1/* 2 * Copyright (C) 2005 Junio C Hamano 3 */ 4#include "cache.h" 5#include "diff.h" 6#include "diffcore.h" 7 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; 15 16static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two, 17 int insert_ok) 18{ 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)); 48 rename_dst[first].two = alloc_filespec(two->path); 49 fill_filespec(rename_dst[first].two, two->sha1, two->mode); 50 rename_dst[first].pair = NULL; 51 return &(rename_dst[first]); 52} 53 54/* Table of rename/copy src files */ 55static struct diff_rename_src { 56 struct diff_filespec *one; 57 unsigned short score; /* to remember the break score */ 58 unsigned src_path_left : 1; 59} *rename_src; 60static int rename_src_nr, rename_src_alloc; 61 62static struct diff_rename_src *register_rename_src(struct diff_filespec *one, 63 int src_path_left, 64 unsigned short score) 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 } 82 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)); 88 } 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; 94 rename_src[first].score = score; 95 rename_src[first].src_path_left = src_path_left; 96 return &(rename_src[first]); 97} 98 99static int is_exact_match(struct diff_filespec *src, 100 struct diff_filespec *dst, 101 int contents_too) 102{ 103 if (src->sha1_valid && dst->sha1_valid && 104 !hashcmp(src->sha1, dst->sha1)) 105 return 1; 106 if (!contents_too) 107 return 0; 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 (src->sha1_valid && dst->sha1_valid) 113 return !hashcmp(src->sha1, dst->sha1); 114 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 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 { 123 int src; /* index in rename_src */ 124 int dst; /* index in rename_dst */ 125 int score; 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 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. 144 */ 145 unsigned long max_size, delta_size, base_size, src_copied, literal_added; 146 unsigned long delta_limit; 147 int score; 148 149 /* 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; 155 156 max_size = ((src->size > dst->size) ? src->size : dst->size); 157 base_size = ((src->size < dst->size) ? src->size : dst->size); 158 delta_size = max_size - base_size; 159 160 /* We would not consider edits that change the file size so 161 * drastically. delta_size must be smaller than 162 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size). 163 * 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. 167 */ 168 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) 169 return 0; 170 171 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 172 return 0; /* error but caught downstream */ 173 174 175 delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE; 176 if (diffcore_count_changes(src->data, src->size, 177 dst->data, dst->size, 178 &src->cnt_data, &dst->cnt_data, 179 delta_limit, 180 &src_copied, &literal_added)) 181 return 0; 182 183 /* How similar are they? 184 * what percentage of material in dst are from source? 185 */ 186 if (!dst->size) 187 score = 0; /* should not happen */ 188 else 189 score = src_copied * MAX_SCORE / max_size; 190 return score; 191} 192 193static void record_rename_pair(int dst_index, int src_index, int score) 194{ 195 struct diff_filespec *one, *two, *src, *dst; 196 struct diff_filepair *dp; 197 198 if (rename_dst[dst_index].pair) 199 die("internal error: dst already matched."); 200 201 src = rename_src[src_index].one; 202 one = alloc_filespec(src->path); 203 fill_filespec(one, src->sha1, src->mode); 204 205 dst = rename_dst[dst_index].two; 206 two = alloc_filespec(dst->path); 207 fill_filespec(two, dst->sha1, dst->mode); 208 209 dp = diff_queue(NULL, one, two); 210 dp->renamed_pair = 1; 211 if (!strcmp(src->path, dst->path)) 212 dp->score = rename_src[src_index].score; 213 else 214 dp->score = score; 215 dp->source_stays = rename_src[src_index].src_path_left; 216 rename_dst[dst_index].pair = dp; 217} 218 219/* 220 * We sort the rename similarity matrix with the score, in descending 221 * order (the most similar first). 