diffcore-rename.con commit merge: handle --verify-signatures for unborn branch (7488ba3)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "diff.h"
   6#include "diffcore.h"
   7#include "object-store.h"
   8#include "hashmap.h"
   9#include "progress.h"
  10
  11/* Table of rename/copy destinations */
  12
  13static struct diff_rename_dst {
  14        struct diff_filespec *two;
  15        struct diff_filepair *pair;
  16} *rename_dst;
  17static int rename_dst_nr, rename_dst_alloc;
  18
  19static int find_rename_dst(struct diff_filespec *two)
  20{
  21        int first, last;
  22
  23        first = 0;
  24        last = rename_dst_nr;
  25        while (last > first) {
  26                int next = (last + first) >> 1;
  27                struct diff_rename_dst *dst = &(rename_dst[next]);
  28                int cmp = strcmp(two->path, dst->two->path);
  29                if (!cmp)
  30                        return next;
  31                if (cmp < 0) {
  32                        last = next;
  33                        continue;
  34                }
  35                first = next+1;
  36        }
  37        return -first - 1;
  38}
  39
  40static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two)
  41{
  42        int ofs = find_rename_dst(two);
  43        return ofs < 0 ? NULL : &rename_dst[ofs];
  44}
  45
  46/*
  47 * Returns 0 on success, -1 if we found a duplicate.
  48 */
  49static int add_rename_dst(struct diff_filespec *two)
  50{
  51        int first = find_rename_dst(two);
  52
  53        if (first >= 0)
  54                return -1;
  55        first = -first - 1;
  56
  57        /* insert to make it at "first" */
  58        ALLOC_GROW(rename_dst, rename_dst_nr + 1, rename_dst_alloc);
  59        rename_dst_nr++;
  60        if (first < rename_dst_nr)
  61                MOVE_ARRAY(rename_dst + first + 1, rename_dst + first,
  62                           rename_dst_nr - first - 1);
  63        rename_dst[first].two = alloc_filespec(two->path);
  64        fill_filespec(rename_dst[first].two, &two->oid, two->oid_valid,
  65                      two->mode);
  66        rename_dst[first].pair = NULL;
  67        return 0;
  68}
  69
  70/* Table of rename/copy src files */
  71static struct diff_rename_src {
  72        struct diff_filepair *p;
  73        unsigned short score; /* to remember the break score */
  74} *rename_src;
  75static int rename_src_nr, rename_src_alloc;
  76
  77static struct diff_rename_src *register_rename_src(struct diff_filepair *p)
  78{
  79        int first, last;
  80        struct diff_filespec *one = p->one;
  81        unsigned short score = p->score;
  82
  83        first = 0;
  84        last = rename_src_nr;
  85        while (last > first) {
  86                int next = (last + first) >> 1;
  87                struct diff_rename_src *src = &(rename_src[next]);
  88                int cmp = strcmp(one->path, src->p->one->path);
  89                if (!cmp)
  90                        return src;
  91                if (cmp < 0) {
  92                        last = next;
  93                        continue;
  94                }
  95                first = next+1;
  96        }
  97
  98        /* insert to make it at "first" */
  99        ALLOC_GROW(rename_src, rename_src_nr + 1, rename_src_alloc);
 100        rename_src_nr++;
 101        if (first < rename_src_nr)
 102                MOVE_ARRAY(rename_src + first + 1, rename_src + first,
 103                           rename_src_nr - first - 1);
 104        rename_src[first].p = p;
 105        rename_src[first].score = score;
 106        return &(rename_src[first]);
 107}
 108
 109static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
 110{
 111        int src_len = strlen(src->path), dst_len = strlen(dst->path);
 112        while (src_len && dst_len) {
 113                char c1 = src->path[--src_len];
 114                char c2 = dst->path[--dst_len];
 115                if (c1 != c2)
 116                        return 0;
 117                if (c1 == '/')
 118                        return 1;
 119        }
 120        return (!src_len || src->path[src_len - 1] == '/') &&
 121                (!dst_len || dst->path[dst_len - 1] == '/');
 122}
 123
 124struct diff_score {
 125        int src; /* index in rename_src */
 126        int dst; /* index in rename_dst */
 127        unsigned short score;
 128        short name_score;
 129};
 130
 131static int estimate_similarity(struct diff_filespec *src,
 132                               struct diff_filespec *dst,
 133                               int minimum_score)
 134{
 135        /* src points at a file that existed in the original tree (or
 136         * optionally a file in the destination tree) and dst points
 137         * at a newly created file.  They may be quite similar, in which
 138         * case we want to say src is renamed to dst or src is copied into
 139         * dst, and then some edit has been applied to dst.
