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 must_check_existence(const struct cache_entry *ce)
 241 {
 242         return !(has_promisor_remote() && ce_skip_worktree(ce));
 243 }
 244
 245 static int update_one(struct cache_tree *it,
 246                       struct cache_entry **cache,
 247                       int entries,
 248                       const char *base,
 249                       int baselen,
 250                       int *skip_count,
 251                       int flags)
 252 {
 253         struct strbuf buffer;
 254         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 255         int dryrun = flags & WRITE_TREE_DRY_RUN;
 256         int repair = flags & WRITE_TREE_REPAIR;
 257         int to_invalidate = 0;
 258         int i;
 259
 260         assert(!(dryrun && repair));
 261
 262         *skip_count = 0;
 263
 264         /*
 265          * If the first entry of this region is a sparse directory
 266          * entry corresponding exactly to 'base', then this cache_tree
 267          * struct is a "leaf" in the data structure, pointing to the
 268          * tree OID specified in the entry.
 269          */
 270         if (entries > 0) {
 271                 const struct cache_entry *ce = cache[0];
 272
 273                 if (S_ISSPARSEDIR(ce->ce_mode) &&
 274                     ce->ce_namelen == baselen &&
 275                     !strncmp(ce->name, base, baselen)) {
 276                         it->entry_count = 1;
 277                         oidcpy(&it->oid, &ce->oid);
 278                         return 1;
 279                 }
 280         }
 281
 282         if (0 <= it->entry_count && has_object_file(&it->oid))
 283                 return it->entry_count;
 284
 285         /*
 286          * We first scan for subtrees and update them; we start by
 287          * marking existing subtrees -- the ones that are unmarked
 288          * should not be in the result.
 289          */
 290         for (i = 0; i < it->subtree_nr; i++)
 291                 it->down[i]->used = 0;
 292
 293         /*
 294          * Find the subtrees and update them.
 295          */
 296         i = 0;
 297         while (i < entries) {
 298                 const struct cache_entry *ce = cache[i];
 299                 struct cache_tree_sub *sub;
 300                 const char *path, *slash;
 301                 int pathlen, sublen, subcnt, subskip;
 302
 303                 path = ce->name;
 304                 pathlen = ce_namelen(ce);
 305                 if (pathlen <= baselen || memcmp(base, path, baselen))
 306                         break; /* at the end of this level */
 307
 308                 slash = strchr(path + baselen, '/');
 309                 if (!slash) {
 310                         i++;
 311                         continue;
 312                 }
 313                 /*
 314                  * a/bbb/c (base = a/, slash = /c)
 315                  * ==>
 316                  * path+baselen = bbb/c, sublen = 3
 317                  */
 318                 sublen = slash - (path + baselen);
 319                 sub = find_subtree(it, path + baselen, sublen, 1);
 320                 if (!sub->cache_tree)
 321                         sub->cache_tree = cache_tree();
 322                 subcnt = update_one(sub->cache_tree,
 323                                     cache + i, entries - i,
 324                                     path,
 325                                     baselen + sublen + 1,
 326                                     &subskip,
 327                                     flags);
 328                 if (subcnt < 0)
 329                         return subcnt;
 330                 if (!subcnt)
 331                         die("index cache-tree records empty sub-tree");
 332                 i += subcnt;
 333                 sub->count = subcnt; /* to be used in the next loop */
 334                 *skip_count += subskip;
 335                 sub->used = 1;
 336         }
 337
 338         discard_unused_subtrees(it);
 339
 340         /*
 341          * Then write out the tree object for this level.
