git.oblomov.eu Git - git/blob - cache-tree.c

   1 #include "cache.h"
   2 #include "lockfile.h"
   3 #include "tree.h"
   4 #include "tree-walk.h"
   5 #include "cache-tree.h"
   6
   7 #ifndef DEBUG
   8 #define DEBUG 0
   9 #endif
  10
  11 struct cache_tree *cache_tree(void)
  12 {
  13         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  14         it->entry_count = -1;
  15         return it;
  16 }
  17
  18 void cache_tree_free(struct cache_tree **it_p)
  19 {
  20         int i;
  21         struct cache_tree *it = *it_p;
  22
  23         if (!it)
  24                 return;
  25         for (i = 0; i < it->subtree_nr; i++)
  26                 if (it->down[i]) {
  27                         cache_tree_free(&it->down[i]->cache_tree);
  28                         free(it->down[i]);
  29                 }
  30         free(it->down);
  31         free(it);
  32         *it_p = NULL;
  33 }
  34
  35 static int subtree_name_cmp(const char *one, int onelen,
  36                             const char *two, int twolen)
  37 {
  38         if (onelen < twolen)
  39                 return -1;
  40         if (twolen < onelen)
  41                 return 1;
  42         return memcmp(one, two, onelen);
  43 }
  44
  45 static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  46 {
  47         struct cache_tree_sub **down = it->down;
  48         int lo, hi;
  49         lo = 0;
  50         hi = it->subtree_nr;
  51         while (lo < hi) {
  52                 int mi = (lo + hi) / 2;
  53                 struct cache_tree_sub *mdl = down[mi];
  54                 int cmp = subtree_name_cmp(path, pathlen,
  55                                            mdl->name, mdl->namelen);
  56                 if (!cmp)
  57                         return mi;
  58                 if (cmp < 0)
  59                         hi = mi;
  60                 else
  61                         lo = mi + 1;
  62         }
  63         return -lo-1;
  64 }
  65
  66 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  67                                            const char *path,
  68                                            int pathlen,
  69                                            int create)
  70 {
  71         struct cache_tree_sub *down;
  72         int pos = subtree_pos(it, path, pathlen);
  73         if (0 <= pos)
  74                 return it->down[pos];
  75         if (!create)
  76                 return NULL;
  77
  78         pos = -pos-1;
  79         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
  80         it->subtree_nr++;
  81
  82         down = xmalloc(sizeof(*down) + pathlen + 1);
  83         down->cache_tree = NULL;
  84         down->namelen = pathlen;
  85         memcpy(down->name, path, pathlen);
  86         down->name[pathlen] = 0;
  87
  88         if (pos < it->subtree_nr)
  89                 memmove(it->down + pos + 1,
  90                         it->down + pos,
  91                         sizeof(down) * (it->subtree_nr - pos - 1));
  92         it->down[pos] = down;
  93         return down;
  94 }
  95
  96 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
  97 {
  98         int pathlen = strlen(path);
  99         return find_subtree(it, path, pathlen, 1);
 100 }
 101
 102 static int do_invalidate_path(struct cache_tree *it, const char *path)
 103 {
 104         /* a/b/c
 105          * ==> invalidate self
 106          * ==> find "a", have it invalidate "b/c"
 107          * a
 108          * ==> invalidate self
 109          * ==> if "a" exists as a subtree, remove it.
