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 122static int basename_same(struct diff_filespec *src, struct diff_filespec *dst) 123{ 124 int src_len = strlen(src->path), dst_len = strlen(dst->path); 125 while (src_len && dst_len) { 126 char c1 = src->path[--src_len]; 127 char c2 = dst->path[--dst_len]; 128 if (c1 != c2) 129 return 0; 130 if (c1 == '/') 131 return 1; 132 } 133 return (!src_len || src->path[src_len - 1] == '/') && 134 (!dst_len || dst->path[dst_len - 1] == '/'); 135} 136 137struct diff_score { 138 int src; /* index in rename_src */ 139 int dst; /* index in rename_dst */ 140 int score; 141}; 142 143static int estimate_similarity(struct diff_filespec *src, 144 struct diff_filespec *dst, 145 int minimum_score) 146{ 147 /* src points at a file that existed in the original tree (or 148 * optionally a file in the destination tree) and dst points 149 * at a newly created file. They may be quite similar, in which 150 * case we want to say src is renamed to dst or src is copied into 151 * dst, and then some edit has been applied to dst. 152 * 153 * Compare them and return how similar they are, representing 154 * the score as an integer between 0 and MAX_SCORE. 155 * 156 * When there is an exact match, it is considered a better 157 * match than anything else; the destination does not even 158 * call into this function in that case. 159 */ 160 unsigned long max_size, delta_size, base_size, src_copied, literal_added; 161 unsigned long delta_limit; 162 int score; 163 164 /* We deal only with regular files. Symlink renames are handled 165 * only when they are exact matches --- in other words, no edits 166 * after renaming. 167 */ 168 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode)) 169 return 0; 170 171 max_size = ((src->size > dst->size) ? src->size : dst->size); 172 base_size = ((src->size < dst->size) ? src->size : dst->size); 173 delta_size = max_size - base_size; 174 175 /* We would not consider edits that change the file size so 176 * drastically. delta_size must be smaller than 177 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size). 178 * 179 * Note that base_size == 0 case is handled here already 180 * and the final score computation below would not have a 181 * divide-by-zero issue. 182 */ 183 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) 184 return 0; 185 186 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 187 return 0; /* error but caught downstream */ 188 189 190 delta_limit = (unsigned long) 191 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE); 192 if (diffcore_count_changes(src->data, src->size, 193 dst->data, dst->size, 194 &src->cnt_data, &dst->cnt_data, 195 delta_limit, 196 &src_copied, &literal_added)) 197 return 0; 198 199 /* How similar are they? 200 * what percentage of material in dst are from source? 201 */ 202 if (!dst->size) 203 score = 0; /* should not happen */ 204 else { 205 score = (int)(src_copied * MAX_SCORE / max_size); 206 if (basename_same(src, dst)) 207 score++; 208 } 209 return score; 210} 211 212static void record_rename_pair(int dst_index, int src_index, int score) 213{ 214 struct diff_filespec *one, *two, *src, *dst; 215 struct diff_filepair *dp; 216 217 if (rename_dst[dst_index].pair) 218 die("internal error: dst already matched."); 219 220 src = rename_src[src_index].one; 221 one = alloc_filespec(src->path); 222 fill_filespec(one, src->sha1, src->mode); 223 224 dst = rename_dst[dst_index].two; 225 two = alloc_filespec(dst->path); 226 fill_filespec(two, dst->sha1, dst->mode); 227 228 dp = diff_queue(NULL, one, two); 229 dp->renamed_pair = 1; 230 if (!strcmp(src->path, dst->path)) 231 dp->score = rename_src[src_index].score; 232 else 233 dp->score = score; 234 dp->source_stays = rename_src[src_index].src_path_left; 235 rename_dst[dst_index].pair = dp; 236} 237 238/* 239 * We sort the rename similarity matrix with the score, in descending 240 * order (the most similar first). 