1/* 2 * Copyright (C) 2005 Junio C Hamano 3 */ 4#include "cache.h" 5#include "diff.h" 6#include "diffcore.h" 7#include "object-store.h" 8#include "hashmap.h" 9#include "progress.h" 10 11/* Table of rename/copy destinations */ 12 13static struct diff_rename_dst { 14 struct diff_filespec *two; 15 struct diff_filepair *pair; 16} *rename_dst; 17static int rename_dst_nr, rename_dst_alloc; 18 19static int find_rename_dst(struct diff_filespec *two) 20{ 21 int first, last; 22 23 first = 0; 24 last = rename_dst_nr; 25 while (last > first) { 26 int next = (last + first) >> 1; 27 struct diff_rename_dst *dst = &(rename_dst[next]); 28 int cmp = strcmp(two->path, dst->two->path); 29 if (!cmp) 30 return next; 31 if (cmp < 0) { 32 last = next; 33 continue; 34 } 35 first = next+1; 36 } 37 return -first - 1; 38} 39 40static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two) 41{ 42 int ofs = find_rename_dst(two); 43 return ofs < 0 ? NULL : &rename_dst[ofs]; 44} 45 46/* 47 * Returns 0 on success, -1 if we found a duplicate. 48 */ 49static int add_rename_dst(struct diff_filespec *two) 50{ 51 int first = find_rename_dst(two); 52 53 if (first >= 0) 54 return -1; 55 first = -first - 1; 56 57 /* insert to make it at "first" */ 58 ALLOC_GROW(rename_dst, rename_dst_nr + 1, rename_dst_alloc); 59 rename_dst_nr++; 60 if (first < rename_dst_nr) 61 MOVE_ARRAY(rename_dst + first + 1, rename_dst + first, 62 rename_dst_nr - first - 1); 63 rename_dst[first].two = alloc_filespec(two->path); 64 fill_filespec(rename_dst[first].two, &two->oid, two->oid_valid, 65 two->mode); 66 rename_dst[first].pair = NULL; 67 return 0; 68} 69 70/* Table of rename/copy src files */ 71static struct diff_rename_src { 72 struct diff_filepair *p; 73 unsigned short score; /* to remember the break score */ 74} *rename_src; 75static int rename_src_nr, rename_src_alloc; 76 77static struct diff_rename_src *register_rename_src(struct diff_filepair *p) 78{ 79 int first, last; 80 struct diff_filespec *one = p->one; 81 unsigned short score = p->score; 82 83 first = 0; 84 last = rename_src_nr; 85 while (last > first) { 86 int next = (last + first) >> 1; 87 struct diff_rename_src *src = &(rename_src[next]); 88 int cmp = strcmp(one->path, src->p->one->path); 89 if (!cmp) 90 return src; 91 if (cmp < 0) { 92 last = next; 93 continue; 94 } 95 first = next+1; 96 } 97 98 /* insert to make it at "first" */ 99 ALLOC_GROW(rename_src, rename_src_nr + 1, rename_src_alloc); 100 rename_src_nr++; 101 if (first < rename_src_nr) 102 MOVE_ARRAY(rename_src + first + 1, rename_src + first, 103 rename_src_nr - first - 1); 104 rename_src[first].p = p; 105 rename_src[first].score = score; 106 return &(rename_src[first]); 107} 108 109static int basename_same(struct diff_filespec *src, struct diff_filespec *dst) 110{ 111 int src_len = strlen(src->path), dst_len = strlen(dst->path); 112 while (src_len && dst_len) { 113 char c1 = src->path[--src_len]; 114 char c2 = dst->path[--dst_len]; 115 if (c1 != c2) 116 return 0; 117 if (c1 == '/') 118 return 1; 119 } 120 return (!src_len || src->path[src_len - 1] == '/') && 121 (!dst_len || dst->path[dst_len - 1] == '/'); 122} 123 124struct diff_score { 125 int src; /* index in rename_src */ 126 int dst; /* index in rename_dst */ 127 unsigned short score; 128 short name_score; 129}; 130 131static int estimate_similarity(struct diff_filespec *src, 132 struct diff_filespec *dst, 133 int minimum_score) 134{ 135 /* src points at a file that existed in the original tree (or 136 * optionally a file in the destination tree) and dst points 137 * at a newly created file. They may be quite similar, in which 138 * case we want to say src is renamed to dst or src is copied into 139 * dst, and then some edit has been applied to dst. 140 * 141 * Compare them and return how similar they are, representing 142 * the score as an integer between 0 and MAX_SCORE. 