 110          */
 111         const char *slash;
 112         int namelen;
 113         struct cache_tree_sub *down;
 114
 115 #if DEBUG
 116         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 117 #endif
 118
 119         if (!it)
 120                 return 0;
 121         slash = strchrnul(path, '/');
 122         namelen = slash - path;
 123         it->entry_count = -1;
 124         if (!*slash) {
 125                 int pos;
 126                 pos = subtree_pos(it, path, namelen);
 127                 if (0 <= pos) {
 128                         cache_tree_free(&it->down[pos]->cache_tree);
 129                         free(it->down[pos]);
 130                         /* 0 1 2 3 4 5
 131                          *       ^     ^subtree_nr = 6
 132                          *       pos
 133                          * move 4 and 5 up one place (2 entries)
 134                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 135                          */
 136                         memmove(it->down+pos, it->down+pos+1,
 137                                 sizeof(struct cache_tree_sub *) *
 138                                 (it->subtree_nr - pos - 1));
 139                         it->subtree_nr--;
 140                 }
 141                 return 1;
 142         }
 143         down = find_subtree(it, path, namelen, 0);
 144         if (down)
 145                 do_invalidate_path(down->cache_tree, slash + 1);
 146         return 1;
 147 }
 148
 149 void cache_tree_invalidate_path(struct index_state *istate, const char *path)
 150 {
 151         if (do_invalidate_path(istate->cache_tree, path))
 152                 istate->cache_changed |= CACHE_TREE_CHANGED;
 153 }
 154
 155 static int verify_cache(struct cache_entry **cache,
 156                         int entries, int flags)
 157 {
 158         int i, funny;
 159         int silent = flags & WRITE_TREE_SILENT;
 160
 161         /* Verify that the tree is merged */
 162         funny = 0;
 163         for (i = 0; i < entries; i++) {
 164                 const struct cache_entry *ce = cache[i];
 165                 if (ce_stage(ce)) {
 166                         if (silent)
 167                                 return -1;
 168                         if (10 < ++funny) {
 169                                 fprintf(stderr, "...\n");
 170                                 break;
 171                         }
 172                         fprintf(stderr, "%s: unmerged (%s)\n",
 173                                 ce->name, sha1_to_hex(ce->sha1));
 174                 }
 175         }
 176         if (funny)
 177                 return -1;
 178
 179         /* Also verify that the cache does not have path and path/file
 180          * at the same time.  At this point we know the cache has only
 181          * stage 0 entries.
 182          */
 183         funny = 0;
 184         for (i = 0; i < entries - 1; i++) {
 185                 /* path/file always comes after path because of the way
 186                  * the cache is sorted.  Also path can appear only once,
 187                  * which means conflicting one would immediately follow.
 188                  */
 189                 const char *this_name = cache[i]->name;
 190                 const char *next_name = cache[i+1]->name;
 191                 int this_len = strlen(this_name);
 192                 if (this_len < strlen(next_name) &&
 193                     strncmp(this_name, next_name, this_len) == 0 &&
 194                     next_name[this_len] == '/') {
 195                         if (10 < ++funny) {
 196                                 fprintf(stderr, "...\n");
 197                                 break;
 198                         }
 199                         fprintf(stderr, "You have both %s and %s\n",
 200                                 this_name, next_name);
 201                 }
 202         }
 203         if (funny)
 204                 return -1;
 205         return 0;
 206 }
 207
 208 static void discard_unused_subtrees(struct cache_tree *it)
 209 {
 210         struct cache_tree_sub **down = it->down;
 211         int nr = it->subtree_nr;
 212         int dst, src;
 213         for (dst = src = 0; src < nr; src++) {
 214                 struct cache_tree_sub *s = down[src];
 215                 if (s->used)
 216                         down[dst++] = s;
 217                 else {
 218                         cache_tree_free(&s->cache_tree);
 219                         free(s);
 220                         it->subtree_nr--;
 221                 }
 222         }
 223 }
 224
 225 int cache_tree_fully_valid(struct cache_tree *it)
 226 {
 227         int i;
 228         if (!it)
 229                 return 0;
 230         if (it->entry_count < 0 || !has_sha1_file(it->sha1))
 231                 return 0;
 232         for (i = 0; i < it->subtree_nr; i++) {
 233                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 234                         return 0;
 235         }
 236         return 1;
 237 }
 238
 239 static int update_one(struct cache_tree *it,
 240                       struct cache_entry **cache,
 241                       int entries,
 242                       const char *base,
 243                       int baselen,
 244                       int *skip_count,
 245                       int flags)
 246 {
 247         struct strbuf buffer;
 248         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 249         int dryrun = flags & WRITE_TREE_DRY_RUN;
 250         int repair = flags & WRITE_TREE_REPAIR;
 251         int to_invalidate = 0;
 252         int i;
 253
 254         assert(!(dryrun && repair));
 255
 256         *skip_count = 0;
 257
 258         if (0 <= it->entry_count && has_sha1_file(it->sha1))
 259                 return it->entry_count;
 260
 261         /*
 262          * We first scan for subtrees and update them; we start by
 263          * marking existing subtrees -- the ones that are unmarked
 264          * should not be in the result.
