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 "bulk-checkin.h"
   7 #include "object-store.h"
   8 #include "replace-object.h"
   9 #include "promisor-remote.h"
  10 #include "sparse-index.h"
  11
  12 #ifndef DEBUG_CACHE_TREE
  13 #define DEBUG_CACHE_TREE 0
  14 #endif
  15
  16 struct cache_tree *cache_tree(void)
  17 {
  18         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  19         it->entry_count = -1;
  20         return it;
  21 }
  22
  23 void cache_tree_free(struct cache_tree **it_p)
  24 {
  25         int i;
  26         struct cache_tree *it = *it_p;
  27
  28         if (!it)
  29                 return;
  30         for (i = 0; i < it->subtree_nr; i++)
  31                 if (it->down[i]) {
  32                         cache_tree_free(&it->down[i]->cache_tree);
  33                         free(it->down[i]);
  34                 }
  35         free(it->down);
  36         free(it);
  37         *it_p = NULL;
  38 }
  39
  40 static int subtree_name_cmp(const char *one, int onelen,
  41                             const char *two, int twolen)
  42 {
  43         if (onelen < twolen)
  44                 return -1;
  45         if (twolen < onelen)
  46                 return 1;
  47         return memcmp(one, two, onelen);
  48 }
  49
  50 int cache_tree_subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  51 {
  52         struct cache_tree_sub **down = it->down;
  53         int lo, hi;
  54         lo = 0;
  55         hi = it->subtree_nr;
  56         while (lo < hi) {
  57                 int mi = lo + (hi - lo) / 2;
  58                 struct cache_tree_sub *mdl = down[mi];
  59                 int cmp = subtree_name_cmp(path, pathlen,
  60                                            mdl->name, mdl->namelen);
  61                 if (!cmp)
  62                         return mi;
  63                 if (cmp < 0)
  64                         hi = mi;
  65                 else
  66                         lo = mi + 1;
  67         }
  68         return -lo-1;
  69 }
  70
  71 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  72                                            const char *path,
  73                                            int pathlen,
  74                                            int create)
  75 {
  76         struct cache_tree_sub *down;
  77         int pos = cache_tree_subtree_pos(it, path, pathlen);
  78         if (0 <= pos)
  79                 return it->down[pos];
  80         if (!create)
  81                 return NULL;
  82
  83         pos = -pos-1;
  84         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
  85         it->subtree_nr++;
  86
  87         FLEX_ALLOC_MEM(down, name, path, pathlen);
  88         down->cache_tree = NULL;
  89         down->namelen = pathlen;
  90
  91         if (pos < it->subtree_nr)
  92                 MOVE_ARRAY(it->down + pos + 1, it->down + pos,
  93                            it->subtree_nr - pos - 1);
  94         it->down[pos] = down;
  95         return down;
  96 }
  97
  98 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
  99 {
 100         int pathlen = strlen(path);
 101         return find_subtree(it, path, pathlen, 1);
 102 }
 103
 104 static int do_invalidate_path(struct cache_tree *it, const char *path)
 105 {
 106         /* a/b/c
 107          * ==> invalidate self
 108          * ==> find "a", have it invalidate "b/c"
 109          * a
 110          * ==> invalidate self
 111          * ==> if "a" exists as a subtree, remove it.
