diffcore-rename.con commit git-commit: partial commit of paths only removed from the index (db33af0)
   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            !hashcmp(src->sha1, dst->sha1))
 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 (src->sha1_valid && dst->sha1_valid)
 113            return !hashcmp(src->sha1, dst->sha1);
 114        if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
 115                return 0;
 116        if (src->size == dst->size &&
 117            !memcmp(src->data, dst->data, src->size))
 118                return 1;
 119        return 0;
 120}
 121
 122static int basename_same(struct diff_filespec *src, struct diff_filespec *dst)
 123{
 124        int src_len = strlen(src->path), dst_len = strlen(dst->path);
 125        while (src_len && dst_len) {
 126                char c1 = src->path[--src_len];
 127                char c2 = dst->path[--dst_len];
 128                if (c1 != c2)
 129                        return 0;
 130                if (c1 == '/')
 131                        return 1;
 132        }
 133        return (!src_len || src->path[src_len - 1] == '/') &&
 134                (!dst_len || dst->path[dst_len - 1] == '/');
 135}
 136
 137struct diff_score {
 138        int src; /* index in rename_src */
 139        int dst; /* index in rename_dst */
 140        int score;
 141        int name_score;
 142};
 143
 144static int estimate_similarity(struct diff_filespec *src,
 145                               struct diff_filespec *dst,
 146                               int minimum_score)
 147{
 148        /* src points at a file that existed in the original tree (or
 149         * optionally a file in the destination tree) and dst points
 150         * at a newly created file.  They may be quite similar, in which
 151         * case we want to say src is renamed to dst or src is copied into
 152         * dst, and then some edit has been applied to dst.
 153         *
 154         * Compare them and return how similar they are, representing
 155         * the score as an integer between 0 and MAX_SCORE.
 156         *
 157         * When there is an exact match, it is considered a better
 158         * match than anything else; the destination does not even
 159         * call into this function in that case.
 160         */
 161        unsigned long max_size, delta_size, base_size, src_copied, literal_added;
 162        unsigned long delta_limit;
 163        int score;
 164
 165        /* We deal only with regular files.  Symlink renames are handled
 166         * only when they are exact matches --- in other words, no edits
 167         * after renaming.
 168         */
 169        if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
 170                return 0;
 171
 172        max_size = ((src->size > dst->size) ? src->size : dst->size);
 173        base_size = ((src->size < dst->size) ? src->size : dst->size);
 174        delta_size = max_size - base_size;
 175
 176        /* We would not consider edits that change the file size so
 177         * drastically.  delta_size must be smaller than
 178         * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
 179         *
 180         * Note that base_size == 0 case is handled here already
 181         * and the final score computation below would not have a
 182         * divide-by-zero issue.
 183         */
 184        if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
 185                return 0;
 186
 187        if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
 188                return 0; /* error but caught downstream */
 189
 190
 191        delta_limit = (unsigned long)
 192                (base_size * (MAX_SCORE-minimum_score) / MAX_SCORE);
 193        if (diffcore_count_changes(src, dst,
 194                                   &src->cnt_data, &dst->cnt_data,
 195                                   delta_limit,
 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 *one, *two, *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].one;
 218        one = alloc_filespec(src->path);
 219        fill_filespec(one, src->sha1, src->mode);
 220
 221        dst = rename_dst[dst_index].two;
 222        two = alloc_filespec(dst->path);
 223        fill_filespec(two, dst->sha1, dst->mode);
 224
 225        dp = diff_queue(NULL, one, two);
 226        dp->renamed_pair = 1;
 227        if (!strcmp(src->path, dst->path))
 228                dp->score = rename_src[src_index].score;
 229        else
 230                dp->score = score;
 231        dp->source_stays = rename_src[src_index].src_path_left;
 232        rename_dst[dst_index].pair = dp;
 233}
 234
 235/*
 236 * We sort the rename similarity matrix with the score, in descending
 237 * order (the most similar first).
