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[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
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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;
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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,
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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;
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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;
7da41f48
SP
112 if (src->sha1_valid && dst->sha1_valid)
113 return !hashcmp(src->sha1, dst->sha1);
f0c6b2a2 114 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
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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
122struct diff_score {
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123 int src; /* index in rename_src */
124 int dst; /* index in rename_dst */
427dcb4b 125 int score;
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126};
127
128static int estimate_similarity(struct diff_filespec *src,
129 struct diff_filespec *dst,
130 int minimum_score)
131{
132 /* src points at a file that existed in the original tree (or
133 * optionally a file in the destination tree) and dst points
134 * at a newly created file. They may be quite similar, in which
135 * case we want to say src is renamed to dst or src is copied into
136 * dst, and then some edit has been applied to dst.
137 *
138 * Compare them and return how similar they are, representing
f0c6b2a2
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139 * the score as an integer between 0 and MAX_SCORE.
140 *
141 * When there is an exact match, it is considered a better
142 * match than anything else; the destination does not even
143 * call into this function in that case.
427dcb4b 144 */
90bd932c 145 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
75c660ac 146 unsigned long delta_limit;
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147 int score;
148
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149 /* We deal only with regular files. Symlink renames are handled
150 * only when they are exact matches --- in other words, no edits
151 * after renaming.
152 */
153 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
154 return 0;
155
90bd932c 156 max_size = ((src->size > dst->size) ? src->size : dst->size);
58b103f5 157 base_size = ((src->size < dst->size) ? src->size : dst->size);
90bd932c 158 delta_size = max_size - base_size;
427dcb4b 159
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160 /* We would not consider edits that change the file size so
161 * drastically. delta_size must be smaller than
cd1870ed 162 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
f0c6b2a2 163 *
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164 * Note that base_size == 0 case is handled here already
165 * and the final score computation below would not have a
166 * divide-by-zero issue.
427dcb4b 167 */
cd1870ed 168 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
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169 return 0;
170
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171 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
172 return 0; /* error but caught downstream */
173
85976974 174
dc49cd76
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175 delta_limit = (unsigned long)
176 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
65416758
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177 if (diffcore_count_changes(src->data, src->size,
178 dst->data, dst->size,
c06c7966 179 &src->cnt_data, &dst->cnt_data,
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180 delta_limit,
181 &src_copied, &literal_added))
85976974 182 return 0;
355e76a4 183
1706306a
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184 /* How similar are they?
185 * what percentage of material in dst are from source?
427dcb4b 186 */
90bd932c 187 if (!dst->size)
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188 score = 0; /* should not happen */
189 else
dc49cd76 190 score = (int)(src_copied * MAX_SCORE / max_size);
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191 return score;
192}
193
5098bafb 194static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 195{
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196 struct diff_filespec *one, *two, *src, *dst;
197 struct diff_filepair *dp;
f7c1512a 198
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199 if (rename_dst[dst_index].pair)
200 die("internal error: dst already matched.");
427dcb4b 201
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202 src = rename_src[src_index].one;
203 one = alloc_filespec(src->path);
204 fill_filespec(one, src->sha1, src->mode);
427dcb4b 205
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206 dst = rename_dst[dst_index].two;
207 two = alloc_filespec(dst->path);
208 fill_filespec(two, dst->sha1, dst->mode);
427dcb4b 209
5098bafb 210 dp = diff_queue(NULL, one, two);
ef677686 211 dp->renamed_pair = 1;
fc580719
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212 if (!strcmp(src->path, dst->path))
213 dp->score = rename_src[src_index].score;
214 else
215 dp->score = score;
6bac10d8 216 dp->source_stays = rename_src[src_index].src_path_left;
25d5ea41 217 rename_dst[dst_index].pair = dp;
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218}
219
220/*
221 * We sort the rename similarity matrix with the score, in descending
15d061b4 222 * order (the most similar first).
