git-pickaxe: work properly in a subdirectory.
[git/git.git] / diffcore-rename.c
CommitLineData
427dcb4b
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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
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16static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
17 int insert_ok)
427dcb4b 18{
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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));
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48 rename_dst[first].two = alloc_filespec(two->path);
49 fill_filespec(rename_dst[first].two, two->sha1, two->mode);
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50 rename_dst[first].pair = NULL;
51 return &(rename_dst[first]);
427dcb4b
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52}
53
15d061b4 54/* Table of rename/copy src files */
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55static struct diff_rename_src {
56 struct diff_filespec *one;
fc580719 57 unsigned short score; /* to remember the break score */
6bac10d8 58 unsigned src_path_left : 1;
25d5ea41
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59} *rename_src;
60static int rename_src_nr, rename_src_alloc;
427dcb4b 61
15d061b4 62static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
fc580719
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63 int src_path_left,
64 unsigned short score)
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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 }
15d061b4 82
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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));
427dcb4b 88 }
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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;
fc580719 94 rename_src[first].score = score;
6bac10d8 95 rename_src[first].src_path_left = src_path_left;
25d5ea41 96 return &(rename_src[first]);
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97}
98
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99static int is_exact_match(struct diff_filespec *src,
100 struct diff_filespec *dst,
101 int contents_too)
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102{
103 if (src->sha1_valid && dst->sha1_valid &&
a89fccd2 104 !hashcmp(src->sha1, dst->sha1))
427dcb4b 105 return 1;
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106 if (!contents_too)
107 return 0;
f0c6b2a2
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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 (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
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113 return 0;
114 if (src->size == dst->size &&
115 !memcmp(src->data, dst->data, src->size))
116 return 1;
117 return 0;
118}
119
120struct diff_score {
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121 int src; /* index in rename_src */
122 int dst; /* index in rename_dst */
427dcb4b 123 int score;
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124};
125
126static int estimate_similarity(struct diff_filespec *src,
127 struct diff_filespec *dst,
128 int minimum_score)
129{
130 /* src points at a file that existed in the original tree (or
131 * optionally a file in the destination tree) and dst points
132 * at a newly created file. They may be quite similar, in which
133 * case we want to say src is renamed to dst or src is copied into
134 * dst, and then some edit has been applied to dst.
135 *
136 * Compare them and return how similar they are, representing
f0c6b2a2
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137 * the score as an integer between 0 and MAX_SCORE.
138 *
139 * When there is an exact match, it is considered a better
140 * match than anything else; the destination does not even
141 * call into this function in that case.
427dcb4b 142 */
90bd932c 143 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
75c660ac 144 unsigned long delta_limit;
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145 int score;
146
60896c7b
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147 /* We deal only with regular files. Symlink renames are handled
148 * only when they are exact matches --- in other words, no edits
149 * after renaming.
150 */
151 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
152 return 0;
153
90bd932c 154 max_size = ((src->size > dst->size) ? src->size : dst->size);
58b103f5 155 base_size = ((src->size < dst->size) ? src->size : dst->size);
90bd932c 156 delta_size = max_size - base_size;
427dcb4b 157
58b103f5
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158 /* We would not consider edits that change the file size so
159 * drastically. delta_size must be smaller than
cd1870ed 160 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
f0c6b2a2 161 *
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162 * Note that base_size == 0 case is handled here already
163 * and the final score computation below would not have a
164 * divide-by-zero issue.
427dcb4b 165 */
cd1870ed 166 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
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167 return 0;
168
f0c6b2a2
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169 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
170 return 0; /* error but caught downstream */
171
85976974 172
65416758
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173 delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE;
174 if (diffcore_count_changes(src->data, src->size,
175 dst->data, dst->size,
c06c7966 176 &src->cnt_data, &dst->cnt_data,
65416758
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177 delta_limit,
178 &src_copied, &literal_added))
85976974 179 return 0;
355e76a4 180
1706306a
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181 /* How similar are they?
182 * what percentage of material in dst are from source?
427dcb4b 183 */
90bd932c 184 if (!dst->size)
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185 score = 0; /* should not happen */
186 else
90bd932c 187 score = src_copied * MAX_SCORE / max_size;
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188 return score;
189}
190
5098bafb 191static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 192{
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193 struct diff_filespec *one, *two, *src, *dst;
194 struct diff_filepair *dp;
f7c1512a 195
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196 if (rename_dst[dst_index].pair)
197 die("internal error: dst already matched.");
427dcb4b 198
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199 src = rename_src[src_index].one;
200 one = alloc_filespec(src->path);
201 fill_filespec(one, src->sha1, src->mode);
427dcb4b 202
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203 dst = rename_dst[dst_index].two;
204 two = alloc_filespec(dst->path);
205 fill_filespec(two, dst->sha1, dst->mode);
427dcb4b 206
5098bafb 207 dp = diff_queue(NULL, one, two);
ef677686 208 dp->renamed_pair = 1;
fc580719
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209 if (!strcmp(src->path, dst->path))
210 dp->score = rename_src[src_index].score;
211 else
212 dp->score = score;
6bac10d8 213 dp->source_stays = rename_src[src_index].src_path_left;
25d5ea41 214 rename_dst[dst_index].pair = dp;
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215}
216
217/*
218 * We sort the rename similarity matrix with the score, in descending
15d061b4 219 * order (the most similar first).