 342          */
 343         strbuf_init(&buffer, 8192);
 344
 345         i = 0;
 346         while (i < entries) {
 347                 const struct cache_entry *ce = cache[i];
 348                 struct cache_tree_sub *sub = NULL;
 349                 const char *path, *slash;
 350                 int pathlen, entlen;
 351                 const struct object_id *oid;
 352                 unsigned mode;
 353                 int expected_missing = 0;
 354                 int contains_ita = 0;
 355                 int ce_missing_ok;
 356
 357                 path = ce->name;
 358                 pathlen = ce_namelen(ce);
 359                 if (pathlen <= baselen || memcmp(base, path, baselen))
 360                         break; /* at the end of this level */
 361
 362                 slash = strchr(path + baselen, '/');
 363                 if (slash) {
 364                         entlen = slash - (path + baselen);
 365                         sub = find_subtree(it, path + baselen, entlen, 0);
 366                         if (!sub)
 367                                 die("cache-tree.c: '%.*s' in '%s' not found",
 368                                     entlen, path + baselen, path);
 369                         i += sub->count;
 370                         oid = &sub->cache_tree->oid;
 371                         mode = S_IFDIR;
 372                         contains_ita = sub->cache_tree->entry_count < 0;
 373                         if (contains_ita) {
 374                                 to_invalidate = 1;
 375                                 expected_missing = 1;
 376                         }
 377                 }
 378                 else {
 379                         oid = &ce->oid;
 380                         mode = ce->ce_mode;
 381                         entlen = pathlen - baselen;
 382                         i++;
 383                 }
 384
 385                 ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
 386                         !must_check_existence(ce);
 387                 if (is_null_oid(oid) ||
 388                     (!ce_missing_ok && !has_object_file(oid))) {
 389                         strbuf_release(&buffer);
 390                         if (expected_missing)
 391                                 return -1;
 392                         return error("invalid object %06o %s for '%.*s'",
 393                                 mode, oid_to_hex(oid), entlen+baselen, path);
 394                 }
 395
 396                 /*
 397                  * CE_REMOVE entries are removed before the index is
 398                  * written to disk. Skip them to remain consistent
 399                  * with the future on-disk index.
 400                  */
 401                 if (ce->ce_flags & CE_REMOVE) {
 402                         *skip_count = *skip_count + 1;
 403                         continue;
 404                 }
 405
 406                 /*
 407                  * CE_INTENT_TO_ADD entries exist on on-disk index but
 408                  * they are not part of generated trees. Invalidate up
 409                  * to root to force cache-tree users to read elsewhere.
 410                  */
 411                 if (!sub && ce_intent_to_add(ce)) {
 412                         to_invalidate = 1;
 413                         continue;
 414                 }
 415
 416                 /*
 417                  * "sub" can be an empty tree if all subentries are i-t-a.
 418                  */
 419                 if (contains_ita && is_empty_tree_oid(oid))
 420                         continue;
 421
 422                 strbuf_grow(&buffer, entlen + 100);
 423                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 424                 strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
 425
 426 #if DEBUG_CACHE_TREE
 427                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 428                         mode, entlen, path + baselen);
 429 #endif
 430         }
 431
 432         if (repair) {
 433                 struct object_id oid;
 434                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 435                                  tree_type, &oid);
 436                 if (has_object_file_with_flags(&oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 437                         oidcpy(&it->oid, &oid);
 438                 else
 439                         to_invalidate = 1;
 440         } else if (dryrun) {
 441                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 442                                  tree_type, &it->oid);
 443         } else if (write_object_file_flags(buffer.buf, buffer.len, tree_type,
 444                                            &it->oid, flags & WRITE_TREE_SILENT
 445                                            ? HASH_SILENT : 0)) {
 446                 strbuf_release(&buffer);
 447                 return -1;
 448         }
 449
 450         strbuf_release(&buffer);
 451         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 452 #if DEBUG_CACHE_TREE
 453         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 454                 it->entry_count, it->subtree_nr,
 455                 oid_to_hex(&it->oid));
 456 #endif
 457         return i;
 458 }
 459
 460 int cache_tree_update(struct index_state *istate, int flags)
 461 {
 462         int skip, i;
 463
 464         i = verify_cache(istate, flags);
 465
 466         if (i)
 467                 return i;
 468
 469         if (!istate->cache_tree)
 470                 istate->cache_tree = cache_tree();
 471
 472         if (!(flags & WRITE_TREE_MISSING_OK) && has_promisor_remote())
 473                 prefetch_cache_entries(istate, must_check_existence);
 474
 475         trace_performance_enter();
 476         trace2_region_enter("cache_tree", "update", the_repository);
 477         i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
 478                        "", 0, &skip, flags);
 479         trace2_region_leave("cache_tree", "update", the_repository);
 480         trace_performance_leave("cache_tree_update");
 481         if (i < 0)
 482                 return i;
 483         istate->cache_changed |= CACHE_TREE_CHANGED;
 484         return 0;
 485 }
 486
 487 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 488                       const char *path, int pathlen)
 489 {
 490         int i;
 491
 492         /* One "cache-tree" entry consists of the following:
 493          * path (NUL terminated)
 494          * entry_count, subtree_nr ("%d %d\n")
 495          * tree-sha1 (missing if invalid)
 496          * subtree_nr "cache-tree" entries for subtrees.