241 */ 242static int score_compare(const void *a_, const void *b_) 243{ 244 const struct diff_score *a = a_, *b = b_; 245 return b->score - a->score; 246} 247 248static int compute_stays(struct diff_queue_struct *q, 249 struct diff_filespec *one) 250{ 251 int i; 252 for (i = 0; i < q->nr; i++) { 253 struct diff_filepair *p = q->queue[i]; 254 if (strcmp(one->path, p->two->path)) 255 continue; 256 if (DIFF_PAIR_RENAME(p)) { 257 return 0; /* something else is renamed into this */ 258 } 259 } 260 return 1; 261} 262 263void diffcore_rename(struct diff_options *options) 264{ 265 int detect_rename = options->detect_rename; 266 int minimum_score = options->rename_score; 267 int rename_limit = options->rename_limit; 268 struct diff_queue_struct *q = &diff_queued_diff; 269 struct diff_queue_struct outq; 270 struct diff_score *mx; 271 int i, j, rename_count, contents_too; 272 int num_create, num_src, dst_cnt; 273 274 if (!minimum_score) 275 minimum_score = DEFAULT_RENAME_SCORE; 276 rename_count = 0; 277 278 for (i = 0; i < q->nr; i++) { 279 struct diff_filepair *p = q->queue[i]; 280 if (!DIFF_FILE_VALID(p->one)) { 281 if (!DIFF_FILE_VALID(p->two)) 282 continue; /* unmerged */ 283 else if (options->single_follow && 284 strcmp(options->single_follow, p->two->path)) 285 continue; /* not interested */ 286 else 287 locate_rename_dst(p->two, 1); 288 } 289 else if (!DIFF_FILE_VALID(p->two)) { 290 /* If the source is a broken "delete", and 291 * they did not really want to get broken, 292 * that means the source actually stays. 293 */ 294 int stays = (p->broken_pair && !p->score); 295 register_rename_src(p->one, stays, p->score); 296 } 297 else if (detect_rename == DIFF_DETECT_COPY) 298 register_rename_src(p->one, 1, p->score); 299 } 300 if (rename_dst_nr == 0 || rename_src_nr == 0 || 301 (0 < rename_limit && rename_limit < rename_dst_nr)) 302 goto cleanup; /* nothing to do */ 303 304 /* We really want to cull the candidates list early 305 * with cheap tests in order to avoid doing deltas. 306 * The first round matches up the up-to-date entries, 307 * and then during the second round we try to match 308 * cache-dirty entries as well. 309 */ 310 for (contents_too = 0; contents_too < 2; contents_too++) { 311 for (i = 0; i < rename_dst_nr; i++) { 312 struct diff_filespec *two = rename_dst[i].two; 313 if (rename_dst[i].pair) 314 continue; /* dealt with an earlier round */ 315 for (j = 0; j < rename_src_nr; j++) { 316 int k; 317 struct diff_filespec *one = rename_src[j].one; 318 if (!is_exact_match(one, two, contents_too)) 319 continue; 320 321 /* see if there is a basename match, too */ 322 for (k = j; k < rename_src_nr; k++) { 323 one = rename_src[k].one; 324 if (basename_same(one, two) && 325 is_exact_match(one, two, 326 contents_too)) { 327 j = k; 328 break; 329 } 330 } 331 332 record_rename_pair(i, j, (int)MAX_SCORE); 333 rename_count++; 334 break; /* we are done with this entry */ 335 } 336 } 337 } 338 339 /* Have we run out the created file pool? If so we can avoid 340 * doing the delta matrix altogether. 341 */ 342 if (rename_count == rename_dst_nr) 343 goto cleanup; 344 345 if (minimum_score == MAX_SCORE) 346 goto cleanup; 347 348 num_create = (rename_dst_nr - rename_count); 349 num_src = rename_src_nr; 350 mx = xmalloc(sizeof(*mx) * num_create * num_src); 351 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 352 int base = dst_cnt * num_src; 353 struct diff_filespec *two = rename_dst[i].two; 354 if (rename_dst[i].pair) 355 continue; /* dealt with exact match already. */ 356 for (j = 0; j < rename_src_nr; j++) { 357 struct diff_filespec *one = rename_src[j].one; 358 struct diff_score *m = &mx[base+j]; 359 m->src = j; 360 m->dst = i; 361 m->score = estimate_similarity(one, two, 362 minimum_score); 363 diff_free_filespec_data(one); 