cache-tree.c

   1 #include "cache.h"
   2 #include "alloc.h"
   3 #include "environment.h"
   4 #include "hex.h"
   5 #include "lockfile.h"
   6 #include "tree.h"
   7 #include "tree-walk.h"
   8 #include "cache-tree.h"
   9 #include "bulk-checkin.h"
  10 #include "object-store.h"
  11 #include "replace-object.h"
  12 #include "promisor-remote.h"
  13 #include "sparse-index.h"
  14
  15 #ifndef DEBUG_CACHE_TREE
  16 #define DEBUG_CACHE_TREE 0
  17 #endif
  18
  19 struct cache_tree *cache_tree(void)
  20 {
  21         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  22         it->entry_count = -1;
  23         return it;
  24 }
  25
  26 void cache_tree_free(struct cache_tree **it_p)
  27 {
  28         int i;
  29         struct cache_tree *it = *it_p;
  30
  31         if (!it)
  32                 return;
  33         for (i = 0; i < it->subtree_nr; i++)
  34                 if (it->down[i]) {
  35                         cache_tree_free(&it->down[i]->cache_tree);
  36                         free(it->down[i]);
  37                 }
  38         free(it->down);
  39         free(it);
  40         *it_p = NULL;
  41 }
  42
  43 static int subtree_name_cmp(const char *one, int onelen,
  44                             const char *two, int twolen)
  45 {
  46         if (onelen < twolen)
  47                 return -1;
  48         if (twolen < onelen)
  49                 return 1;
  50         return memcmp(one, two, onelen);
  51 }
  52
  53 int cache_tree_subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  54 {
  55         struct cache_tree_sub **down = it->down;
  56         int lo, hi;
  57         lo = 0;
  58         hi = it->subtree_nr;
  59         while (lo < hi) {
  60                 int mi = lo + (hi - lo) / 2;
  61                 struct cache_tree_sub *mdl = down[mi];
  62                 int cmp = subtree_name_cmp(path, pathlen,
  63                                            mdl->name, mdl->namelen);
  64                 if (!cmp)
  65                         return mi;
  66                 if (cmp < 0)
  67                         hi = mi;
  68                 else
  69                         lo = mi + 1;
  70         }
  71         return -lo-1;
  72 }
  73
  74 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  75                                            const char *path,
  76                                            int pathlen,
  77                                            int create)
  78 {
  79         struct cache_tree_sub *down;
  80         int pos = cache_tree_subtree_pos(it, path, pathlen);
  81         if (0 <= pos)
  82                 return it->down[pos];
  83         if (!create)
  84                 return NULL;
  85
  86         pos = -pos-1;
  87         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
  88         it->subtree_nr++;
  89
  90         FLEX_ALLOC_MEM(down, name, path, pathlen);
  91         down->cache_tree = NULL;
  92         down->namelen = pathlen;
  93
  94         if (pos < it->subtree_nr)
  95                 MOVE_ARRAY(it->down + pos + 1, it->down + pos,
  96                            it->subtree_nr - pos - 1);
  97         it->down[pos] = down;
  98         return down;
  99 }
 100
 101 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
 102 {
 103         int pathlen = strlen(path);
 104         return find_subtree(it, path, pathlen, 1);
 105 }
 106
 107 static int do_invalidate_path(struct cache_tree *it, const char *path)
 108 {
 109         /* a/b/c
 110          * ==> invalidate self
 111          * ==> find "a", have it invalidate "b/c"
 112          * a
 113          * ==> invalidate self
 114          * ==> if "a" exists as a subtree, remove it.