 265          */
 266         for (i = 0; i < it->subtree_nr; i++)
 267                 it->down[i]->used = 0;
 268
 269         /*
 270          * Find the subtrees and update them.
 271          */
 272         i = 0;
 273         while (i < entries) {
 274                 const struct cache_entry *ce = cache[i];
 275                 struct cache_tree_sub *sub;
 276                 const char *path, *slash;
 277                 int pathlen, sublen, subcnt, subskip;
 278
 279                 path = ce->name;
 280                 pathlen = ce_namelen(ce);
 281                 if (pathlen <= baselen || memcmp(base, path, baselen))
 282                         break; /* at the end of this level */
 283
 284                 slash = strchr(path + baselen, '/');
 285                 if (!slash) {
 286                         i++;
 287                         continue;
 288                 }
 289                 /*
 290                  * a/bbb/c (base = a/, slash = /c)
 291                  * ==>
 292                  * path+baselen = bbb/c, sublen = 3
 293                  */
 294                 sublen = slash - (path + baselen);
 295                 sub = find_subtree(it, path + baselen, sublen, 1);
 296                 if (!sub->cache_tree)
 297                         sub->cache_tree = cache_tree();
 298                 subcnt = update_one(sub->cache_tree,
 299                                     cache + i, entries - i,
 300                                     path,
 301                                     baselen + sublen + 1,
 302                                     &subskip,
 303                                     flags);
 304                 if (subcnt < 0)
 305                         return subcnt;
 306                 if (!subcnt)
 307                         die("index cache-tree records empty sub-tree");
 308                 i += subcnt;
 309                 sub->count = subcnt; /* to be used in the next loop */
 310                 *skip_count += subskip;
 311                 sub->used = 1;
 312         }
 313
 314         discard_unused_subtrees(it);
 315
 316         /*
 317          * Then write out the tree object for this level.
 318          */
 319         strbuf_init(&buffer, 8192);
 320
 321         i = 0;
 322         while (i < entries) {
 323                 const struct cache_entry *ce = cache[i];
 324                 struct cache_tree_sub *sub;
 325                 const char *path, *slash;
 326                 int pathlen, entlen;
 327                 const unsigned char *sha1;
 328                 unsigned mode;
 329                 int expected_missing = 0;
 330
 331                 path = ce->name;
 332                 pathlen = ce_namelen(ce);
 333                 if (pathlen <= baselen || memcmp(base, path, baselen))
 334                         break; /* at the end of this level */
 335
 336                 slash = strchr(path + baselen, '/');
 337                 if (slash) {
 338                         entlen = slash - (path + baselen);
 339                         sub = find_subtree(it, path + baselen, entlen, 0);
 340                         if (!sub)
 341                                 die("cache-tree.c: '%.*s' in '%s' not found",
 342                                     entlen, path + baselen, path);
 343                         i += sub->count;
 344                         sha1 = sub->cache_tree->sha1;
 345                         mode = S_IFDIR;
 346                         if (sub->cache_tree->entry_count < 0) {
 347                                 to_invalidate = 1;
 348                                 expected_missing = 1;
 349                         }
 350                 }
 351                 else {
 352                         sha1 = ce->sha1;
 353                         mode = ce->ce_mode;
 354                         entlen = pathlen - baselen;
 355                         i++;
 356                 }
 357                 if (mode != S_IFGITLINK && !missing_ok && !has_sha1_file(sha1)) {
 358                         strbuf_release(&buffer);
 359                         if (expected_missing)
 360                                 return -1;
 361                         return error("invalid object %06o %s for '%.*s'",
 362                                 mode, sha1_to_hex(sha1), entlen+baselen, path);
 363                 }
 364
 365                 /*
 366                  * CE_REMOVE entries are removed before the index is
 367                  * written to disk. Skip them to remain consistent
 368                  * with the future on-disk index.