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223 */
224static int score_compare(const void *a_, const void *b_)
225{
226 const struct diff_score *a = a_, *b = b_;
227 return b->score - a->score;
228}
229
6bac10d8
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230static int compute_stays(struct diff_queue_struct *q,
231 struct diff_filespec *one)
232{
233 int i;
234 for (i = 0; i < q->nr; i++) {
235 struct diff_filepair *p = q->queue[i];
236 if (strcmp(one->path, p->two->path))
237 continue;
238 if (DIFF_PAIR_RENAME(p)) {
239 return 0; /* something else is renamed into this */
240 }
241 }
242 return 1;
243}
244
8082d8d3 245void diffcore_rename(struct diff_options *options)
427dcb4b 246{
8082d8d3
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247 int detect_rename = options->detect_rename;
248 int minimum_score = options->rename_score;
249 int rename_limit = options->rename_limit;
38c6f780 250 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 251 struct diff_queue_struct outq;
427dcb4b 252 struct diff_score *mx;
17e6019a 253 int i, j, rename_count, contents_too;
25d5ea41 254 int num_create, num_src, dst_cnt;
427dcb4b 255
26dee0ad 256 if (!minimum_score)
f345b0a0 257 minimum_score = DEFAULT_RENAME_SCORE;
5098bafb 258 rename_count = 0;
427dcb4b 259
427dcb4b 260 for (i = 0; i < q->nr; i++) {
52e95789 261 struct diff_filepair *p = q->queue[i];
2f3f8b21 262 if (!DIFF_FILE_VALID(p->one)) {
81e50eab 263 if (!DIFF_FILE_VALID(p->two))
60896c7b 264 continue; /* unmerged */
2f3f8b21
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265 else if (options->single_follow &&
266 strcmp(options->single_follow, p->two->path))
267 continue; /* not interested */
427dcb4b 268 else
25d5ea41 269 locate_rename_dst(p->two, 1);
2f3f8b21 270 }
2210100a
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271 else if (!DIFF_FILE_VALID(p->two)) {
272 /* If the source is a broken "delete", and
273 * they did not really want to get broken,
274 * that means the source actually stays.
275 */
276 int stays = (p->broken_pair && !p->score);
fc580719 277 register_rename_src(p->one, stays, p->score);
2210100a 278 }
15d061b4 279 else if (detect_rename == DIFF_DETECT_COPY)
fc580719 280 register_rename_src(p->one, 1, p->score);
427dcb4b 281 }
7d6fb370 282 if (rename_dst_nr == 0 || rename_src_nr == 0 ||
3299c6f6 283 (0 < rename_limit && rename_limit < rename_dst_nr))
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284 goto cleanup; /* nothing to do */
285
286 /* We really want to cull the candidates list early
287 * with cheap tests in order to avoid doing deltas.
17e6019a
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288 * The first round matches up the up-to-date entries,
289 * and then during the second round we try to match
290 * cache-dirty entries as well.
427dcb4b 291 */
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292 for (contents_too = 0; contents_too < 2; contents_too++) {
293 for (i = 0; i < rename_dst_nr; i++) {
294 struct diff_filespec *two = rename_dst[i].two;
295 if (rename_dst[i].pair)
296 continue; /* dealt with an earlier round */
297 for (j = 0; j < rename_src_nr; j++) {
298 struct diff_filespec *one = rename_src[j].one;
299 if (!is_exact_match(one, two, contents_too))
300 continue;
dc49cd76 301 record_rename_pair(i, j, (int)MAX_SCORE);
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302 rename_count++;
303 break; /* we are done with this entry */
304 }
427dcb4b
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305 }
306 }
427dcb4b
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307
308 /* Have we run out the created file pool? If so we can avoid
309 * doing the delta matrix altogether.
310 */
5098bafb 311 if (rename_count == rename_dst_nr)
15d061b4 312 goto cleanup;
427dcb4b 313
9f70b806
JH
314 if (minimum_score == MAX_SCORE)
315 goto cleanup;
316
5098bafb 317 num_create = (rename_dst_nr - rename_count);
25d5ea41 318 num_src = rename_src_nr;
427dcb4b 319 mx = xmalloc(sizeof(*mx) * num_create * num_src);
25d5ea41 320 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
427dcb4b 321 int base = dst_cnt * num_src;
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322 struct diff_filespec *two = rename_dst[i].two;
323 if (rename_dst[i].pair)
427dcb4b 324 continue; /* dealt with exact match already. */
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325 for (j = 0; j < rename_src_nr; j++) {
326 struct diff_filespec *one = rename_src[j].one;
327 struct diff_score *m = &mx[base+j];
328 m->src = j;
329 m->dst = i;
330 m->score = estimate_similarity(one, two,
331 minimum_score);
50b2b538 332 diff_free_filespec_data(one);
427dcb4b 333 }
2821104d
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334 /* We do not need the text anymore */
335 diff_free_filespec_data(two);
427dcb4b
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336 dst_cnt++;
337 }
338 /* cost matrix sorted by most to least similar pair */
339 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
340 for (i = 0; i < num_create * num_src; i++) {
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341 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
342 if (dst->pair)
343 continue; /* already done, either exact or fuzzy. */
427dcb4b 344 if (mx[i].score < minimum_score)
15d061b4 345 break; /* there is no more usable pair. */
5098bafb
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346 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
347 rename_count++;
427dcb4b
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348 }
349 free(mx);
427dcb4b 350
15d061b4 351 cleanup:
427dcb4b 352 /* At this point, we have found some renames and copies and they
5098bafb 353 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 354 */
25d5ea41
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355 outq.queue = NULL;
356 outq.nr = outq.alloc = 0;
427dcb4b 357 for (i = 0; i < q->nr; i++) {
25d5ea41 358 struct diff_filepair *p = q->queue[i];
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359 struct diff_filepair *pair_to_free = NULL;
360
2cd68882
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361 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
362 /*
363 * Creation
364 *
365 * We would output this create record if it has
366 * not been turned into a rename/copy already.