 497          */
 498         strbuf_grow(buffer, pathlen + 100);
 499         strbuf_add(buffer, path, pathlen);
 500         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 501
 502 #if DEBUG_CACHE_TREE
 503         if (0 <= it->entry_count)
 504                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 505                         pathlen, path, it->entry_count, it->subtree_nr,
 506                         oid_to_hex(&it->oid));
 507         else
 508                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 509                         pathlen, path, it->subtree_nr);
 510 #endif
 511
 512         if (0 <= it->entry_count) {
 513                 strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
 514         }
 515         for (i = 0; i < it->subtree_nr; i++) {
 516                 struct cache_tree_sub *down = it->down[i];
 517                 if (i) {
 518                         struct cache_tree_sub *prev = it->down[i-1];
 519                         if (subtree_name_cmp(down->name, down->namelen,
 520                                              prev->name, prev->namelen) <= 0)
 521                                 die("fatal - unsorted cache subtree");
 522                 }
 523                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 524         }
 525 }
 526
 527 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 528 {
 529         trace2_region_enter("cache_tree", "write", the_repository);
 530         write_one(sb, root, "", 0);
 531         trace2_region_leave("cache_tree", "write", the_repository);
 532 }
 533
 534 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 535 {
 536         const char *buf = *buffer;
 537         unsigned long size = *size_p;
 538         const char *cp;
 539         char *ep;
 540         struct cache_tree *it;
 541         int i, subtree_nr;
 542         const unsigned rawsz = the_hash_algo->rawsz;
 543
 544         it = NULL;
 545         /* skip name, but make sure name exists */
 546         while (size && *buf) {
 547                 size--;
 548                 buf++;
 549         }
 550         if (!size)
 551                 goto free_return;
 552         buf++; size--;
 553         it = cache_tree();
 554
 555         cp = buf;
 556         it->entry_count = strtol(cp, &ep, 10);
 557         if (cp == ep)
 558                 goto free_return;
 559         cp = ep;
 560         subtree_nr = strtol(cp, &ep, 10);
 561         if (cp == ep)
 562                 goto free_return;
 563         while (size && *buf && *buf != '\n') {
 564                 size--;
 565                 buf++;
 566         }
 567         if (!size)
 568                 goto free_return;
 569         buf++; size--;
 570         if (0 <= it->entry_count) {
 571                 if (size < rawsz)
 572                         goto free_return;
 573                 oidread(&it->oid, (const unsigned char *)buf);
 574                 buf += rawsz;
 575                 size -= rawsz;
 576         }
 577
 578 #if DEBUG_CACHE_TREE
 579         if (0 <= it->entry_count)
 580                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 581                         *buffer, it->entry_count, subtree_nr,
 582                         oid_to_hex(&it->oid));
 583         else
 584                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 585                         *buffer, subtree_nr);
 586 #endif
 587
 588         /*
 589          * Just a heuristic -- we do not add directories that often but
 590          * we do not want to have to extend it immediately when we do,
 591          * hence +2.
 592          */
 593         it->subtree_alloc = subtree_nr + 2;
 594         CALLOC_ARRAY(it->down, it->subtree_alloc);
 595         for (i = 0; i < subtree_nr; i++) {
 596                 /* read each subtree */
 597                 struct cache_tree *sub;
 598                 struct cache_tree_sub *subtree;
 599                 const char *name = buf;
 600
 601                 sub = read_one(&buf, &size);
 602                 if (!sub)
 603                         goto free_return;
 604                 subtree = cache_tree_sub(it, name);
 605                 subtree->cache_tree = sub;
 606         }
 607         if (subtree_nr != it->subtree_nr)
 608                 die("cache-tree: internal error");
 609         *buffer = buf;
 610         *size_p = size;
 611         return it;
 612
 613  free_return:
 614         cache_tree_free(&it);
 615         return NULL;
 616 }
 617
 618 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 619 {
 620         struct cache_tree *result;
 621
 622         if (buffer[0])
 623                 return NULL; /* not the whole tree */
 624
 625         trace2_region_enter("cache_tree", "read", the_repository);
 626         result = read_one(&buffer, &size);
 627         trace2_region_leave("cache_tree", "read", the_repository);
 628
 629         return result;
 630 }
 631
 632 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 633 {
 634         if (!it)
 635                 return NULL;
 636         while (*path) {
 637                 const char *slash;
 638                 struct cache_tree_sub *sub;
 639
 640                 slash = strchrnul(path, '/');
 641                 /*
 642                  * Between path and slash is the name of the subtree
 643                  * to look for.