 369                  */
 370                 if (ce->ce_flags & CE_REMOVE) {
 371                         *skip_count = *skip_count + 1;
 372                         continue;
 373                 }
 374
 375                 /*
 376                  * CE_INTENT_TO_ADD entries exist on on-disk index but
 377                  * they are not part of generated trees. Invalidate up
 378                  * to root to force cache-tree users to read elsewhere.
 379                  */
 380                 if (ce->ce_flags & CE_INTENT_TO_ADD) {
 381                         to_invalidate = 1;
 382                         continue;
 383                 }
 384
 385                 strbuf_grow(&buffer, entlen + 100);
 386                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 387                 strbuf_add(&buffer, sha1, 20);
 388
 389 #if DEBUG
 390                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 391                         mode, entlen, path + baselen);
 392 #endif
 393         }
 394
 395         if (repair) {
 396                 unsigned char sha1[20];
 397                 hash_sha1_file(buffer.buf, buffer.len, tree_type, sha1);
 398                 if (has_sha1_file(sha1))
 399                         hashcpy(it->sha1, sha1);
 400                 else
 401                         to_invalidate = 1;
 402         } else if (dryrun)
 403                 hash_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1);
 404         else if (write_sha1_file(buffer.buf, buffer.len, tree_type, it->sha1)) {
 405                 strbuf_release(&buffer);
 406                 return -1;
 407         }
 408
 409         strbuf_release(&buffer);
 410         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 411 #if DEBUG
 412         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 413                 it->entry_count, it->subtree_nr,
 414                 sha1_to_hex(it->sha1));
 415 #endif
 416         return i;
 417 }
 418
 419 int cache_tree_update(struct index_state *istate, int flags)
 420 {
 421         struct cache_tree *it = istate->cache_tree;
 422         struct cache_entry **cache = istate->cache;
 423         int entries = istate->cache_nr;
 424         int skip, i = verify_cache(cache, entries, flags);
 425
 426         if (i)
 427                 return i;
 428         i = update_one(it, cache, entries, "", 0, &skip, flags);
 429         if (i < 0)
 430                 return i;
 431         istate->cache_changed |= CACHE_TREE_CHANGED;
 432         return 0;
 433 }
 434
 435 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 436                       const char *path, int pathlen)
 437 {
 438         int i;
 439
 440         /* One "cache-tree" entry consists of the following:
 441          * path (NUL terminated)
 442          * entry_count, subtree_nr ("%d %d\n")
 443          * tree-sha1 (missing if invalid)
 444          * subtree_nr "cache-tree" entries for subtrees.
 445          */
 446         strbuf_grow(buffer, pathlen + 100);
 447         strbuf_add(buffer, path, pathlen);
 448         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 449
 450 #if DEBUG
 451         if (0 <= it->entry_count)
 452                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 453                         pathlen, path, it->entry_count, it->subtree_nr,
 454                         sha1_to_hex(it->sha1));
 455         else
 456                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 457                         pathlen, path, it->subtree_nr);
 458 #endif
 459
 460         if (0 <= it->entry_count) {
 461                 strbuf_add(buffer, it->sha1, 20);
 462         }
 463         for (i = 0; i < it->subtree_nr; i++) {
 464                 struct cache_tree_sub *down = it->down[i];
 465                 if (i) {
 466                         struct cache_tree_sub *prev = it->down[i-1];
 467                         if (subtree_name_cmp(down->name, down->namelen,
 468                                              prev->name, prev->namelen) <= 0)
 469                                 die("fatal - unsorted cache subtree");
 470                 }
 471                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 472         }
 473 }
 474
 475 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 476 {
 477         write_one(sb, root, "", 0);
 478 }
 479
 480 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 481 {
 482         const char *buf = *buffer;
 483         unsigned long size = *size_p;
 484         const char *cp;
 485         char *ep;
 486         struct cache_tree *it;
 487         int i, subtree_nr;
 488
 489         it = NULL;
 490         /* skip name, but make sure name exists */
 491         while (size && *buf) {
 492                 size--;
 493                 buf++;
 494         }
 495         if (!size)
 496                 goto free_return;
 497         buf++; size--;
 498         it = cache_tree();
 499
 500         cp = buf;