 140         *
 141         * Compare them and return how similar they are, representing
 142         * the score as an integer between 0 and MAX_SCORE.
 143         *
 144         * When there is an exact match, it is considered a better
 145         * match than anything else; the destination does not even
 146         * call into this function in that case.
 147         */
 148        unsigned long max_size, delta_size, base_size, src_copied, literal_added;
 149        int score;
 150
 151        /* We deal only with regular files.  Symlink renames are handled
 152         * only when they are exact matches --- in other words, no edits
 153         * after renaming.
 154         */
 155        if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
 156                return 0;
 157
 158        /*
 159         * Need to check that source and destination sizes are
 160         * filled in before comparing them.
 161         *
 162         * If we already have "cnt_data" filled in, we know it's
 163         * all good (avoid checking the size for zero, as that
 164         * is a possible size - we really should have a flag to
 165         * say whether the size is valid or not!)
 166         */
 167        if (!src->cnt_data &&
 168            diff_populate_filespec(src, CHECK_SIZE_ONLY))
 169                return 0;
 170        if (!dst->cnt_data &&
 171            diff_populate_filespec(dst, CHECK_SIZE_ONLY))
 172                return 0;
 173
 174        max_size = ((src->size > dst->size) ? src->size : dst->size);
 175        base_size = ((src->size < dst->size) ? src->size : dst->size);
 176        delta_size = max_size - base_size;
 177
 178        /* We would not consider edits that change the file size so
 179         * drastically.  delta_size must be smaller than
 180         * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
 181         *
 182         * Note that base_size == 0 case is handled here already
 183         * and the final score computation below would not have a
 184         * divide-by-zero issue.
 185         */
 186        if (max_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
 187                return 0;
 188
 189        if (!src->cnt_data && diff_populate_filespec(src, 0))
 190                return 0;
 191        if (!dst->cnt_data && diff_populate_filespec(dst, 0))
 192                return 0;
 193
 194        if (diffcore_count_changes(src, dst,
 195                                   &src->cnt_data, &dst->cnt_data,
 196                                   &src_copied, &literal_added))
 197                return 0;
 198
 199        /* How similar are they?
 200         * what percentage of material in dst are from source?
 201         */
 202        if (!dst->size)
 203                score = 0; /* should not happen */
 204        else
 205                score = (int)(src_copied * MAX_SCORE / max_size);
 206        return score;
 207}
 208
 209static void record_rename_pair(int dst_index, int src_index, int score)
 210{
 211        struct diff_filespec *src, *dst;
 212        struct diff_filepair *dp;
 213
 214        if (rename_dst[dst_index].pair)
 215                die("internal error: dst already matched.");
 216
 217        src = rename_src[src_index].p->one;
 218        src->rename_used++;
 219        src->count++;
 220
 221        dst = rename_dst[dst_index].two;
 222        dst->count++;
 223
 224        dp = diff_queue(NULL, src, dst);
 225        dp->renamed_pair = 1;
 226        if (!strcmp(src->path, dst->path))
 227                dp->score = rename_src[src_index].score;
 228        else
 229                dp->score = score;
 230        rename_dst[dst_index].pair = dp;
 231}
 232
 233/*
 234 * We sort the rename similarity matrix with the score, in descending
 235 * order (the most similar first).