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220 */
221static int score_compare(const void *a_, const void *b_)
222{
223 const struct diff_score *a = a_, *b = b_;
224 return b->score - a->score;
225}
226
6bac10d8
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227static int compute_stays(struct diff_queue_struct *q,
228 struct diff_filespec *one)
229{
230 int i;
231 for (i = 0; i < q->nr; i++) {
232 struct diff_filepair *p = q->queue[i];
233 if (strcmp(one->path, p->two->path))
234 continue;
235 if (DIFF_PAIR_RENAME(p)) {
236 return 0; /* something else is renamed into this */
237 }
238 }
239 return 1;
240}
241
8082d8d3 242void diffcore_rename(struct diff_options *options)
427dcb4b 243{
8082d8d3
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244 int detect_rename = options->detect_rename;
245 int minimum_score = options->rename_score;
246 int rename_limit = options->rename_limit;
38c6f780 247 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 248 struct diff_queue_struct outq;
427dcb4b 249 struct diff_score *mx;
17e6019a 250 int i, j, rename_count, contents_too;
25d5ea41 251 int num_create, num_src, dst_cnt;
427dcb4b 252
26dee0ad 253 if (!minimum_score)
f345b0a0 254 minimum_score = DEFAULT_RENAME_SCORE;
5098bafb 255 rename_count = 0;
427dcb4b 256
427dcb4b 257 for (i = 0; i < q->nr; i++) {
52e95789 258 struct diff_filepair *p = q->queue[i];
81e50eab
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259 if (!DIFF_FILE_VALID(p->one))
260 if (!DIFF_FILE_VALID(p->two))
60896c7b 261 continue; /* unmerged */
427dcb4b 262 else
25d5ea41 263 locate_rename_dst(p->two, 1);
2210100a
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264 else if (!DIFF_FILE_VALID(p->two)) {
265 /* If the source is a broken "delete", and
266 * they did not really want to get broken,
267 * that means the source actually stays.
268 */
269 int stays = (p->broken_pair && !p->score);
fc580719 270 register_rename_src(p->one, stays, p->score);
2210100a 271 }
15d061b4 272 else if (detect_rename == DIFF_DETECT_COPY)
fc580719 273 register_rename_src(p->one, 1, p->score);
427dcb4b 274 }
7d6fb370 275 if (rename_dst_nr == 0 || rename_src_nr == 0 ||
3299c6f6 276 (0 < rename_limit && rename_limit < rename_dst_nr))
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277 goto cleanup; /* nothing to do */
278
279 /* We really want to cull the candidates list early
280 * with cheap tests in order to avoid doing deltas.
17e6019a
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281 * The first round matches up the up-to-date entries,
282 * and then during the second round we try to match
283 * cache-dirty entries as well.
427dcb4b 284 */
17e6019a
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285 for (contents_too = 0; contents_too < 2; contents_too++) {
286 for (i = 0; i < rename_dst_nr; i++) {
287 struct diff_filespec *two = rename_dst[i].two;
288 if (rename_dst[i].pair)
289 continue; /* dealt with an earlier round */
290 for (j = 0; j < rename_src_nr; j++) {
291 struct diff_filespec *one = rename_src[j].one;
292 if (!is_exact_match(one, two, contents_too))
293 continue;
294 record_rename_pair(i, j, MAX_SCORE);
295 rename_count++;
296 break; /* we are done with this entry */
297 }
427dcb4b
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298 }
299 }
427dcb4b
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300
301 /* Have we run out the created file pool? If so we can avoid
302 * doing the delta matrix altogether.
