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 !memcmp(src->sha1, dst->sha1, 20)) 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 (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 113 return 0; 114 if (src->size == dst->size && 115 !memcmp(src->data, dst->data, src->size)) 116 return 1; 117 return 0; 118} 119 120struct diff_score { 121 int src; /* index in rename_src */ 122 int dst; /* index in rename_dst */ 123 int score; 124}; 125 126static int estimate_similarity(struct diff_filespec *src, 127 struct diff_filespec *dst, 128 int minimum_score) 129{ 130 /* src points at a file that existed in the original tree (or 131 * optionally a file in the destination tree) and dst points 132 * at a newly created file. They may be quite similar, in which 133 * case we want to say src is renamed to dst or src is copied into 134 * dst, and then some edit has been applied to dst. 135 * 136 * Compare them and return how similar they are, representing 137 * the score as an integer between 0 and MAX_SCORE. 138 * 139 * When there is an exact match, it is considered a better 140 * match than anything else; the destination does not even 141 * call into this function in that case. 142 */ 143 unsigned long max_size, delta_size, base_size, src_copied, literal_added; 144 unsigned long delta_limit; 145 int score; 146 147 /* We deal only with regular files. Symlink renames are handled 148 * only when they are exact matches --- in other words, no edits 149 * after renaming. 150 */ 151 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode)) 152 return 0; 153 154 max_size = ((src->size > dst->size) ? src->size : dst->size); 155 base_size = ((src->size < dst->size) ? src->size : dst->size); 156 delta_size = max_size - base_size; 157 158 /* We would not consider edits that change the file size so 159 * drastically. delta_size must be smaller than 160 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size). 161 * 162 * Note that base_size == 0 case is handled here already 163 * and the final score computation below would not have a 164 * divide-by-zero issue. 165 */ 166 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) 167 return 0; 168 169 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 170 return 0; /* error but caught downstream */ 171 172 173 delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE; 174 if (diffcore_count_changes(src->data, src->size, 175 dst->data, dst->size, 176 &src->cnt_data, &dst->cnt_data, 177 delta_limit, 178 &src_copied, &literal_added)) 179 return 0; 180 181 /* How similar are they? 182 * what percentage of material in dst are from source? 183 */ 184 if (!dst->size) 185 score = 0; /* should not happen */ 186 else 187 score = src_copied * MAX_SCORE / max_size; 188 return score; 189} 190 191static void record_rename_pair(int dst_index, int src_index, int score) 192{ 193 struct diff_filespec *one, *two, *src, *dst; 194 struct diff_filepair *dp; 195 196 if (rename_dst[dst_index].pair) 197 die("internal error: dst already matched."); 198 199 src = rename_src[src_index].one; 200 one = alloc_filespec(src->path); 201 fill_filespec(one, src->sha1, src->mode); 202 203 dst = rename_dst[dst_index].two; 204 two = alloc_filespec(dst->path); 205 fill_filespec(two, dst->sha1, dst->mode); 206 207 dp = diff_queue(NULL, one, two); 208 if (!strcmp(src->path, dst->path)) 209 dp->score = rename_src[src_index].score; 210 else 211 dp->score = score; 212 dp->source_stays = rename_src[src_index].src_path_left; 213 rename_dst[dst_index].pair = dp; 214} 215 216/* 217 * We sort the rename similarity matrix with the score, in descending 218 * order (the most similar first). 