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 #include "replace-object.h"
   8 #include "promisor-remote.h"
   9 #include "sparse-index.h"
  10
  11 #ifndef DEBUG_CACHE_TREE
  12 #define DEBUG_CACHE_TREE 0
  13 #endif
  14
  15 struct cache_tree *cache_tree(void)
  16 {
  17         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  18         it->entry_count = -1;
  19         return it;
  20 }
  21
  22 void cache_tree_free(struct cache_tree **it_p)
  23 {
  24         int i;
  25         struct cache_tree *it = *it_p;
  26
  27         if (!it)
  28                 return;
  29         for (i = 0; i < it->subtree_nr; i++)
  30                 if (it->down[i]) {
  31                         cache_tree_free(&it->down[i]->cache_tree);
  32                         free(it->down[i]);
  33                 }
  34         free(it->down);
  35         free(it);
  36         *it_p = NULL;
  37 }
  38
  39 static int subtree_name_cmp(const char *one, int onelen,
  40                             const char *two, int twolen)
  41 {
  42         if (onelen < twolen)
  43                 return -1;
  44         if (twolen < onelen)
  45                 return 1;
  46         return memcmp(one, two, onelen);
  47 }
  48
  49 int cache_tree_subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  50 {
  51         struct cache_tree_sub **down = it->down;
  52         int lo, hi;
  53         lo = 0;
  54         hi = it->subtree_nr;
  55         while (lo < hi) {
  56                 int mi = lo + (hi - lo) / 2;
  57                 struct cache_tree_sub *mdl = down[mi];
  58                 int cmp = subtree_name_cmp(path, pathlen,
  59                                            mdl->name, mdl->namelen);
  60                 if (!cmp)
  61                         return mi;
  62                 if (cmp < 0)
  63                         hi = mi;
  64                 else
  65                         lo = mi + 1;
  66         }
  67         return -lo-1;
  68 }
  69
  70 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  71                                            const char *path,
  72                                            int pathlen,
  73                                            int create)
  74 {
  75         struct cache_tree_sub *down;
  76         int pos = cache_tree_subtree_pos(it, path, pathlen);
  77         if (0 <= pos)
  78                 return it->down[pos];
  79         if (!create)
  80                 return NULL;
  81
  82         pos = -pos-1;
  83         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
  84         it->subtree_nr++;
  85
  86         FLEX_ALLOC_MEM(down, name, path, pathlen);
  87         down->cache_tree = NULL;
  88         down->namelen = pathlen;
  89
  90         if (pos < it->subtree_nr)
  91                 MOVE_ARRAY(it->down + pos + 1, it->down + pos,
  92                            it->subtree_nr - pos - 1);
  93         it->down[pos] = down;
  94         return down;
  95 }
  96
  97 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
  98 {
  99         int pathlen = strlen(path);
 100         return find_subtree(it, path, pathlen, 1);
 101 }
 102
 103 static int do_invalidate_path(struct cache_tree *it, const char *path)
 104 {
 105         /* a/b/c
 106          * ==> invalidate self
 107          * ==> find "a", have it invalidate "b/c"
 108          * a
 109          * ==> invalidate self
 110          * ==> if "a" exists as a subtree, remove it.
 111          */
 112         const char *slash;
 113         int namelen;
 114         struct cache_tree_sub *down;
 115
 116 #if DEBUG_CACHE_TREE
 117         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 118 #endif
 119
 120         if (!it)
 121                 return 0;
 122         slash = strchrnul(path, '/');
 123         namelen = slash - path;
 124         it->entry_count = -1;
 125         if (!*slash) {
 126                 int pos;
 127                 pos = cache_tree_subtree_pos(it, path, namelen);
 128                 if (0 <= pos) {
 129                         cache_tree_free(&it->down[pos]->cache_tree);
 130                         free(it->down[pos]);
 131                         /* 0 1 2 3 4 5
 132                          *       ^     ^subtree_nr = 6
 133                          *       pos
 134                          * move 4 and 5 up one place (2 entries)
 135                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 136                          */
 137                         MOVE_ARRAY(it->down + pos, it->down + pos + 1,
 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 index_state *istate, int flags)
 156 {
 157         unsigned i, funny;
 158         int silent = flags & WRITE_TREE_SILENT;
 159
 160         /* Verify that the tree is merged */
 161         funny = 0;
 162         for (i = 0; i < istate->cache_nr; i++) {
 163                 const struct cache_entry *ce = istate->cache[i];
 164                 if (ce_stage(ce)) {
 165                         if (silent)
 166                                 return -1;
 167                         if (10 < ++funny) {
 168                                 fprintf(stderr, "...\n");
 169                                 break;
 170                         }
 171                         fprintf(stderr, "%s: unmerged (%s)\n",
 172                                 ce->name, oid_to_hex(&ce->oid));
 173                 }
 174         }
 175         if (funny)
 176                 return -1;
 177
 178         /* Also verify that the cache does not have path and path/file
 179          * at the same time.  At this point we know the cache has only
 180          * stage 0 entries.