 115          */
 116         const char *slash;
 117         int namelen;
 118         struct cache_tree_sub *down;
 119
 120 #if DEBUG_CACHE_TREE
 121         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 122 #endif
 123
 124         if (!it)
 125                 return 0;
 126         slash = strchrnul(path, '/');
 127         namelen = slash - path;
 128         it->entry_count = -1;
 129         if (!*slash) {
 130                 int pos;
 131                 pos = cache_tree_subtree_pos(it, path, namelen);
 132                 if (0 <= pos) {
 133                         cache_tree_free(&it->down[pos]->cache_tree);
 134                         free(it->down[pos]);
 135                         /* 0 1 2 3 4 5
 136                          *       ^     ^subtree_nr = 6
 137                          *       pos
 138                          * move 4 and 5 up one place (2 entries)
 139                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 140                          */
 141                         MOVE_ARRAY(it->down + pos, it->down + pos + 1,
 142                                    it->subtree_nr - pos - 1);
 143                         it->subtree_nr--;
 144                 }
 145                 return 1;
 146         }
 147         down = find_subtree(it, path, namelen, 0);
 148         if (down)
 149                 do_invalidate_path(down->cache_tree, slash + 1);
 150         return 1;
 151 }
 152
 153 void cache_tree_invalidate_path(struct index_state *istate, const char *path)
 154 {
 155         if (do_invalidate_path(istate->cache_tree, path))
 156                 istate->cache_changed |= CACHE_TREE_CHANGED;
 157 }
 158
 159 static int verify_cache(struct index_state *istate, int flags)
 160 {
 161         unsigned i, funny;
 162         int silent = flags & WRITE_TREE_SILENT;
 163
 164         /* Verify that the tree is merged */
 165         funny = 0;
 166         for (i = 0; i < istate->cache_nr; i++) {
 167                 const struct cache_entry *ce = istate->cache[i];
 168                 if (ce_stage(ce)) {
 169                         if (silent)
 170                                 return -1;
 171                         if (10 < ++funny) {
 172                                 fprintf(stderr, "...\n");
 173                                 break;
 174                         }
 175                         fprintf(stderr, "%s: unmerged (%s)\n",
 176                                 ce->name, oid_to_hex(&ce->oid));
 177                 }
 178         }
 179         if (funny)
 180                 return -1;
 181
 182         /* Also verify that the cache does not have path and path/file
 183          * at the same time.  At this point we know the cache has only
 184          * stage 0 entries.
 185          */
 186         funny = 0;
 187         for (i = 0; i + 1 < istate->cache_nr; i++) {
 188                 /* path/file always comes after path because of the way
 189                  * the cache is sorted.  Also path can appear only once,
 190                  * which means conflicting one would immediately follow.
 191                  */
 192                 const struct cache_entry *this_ce = istate->cache[i];
 193                 const struct cache_entry *next_ce = istate->cache[i + 1];
 194                 const char *this_name = this_ce->name;
 195                 const char *next_name = next_ce->name;
 196                 int this_len = ce_namelen(this_ce);
 197                 if (this_len < ce_namelen(next_ce) &&
 198                     next_name[this_len] == '/' &&
 199                     strncmp(this_name, next_name, this_len) == 0) {
 200                         if (10 < ++funny) {
 201                                 fprintf(stderr, "...\n");
 202                                 break;
 203                         }
 204                         fprintf(stderr, "You have both %s and %s\n",
 205                                 this_name, next_name);
 206                 }
 207         }
 208         if (funny)
 209                 return -1;
 210         return 0;
 211 }
 212
 213 static void discard_unused_subtrees(struct cache_tree *it)
 214 {
 215         struct cache_tree_sub **down = it->down;
 216         int nr = it->subtree_nr;
 217         int dst, src;
 218         for (dst = src = 0; src < nr; src++) {
 219                 struct cache_tree_sub *s = down[src];
 220                 if (s->used)
 221                         down[dst++] = s;
 222                 else {
 223                         cache_tree_free(&s->cache_tree);
 224                         free(s);
 225                         it->subtree_nr--;
 226                 }
 227         }
 228 }
 229
 230 int cache_tree_fully_valid(struct cache_tree *it)
 231 {
 232         int i;
 233         if (!it)
 234                 return 0;
 235         if (it->entry_count < 0 || !has_object_file(&it->oid))
 236                 return 0;
 237         for (i = 0; i < it->subtree_nr; i++) {
 238                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 239                         return 0;
 240         }
 241         return 1;
 242 }
 243
 244 static int must_check_existence(const struct cache_entry *ce)
 245 {
 246         return !(has_promisor_remote() && ce_skip_worktree(ce));
 247 }
 248
 249 static int update_one(struct cache_tree *it,
 250                       struct cache_entry **cache,
 251                       int entries,
 252                       const char *base,
 253                       int baselen,
 254                       int *skip_count,
 255                       int flags)
 256 {
 257         struct strbuf buffer;
 258         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 259         int dryrun = flags & WRITE_TREE_DRY_RUN;
 260         int repair = flags & WRITE_TREE_REPAIR;
 261         int to_invalidate = 0;
 262         int i;
 263
 264         assert(!(dryrun && repair));
 265
 266         *skip_count = 0;
 267
 268         /*
 269          * If the first entry of this region is a sparse directory
 270          * entry corresponding exactly to 'base', then this cache_tree
 271          * struct is a "leaf" in the data structure, pointing to the
 272          * tree OID specified in the entry.
