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 src_path_left : 1; 58} *rename_src; 59static int rename_src_nr, rename_src_alloc; 60 61static struct diff_rename_src *register_rename_src(struct diff_filespec *one, 62 int src_path_left) 63{ 64 int first, last; 65 66 first = 0; 67 last = rename_src_nr; 68 while (last > first) { 69 int next = (last + first) >> 1; 70 struct diff_rename_src *src = &(rename_src[next]); 71 int cmp = strcmp(one->path, src->one->path); 72 if (!cmp) 73 return src; 74 if (cmp < 0) { 75 last = next; 76 continue; 77 } 78 first = next+1; 79 } 80 81 /* insert to make it at "first" */ 82 if (rename_src_alloc <= rename_src_nr) { 83 rename_src_alloc = alloc_nr(rename_src_alloc); 84 rename_src = xrealloc(rename_src, 85 rename_src_alloc * sizeof(*rename_src)); 86 } 87 rename_src_nr++; 88 if (first < rename_src_nr) 89 memmove(rename_src + first + 1, rename_src + first, 90 (rename_src_nr - first - 1) * sizeof(*rename_src)); 91 rename_src[first].one = one; 92 rename_src[first].src_path_left = src_path_left; 93 return &(rename_src[first]); 94} 95 96static int is_exact_match(struct diff_filespec *src, struct diff_filespec *dst) 97{ 98 if (src->sha1_valid && dst->sha1_valid && 99 !memcmp(src->sha1, dst->sha1, 20)) 100 return 1; 101 if (diff_populate_filespec(src, 1) || diff_populate_filespec(dst, 1)) 102 return 0; 103 if (src->size != dst->size) 104 return 0; 105 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 106 return 0; 107 if (src->size == dst->size && 108 !memcmp(src->data, dst->data, src->size)) 109 return 1; 110 return 0; 111} 112 113struct diff_score { 114 int src; /* index in rename_src */ 115 int dst; /* index in rename_dst */ 116 int score; 117}; 118 119static int estimate_similarity(struct diff_filespec *src, 120 struct diff_filespec *dst, 121 int minimum_score) 122{ 123 /* src points at a file that existed in the original tree (or 124 * optionally a file in the destination tree) and dst points 125 * at a newly created file. They may be quite similar, in which 126 * case we want to say src is renamed to dst or src is copied into 127 * dst, and then some edit has been applied to dst. 128 * 129 * Compare them and return how similar they are, representing 130 * the score as an integer between 0 and MAX_SCORE. 131 * 132 * When there is an exact match, it is considered a better 133 * match than anything else; the destination does not even 134 * call into this function in that case. 135 */ 136 unsigned long max_size, delta_size, base_size, src_copied, literal_added; 137 unsigned long delta_limit; 138 int score; 139 140 /* We deal only with regular files. Symlink renames are handled 141 * only when they are exact matches --- in other words, no edits 142 * after renaming. 143 */ 144 if (!S_ISREG(src->mode) || !S_ISREG(dst->mode)) 145 return 0; 146 147 max_size = ((src->size > dst->size) ? src->size : dst->size); 148 base_size = ((src->size < dst->size) ? src->size : dst->size); 149 delta_size = max_size - base_size; 150 151 /* We would not consider edits that change the file size so 152 * drastically. delta_size must be smaller than 153 * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size). 154 * 155 * Note that base_size == 0 case is handled here already 156 * and the final score computation below would not have a 157 * divide-by-zero issue. 158 */ 159 if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE) 160 return 0; 161 162 if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0)) 163 return 0; /* error but caught downstream */ 164 165 166 delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE; 167 if (diffcore_count_changes(src->data, src->size, 168 dst->data, dst->size, 169 &src->cnt_data, &dst->cnt_data, 170 delta_limit, 171 &src_copied, &literal_added)) 172 return 0; 173 174 /* How similar are they? 175 * what percentage of material in dst are from source? 