222 */ 223static int score_compare(const void *a_, const void *b_) 224{ 225 const struct diff_score *a = a_, *b = b_; 226 return b->score - a->score; 227} 228 229static int compute_stays(struct diff_queue_struct *q, 230 struct diff_filespec *one) 231{ 232 int i; 233 for (i = 0; i < q->nr; i++) { 234 struct diff_filepair *p = q->queue[i]; 235 if (strcmp(one->path, p->two->path)) 236 continue; 237 if (DIFF_PAIR_RENAME(p)) { 238 return 0; /* something else is renamed into this */ 239 } 240 } 241 return 1; 242} 243 244void diffcore_rename(struct diff_options *options) 245{ 246 int detect_rename = options->detect_rename; 247 int minimum_score = options->rename_score; 248 int rename_limit = options->rename_limit; 249 struct diff_queue_struct *q = &diff_queued_diff; 250 struct diff_queue_struct outq; 251 struct diff_score *mx; 252 int i, j, rename_count, contents_too; 253 int num_create, num_src, dst_cnt; 254 255 if (!minimum_score) 256 minimum_score = DEFAULT_RENAME_SCORE; 257 rename_count = 0; 258 259 for (i = 0; i < q->nr; i++) { 260 struct diff_filepair *p = q->queue[i]; 261 if (!DIFF_FILE_VALID(p->one)) { 262 if (!DIFF_FILE_VALID(p->two)) 263 continue; /* unmerged */ 264 else if (options->single_follow && 265 strcmp(options->single_follow, p->two->path)) 266 continue; /* not interested */ 267 else 268 locate_rename_dst(p->two, 1); 269 } 270 else if (!DIFF_FILE_VALID(p->two)) { 271 /* If the source is a broken "delete", and 272 * they did not really want to get broken, 273 * that means the source actually stays. 274 */ 275 int stays = (p->broken_pair && !p->score); 276 register_rename_src(p->one, stays, p->score); 277 } 278 else if (detect_rename == DIFF_DETECT_COPY) 279 register_rename_src(p->one, 1, p->score); 280 } 281 if (rename_dst_nr == 0 || rename_src_nr == 0 || 282 (0 < rename_limit && rename_limit < rename_dst_nr)) 283 goto cleanup; /* nothing to do */ 284 285 /* We really want to cull the candidates list early 286 * with cheap tests in order to avoid doing deltas. 287 * The first round matches up the up-to-date entries, 288 * and then during the second round we try to match 289 * cache-dirty entries as well. 290 */ 291 for (contents_too = 0; contents_too < 2; contents_too++) { 292 for (i = 0; i < rename_dst_nr; i++) { 293 struct diff_filespec *two = rename_dst[i].two; 294 if (rename_dst[i].pair) 295 continue; /* dealt with an earlier round */ 296 for (j = 0; j < rename_src_nr; j++) { 297 struct diff_filespec *one = rename_src[j].one; 298 if (!is_exact_match(one, two, contents_too)) 299 continue; 300 record_rename_pair(i, j, MAX_SCORE); 301 rename_count++; 302 break; /* we are done with this entry */ 303 } 304 } 305 } 306 307 /* Have we run out the created file pool? If so we can avoid 308 * doing the delta matrix altogether. 309 */ 310 if (rename_count == rename_dst_nr) 311 goto cleanup; 312 313 if (minimum_score == MAX_SCORE) 314 goto cleanup; 315 316 num_create = (rename_dst_nr - rename_count); 317 num_src = rename_src_nr; 318 mx = xmalloc(sizeof(*mx) * num_create * num_src); 319 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 320 int base = dst_cnt * num_src; 321 struct diff_filespec *two = rename_dst[i].two; 322 if (rename_dst[i].pair) 323 continue; /* dealt with exact match already. */ 324 for (j = 0; j < rename_src_nr; j++) { 325 struct diff_filespec *one = rename_src[j].one; 326 struct diff_score *m = &mx[base+j]; 327 m->src = j; 328 m->dst = i; 329 m->score = estimate_similarity(one, two, 330 minimum_score); 331 } 332 /* We do not need the text