Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tag: v1.6.0.3
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 652 lines (576 sloc) 17.047 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651
/*
* Copyright (C) 2005 Junio C Hamano
*/
#include "cache.h"
#include "diff.h"
#include "diffcore.h"
#include "hash.h"

/* Table of rename/copy destinations */

static struct diff_rename_dst {
struct diff_filespec *two;
struct diff_filepair *pair;
} *rename_dst;
static int rename_dst_nr, rename_dst_alloc;

static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
int insert_ok)
{
int first, last;

first = 0;
last = rename_dst_nr;
while (last > first) {
int next = (last + first) >> 1;
struct diff_rename_dst *dst = &(rename_dst[next]);
int cmp = strcmp(two->path, dst->two->path);
if (!cmp)
return dst;
if (cmp < 0) {
last = next;
continue;
}
first = next+1;
}
/* not found */
if (!insert_ok)
return NULL;
/* insert to make it at "first" */
if (rename_dst_alloc <= rename_dst_nr) {
rename_dst_alloc = alloc_nr(rename_dst_alloc);
rename_dst = xrealloc(rename_dst,
rename_dst_alloc * sizeof(*rename_dst));
}
rename_dst_nr++;
if (first < rename_dst_nr)
memmove(rename_dst + first + 1, rename_dst + first,
(rename_dst_nr - first - 1) * sizeof(*rename_dst));
rename_dst[first].two = alloc_filespec(two->path);
fill_filespec(rename_dst[first].two, two->sha1, two->mode);
rename_dst[first].pair = NULL;
return &(rename_dst[first]);
}

/* Table of rename/copy src files */
static struct diff_rename_src {
struct diff_filespec *one;
unsigned short score; /* to remember the break score */
} *rename_src;
static int rename_src_nr, rename_src_alloc;

static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
unsigned short score)
{
int first, last;

first = 0;
last = rename_src_nr;
while (last > first) {
int next = (last + first) >> 1;
struct diff_rename_src *src = &(rename_src[next]);
int cmp = strcmp(one->path, src->one->path);
if (!cmp)
return src;
if (cmp < 0) {
last = next;
continue;
}
first = next+1;
}

/* insert to make it at "first" */
if (rename_src_alloc <= rename_src_nr) {
rename_src_alloc = alloc_nr(rename_src_alloc);
rename_src = xrealloc(rename_src,
rename_src_alloc * sizeof(*rename_src));
}
rename_src_nr++;
if (first < rename_src_nr)
memmove(rename_src + first + 1, rename_src + first,
(rename_src_nr - first - 1) * sizeof(*rename_src));
rename_src[first].one = one;
rename_src[first].score = score;
return &(rename_src[first]);
}

static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
{
int src_len = strlen(src->path), dst_len = strlen(dst->path);
while (src_len && dst_len) {
char c1 = src->path[--src_len];
char c2 = dst->path[--dst_len];
if (c1 != c2)
return 0;
if (c1 == '/')
return 1;
}
return (!src_len || src->path[src_len - 1] == '/') &&
(!dst_len || dst->path[dst_len - 1] == '/');
}

struct diff_score {
int src; /* index in rename_src */
int dst; /* index in rename_dst */
unsigned short score;
short name_score;
};

static int estimate_similarity(struct diff_filespec *src,
struct diff_filespec *dst,
int minimum_score)
{
/* src points at a file that existed in the original tree (or
* optionally a file in the destination tree) and dst points
* at a newly created file. They may be quite similar, in which
* case we want to say src is renamed to dst or src is copied into
* dst, and then some edit has been applied to dst.
*
* Compare them and return how similar they are, representing
* the score as an integer between 0 and MAX_SCORE.
*
* When there is an exact match, it is considered a better
* match than anything else; the destination does not even
* call into this function in that case.
*/
unsigned long max_size, delta_size, base_size, src_copied, literal_added;
unsigned long delta_limit;
int score;

/* We deal only with regular files. Symlink renames are handled
* only when they are exact matches --- in other words, no edits
* after renaming.
*/
if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
return 0;