 273          */
 274         if (entries > 0) {
 275                 const struct cache_entry *ce = cache[0];
 276
 277                 if (S_ISSPARSEDIR(ce->ce_mode) &&
 278                     ce->ce_namelen == baselen &&
 279                     !strncmp(ce->name, base, baselen)) {
 280                         it->entry_count = 1;
 281                         oidcpy(&it->oid, &ce->oid);
 282                         return 1;
 283                 }
 284         }
 285
 286         if (0 <= it->entry_count && has_object_file(&it->oid))
 287                 return it->entry_count;
 288
 289         /*
 290          * We first scan for subtrees and update them; we start by
 291          * marking existing subtrees -- the ones that are unmarked
 292          * should not be in the result.
 293          */
 294         for (i = 0; i < it->subtree_nr; i++)
 295                 it->down[i]->used = 0;
 296
 297         /*
 298          * Find the subtrees and update them.
 299          */
 300         i = 0;
 301         while (i < entries) {
 302                 const struct cache_entry *ce = cache[i];
 303                 struct cache_tree_sub *sub;
 304                 const char *path, *slash;
 305                 int pathlen, sublen, subcnt, subskip;
 306
 307                 path = ce->name;
 308                 pathlen = ce_namelen(ce);
 309                 if (pathlen <= baselen || memcmp(base, path, baselen))
 310                         break; /* at the end of this level */
 311
 312                 slash = strchr(path + baselen, '/');
 313                 if (!slash) {
 314                         i++;
 315                         continue;
 316                 }
 317                 /*
 318                  * a/bbb/c (base = a/, slash = /c)
 319                  * ==>
 320                  * path+baselen = bbb/c, sublen = 3
 321                  */
 322                 sublen = slash - (path + baselen);
 323                 sub = find_subtree(it, path + baselen, sublen, 1);
 324                 if (!sub->cache_tree)
 325                         sub->cache_tree = cache_tree();
 326                 subcnt = update_one(sub->cache_tree,
 327                                     cache + i, entries - i,
 328                                     path,
 329                                     baselen + sublen + 1,
 330                                     &subskip,
 331                                     flags);
 332                 if (subcnt < 0)
 333                         return subcnt;
 334                 if (!subcnt)
 335                         die("index cache-tree records empty sub-tree");
 336                 i += subcnt;
 337                 sub->count = subcnt; /* to be used in the next loop */
 338                 *skip_count += subskip;
 339                 sub->used = 1;
 340         }
 341
 342         discard_unused_subtrees(it);
 343
 344         /*
 345          * Then write out the tree object for this level.
 346          */
 347         strbuf_init(&buffer, 8192);
 348
 349         i = 0;
 350         while (i < entries) {
 351                 const struct cache_entry *ce = cache[i];
 352                 struct cache_tree_sub *sub = NULL;
 353                 const char *path, *slash;
 354                 int pathlen, entlen;
 355                 const struct object_id *oid;
 356                 unsigned mode;
 357                 int expected_missing = 0;
 358                 int contains_ita = 0;
 359                 int ce_missing_ok;
 360
 361                 path = ce->name;
 362                 pathlen = ce_namelen(ce);
 363                 if (pathlen <= baselen || memcmp(base, path, baselen))
 364                         break; /* at the end of this level */
 365
 366                 slash = strchr(path + baselen, '/');
 367                 if (slash) {
 368                         entlen = slash - (path + baselen);
 369                         sub = find_subtree(it, path + baselen, entlen, 0);
 370                         if (!sub)
 371                                 die("cache-tree.c: '%.*s' in '%s' not found",
 372                                     entlen, path + baselen, path);
 373                         i += sub->count;
 374                         oid = &sub->cache_tree->oid;
 375                         mode = S_IFDIR;
 376                         contains_ita = sub->cache_tree->entry_count < 0;
 377                         if (contains_ita) {
 378                                 to_invalidate = 1;
 379                                 expected_missing = 1;
 380                         }
 381                 }
 382                 else {
 383                         oid = &ce->oid;
 384                         mode = ce->ce_mode;
 385                         entlen = pathlen - baselen;
 386                         i++;
 387                 }
 388
 389                 ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
 390                         !must_check_existence(ce);
 391                 if (is_null_oid(oid) ||
 392                     (!ce_missing_ok && !has_object_file(oid))) {
 393                         strbuf_release(&buffer);
 394                         if (expected_missing)
 395                                 return -1;
 396                         return error("invalid object %06o %s for '%.*s'",
 397                                 mode, oid_to_hex(oid), entlen+baselen, path);
 398                 }
 399
 400                 /*
 401                  * CE_REMOVE entries are removed before the index is
 402                  * written to disk. Skip them to remain consistent
 403                  * with the future on-disk index.