 644                  */
 645                 sub = find_subtree(it, path, slash - path, 0);
 646                 if (!sub)
 647                         return NULL;
 648                 it = sub->cache_tree;
 649
 650                 path = slash;
 651                 while (*path == '/')
 652                         path++;
 653         }
 654         return it;
 655 }
 656
 657 static int write_index_as_tree_internal(struct object_id *oid,
 658                                         struct index_state *index_state,
 659                                         int cache_tree_valid,
 660                                         int flags,
 661                                         const char *prefix)
 662 {
 663         if (flags & WRITE_TREE_IGNORE_CACHE_TREE) {
 664                 cache_tree_free(&index_state->cache_tree);
 665                 cache_tree_valid = 0;
 666         }
 667
 668         if (!cache_tree_valid && cache_tree_update(index_state, flags) < 0)
 669                 return WRITE_TREE_UNMERGED_INDEX;
 670
 671         if (prefix) {
 672                 struct cache_tree *subtree;
 673                 subtree = cache_tree_find(index_state->cache_tree, prefix);
 674                 if (!subtree)
 675                         return WRITE_TREE_PREFIX_ERROR;
 676                 oidcpy(oid, &subtree->oid);
 677         }
 678         else
 679                 oidcpy(oid, &index_state->cache_tree->oid);
 680
 681         return 0;
 682 }
 683
 684 struct tree* write_in_core_index_as_tree(struct repository *repo) {
 685         struct object_id o;
 686         int was_valid, ret;
 687
 688         struct index_state *index_state = repo->index;
 689         was_valid = index_state->cache_tree &&
 690                     cache_tree_fully_valid(index_state->cache_tree);
 691
 692         ret = write_index_as_tree_internal(&o, index_state, was_valid, 0, NULL);
 693         if (ret == WRITE_TREE_UNMERGED_INDEX) {
 694                 int i;
 695                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 696                 for (i = 0; i < index_state->cache_nr; i++) {
 697                         const struct cache_entry *ce = index_state->cache[i];
 698                         if (ce_stage(ce))
 699                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 700                                         (int)ce_namelen(ce), ce->name);
 701                 }
 702                 BUG("unmerged index entries when writing inmemory index");
 703         }
 704
 705         return lookup_tree(repo, &index_state->cache_tree->oid);
 706 }
 707
 708
 709 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 710 {
 711         int entries, was_valid;
 712         struct lock_file lock_file = LOCK_INIT;
 713         int ret;
 714
 715         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 716
 717         entries = read_index_from(index_state, index_path, get_git_dir());
 718         if (entries < 0) {
 719                 ret = WRITE_TREE_UNREADABLE_INDEX;
 720                 goto out;
 721         }
 722
 723         was_valid = !(flags & WRITE_TREE_IGNORE_CACHE_TREE) &&
 724                     index_state->cache_tree &&
 725                     cache_tree_fully_valid(index_state->cache_tree);
 726
 727         ret = write_index_as_tree_internal(oid, index_state, was_valid, flags,
 728                                            prefix);
 729         if (!ret && !was_valid) {
 730                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
 731                 /* Not being able to write is fine -- we are only interested
 732                  * in updating the cache-tree part, and if the next caller
 733                  * ends up using the old index with unupdated cache-tree part
 734                  * it misses the work we did here, but that is just a
 735                  * performance penalty and not a big deal.
