diff: fix output of total-rewrite diff.
[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
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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]);
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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;
6bac10d8 57 unsigned src_path_left : 1;
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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)
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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
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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 }
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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]);
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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;
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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))
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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 {
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114 int src; /* index in rename_src */
115 int dst; /* index in rename_dst */
427dcb4b 116 int score;
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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
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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 */
90bd932c 136 unsigned long max_size, delta_size, base_size, src_copied, literal_added;
75c660ac 137 unsigned long delta_limit;
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138 int score;
139
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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
90bd932c 147 max_size = ((src->size > dst->size) ? src->size : dst->size);
58b103f5 148 base_size = ((src->size < dst->size) ? src->size : dst->size);
90bd932c 149 delta_size = max_size - base_size;
427dcb4b 150
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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 *
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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)
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160 return 0;
161
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162 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
163 return 0; /* error but caught downstream */
164
85976974 165
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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,
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170 delta_limit,
171 &src_copied, &literal_added))
85976974 172 return 0;
355e76a4 173
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174 /* How similar are they?
175 * what percentage of material in dst are from source?
427dcb4b 176 */
90bd932c 177 if (!dst->size)
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178 score = 0; /* should not happen */
179 else
90bd932c 180 score = src_copied * MAX_SCORE / max_size;
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181 return score;
182}
183
5098bafb 184static void record_rename_pair(int dst_index, int src_index, int score)
427dcb4b 185{
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186 struct diff_filespec *one, *two, *src, *dst;
187 struct diff_filepair *dp;
f7c1512a 188
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189 if (rename_dst[dst_index].pair)
190 die("internal error: dst already matched.");
427dcb4b 191
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192 src = rename_src[src_index].one;
193 one = alloc_filespec(src->path);
194 fill_filespec(one, src->sha1, src->mode);
427dcb4b 195
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196 dst = rename_dst[dst_index].two;
197 two = alloc_filespec(dst->path);
198 fill_filespec(two, dst->sha1, dst->mode);
427dcb4b 199
5098bafb 200 dp = diff_queue(NULL, one, two);
01c4e70f 201 dp->score = score;
6bac10d8 202 dp->source_stays = rename_src[src_index].src_path_left;
25d5ea41 203 rename_dst[dst_index].pair = dp;
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204}
205
206/*
207 * We sort the rename similarity matrix with the score, in descending
15d061b4 208 * order (the most similar first).
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209 */
210static int score_compare(const void *a_, const void *b_)
211{
212 const struct diff_score *a = a_, *b = b_;
213 return b->score - a->score;
214}
215
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216static int compute_stays(struct diff_queue_struct *q,
217 struct diff_filespec *one)
218{
219 int i;
220 for (i = 0; i < q->nr; i++) {
221 struct diff_filepair *p = q->queue[i];
222 if (strcmp(one->path, p->two->path))
223 continue;
224 if (DIFF_PAIR_RENAME(p)) {
225 return 0; /* something else is renamed into this */
226 }
227 }
228 return 1;
229}
230
8082d8d3 231void diffcore_rename(struct diff_options *options)
427dcb4b 232{
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233 int detect_rename = options->detect_rename;
234 int minimum_score = options->rename_score;
235 int rename_limit = options->rename_limit;
38c6f780 236 struct diff_queue_struct *q = &diff_queued_diff;
5098bafb 237 struct diff_queue_struct outq;
427dcb4b 238 struct diff_score *mx;
5098bafb 239 int i, j, rename_count;
25d5ea41 240 int num_create, num_src, dst_cnt;
427dcb4b 241
26dee0ad 242 if (!minimum_score)
f345b0a0 243 minimum_score = DEFAULT_RENAME_SCORE;
5098bafb 244 rename_count = 0;
427dcb4b 245
427dcb4b 246 for (i = 0; i < q->nr; i++) {
52e95789 247 struct diff_filepair *p = q->queue[i];
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248 if (!DIFF_FILE_VALID(p->one))
249 if (!DIFF_FILE_VALID(p->two))
60896c7b 250 continue; /* unmerged */
427dcb4b 251 else
25d5ea41 252 locate_rename_dst(p->two, 1);
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253 else if (!DIFF_FILE_VALID(p->two)) {
254 /* If the source is a broken "delete", and
255 * they did not really want to get broken,
256 * that means the source actually stays.
257 */
258 int stays = (p->broken_pair && !p->score);
259 register_rename_src(p->one, stays);
260 }
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261 else if (detect_rename == DIFF_DETECT_COPY)
262 register_rename_src(p->one, 1);
427dcb4b 263 }
7d6fb370 264 if (rename_dst_nr == 0 || rename_src_nr == 0 ||
3299c6f6 265 (0 < rename_limit && rename_limit < rename_dst_nr))
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266 goto cleanup; /* nothing to do */
267
268 /* We really want to cull the candidates list early
269 * with cheap tests in order to avoid doing deltas.
427dcb4b 270 */
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271 for (i = 0; i < rename_dst_nr; i++) {
272 struct diff_filespec *two = rename_dst[i].two;
273 for (j = 0; j < rename_src_nr; j++) {
274 struct diff_filespec *one = rename_src[j].one;
275 if (!is_exact_match(one, two))
276 continue;
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277 record_rename_pair(i, j, MAX_SCORE);
278 rename_count++;
25d5ea41 279 break; /* we are done with this entry */
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280 }
281 }
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282
283 /* Have we run out the created file pool? If so we can avoid
284 * doing the delta matrix altogether.