 404                  */
 405                 if (ce->ce_flags & CE_REMOVE) {
 406                         *skip_count = *skip_count + 1;
 407                         continue;
 408                 }
 409
 410                 /*
 411                  * CE_INTENT_TO_ADD entries exist in on-disk index but
 412                  * they are not part of generated trees. Invalidate up
 413                  * to root to force cache-tree users to read elsewhere.
 414                  */
 415                 if (!sub && ce_intent_to_add(ce)) {
 416                         to_invalidate = 1;
 417                         continue;
 418                 }
 419
 420                 /*
 421                  * "sub" can be an empty tree if all subentries are i-t-a.
 422                  */
 423                 if (contains_ita && is_empty_tree_oid(oid))
 424                         continue;
 425
 426                 strbuf_grow(&buffer, entlen + 100);
 427                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 428                 strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
 429
 430 #if DEBUG_CACHE_TREE
 431                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 432                         mode, entlen, path + baselen);
 433 #endif
 434         }
 435
 436         if (repair) {
 437                 struct object_id oid;
 438                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 439                                  OBJ_TREE, &oid);
 440                 if (has_object_file_with_flags(&oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 441                         oidcpy(&it->oid, &oid);
 442                 else
 443                         to_invalidate = 1;
 444         } else if (dryrun) {
 445                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 446                                  OBJ_TREE, &it->oid);
 447         } else if (write_object_file_flags(buffer.buf, buffer.len, OBJ_TREE,
 448                                            &it->oid, flags & WRITE_TREE_SILENT
 449                                            ? HASH_SILENT : 0)) {
 450                 strbuf_release(&buffer);
 451                 return -1;
 452         }
 453
 454         strbuf_release(&buffer);
 455         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 456 #if DEBUG_CACHE_TREE
 457         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 458                 it->entry_count, it->subtree_nr,
 459                 oid_to_hex(&it->oid));
 460 #endif
 461         return i;
 462 }
 463
 464 int cache_tree_update(struct index_state *istate, int flags)
 465 {
 466         int skip, i;
 467
 468         i = verify_cache(istate, flags);
 469
 470         if (i)
 471                 return i;
 472
 473         if (!istate->cache_tree)
 474                 istate->cache_tree = cache_tree();
 475
 476         if (!(flags & WRITE_TREE_MISSING_OK) && has_promisor_remote())
 477                 prefetch_cache_entries(istate, must_check_existence);
 478
 479         trace_performance_enter();
 480         trace2_region_enter("cache_tree", "update", the_repository);
 481         begin_odb_transaction();
 482         i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
 483                        "", 0, &skip, flags);
 484         end_odb_transaction();
 485         trace2_region_leave("cache_tree", "update", the_repository);
 486         trace_performance_leave("cache_tree_update");
 487         if (i < 0)
 488                 return i;
 489         istate->cache_changed |= CACHE_TREE_CHANGED;
 490         return 0;
 491 }
 492
 493 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 494                       const char *path, int pathlen)
 495 {
 496         int i;
 497
 498         /* One "cache-tree" entry consists of the following:
 499          * path (NUL terminated)
 500          * entry_count, subtree_nr ("%d %d\n")
 501          * tree-sha1 (missing if invalid)
 502          * subtree_nr "cache-tree" entries for subtrees.