 236 */
 237static int score_compare(const void *a_, const void *b_)
 238{
 239        const struct diff_score *a = a_, *b = b_;
 240
 241        /* sink the unused ones to the bottom */
 242        if (a->dst < 0)
 243                return (0 <= b->dst);
 244        else if (b->dst < 0)
 245                return -1;
 246
 247        if (a->score == b->score)
 248                return b->name_score - a->name_score;
 249
 250        return b->score - a->score;
 251}
 252
 253struct file_similarity {
 254        struct hashmap_entry entry;
 255        int index;
 256        struct diff_filespec *filespec;
 257};
 258
 259static unsigned int hash_filespec(struct diff_filespec *filespec)
 260{
 261        if (!filespec->oid_valid) {
 262                if (diff_populate_filespec(filespec, 0))
 263                        return 0;
 264                hash_object_file(filespec->data, filespec->size, "blob",
 265                                 &filespec->oid);
 266        }
 267        return sha1hash(filespec->oid.hash);
 268}
 269
 270static int find_identical_files(struct hashmap *srcs,
 271                                int dst_index,
 272                                struct diff_options *options)
 273{
 274        int renames = 0;
 275
 276        struct diff_filespec *target = rename_dst[dst_index].two;
 277        struct file_similarity *p, *best = NULL;
 278        int i = 100, best_score = -1;
 279
 280        /*
 281         * Find the best source match for specified destination.
 282         */
 283        p = hashmap_get_from_hash(srcs, hash_filespec(target), NULL);
 284        for (; p; p = hashmap_get_next(srcs, p)) {
 285                int score;
 286                struct diff_filespec *source = p->filespec;
 287
 288                /* False hash collision? */
 289                if (oidcmp(&source->oid, &target->oid))
 290                        continue;
 291                /* Non-regular files? If so, the modes must match! */
 292                if (!S_ISREG(source->mode) || !S_ISREG(target->mode)) {
 293                        if (source->mode != target->mode)
 294                                continue;
 295                }
 296                /* Give higher scores to sources that haven't been used already */
 297                score = !source->rename_used;
 298                if (source->rename_used && options->detect_rename != DIFF_DETECT_COPY)
 299                        continue;
 300                score += basename_same(source, target);
 301                if (score > best_score) {
 302                        best = p;
 303                        best_score = score;
 304                        if (score == 2)
 305                                break;
 306                }
 307
 308                /* Too many identical alternatives? Pick one */
 309                if (!--i)
 310                        break;
 311        }
 312        if (best) {
 313                record_rename_pair(dst_index, best->index, MAX_SCORE);
 314                renames++;
 315        }
 316        return renames;
 317}
 318
 319static void insert_file_table(struct hashmap *table, int index, struct diff_filespec *filespec)
 320{
 321        struct file_similarity *entry = xmalloc(sizeof(*entry));
 322
 323        entry->index = index;
 324        entry->filespec = filespec;
 325
 326        hashmap_entry_init(entry, hash_filespec(filespec));
 327        hashmap_add(table, entry);
 328}
 329
 330/*
 331 * Find exact renames first.
 332 *
 333 * The first round matches up the up-to-date entries,
 334 * and then during the second round we try to match
 335 * cache-dirty entries as well.
 336 */
 337static int find_exact_renames(struct diff_options *options)
 338{
 339        int i, renames = 0;
 340        struct hashmap file_table;
 341
 342        /* Add all sources to the hash table in reverse order, because
 343         * later on they will be retrieved in LIFO order.