 181          */
 182         funny = 0;
 183         for (i = 0; i + 1 < istate->cache_nr; i++) {
 184                 /* path/file always comes after path because of the way
 185                  * the cache is sorted.  Also path can appear only once,
 186                  * which means conflicting one would immediately follow.
 187                  */
 188                 const struct cache_entry *this_ce = istate->cache[i];
 189                 const struct cache_entry *next_ce = istate->cache[i + 1];
 190                 const char *this_name = this_ce->name;
 191                 const char *next_name = next_ce->name;
 192                 int this_len = ce_namelen(this_ce);
 193                 if (this_len < ce_namelen(next_ce) &&
 194                     next_name[this_len] == '/' &&
 195                     strncmp(this_name, next_name, this_len) == 0) {
 196                         if (10 < ++funny) {
 197                                 fprintf(stderr, "...\n");
 198                                 break;
 199                         }
 200                         fprintf(stderr, "You have both %s and %s\n",
 201                                 this_name, next_name);
 202                 }
 203         }
 204         if (funny)
 205                 return -1;
 206         return 0;
 207 }
 208
 209 static void discard_unused_subtrees(struct cache_tree *it)
 210 {
 211         struct cache_tree_sub **down = it->down;
 212         int nr = it->subtree_nr;
 213         int dst, src;
 214         for (dst = src = 0; src < nr; src++) {
 215                 struct cache_tree_sub *s = down[src];
 216                 if (s->used)
 217                         down[dst++] = s;
 218                 else {
 219                         cache_tree_free(&s->cache_tree);
 220                         free(s);
 221                         it->subtree_nr--;
 222                 }
 223         }
 224 }
 225
 226 int cache_tree_fully_valid(struct cache_tree *it)
 227 {
 228         int i;
 229         if (!it)
 230                 return 0;
 231         if (it->entry_count < 0 || !has_object_file(&it->oid))
 232                 return 0;
 233         for (i = 0; i < it->subtree_nr; i++) {
 234                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 235                         return 0;
 236         }
 237         return 1;
 238 }
 239
 240 static int update_one(struct cache_tree *it,
 241                       struct cache_entry **cache,
 242                       int entries,
 243                       const char *base,
 244                       int baselen,
 245                       int *skip_count,
 246                       int flags)
 247 {
 248         struct strbuf buffer;
 249         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 250         int dryrun = flags & WRITE_TREE_DRY_RUN;
 251         int repair = flags & WRITE_TREE_REPAIR;
 252         int to_invalidate = 0;
 253         int i;
 254
 255         assert(!(dryrun && repair));
 256
 257         *skip_count = 0;
 258
 259         if (0 <= it->entry_count && has_object_file(&it->oid))
 260                 return it->entry_count;
 261
 262         /*
 263          * We first scan for subtrees and update them; we start by
 264          * marking existing subtrees -- the ones that are unmarked
 265          * should not be in the result.
 266          */
 267         for (i = 0; i < it->subtree_nr; i++)
 268                 it->down[i]->used = 0;
 269
 270         /*
 271          * Find the subtrees and update them.