anymore */ 333 diff_free_filespec_data(two); 334 dst_cnt++; 335 } 336 /* cost matrix sorted by most to least similar pair */ 337 qsort(mx, num_create * num_src, sizeof(*mx), score_compare); 338 for (i = 0; i < num_create * num_src; i++) { 339 struct diff_rename_dst *dst = &rename_dst[mx[i].dst]; 340 if (dst->pair) 341 continue; /* already done, either exact or fuzzy. */ 342 if (mx[i].score < minimum_score) 343 break; /* there is no more usable pair. */ 344 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 345 rename_count++; 346 } 347 free(mx); 348 349 cleanup: 350 /* At this point, we have found some renames and copies and they 351 * are recorded in rename_dst. The original list is still in *q. 352 */ 353 outq.queue = NULL; 354 outq.nr = outq.alloc = 0; 355 for (i = 0; i < q->nr; i++) { 356 struct diff_filepair *p = q->queue[i]; 357 struct diff_filepair *pair_to_free = NULL; 358 359 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 360 /* 361 * Creation 362 * 363 * We would output this create record if it has 364 * not been turned into a rename/copy already. 365 */ 366 struct diff_rename_dst *dst = 367 locate_rename_dst(p->two, 0); 368 if (dst && dst->pair) { 369 diff_q(&outq, dst->pair); 370 pair_to_free = p; 371 } 372 else 373 /* no matching rename/copy source, so 374 * record this as a creation. 375 */ 376 diff_q(&outq, p); 377 } 378 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 379 /* 380 * Deletion 381 * 382 * We would output this delete record if: 383 * 384 * (1) this is a broken delete and the counterpart 385 * broken create remains in the output; or 386 * (2) this is not a broken delete, and rename_dst 387 * does not have a rename/copy to move p->one->path 388 * out of existence. 389 * 390 * Otherwise, the counterpart broken create 391 * has been turned into a rename-edit; or 392 * delete did not have a matching create to 393 * begin with. 394 */ 395 if (DIFF_PAIR_BROKEN(p)) { 396 /* broken delete */ 397 struct diff_rename_dst *dst = 398 locate_rename_dst(p->one, 0); 399 if (dst && dst->pair) 400 /* counterpart is now rename/copy */ 401 pair_to_free = p; 402 } 403 else { 404 for (j = 0; j < rename_dst_nr; j++) { 405 if (!rename_dst[j].pair) 406 continue; 407 if (strcmp(rename_dst[j].pair-> 408 one->path, 409 p->one->path)) 410 continue; 411 break; 412 } 413 if (j < rename_dst_nr) 414 /* this path remains */ 415 pair_to_free = p; 416 } 417 418 if (pair_to_free) 419 ; 420 else 421 diff_q(&outq, p); 422 } 423 else if (!diff_unmodified_pair(p)) 424 /* all the usual ones need to be kept */ 425 diff_q(&outq, p); 426 else 427 /* no need to keep unmodified pairs */ 428 pair_to_free = p; 429 430 if (pair_to_free) 431 diff_free_filepair(pair_to_free); 432 } 433 diff_debug_queue("done copying original", &outq); 434 435 free(q->queue); 436 *q = outq; 437 diff_debug_queue("done collapsing", q); 438 439 /* We need to see which rename source really stays here; 440 * earlier we only checked if the path is left in the result, 441 * but even if a path remains in the result, if that is coming 442 * from copying something else on top of it, then the original 443 * source is lost and does not stay. 444 */ 445 for (i = 0; i < q->nr; i++) { 446 struct diff_filepair *p = q->queue[i]; 447 if (DIFF_PAIR_RENAME(p) && p->source_stays) { 448 /* If one appears as the target of a rename-copy, 449 * then mark p->source_stays = 0; otherwise 450 * leave it as is. 451 */ 452 p->source_stays = compute_stays(q, p->one); 453 } 454 } 455 456 for (i = 0; i < rename_dst_nr; i++) { 457 diff_free_filespec_data(rename_dst[i].two); 458 free(rename_dst[i].two); 459 } 460 461 free(rename_dst); 462 rename_dst = NULL; 463 rename_dst_nr = rename_dst_alloc = 0; 464 free(rename_src); 465 rename_src = NULL; 466 rename_src_nr = rename_src_alloc = 0; 467 return; 468}