 112          */
 113         const char *slash;
 114         int namelen;
 115         struct cache_tree_sub *down;
 116
 117 #if DEBUG_CACHE_TREE
 118         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 119 #endif
 120
 121         if (!it)
 122                 return 0;
 123         slash = strchrnul(path, '/');
 124         namelen = slash - path;
 125         it->entry_count = -1;
 126         if (!*slash) {
 127                 int pos;
 128                 pos = cache_tree_subtree_pos(it, path, namelen);
 129                 if (0 <= pos) {
 130                         cache_tree_free(&it->down[pos]->cache_tree);
 131                         free(it->down[pos]);
 132                         /* 0 1 2 3 4 5
 133                          *       ^     ^subtree_nr = 6
 134                          *       pos
 135                          * move 4 and 5 up one place (2 entries)
 136                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 137                          */
 138                         MOVE_ARRAY(it->down + pos, it->down + pos + 1,
 139                                    it->subtree_nr - pos - 1);
 140                         it->subtree_nr--;
 141                 }
 142                 return 1;
 143         }
 144         down = find_subtree(it, path, namelen, 0);
 145         if (down)
 146                 do_invalidate_path(down->cache_tree, slash + 1);
 147         return 1;
 148 }
 149
 150 void cache_tree_invalidate_path(struct index_state *istate, const char *path)
 151 {
 152         if (do_invalidate_path(istate->cache_tree, path))
 153                 istate->cache_changed |= CACHE_TREE_CHANGED;
 154 }
 155
 156 static int verify_cache(struct index_state *istate, int flags)
 157 {
 158         unsigned i, funny;
 159         int silent = flags & WRITE_TREE_SILENT;
 160
 161         /* Verify that the tree is merged */
 162         funny = 0;
 163         for (i = 0; i < istate->cache_nr; i++) {
 164                 const struct cache_entry *ce = istate->cache[i];
 165                 if (ce_stage(ce)) {
 166                         if (silent)
 167                                 return -1;
 168                         if (10 < ++funny) {
 169                                 fprintf(stderr, "...\n");
 170                                 break;
 171                         }
 172                         fprintf(stderr, "%s: unmerged (%s)\n",
 173                                 ce->name, oid_to_hex(&ce->oid));
 174                 }
 175         }
 176         if (funny)
 177                 return -1;
 178
 179         /* Also verify that the cache does not have path and path/file
 180          * at the same time.  At this point we know the cache has only
 181          * stage 0 entries.
 182          */
 183         funny = 0;
 184         for (i = 0; i + 1 < istate->cache_nr; i++) {
 185                 /* path/file always comes after path because of the way
 186                  * the cache is sorted.  Also path can appear only once,
 187                  * which means conflicting one would immediately follow.
 188                  */
 189                 const struct cache_entry *this_ce = istate->cache[i];
 190                 const struct cache_entry *next_ce = istate->cache[i + 1];
 191                 const char *this_name = this_ce->name;
 192                 const char *next_name = next_ce->name;
 193                 int this_len = ce_namelen(this_ce);
 194                 if (this_len < ce_namelen(next_ce) &&
 195                     next_name[this_len] == '/' &&
 196                     strncmp(this_name, next_name, this_len) == 0) {
 197                         if (10 < ++funny) {
 198                                 fprintf(stderr, "...\n");
 199                                 break;
 200                         }
 201                         fprintf(stderr, "You have both %s and %s\n",
 202                                 this_name, next_name);
 203                 }
 204         }
 205         if (funny)
 206                 return -1;
 207         return 0;
 208 }
 209
 210 static void discard_unused_subtrees(struct cache_tree *it)
 211 {
 212         struct cache_tree_sub **down = it->down;
 213         int nr = it->subtree_nr;
 214         int dst, src;
 215         for (dst = src = 0; src < nr; src++) {
 216                 struct cache_tree_sub *s = down[src];
 217                 if (s->used)
 218                         down[dst++] = s;
 219                 else {
 220                         cache_tree_free(&s->cache_tree);
 221                         free(s);
 222                         it->subtree_nr--;
 223                 }
 224         }
 225 }
 226
 227 int cache_tree_fully_valid(struct cache_tree *it)
 228 {
 229         int i;
 230         if (!it)
 231                 return 0;
 232         if (it->entry_count < 0 || !has_object_file(&it->oid))
 233                 return 0;
 234         for (i = 0; i < it->subtree_nr; i++) {
 235                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 236                         return 0;
 237         }
 238         return 1;
 239 }
 240
 241 static int must_check_existence(const struct cache_entry *ce)
 242 {
 243         return !(has_promisor_remote() && ce_skip_worktree(ce));
 244 }
 245
 246 static int update_one(struct cache_tree *it,
 247                       struct cache_entry **cache,
 248                       int entries,
 249                       const char *base,
 250                       int baselen,
 251                       int *skip_count,
 252                       int flags)
 253 {
 254         struct strbuf buffer;
 255         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 256         int dryrun = flags & WRITE_TREE_DRY_RUN;
 257         int repair = flags & WRITE_TREE_REPAIR;
 258         int to_invalidate = 0;
 259         int i;
 260
 261         assert(!(dryrun && repair));
 262
 263         *skip_count = 0;
 264
 265         /*
 266          * If the first entry of this region is a sparse directory
 267          * entry corresponding exactly to 'base', then this cache_tree
 268          * struct is a "leaf" in the data structure, pointing to the
 269          * tree OID specified in the entry.
