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 = (unsigned long) 176 (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE); 177 if (diffcore_count_changes(src->data, src->size, 178 dst->data, dst->size, 179 &src->cnt_data, &dst->cnt_data, 180 delta_limit, 181 &src_copied, &literal_added)) 182 return 0; 183 184 /* How similar are they? 185 * what percentage of material in dst are from source? 186 */ 187 if (!dst->size) 188 score = 0; /* should not happen */ 189 else 190 score = (int)(src_copied * MAX_SCORE / max_size); 191 return score; 192} 193 194static void record_rename_pair(int dst_index, int src_index, int score) 195{ 196 struct diff_filespec *one, *two, *src, *dst; 197 struct diff_filepair *dp; 198 199 if (rename_dst[dst_index].pair) 200 die("internal error: dst already matched."); 201 202 src = rename_src[src_index].one; 203 one = alloc_filespec(src->path); 204 fill_filespec(one, src->sha1, src->mode); 205 206 dst = rename_dst[dst_index].two; 207 two = alloc_filespec(dst->path); 208 fill_filespec(two, dst->sha1, dst->mode); 209 210 dp = diff_queue(NULL, one, two); 211 dp->renamed_pair = 1; 212 if (!strcmp(src->path, dst->path)) 213 dp->score = rename_src[src_index].score; 214 else 215 dp->score = score; 216 dp->source_stays = rename_src[src_index].src_path_left; 217 rename_dst[dst_index].pair = dp; 218} 219 220/* 221 * We sort the rename similarity matrix with the score, in descending 222 * order (the most similar first). 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 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 245void diffcore_rename(struct diff_options *options) 246{ 247 int detect_rename = options->detect_rename; 248 int minimum_score = options->rename_score; 249 int rename_limit = options->rename_limit; 250 struct diff_queue_struct *q = &diff_queued_diff; 251 struct diff_queue_struct outq; 252 struct diff_score *mx; 253 int i, j, rename_count, contents_too; 254 int num_create, num_src, dst_cnt; 255 256 if (!minimum_score) 257 minimum_score = DEFAULT_RENAME_SCORE; 258 rename_count = 0; 259 260 for (i = 0; i < q->nr; i++) { 261 struct diff_filepair *p = q->queue[i]; 262 if (!DIFF_FILE_VALID(p->one)) { 263 if (!DIFF_FILE_VALID(p->two)) 264 continue; /* unmerged */ 265 else if (options->single_follow && 266 strcmp(options->single_follow, p->two->path)) 267 continue; /* not interested */ 268 else 269 locate_rename_dst(p->two, 1); 270 } 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); 277 register_rename_src(p->one, stays, p->score); 278 } 279 else if (detect_rename == DIFF_DETECT_COPY) 280 register_rename_src(p->one, 1, p->score); 281 } 282 if (rename_dst_nr == 0 || rename_src_nr == 0 || 283 (0 < rename_limit && rename_limit < rename_dst_nr)) 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. 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. 291 */ 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; 301 record_rename_pair(i, j, (int)MAX_SCORE); 302 rename_count++; 303 break; /* we are done with this entry */ 304 } 305 } 306 } 307 308 /* Have we run out the created file pool? If so we can avoid 309 * doing the delta matrix altogether. 310 */ 311 if (rename_count == rename_dst_nr) 312 goto cleanup; 313 314 if (minimum_score == MAX_SCORE) 315 goto cleanup; 316 317 num_create = (rename_dst_nr - rename_count); 318 num_src = rename_src_nr; 319 mx = xmalloc(sizeof(*mx) * num_create * num_src); 320 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 321 int base = dst_cnt * num_src; 322 struct diff_filespec *two = rename_dst[i].two; 323 if (rename_dst[i].pair) 324 continue; /* dealt with exact match already. */ 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); 332 } 333 /* We do not need the text anymore */ 334 diff_free_filespec_data(two); 