/*
* Need to check that source and destination sizes are
* filled in before comparing them.
*
* If we already have "cnt_data" filled in, we know it's
* all good (avoid checking the size for zero, as that
* is a possible size - we really should have a flag to
* say whether the size is valid or not!)
*/
if (!src->cnt_data && diff_populate_filespec(src, 0))
return 0;
if (!dst->cnt_data && diff_populate_filespec(dst, 0))
return 0;

max_size = ((src->size > dst->size) ? src->size : dst->size);
base_size = ((src->size < dst->size) ? src->size : dst->size);
delta_size = max_size - base_size;

/* We would not consider edits that change the file size so
* drastically. delta_size must be smaller than
* (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
*
* Note that base_size == 0 case is handled here already
* and the final score computation below would not have a
* divide-by-zero issue.
*/
if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
return 0;

delta_limit = (unsigned long)
(base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
if (diffcore_count_changes(src, dst,
&src->cnt_data, &dst->cnt_data,
delta_limit,
&src_copied, &literal_added))
return 0;

/* How similar are they?
* what percentage of material in dst are from source?
*/
if (!dst->size)
score = 0; /* should not happen */
else
score = (int)(src_copied * MAX_SCORE / max_size);
return score;
}

static void record_rename_pair(int dst_index, int src_index, int score)
{
struct diff_filespec *src, *dst;
struct diff_filepair *dp;

if (rename_dst[dst_index].pair)
die("internal error: dst already matched.");

src = rename_src[src_index].one;
src->rename_used++;
src->count++;

dst = rename_dst[dst_index].two;
dst->count++;

dp = diff_queue(NULL, src, dst);
dp->renamed_pair = 1;
if (!strcmp(src->path, dst->path))
dp->score = rename_src[src_index].score;
else
dp->score = score;
rename_dst[dst_index].pair = dp;
}

/*
* We sort the rename similarity matrix with the score, in descending
* order (the most similar first).
*/
static int score_compare(const void *a_, const void *b_)
{
const struct diff_score *a = a_, *b = b_;

/* sink the unused ones to the bottom */
if (a->dst < 0)
return (0 <= b->dst);
else if (b->dst < 0)
return -1;

if (a->score == b->score)
return b->name_score - a->name_score;

return b->score - a->score;
}

struct file_similarity {
int src_dst, index;
struct diff_filespec *filespec;
struct file_similarity *next;
};

static int find_identical_files(struct file_similarity *src,
struct file_similarity *dst)
{
int renames = 0;

/*
* Walk over all the destinations ...
*/
do {
struct diff_filespec *target = dst->filespec;
struct file_similarity *p, *best;
int i = 100, best_score = -1;

/*
* .. to find the best source match
*/
best = NULL;
for (p = src; p; p = p->next) {
int score;
struct diff_filespec *source = p->filespec;

/* False hash collission? */
if (hashcmp(source->sha1, target->sha1))
continue;
/* Non-regular files? If so, the modes must match! */
if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) {
if (source->mode != target->mode)
continue;
}
/* Give higher scores to sources that haven't been used already */
score = !source->rename_used;
score += basename_same(source, target);
if (score > best_score) {
best = p;
best_score = score;
if (score == 2)
break;
}

/* Too many identical alternatives? Pick one */
if (!--i)
break;
}
if (best) {
record_rename_pair(dst->index, best->index, MAX_SCORE);
renames++;
}
} while ((dst = dst->next) != NULL);
return renames;
}

static void free_similarity_list(struct file_similarity *p)
{
while (p) {
struct file_similarity *entry = p;
p = p->next;
free(entry);
}
}

static int find_same_files(void *ptr)
{
int ret;
struct file_similarity *p = ptr;
struct file_similarity *src = NULL, *dst = NULL;

/* Split the hash list up into sources and destinations */
do {
struct file_similarity *entry = p;
p = p->next;
if (entry->src_dst < 0) {
entry->next = src;
src = entry;
} else {
entry->next = dst;
dst = entry;
}
} while (p);

/*
* If we have both sources *and* destinations, see if
* we can match them up
*/
ret = (src && dst) ? find_identical_files(src, dst) : 0;