367 */
368 struct diff_rename_dst *dst =
369 locate_rename_dst(p->two, 0);
370 if (dst && dst->pair) {
25d5ea41
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371 diff_q(&outq, dst->pair);
372 pair_to_free = p;
373 }
374 else
2cd68882
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375 /* no matching rename/copy source, so
376 * record this as a creation.
25d5ea41
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377 */
378 diff_q(&outq, p);
427dcb4b 379 }
2cd68882
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380 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
381 /*
382 * Deletion
383 *
f345b0a0
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384 * We would output this delete record if:
385 *
386 * (1) this is a broken delete and the counterpart
387 * broken create remains in the output; or
5098bafb
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388 * (2) this is not a broken delete, and rename_dst
389 * does not have a rename/copy to move p->one->path
390 * out of existence.
f345b0a0
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391 *
392 * Otherwise, the counterpart broken create
393 * has been turned into a rename-edit; or
394 * delete did not have a matching create to
395 * begin with.
2cd68882 396 */
f345b0a0
JH
397 if (DIFF_PAIR_BROKEN(p)) {
398 /* broken delete */
399 struct diff_rename_dst *dst =
400 locate_rename_dst(p->one, 0);
401 if (dst && dst->pair)
402 /* counterpart is now rename/copy */
403 pair_to_free = p;
404 }
405 else {
5098bafb
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406 for (j = 0; j < rename_dst_nr; j++) {
407 if (!rename_dst[j].pair)
408 continue;
409 if (strcmp(rename_dst[j].pair->
410 one->path,
411 p->one->path))
412 continue;
413 break;
414 }
415 if (j < rename_dst_nr)
f345b0a0
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416 /* this path remains */
417 pair_to_free = p;
418 }
2cd68882
JH
419
420 if (pair_to_free)
421 ;
422 else
423 diff_q(&outq, p);
424 }
25d5ea41 425 else if (!diff_unmodified_pair(p))
15d061b4 426 /* all the usual ones need to be kept */
25d5ea41 427 diff_q(&outq, p);
15d061b4
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428 else
429 /* no need to keep unmodified pairs */
430 pair_to_free = p;
431
226406f6
JH
432 if (pair_to_free)
433 diff_free_filepair(pair_to_free);
427dcb4b 434 }
25d5ea41 435 diff_debug_queue("done copying original", &outq);
427dcb4b 436
25d5ea41
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437 free(q->queue);
438 *q = outq;
439 diff_debug_queue("done collapsing", q);
427dcb4b 440
6bac10d8
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441 /* We need to see which rename source really stays here;
442 * earlier we only checked if the path is left in the result,
443 * but even if a path remains in the result, if that is coming
444 * from copying something else on top of it, then the original
445 * source is lost and does not stay.
446 */
447 for (i = 0; i < q->nr; i++) {
448 struct diff_filepair *p = q->queue[i];
449 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
450 /* If one appears as the target of a rename-copy,
451 * then mark p->source_stays = 0; otherwise
452 * leave it as is.
453 */
454 p->source_stays = compute_stays(q, p->one);
455 }
456 }
457
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458 for (i = 0; i < rename_dst_nr; i++) {
459 diff_free_filespec_data(rename_dst[i].two);
460 free(rename_dst[i].two);
461 }
462
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463 free(rename_dst);
464 rename_dst = NULL;
465 rename_dst_nr = rename_dst_alloc = 0;
466 free(rename_src);
467 rename_src = NULL;
468 rename_src_nr = rename_src_alloc = 0;
427dcb4b
JH
469 return;
470}