cache-tree.c

   1 #include "git-compat-util.h"
   2 #include "environment.h"
   3 #include "hex.h"
   4 #include "lockfile.h"
   5 #include "tree.h"
   6 #include "tree-walk.h"
   7 #include "cache-tree.h"
   8 #include "bulk-checkin.h"
   9 #include "object-file.h"
  10 #include "object-store-ll.h"
  11 #include "read-cache-ll.h"
  12 #include "replace-object.h"
  13 #include "promisor-remote.h"
  14 #include "trace.h"
  15 #include "trace2.h"
  16
  17 #ifndef DEBUG_CACHE_TREE
  18 #define DEBUG_CACHE_TREE 0
  19 #endif
  20
  21 struct cache_tree *cache_tree(void)
  22 {
  23         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  24         it->entry_count = -1;
  25         return it;
  26 }
  27
  28 void cache_tree_free(struct cache_tree **it_p)
  29 {
  30         int i;
  31         struct cache_tree *it = *it_p;
  32
  33         if (!it)
  34                 return;
  35         for (i = 0; i < it->subtree_nr; i++)
  36                 if (it->down[i]) {
  37                         cache_tree_free(&it->down[i]->cache_tree);
  38                         free(it->down[i]);
  39                 }
  40         free(it->down);
  41         free(it);
  42         *it_p = NULL;
  43 }
  44
  45 static int subtree_name_cmp(const char *one, int onelen,
  46                             const char *two, int twolen)
  47 {
  48         if (onelen < twolen)
  49                 return -1;
  50         if (twolen < onelen)
  51                 return 1;
  52         return memcmp(one, two, onelen);
  53 }
  54
  55 int cache_tree_subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  56 {
  57         struct cache_tree_sub **down = it->down;
  58         int lo, hi;
  59         lo = 0;
  60         hi = it->subtree_nr;
  61         while (lo < hi) {
  62                 int mi = lo + (hi - lo) / 2;
  63                 struct cache_tree_sub *mdl = down[mi];
  64                 int cmp = subtree_name_cmp(path, pathlen,
  65                                            mdl->name, mdl->namelen);
  66                 if (!cmp)
  67                         return mi;
  68                 if (cmp < 0)
  69                         hi = mi;
  70                 else
  71                         lo = mi + 1;
  72         }
  73         return -lo-1;
  74 }
  75
  76 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  77                                            const char *path,
  78                                            int pathlen,
  79                                            int create)
  80 {
  81         struct cache_tree_sub *down;
  82         int pos = cache_tree_subtree_pos(it, path, pathlen);
  83         if (0 <= pos)
  84                 return it->down[pos];
  85         if (!create)
  86                 return NULL;
  87
  88         pos = -pos-1;
  89         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
  90         it->subtree_nr++;
  91
  92         FLEX_ALLOC_MEM(down, name, path, pathlen);
  93         down->cache_tree = NULL;
  94         down->namelen = pathlen;
  95
  96         if (pos < it->subtree_nr)
  97                 MOVE_ARRAY(it->down + pos + 1, it->down + pos,
  98                            it->subtree_nr - pos - 1);
  99         it->down[pos] = down;
 100         return down;
 101 }
 102
 103 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
 104 {
 105         int pathlen = strlen(path);
 106         return find_subtree(it, path, pathlen, 1);
 107 }
 108
 109 static int do_invalidate_path(struct cache_tree *it, const char *path)
 110 {
 111         /* a/b/c
 112          * ==> invalidate self
 113          * ==> find "a", have it invalidate "b/c"
 114          * a
 115          * ==> invalidate self
 116          * ==> if "a" exists as a subtree, remove it.
