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, struct diff_filespec *dst) 100{ 101 if (src->sha1_valid && dst->sha1_valid && 102 !memcmp(src->sha1, dst->sha1, 20)) 103 return 1; 104 if (diff_populate_filespec(src, 1) || diff_populate_filespec(dst, 1)) 105 return 0; 106 if (src->size != dst->size) 107 return 0; 108 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 109 return 0; 110 if (src->size == dst->size && 111 !memcmp(src->data, dst->data, src->size)) 112 return 1; 113 return 0; 114} 115 116struct diff_score { 117 int src; /* index in rename_src */ 118 int dst; /* index in rename_dst */ 119 int score; 120}; 121 122static int estimate_similarity(struct diff_filespec *src, 123 struct diff_filespec *dst, 124 int minimum_score) 125{ 126 /* src points at a file that existed in the original tree (or 127 * optionally a file in the destination tree) and dst points 128 * at a newly created file. They may be quite similar, in which 129 * case we want to say src is renamed to dst or src is copied into 130 * dst, and then some edit has been applied to dst. 131 * 132 * Compare them and return how similar they are, representing 133 * the score as an integer between 0 and MAX_SCORE. 134 * 135 * When there is an exact match, it is considered a better 136 * match than anything else; the destination does not even 137 * call into this function in that case. 138 */ 139 unsigned long max_size, delta_size, base_size, src_copied, literal_added; 140 unsigned long delta_limit; 141 int score; 142 143 /* We deal only with regular files. Symlink renames are handled 144 * only when they are exact matches --- in other words, no edits 145 * after renaming. 146 */ 147 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode)) 148 return 0; 149 150 max_size = ((src->size > dst->size) ? src->size : dst->size); 151 base_size = ((src->size < dst->size) ? src->size : dst->size); 152 delta_size = max_size - base_size; 153 154 /* We would not consider edits that change the file size so 155 * drastically. delta_size must be smaller than 156 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size). 157 * 158 * Note that base_size == 0 case is handled here already 159 * and the final score computation below would not have a 160 * divide-by-zero issue. 161 */ 162 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) 163 return 0; 164 165 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 166 return 0; /* error but caught downstream */ 167 168 169 delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE; 170 if (diffcore_count_changes(src->data, src->size, 171 dst->data, dst->size, 172 &src->cnt_data, &dst->cnt_data, 173 delta_limit, 174 &src_copied, &literal_added)) 175 return 0; 176 177 /* How similar are they? 178 * what percentage of material in dst are from source? 179 */ 180 if (!dst->size) 181 score = 0; /* should not happen */ 182 else 183 score = src_copied * MAX_SCORE / max_size; 184 return score; 185} 186 187static void record_rename_pair(int dst_index, int src_index, int score) 188{ 189 struct diff_filespec *one, *two, *src, *dst; 190 struct diff_filepair *dp; 191 192 if (rename_dst[dst_index].pair) 193 die("internal error: dst already matched."); 194 195 src = rename_src[src_index].one; 196 one = alloc_filespec(src->path); 197 fill_filespec(one, src->sha1, src->mode); 198 199 dst = rename_dst[dst_index].two; 200 two = alloc_filespec(dst->path); 201 fill_filespec(two, dst->sha1, dst->mode); 202 203 dp = diff_queue(NULL, one, two); 204 if (!strcmp(src->path, dst->path)) 205 dp->score = rename_src[src_index].score; 206 else 207 dp->score = score; 208 dp->source_stays = rename_src[src_index].src_path_left; 209 rename_dst[dst_index].pair = dp; 210} 211 212/* 213 * We sort the rename similarity matrix with the score, in descending 214 * order (the most similar first). 