 272          */
 273         i = 0;
 274         while (i < entries) {
 275                 const struct cache_entry *ce = cache[i];
 276                 struct cache_tree_sub *sub;
 277                 const char *path, *slash;
 278                 int pathlen, sublen, subcnt, subskip;
 279
 280                 path = ce->name;
 281                 pathlen = ce_namelen(ce);
 282                 if (pathlen <= baselen || memcmp(base, path, baselen))
 283                         break; /* at the end of this level */
 284
 285                 slash = strchr(path + baselen, '/');
 286                 if (!slash) {
 287                         i++;
 288                         continue;
 289                 }
 290                 /*
 291                  * a/bbb/c (base = a/, slash = /c)
 292                  * ==>
 293                  * path+baselen = bbb/c, sublen = 3
 294                  */
 295                 sublen = slash - (path + baselen);
 296                 sub = find_subtree(it, path + baselen, sublen, 1);
 297                 if (!sub->cache_tree)
 298                         sub->cache_tree = cache_tree();
 299                 subcnt = update_one(sub->cache_tree,
 300                                     cache + i, entries - i,
 301                                     path,
 302                                     baselen + sublen + 1,
 303                                     &subskip,
 304                                     flags);
 305                 if (subcnt < 0)
 306                         return subcnt;
 307                 if (!subcnt)
 308                         die("index cache-tree records empty sub-tree");
 309                 i += subcnt;
 310                 sub->count = subcnt; /* to be used in the next loop */
 311                 *skip_count += subskip;
 312                 sub->used = 1;
 313         }
 314
 315         discard_unused_subtrees(it);
 316
 317         /*
 318          * Then write out the tree object for this level.
 319          */
 320         strbuf_init(&buffer, 8192);
 321
 322         i = 0;
 323         while (i < entries) {
 324                 const struct cache_entry *ce = cache[i];
 325                 struct cache_tree_sub *sub = NULL;
 326                 const char *path, *slash;
 327                 int pathlen, entlen;
 328                 const struct object_id *oid;
 329                 unsigned mode;
 330                 int expected_missing = 0;
 331                 int contains_ita = 0;
 332                 int ce_missing_ok;
 333
 334                 path = ce->name;
 335                 pathlen = ce_namelen(ce);
 336                 if (pathlen <= baselen || memcmp(base, path, baselen))
 337                         break; /* at the end of this level */
 338
 339                 slash = strchr(path + baselen, '/');
 340                 if (slash) {
 341                         entlen = slash - (path + baselen);
 342                         sub = find_subtree(it, path + baselen, entlen, 0);
 343                         if (!sub)
 344                                 die("cache-tree.c: '%.*s' in '%s' not found",
 345                                     entlen, path + baselen, path);
 346                         i += sub->count;
 347                         oid = &sub->cache_tree->oid;
 348                         mode = S_IFDIR;
 349                         contains_ita = sub->cache_tree->entry_count < 0;
 350                         if (contains_ita) {
 351                                 to_invalidate = 1;
 352                                 expected_missing = 1;
 353                         }
 354                 }
 355                 else {
 356                         oid = &ce->oid;
 357                         mode = ce->ce_mode;
 358                         entlen = pathlen - baselen;
 359                         i++;
 360                 }
 361
 362                 ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
 363                         (has_promisor_remote() &&
 364                          ce_skip_worktree(ce));
 365                 if (is_null_oid(oid) ||
 366                     (!ce_missing_ok && !has_object_file(oid))) {
 367                         strbuf_release(&buffer);
 368                         if (expected_missing)
 369                                 return -1;
 370                         return error("invalid object %06o %s for '%.*s'",
 371                                 mode, oid_to_hex(oid), entlen+baselen, path);
 372                 }
 373
 374                 /*
 375                  * CE_REMOVE entries are removed before the index is
 376                  * written to disk. Skip them to remain consistent
 377                  * with the future on-disk index.
 378                  */
 379                 if (ce->ce_flags & CE_REMOVE) {
 380                         *skip_count = *skip_count + 1;
 381                         continue;
 382                 }
 383
 384                 /*
 385                  * CE_INTENT_TO_ADD entries exist on on-disk index but
 386                  * they are not part of generated trees. Invalidate up
 387                  * to root to force cache-tree users to read elsewhere.
