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 dp->renamed_pair = 1; 209 if (!strcmp(src->path, dst->path)) 210 dp->score = rename_src[src_index].score; 211 else 212 dp->score = score; 213 dp->source_stays = rename_src[src_index].src_path_left; 214 rename_dst[dst_index].pair = dp; 215} 216 217/* 218 * We sort the rename similarity matrix with the score, in descending 219 * order (the most similar first). 220 */ 221static int score_compare(const void *a_, const void *b_) 222{ 223 const struct diff_score *a = a_, *b = b_; 224 return b->score - a->score; 225} 226 227static int compute_stays(struct diff_queue_struct *q, 228 struct diff_filespec *one) 229{ 230 int i; 231 for (i = 0; i < q->nr; i++) { 232 struct diff_filepair *p = q->queue[i]; 233 if (strcmp(one->path, p->two->path)) 234 continue; 235 if (DIFF_PAIR_RENAME(p)) { 236 return 0; /* something else is renamed into this */ 237 } 238 } 239 return 1; 240} 241 242void diffcore_rename(struct diff_options *options) 243{ 244 int detect_rename = options->detect_rename; 245 int minimum_score = options->rename_score; 246 int rename_limit = options->rename_limit; 247 struct diff_queue_struct *q = &diff_queued_diff; 248 struct diff_queue_struct outq; 249 struct diff_score *mx; 250 int i, j, rename_count, contents_too; 251 int num_create, num_src, dst_cnt; 252 253 if (!minimum_score) 254 minimum_score = DEFAULT_RENAME_SCORE; 255 rename_count = 0; 256 257 for (i = 0; i < q->nr; i++) { 258 struct diff_filepair *p = q->queue[i]; 259 if (!DIFF_FILE_VALID(p->one)) 260 if (!DIFF_FILE_VALID(p->two)) 261 continue; /* unmerged */ 262 else 263 locate_rename_dst(p->two, 1); 264 else if (!DIFF_FILE_VALID(p->two)) { 265 /* If the source is a broken "delete", and 266 * they did not really want to get broken, 267 * that means the source actually stays. 268 */ 269 int stays = (p->broken_pair && !p->score); 270 register_rename_src(p->one, stays, p->score); 271 } 272 else if (detect_rename == DIFF_DETECT_COPY) 273 register_rename_src(p->one, 1, p->score); 274 } 275 if (rename_dst_nr == 0 || rename_src_nr == 0 || 276 (0 < rename_limit && rename_limit < rename_dst_nr)) 277 goto cleanup; /* nothing to do */ 278 279 /* We really want to cull the candidates list early 280 * with cheap tests in order to avoid doing deltas. 281 * The first round matches up the up-to-date entries, 282 * and then during the second round we try to match 283 * cache-dirty entries as well. 284 */ 285 for (contents_too = 0; contents_too < 2; contents_too++) { 286 for (i = 0; i < rename_dst_nr; i++) { 287 struct diff_filespec *two = rename_dst[i].two; 288 if (rename_dst[i].pair) 289 continue; /* dealt with an earlier round */ 290 for (j = 0; j < rename_src_nr; j++) { 291 struct diff_filespec *one = rename_src[j].one; 292 if (!is_exact_match(one, two, contents_too)) 293 continue; 294 record_rename_pair(i, j, MAX_SCORE); 295 rename_count++; 296 break; /* we are done with this entry */ 297 } 298 } 299 } 300 301 /* Have we run out the created file pool? If so we can avoid 302 * doing the delta matrix altogether. 303 */ 304 if (rename_count == rename_dst_nr) 305 goto cleanup; 306 307 if (minimum_score == MAX_SCORE) 308 goto cleanup; 309 310 num_create = (rename_dst_nr - rename_count); 311 num_src = rename_src_nr; 312 mx = xmalloc(sizeof(*mx) * num_create * num_src); 313 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 314 int base = dst_cnt * num_src; 315 struct diff_filespec *two = rename_dst[i].two; 316 if (rename_dst[i].pair) 317 continue; /* dealt with exact match already. */ 318 for (j = 0; j < rename_src_nr; j++) { 319 struct diff_filespec *one = rename_src[j].one; 320 struct diff_score *m = &mx[base+j]; 321 m->src = j; 322 m->dst = i; 323 m->score = estimate_similarity(one, two, 324 minimum_score); 325 } 326 /* We do not need the