 503          */
 504         strbuf_grow(buffer, pathlen + 100);
 505         strbuf_add(buffer, path, pathlen);
 506         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 507
 508 #if DEBUG_CACHE_TREE
 509         if (0 <= it->entry_count)
 510                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 511                         pathlen, path, it->entry_count, it->subtree_nr,
 512                         oid_to_hex(&it->oid));
 513         else
 514                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 515                         pathlen, path, it->subtree_nr);
 516 #endif
 517
 518         if (0 <= it->entry_count) {
 519                 strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
 520         }
 521         for (i = 0; i < it->subtree_nr; i++) {
 522                 struct cache_tree_sub *down = it->down[i];
 523                 if (i) {
 524                         struct cache_tree_sub *prev = it->down[i-1];
 525                         if (subtree_name_cmp(down->name, down->namelen,
 526                                              prev->name, prev->namelen) <= 0)
 527                                 die("fatal - unsorted cache subtree");
 528                 }
 529                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 530         }
 531 }
 532
 533 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 534 {
 535         trace2_region_enter("cache_tree", "write", the_repository);
 536         write_one(sb, root, "", 0);
 537         trace2_region_leave("cache_tree", "write", the_repository);
 538 }
 539
 540 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 541 {
 542         const char *buf = *buffer;
 543         unsigned long size = *size_p;
 544         const char *cp;
 545         char *ep;
 546         struct cache_tree *it;
 547         int i, subtree_nr;
 548         const unsigned rawsz = the_hash_algo->rawsz;
 549
 550         it = NULL;
 551         /* skip name, but make sure name exists */
 552         while (size && *buf) {
 553                 size--;
 554                 buf++;
 555         }
 556         if (!size)
 557                 goto free_return;
 558         buf++; size--;
 559         it = cache_tree();
 560
 561         cp = buf;
 562         it->entry_count = strtol(cp, &ep, 10);
 563         if (cp == ep)
 564                 goto free_return;
 565         cp = ep;
 566         subtree_nr = strtol(cp, &ep, 10);
 567         if (cp == ep)
 568                 goto free_return;
 569         while (size && *buf && *buf != '\n') {
 570                 size--;
 571                 buf++;
 572         }
 573         if (!size)
 574                 goto free_return;
 575         buf++; size--;
 576         if (0 <= it->entry_count) {
 577                 if (size < rawsz)
 578                         goto free_return;
 579                 oidread(&it->oid, (const unsigned char *)buf);
 580                 buf += rawsz;
 581                 size -= rawsz;
 582         }
 583
 584 #if DEBUG_CACHE_TREE
 585         if (0 <= it->entry_count)
 586                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 587                         *buffer, it->entry_count, subtree_nr,
 588                         oid_to_hex(&it->oid));
 589         else
 590                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 591                         *buffer, subtree_nr);
 592 #endif
 593
 594         /*
 595          * Just a heuristic -- we do not add directories that often but
 596          * we do not want to have to extend it immediately when we do,
 597          * hence +2.
 598          */
 599         it->subtree_alloc = subtree_nr + 2;
 600         CALLOC_ARRAY(it->down, it->subtree_alloc);
 601         for (i = 0; i < subtree_nr; i++) {
 602                 /* read each subtree */
 603                 struct cache_tree *sub;
 604                 struct cache_tree_sub *subtree;
 605                 const char *name = buf;
 606
 607                 sub = read_one(&buf, &size);
 608                 if (!sub)
 609                         goto free_return;
 610                 subtree = cache_tree_sub(it, name);
 611                 subtree->cache_tree = sub;
 612         }
 613         if (subtree_nr != it->subtree_nr)
 614                 die("cache-tree: internal error");
 615         *buffer = buf;
 616         *size_p = size;
 617         return it;
 618
 619  free_return:
 620         cache_tree_free(&it);
 621         return NULL;
 622 }
 623
 624 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 625 {
 626         struct cache_tree *result;
 627
 628         if (buffer[0])
 629                 return NULL; /* not the whole tree */
 630
 631         trace2_region_enter("cache_tree", "read", the_repository);
 632         result = read_one(&buffer, &size);
 633         trace2_region_leave("cache_tree", "read", the_repository);
 634
 635         return result;
 636 }
 637
 638 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 639 {
 640         if (!it)
 641                 return NULL;
 642         while (*path) {
 643                 const char *slash;
 644                 struct cache_tree_sub *sub;
 645
 646                 slash = strchrnul(path, '/');
 647                 /*
 648                  * Between path and slash is the name of the subtree
 649                  * to look for.