215 */ 216static int score_compare(const void *a_, const void *b_) 217{ 218 const struct diff_score *a = a_, *b = b_; 219 return b->score - a->score; 220} 221 222static int compute_stays(struct diff_queue_struct *q, 223 struct diff_filespec *one) 224{ 225 int i; 226 for (i = 0; i < q->nr; i++) { 227 struct diff_filepair *p = q->queue[i]; 228 if (strcmp(one->path, p->two->path)) 229 continue; 230 if (DIFF_PAIR_RENAME(p)) { 231 return 0; /* something else is renamed into this */ 232 } 233 } 234 return 1; 235} 236 237void diffcore_rename(struct diff_options *options) 238{ 239 int detect_rename = options->detect_rename; 240 int minimum_score = options->rename_score; 241 int rename_limit = options->rename_limit; 242 struct diff_queue_struct *q = &diff_queued_diff; 243 struct diff_queue_struct outq; 244 struct diff_score *mx; 245 int i, j, rename_count; 246 int num_create, num_src, dst_cnt; 247 248 if (!minimum_score) 249 minimum_score = DEFAULT_RENAME_SCORE; 250 rename_count = 0; 251 252 for (i = 0; i < q->nr; i++) { 253 struct diff_filepair *p = q->queue[i]; 254 if (!DIFF_FILE_VALID(p->one)) 255 if (!DIFF_FILE_VALID(p->two)) 256 continue; /* unmerged */ 257 else 258 locate_rename_dst(p->two, 1); 259 else if (!DIFF_FILE_VALID(p->two)) { 260 /* If the source is a broken "delete", and 261 * they did not really want to get broken, 262 * that means the source actually stays. 263 */ 264 int stays = (p->broken_pair && !p->score); 265 register_rename_src(p->one, stays, p->score); 266 } 267 else if (detect_rename == DIFF_DETECT_COPY) 268 register_rename_src(p->one, 1, p->score); 269 } 270 if (rename_dst_nr == 0 || rename_src_nr == 0 || 271 (0 < rename_limit && rename_limit < rename_dst_nr)) 272 goto cleanup; /* nothing to do */ 273 274 /* We really want to cull the candidates list early 275 * with cheap tests in order to avoid doing deltas. 276 */ 277 for (i = 0; i < rename_dst_nr; i++) { 278 struct diff_filespec *two = rename_dst[i].two; 279 for (j = 0; j < rename_src_nr; j++) { 280 struct diff_filespec *one = rename_src[j].one; 281 if (!is_exact_match(one, two)) 282 continue; 283 record_rename_pair(i, j, MAX_SCORE); 284 rename_count++; 285 break; /* we are done with this entry */ 286 } 287 } 288 289 /* Have we run out the created file pool? If so we can avoid 290 * doing the delta matrix altogether. 291 */ 292 if (rename_count == rename_dst_nr) 293 goto cleanup; 294 295 if (minimum_score == MAX_SCORE) 296 goto cleanup; 297 298 num_create = (rename_dst_nr - rename_count); 299 num_src = rename_src_nr; 300 mx = xmalloc(sizeof(*mx) * num_create * num_src); 301 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 302 int base = dst_cnt * num_src; 303 struct diff_filespec *two = rename_dst[i].two; 304 if (rename_dst[i].pair) 305 continue; /* dealt with exact match already. */ 306 for (j = 0; j < rename_src_nr; j++) { 307 struct diff_filespec *one = rename_src[j].one; 308 struct diff_score *m = &mx[base+j]; 309 m->src = j; 310 m->dst = i; 311 m->score = estimate_similarity(one, two, 312 minimum_score); 313 } 314 /* We do not need the text anymore */ 315 diff_free_filespec_data(two); 316 dst_cnt++; 317 } 318 /* cost matrix sorted by most to least similar pair */ 319 qsort(mx, num_create * num_src, sizeof(*mx), score_compare); 320 for (i = 0; i < num_create * num_src; i++) { 