/* Free the hashes and return the number of renames found */
free_similarity_list(src);
free_similarity_list(dst);
return ret;
}

static unsigned int hash_filespec(struct diff_filespec *filespec)
{
unsigned int hash;
if (!filespec->sha1_valid) {
if (diff_populate_filespec(filespec, 0))
return 0;
hash_sha1_file(filespec->data, filespec->size, "blob", filespec->sha1);
}
memcpy(&hash, filespec->sha1, sizeof(hash));
return hash;
}

static void insert_file_table(struct hash_table *table, int src_dst, int index, struct diff_filespec *filespec)
{
void **pos;
unsigned int hash;
struct file_similarity *entry = xmalloc(sizeof(*entry));

entry->src_dst = src_dst;
entry->index = index;
entry->filespec = filespec;
entry->next = NULL;

hash = hash_filespec(filespec);
pos = insert_hash(hash, entry, table);

/* We already had an entry there? */
if (pos) {
entry->next = *pos;
*pos = entry;
}
}

/*
* Find exact renames first.
*
* The first round matches up the up-to-date entries,
* and then during the second round we try to match
* cache-dirty entries as well.
*/
static int find_exact_renames(void)
{
int i;
struct hash_table file_table;

init_hash(&file_table);
for (i = 0; i < rename_src_nr; i++)
insert_file_table(&file_table, -1, i, rename_src[i].one);

for (i = 0; i < rename_dst_nr; i++)
insert_file_table(&file_table, 1, i, rename_dst[i].two);

/* Find the renames */
i = for_each_hash(&file_table, find_same_files);

/* .. and free the hash data structure */
free_hash(&file_table);

return i;
}

#define NUM_CANDIDATE_PER_DST 4
static void record_if_better(struct diff_score m[], struct diff_score *o)
{
int i, worst;

/* find the worst one */
worst = 0;
for (i = 1; i < NUM_CANDIDATE_PER_DST; i++)
if (score_compare(&m[i], &m[worst]) > 0)
worst = i;

/* is it better than the worst one? */
if (score_compare(&m[worst], o) > 0)
m[worst] = *o;
}

void diffcore_rename(struct diff_options *options)
{
int detect_rename = options->detect_rename;
int minimum_score = options->rename_score;
int rename_limit = options->rename_limit;
struct diff_queue_struct *q = &diff_queued_diff;
struct diff_queue_struct outq;
struct diff_score *mx;
int i, j, rename_count;
int num_create, num_src, dst_cnt;

if (!minimum_score)
minimum_score = DEFAULT_RENAME_SCORE;

for (i = 0; i < q->nr; i++) {
struct diff_filepair *p = q->queue[i];
if (!DIFF_FILE_VALID(p->one)) {
if (!DIFF_FILE_VALID(p->two))
continue; /* unmerged */
else if (options->single_follow &&
strcmp(options->single_follow, p->two->path))
continue; /* not interested */
else
locate_rename_dst(p->two, 1);
}
else if (!DIFF_FILE_VALID(p->two)) {
/*
* If the source is a broken "delete", and
* they did not really want to get broken,
* that means the source actually stays.
* So we increment the "rename_used" score
* by one, to indicate ourselves as a user
*/
if (p->broken_pair && !p->score)
p->one->rename_used++;
register_rename_src(p->one, p->score);
}
else if (detect_rename == DIFF_DETECT_COPY) {
/*
* Increment the "rename_used" score by
* one, to indicate ourselves as a user.
*/
p->one->rename_used++;
register_rename_src(p->one, p->score);
}
}
if (rename_dst_nr == 0 || rename_src_nr == 0)
goto cleanup; /* nothing to do */

/*
* We really want to cull the candidates list early
* with cheap tests in order to avoid doing deltas.
*/
rename_count = find_exact_renames();

/* Did we only want exact renames? */
if (minimum_score == MAX_SCORE)
goto cleanup;

/*
* Calculate how many renames are left (but all the source
* files still remain as options for rename/copies!)
*/
num_create = (rename_dst_nr - rename_count);
num_src = rename_src_nr;

/* All done? */
if (!num_create)
goto cleanup;