143 * 144 * When there is an exact match, it is considered a better 145 * match than anything else; the destination does not even 146 * call into this function in that case. 147 */ 148 unsigned long max_size, delta_size, base_size, src_copied, literal_added; 149 int score; 150 151 /* We deal only with regular files. Symlink renames are handled 152 * only when they are exact matches --- in other words, no edits 153 * after renaming. 154 */ 155 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode)) 156 return 0; 157 158 /* 159 * Need to check that source and destination sizes are 160 * filled in before comparing them. 161 * 162 * If we already have "cnt_data" filled in, we know it's 163 * all good (avoid checking the size for zero, as that 164 * is a possible size - we really should have a flag to 165 * say whether the size is valid or not!) 166 */ 167 if (!src->cnt_data && 168 diff_populate_filespec(src, CHECK_SIZE_ONLY)) 169 return 0; 170 if (!dst->cnt_data && 171 diff_populate_filespec(dst, CHECK_SIZE_ONLY)) 172 return 0; 173 174 max_size = ((src->size > dst->size) ? src->size : dst->size); 175 base_size = ((src->size < dst->size) ? src->size : dst->size); 176 delta_size = max_size - base_size; 177 178 /* We would not consider edits that change the file size so 179 * drastically. delta_size must be smaller than 180 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size). 181 * 182 * Note that base_size == 0 case is handled here already 183 * and the final score computation below would not have a 184 * divide-by-zero issue. 185 */ 186 if (max_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) 187 return 0; 188 189 if (!src->cnt_data && diff_populate_filespec(src, 0)) 190 return 0; 191 if (!dst->cnt_data && diff_populate_filespec(dst, 0)) 192 return 0; 193 194 if (diffcore_count_changes(src, dst, 195 &src->cnt_data, &dst->cnt_data, 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 return score; 207} 208 209static void record_rename_pair(int dst_index, int src_index, int score) 210{ 211 struct diff_filespec *src, *dst; 212 struct diff_filepair *dp; 213 214 if (rename_dst[dst_index].pair) 215 die("internal error: dst already matched."); 216 217 src = rename_src[src_index].p->one; 218 src->rename_used++; 219 src->count++; 220 221 dst = rename_dst[dst_index].two; 222 dst->count++; 223 224 dp = diff_queue(NULL, src, dst); 225 dp->renamed_pair = 1; 226 if (!strcmp(src->path, dst->path)) 227 dp->score = rename_src[src_index].score; 228 else 229 dp->score = score; 230 rename_dst[dst_index].pair = dp; 231} 232 233/* 234 * We sort the rename similarity matrix with the score, in descending 235 * order (the most similar first). 236 */ 237static int score_compare(const void *a_, const void *b_) 238{ 239 const struct diff_score *a = a_, *b = b_; 240 241 /* sink the unused ones to the bottom */ 242 if (a->dst < 0) 243 return (0 <= b->dst); 244 else if (b->dst < 0) 245 return -1; 246 247 if (a->score == b->score) 248 return b->name_score - a->name_score; 249 250 return b->score - a->score; 251} 252 253struct file_similarity { 254 struct hashmap_entry entry; 255 int index; 256 struct diff_filespec *filespec; 257}; 258 259static unsigned int hash_filespec(struct diff_filespec *filespec) 260{ 261 if (!filespec->oid_valid) { 262 if (diff_populate_filespec(filespec, 0)) 263 return 0; 264 hash_object_file(filespec->data, filespec->size, "blob", 265 &filespec->oid); 266 } 267 return sha1hash(filespec->oid.hash); 268} 269 270static int find_identical_files(struct hashmap *srcs, 271 int dst_index, 272 struct diff_options *options) 273{ 274 int renames = 0; 275 276 struct diff_filespec *target = rename_dst[dst_index].two; 277 struct file_similarity *p, *best = NULL; 278 int i = 100, best_score = -1; 279 280 /* 281 * Find the best source match for specified destination. 