219 */ 220static int score_compare(const void *a_, const void *b_) 221{ 222 const struct diff_score *a = a_, *b = b_; 223 return b->score - a->score; 224} 225 226static int compute_stays(struct diff_queue_struct *q, 227 struct diff_filespec *one) 228{ 229 int i; 230 for (i = 0; i < q->nr; i++) { 231 struct diff_filepair *p = q->queue[i]; 232 if (strcmp(one->path, p->two->path)) 233 continue; 234 if (DIFF_PAIR_RENAME(p)) { 235 return 0; /* something else is renamed into this */ 236 } 237 } 238 return 1; 239} 240 241void diffcore_rename(struct diff_options *options) 242{ 243 int detect_rename = options->detect_rename; 244 int minimum_score = options->rename_score; 245 int rename_limit = options->rename_limit; 246 struct diff_queue_struct *q = &diff_queued_diff; 247 struct diff_queue_struct outq; 248 struct diff_score *mx; 249 int i, j, rename_count, contents_too; 250 int num_create, num_src, dst_cnt; 251 252 if (!minimum_score) 253 minimum_score = DEFAULT_RENAME_SCORE; 254 rename_count = 0; 255 256 for (i = 0; i < q->nr; i++) { 257 struct diff_filepair *p = q->queue[i]; 258 if (!DIFF_FILE_VALID(p->one)) 259 if (!DIFF_FILE_VALID(p->two)) 260 continue; /* unmerged */ 261 else 262 locate_rename_dst(p->two, 1); 263 else if (!DIFF_FILE_VALID(p->two)) { 264 /* If the source is a broken "delete", and 265 * they did not really want to get broken, 266 * that means the source actually stays. 267 */ 268 int stays = (p->broken_pair && !p->score); 269 register_rename_src(p->one, stays, p->score); 270 } 271 else if (detect_rename == DIFF_DETECT_COPY) 272 register_rename_src(p->one, 1, p->score); 273 } 274 if (rename_dst_nr == 0 || rename_src_nr == 0 || 275 (0 < rename_limit && rename_limit < rename_dst_nr)) 276 goto cleanup; /* nothing to do */ 277 278 /* We really want to cull the candidates list early 279 * with cheap tests in order to avoid doing deltas. 280 * The first round matches up the up-to-date entries, 281 * and then during the second round we try to match 282 * cache-dirty entries as well. 283 */ 284 for (contents_too = 0; contents_too < 2; contents_too++) { 285 for (i = 0; i < rename_dst_nr; i++) { 286 struct diff_filespec *two = rename_dst[i].two; 287 if (rename_dst[i].pair) 288 continue; /* dealt with an earlier round */ 289 for (j = 0; j < rename_src_nr; j++) { 290 struct diff_filespec *one = rename_src[j].one; 291 if (!is_exact_match(one, two, contents_too)) 292 continue; 293 record_rename_pair(i, j, MAX_SCORE); 294 rename_count++; 295 break; /* we are done with this entry */ 296 } 297 } 298 } 299 300 /* Have we run out the created file pool? If so we can avoid 301 * doing the delta matrix altogether. 302 */ 303 if (rename_count == rename_dst_nr) 304 goto cleanup; 305 306 if (minimum_score == MAX_SCORE) 307 goto cleanup; 308 309 num_create = (rename_dst_nr - rename_count); 310 num_src = rename_src_nr; 311 mx = xmalloc(sizeof(*mx) * num_create * num_src); 312 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 313 int base = dst_cnt * num_src; 314 struct diff_filespec *two = rename_dst[i].two; 315 if (rename_dst[i].pair) 316 continue; /* dealt with exact match already. */ 317 for (j = 0; j < rename_src_nr; j++) { 318 struct diff_filespec *one = rename_src[j].one; 319 struct diff_score *m = &mx[base+j]; 320 m->src = j; 321 m->dst = i; 322 m->score = estimate_similarity(one, two, 323 minimum_score); 324 } 325 /* We do not need the text anymore */ 326 diff_free_filespec_data(two); 327 dst_cnt++; 328 } 329 /* cost matrix sorted by most to least similar pair */ 330 qsort(mx, num_create * num_src, sizeof(*mx), score_compare); 