 270          */
 271         if (entries > 0) {
 272                 const struct cache_entry *ce = cache[0];
 273
 274                 if (S_ISSPARSEDIR(ce->ce_mode) &&
 275                     ce->ce_namelen == baselen &&
 276                     !strncmp(ce->name, base, baselen)) {
 277                         it->entry_count = 1;
 278                         oidcpy(&it->oid, &ce->oid);
 279                         return 1;
 280                 }
 281         }
 282
 283         if (0 <= it->entry_count && has_object_file(&it->oid))
 284                 return it->entry_count;
 285
 286         /*
 287          * We first scan for subtrees and update them; we start by
 288          * marking existing subtrees -- the ones that are unmarked
 289          * should not be in the result.
 290          */
 291         for (i = 0; i < it->subtree_nr; i++)
 292                 it->down[i]->used = 0;
 293
 294         /*
 295          * Find the subtrees and update them.
 296          */
 297         i = 0;
 298         while (i < entries) {
 299                 const struct cache_entry *ce = cache[i];
 300                 struct cache_tree_sub *sub;
 301                 const char *path, *slash;
 302                 int pathlen, sublen, subcnt, subskip;
 303
 304                 path = ce->name;
 305                 pathlen = ce_namelen(ce);
 306                 if (pathlen <= baselen || memcmp(base, path, baselen))
 307                         break; /* at the end of this level */
 308
 309                 slash = strchr(path + baselen, '/');
 310                 if (!slash) {
 311                         i++;
 312                         continue;
 313                 }
 314                 /*
 315                  * a/bbb/c (base = a/, slash = /c)
 316                  * ==>
 317                  * path+baselen = bbb/c, sublen = 3
 318                  */
 319                 sublen = slash - (path + baselen);
 320                 sub = find_subtree(it, path + baselen, sublen, 1);
 321                 if (!sub->cache_tree)
 322                         sub->cache_tree = cache_tree();
 323                 subcnt = update_one(sub->cache_tree,
 324                                     cache + i, entries - i,
 325                                     path,
 326                                     baselen + sublen + 1,
 327                                     &subskip,
 328                                     flags);
 329                 if (subcnt < 0)
 330                         return subcnt;
 331                 if (!subcnt)
 332                         die("index cache-tree records empty sub-tree");
 333                 i += subcnt;
 334                 sub->count = subcnt; /* to be used in the next loop */
 335                 *skip_count += subskip;
 336                 sub->used = 1;
 337         }
 338
 339         discard_unused_subtrees(it);
 340
 341         /*
 342          * Then write out the tree object for this level.
 343          */
 344         strbuf_init(&buffer, 8192);
 345
 346         i = 0;
 347         while (i < entries) {
 348                 const struct cache_entry *ce = cache[i];
 349                 struct cache_tree_sub *sub = NULL;
 350                 const char *path, *slash;
 351                 int pathlen, entlen;
 352                 const struct object_id *oid;
 353                 unsigned mode;
 354                 int expected_missing = 0;
 355                 int contains_ita = 0;
 356                 int ce_missing_ok;
 357
 358                 path = ce->name;
 359                 pathlen = ce_namelen(ce);
 360                 if (pathlen <= baselen || memcmp(base, path, baselen))
 361                         break; /* at the end of this level */
 362
 363                 slash = strchr(path + baselen, '/');
 364                 if (slash) {
 365                         entlen = slash - (path + baselen);
 366                         sub = find_subtree(it, path + baselen, entlen, 0);
 367                         if (!sub)
 368                                 die("cache-tree.c: '%.*s' in '%s' not found",
 369                                     entlen, path + baselen, path);
 370                         i += sub->count;
 371                         oid = &sub->cache_tree->oid;
 372                         mode = S_IFDIR;
 373                         contains_ita = sub->cache_tree->entry_count < 0;
 374                         if (contains_ita) {
 375                                 to_invalidate = 1;
 376                                 expected_missing = 1;
 377                         }
 378                 }
 379                 else {
 380                         oid = &ce->oid;
 381                         mode = ce->ce_mode;
 382                         entlen = pathlen - baselen;
 383                         i++;
 384                 }
 385
 386                 ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
 387                         !must_check_existence(ce);
 388                 if (is_null_oid(oid) ||
 389                     (!ce_missing_ok && !has_object_file(oid))) {
 390                         strbuf_release(&buffer);
 391                         if (expected_missing)
 392                                 return -1;
 393                         return error("invalid object %06o %s for '%.*s'",
 394                                 mode, oid_to_hex(oid), entlen+baselen, path);
 395                 }
 396
 397                 /*
 398                  * CE_REMOVE entries are removed before the index is
 399                  * written to disk. Skip them to remain consistent
 400                  * with the future on-disk index.