282 */ 283 p = hashmap_get_from_hash(srcs, hash_filespec(target), NULL); 284 for (; p; p = hashmap_get_next(srcs, p)) { 285 int score; 286 struct diff_filespec *source = p->filespec; 287 288 /* False hash collision? */ 289 if (oidcmp(&source->oid, &target->oid)) 290 continue; 291 /* Non-regular files? If so, the modes must match! */ 292 if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) { 293 if (source->mode != target->mode) 294 continue; 295 } 296 /* Give higher scores to sources that haven't been used already */ 297 score = !source->rename_used; 298 if (source->rename_used && options->detect_rename != DIFF_DETECT_COPY) 299 continue; 300 score += basename_same(source, target); 301 if (score > best_score) { 302 best = p; 303 best_score = score; 304 if (score == 2) 305 break; 306 } 307 308 /* Too many identical alternatives? Pick one */ 309 if (!--i) 310 break; 311 } 312 if (best) { 313 record_rename_pair(dst_index, best->index, MAX_SCORE); 314 renames++; 315 } 316 return renames; 317} 318 319static void insert_file_table(struct hashmap *table, int index, struct diff_filespec *filespec) 320{ 321 struct file_similarity *entry = xmalloc(sizeof(*entry)); 322 323 entry->index = index; 324 entry->filespec = filespec; 325 326 hashmap_entry_init(entry, hash_filespec(filespec)); 327 hashmap_add(table, entry); 328} 329 330/* 331 * Find exact renames first. 332 * 333 * The first round matches up the up-to-date entries, 334 * and then during the second round we try to match 335 * cache-dirty entries as well. 336 */ 337static int find_exact_renames(struct diff_options *options) 338{ 339 int i, renames = 0; 340 struct hashmap file_table; 341 342 /* Add all sources to the hash table in reverse order, because 343 * later on they will be retrieved in LIFO order. 344 */ 345 hashmap_init(&file_table, NULL, NULL, rename_src_nr); 346 for (i = rename_src_nr-1; i >= 0; i--) 347 insert_file_table(&file_table, i, rename_src[i].p->one); 348 349 /* Walk the destinations and find best source match */ 350 for (i = 0; i < rename_dst_nr; i++) 351 renames += find_identical_files(&file_table, i, options); 352 353 /* Free the hash data structure and entries */ 354 hashmap_free(&file_table, 1); 355 356 return renames; 357} 358 359#define NUM_CANDIDATE_PER_DST 4 360static void record_if_better(struct diff_score m[], struct diff_score *o) 361{ 362 int i, worst; 363 364 /* find the worst one */ 365 worst = 0; 366 for (i = 1; i < NUM_CANDIDATE_PER_DST; i++) 367 if (score_compare(&m[i], &m[worst]) > 0) 368 worst = i; 369 370 /* is it better than the worst one? */ 371 if (score_compare(&m[worst], o) > 0) 372 m[worst] = *o; 373} 374 375/* 376 * Returns: 377 * 0 if we are under the limit; 378 * 1 if we need to disable inexact rename detection; 379 * 2 if we would be under the limit if we were given -C instead of -C -C. 380 */ 381static int too_many_rename_candidates(int num_create, 382 struct diff_options *options) 383{ 384 int rename_limit = options->rename_limit; 385 int num_src = rename_src_nr; 386 int i; 387 388 options->needed_rename_limit = 0; 389 390 /* 391 * This basically does a test for the rename matrix not 392 * growing larger than a "rename_limit" square matrix, ie: 393 * 394 * num_create * num_src > rename_limit * rename_limit 395 */ 396 if (rename_limit <= 0) 397 rename_limit = 32767; 398 if ((num_create <= rename_limit || num_src <= rename_limit) && 399 ((uint64_t)num_create * (uint64_t)num_src 400 <= (uint64_t)rename_limit * (uint64_t)rename_limit)) 401 return 0; 402 403 options->needed_rename_limit = 404 num_src > num_create ? num_src : num_create; 405 406 /* Are we running under -C -C? */ 407 if (!options->flags.find_copies_harder) 408 return 1; 409 410 /* Would we bust the