 736                  */
 737         }
 738
 739 out:
 740         rollback_lock_file(&lock_file);
 741         return ret;
 742 }
 743
 744 static void prime_cache_tree_sparse_dir(struct cache_tree *it,
 745                                         struct tree *tree)
 746 {
 747
 748         oidcpy(&it->oid, &tree->object.oid);
 749         it->entry_count = 1;
 750 }
 751
 752 static void prime_cache_tree_rec(struct repository *r,
 753                                  struct cache_tree *it,
 754                                  struct tree *tree,
 755                                  struct strbuf *tree_path)
 756 {
 757         struct tree_desc desc;
 758         struct name_entry entry;
 759         int cnt;
 760         int base_path_len = tree_path->len;
 761
 762         oidcpy(&it->oid, &tree->object.oid);
 763
 764         init_tree_desc(&desc, tree->buffer, tree->size);
 765         cnt = 0;
 766         while (tree_entry(&desc, &entry)) {
 767                 if (!S_ISDIR(entry.mode))
 768                         cnt++;
 769                 else {
 770                         struct cache_tree_sub *sub;
 771                         struct tree *subtree = lookup_tree(r, &entry.oid);
 772
 773                         if (!subtree->object.parsed)
 774                                 parse_tree(subtree);
 775                         sub = cache_tree_sub(it, entry.path);
 776                         sub->cache_tree = cache_tree();
 777
 778                         /*
 779                          * Recursively-constructed subtree path is only needed when working
 780                          * in a sparse index (where it's used to determine whether the
 781                          * subtree is a sparse directory in the index).
 782                          */
 783                         if (r->index->sparse_index) {
 784                                 strbuf_setlen(tree_path, base_path_len);
 785                                 strbuf_grow(tree_path, base_path_len + entry.pathlen + 1);
 786                                 strbuf_add(tree_path, entry.path, entry.pathlen);
 787                                 strbuf_addch(tree_path, '/');
 788                         }
 789
 790                         /*
 791                          * If a sparse index is in use, the directory being processed may be
 792                          * sparse. To confirm that, we can check whether an entry with that
 793                          * exact name exists in the index. If it does, the created subtree
 794                          * should be sparse. Otherwise, cache tree expansion should continue
 795                          * as normal.
 796                          */
 797                         if (r->index->sparse_index &&
 798                             index_entry_exists(r->index, tree_path->buf, tree_path->len))
 799                                 prime_cache_tree_sparse_dir(sub->cache_tree, subtree);
 800                         else
 801                                 prime_cache_tree_rec(r, sub->cache_tree, subtree, tree_path);
 802                         cnt += sub->cache_tree->entry_count;
 803                 }
 804         }
 805
 806         it->entry_count = cnt;
 807 }
 808
 809 void prime_cache_tree(struct repository *r,
 810                       struct index_state *istate,
 811                       struct tree *tree)
 812 {
 813         struct strbuf tree_path = STRBUF_INIT;
 814
 815         trace2_region_enter("cache-tree", "prime_cache_tree", the_repository);
 816         cache_tree_free(&istate->cache_tree);
 817         istate->cache_tree = cache_tree();
 818
 819         prime_cache_tree_rec(r, istate->cache_tree, tree, &tree_path);
 820         strbuf_release(&tree_path);
 821         istate->cache_changed |= CACHE_TREE_CHANGED;
 822         trace2_region_leave("cache-tree", "prime_cache_tree", the_repository);
 823 }
 824
 825 /*
 826  * find the cache_tree that corresponds to the current level without
 827  * exploding the full path into textual form.  The root of the
 828  * cache tree is given as "root", and our current level is "info".
 829  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 830  * (2) Otherwise, find the cache_tree that corresponds to one level
 831  *     above us, and find ourselves in there.
 832  */
 833 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 834                                                          struct traverse_info *info)
 835 {
 836         struct cache_tree *our_parent;
 837
 838         if (!info->prev)
 839                 return root;
 840         our_parent = find_cache_tree_from_traversal(root, info->prev);
 841         return cache_tree_find(our_parent, info->name);
 842 }
 843
 844 int cache_tree_matches_traversal(struct cache_tree *root,
 845                                  struct name_entry *ent,
 846                                  struct traverse_info *info)
 847 {
 848         struct cache_tree *it;
 849
 850         it = find_cache_tree_from_traversal(root, info);
 851         it = cache_tree_find(it, ent->path);
 852         if (it && it->entry_count > 0 && oideq(&ent->oid, &it->oid))
 853                 return it->entry_count;
 854         return 0;
 855 }
 856
 857 static void verify_one_sparse(struct repository *r,
 858                               struct index_state *istate,
 859                               struct cache_tree *it,
 860                               struct strbuf *path,
 861                               int pos)
 862 {
 863         struct cache_entry *ce = istate->cache[pos];
 864
 865         if (!S_ISSPARSEDIR(ce->ce_mode))
 866                 BUG("directory '%s' is present in index, but not sparse",
 867                     path->buf);
 868 }
 869
 870 /*
 871  * Returns:
 872  *  0 - Verification completed.