 238 */
 239static int score_compare(const void *a_, const void *b_)
 240{
 241        const struct diff_score *a = a_, *b = b_;
 242
 243        if (a->score == b->score)
 244                return b->name_score - a->name_score;
 245
 246        return b->score - a->score;
 247}
 248
 249static int compute_stays(struct diff_queue_struct *q,
 250                         struct diff_filespec *one)
 251{
 252        int i;
 253        for (i = 0; i < q->nr; i++) {
 254                struct diff_filepair *p = q->queue[i];
 255                if (strcmp(one->path, p->two->path))
 256                        continue;
 257                if (DIFF_PAIR_RENAME(p)) {
 258                        return 0; /* something else is renamed into this */
 259                }
 260        }
 261        return 1;
 262}
 263
 264void diffcore_rename(struct diff_options *options)
 265{
 266        int detect_rename = options->detect_rename;
 267        int minimum_score = options->rename_score;
 268        int rename_limit = options->rename_limit;
 269        struct diff_queue_struct *q = &diff_queued_diff;
 270        struct diff_queue_struct outq;
 271        struct diff_score *mx;
 272        int i, j, rename_count, contents_too;
 273        int num_create, num_src, dst_cnt;
 274
 275        if (!minimum_score)
 276                minimum_score = DEFAULT_RENAME_SCORE;
 277        rename_count = 0;
 278
 279        for (i = 0; i < q->nr; i++) {
 280                struct diff_filepair *p = q->queue[i];
 281                if (!DIFF_FILE_VALID(p->one)) {
 282                        if (!DIFF_FILE_VALID(p->two))
 283                                continue; /* unmerged */
 284                        else if (options->single_follow &&
 285                                 strcmp(options->single_follow, p->two->path))
 286                                continue; /* not interested */
 287                        else
 288                                locate_rename_dst(p->two, 1);
 289                }
 290                else if (!DIFF_FILE_VALID(p->two)) {
 291                        /* If the source is a broken "delete", and
 292                         * they did not really want to get broken,
 293                         * that means the source actually stays.
 294                         */
 295                        int stays = (p->broken_pair && !p->score);
 296                        register_rename_src(p->one, stays, p->score);
 297                }
 298                else if (detect_rename == DIFF_DETECT_COPY)
 299                        register_rename_src(p->one, 1, p->score);
 300        }
 301        if (rename_dst_nr == 0 || rename_src_nr == 0 ||
 302            (0 < rename_limit && rename_limit < rename_dst_nr))
 303                goto cleanup; /* nothing to do */
 304
 305        /* We really want to cull the candidates list early
 306         * with cheap tests in order to avoid doing deltas.
 307         * The first round matches up the up-to-date entries,
 308         * and then during the second round we try to match
 309         * cache-dirty entries as well.
 310         */
 311        for (contents_too = 0; contents_too < 2; contents_too++) {
 312                for (i = 0; i < rename_dst_nr; i++) {
 313                        struct diff_filespec *two = rename_dst[i].two;
 314                        if (rename_dst[i].pair)
 315                                continue; /* dealt with an earlier round */
 316                        for (j = 0; j < rename_src_nr; j++) {
 317                                int k;
 318                                struct diff_filespec *one = rename_src[j].one;
 319                                if (!is_exact_match(one, two, contents_too))
 320                                        continue;
 321
 322                                /* see if there is a basename match, too */
 323                                for (k = j; k < rename_src_nr; k++) {
 324                                        one = rename_src[k].one;
 325                                        if (basename_same(one, two) &&
 326                                                is_exact_match(one, two,
 327                                                        contents_too)) {
 328                                                j = k;
 329                                                break;
 330                                        }
 331                                }
 332
 333                                record_rename_pair(i, j, (int)MAX_SCORE);
 334                                rename_count++;
 335                                break; /* we are done with this entry */
 336                        }
 337                }
 338        }
 339
 340        /* Have we run out the created file pool?  If so we can avoid
 341         * doing the delta matrix altogether.
 342         */
 343        if (rename_count == rename_dst_nr)
 344                goto cleanup;
 345
 346        if (minimum_score == MAX_SCORE)
 347                goto cleanup;
 348
 349        num_create = (rename_dst_nr - rename_count);
 350        num_src = rename_src_nr;
 351        mx = xmalloc(sizeof(*mx) * num_create * num_src);
 352        for (dst_cnt = i = 0; i < rename_dst_nr; i++) {
 353                int base = dst_cnt * num_src;
 354                struct diff_filespec *two = rename_dst[i].two;
 355                if (rename_dst[i].pair)
 356                        continue; /* dealt with exact match already. */
 357                for (j = 0; j < rename_src_nr; j++) {
 358                        struct diff_filespec *one = rename_src[j].one;
 359                        struct diff_score *m = &mx[base+j];
 360                        m->src = j;
 361                        m->dst = i;
 362                        m->score = estimate_similarity(one, two,
 363                                                       minimum_score);
 364                        m->name_score = basename_same(one, two);
 365                        diff_free_filespec_data(one);
 366                }
 367                /* We do not need the text anymore */
 368                diff_free_filespec_data(two);
 369                dst_cnt++;
 370        }
 371        /* cost matrix sorted by most to least similar pair */
 372        qsort(mx, num_create * num_src, sizeof(*mx), score_compare);
 373        for (i = 0; i < num_create * num_src; i++) {
 374                struct diff_rename_dst *dst = &rename_dst[mx[i].dst];
 375                if (dst->pair)
 376                        continue; /* already done, either exact or fuzzy. */
 377                if (mx[i].score < minimum_score)
 378                        break; /* there is no more usable pair. */
 379                record_rename_pair(mx[i].dst, mx[i].src, mx[i].score);
 380                rename_count++;
 381        }
 382        free(mx);
 383
 384 cleanup:
 385        /* At this point, we have found some renames and copies and they
 386         * are recorded in rename_dst.  The original list is still in *q.