364 } 365 /* We do not need the text anymore */ 366 diff_free_filespec_data(two); 367 dst_cnt++; 368 } 369 /* cost matrix sorted by most to least similar pair */ 370 qsort(mx, num_create * num_src, sizeof(*mx), score_compare); 371 for (i = 0; i < num_create * num_src; i++) { 372 struct diff_rename_dst *dst = &rename_dst[mx[i].dst]; 373 if (dst->pair) 374 continue; /* already done, either exact or fuzzy. */ 375 if (mx[i].score < minimum_score) 376 break; /* there is no more usable pair. */ 377 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 378 rename_count++; 379 } 380 free(mx); 381 382 cleanup: 383 /* At this point, we have found some renames and copies and they 384 * are recorded in rename_dst. The original list is still in *q. 385 */ 386 outq.queue = NULL; 387 outq.nr = outq.alloc = 0; 388 for (i = 0; i < q->nr; i++) { 389 struct diff_filepair *p = q->queue[i]; 390 struct diff_filepair *pair_to_free = NULL; 391 392 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 393 /* 394 * Creation 395 * 396 * We would output this create record if it has 397 * not been turned into a rename/copy already. 398 */ 399 struct diff_rename_dst *dst = 400 locate_rename_dst(p->two, 0); 401 if (dst && dst->pair) { 402 diff_q(&outq, dst->pair); 403 pair_to_free = p; 404 } 405 else 406 /* no matching rename/copy source, so 407 * record this as a creation. 408 */ 409 diff_q(&outq, p); 410 } 411 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 412 /* 413 * Deletion 414 * 415 * We would output this delete record if: 416 * 417 * (1) this is a broken delete and the counterpart 418 * broken create remains in the output; or 419 * (2) this is not a broken delete, and rename_dst 420 * does not have a rename/copy to move p->one->path 421 * out of existence. 422 * 423 * Otherwise, the counterpart broken create 424 * has been turned into a rename-edit; or 425 * delete did not have a matching create to 426 * begin with. 427 */ 428 if (DIFF_PAIR_BROKEN(p)) { 429 /* broken delete */ 430 struct diff_rename_dst *dst = 431 locate_rename_dst(p->one, 0); 432 if (dst && dst->pair) 433 /* counterpart is now rename/copy */ 434 pair_to_free = p; 435 } 436 else { 437 for (j = 0; j < rename_dst_nr; j++) { 438 if (!rename_dst[j].pair) 439 continue; 440 if (strcmp(rename_dst[j].pair-> 441 one->path, 442 p->one->path)) 443 continue; 444 break; 445 } 446 if (j < rename_dst_nr) 447 /* this path remains */ 448 pair_to_free = p; 449 } 450 451 if (pair_to_free) 452 ; 453 else 454 diff_q(&outq, p); 455 } 456 else if (!diff_unmodified_pair(p)) 457 /* all the usual ones need to be kept */ 458 diff_q(&outq, p); 459 else 460 /* no need to keep unmodified pairs */ 461 pair_to_free = p; 462 463 if (pair_to_free) 464 diff_free_filepair(pair_to_free); 465 } 466 diff_debug_queue("done copying original", &outq); 467 468 free(q->queue); 469 *q = outq; 470 diff_debug_queue("done collapsing", q); 471 472 /* We need to see which rename source really stays here; 473 * earlier we only checked if the path is left in the result, 474 * but even if a path remains in the result, if that is coming 475 * from copying something else on top of it, then the original 476 * source is lost and does not stay. 477 */ 478 for (i = 0; i < q->nr; i++) { 479 struct diff_filepair *p = q->queue[i]; 480 if (DIFF_PAIR_RENAME(p) && p->source_stays) { 481 /* If one appears as the target of a rename-copy, 482 * then mark p->source_stays = 0; otherwise 483 * leave it as is. 484 */ 485 p->source_stays = compute_stays(q, p->one); 486 } 487 } 488 489 for (i = 0; i < rename_dst_nr; i++) { 490 diff_free_filespec_data(rename_dst[i].two); 491 free(rename_dst[i].two); 492 } 493 494 free(rename_dst); 495 rename_dst = NULL; 496 rename_dst_nr = rename_dst_alloc = 0; 497 free(rename_src); 498 rename_src = NULL; 499 rename_src_nr = rename_src_alloc = 0; 500 return; 501}