 344         */
 345        hashmap_init(&file_table, NULL, NULL, rename_src_nr);
 346        for (i = rename_src_nr-1; i >= 0; i--)
 347                insert_file_table(&file_table, i, rename_src[i].p->one);
 348
 349        /* Walk the destinations and find best source match */
 350        for (i = 0; i < rename_dst_nr; i++)
 351                renames += find_identical_files(&file_table, i, options);
 352
 353        /* Free the hash data structure and entries */
 354        hashmap_free(&file_table, 1);
 355
 356        return renames;
 357}
 358
 359#define NUM_CANDIDATE_PER_DST 4
 360static void record_if_better(struct diff_score m[], struct diff_score *o)
 361{
 362        int i, worst;
 363
 364        /* find the worst one */
 365        worst = 0;
 366        for (i = 1; i < NUM_CANDIDATE_PER_DST; i++)
 367                if (score_compare(&m[i], &m[worst]) > 0)
 368                        worst = i;
 369
 370        /* is it better than the worst one? */
 371        if (score_compare(&m[worst], o) > 0)
 372                m[worst] = *o;
 373}
 374
 375/*
 376 * Returns:
 377 * 0 if we are under the limit;
 378 * 1 if we need to disable inexact rename detection;
 379 * 2 if we would be under the limit if we were given -C instead of -C -C.
 380 */
 381static int too_many_rename_candidates(int num_create,
 382                                      struct diff_options *options)
 383{
 384        int rename_limit = options->rename_limit;
 385        int num_src = rename_src_nr;
 386        int i;
 387
 388        options->needed_rename_limit = 0;
 389
 390        /*
 391         * This basically does a test for the rename matrix not
 392         * growing larger than a "rename_limit" square matrix, ie:
 393         *
 394         *    num_create * num_src > rename_limit * rename_limit
 395         */
 396        if (rename_limit <= 0)
 397                rename_limit = 32767;
 398        if ((num_create <= rename_limit || num_src <= rename_limit) &&
 399            ((uint64_t)num_create * (uint64_t)num_src
 400             <= (uint64_t)rename_limit * (uint64_t)rename_limit))
 401                return 0;
 402
 403        options->needed_rename_limit =
 404                num_src > num_create ? num_src : num_create;
 405
 406        /* Are we running under -C -C? */
 407        if (!options->flags.find_copies_harder)
 408                return 1;
 409
 410        /* Would we bust the limit if we were running under -C? */
 411        for (num_src = i = 0; i < rename_src_nr; i++) {
 412                if (diff_unmodified_pair(rename_src[i].p))
 413                        continue;
 414                num_src++;
 415        }
 416        if ((num_create <= rename_limit || num_src <= rename_limit) &&
 417            ((uint64_t)num_create * (uint64_t)num_src
 418             <= (uint64_t)rename_limit * (uint64_t)rename_limit))
 419                return 2;
 420        return 1;
 421}
 422
 423static int find_renames(struct diff_score *mx, int dst_cnt, int minimum_score, int copies)
 424{
 425        int count = 0, i;
 426
 427        for (i = 0; i < dst_cnt * NUM_CANDIDATE_PER_DST; i++) {
 428                struct diff_rename_dst *dst;
 429
 430                if ((mx[i].dst < 0) ||
 431                    (mx[i].score < minimum_score))
 432                        break; /* there is no more usable pair. */
 433                dst = &rename_dst[mx[i].dst];
 434                if (dst->pair)
 435                        continue; /* already done, either exact or fuzzy. */
 436                if (!copies && rename_src[mx[i].src].p->one->rename_used)
 437                        continue;
 438                record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
 439                count++;
 440        }
 441        return count;
 442}
 443
 444void diffcore_rename(struct diff_options *options)
 445{
 446        int detect_rename = options->detect_rename;
 447        int minimum_score = options->rename_score;
 448        struct diff_queue_struct *q = &diff_queued_diff;
 449        struct diff_queue_struct outq;
 450        struct diff_score *mx;
 451        int i, j, rename_count, skip_unmodified = 0;
 452        int num_create, dst_cnt;
 453        struct progress *progress = NULL;
 454
 455        if (!minimum_score)
 456                minimum_score = DEFAULT_RENAME_SCORE;
 457
 458        for (i = 0; i < q->nr; i++) {
 459                struct diff_filepair *p = q->queue[i];
 460                if (!DIFF_FILE_VALID(p->one)) {
 461                        if (!DIFF_FILE_VALID(p->two))
 462                                continue; /* unmerged */
 463                        else if (options->single_follow &&
 464                                 strcmp(options->single_follow, p->two->path))
 465                                continue; /* not interested */
 466                        else if (!options->flags.rename_empty &&
 467                                 is_empty_blob_oid(&p->two->oid))
 468                                continue;
 469                        else if (add_rename_dst(p->two) < 0) {
 470                                warning("skipping rename detection, detected"
 471                                        " duplicate destination '%s'",
 472                                        p->two->path);
 473                                goto cleanup;
 474                        }
 475                }
 476                else if (!options->flags.rename_empty &&
 477                         is_empty_blob_oid(&p->one->oid))
 478                        continue;
 479                else if (!DIFF_PAIR_UNMERGED(p) && !DIFF_FILE_VALID(p->two)) {
 480                        /*
 481                         * If the source is a broken "delete", and
 482                         * they did not really want to get broken,
 483                         * that means the source actually stays.