 650                  */
 651                 sub = find_subtree(it, path, slash - path, 0);
 652                 if (!sub)
 653                         return NULL;
 654                 it = sub->cache_tree;
 655
 656                 path = slash;
 657                 while (*path == '/')
 658                         path++;
 659         }
 660         return it;
 661 }
 662
 663 static int write_index_as_tree_internal(struct object_id *oid,
 664                                         struct index_state *index_state,
 665                                         int cache_tree_valid,
 666                                         int flags,
 667                                         const char *prefix)
 668 {
 669         if (flags & WRITE_TREE_IGNORE_CACHE_TREE) {
 670                 cache_tree_free(&index_state->cache_tree);
 671                 cache_tree_valid = 0;
 672         }
 673
 674         if (!cache_tree_valid && cache_tree_update(index_state, flags) < 0)
 675                 return WRITE_TREE_UNMERGED_INDEX;
 676
 677         if (prefix) {
 678                 struct cache_tree *subtree;
 679                 subtree = cache_tree_find(index_state->cache_tree, prefix);
 680                 if (!subtree)
 681                         return WRITE_TREE_PREFIX_ERROR;
 682                 oidcpy(oid, &subtree->oid);
 683         }
 684         else
 685                 oidcpy(oid, &index_state->cache_tree->oid);
 686
 687         return 0;
 688 }
 689
 690 struct tree* write_in_core_index_as_tree(struct repository *repo) {
 691         struct object_id o;
 692         int was_valid, ret;
 693
 694         struct index_state *index_state = repo->index;
 695         was_valid = index_state->cache_tree &&
 696                     cache_tree_fully_valid(index_state->cache_tree);
 697
 698         ret = write_index_as_tree_internal(&o, index_state, was_valid, 0, NULL);
 699         if (ret == WRITE_TREE_UNMERGED_INDEX) {
 700                 int i;
 701                 bug("there are unmerged index entries:");
 702                 for (i = 0; i < index_state->cache_nr; i++) {
 703                         const struct cache_entry *ce = index_state->cache[i];
 704                         if (ce_stage(ce))
 705                                 bug("%d %.*s", ce_stage(ce),
 706                                     (int)ce_namelen(ce), ce->name);
 707                 }
 708                 BUG("unmerged index entries when writing in-core index");
 709         }
 710
 711         return lookup_tree(repo, &index_state->cache_tree->oid);
 712 }
 713
 714
 715 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 716 {
 717         int entries, was_valid;
 718         struct lock_file lock_file = LOCK_INIT;
 719         int ret;
 720
 721         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 722
 723         entries = read_index_from(index_state, index_path, get_git_dir());
 724         if (entries < 0) {
 725                 ret = WRITE_TREE_UNREADABLE_INDEX;
 726                 goto out;
 727         }
 728
 729         was_valid = !(flags & WRITE_TREE_IGNORE_CACHE_TREE) &&
 730                     index_state->cache_tree &&
 731                     cache_tree_fully_valid(index_state->cache_tree);
 732
 733         ret = write_index_as_tree_internal(oid, index_state, was_valid, flags,
 734                                            prefix);
 735         if (!ret && !was_valid) {
 736                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
 737                 /* Not being able to write is fine -- we are only interested
 738                  * in updating the cache-tree part, and if the next caller
 739                  * ends up using the old index with unupdated cache-tree part
 740                  * it misses the work we did here, but that is just a
 741                  * performance penalty and not a big deal.
