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 #include "object-store.h"
   7
   8 #ifndef DEBUG
   9 #define DEBUG 0
  10 #endif
  11
  12 struct cache_tree *cache_tree(void)
  13 {
  14         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  15         it->entry_count = -1;
  16         return it;
  17 }
  18
  19 void cache_tree_free(struct cache_tree **it_p)
  20 {
  21         int i;
  22         struct cache_tree *it = *it_p;
  23
  24         if (!it)
  25                 return;
  26         for (i = 0; i < it->subtree_nr; i++)
  27                 if (it->down[i]) {
  28                         cache_tree_free(&it->down[i]->cache_tree);
  29                         free(it->down[i]);
  30                 }
  31         free(it->down);
  32         free(it);
  33         *it_p = NULL;
  34 }
  35
  36 static int subtree_name_cmp(const char *one, int onelen,
  37                             const char *two, int twolen)
  38 {
  39         if (onelen < twolen)
  40                 return -1;
  41         if (twolen < onelen)
  42                 return 1;
  43         return memcmp(one, two, onelen);
  44 }
  45
  46 static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  47 {
  48         struct cache_tree_sub **down = it->down;
  49         int lo, hi;
  50         lo = 0;
  51         hi = it->subtree_nr;
  52         while (lo < hi) {
  53                 int mi = lo + (hi - lo) / 2;
  54                 struct cache_tree_sub *mdl = down[mi];
  55                 int cmp = subtree_name_cmp(path, pathlen,
  56                                            mdl->name, mdl->namelen);
  57                 if (!cmp)
  58                         return mi;
  59                 if (cmp < 0)
  60                         hi = mi;
  61                 else
  62                         lo = mi + 1;
  63         }
  64         return -lo-1;
  65 }
  66
  67 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  68                                            const char *path,
  69                                            int pathlen,
  70                                            int create)
  71 {
  72         struct cache_tree_sub *down;
  73         int pos = subtree_pos(it, path, pathlen);
  74         if (0 <= pos)
  75                 return it->down[pos];
  76         if (!create)
  77                 return NULL;
  78
  79         pos = -pos-1;
  80         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
  81         it->subtree_nr++;
  82
  83         FLEX_ALLOC_MEM(down, name, path, pathlen);
  84         down->cache_tree = NULL;
  85         down->namelen = pathlen;
  86
  87         if (pos < it->subtree_nr)
  88                 MOVE_ARRAY(it->down + pos + 1, it->down + pos,
  89                            it->subtree_nr - pos - 1);
  90         it->down[pos] = down;
  91         return down;
  92 }
  93
  94 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
  95 {
  96         int pathlen = strlen(path);
  97         return find_subtree(it, path, pathlen, 1);
  98 }
  99
 100 static int do_invalidate_path(struct cache_tree *it, const char *path)
 101 {
 102         /* a/b/c
 103          * ==> invalidate self
 104          * ==> find "a", have it invalidate "b/c"
 105          * a
 106          * ==> invalidate self
 107          * ==> if "a" exists as a subtree, remove it.