 484                         * So we increment the "rename_used" score
 485                         * by one, to indicate ourselves as a user
 486                         */
 487                        if (p->broken_pair && !p->score)
 488                                p->one->rename_used++;
 489                        register_rename_src(p);
 490                }
 491                else if (detect_rename == DIFF_DETECT_COPY) {
 492                        /*
 493                         * Increment the "rename_used" score by
 494                         * one, to indicate ourselves as a user.
 495                         */
 496                        p->one->rename_used++;
 497                        register_rename_src(p);
 498                }
 499        }
 500        if (rename_dst_nr == 0 || rename_src_nr == 0)
 501                goto cleanup; /* nothing to do */
 502
 503        /*
 504         * We really want to cull the candidates list early
 505         * with cheap tests in order to avoid doing deltas.
 506         */
 507        rename_count = find_exact_renames(options);
 508
 509        /* Did we only want exact renames? */
 510        if (minimum_score == MAX_SCORE)
 511                goto cleanup;
 512
 513        /*
 514         * Calculate how many renames are left (but all the source
 515         * files still remain as options for rename/copies!)
 516         */
 517        num_create = (rename_dst_nr - rename_count);
 518
 519        /* All done? */
 520        if (!num_create)
 521                goto cleanup;
 522
 523        switch (too_many_rename_candidates(num_create, options)) {
 524        case 1:
 525                goto cleanup;
 526        case 2:
 527                options->degraded_cc_to_c = 1;
 528                skip_unmodified = 1;
 529                break;
 530        default:
 531                break;
 532        }
 533
 534        if (options->show_rename_progress) {
 535                progress = start_delayed_progress(
 536                                _("Performing inexact rename detection"),
 537                                (uint64_t)rename_dst_nr * (uint64_t)rename_src_nr);
 538        }
 539
 540        mx = xcalloc(st_mult(NUM_CANDIDATE_PER_DST, num_create), sizeof(*mx));
 541        for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
 542                struct diff_filespec *two = rename_dst[i].two;
 543                struct diff_score *m;
 544
 545                if (rename_dst[i].pair)
 546                        continue; /* dealt with exact match already. */
 547
 548                m = &mx[dst_cnt * NUM_CANDIDATE_PER_DST];
 549                for (j = 0; j < NUM_CANDIDATE_PER_DST; j++)
 550                        m[j].dst = -1;
 551
 552                for (j = 0; j < rename_src_nr; j++) {
 553                        struct diff_filespec *one = rename_src[j].p->one;
 554                        struct diff_score this_src;
 555
 556                        if (skip_unmodified &&
 557                            diff_unmodified_pair(rename_src[j].p))
 558                                continue;
 559
 560                        this_src.score = estimate_similarity(one, two,
 561                                                             minimum_score);
 562                        this_src.name_score = basename_same(one, two);
 563                        this_src.dst = i;
 564                        this_src.src = j;
 565                        record_if_better(m, &this_src);
 566                        /*
 567                         * Once we run estimate_similarity,
 568                         * We do not need the text anymore.