 388                  */
 389                 if (!sub && ce_intent_to_add(ce)) {
 390                         to_invalidate = 1;
 391                         continue;
 392                 }
 393
 394                 /*
 395                  * "sub" can be an empty tree if all subentries are i-t-a.
 396                  */
 397                 if (contains_ita && is_empty_tree_oid(oid))
 398                         continue;
 399
 400                 strbuf_grow(&buffer, entlen + 100);
 401                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 402                 strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
 403
 404 #if DEBUG_CACHE_TREE
 405                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 406                         mode, entlen, path + baselen);
 407 #endif
 408         }
 409
 410         if (repair) {
 411                 struct object_id oid;
 412                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 413                                  tree_type, &oid);
 414                 if (has_object_file_with_flags(&oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 415                         oidcpy(&it->oid, &oid);
 416                 else
 417                         to_invalidate = 1;
 418         } else if (dryrun) {
 419                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 420                                  tree_type, &it->oid);
 421         } else if (write_object_file(buffer.buf, buffer.len, tree_type,
 422                                      &it->oid)) {
 423                 strbuf_release(&buffer);
 424                 return -1;
 425         }
 426
 427         strbuf_release(&buffer);
 428         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 429 #if DEBUG_CACHE_TREE
 430         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 431                 it->entry_count, it->subtree_nr,
 432                 oid_to_hex(&it->oid));
 433 #endif
 434         return i;
 435 }
 436
 437 int cache_tree_update(struct index_state *istate, int flags)
 438 {
 439         int skip, i;
 440
 441         i = verify_cache(istate, flags);
 442
 443         if (i)
 444                 return i;
 445
 446         ensure_full_index(istate);
 447
 448         if (!istate->cache_tree)
 449                 istate->cache_tree = cache_tree();
 450
 451         trace_performance_enter();
 452         trace2_region_enter("cache_tree", "update", the_repository);
 453         i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
 454                        "", 0, &skip, flags);
 455         trace2_region_leave("cache_tree", "update", the_repository);
 456         trace_performance_leave("cache_tree_update");
 457         if (i < 0)
 458                 return i;
 459         istate->cache_changed |= CACHE_TREE_CHANGED;
 460         return 0;
 461 }
 462
 463 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 464                       const char *path, int pathlen)
 465 {
 466         int i;
 467
 468         /* One "cache-tree" entry consists of the following:
 469          * path (NUL terminated)
 470          * entry_count, subtree_nr ("%d %d\n")
 471          * tree-sha1 (missing if invalid)
 472          * subtree_nr "cache-tree" entries for subtrees.
 473          */
 474         strbuf_grow(buffer, pathlen + 100);
 475         strbuf_add(buffer, path, pathlen);
 476         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 477
 478 #if DEBUG_CACHE_TREE
 479         if (0 <= it->entry_count)
 480                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 481                         pathlen, path, it->entry_count, it->subtree_nr,
 482                         oid_to_hex(&it->oid));
 483         else
 484                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 485                         pathlen, path, it->subtree_nr);
 486 #endif
 487
 488         if (0 <= it->entry_count) {
 489                 strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
 490         }
 491         for (i = 0; i < it->subtree_nr; i++) {
 492                 struct cache_tree_sub *down = it->down[i];
 493                 if (i) {
 494                         struct cache_tree_sub *prev = it->down[i-1];
 495                         if (subtree_name_cmp(down->name, down->namelen,
 496                                              prev->name, prev->namelen) <= 0)
 497                                 die("fatal - unsorted cache subtree");
 498                 }
 499                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 500         }
 501 }
 502
 503 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 504 {
 505         trace2_region_enter("cache_tree", "write", the_repository);
 506         write_one(sb, root, "", 0);
 507         trace2_region_leave("cache_tree", "write", the_repository);
 508 }
 509