321 struct diff_rename_dst *dst = &rename_dst[mx[i].dst]; 322 if (dst->pair) 323 continue; /* already done, either exact or fuzzy. */ 324 if (mx[i].score < minimum_score) 325 break; /* there is no more usable pair. */ 326 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 327 rename_count++; 328 } 329 free(mx); 330 331 cleanup: 332 /* At this point, we have found some renames and copies and they 333 * are recorded in rename_dst. The original list is still in *q. 334 */ 335 outq.queue = NULL; 336 outq.nr = outq.alloc = 0; 337 for (i = 0; i < q->nr; i++) { 338 struct diff_filepair *p = q->queue[i]; 339 struct diff_filepair *pair_to_free = NULL; 340 341 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 342 /* 343 * Creation 344 * 345 * We would output this create record if it has 346 * not been turned into a rename/copy already. 347 */ 348 struct diff_rename_dst *dst = 349 locate_rename_dst(p->two, 0); 350 if (dst && dst->pair) { 351 diff_q(&outq, dst->pair); 352 pair_to_free = p; 353 } 354 else 355 /* no matching rename/copy source, so 356 * record this as a creation. 357 */ 358 diff_q(&outq, p); 359 } 360 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 361 /* 362 * Deletion 363 * 364 * We would output this delete record if: 365 * 366 * (1) this is a broken delete and the counterpart 367 * broken create remains in the output; or 368 * (2) this is not a broken delete, and rename_dst 369 * does not have a rename/copy to move p->one->path 370 * out of existence. 371 * 372 * Otherwise, the counterpart broken create 373 * has been turned into a rename-edit; or 374 * delete did not have a matching create to 375 * begin with. 376 */ 377 if (DIFF_PAIR_BROKEN(p)) { 378 /* broken delete */ 379 struct diff_rename_dst *dst = 380 locate_rename_dst(p->one, 0); 381 if (dst && dst->pair) 382 /* counterpart is now rename/copy */ 383 pair_to_free = p; 384 } 385 else { 386 for (j = 0; j < rename_dst_nr; j++) { 387 if (!rename_dst[j].pair) 388 continue; 389 if (strcmp(rename_dst[j].pair-> 390 one->path, 391 p->one->path)) 392 continue; 393 break; 394 } 395 if (j < rename_dst_nr) 396 /* this path remains */ 397 pair_to_free = p; 398 } 399 400 if (pair_to_free) 401 ; 402 else 403 diff_q(&outq, p); 404 } 405 else if (!diff_unmodified_pair(p)) 406 /* all the usual ones need to be kept */ 407 diff_q(&outq, p); 408 else 409 /* no need to keep unmodified pairs */ 410 pair_to_free = p; 411 412 if (pair_to_free) 413 diff_free_filepair(pair_to_free); 414 } 415 diff_debug_queue("done copying original", &outq); 416 417 free(q->queue); 418 *q = outq; 419 diff_debug_queue("done collapsing", q); 420 421 /* We need to see which rename source really stays here; 422 * earlier we only checked if the path is left in the result, 423 * but even if a path remains in the result, if that is coming 424 * from copying something else on top of it, then the original 425 * source is lost and does not stay. 426 */ 427 for (i = 0; i < q->nr; i++) { 428 struct diff_filepair *p = q->queue[i]; 429 if (DIFF_PAIR_RENAME(p) && p->source_stays) { 430 /* If one appears as the target of a rename-copy, 431 * then mark p->source_stays = 0; otherwise 432 * leave it as is. 433 */ 434 p->source_stays = compute_stays(q, p->one); 435 } 436 } 437 438 for (i = 0; i < rename_dst_nr; i++) { 439 diff_free_filespec_data(rename_dst[i].two); 440 free(rename_dst[i].two); 441 } 442 443 free(rename_dst); 444 rename_dst = NULL; 445 rename_dst_nr = rename_dst_alloc = 0; 446 free(rename_src); 447 rename_src = NULL; 448 rename_src_nr = rename_src_alloc = 0; 449 return; 450}