 401                  */
 402                 if (ce->ce_flags & CE_REMOVE) {
 403                         *skip_count = *skip_count + 1;
 404                         continue;
 405                 }
 406
 407                 /*
 408                  * CE_INTENT_TO_ADD entries exist in on-disk index but
 409                  * they are not part of generated trees. Invalidate up
 410                  * to root to force cache-tree users to read elsewhere.
 411                  */
 412                 if (!sub && ce_intent_to_add(ce)) {
 413                         to_invalidate = 1;
 414                         continue;
 415                 }
 416
 417                 /*
 418                  * "sub" can be an empty tree if all subentries are i-t-a.
 419                  */
 420                 if (contains_ita && is_empty_tree_oid(oid))
 421                         continue;
 422
 423                 strbuf_grow(&buffer, entlen + 100);
 424                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 425                 strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
 426
 427 #if DEBUG_CACHE_TREE
 428                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 429                         mode, entlen, path + baselen);
 430 #endif
 431         }
 432
 433         if (repair) {
 434                 struct object_id oid;
 435                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 436                                  OBJ_TREE, &oid);
 437                 if (has_object_file_with_flags(&oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 438                         oidcpy(&it->oid, &oid);
 439                 else
 440                         to_invalidate = 1;
 441         } else if (dryrun) {
 442                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 443                                  OBJ_TREE, &it->oid);
 444         } else if (write_object_file_flags(buffer.buf, buffer.len, OBJ_TREE,
 445                                            &it->oid, flags & WRITE_TREE_SILENT
 446                                            ? HASH_SILENT : 0)) {
 447                 strbuf_release(&buffer);
 448                 return -1;
 449         }
 450
 451         strbuf_release(&buffer);
 452         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 453 #if DEBUG_CACHE_TREE
 454         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 455                 it->entry_count, it->subtree_nr,
 456                 oid_to_hex(&it->oid));
 457 #endif
 458         return i;
 459 }
 460
 461 int cache_tree_update(struct index_state *istate, int flags)
 462 {
 463         int skip, i;
 464
 465         i = verify_cache(istate, flags);
 466
 467         if (i)
 468                 return i;
 469
 470         if (!istate->cache_tree)
 471                 istate->cache_tree = cache_tree();
 472
 473         if (!(flags & WRITE_TREE_MISSING_OK) && has_promisor_remote())
 474                 prefetch_cache_entries(istate, must_check_existence);
 475
 476         trace_performance_enter();
 477         trace2_region_enter("cache_tree", "update", the_repository);
 478         begin_odb_transaction();
 479         i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
 480                        "", 0, &skip, flags);
 481         end_odb_transaction();
 482         trace2_region_leave("cache_tree", "update", the_repository);
 483         trace_performance_leave("cache_tree_update");
 484         if (i < 0)
 485                 return i;
 486         istate->cache_changed |= CACHE_TREE_CHANGED;
 487         return 0;
 488 }
 489
 490 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 491                       const char *path, int pathlen)
 492 {
 493         int i;
 494
 495         /* One "cache-tree" entry consists of the following:
 496          * path (NUL terminated)
 497          * entry_count, subtree_nr ("%d %d\n")
 498          * tree-sha1 (missing if invalid)
 499          * subtree_nr "cache-tree" entries for subtrees.