 387         */
 388        outq.queue = NULL;
 389        outq.nr = outq.alloc = 0;
 390        for (i = 0; i < q->nr; i++) {
 391                struct diff_filepair *p = q->queue[i];
 392                struct diff_filepair *pair_to_free = NULL;
 393
 394                if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
 395                        /*
 396                         * Creation
 397                         *
 398                         * We would output this create record if it has
 399                         * not been turned into a rename/copy already.
 400                         */
 401                        struct diff_rename_dst *dst =
 402                                locate_rename_dst(p->two, 0);
 403                        if (dst && dst->pair) {
 404                                diff_q(&outq, dst->pair);
 405                                pair_to_free = p;
 406                        }
 407                        else
 408                                /* no matching rename/copy source, so
 409                                 * record this as a creation.
 410                                 */
 411                                diff_q(&outq, p);
 412                }
 413                else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
 414                        /*
 415                         * Deletion
 416                         *
 417                         * We would output this delete record if:
 418                         *
 419                         * (1) this is a broken delete and the counterpart
 420                         *     broken create remains in the output; or
 421                         * (2) this is not a broken delete, and rename_dst
 422                         *     does not have a rename/copy to move p->one->path
 423                         *     out of existence.
 424                         *
 425                         * Otherwise, the counterpart broken create
 426                         * has been turned into a rename-edit; or
 427                         * delete did not have a matching create to
 428                         * begin with.
 429                         */
 430                        if (DIFF_PAIR_BROKEN(p)) {
 431                                /* broken delete */
 432                                struct diff_rename_dst *dst =
 433                                        locate_rename_dst(p->one, 0);
 434                                if (dst && dst->pair)
 435                                        /* counterpart is now rename/copy */
 436                                        pair_to_free = p;
 437                        }
 438                        else {
 439                                for (j = 0; j < rename_dst_nr; j++) {
 440                                        if (!rename_dst[j].pair)
 441                                                continue;
 442                                        if (strcmp(rename_dst[j].pair->
 443                                                   one->path,
 444                                                   p->one->path))
 445                                                continue;
 446                                        break;
 447                                }
 448                                if (j < rename_dst_nr)
 449                                        /* this path remains */
 450                                        pair_to_free = p;
 451                        }
 452
 453                        if (pair_to_free)
 454                                ;
 455                        else
 456                                diff_q(&outq, p);
 457                }
 458                else if (!diff_unmodified_pair(p))
 459                        /* all the usual ones need to be kept */
 460                        diff_q(&outq, p);
 461                else
 462                        /* no need to keep unmodified pairs */
 463                        pair_to_free = p;
 464
 465                if (pair_to_free)
 466                        diff_free_filepair(pair_to_free);
 467        }
 468        diff_debug_queue("done copying original", &outq);
 469
 470        free(q->queue);
 471        *q = outq;
 472        diff_debug_queue("done collapsing", q);
 473
 474        /* We need to see which rename source really stays here;
 475         * earlier we only checked if the path is left in the result,
 476         * but even if a path remains in the result, if that is coming
 477         * from copying something else on top of it, then the original
 478         * source is lost and does not stay.
 479         */
 480        for (i = 0; i < q->nr; i++) {
 481                struct diff_filepair *p = q->queue[i];
 482                if (DIFF_PAIR_RENAME(p) && p->source_stays) {
 483                        /* If one appears as the target of a rename-copy,
 484                         * then mark p->source_stays = 0; otherwise
 485                         * leave it as is.
 486                         */
 487                        p->source_stays = compute_stays(q, p->one);
 488                }
 489        }
 490
 491        for (i = 0; i < rename_dst_nr; i++) {
 492                diff_free_filespec_data(rename_dst[i].two);
 493                free(rename_dst[i].two);
 494        }
 495
 496        free(rename_dst);
 497        rename_dst = NULL;
 498        rename_dst_nr = rename_dst_alloc = 0;
 499        free(rename_src);
 500        rename_src = NULL;
 501        rename_src_nr = rename_src_alloc = 0;
 502        return;
 503}