285 */
5098bafb 286 if (rename_count == rename_dst_nr)
15d061b4 287 goto cleanup;
427dcb4b 288
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289 if (minimum_score == MAX_SCORE)
290 goto cleanup;
291
5098bafb 292 num_create = (rename_dst_nr - rename_count);
25d5ea41 293 num_src = rename_src_nr;
427dcb4b 294 mx = xmalloc(sizeof(*mx) * num_create * num_src);
25d5ea41 295 for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
427dcb4b 296 int base = dst_cnt * num_src;
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297 struct diff_filespec *two = rename_dst[i].two;
298 if (rename_dst[i].pair)
427dcb4b 299 continue; /* dealt with exact match already. */
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300 for (j = 0; j < rename_src_nr; j++) {
301 struct diff_filespec *one = rename_src[j].one;
302 struct diff_score *m = &mx[base+j];
303 m->src = j;
304 m->dst = i;
305 m->score = estimate_similarity(one, two,
306 minimum_score);
427dcb4b 307 }
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308 /* We do not need the text anymore */
309 diff_free_filespec_data(two);
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310 dst_cnt++;
311 }
312 /* cost matrix sorted by most to least similar pair */
313 qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
314 for (i = 0; i < num_create * num_src; i++) {
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315 struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
316 if (dst->pair)
317 continue; /* already done, either exact or fuzzy. */
427dcb4b 318 if (mx[i].score < minimum_score)
15d061b4 319 break; /* there is no more usable pair. */
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320 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
321 rename_count++;
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322 }
323 free(mx);
427dcb4b 324
15d061b4 325 cleanup:
427dcb4b 326 /* At this point, we have found some renames and copies and they
5098bafb 327 * are recorded in rename_dst. The original list is still in *q.
427dcb4b 328 */
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329 outq.queue = NULL;
330 outq.nr = outq.alloc = 0;
427dcb4b 331 for (i = 0; i < q->nr; i++) {
25d5ea41 332 struct diff_filepair *p = q->queue[i];
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333 struct diff_filepair *pair_to_free = NULL;
334
2cd68882
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335 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
336 /*
337 * Creation
338 *
339 * We would output this create record if it has
340 * not been turned into a rename/copy already.
341 */
342 struct diff_rename_dst *dst =
343 locate_rename_dst(p->two, 0);
344 if (dst && dst->pair) {
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345 diff_q(&outq, dst->pair);
346 pair_to_free = p;
347 }
348 else
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349 /* no matching rename/copy source, so
350 * record this as a creation.
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351 */
352 diff_q(&outq, p);
427dcb4b 353 }
2cd68882
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354 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
355 /*
356 * Deletion
357 *
f345b0a0
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358 * We would output this delete record if:
359 *
360 * (1) this is a broken delete and the counterpart
361 * broken create remains in the output; or
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362 * (2) this is not a broken delete, and rename_dst
363 * does not have a rename/copy to move p->one->path
364 * out of existence.
f345b0a0
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365 *
366 * Otherwise, the counterpart broken create
367 * has been turned into a rename-edit; or
368 * delete did not have a matching create to
369 * begin with.
2cd68882 370 */
f345b0a0
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371 if (DIFF_PAIR_BROKEN(p)) {
372 /* broken delete */
373 struct diff_rename_dst *dst =
374 locate_rename_dst(p->one, 0);
375 if (dst && dst->pair)
376 /* counterpart is now rename/copy */
377 pair_to_free = p;
378 }
379 else {
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380 for (j = 0; j < rename_dst_nr; j++) {
381 if (!rename_dst[j].pair)
382 continue;
383 if (strcmp(rename_dst[j].pair->
384 one->path,
385 p->one->path))
386 continue;
387 break;
388 }
389 if (j < rename_dst_nr)
f345b0a0
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390 /* this path remains */
391 pair_to_free = p;
392 }
2cd68882
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393
394 if (pair_to_free)
395 ;
396 else
397 diff_q(&outq, p);
398 }
25d5ea41 399 else if (!diff_unmodified_pair(p))
15d061b4 400 /* all the usual ones need to be kept */
25d5ea41 401 diff_q(&outq, p);
15d061b4
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402 else
403 /* no need to keep unmodified pairs */
404 pair_to_free = p;
405
226406f6
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406 if (pair_to_free)
407 diff_free_filepair(pair_to_free);
427dcb4b 408 }
25d5ea41 409 diff_debug_queue("done copying original", &outq);
427dcb4b 410
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411 free(q->queue);
412 *q = outq;
413 diff_debug_queue("done collapsing", q);
427dcb4b 414
6bac10d8
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415 /* We need to see which rename source really stays here;
416 * earlier we only checked if the path is left in the result,
417 * but even if a path remains in the result, if that is coming
418 * from copying something else on top of it, then the original
419 * source is lost and does not stay.
420 */
421 for (i = 0; i < q->nr; i++) {
422 struct diff_filepair *p = q->queue[i];
423 if (DIFF_PAIR_RENAME(p) && p->source_stays) {
424 /* If one appears as the target of a rename-copy,
425 * then mark p->source_stays = 0; otherwise
426 * leave it as is.
427 */
428 p->source_stays = compute_stays(q, p->one);
429 }
430 }
431
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432 for (i = 0; i < rename_dst_nr; i++) {
433 diff_free_filespec_data(rename_dst[i].two);
434 free(rename_dst[i].two);
435 }
436
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437 free(rename_dst);
438 rename_dst = NULL;
439 rename_dst_nr = rename_dst_alloc = 0;
440 free(rename_src);
441 rename_src = NULL;
442 rename_src_nr = rename_src_alloc = 0;
427dcb4b
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443 return;
444}