 500          */
 501         strbuf_grow(buffer, pathlen + 100);
 502         strbuf_add(buffer, path, pathlen);
 503         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 504
 505 #if DEBUG_CACHE_TREE
 506         if (0 <= it->entry_count)
 507                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 508                         pathlen, path, it->entry_count, it->subtree_nr,
 509                         oid_to_hex(&it->oid));
 510         else
 511                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 512                         pathlen, path, it->subtree_nr);
 513 #endif
 514
 515         if (0 <= it->entry_count) {
 516                 strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
 517         }
 518         for (i = 0; i < it->subtree_nr; i++) {
 519                 struct cache_tree_sub *down = it->down[i];
 520                 if (i) {
 521                         struct cache_tree_sub *prev = it->down[i-1];
 522                         if (subtree_name_cmp(down->name, down->namelen,
 523                                              prev->name, prev->namelen) <= 0)
 524                                 die("fatal - unsorted cache subtree");
 525                 }
 526                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 527         }
 528 }
 529
 530 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 531 {
 532         trace2_region_enter("cache_tree", "write", the_repository);
 533         write_one(sb, root, "", 0);
 534         trace2_region_leave("cache_tree", "write", the_repository);
 535 }
 536
 537 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 538 {
 539         const char *buf = *buffer;
 540         unsigned long size = *size_p;
 541         const char *cp;
 542         char *ep;
 543         struct cache_tree *it;
 544         int i, subtree_nr;
 545         const unsigned rawsz = the_hash_algo->rawsz;
 546
 547         it = NULL;
 548         /* skip name, but make sure name exists */
 549         while (size && *buf) {
 550                 size--;
 551                 buf++;
 552         }
 553         if (!size)
 554                 goto free_return;
 555         buf++; size--;
 556         it = cache_tree();
 557
 558         cp = buf;
 559         it->entry_count = strtol(cp, &ep, 10);
 560         if (cp == ep)
 561                 goto free_return;
 562         cp = ep;
 563         subtree_nr = strtol(cp, &ep, 10);
 564         if (cp == ep)
 565                 goto free_return;
 566         while (size && *buf && *buf != '\n') {
 567                 size--;
 568                 buf++;
 569         }
 570         if (!size)
 571                 goto free_return;
 572         buf++; size--;
 573         if (0 <= it->entry_count) {
 574                 if (size < rawsz)
 575                         goto free_return;
 576                 oidread(&it->oid, (const unsigned char *)buf);
 577                 buf += rawsz;
 578                 size -= rawsz;
 579         }
 580
 581 #if DEBUG_CACHE_TREE
 582         if (0 <= it->entry_count)
 583                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 584                         *buffer, it->entry_count, subtree_nr,
 585                         oid_to_hex(&it->oid));
 586         else
 587                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 588                         *buffer, subtree_nr);
 589 #endif
 590
 591         /*
 592          * Just a heuristic -- we do not add directories that often but
 593          * we do not want to have to extend it immediately when we do,
 594          * hence +2.
 595          */
 596         it->subtree_alloc = subtree_nr + 2;
 597         CALLOC_ARRAY(it->down, it->subtree_alloc);
 598         for (i = 0; i < subtree_nr; i++) {
 599                 /* read each subtree */
 600                 struct cache_tree *sub;
 601                 struct cache_tree_sub *subtree;
 602                 const char *name = buf;
 603
 604                 sub = read_one(&buf, &size);
 605                 if (!sub)
 606                         goto free_return;
 607                 subtree = cache_tree_sub(it, name);
 608                 subtree->cache_tree = sub;
 609         }
 610         if (subtree_nr != it->subtree_nr)
 611                 die("cache-tree: internal error");
 612         *buffer = buf;
 613         *size_p = size;
 614         return it;
 615
 616  free_return:
 617         cache_tree_free(&it);
 618         return NULL;
 619 }
 620
 621 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 622 {
 623         struct cache_tree *result;
 624
 625         if (buffer[0])
 626                 return NULL; /* not the whole tree */
 627
 628         trace2_region_enter("cache_tree", "read", the_repository);
 629         result = read_one(&buffer, &size);
 630         trace2_region_leave("cache_tree", "read", the_repository);
 631
 632         return result;
 633 }
 634
 635 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 636 {
 637         if (!it)
 638                 return NULL;
 639         while (*path) {
 640                 const char *slash;
 641                 struct cache_tree_sub *sub;
 642
 643                 slash = strchrnul(path, '/');
 644                 /*
 645                  * Between path and slash is the name of the subtree
 646                  * to look for.