/*
* This basically does a test for the rename matrix not
* growing larger than a "rename_limit" square matrix, ie:
*
* num_create * num_src > rename_limit * rename_limit
*
* but handles the potential overflow case specially (and we
* assume at least 32-bit integers)
*/
if (rename_limit <= 0 || rename_limit > 32767)
rename_limit = 32767;
if ((num_create > rename_limit && num_src > rename_limit) ||
(num_create * num_src > rename_limit * rename_limit)) {
if (options->warn_on_too_large_rename)
warning("too many files, skipping inexact rename detection");
goto cleanup;
}

mx = xcalloc(num_create * NUM_CANDIDATE_PER_DST, sizeof(*mx));
for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
struct diff_filespec *two = rename_dst[i].two;
struct diff_score *m;

if (rename_dst[i].pair)
continue; /* dealt with exact match already. */

m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST];
for (j = 0; j < NUM_CANDIDATE_PER_DST; j++)
m[j].dst = -1;

for (j = 0; j < rename_src_nr; j++) {
struct diff_filespec *one = rename_src[j].one;
struct diff_score this_src;
this_src.score = estimate_similarity(one, two,
minimum_score);
this_src.name_score = basename_same(one, two);
this_src.dst = i;
this_src.src = j;
record_if_better(m, &this_src);
diff_free_filespec_blob(one);
}
/* We do not need the text anymore */
diff_free_filespec_blob(two);
dst_cnt++;
}

/* cost matrix sorted by most to least similar pair */
qsort(mx, dst_cnt * NUM_CANDIDATE_PER_DST, sizeof(*mx), score_compare);

for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
struct diff_rename_dst *dst;

if ((mx[i].dst < 0) ||
(mx[i].score < minimum_score))
break; /* there is no more usable pair. */
dst = &rename_dst[mx[i].dst];
if (dst->pair)
continue; /* already done, either exact or fuzzy. */
if (rename_src[mx[i].src].one->rename_used)
continue;
record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
rename_count++;
}

for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
struct diff_rename_dst *dst;

if ((mx[i].dst < 0) ||
(mx[i].score < minimum_score))
break; /* there is no more usable pair. */
dst = &rename_dst[mx[i].dst];
if (dst->pair)
continue; /* already done, either exact or fuzzy. */
record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
rename_count++;
}
free(mx);

 cleanup:
/* At this point, we have found some renames and copies and they
* are recorded in rename_dst. The original list is still in *q.
*/
outq.queue = NULL;
outq.nr = outq.alloc = 0;
for (i = 0; i < q->nr; i++) {
struct diff_filepair *p = q->queue[i];
struct diff_filepair *pair_to_free = NULL;

if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
/*
* Creation
*
* We would output this create record if it has
* not been turned into a rename/copy already.
*/
struct diff_rename_dst *dst =
locate_rename_dst(p->two, 0);
if (dst && dst->pair) {
diff_q(&outq, dst->pair);
pair_to_free = p;
}
else
/* no matching rename/copy source, so
* record this as a creation.
*/
diff_q(&outq, p);
}
else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
/*
* Deletion
*
* We would output this delete record if:
*
* (1) this is a broken delete and the counterpart
* broken create remains in the output; or
* (2) this is not a broken delete, and rename_dst
* does not have a rename/copy to move p->one->path
* out of existence.
*
* Otherwise, the counterpart broken create
* has been turned into a rename-edit; or
* delete did not have a matching create to
* begin with.
*/
if (DIFF_PAIR_BROKEN(p)) {
/* broken delete */
struct diff_rename_dst *dst =
locate_rename_dst(p->one, 0);
if (dst && dst->pair)
/* counterpart is now rename/copy */
pair_to_free = p;
}
else {
if (p->one->rename_used)
/* this path remains */
pair_to_free = p;
}

if (pair_to_free)
;
else
diff_q(&outq, p);
}
else if (!diff_unmodified_pair(p))
/* all the usual ones need to be kept */
diff_q(&outq, p);
else
/* no need to keep unmodified pairs */
pair_to_free = p;

if (pair_to_free)
diff_free_filepair(pair_to_free);
}
diff_debug_queue("done copying original", &outq);

free(q->queue);
*q = outq;
diff_debug_queue("done collapsing", q);

for (i = 0; i < rename_dst_nr; i++)
free_filespec(rename_dst[i].two);

free(rename_dst);
rename_dst = NULL;
rename_dst_nr = rename_dst_alloc = 0;
free(rename_src);
rename_src = NULL;
rename_src_nr = rename_src_alloc = 0;
return;
}
Something went wrong with that request. Please try again.