 108          */
 109         const char *slash;
 110         int namelen;
 111         struct cache_tree_sub *down;
 112
 113 #if DEBUG
 114         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 115 #endif
 116
 117         if (!it)
 118                 return 0;
 119         slash = strchrnul(path, '/');
 120         namelen = slash - path;
 121         it->entry_count = -1;
 122         if (!*slash) {
 123                 int pos;
 124                 pos = subtree_pos(it, path, namelen);
 125                 if (0 <= pos) {
 126                         cache_tree_free(&it->down[pos]->cache_tree);
 127                         free(it->down[pos]);
 128                         /* 0 1 2 3 4 5
 129                          *       ^     ^subtree_nr = 6
 130                          *       pos
 131                          * move 4 and 5 up one place (2 entries)
 132                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 133                          */
 134                         MOVE_ARRAY(it->down + pos, it->down + pos + 1,
 135                                    it->subtree_nr - pos - 1);
 136                         it->subtree_nr--;
 137                 }
 138                 return 1;
 139         }
 140         down = find_subtree(it, path, namelen, 0);
 141         if (down)
 142                 do_invalidate_path(down->cache_tree, slash + 1);
 143         return 1;
 144 }
 145
 146 void cache_tree_invalidate_path(struct index_state *istate, const char *path)
 147 {
 148         if (do_invalidate_path(istate->cache_tree, path))
 149                 istate->cache_changed |= CACHE_TREE_CHANGED;
 150 }
 151
 152 static int verify_cache(struct cache_entry **cache,
 153                         int entries, int flags)
 154 {
 155         int i, funny;
 156         int silent = flags & WRITE_TREE_SILENT;
 157
 158         /* Verify that the tree is merged */
 159         funny = 0;
 160         for (i = 0; i < entries; i++) {
 161                 const struct cache_entry *ce = cache[i];
 162                 if (ce_stage(ce)) {
 163                         if (silent)
 164                                 return -1;
 165                         if (10 < ++funny) {
 166                                 fprintf(stderr, "...\n");
 167                                 break;
 168                         }
 169                         fprintf(stderr, "%s: unmerged (%s)\n",
 170                                 ce->name, oid_to_hex(&ce->oid));
 171                 }
 172         }
 173         if (funny)
 174                 return -1;
 175
 176         /* Also verify that the cache does not have path and path/file
 177          * at the same time.  At this point we know the cache has only
 178          * stage 0 entries.
 179          */
 180         funny = 0;
 181         for (i = 0; i < entries - 1; i++) {
 182                 /* path/file always comes after path because of the way
 183                  * the cache is sorted.  Also path can appear only once,
 184                  * which means conflicting one would immediately follow.
 185                  */
 186                 const char *this_name = cache[i]->name;
 187                 const char *next_name = cache[i+1]->name;
 188                 int this_len = strlen(this_name);
 189                 if (this_len < strlen(next_name) &&
 190                     strncmp(this_name, next_name, this_len) == 0 &&
 191                     next_name[this_len] == '/') {
 192                         if (10 < ++funny) {
 193                                 fprintf(stderr, "...\n");
 194                                 break;
 195                         }
 196                         fprintf(stderr, "You have both %s and %s\n",
 197                                 this_name, next_name);
 198                 }
 199         }
 200         if (funny)
 201                 return -1;
 202         return 0;
 203 }
 204
 205 static void discard_unused_subtrees(struct cache_tree *it)
 206 {
 207         struct cache_tree_sub **down = it->down;
 208         int nr = it->subtree_nr;
 209         int dst, src;
 210         for (dst = src = 0; src < nr; src++) {
 211                 struct cache_tree_sub *s = down[src];
 212                 if (s->used)
 213                         down[dst++] = s;
 214                 else {
 215                         cache_tree_free(&s->cache_tree);
 216                         free(s);
 217                         it->subtree_nr--;
 218                 }
 219         }
 220 }
 221
 222 int cache_tree_fully_valid(struct cache_tree *it)
 223 {
 224         int i;
 225         if (!it)
 226                 return 0;
 227         if (it->entry_count < 0 || !has_sha1_file(it->oid.hash))
 228                 return 0;
 229         for (i = 0; i < it->subtree_nr; i++) {
 230                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 231                         return 0;
 232         }
 233         return 1;
 234 }
 235
 236 static int update_one(struct cache_tree *it,
 237                       struct cache_entry **cache,
 238                       int entries,
 239                       const char *base,
 240                       int baselen,
 241                       int *skip_count,
 242                       int flags)
 243 {
 244         struct strbuf buffer;
 245         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 246         int dryrun = flags & WRITE_TREE_DRY_RUN;
 247         int repair = flags & WRITE_TREE_REPAIR;
 248         int to_invalidate = 0;
 249         int i;
 250
 251         assert(!(dryrun && repair));
 252
 253         *skip_count = 0;
 254
 255         if (0 <= it->entry_count && has_sha1_file(it->oid.hash))
 256                 return it->entry_count;
 257
 258         /*
 259          * We first scan for subtrees and update them; we start by
 260          * marking existing subtrees -- the ones that are unmarked
 261          * should not be in the result.