 647                  */
 648                 sub = find_subtree(it, path, slash - path, 0);
 649                 if (!sub)
 650                         return NULL;
 651                 it = sub->cache_tree;
 652
 653                 path = slash;
 654                 while (*path == '/')
 655                         path++;
 656         }
 657         return it;
 658 }
 659
 660 static int write_index_as_tree_internal(struct object_id *oid,
 661                                         struct index_state *index_state,
 662                                         int cache_tree_valid,
 663                                         int flags,
 664                                         const char *prefix)
 665 {
 666         if (flags & WRITE_TREE_IGNORE_CACHE_TREE) {
 667                 cache_tree_free(&index_state->cache_tree);
 668                 cache_tree_valid = 0;
 669         }
 670
 671         if (!cache_tree_valid && cache_tree_update(index_state, flags) < 0)
 672                 return WRITE_TREE_UNMERGED_INDEX;
 673
 674         if (prefix) {
 675                 struct cache_tree *subtree;
 676                 subtree = cache_tree_find(index_state->cache_tree, prefix);
 677                 if (!subtree)
 678                         return WRITE_TREE_PREFIX_ERROR;
 679                 oidcpy(oid, &subtree->oid);
 680         }
 681         else
 682                 oidcpy(oid, &index_state->cache_tree->oid);
 683
 684         return 0;
 685 }
 686
 687 struct tree* write_in_core_index_as_tree(struct repository *repo) {
 688         struct object_id o;
 689         int was_valid, ret;
 690
 691         struct index_state *index_state = repo->index;
 692         was_valid = index_state->cache_tree &&
 693                     cache_tree_fully_valid(index_state->cache_tree);
 694
 695         ret = write_index_as_tree_internal(&o, index_state, was_valid, 0, NULL);
 696         if (ret == WRITE_TREE_UNMERGED_INDEX) {
 697                 int i;
 698                 bug("there are unmerged index entries:");
 699                 for (i = 0; i < index_state->cache_nr; i++) {
 700                         const struct cache_entry *ce = index_state->cache[i];
 701                         if (ce_stage(ce))
 702                                 bug("%d %.*s", ce_stage(ce),
 703                                     (int)ce_namelen(ce), ce->name);
 704                 }
 705                 BUG("unmerged index entries when writing in-core index");
 706         }
 707
 708         return lookup_tree(repo, &index_state->cache_tree->oid);
 709 }
 710
 711
 712 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 713 {
 714         int entries, was_valid;
 715         struct lock_file lock_file = LOCK_INIT;
 716         int ret;
 717
 718         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 719
 720         entries = read_index_from(index_state, index_path, get_git_dir());
 721         if (entries < 0) {
 722                 ret = WRITE_TREE_UNREADABLE_INDEX;
 723                 goto out;
 724         }
 725
 726         was_valid = !(flags & WRITE_TREE_IGNORE_CACHE_TREE) &&
 727                     index_state->cache_tree &&
 728                     cache_tree_fully_valid(index_state->cache_tree);
 729
 730         ret = write_index_as_tree_internal(oid, index_state, was_valid, flags,
 731                                            prefix);
 732         if (!ret && !was_valid) {
 733                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
 734                 /* Not being able to write is fine -- we are only interested
 735                  * in updating the cache-tree part, and if the next caller
 736                  * ends up using the old index with unupdated cache-tree part
 737                  * it misses the work we did here, but that is just a
 738                  * performance penalty and not a big deal.