303 */
5098bafb 304 if (rename_count == rename_dst_nr)
15d061b4 305 goto cleanup;
427dcb4b 306
9f70b806
JH
307 if (minimum_score == MAX_SCORE)
308 goto cleanup;
309
5098bafb 310 num_create = (rename_dst_nr - rename_count);
25d5ea41 311 num_src = rename_src_nr;
427dcb4b 312 mx = xmalloc(sizeof(*mx) * num_create * num_src);
25d5ea41 313 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
427dcb4b 314 int base = dst_cnt * num_src;
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315 struct diff_filespec *two = rename_dst[i].two;
316 if (rename_dst[i].pair)
427dcb4b 317 continue; /* dealt with exact match already. */
25d5ea41
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318 for (j = 0; j < rename_src_nr; j++) {
319 struct diff_filespec *one = rename_src[j].one;
320 struct diff_score *m = &mx[base+j];
321 m->src = j;
322 m->dst = i;
323 m->score = estimate_similarity(one, two,
324 minimum_score);
427dcb4b 325 }
2821104d
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326 /* We do not need the text anymore */
327 diff_free_filespec_data(two);
427dcb4b
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328 dst_cnt++;
329 }
330 /* cost matrix sorted by most to least similar pair */
331 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
332 for (i = 0; i < num_create * num_src; i++) {
25d5ea41
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333 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
334 if (dst->pair)
335 continue; /* already done, either exact or fuzzy. */
427dcb4b 336 if (mx[i].score < minimum_score)
15d061b4 337 break; /* there is no more usable pair. */
5098bafb
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338 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
339 rename_count++;
427dcb4b
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340 }
341 free(mx);
427dcb4b 342
15d061b4 343 cleanup:
427dcb4b 344 /* At this point, we have found some renames and copies and they
5098bafb 345 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 346 */
25d5ea41
JH
347 outq.queue = NULL;
348 outq.nr = outq.alloc = 0;
427dcb4b 349 for (i = 0; i < q->nr; i++) {
25d5ea41 350 struct diff_filepair *p = q->queue[i];
25d5ea41
JH
351 struct diff_filepair *pair_to_free = NULL;
352
2cd68882
JH
353 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
354 /*
355 * Creation
356 *
357 * We would output this create record if it has
358 * not been turned into a rename/copy already.
359 */
360 struct diff_rename_dst *dst =
361 locate_rename_dst(p->two, 0);
362 if (dst && dst->pair) {
25d5ea41
JH
363 diff_q(&outq, dst->pair);
364 pair_to_free = p;
365 }
366 else
2cd68882
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367 /* no matching rename/copy source, so
368 * record this as a creation.
25d5ea41
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369 */
370 diff_q(&outq, p);
427dcb4b 371 }
2cd68882
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372 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
373 /*
374 * Deletion
375 *
f345b0a0
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376 * We would output this delete record if:
377 *
378 * (1) this is a broken delete and the counterpart
379 * broken create remains in the output; or
5098bafb
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380 * (2) this is not a broken delete, and rename_dst
381 * does not have a rename/copy to move p->one->path
382 * out of existence.
f345b0a0
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383 *
384 * Otherwise, the counterpart broken create
385 * has been turned into a rename-edit; or
386 * delete did not have a matching create to
387 * begin with.
2cd68882 388 */
f345b0a0
JH
389 if (DIFF_PAIR_BROKEN(p)) {
390 /* broken delete */
391 struct diff_rename_dst *dst =
392 locate_rename_dst(p->one, 0);
393 if (dst && dst->pair)
394 /* counterpart is now rename/copy */
395 pair_to_free = p;
396 }
397 else {
5098bafb
JH
398 for (j = 0; j < rename_dst_nr; j++) {
399 if (!rename_dst[j].pair)
400 continue;
401 if (strcmp(rename_dst[j].pair->
402 one->path,
403 p->one->path))
404 continue;
405 break;
406 }
407 if (j < rename_dst_nr)
f345b0a0
JH
408 /* this path remains */
409 pair_to_free = p;
410 }
2cd68882
JH
411
412 if (pair_to_free)
413 ;
414 else
415 diff_q(&outq, p);
416 }
25d5ea41 417 else if (!diff_unmodified_pair(p))
15d061b4 418 /* all the usual ones need to be kept */
25d5ea41 419 diff_q(&outq, p);
15d061b4
JH
420 else
421 /* no need to keep unmodified pairs */
422 pair_to_free = p;
423
226406f6
JH
424 if (pair_to_free)
425 diff_free_filepair(pair_to_free);
427dcb4b 426 }
25d5ea41 427 diff_debug_queue("done copying original", &outq);
427dcb4b 428
25d5ea41
JH
429 free(q->queue);
430 *q = outq;
431 diff_debug_queue("done collapsing", q);
427dcb4b 432
6bac10d8
JH
433 /* We need to see which rename source really stays here;
434 * earlier we only checked if the path is left in the result,
435 * but even if a path remains in the result, if that is coming
436 * from copying something else on top of it, then the original
437 * source is lost and does not stay.
438 */
439 for (i = 0; i < q->nr; i++) {
440 struct diff_filepair *p = q->queue[i];
441 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
442 /* If one appears as the target of a rename-copy,
443 * then mark p->source_stays = 0; otherwise
444 * leave it as is.
445 */
446 p->source_stays = compute_stays(q, p->one);
447 }
448 }
449
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450 for (i = 0; i < rename_dst_nr; i++) {
451 diff_free_filespec_data(rename_dst[i].two);
452 free(rename_dst[i].two);
453 }
454
25d5ea41
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455 free(rename_dst);
456 rename_dst = NULL;
457 rename_dst_nr = rename_dst_alloc = 0;
458 free(rename_src);
459 rename_src = NULL;
460 rename_src_nr = rename_src_alloc = 0;
427dcb4b
JH
461 return;
462}