 262          */
 263         for (i = 0; i < it->subtree_nr; i++)
 264                 it->down[i]->used = 0;
 265
 266         /*
 267          * Find the subtrees and update them.
 268          */
 269         i = 0;
 270         while (i < entries) {
 271                 const struct cache_entry *ce = cache[i];
 272                 struct cache_tree_sub *sub;
 273                 const char *path, *slash;
 274                 int pathlen, sublen, subcnt, subskip;
 275
 276                 path = ce->name;
 277                 pathlen = ce_namelen(ce);
 278                 if (pathlen <= baselen || memcmp(base, path, baselen))
 279                         break; /* at the end of this level */
 280
 281                 slash = strchr(path + baselen, '/');
 282                 if (!slash) {
 283                         i++;
 284                         continue;
 285                 }
 286                 /*
 287                  * a/bbb/c (base = a/, slash = /c)
 288                  * ==>
 289                  * path+baselen = bbb/c, sublen = 3
 290                  */
 291                 sublen = slash - (path + baselen);
 292                 sub = find_subtree(it, path + baselen, sublen, 1);
 293                 if (!sub->cache_tree)
 294                         sub->cache_tree = cache_tree();
 295                 subcnt = update_one(sub->cache_tree,
 296                                     cache + i, entries - i,
 297                                     path,
 298                                     baselen + sublen + 1,
 299                                     &subskip,
 300                                     flags);
 301                 if (subcnt < 0)
 302                         return subcnt;
 303                 if (!subcnt)
 304                         die("index cache-tree records empty sub-tree");
 305                 i += subcnt;
 306                 sub->count = subcnt; /* to be used in the next loop */
 307                 *skip_count += subskip;
 308                 sub->used = 1;
 309         }
 310
 311         discard_unused_subtrees(it);
 312
 313         /*
 314          * Then write out the tree object for this level.
 315          */
 316         strbuf_init(&buffer, 8192);
 317
 318         i = 0;
 319         while (i < entries) {
 320                 const struct cache_entry *ce = cache[i];
 321                 struct cache_tree_sub *sub = NULL;
 322                 const char *path, *slash;
 323                 int pathlen, entlen;
 324                 const struct object_id *oid;
 325                 unsigned mode;
 326                 int expected_missing = 0;
 327                 int contains_ita = 0;
 328
 329                 path = ce->name;
 330                 pathlen = ce_namelen(ce);
 331                 if (pathlen <= baselen || memcmp(base, path, baselen))
 332                         break; /* at the end of this level */
 333
 334                 slash = strchr(path + baselen, '/');
 335                 if (slash) {
 336                         entlen = slash - (path + baselen);
 337                         sub = find_subtree(it, path + baselen, entlen, 0);
 338                         if (!sub)
 339                                 die("cache-tree.c: '%.*s' in '%s' not found",
 340                                     entlen, path + baselen, path);
 341                         i += sub->count;
 342                         oid = &sub->cache_tree->oid;
 343                         mode = S_IFDIR;
 344                         contains_ita = sub->cache_tree->entry_count < 0;
 345                         if (contains_ita) {
 346                                 to_invalidate = 1;
 347                                 expected_missing = 1;
 348                         }
 349                 }
 350                 else {
 351                         oid = &ce->oid;
 352                         mode = ce->ce_mode;
 353                         entlen = pathlen - baselen;
 354                         i++;
 355                 }
 356
 357                 if (is_null_oid(oid) ||
 358                     (mode != S_IFGITLINK && !missing_ok && !has_object_file(oid))) {
 359                         strbuf_release(&buffer);
 360                         if (expected_missing)
 361                                 return -1;
 362                         return error("invalid object %06o %s for '%.*s'",
 363                                 mode, oid_to_hex(oid), entlen+baselen, path);
 364                 }
 365
 366                 /*
 367                  * CE_REMOVE entries are removed before the index is
 368                  * written to disk. Skip them to remain consistent
 369                  * with the future on-disk index.