 742                  */
 743         }
 744
 745 out:
 746         rollback_lock_file(&lock_file);
 747         return ret;
 748 }
 749
 750 static void prime_cache_tree_sparse_dir(struct cache_tree *it,
 751                                         struct tree *tree)
 752 {
 753
 754         oidcpy(&it->oid, &tree->object.oid);
 755         it->entry_count = 1;
 756 }
 757
 758 static void prime_cache_tree_rec(struct repository *r,
 759                                  struct cache_tree *it,
 760                                  struct tree *tree,
 761                                  struct strbuf *tree_path)
 762 {
 763         struct tree_desc desc;
 764         struct name_entry entry;
 765         int cnt;
 766         size_t base_path_len = tree_path->len;
 767
 768         oidcpy(&it->oid, &tree->object.oid);
 769
 770         init_tree_desc(&desc, tree->buffer, tree->size);
 771         cnt = 0;
 772         while (tree_entry(&desc, &entry)) {
 773                 if (!S_ISDIR(entry.mode))
 774                         cnt++;
 775                 else {
 776                         struct cache_tree_sub *sub;
 777                         struct tree *subtree = lookup_tree(r, &entry.oid);
 778
 779                         if (!subtree->object.parsed)
 780                                 parse_tree(subtree);
 781                         sub = cache_tree_sub(it, entry.path);
 782                         sub->cache_tree = cache_tree();
 783
 784                         /*
 785                          * Recursively-constructed subtree path is only needed when working
 786                          * in a sparse index (where it's used to determine whether the
 787                          * subtree is a sparse directory in the index).
 788                          */
 789                         if (r->index->sparse_index) {
 790                                 strbuf_setlen(tree_path, base_path_len);
 791                                 strbuf_add(tree_path, entry.path, entry.pathlen);
 792                                 strbuf_addch(tree_path, '/');
 793                         }
 794
 795                         /*
 796                          * If a sparse index is in use, the directory being processed may be
 797                          * sparse. To confirm that, we can check whether an entry with that
 798                          * exact name exists in the index. If it does, the created subtree
 799                          * should be sparse. Otherwise, cache tree expansion should continue
 800                          * as normal.
 801                          */
 802                         if (r->index->sparse_index &&
 803                             index_entry_exists(r->index, tree_path->buf, tree_path->len))
 804                                 prime_cache_tree_sparse_dir(sub->cache_tree, subtree);
 805                         else
 806                                 prime_cache_tree_rec(r, sub->cache_tree, subtree, tree_path);
 807                         cnt += sub->cache_tree->entry_count;
 808                 }
 809         }
 810
 811         it->entry_count = cnt;
 812 }
 813
 814 void prime_cache_tree(struct repository *r,
 815                       struct index_state *istate,
 816                       struct tree *tree)
 817 {
 818         struct strbuf tree_path = STRBUF_INIT;
 819
 820         trace2_region_enter("cache-tree", "prime_cache_tree", the_repository);
 821         cache_tree_free(&istate->cache_tree);
 822         istate->cache_tree = cache_tree();
 823
 824         prime_cache_tree_rec(r, istate->cache_tree, tree, &tree_path);
 825         strbuf_release(&tree_path);
 826         istate->cache_changed |= CACHE_TREE_CHANGED;
 827         trace2_region_leave("cache-tree", "prime_cache_tree", the_repository);
 828 }
 829
 830 /*
 831  * find the cache_tree that corresponds to the current level without
 832  * exploding the full path into textual form.  The root of the
 833  * cache tree is given as "root", and our current level is "info".
 834  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 835  * (2) Otherwise, find the cache_tree that corresponds to one level
 836  *     above us, and find ourselves in there.
 837  */
 838 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 839                                                          struct traverse_info *info)
 840 {
 841         struct cache_tree *our_parent;
 842
 843         if (!info->prev)
 844                 return root;
 845         our_parent = find_cache_tree_from_traversal(root, info->prev);
 846         return cache_tree_find(our_parent, info->name);
 847 }
 848
 849 int cache_tree_matches_traversal(struct cache_tree *root,
 850                                  struct name_entry *ent,
 851                                  struct traverse_info *info)
 852 {
 853         struct cache_tree *it;
 854
 855         it = find_cache_tree_from_traversal(root, info);
 856         it = cache_tree_find(it, ent->path);
 857         if (it && it->entry_count > 0 && oideq(&ent->oid, &it->oid))
 858                 return it->entry_count;
 859         return 0;
 860 }
 861
 862 static void verify_one_sparse(struct index_state *istate,
 863                               struct strbuf *path,
 864                               int pos)
 865 {
 866         struct cache_entry *ce = istate->cache[pos];
 867
 868         if (!S_ISSPARSEDIR(ce->ce_mode))
 869                 BUG("directory '%s' is present in index, but not sparse",
 870                     path->buf);
 871 }
 872
 873 /*
 874  * Returns:
 875  *  0 - Verification completed.