331 for (i = 0; i < num_create * num_src; i++) { 332 struct diff_rename_dst *dst = &rename_dst[mx[i].dst]; 333 if (dst->pair) 334 continue; /* already done, either exact or fuzzy. */ 335 if (mx[i].score < minimum_score) 336 break; /* there is no more usable pair. */ 337 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 338 rename_count++; 339 } 340 free(mx); 341 342 cleanup: 343 /* At this point, we have found some renames and copies and they 344 * are recorded in rename_dst. The original list is still in *q. 345 */ 346 outq.queue = NULL; 347 outq.nr = outq.alloc = 0; 348 for (i = 0; i < q->nr; i++) { 349 struct diff_filepair *p = q->queue[i]; 350 struct diff_filepair *pair_to_free = NULL; 351 352 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 353 /* 354 * Creation 355 * 356 * We would output this create record if it has 357 * not been turned into a rename/copy already. 358 */ 359 struct diff_rename_dst *dst = 360 locate_rename_dst(p->two, 0); 361 if (dst && dst->pair) { 362 diff_q(&outq, dst->pair); 363 pair_to_free = p; 364 } 365 else 366 /* no matching rename/copy source, so 367 * record this as a creation. 368 */ 369 diff_q(&outq, p); 370 } 371 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 372 /* 373 * Deletion 374 * 375 * We would output this delete record if: 376 * 377 * (1) this is a broken delete and the counterpart 378 * broken create remains in the output; or 379 * (2) this is not a broken delete, and rename_dst 380 * does not have a rename/copy to move p->one->path 381 * out of existence. 382 * 383 * Otherwise, the counterpart broken create 384 * has been turned into a rename-edit; or 385 * delete did not have a matching create to 386 * begin with. 387 */ 388 if (DIFF_PAIR_BROKEN(p)) { 389 /* broken delete */ 390 struct diff_rename_dst *dst = 391 locate_rename_dst(p->one, 0); 392 if (dst && dst->pair) 393 /* counterpart is now rename/copy */ 394 pair_to_free = p; 395 } 396 else { 397 for (j = 0; j < rename_dst_nr; j++) { 398 if (!rename_dst[j].pair) 399 continue; 400 if (strcmp(rename_dst[j].pair-> 401 one->path, 402 p->one->path)) 403 continue; 404 break; 405 } 406 if (j < rename_dst_nr) 407 /* this path remains */ 408 pair_to_free = p; 409 } 410 411 if (pair_to_free) 412 ; 413 else 414 diff_q(&outq, p); 415 } 416 else if (!diff_unmodified_pair(p)) 417 /* all the usual ones need to be kept */ 418 diff_q(&outq, p); 419 else 420 /* no need to keep unmodified pairs */ 421 pair_to_free = p; 422 423 if (pair_to_free) 424 diff_free_filepair(pair_to_free); 425 } 426 diff_debug_queue("done copying original", &outq); 427 428 free(q->queue); 429 *q = outq; 430 diff_debug_queue("done collapsing", q); 431 432 /* We need to see which rename source really stays here; 433 * earlier we only checked if the path is left in the result, 434 * but even if a path remains in the result, if that is coming 435 * from copying something else on top of it, then the original 436 * source is lost and does not stay. 437 */ 438 for (i = 0; i < q->nr; i++) { 439 struct diff_filepair *p = q->queue[i]; 440 if (DIFF_PAIR_RENAME(p) && p->source_stays) { 441 /* If one appears as the target of a rename-copy, 442 * then mark p->source_stays = 0; otherwise 443 * leave it as is. 444 */ 445 p->source_stays = compute_stays(q, p->one); 446 } 447 } 448 449 for (i = 0; i < rename_dst_nr; i++) { 450 diff_free_filespec_data(rename_dst[i].two); 451 free(rename_dst[i].two); 452 } 453 454 free(rename_dst); 455 rename_dst = NULL; 456 rename_dst_nr = rename_dst_alloc = 0; 457 free(rename_src); 458 rename_src = NULL; 459 rename_src_nr = rename_src_alloc = 0; 460 return; 461}