 510 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 511 {
 512         const char *buf = *buffer;
 513         unsigned long size = *size_p;
 514         const char *cp;
 515         char *ep;
 516         struct cache_tree *it;
 517         int i, subtree_nr;
 518         const unsigned rawsz = the_hash_algo->rawsz;
 519
 520         it = NULL;
 521         /* skip name, but make sure name exists */
 522         while (size && *buf) {
 523                 size--;
 524                 buf++;
 525         }
 526         if (!size)
 527                 goto free_return;
 528         buf++; size--;
 529         it = cache_tree();
 530
 531         cp = buf;
 532         it->entry_count = strtol(cp, &ep, 10);
 533         if (cp == ep)
 534                 goto free_return;
 535         cp = ep;
 536         subtree_nr = strtol(cp, &ep, 10);
 537         if (cp == ep)
 538                 goto free_return;
 539         while (size && *buf && *buf != '\n') {
 540                 size--;
 541                 buf++;
 542         }
 543         if (!size)
 544                 goto free_return;
 545         buf++; size--;
 546         if (0 <= it->entry_count) {
 547                 if (size < rawsz)
 548                         goto free_return;
 549                 oidread(&it->oid, (const unsigned char *)buf);
 550                 buf += rawsz;
 551                 size -= rawsz;
 552         }
 553
 554 #if DEBUG_CACHE_TREE
 555         if (0 <= it->entry_count)
 556                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 557                         *buffer, it->entry_count, subtree_nr,
 558                         oid_to_hex(&it->oid));
 559         else
 560                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 561                         *buffer, subtree_nr);
 562 #endif
 563
 564         /*
 565          * Just a heuristic -- we do not add directories that often but
 566          * we do not want to have to extend it immediately when we do,
 567          * hence +2.
 568          */
 569         it->subtree_alloc = subtree_nr + 2;
 570         it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
 571         for (i = 0; i < subtree_nr; i++) {
 572                 /* read each subtree */
 573                 struct cache_tree *sub;
 574                 struct cache_tree_sub *subtree;
 575                 const char *name = buf;
 576
 577                 sub = read_one(&buf, &size);
 578                 if (!sub)
 579                         goto free_return;
 580                 subtree = cache_tree_sub(it, name);
 581                 subtree->cache_tree = sub;
 582         }
 583         if (subtree_nr != it->subtree_nr)
 584                 die("cache-tree: internal error");
 585         *buffer = buf;
 586         *size_p = size;
 587         return it;
 588
 589  free_return:
 590         cache_tree_free(&it);
 591         return NULL;
 592 }
 593
 594 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 595 {
 596         struct cache_tree *result;
 597
 598         if (buffer[0])
 599                 return NULL; /* not the whole tree */
 600
 601         trace2_region_enter("cache_tree", "read", the_repository);
 602         result = read_one(&buffer, &size);
 603         trace2_region_leave("cache_tree", "read", the_repository);
 604
 605         return result;
 606 }
 607
 608 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 609 {
 610         if (!it)
 611                 return NULL;
 612         while (*path) {
 613                 const char *slash;
 614                 struct cache_tree_sub *sub;
 615
 616                 slash = strchrnul(path, '/');
 617                 /*
 618                  * Between path and slash is the name of the subtree
 619                  * to look for.
 620                  */
 621                 sub = find_subtree(it, path, slash - path, 0);
 622                 if (!sub)
 623                         return NULL;
 624                 it = sub->cache_tree;
 625
 626                 path = slash;
 627                 while (*path == '/')
 628                         path++;
 629         }
 630         return it;
 631 }
 632
 633 static int write_index_as_tree_internal(struct object_id *oid,
 634                                         struct index_state *index_state,
 635                                         int cache_tree_valid,
 636                                         int flags,
 637                                         const char *prefix)
 638 {
 639         if (flags & WRITE_TREE_IGNORE_CACHE_TREE) {
 640                 cache_tree_free(&index_state->cache_tree);
 641                 cache_tree_valid = 0;
 642         }
 643
 644         if (!cache_tree_valid && cache_tree_update(index_state, flags) < 0)
 645                 return WRITE_TREE_UNMERGED_INDEX;
 646
 647         if (prefix) {
 648                 struct cache_tree *subtree;