 501         it->entry_count = strtol(cp, &ep, 10);
 502         if (cp == ep)
 503                 goto free_return;
 504         cp = ep;
 505         subtree_nr = strtol(cp, &ep, 10);
 506         if (cp == ep)
 507                 goto free_return;
 508         while (size && *buf && *buf != '\n') {
 509                 size--;
 510                 buf++;
 511         }
 512         if (!size)
 513                 goto free_return;
 514         buf++; size--;
 515         if (0 <= it->entry_count) {
 516                 if (size < 20)
 517                         goto free_return;
 518                 hashcpy(it->sha1, (const unsigned char*)buf);
 519                 buf += 20;
 520                 size -= 20;
 521         }
 522
 523 #if DEBUG
 524         if (0 <= it->entry_count)
 525                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 526                         *buffer, it->entry_count, subtree_nr,
 527                         sha1_to_hex(it->sha1));
 528         else
 529                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 530                         *buffer, subtree_nr);
 531 #endif
 532
 533         /*
 534          * Just a heuristic -- we do not add directories that often but
 535          * we do not want to have to extend it immediately when we do,
 536          * hence +2.
 537          */
 538         it->subtree_alloc = subtree_nr + 2;
 539         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 540         for (i = 0; i < subtree_nr; i++) {
 541                 /* read each subtree */
 542                 struct cache_tree *sub;
 543                 struct cache_tree_sub *subtree;
 544                 const char *name = buf;
 545
 546                 sub = read_one(&buf, &size);
 547                 if (!sub)
 548                         goto free_return;
 549                 subtree = cache_tree_sub(it, name);
 550                 subtree->cache_tree = sub;
 551         }
 552         if (subtree_nr != it->subtree_nr)
 553                 die("cache-tree: internal error");
 554         *buffer = buf;
 555         *size_p = size;
 556         return it;
 557
 558  free_return:
 559         cache_tree_free(&it);
 560         return NULL;
 561 }
 562
 563 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 564 {
 565         if (buffer[0])
 566                 return NULL; /* not the whole tree */
 567         return read_one(&buffer, &size);
 568 }
 569
 570 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 571 {
 572         if (!it)
 573                 return NULL;
 574         while (*path) {
 575                 const char *slash;
 576                 struct cache_tree_sub *sub;
 577
 578                 slash = strchrnul(path, '/');
 579                 /*
 580                  * Between path and slash is the name of the subtree
 581                  * to look for.
 582                  */
 583                 sub = find_subtree(it, path, slash - path, 0);
 584                 if (!sub)
 585                         return NULL;
 586                 it = sub->cache_tree;
 587
 588                 path = slash;
 589                 while (*path == '/')
 590                         path++;
 591         }
 592         return it;
 593 }
 594
 595 int write_index_as_tree(unsigned char *sha1, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 596 {
 597         int entries, was_valid, newfd;
 598         struct lock_file *lock_file;
 599
 600         /*
 601          * We can't free this memory, it becomes part of a linked list
 602          * parsed atexit()
 603          */
 604         lock_file = xcalloc(1, sizeof(struct lock_file));
 605
 606         newfd = hold_lock_file_for_update(lock_file, index_path, LOCK_DIE_ON_ERROR);
 607
 608         entries = read_index_from(index_state, index_path);
 609         if (entries < 0)
 610                 return WRITE_TREE_UNREADABLE_INDEX;
 611         if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
 612                 cache_tree_free(&index_state->cache_tree);
 613
 614         if (!index_state->cache_tree)
 615                 index_state->cache_tree = cache_tree();
 616
 617         was_valid = cache_tree_fully_valid(index_state->cache_tree);
 618         if (!was_valid) {
 619                 if (cache_tree_update(index_state, flags) < 0)
 620                         return WRITE_TREE_UNMERGED_INDEX;
 621                 if (0 <= newfd) {
 622                         if (!write_locked_index(index_state, lock_file, COMMIT_LOCK))
 623                                 newfd = -1;
 624                 }
 625                 /* Not being able to write is fine -- we are only interested
 626                  * in updating the cache-tree part, and if the next caller
 627                  * ends up using the old index with unupdated cache-tree part
 628                  * it misses the work we did here, but that is just a
 629                  * performance penalty and not a big deal.