 739                  */
 740         }
 741
 742 out:
 743         rollback_lock_file(&lock_file);
 744         return ret;
 745 }
 746
 747 static void prime_cache_tree_sparse_dir(struct cache_tree *it,
 748                                         struct tree *tree)
 749 {
 750
 751         oidcpy(&it->oid, &tree->object.oid);
 752         it->entry_count = 1;
 753 }
 754
 755 static void prime_cache_tree_rec(struct repository *r,
 756                                  struct cache_tree *it,
 757                                  struct tree *tree,
 758                                  struct strbuf *tree_path)
 759 {
 760         struct tree_desc desc;
 761         struct name_entry entry;
 762         int cnt;
 763         size_t base_path_len = tree_path->len;
 764
 765         oidcpy(&it->oid, &tree->object.oid);
 766
 767         init_tree_desc(&desc, tree->buffer, tree->size);
 768         cnt = 0;
 769         while (tree_entry(&desc, &entry)) {
 770                 if (!S_ISDIR(entry.mode))
 771                         cnt++;
 772                 else {
 773                         struct cache_tree_sub *sub;
 774                         struct tree *subtree = lookup_tree(r, &entry.oid);
 775
 776                         if (!subtree->object.parsed)
 777                                 parse_tree(subtree);
 778                         sub = cache_tree_sub(it, entry.path);
 779                         sub->cache_tree = cache_tree();
 780
 781                         /*
 782                          * Recursively-constructed subtree path is only needed when working
 783                          * in a sparse index (where it's used to determine whether the
 784                          * subtree is a sparse directory in the index).
 785                          */
 786                         if (r->index->sparse_index) {
 787                                 strbuf_setlen(tree_path, base_path_len);
 788                                 strbuf_add(tree_path, entry.path, entry.pathlen);
 789                                 strbuf_addch(tree_path, '/');
 790                         }
 791
 792                         /*
 793                          * If a sparse index is in use, the directory being processed may be
 794                          * sparse. To confirm that, we can check whether an entry with that
 795                          * exact name exists in the index. If it does, the created subtree
 796                          * should be sparse. Otherwise, cache tree expansion should continue
 797                          * as normal.
 798                          */
 799                         if (r->index->sparse_index &&
 800                             index_entry_exists(r->index, tree_path->buf, tree_path->len))
 801                                 prime_cache_tree_sparse_dir(sub->cache_tree, subtree);
 802                         else
 803                                 prime_cache_tree_rec(r, sub->cache_tree, subtree, tree_path);
 804                         cnt += sub->cache_tree->entry_count;
 805                 }
 806         }
 807
 808         it->entry_count = cnt;
 809 }
 810
 811 void prime_cache_tree(struct repository *r,
 812                       struct index_state *istate,
 813                       struct tree *tree)
 814 {
 815         struct strbuf tree_path = STRBUF_INIT;
 816
 817         trace2_region_enter("cache-tree", "prime_cache_tree", the_repository);
 818         cache_tree_free(&istate->cache_tree);
 819         istate->cache_tree = cache_tree();
 820
 821         prime_cache_tree_rec(r, istate->cache_tree, tree, &tree_path);
 822         strbuf_release(&tree_path);
 823         istate->cache_changed |= CACHE_TREE_CHANGED;
 824         trace2_region_leave("cache-tree", "prime_cache_tree", the_repository);
 825 }
 826
 827 /*
 828  * find the cache_tree that corresponds to the current level without
 829  * exploding the full path into textual form.  The root of the
 830  * cache tree is given as "root", and our current level is "info".
 831  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 832  * (2) Otherwise, find the cache_tree that corresponds to one level
 833  *     above us, and find ourselves in there.
 834  */
 835 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 836                                                          struct traverse_info *info)
 837 {
 838         struct cache_tree *our_parent;
 839
 840         if (!info->prev)
 841                 return root;
 842         our_parent = find_cache_tree_from_traversal(root, info->prev);
 843         return cache_tree_find(our_parent, info->name);
 844 }
 845
 846 int cache_tree_matches_traversal(struct cache_tree *root,
 847                                  struct name_entry *ent,
 848                                  struct traverse_info *info)
 849 {
 850         struct cache_tree *it;
 851
 852         it = find_cache_tree_from_traversal(root, info);
 853         it = cache_tree_find(it, ent->path);
 854         if (it && it->entry_count > 0 && oideq(&ent->oid, &it->oid))
 855                 return it->entry_count;
 856         return 0;
 857 }
 858
 859 static void verify_one_sparse(struct index_state *istate,
 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(istate, 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, OBJ_TREE,
 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 }