_rename_dst(p->two, 1);
2210100a
JH
255 else if (!DIFF_FILE_VALID(p->two)) {
256 /* If the source is a broken "delete", and
257 * they did not really want to get broken,
258 * that means the source actually stays.
259 */
260 int stays = (p->broken_pair && !p->score);
261 register_rename_src(p->one, stays);
262 }
15d061b4
JH
263 else if (detect_rename == DIFF_DETECT_COPY)
264 register_rename_src(p->one, 1);
427dcb4b 265 }
7d6fb370 266 if (rename_dst_nr == 0 || rename_src_nr == 0 ||
3299c6f6 267 (0 < rename_limit && rename_limit < rename_dst_nr))
427dcb4b
JH
268 goto cleanup; /* nothing to do */
269
270 /* We really want to cull the candidates list early
271 * with cheap tests in order to avoid doing deltas.
427dcb4b 272 */
25d5ea41
JH
273 for (i = 0; i < rename_dst_nr; i++) {
274 struct diff_filespec *two = rename_dst[i].two;
275 for (j = 0; j < rename_src_nr; j++) {
276 struct diff_filespec *one = rename_src[j].one;
277 if (!is_exact_match(one, two))
278 continue;
5098bafb
JH
279 record_rename_pair(i, j, MAX_SCORE);
280 rename_count++;
25d5ea41 281 break; /* we are done with this entry */
427dcb4b
JH
282 }
283 }
427dcb4b
JH
284
285 /* Have we run out the created file pool? If so we can avoid
286 * doing the delta matrix altogether.
287 */
5098bafb 288 if (rename_count == rename_dst_nr)
15d061b4 289 goto cleanup;
427dcb4b 290
9f70b806
JH
291 if (minimum_score == MAX_SCORE)
292 goto cleanup;
293
5098bafb 294 num_create = (rename_dst_nr - rename_count);
25d5ea41 295 num_src = rename_src_nr;
427dcb4b 296 mx = xmalloc(sizeof(*mx) * num_create * num_src);
25d5ea41 297 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
427dcb4b 298 int base = dst_cnt * num_src;
25d5ea41
JH
299 struct diff_filespec *two = rename_dst[i].two;
300 if (rename_dst[i].pair)
427dcb4b 301 continue; /* dealt with exact match already. */
25d5ea41
JH
302 for (j = 0; j < rename_src_nr; j++) {
303 struct diff_filespec *one = rename_src[j].one;
304 struct diff_score *m = &mx[base+j];
305 m->src = j;
306 m->dst = i;
307 m->score = estimate_similarity(one, two,
308 minimum_score);
427dcb4b 309 }
2821104d
JH
310 /* We do not need the text anymore */
311 diff_free_filespec_data(two);
427dcb4b
JH
312 dst_cnt++;
313 }
314 /* cost matrix sorted by most to least similar pair */
315 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
316 for (i = 0; i < num_create * num_src; i++) {
25d5ea41
JH
317 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
318 if (dst->pair)
319 continue; /* already done, either exact or fuzzy. */
427dcb4b 320 if (mx[i].score < minimum_score)
15d061b4 321 break; /* there is no more usable pair. */
5098bafb
JH
322 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
323 rename_count++;
427dcb4b
JH
324 }
325 free(mx);
427dcb4b 326
15d061b4 327 cleanup:
427dcb4b 328 /* At this point, we have found some renames and copies and they
5098bafb 329 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 330 */
25d5ea41
JH
331 outq.queue = NULL;
332 outq.nr = outq.alloc = 0;
427dcb4b 333 for (i = 0; i < q->nr; i++) {
25d5ea41 334 struct diff_filepair *p = q->queue[i];
25d5ea41
JH
335 struct diff_filepair *pair_to_free = NULL;
336
2cd68882
JH
337 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
338 /*
339 * Creation
340 *
341 * We would output this create record if it has
342 * not been turned into a rename/copy already.
343 */
344 struct diff_rename_dst *dst =
345 locate_rename_dst(p->two, 0);
346 if (dst && dst->pair) {
25d5ea41
JH
347 diff_q(&outq, dst->pair);
348 pair_to_free = p;
349 }
350 else
2cd68882
JH
351 /* no matching rename/copy source, so
352 * record this as a creation.
25d5ea41
JH
353 */
354 diff_q(&outq, p);
427dcb4b 355 }
2cd68882
JH
356 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
357 /*
358 * Deletion
359 *
f345b0a0
JH
360 * We would output this delete record if:
361 *
362 * (1) this is a broken delete and the counterpart
363 * broken create remains in the output; or
5098bafb
JH
364 * (2) this is not a broken delete, and rename_dst
365 * does not have a rename/copy to move p->one->path
366 * out of existence.
f345b0a0
JH
367 *
368 * Otherwise, the counterpart broken create
369 * has been turned into a rename-edit; or
370 * delete did not have a matching create to
371 * begin with.
2cd68882 372 */
f345b0a0
JH
373 if (DIFF_PAIR_BROKEN(p)) {
374 /* broken delete */
375 struct diff_rename_dst *dst =
376 locate_rename_dst(p->one, 0);
377 if (dst && dst->pair)
378 /* counterpart is now rename/copy */
379 pair_to_free = p;
380 }
381 else {
5098bafb
JH
382 for (j = 0; j < rename_dst_nr; j++) {
383 if (!rename_dst[j].pair)
384 continue;
385 if (strcmp(rename_dst[j].pair->
386 one->path,
387 p->one->path))
388 continue;
389 break;
390 }
391 if (j < rename_dst_nr)
f345b0a0
JH
392 /* this path remains */
393 pair_to_free = p;
394 }
2cd68882
JH
395
396 if (pair_to_free)
397 ;
398 else
399 diff_q(&outq, p);
400 }
25d5ea41 401 else if (!diff_unmodified_pair(p))
15d061b4 402 /* all the usual ones need to be kept */
25d5ea41 403 diff_q(&outq, p);
15d061b4
JH
404 else
405 /* no need to keep unmodified pairs */
406 pair_to_free = p;
407
226406f6
JH
408 if (pair_to_free)
409 diff_free_filepair(pair_to_free);
427dcb4b 410 }
25d5ea41 411 diff_debug_queue("done copying original", &outq);
427dcb4b 412
25d5ea41
JH
413 free(q->queue);
414 *q = outq;
415 diff_debug_queue("done collapsing", q);
427dcb4b 416
6bac10d8
JH
417 /* We need to see which rename source really stays here;
418 * earlier we only checked if the path is left in the result,
419 * but even if a path remains in the result, if that is coming
420 * from copying something else on top of it, then the original
421 * source is lost and does not stay.
422 */
423 for (i = 0; i < q->nr; i++) {
424 struct diff_filepair *p = q->queue[i];
425 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
426 /* If one appears as the target of a rename-copy,
427 * then mark p->source_stays = 0; otherwise
428 * leave it as is.
429 */
430 p->source_stays = compute_stays(q, p->one);
431 }
432 }
433
5098bafb
JH
434 for (i = 0; i < rename_dst_nr; i++) {
435 diff_free_filespec_data(rename_dst[i].two);
436 free(rename_dst[i].two);
437 }
438
25d5ea41
JH
439 free(rename_dst);
440 rename_dst = NULL;
441 rename_dst_nr = rename_dst_alloc = 0;
442 free(rename_src);
443 rename_src = NULL;
444 rename_src_nr = rename_src_alloc = 0;
427dcb4b
JH
445 return;
446}