 370                  */
 371                 if (ce->ce_flags & CE_REMOVE) {
 372                         *skip_count = *skip_count + 1;
 373                         continue;
 374                 }
 375
 376                 /*
 377                  * CE_INTENT_TO_ADD entries exist on on-disk index but
 378                  * they are not part of generated trees. Invalidate up
 379                  * to root to force cache-tree users to read elsewhere.
 380                  */
 381                 if (!sub && ce_intent_to_add(ce)) {
 382                         to_invalidate = 1;
 383                         continue;
 384                 }
 385
 386                 /*
 387                  * "sub" can be an empty tree if all subentries are i-t-a.
 388                  */
 389                 if (contains_ita && is_empty_tree_oid(oid))
 390                         continue;
 391
 392                 strbuf_grow(&buffer, entlen + 100);
 393                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 394                 strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
 395
 396 #if DEBUG
 397                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 398                         mode, entlen, path + baselen);
 399 #endif
 400         }
 401
 402         if (repair) {
 403                 struct object_id oid;
 404                 hash_object_file(buffer.buf, buffer.len, tree_type, &oid);
 405                 if (has_object_file(&oid))
 406                         oidcpy(&it->oid, &oid);
 407                 else
 408                         to_invalidate = 1;
 409         } else if (dryrun) {
 410                 hash_object_file(buffer.buf, buffer.len, tree_type, &it->oid);
 411         } else if (write_object_file(buffer.buf, buffer.len, tree_type,
 412                                      &it->oid)) {
 413                 strbuf_release(&buffer);
 414                 return -1;
 415         }
 416
 417         strbuf_release(&buffer);
 418         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 419 #if DEBUG
 420         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 421                 it->entry_count, it->subtree_nr,
 422                 oid_to_hex(&it->oid));
 423 #endif
 424         return i;
 425 }
 426
 427 int cache_tree_update(struct index_state *istate, int flags)
 428 {
 429         struct cache_tree *it = istate->cache_tree;
 430         struct cache_entry **cache = istate->cache;
 431         int entries = istate->cache_nr;
 432         int skip, i = verify_cache(cache, entries, flags);
 433
 434         if (i)
 435                 return i;
 436         i = update_one(it, cache, entries, "", 0, &skip, flags);
 437         if (i < 0)
 438                 return i;
 439         istate->cache_changed |= CACHE_TREE_CHANGED;
 440         return 0;
 441 }
 442
 443 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 444                       const char *path, int pathlen)
 445 {
 446         int i;
 447
 448         /* One "cache-tree" entry consists of the following:
 449          * path (NUL terminated)
 450          * entry_count, subtree_nr ("%d %d\n")
 451          * tree-sha1 (missing if invalid)
 452          * subtree_nr "cache-tree" entries for subtrees.