limit if we were running under -C? */ 411 for (num_src = i = 0; i < rename_src_nr; i++) { 412 if (diff_unmodified_pair(rename_src[i].p)) 413 continue; 414 num_src++; 415 } 416 if ((num_create <= rename_limit || num_src <= rename_limit) && 417 ((uint64_t)num_create * (uint64_t)num_src 418 <= (uint64_t)rename_limit * (uint64_t)rename_limit)) 419 return 2; 420 return 1; 421} 422 423static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, int copies) 424{ 425 int count = 0, i; 426 427 for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) { 428 struct diff_rename_dst *dst; 429 430 if ((mx[i].dst < 0) || 431 (mx[i].score < minimum_score)) 432 break; /* there is no more usable pair. */ 433 dst = &rename_dst[mx[i].dst]; 434 if (dst->pair) 435 continue; /* already done, either exact or fuzzy. */ 436 if (!copies && rename_src[mx[i].src].p->one->rename_used) 437 continue; 438 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 439 count++; 440 } 441 return count; 442} 443 444void diffcore_rename(struct diff_options *options) 445{ 446 int detect_rename = options->detect_rename; 447 int minimum_score = options->rename_score; 448 struct diff_queue_struct *q = &diff_queued_diff; 449 struct diff_queue_struct outq; 450 struct diff_score *mx; 451 int i, j, rename_count, skip_unmodified = 0; 452 int num_create, dst_cnt; 453 struct progress *progress = NULL; 454 455 if (!minimum_score) 456 minimum_score = DEFAULT_RENAME_SCORE; 457 458 for (i = 0; i < q->nr; i++) { 459 struct diff_filepair *p = q->queue[i]; 460 if (!DIFF_FILE_VALID(p->one)) { 461 if (!DIFF_FILE_VALID(p->two)) 462 continue; /* unmerged */ 463 else if (options->single_follow && 464 strcmp(options->single_follow, p->two->path)) 465 continue; /* not interested */ 466 else if (!options->flags.rename_empty && 467 is_empty_blob_oid(&p->two->oid)) 468 continue; 469 else if (add_rename_dst(p->two) < 0) { 470 warning("skipping rename detection, detected" 471 " duplicate destination '%s'", 472 p->two->path); 473 goto cleanup; 474 } 475 } 476 else if (!options->flags.rename_empty && 477 is_empty_blob_oid(&p->one->oid)) 478 continue; 479 else if (!DIFF_PAIR_UNMERGED(p) && !DIFF_FILE_VALID(p->two)) { 480 /* 481 * If the source is a broken "delete", and 482 * they did not really want to get broken, 483 * that means the source actually stays. 484 * So we increment the "rename_used" score 485 * by one, to indicate ourselves as a user 486 */ 487 if (p->broken_pair && !p->score) 488 p->one->rename_used++; 489 register_rename_src(p); 490 } 491 else if (detect_rename == DIFF_DETECT_COPY) { 492 /* 493 * Increment the "rename_used" score by 494 * one, to indicate ourselves as a user. 495 */ 496 p->one->rename_used++; 497 register_rename_src(p); 498 } 499 } 500 if (rename_dst_nr == 0 || rename_src_nr == 0) 501 goto cleanup; /* nothing to do */ 502 503 /* 504 * We really want to cull the candidates list early 505 * with cheap tests in order to avoid doing deltas. 506 */ 507 rename_count = find_exact_renames(options); 508 509 /* Did we only want exact renames? */ 510 if (minimum_score == MAX_SCORE) 511 goto cleanup; 512 513 /* 514 * Calculate how many renames are left (but all the source 515 * files still remain as options for rename/copies!) 516 */ 517 num_create = (rename_dst_nr - rename_count); 518 519 /* All done? */ 520 if (!num_create) 521 goto cleanup; 522 523 switch (too_many_rename_candidates(num_create, options)) { 524 case 1: 525 goto cleanup; 526 case 2: 527 options->degraded_cc_to_c = 1; 528 skip_unmodified = 1; 529 break; 530 default: 531 break; 532 } 533 534 if (options->show_rename_progress) { 535 progress = start_delayed_progress( 536 _("Performing inexact rename detection"), 537 (uint64_t)rename_dst_nr * (uint64_t)rename_src_nr); 538 } 539 540 mx = xcalloc(st_mult(NUM_CANDIDATE_PER_DST, num_create), sizeof(*mx)); 