 569                         */
 570                        diff_free_filespec_blob(one);
 571                        diff_free_filespec_blob(two);
 572                }
 573                dst_cnt++;
 574                display_progress(progress, (uint64_t)(i+1)*(uint64_t)rename_src_nr);
 575        }
 576        stop_progress(&progress);
 577
 578        /* cost matrix sorted by most to least similar pair */
 579        QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare);
 580
 581        rename_count += find_renames(mx, dst_cnt, minimum_score, 0);
 582        if (detect_rename == DIFF_DETECT_COPY)
 583                rename_count += find_renames(mx, dst_cnt, minimum_score, 1);
 584        free(mx);
 585
 586 cleanup:
 587        /* At this point, we have found some renames and copies and they
 588         * are recorded in rename_dst.  The original list is still in *q.
 589         */
 590        DIFF_QUEUE_CLEAR(&outq);
 591        for (i = 0; i < q->nr; i++) {
 592                struct diff_filepair *p = q->queue[i];
 593                struct diff_filepair *pair_to_free = NULL;
 594
 595                if (DIFF_PAIR_UNMERGED(p)) {
 596                        diff_q(&outq, p);
 597                }
 598                else if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
 599                        /*
 600                         * Creation
 601                         *
 602                         * We would output this create record if it has
 603                         * not been turned into a rename/copy already.
 604                         */
 605                        struct diff_rename_dst *dst = locate_rename_dst(p->two);
 606                        if (dst && dst->pair) {
 607                                diff_q(&outq, dst->pair);
 608                                pair_to_free = p;
 609                        }
 610                        else
 611                                /* no matching rename/copy source, so
 612                                 * record this as a creation.
 613                                 */
 614                                diff_q(&outq, p);
 615                }
 616                else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
 617                        /*
 618                         * Deletion
 619                         *
 620                         * We would output this delete record if:
 621                         *
 622                         * (1) this is a broken delete and the counterpart
 623                         *     broken create remains in the output; or
 624                         * (2) this is not a broken delete, and rename_dst
 625                         *     does not have a rename/copy to move p->one->path
 626                         *     out of existence.
 627                         *
 628                         * Otherwise, the counterpart broken create
 629                         * has been turned into a rename-edit; or
 630                         * delete did not have a matching create to
 631                         * begin with.
 632                         */
 633                        if (DIFF_PAIR_BROKEN(p)) {
 634                                /* broken delete */
 635                                struct diff_rename_dst *dst = locate_rename_dst(p->one);
 636                                if (dst && dst->pair)
 637                                        /* counterpart is now rename/copy */
 638                                        pair_to_free = p;
 639                        }
 640                        else {
 641                                if (p->one->rename_used)
 642                                        /* this path remains */
 643                                        pair_to_free = p;
 644                        }
 645
 646                        if (pair_to_free)
 647                                ;
 648                        else
 649                                diff_q(&outq, p);
 650                }
 651                else if (!diff_unmodified_pair(p))
 652                        /* all the usual ones need to be kept */
 653                        diff_q(&outq, p);
 654                else
 655                        /* no need to keep unmodified pairs */
 656                        pair_to_free = p;
 657
 658                if (pair_to_free)
 659                        diff_free_filepair(pair_to_free);
 660        }
 661        diff_debug_queue("done copying original", &outq);
 662
 663        free(q->queue);
 664        *q = outq;
 665        diff_debug_queue("done collapsing", q);
 666
 667        for (i = 0; i < rename_dst_nr; i++)
 668                free_filespec(rename_dst[i].two);
 669
 670        FREE_AND_NULL(rename_dst);
 671        rename_dst_nr = rename_dst_alloc = 0;
 672        FREE_AND_NULL(rename_src);
 673        rename_src_nr = rename_src_alloc = 0;
 674        return;
 675}