 876  *  1 - Restart verification - a call to ensure_full_index() freed the cache
 877  *      tree that is being verified and verification needs to be restarted from
 878  *      the new toplevel cache tree.
 879  */
 880 static int verify_one(struct repository *r,
 881                       struct index_state *istate,
 882                       struct cache_tree *it,
 883                       struct strbuf *path)
 884 {
 885         int i, pos, len = path->len;
 886         struct strbuf tree_buf = STRBUF_INIT;
 887         struct object_id new_oid;
 888
 889         for (i = 0; i < it->subtree_nr; i++) {
 890                 strbuf_addf(path, "%s/", it->down[i]->name);
 891                 if (verify_one(r, istate, it->down[i]->cache_tree, path))
 892                         return 1;
 893                 strbuf_setlen(path, len);
 894         }
 895
 896         if (it->entry_count < 0 ||
 897             /* no verification on tests (t7003) that replace trees */
 898             lookup_replace_object(r, &it->oid) != &it->oid)
 899                 return 0;
 900
 901         if (path->len) {
 902                 /*
 903                  * If the index is sparse and the cache tree is not
 904                  * index_name_pos() may trigger ensure_full_index() which will
 905                  * free the tree that is being verified.
 906                  */
 907                 int is_sparse = istate->sparse_index;
 908                 pos = index_name_pos(istate, path->buf, path->len);
 909                 if (is_sparse && !istate->sparse_index)
 910                         return 1;
 911
 912                 if (pos >= 0) {
 913                         verify_one_sparse(istate, path, pos);
 914                         return 0;
 915                 }
 916
 917                 pos = -pos - 1;
 918         } else {
 919                 pos = 0;
 920         }
 921
 922         i = 0;
 923         while (i < it->entry_count) {
 924                 struct cache_entry *ce = istate->cache[pos + i];
 925                 const char *slash;
 926                 struct cache_tree_sub *sub = NULL;
 927                 const struct object_id *oid;
 928                 const char *name;
 929                 unsigned mode;
 930                 int entlen;
 931
 932                 if (ce->ce_flags & (CE_STAGEMASK | CE_INTENT_TO_ADD | CE_REMOVE))
 933                         BUG("%s with flags 0x%x should not be in cache-tree",
 934                             ce->name, ce->ce_flags);
 935                 name = ce->name + path->len;
 936                 slash = strchr(name, '/');
 937                 if (slash) {
 938                         entlen = slash - name;
 939                         sub = find_subtree(it, ce->name + path->len, entlen, 0);
 940                         if (!sub || sub->cache_tree->entry_count < 0)
 941                                 BUG("bad subtree '%.*s'", entlen, name);
 942                         oid = &sub->cache_tree->oid;
 943                         mode = S_IFDIR;
 944                         i += sub->cache_tree->entry_count;
 945                 } else {
 946                         oid = &ce->oid;
 947                         mode = ce->ce_mode;
 948                         entlen = ce_namelen(ce) - path->len;
 949                         i++;
 950                 }
 951                 strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
 952                 strbuf_add(&tree_buf, oid->hash, r->hash_algo->rawsz);
 953         }
 954         hash_object_file(r->hash_algo, tree_buf.buf, tree_buf.len, OBJ_TREE,
 955                          &new_oid);
 956         if (!oideq(&new_oid, &it->oid))
 957                 BUG("cache-tree for path %.*s does not match. "
 958                     "Expected %s got %s", len, path->buf,
 959                     oid_to_hex(&new_oid), oid_to_hex(&it->oid));
 960         strbuf_setlen(path, len);
 961         strbuf_release(&tree_buf);
 962         return 0;
 963 }
 964
 965 void cache_tree_verify(struct repository *r, struct index_state *istate)
 966 {
 967         struct strbuf path = STRBUF_INIT;
 968
 969         if (!istate->cache_tree)
 970                 return;
 971         if (verify_one(r, istate, istate->cache_tree, &path)) {
 972                 strbuf_reset(&path);
 973                 if (verify_one(r, istate, istate->cache_tree, &path))
 974                         BUG("ensure_full_index() called twice while verifying cache tree");
 975         }
 976         strbuf_release(&path);
 977 }