176 */ 177 if (!dst->size) 178 score = 0; /* should not happen */ 179 else 180 score = src_copied * MAX_SCORE / max_size; 181 return score; 182} 183 184static void record_rename_pair(int dst_index, int src_index, int score) 185{ 186 struct diff_filespec *one, *two, *src, *dst; 187 struct diff_filepair *dp; 188 189 if (rename_dst[dst_index].pair) 190 die("internal error: dst already matched."); 191 192 src = rename_src[src_index].one; 193 one = alloc_filespec(src->path); 194 fill_filespec(one, src->sha1, src->mode); 195 196 dst = rename_dst[dst_index].two; 197 two = alloc_filespec(dst->path); 198 fill_filespec(two, dst->sha1, dst->mode); 199 200 dp = diff_queue(NULL, one, two); 201 dp->score = score; 202 dp->source_stays = rename_src[src_index].src_path_left; 203 rename_dst[dst_index].pair = dp; 204} 205 206/* 207 * We sort the rename similarity matrix with the score, in descending 208 * order (the most similar first). 209 */ 210static int score_compare(const void *a_, const void *b_) 211{ 212 const struct diff_score *a = a_, *b = b_; 213 return b->score - a->score; 214} 215 216static int compute_stays(struct diff_queue_struct *q, 217 struct diff_filespec *one) 218{ 219 int i; 220 for (i = 0; i < q->nr; i++) { 221 struct diff_filepair *p = q->queue[i]; 222 if (strcmp(one->path, p->two->path)) 223 continue; 224 if (DIFF_PAIR_RENAME(p)) { 225 return 0; /* something else is renamed into this */ 226 } 227 } 228 return 1; 229} 230 231void diffcore_rename(struct diff_options *options) 232{ 233 int detect_rename = options->detect_rename; 234 int minimum_score = options->rename_score; 235 int rename_limit = options->rename_limit; 236 struct diff_queue_struct *q = &diff_queued_diff; 237 struct diff_queue_struct outq; 238 struct diff_score *mx; 239 int i, j, rename_count; 240 int num_create, num_src, dst_cnt; 241 242 if (!minimum_score) 243 minimum_score = DEFAULT_RENAME_SCORE; 244 rename_count = 0; 245 246 for (i = 0; i < q->nr; i++) { 247 struct diff_filepair *p = q->queue[i]; 248 if (!DIFF_FILE_VALID(p->one)) 249 if (!DIFF_FILE_VALID(p->two)) 250 continue; /* unmerged */ 251 else 252 locate_rename_dst(p->two, 1); 253 else if (!DIFF_FILE_VALID(p->two)) { 254 /* If the source is a broken "delete", and 255 * they did not really want to get broken, 256 * that means the source actually stays. 257 */ 258 int stays = (p->broken_pair && !p->score); 259 register_rename_src(p->one, stays); 260 } 261 else if (detect_rename == DIFF_DETECT_COPY) 262 register_rename_src(p->one, 1); 263 } 264 if (rename_dst_nr == 0 || rename_src_nr == 0 || 265 (0 < rename_limit && rename_limit < rename_dst_nr)) 266 goto cleanup; /* nothing to do */ 267 268 /* We really want to cull the candidates list early 269 * with cheap tests in order to avoid doing deltas. 270 */ 271 for (i = 0; i < rename_dst_nr; i++) { 272 struct diff_filespec *two = rename_dst[i].two; 273 for (j = 0; j < rename_src_nr; j++) { 274 struct diff_filespec *one = rename_src[j].one; 275 if (!is_exact_match(one, two)) 276 continue; 277 record_rename_pair(i, j, MAX_SCORE); 278 rename_count++; 279 break; /* we are done with this entry */ 280 } 281 } 282 283 /* Have we run out the created file pool? If so we can avoid 284 * doing the delta matrix altogether. 285 */ 286 if (rename_count == rename_dst_nr) 287 goto cleanup; 288 289 if (minimum_score == MAX_SCORE) 290 goto cleanup; 291 292 num_create = (rename_dst_nr - rename_count); 293 num_src = rename_src_nr; 294 mx = xmalloc(sizeof(*mx) * num_create * num_src); 295 for (dst_cnt = i = 0; i < rename_dst_nr; i++) { 296 int base = dst_cnt * num_src; 297 struct diff_filespec *two = rename_dst[i].two; 298 if (rename_dst[i].pair) 299 continue; /* dealt with exact match already. */ 300 for (j = 0; j < rename_src_nr; j++) { 301 struct diff_filespec *one = rename_src[j].one; 302 struct diff_score *m = &mx[base+j]; 303 m->src = j; 304 m->dst = i; 305 m->score = estimate_similarity(one, two, 