335 dst_cnt++; 336 } 337 /* cost matrix sorted by most to least similar pair */ 338 qsort(mx, num_create * num_src, sizeof(*mx), score_compare); 339 for (i = 0; i < num_create * num_src; i++) { 340 struct diff_rename_dst *dst = &rename_dst[mx[i].dst]; 341 if (dst->pair) 342 continue; /* already done, either exact or fuzzy. */ 343 if (mx[i].score < minimum_score) 344 break; /* there is no more usable pair. */ 345 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 346 rename_count++; 347 } 348 free(mx); 349 350 cleanup: 351 /* At this point, we have found some renames and copies and they 352 * are recorded in rename_dst. The original list is still in *q. 353 */ 354 outq.queue = NULL; 355 outq.nr = outq.alloc = 0; 356 for (i = 0; i < q->nr; i++) { 357 struct diff_filepair *p = q->queue[i]; 358 struct diff_filepair *pair_to_free = NULL; 359 360 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 361 /* 362 * Creation 363 * 364 * We would output this create record if it has 365 * not been turned into a rename/copy already. 366 */ 367 struct diff_rename_dst *dst = 368 locate_rename_dst(p->two, 0); 369 if (dst && dst->pair) { 370 diff_q(&outq, dst->pair); 371 pair_to_free = p; 372 } 373 else 374 /* no matching rename/copy source, so 375 * record this as a creation. 376 */ 377 diff_q(&outq, p); 378 } 379 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 380 /* 381 * Deletion 382 * 383 * We would output this delete record if: 384 * 385 * (1) this is a broken delete and the counterpart 386 * broken create remains in the output; or 387 * (2) this is not a broken delete, and rename_dst 388 * does not have a rename/copy to move p->one->path 389 * out of existence. 390 * 391 * Otherwise, the counterpart broken create 392 * has been turned into a rename-edit; or 393 * delete did not have a matching create to 394 * begin with. 395 */ 396 if (DIFF_PAIR_BROKEN(p)) { 397 /* broken delete */ 398 struct diff_rename_dst *dst = 399 locate_rename_dst(p->one, 0); 400 if (dst && dst->pair) 401 /* counterpart is now rename/copy */ 402 pair_to_free = p; 403 } 404 else { 405 for (j = 0; j < rename_dst_nr; j++) { 406 if (!rename_dst[j].pair) 407 continue; 408 if (strcmp(rename_dst[j].pair-> 409 one->path, 410 p->one->path)) 411 continue; 412 break; 413 } 414 if (j < rename_dst_nr) 415 /* this path remains */ 416 pair_to_free = p; 417 } 418 419 if (pair_to_free) 420 ; 421 else 422 diff_q(&outq, p); 423 } 424 else if (!diff_unmodified_pair(p)) 425 /* all the usual ones need to be kept */ 426 diff_q(&outq, p); 427 else 428 /* no need to keep unmodified pairs */ 429 pair_to_free = p; 430 431 if (pair_to_free) 432 diff_free_filepair(pair_to_free); 433 } 434 diff_debug_queue("done copying original", &outq); 435 436 free(q->queue); 437 *q = outq; 438 diff_debug_queue("done collapsing", q); 439 440 /* We need to see which rename source really stays here; 441 * earlier we only checked if the path is left in the result, 442 * but even if a path remains in the result, if that is coming 443 * from copying something else on top of it, then the original 444 * source is lost and does not stay. 445 */ 446 for (i = 0; i < q->nr; i++) { 447 struct diff_filepair *p = q->queue[i]; 448 if (DIFF_PAIR_RENAME(p) && p->source_stays) { 449 /* If one appears as the target of a rename-copy, 450 * then mark p->source_stays = 0; otherwise 451 * leave it as is. 452 */ 453 p->source_stays = compute_stays(q, p->one); 454 } 455 } 456 457 for (i = 0; i < rename_dst_nr; i++) { 458 diff_free_filespec_data(rename_dst[i].two); 459 free(rename_dst[i].two); 460 } 461 462 free(rename_dst); 463 rename_dst = NULL; 464 rename_dst_nr = rename_dst_alloc = 0; 465 free(rename_src); 466 rename_src = NULL; 467 rename_src_nr = rename_src_alloc = 0; 468 return; 469}