 453          */
 454         strbuf_grow(buffer, pathlen + 100);
 455         strbuf_add(buffer, path, pathlen);
 456         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 457
 458 #if DEBUG
 459         if (0 <= it->entry_count)
 460                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 461                         pathlen, path, it->entry_count, it->subtree_nr,
 462                         oid_to_hex(&it->oid));
 463         else
 464                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 465                         pathlen, path, it->subtree_nr);
 466 #endif
 467
 468         if (0 <= it->entry_count) {
 469                 strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
 470         }
 471         for (i = 0; i < it->subtree_nr; i++) {
 472                 struct cache_tree_sub *down = it->down[i];
 473                 if (i) {
 474                         struct cache_tree_sub *prev = it->down[i-1];
 475                         if (subtree_name_cmp(down->name, down->namelen,
 476                                              prev->name, prev->namelen) <= 0)
 477                                 die("fatal - unsorted cache subtree");
 478                 }
 479                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 480         }
 481 }
 482
 483 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 484 {
 485         write_one(sb, root, "", 0);
 486 }
 487
 488 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 489 {
 490         const char *buf = *buffer;
 491         unsigned long size = *size_p;
 492         const char *cp;
 493         char *ep;
 494         struct cache_tree *it;
 495         int i, subtree_nr;
 496         const unsigned rawsz = the_hash_algo->rawsz;
 497
 498         it = NULL;
 499         /* skip name, but make sure name exists */
 500         while (size && *buf) {
 501                 size--;
 502                 buf++;
 503         }
 504         if (!size)
 505                 goto free_return;
 506         buf++; size--;
 507         it = cache_tree();
 508
 509         cp = buf;
 510         it->entry_count = strtol(cp, &ep, 10);
 511         if (cp == ep)
 512                 goto free_return;
 513         cp = ep;
 514         subtree_nr = strtol(cp, &ep, 10);
 515         if (cp == ep)
 516                 goto free_return;
 517         while (size && *buf && *buf != '\n') {
 518                 size--;
 519                 buf++;
 520         }
 521         if (!size)
 522                 goto free_return;
 523         buf++; size--;
 524         if (0 <= it->entry_count) {
 525                 if (size < rawsz)
 526                         goto free_return;
 527                 oidread(&it->oid, (const unsigned char *)buf);
 528                 buf += rawsz;
 529                 size -= rawsz;
 530         }
 531
 532 #if DEBUG
 533         if (0 <= it->entry_count)
 534                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 535                         *buffer, it->entry_count, subtree_nr,
 536                         oid_to_hex(&it->oid));
 537         else
 538                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 539                         *buffer, subtree_nr);
 540 #endif
 541
 542         /*
 543          * Just a heuristic -- we do not add directories that often but
 544          * we do not want to have to extend it immediately when we do,
 545          * hence +2.
 546          */
 547         it->subtree_alloc = subtree_nr + 2;
 548         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 549         for (i = 0; i < subtree_nr; i++) {
 550                 /* read each subtree */
 551                 struct cache_tree *sub;
 552                 struct cache_tree_sub *subtree;
 553                 const char *name = buf;
 554
 555                 sub = read_one(&buf, &size);
 556                 if (!sub)
 557                         goto free_return;
 558                 subtree = cache_tree_sub(it, name);
 559                 subtree->cache_tree = sub;
 560         }
 561         if (subtree_nr != it->subtree_nr)
 562                 die("cache-tree: internal error");
 563         *buffer = buf;
 564         *size_p = size;
 565         return it;
 566
 567  free_return:
 568         cache_tree_free(&it);
 569         return NULL;
 570 }
 571
 572 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 573 {
 574         if (buffer[0])
 575                 return NULL; /* not the whole tree */
 576         return read_one(&buffer, &size);
 577 }
 578
 579 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 580 {
 581         if (!it)
 582                 return NULL;
 583         while (*path) {
 584                 const char *slash;
 585                 struct cache_tree_sub *sub;
 586
 587                 slash = strchrnul(path, '/');
 588                 /*
 589                  * Between path and slash is the name of the subtree
 590                  * to look for.
 591                  */
 592                 sub = find_subtree(it, path, slash - path, 0);
 593                 if (!sub)
 594                         return NULL;
 595                 it = sub->cache_tree;
 596
 597                 path = slash;
 598                 while (*path == '/')
 599                         path++;
 600         }
 601         return it;
 602 }
 603
 604 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 605 {
 606         int entries, was_valid;
 607         struct lock_file lock_file = LOCK_INIT;
 608         int ret = 0;
 609
 610         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 611
 612         entries = read_index_from(index_state, index_path, get_git_dir());
 613         if (entries < 0) {
 614                 ret = WRITE_TREE_UNREADABLE_INDEX;
 615                 goto out;
 616         }
 617         if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
 618                 cache_tree_free(&index_state->cache_tree);
 619
 620         if (!index_state->cache_tree)
 621                 index_state->cache_tree = cache_tree();
 622
 623         was_valid = cache_tree_fully_valid(index_state->cache_tree);
 624         if (!was_valid) {
 625                 if (cache_tree_update(index_state, flags) < 0) {
 626                         ret = WRITE_TREE_UNMERGED_INDEX;
 627                         goto out;
 628                 }
 629                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
 630                 /* Not being able to write is fine -- we are only interested
 631                  * in updating the cache-tree part, and if the next caller
 632                  * ends up using the old index with unupdated cache-tree part
 633                  * it misses the work we did here, but that is just a
 634                  * performance penalty and not a big deal.