 649                 subtree = cache_tree_find(index_state->cache_tree, prefix);
 650                 if (!subtree)
 651                         return WRITE_TREE_PREFIX_ERROR;
 652                 oidcpy(oid, &subtree->oid);
 653         }
 654         else
 655                 oidcpy(oid, &index_state->cache_tree->oid);
 656
 657         return 0;
 658 }
 659
 660 struct tree* write_in_core_index_as_tree(struct repository *repo) {
 661         struct object_id o;
 662         int was_valid, ret;
 663
 664         struct index_state *index_state = repo->index;
 665         was_valid = index_state->cache_tree &&
 666                     cache_tree_fully_valid(index_state->cache_tree);
 667
 668         ret = write_index_as_tree_internal(&o, index_state, was_valid, 0, NULL);
 669         if (ret == WRITE_TREE_UNMERGED_INDEX) {
 670                 int i;
 671                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 672                 for (i = 0; i < index_state->cache_nr; i++) {
 673                         const struct cache_entry *ce = index_state->cache[i];
 674                         if (ce_stage(ce))
 675                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 676                                         (int)ce_namelen(ce), ce->name);
 677                 }
 678                 BUG("unmerged index entries when writing inmemory index");
 679         }
 680
 681         return lookup_tree(repo, &index_state->cache_tree->oid);
 682 }
 683
 684
 685 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 686 {
 687         int entries, was_valid;
 688         struct lock_file lock_file = LOCK_INIT;
 689         int ret;
 690
 691         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 692
 693         entries = read_index_from(index_state, index_path, get_git_dir());
 694         if (entries < 0) {
 695                 ret = WRITE_TREE_UNREADABLE_INDEX;
 696                 goto out;
 697         }
 698
 699         was_valid = !(flags & WRITE_TREE_IGNORE_CACHE_TREE) &&
 700                     index_state->cache_tree &&
 701                     cache_tree_fully_valid(index_state->cache_tree);
 702
 703         ret = write_index_as_tree_internal(oid, index_state, was_valid, flags,
 704                                            prefix);
 705         if (!ret && !was_valid) {
 706                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
 707                 /* Not being able to write is fine -- we are only interested
 708                  * in updating the cache-tree part, and if the next caller
 709                  * ends up using the old index with unupdated cache-tree part
 710                  * it misses the work we did here, but that is just a
 711                  * performance penalty and not a big deal.
 712                  */
 713         }
 714
 715 out:
 716         rollback_lock_file(&lock_file);
 717         return ret;
 718 }
 719
 720 static void prime_cache_tree_rec(struct repository *r,
 721                                  struct cache_tree *it,
 722                                  struct tree *tree)
 723 {
 724         struct tree_desc desc;
 725         struct name_entry entry;
 726         int cnt;
 727
 728         oidcpy(&it->oid, &tree->object.oid);
 729         init_tree_desc(&desc, tree->buffer, tree->size);
 730         cnt = 0;
 731         while (tree_entry(&desc, &entry)) {
 732                 if (!S_ISDIR(entry.mode))
 733                         cnt++;
 734                 else {
 735                         struct cache_tree_sub *sub;
 736                         struct tree *subtree = lookup_tree(r, &entry.oid);
 737                         if (!subtree->object.parsed)
 738                                 parse_tree(subtree);
 739                         sub = cache_tree_sub(it, entry.path);
 740                         sub->cache_tree = cache_tree();
 741                         prime_cache_tree_rec(r, sub->cache_tree, subtree);
 742                         cnt += sub->cache_tree->entry_count;
 743                 }
 744         }
 745         it->entry_count = cnt;
 746 }
 747
 748 void prime_cache_tree(struct repository *r,
 749                       struct index_state *istate,
 750                       struct tree *tree)
 751 {
 752         trace2_region_enter("cache-tree", "prime_cache_tree", the_repository);
 753         cache_tree_free(&istate->cache_tree);
 754         istate->cache_tree = cache_tree();
 755
 756         prime_cache_tree_rec(r, istate->cache_tree, tree);
 757         istate->cache_changed |= CACHE_TREE_CHANGED;
 758         trace2_region_leave("cache-tree", "prime_cache_tree", the_repository);
 759 }
 760
 761 /*
 762  * find the cache_tree that corresponds to the current level without
 763  * exploding the full path into textual form.  The root of the
 764  * cache tree is given as "root", and our current level is "info".