541 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 542 struct diff_filespec *two = rename_dst[i].two; 543 struct diff_score *m; 544 545 if (rename_dst[i].pair) 546 continue; /* dealt with exact match already. */ 547 548 m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST]; 549 for (j = 0; j < NUM_CANDIDATE_PER_DST; j++) 550 m[j].dst = -1; 551 552 for (j = 0; j < rename_src_nr; j++) { 553 struct diff_filespec *one = rename_src[j].p->one; 554 struct diff_score this_src; 555 556 if (skip_unmodified && 557 diff_unmodified_pair(rename_src[j].p)) 558 continue; 559 560 this_src.score = estimate_similarity(one, two, 561 minimum_score); 562 this_src.name_score = basename_same(one, two); 563 this_src.dst = i; 564 this_src.src = j; 565 record_if_better(m, &this_src); 566 /* 567 * Once we run estimate_similarity, 568 * We do not need the text anymore. 569 */ 570 diff_free_filespec_blob(one); 571 diff_free_filespec_blob(two); 572 } 573 dst_cnt++; 574 display_progress(progress, (uint64_t)(i+1)*(uint64_t)rename_src_nr); 575 } 576 stop_progress(&progress); 577 578 /* cost matrix sorted by most to least similar pair */ 579 QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare); 580 581 rename_count += find_renames(mx, dst_cnt, minimum_score, 0); 582 if (detect_rename == DIFF_DETECT_COPY) 583 rename_count += find_renames(mx, dst_cnt, minimum_score, 1); 584 free(mx); 585 586 cleanup: 587 /* At this point, we have found some renames and copies and they 588 * are recorded in rename_dst. The original list is still in *q. 589 */ 590 DIFF_QUEUE_CLEAR(&outq); 591 for (i = 0; i < q->nr; i++) { 592 struct diff_filepair *p = q->queue[i]; 593 struct diff_filepair *pair_to_free = NULL; 594 595 if (DIFF_PAIR_UNMERGED(p)) { 596 diff_q(&outq, p); 597 } 598 else if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 599 /* 600 * Creation 601 * 602 * We would output this create record if it has 603 * not been turned into a rename/copy already. 604 */ 605 struct diff_rename_dst *dst = locate_rename_dst(p->two); 606 if (dst && dst->pair) { 607 diff_q(&outq, dst->pair); 608 pair_to_free = p; 609 } 610 else 611 /* no matching rename/copy source, so 612 * record this as a creation. 613 */ 614 diff_q(&outq, p); 615 } 616 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 617 /* 618 * Deletion 619 * 620 * We would output this delete record if: 621 * 622 * (1) this is a broken delete and the counterpart 623 * broken create remains in the output; or 624 * (2) this is not a broken delete, and rename_dst 625 * does not have a rename/copy to move p->one->path 626 * out of existence. 627 * 628 * Otherwise, the counterpart broken create 629 * has been turned into a rename-edit; or 630 * delete did not have a matching create to 631 * begin with. 632 */ 633 if (DIFF_PAIR_BROKEN(p)) { 634 /* broken delete */ 635 struct diff_rename_dst *dst = locate_rename_dst(p->one); 636 if (dst && dst->pair) 637 /* counterpart is now rename/copy */ 638 pair_to_free = p; 639 } 640 else { 641 if (p->one->rename_used) 642 /* this path remains */ 643 pair_to_free = p; 644 } 645 646 if (pair_to_free) 647 ; 648 else 649 diff_q(&outq, p); 650 } 651 else if (!diff_unmodified_pair(p)) 652 /* all the usual ones need to be kept */ 653 diff_q(&outq, p); 654 else 655 /* no need to keep unmodified pairs */ 656 pair_to_free = p; 657 658 if (pair_to_free) 659 diff_free_filepair(pair_to_free); 660 } 661 diff_debug_queue("done copying original", &outq); 662 663 free(q->queue); 664 *q = outq; 665 diff_debug_queue("done collapsing", q); 666 667 for (i = 0; i < rename_dst_nr; i++) 668 free_filespec(rename_dst[i].two); 669 670 FREE_AND_NULL(rename_dst); 671 rename_dst_nr = rename_dst_alloc = 0; 672 FREE_AND_NULL(rename_src); 673 rename_src_nr = rename_src_alloc = 0; 674 return; 675}