text anymore */ 327 diff_free_filespec_data(two); 328 dst_cnt++; 329 } 330 /* cost matrix sorted by most to least similar pair */ 331 qsort(mx, num_create * num_src, sizeof(*mx), score_compare); 332 for (i = 0; i < num_create * num_src; i++) { 333 struct diff_rename_dst *dst = &rename_dst[mx[i].dst]; 334 if (dst->pair) 335 continue; /* already done, either exact or fuzzy. */ 336 if (mx[i].score < minimum_score) 337 break; /* there is no more usable pair. */ 338 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 339 rename_count++; 340 } 341 free(mx); 342 343 cleanup: 344 /* At this point, we have found some renames and copies and they 345 * are recorded in rename_dst. The original list is still in *q. 346 */ 347 outq.queue = NULL; 348 outq.nr = outq.alloc = 0; 349 for (i = 0; i < q->nr; i++) { 350 struct diff_filepair *p = q->queue[i]; 351 struct diff_filepair *pair_to_free = NULL; 352 353 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 354 /* 355 * Creation 356 * 357 * We would output this create record if it has 358 * not been turned into a rename/copy already. 359 */ 360 struct diff_rename_dst *dst = 361 locate_rename_dst(p->two, 0); 362 if (dst && dst->pair) { 363 diff_q(&outq, dst->pair); 364 pair_to_free = p; 365 } 366 else 367 /* no matching rename/copy source, so 368 * record this as a creation. 369 */ 370 diff_q(&outq, p); 371 } 372 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 373 /* 374 * Deletion 375 * 376 * We would output this delete record if: 377 * 378 * (1) this is a broken delete and the counterpart 379 * broken create remains in the output; or 380 * (2) this is not a broken delete, and rename_dst 381 * does not have a rename/copy to move p->one->path 382 * out of existence. 383 * 384 * Otherwise, the counterpart broken create 385 * has been turned into a rename-edit; or 386 * delete did not have a matching create to 387 * begin with. 388 */ 389 if (DIFF_PAIR_BROKEN(p)) { 390 /* broken delete */ 391 struct diff_rename_dst *dst = 392 locate_rename_dst(p->one, 0); 393 if (dst && dst->pair) 394 /* counterpart is now rename/copy */ 395 pair_to_free = p; 396 } 397 else { 398 for (j = 0; j < rename_dst_nr; j++) { 399 if (!rename_dst[j].pair) 400 continue; 401 if (strcmp(rename_dst[j].pair-> 402 one->path, 403 p->one->path)) 404 continue; 405 break; 406 } 407 if (j < rename_dst_nr) 408 /* this path remains */ 409 pair_to_free = p; 410 } 411 412 if (pair_to_free) 413 ; 414 else 415 diff_q(&outq, p); 416 } 417 else if (!diff_unmodified_pair(p)) 418 /* all the usual ones need to be kept */ 419 diff_q(&outq, p); 420 else 421 /* no need to keep unmodified pairs */ 422 pair_to_free = p; 423 424 if (pair_to_free) 425 diff_free_filepair(pair_to_free); 426 } 427 diff_debug_queue("done copying original", &outq); 428 429 free(q->queue); 430 *q = outq; 431 diff_debug_queue("done collapsing", q); 432 433 /* We need to see which rename source really stays here; 434 * earlier we only checked if the path is left in the result, 435 * but even if a path remains in the result, if that is coming 436 * from copying something else on top of it, then the original 437 * source is lost and does not stay. 438 */ 439 for (i = 0; i < q->nr; i++) { 440 struct diff_filepair *p = q->queue[i]; 441 if (DIFF_PAIR_RENAME(p) && p->source_stays) { 442 /* If one appears as the target of a rename-copy, 443 * then mark p->source_stays = 0; otherwise 444 * leave it as is. 445 */ 446 p->source_stays = compute_stays(q, p->one); 447 } 448 } 449 450 for (i = 0; i < rename_dst_nr; i++) { 451 diff_free_filespec_data(rename_dst[i].two); 452 free(rename_dst[i].two); 453 } 454 455 free(rename_dst); 456 rename_dst = NULL; 457 rename_dst_nr = rename_dst_alloc = 0; 458 free(rename_src); 459 rename_src = NULL; 460 rename_src_nr = rename_src_alloc = 0; 461 return; 462}