 765  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 766  * (2) Otherwise, find the cache_tree that corresponds to one level
 767  *     above us, and find ourselves in there.
 768  */
 769 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 770                                                          struct traverse_info *info)
 771 {
 772         struct cache_tree *our_parent;
 773
 774         if (!info->prev)
 775                 return root;
 776         our_parent = find_cache_tree_from_traversal(root, info->prev);
 777         return cache_tree_find(our_parent, info->name);
 778 }
 779
 780 int cache_tree_matches_traversal(struct cache_tree *root,
 781                                  struct name_entry *ent,
 782                                  struct traverse_info *info)
 783 {
 784         struct cache_tree *it;
 785
 786         it = find_cache_tree_from_traversal(root, info);
 787         it = cache_tree_find(it, ent->path);
 788         if (it && it->entry_count > 0 && oideq(&ent->oid, &it->oid))
 789                 return it->entry_count;
 790         return 0;
 791 }
 792
 793 static void verify_one(struct repository *r,
 794                        struct index_state *istate,
 795                        struct cache_tree *it,
 796                        struct strbuf *path)
 797 {
 798         int i, pos, len = path->len;
 799         struct strbuf tree_buf = STRBUF_INIT;
 800         struct object_id new_oid;
 801
 802         for (i = 0; i < it->subtree_nr; i++) {
 803                 strbuf_addf(path, "%s/", it->down[i]->name);
 804                 verify_one(r, istate, it->down[i]->cache_tree, path);
 805                 strbuf_setlen(path, len);
 806         }
 807
 808         if (it->entry_count < 0 ||
 809             /* no verification on tests (t7003) that replace trees */
 810             lookup_replace_object(r, &it->oid) != &it->oid)
 811                 return;
 812
 813         if (path->len) {
 814                 pos = index_name_pos(istate, path->buf, path->len);
 815                 pos = -pos - 1;
 816         } else {
 817                 pos = 0;
 818         }
 819
 820         i = 0;
 821         while (i < it->entry_count) {
 822                 struct cache_entry *ce = istate->cache[pos + i];
 823                 const char *slash;
 824                 struct cache_tree_sub *sub = NULL;
 825                 const struct object_id *oid;
 826                 const char *name;
 827                 unsigned mode;
 828                 int entlen;
 829
 830                 if (ce->ce_flags & (CE_STAGEMASK | CE_INTENT_TO_ADD | CE_REMOVE))
 831                         BUG("%s with flags 0x%x should not be in cache-tree",
 832                             ce->name, ce->ce_flags);
 833                 name = ce->name + path->len;
 834                 slash = strchr(name, '/');
 835                 if (slash) {
 836                         entlen = slash - name;
 837                         sub = find_subtree(it, ce->name + path->len, entlen, 0);
 838                         if (!sub || sub->cache_tree->entry_count < 0)
 839                                 BUG("bad subtree '%.*s'", entlen, name);
 840                         oid = &sub->cache_tree->oid;
 841                         mode = S_IFDIR;
 842                         i += sub->cache_tree->entry_count;
 843                 } else {
 844                         oid = &ce->oid;
 845                         mode = ce->ce_mode;
 846                         entlen = ce_namelen(ce) - path->len;
 847                         i++;
 848                 }
 849                 strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
 850                 strbuf_add(&tree_buf, oid->hash, r->hash_algo->rawsz);
 851         }
 852         hash_object_file(r->hash_algo, tree_buf.buf, tree_buf.len, tree_type,
 853                          &new_oid);
 854         if (!oideq(&new_oid, &it->oid))
 855                 BUG("cache-tree for path %.*s does not match. "
 856                     "Expected %s got %s", len, path->buf,
 857                     oid_to_hex(&new_oid), oid_to_hex(&it->oid));
 858         strbuf_setlen(path, len);
 859         strbuf_release(&tree_buf);
 860 }
 861
 862 void cache_tree_verify(struct repository *r, struct index_state *istate)
 863 {
 864         struct strbuf path = STRBUF_INIT;
 865
 866         if (!istate->cache_tree)
 867                 return;
 868         verify_one(r, istate, istate->cache_tree, &path);
 869         strbuf_release(&path);
 870 }