 630                  */
 631         }
 632
 633         if (prefix) {
 634                 struct cache_tree *subtree;
 635                 subtree = cache_tree_find(index_state->cache_tree, prefix);
 636                 if (!subtree)
 637                         return WRITE_TREE_PREFIX_ERROR;
 638                 hashcpy(sha1, subtree->sha1);
 639         }
 640         else
 641                 hashcpy(sha1, index_state->cache_tree->sha1);
 642
 643         if (0 <= newfd)
 644                 rollback_lock_file(lock_file);
 645
 646         return 0;
 647 }
 648
 649 int write_cache_as_tree(unsigned char *sha1, int flags, const char *prefix)
 650 {
 651         return write_index_as_tree(sha1, &the_index, get_index_file(), flags, prefix);
 652 }
 653
 654 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
 655 {
 656         struct tree_desc desc;
 657         struct name_entry entry;
 658         int cnt;
 659
 660         hashcpy(it->sha1, tree->object.sha1);
 661         init_tree_desc(&desc, tree->buffer, tree->size);
 662         cnt = 0;
 663         while (tree_entry(&desc, &entry)) {
 664                 if (!S_ISDIR(entry.mode))
 665                         cnt++;
 666                 else {
 667                         struct cache_tree_sub *sub;
 668                         struct tree *subtree = lookup_tree(entry.sha1);
 669                         if (!subtree->object.parsed)
 670                                 parse_tree(subtree);
 671                         sub = cache_tree_sub(it, entry.path);
 672                         sub->cache_tree = cache_tree();
 673                         prime_cache_tree_rec(sub->cache_tree, subtree);
 674                         cnt += sub->cache_tree->entry_count;
 675                 }
 676         }
 677         it->entry_count = cnt;
 678 }
 679
 680 void prime_cache_tree(struct index_state *istate, struct tree *tree)
 681 {
 682         cache_tree_free(&istate->cache_tree);
 683         istate->cache_tree = cache_tree();
 684         prime_cache_tree_rec(istate->cache_tree, tree);
 685         istate->cache_changed |= CACHE_TREE_CHANGED;
 686 }
 687
 688 /*
 689  * find the cache_tree that corresponds to the current level without
 690  * exploding the full path into textual form.  The root of the
 691  * cache tree is given as "root", and our current level is "info".
 692  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 693  * (2) Otherwise, find the cache_tree that corresponds to one level
 694  *     above us, and find ourselves in there.
 695  */
 696 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 697                                                          struct traverse_info *info)
 698 {
 699         struct cache_tree *our_parent;
 700
 701         if (!info->prev)
 702                 return root;
 703         our_parent = find_cache_tree_from_traversal(root, info->prev);
 704         return cache_tree_find(our_parent, info->name.path);
 705 }
 706
 707 int cache_tree_matches_traversal(struct cache_tree *root,
 708                                  struct name_entry *ent,
 709                                  struct traverse_info *info)
 710 {
 711         struct cache_tree *it;
 712
 713         it = find_cache_tree_from_traversal(root, info);
 714         it = cache_tree_find(it, ent->path);
 715         if (it && it->entry_count > 0 && !hashcmp(ent->sha1, it->sha1))
 716                 return it->entry_count;
 717         return 0;
 718 }
 719
 720 int update_main_cache_tree(int flags)
 721 {
 722         if (!the_index.cache_tree)
 723                 the_index.cache_tree = cache_tree();
 724         return cache_tree_update(&the_index, flags);
 725 }