306 minimum_score); 307 } 308 /* We do not need the text anymore */ 309 diff_free_filespec_data(two); 310 dst_cnt++; 311 } 312 /* cost matrix sorted by most to least similar pair */ 313 qsort(mx, num_create * num_src, sizeof(*mx), score_compare); 314 for (i = 0; i < num_create * num_src; i++) { 315 struct diff_rename_dst *dst = &rename_dst[mx[i].dst]; 316 if (dst->pair) 317 continue; /* already done, either exact or fuzzy. */ 318 if (mx[i].score < minimum_score) 319 break; /* there is no more usable pair. */ 320 record_rename_pair(mx[i].dst, mx[i].src, mx[i].score); 321 rename_count++; 322 } 323 free(mx); 324 325 cleanup: 326 /* At this point, we have found some renames and copies and they 327 * are recorded in rename_dst. The original list is still in *q. 328 */ 329 outq.queue = NULL; 330 outq.nr = outq.alloc = 0; 331 for (i = 0; i < q->nr; i++) { 332 struct diff_filepair *p = q->queue[i]; 333 struct diff_filepair *pair_to_free = NULL; 334 335 if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) { 336 /* 337 * Creation 338 * 339 * We would output this create record if it has 340 * not been turned into a rename/copy already. 341 */ 342 struct diff_rename_dst *dst = 343 locate_rename_dst(p->two, 0); 344 if (dst && dst->pair) { 345 diff_q(&outq, dst->pair); 346 pair_to_free = p; 347 } 348 else 349 /* no matching rename/copy source, so 350 * record this as a creation. 351 */ 352 diff_q(&outq, p); 353 } 354 else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) { 355 /* 356 * Deletion 357 * 358 * We would output this delete record if: 359 * 360 * (1) this is a broken delete and the counterpart 361 * broken create remains in the output; or 362 * (2) this is not a broken delete, and rename_dst 363 * does not have a rename/copy to move p->one->path 364 * out of existence. 365 * 366 * Otherwise, the counterpart broken create 367 * has been turned into a rename-edit; or 368 * delete did not have a matching create to 369 * begin with. 370 */ 371 if (DIFF_PAIR_BROKEN(p)) { 372 /* broken delete */ 373 struct diff_rename_dst *dst = 374 locate_rename_dst(p->one, 0); 375 if (dst && dst->pair) 376 /* counterpart is now rename/copy */ 377 pair_to_free = p; 378 } 379 else { 380 for (j = 0; j < rename_dst_nr; j++) { 381 if (!rename_dst[j].pair) 382 continue; 383 if (strcmp(rename_dst[j].pair-> 384 one->path, 385 p->one->path)) 386 continue; 387 break; 388 } 389 if (j < rename_dst_nr) 390 /* this path remains */ 391 pair_to_free = p; 392 } 393 394 if (pair_to_free) 395 ; 396 else 397 diff_q(&outq, p); 398 } 399 else if (!diff_unmodified_pair(p)) 400 /* all the usual ones need to be kept */ 401 diff_q(&outq, p); 402 else 403 /* no need to keep unmodified pairs */ 404 pair_to_free = p; 405 406 if (pair_to_free) 407 diff_free_filepair(pair_to_free); 408 } 409 diff_debug_queue("done copying original", &outq); 410 411 free(q->queue); 412 *q = outq; 413 diff_debug_queue("done collapsing", q); 414 415 /* We need to see which rename source really stays here; 416 * earlier we only checked if the path is left in the result, 417 * but even if a path remains in the result, if that is coming 418 * from copying something else on top of it, then the original 419 * source is lost and does not stay. 420 */ 421 for (i = 0; i < q->nr; i++) { 422 struct diff_filepair *p = q->queue[i]; 423 if (DIFF_PAIR_RENAME(p) && p->source_stays) { 424 /* If one appears as the target of a rename-copy, 425 * then mark p->source_stays = 0; otherwise 426 * leave it as is. 427 */ 428 p->source_stays = compute_stays(q, p->one); 429 } 430 } 431 432 for (i = 0; i < rename_dst_nr; i++) { 433 diff_free_filespec_data(rename_dst[i].two); 434 free(rename_dst[i].two); 435 } 436 437 free(rename_dst); 438 rename_dst = NULL; 439 rename_dst_nr = rename_dst_alloc = 0; 440 free(rename_src); 441 rename_src = NULL; 442 rename_src_nr = rename_src_alloc = 0; 443 return; 444}