 873  *  1 - Restart verification - a call to ensure_full_index() freed the cache
 874  *      tree that is being verified and verification needs to be restarted from
 875  *      the new toplevel cache tree.
 876  */
 877 static int verify_one(struct repository *r,
 878                       struct index_state *istate,
 879                       struct cache_tree *it,
 880                       struct strbuf *path)
 881 {
 882         int i, pos, len = path->len;
 883         struct strbuf tree_buf = STRBUF_INIT;
 884         struct object_id new_oid;
 885
 886         for (i = 0; i < it->subtree_nr; i++) {
 887                 strbuf_addf(path, "%s/", it->down[i]->name);
 888                 if (verify_one(r, istate, it->down[i]->cache_tree, path))
 889                         return 1;
 890                 strbuf_setlen(path, len);
 891         }
 892
 893         if (it->entry_count < 0 ||
 894             /* no verification on tests (t7003) that replace trees */
 895             lookup_replace_object(r, &it->oid) != &it->oid)
 896                 return 0;
 897
 898         if (path->len) {
 899                 /*
 900                  * If the index is sparse and the cache tree is not
 901                  * index_name_pos() may trigger ensure_full_index() which will
 902                  * free the tree that is being verified.
 903                  */
 904                 int is_sparse = istate->sparse_index;
 905                 pos = index_name_pos(istate, path->buf, path->len);
 906                 if (is_sparse && !istate->sparse_index)
 907                         return 1;
 908
 909                 if (pos >= 0) {
 910                         verify_one_sparse(r, istate, it, path, pos);
 911                         return 0;
 912                 }
 913
 914                 pos = -pos - 1;
 915         } else {
 916                 pos = 0;
 917         }
 918
 919         i = 0;
 920         while (i < it->entry_count) {
 921                 struct cache_entry *ce = istate->cache[pos + i];
 922                 const char *slash;
 923                 struct cache_tree_sub *sub = NULL;
 924                 const struct object_id *oid;
 925                 const char *name;
 926                 unsigned mode;
 927                 int entlen;
 928
 929                 if (ce->ce_flags & (CE_STAGEMASK | CE_INTENT_TO_ADD | CE_REMOVE))
 930                         BUG("%s with flags 0x%x should not be in cache-tree",
 931                             ce->name, ce->ce_flags);
 932                 name = ce->name + path->len;
 933                 slash = strchr(name, '/');
 934                 if (slash) {
 935                         entlen = slash - name;
 936                         sub = find_subtree(it, ce->name + path->len, entlen, 0);
 937                         if (!sub || sub->cache_tree->entry_count < 0)
 938                                 BUG("bad subtree '%.*s'", entlen, name);
 939                         oid = &sub->cache_tree->oid;
 940                         mode = S_IFDIR;
 941                         i += sub->cache_tree->entry_count;
 942                 } else {
 943                         oid = &ce->oid;
 944                         mode = ce->ce_mode;
 945                         entlen = ce_namelen(ce) - path->len;
 946                         i++;
 947                 }
 948                 strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
 949                 strbuf_add(&tree_buf, oid->hash, r->hash_algo->rawsz);
 950         }
 951         hash_object_file(r->hash_algo, tree_buf.buf, tree_buf.len, tree_type,
 952                          &new_oid);
 953         if (!oideq(&new_oid, &it->oid))
 954                 BUG("cache-tree for path %.*s does not match. "
 955                     "Expected %s got %s", len, path->buf,
 956                     oid_to_hex(&new_oid), oid_to_hex(&it->oid));
 957         strbuf_setlen(path, len);
 958         strbuf_release(&tree_buf);
 959         return 0;
 960 }
 961
 962 void cache_tree_verify(struct repository *r, struct index_state *istate)
 963 {
 964         struct strbuf path = STRBUF_INIT;
 965
 966         if (!istate->cache_tree)
 967                 return;
 968         if (verify_one(r, istate, istate->cache_tree, &path)) {
 969                 strbuf_reset(&path);
 970                 if (verify_one(r, istate, istate->cache_tree, &path))
 971                         BUG("ensure_full_index() called twice while verifying cache tree");
 972         }
 973         strbuf_release(&path);
 974 }