 635                  */
 636         }
 637
 638         if (prefix) {
 639                 struct cache_tree *subtree;
 640                 subtree = cache_tree_find(index_state->cache_tree, prefix);
 641                 if (!subtree) {
 642                         ret = WRITE_TREE_PREFIX_ERROR;
 643                         goto out;
 644                 }
 645                 oidcpy(oid, &subtree->oid);
 646         }
 647         else
 648                 oidcpy(oid, &index_state->cache_tree->oid);
 649
 650 out:
 651         rollback_lock_file(&lock_file);
 652         return ret;
 653 }
 654
 655 int write_cache_as_tree(struct object_id *oid, int flags, const char *prefix)
 656 {
 657         return write_index_as_tree(oid, &the_index, get_index_file(), flags, prefix);
 658 }
 659
 660 static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
 661 {
 662         struct tree_desc desc;
 663         struct name_entry entry;
 664         int cnt;
 665
 666         oidcpy(&it->oid, &tree->object.oid);
 667         init_tree_desc(&desc, tree->buffer, tree->size);
 668         cnt = 0;
 669         while (tree_entry(&desc, &entry)) {
 670                 if (!S_ISDIR(entry.mode))
 671                         cnt++;
 672                 else {
 673                         struct cache_tree_sub *sub;
 674                         struct tree *subtree = lookup_tree(entry.oid);
 675                         if (!subtree->object.parsed)
 676                                 parse_tree(subtree);
 677                         sub = cache_tree_sub(it, entry.path);
 678                         sub->cache_tree = cache_tree();
 679                         prime_cache_tree_rec(sub->cache_tree, subtree);
 680                         cnt += sub->cache_tree->entry_count;
 681                 }
 682         }
 683         it->entry_count = cnt;
 684 }
 685
 686 void prime_cache_tree(struct index_state *istate, struct tree *tree)
 687 {
 688         cache_tree_free(&istate->cache_tree);
 689         istate->cache_tree = cache_tree();
 690         prime_cache_tree_rec(istate->cache_tree, tree);
 691         istate->cache_changed |= CACHE_TREE_CHANGED;
 692 }
 693
 694 /*
 695  * find the cache_tree that corresponds to the current level without
 696  * exploding the full path into textual form.  The root of the
 697  * cache tree is given as "root", and our current level is "info".
 698  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 699  * (2) Otherwise, find the cache_tree that corresponds to one level
 700  *     above us, and find ourselves in there.
 701  */
 702 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 703                                                          struct traverse_info *info)
 704 {
 705         struct cache_tree *our_parent;
 706
 707         if (!info->prev)
 708                 return root;
 709         our_parent = find_cache_tree_from_traversal(root, info->prev);
 710         return cache_tree_find(our_parent, info->name.path);
 711 }
 712
 713 int cache_tree_matches_traversal(struct cache_tree *root,
 714                                  struct name_entry *ent,
 715                                  struct traverse_info *info)
 716 {
 717         struct cache_tree *it;
 718
 719         it = find_cache_tree_from_traversal(root, info);
 720         it = cache_tree_find(it, ent->path);
 721         if (it && it->entry_count > 0 && !oidcmp(ent->oid, &it->oid))
 722                 return it->entry_count;
 723         return 0;
 724 }
 725
 726 int update_main_cache_tree(int flags)
 727 {
 728         if (!the_index.cache_tree)
 729                 the_index.cache_tree = cache_tree();
 730         return cache_tree_update(&the_index, flags);
 731 }