 117          */
 118         const char *slash;
 119         int namelen;
 120         struct cache_tree_sub *down;
 121
 122 #if DEBUG_CACHE_TREE
 123         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 124 #endif
 125
 126         if (!it)
 127                 return 0;
 128         slash = strchrnul(path, '/');
 129         namelen = slash - path;
 130         it->entry_count = -1;
 131         if (!*slash) {
 132                 int pos;
 133                 pos = cache_tree_subtree_pos(it, path, namelen);
 134                 if (0 <= pos) {
 135                         cache_tree_free(&it->down[pos]->cache_tree);
 136                         free(it->down[pos]);
 137                         /* 0 1 2 3 4 5
 138                          *       ^     ^subtree_nr = 6
 139                          *       pos
 140                          * move 4 and 5 up one place (2 entries)
 141                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 142                          */
 143                         MOVE_ARRAY(it->down + pos, it->down + pos + 1,
 144                                    it->subtree_nr - pos - 1);
 145                         it->subtree_nr--;
 146                 }
 147                 return 1;
 148         }
 149         down = find_subtree(it, path, namelen, 0);
 150         if (down)
 151                 do_invalidate_path(down->cache_tree, slash + 1);
 152         return 1;
 153 }
 154
 155 void cache_tree_invalidate_path(struct index_state *istate, const char *path)
 156 {
 157         if (do_invalidate_path(istate->cache_tree, path))
 158                 istate->cache_changed |= CACHE_TREE_CHANGED;
 159 }
 160
 161 static int verify_cache(struct index_state *istate, int flags)
 162 {
 163         unsigned i, funny;
 164         int silent = flags & WRITE_TREE_SILENT;
 165
 166         /* Verify that the tree is merged */
 167         funny = 0;
 168         for (i = 0; i < istate->cache_nr; i++) {
 169                 const struct cache_entry *ce = istate->cache[i];
 170                 if (ce_stage(ce)) {
 171                         if (silent)
 172                                 return -1;
 173                         if (10 < ++funny) {
 174                                 fprintf(stderr, "...\n");
 175                                 break;
 176                         }
 177                         fprintf(stderr, "%s: unmerged (%s)\n",
 178                                 ce->name, oid_to_hex(&ce->oid));
 179                 }
 180         }
 181         if (funny)
 182                 return -1;
 183
 184         /* Also verify that the cache does not have path and path/file
 185          * at the same time.  At this point we know the cache has only
 186          * stage 0 entries.
 187          */
 188         funny = 0;
 189         for (i = 0; i + 1 < istate->cache_nr; i++) {
 190                 /* path/file always comes after path because of the way
 191                  * the cache is sorted.  Also path can appear only once,
 192                  * which means conflicting one would immediately follow.
 193                  */
 194                 const struct cache_entry *this_ce = istate->cache[i];
 195                 const struct cache_entry *next_ce = istate->cache[i + 1];
 196                 const char *this_name = this_ce->name;
 197                 const char *next_name = next_ce->name;
 198                 int this_len = ce_namelen(this_ce);
 199                 if (this_len < ce_namelen(next_ce) &&
 200                     next_name[this_len] == '/' &&
 201                     strncmp(this_name, next_name, this_len) == 0) {
 202                         if (10 < ++funny) {
 203                                 fprintf(stderr, "...\n");
 204                                 break;
 205                         }
 206                         fprintf(stderr, "You have both %s and %s\n",
 207                                 this_name, next_name);
 208                 }
 209         }
 210         if (funny)
 211                 return -1;
 212         return 0;
 213 }
 214
 215 static void discard_unused_subtrees(struct cache_tree *it)
 216 {
 217         struct cache_tree_sub **down = it->down;
 218         int nr = it->subtree_nr;
 219         int dst, src;
 220         for (dst = src = 0; src < nr; src++) {
 221                 struct cache_tree_sub *s = down[src];
 222                 if (s->used)
 223                         down[dst++] = s;
 224                 else {
 225                         cache_tree_free(&s->cache_tree);
 226                         free(s);
 227                         it->subtree_nr--;
 228                 }
 229         }
 230 }
 231
 232 int cache_tree_fully_valid(struct cache_tree *it)
 233 {
 234         int i;
 235         if (!it)
 236                 return 0;
 237         if (it->entry_count < 0 || !repo_has_object_file(the_repository, &it->oid))
 238                 return 0;
 239         for (i = 0; i < it->subtree_nr; i++) {
 240                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 241                         return 0;
 242         }
 243         return 1;
 244 }
 245
 246 static int must_check_existence(const struct cache_entry *ce)
 247 {
 248         return !(repo_has_promisor_remote(the_repository) && ce_skip_worktree(ce));
 249 }
 250
 251 static int update_one(struct cache_tree *it,
 252                       struct cache_entry **cache,
 253                       int entries,
 254                       const char *base,
 255                       int baselen,
 256                       int *skip_count,
 257                       int flags)
 258 {
 259         struct strbuf buffer;
 260         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 261         int dryrun = flags & WRITE_TREE_DRY_RUN;
 262         int repair = flags & WRITE_TREE_REPAIR;
 263         int to_invalidate = 0;
 264         int i;
 265
 266         assert(!(dryrun && repair));
 267
 268         *skip_count = 0;
 269
 270         /*
 271          * If the first entry of this region is a sparse directory
 272          * entry corresponding exactly to 'base', then this cache_tree
 273          * struct is a "leaf" in the data structure, pointing to the
 274          * tree OID specified in the entry.
 275          */
 276         if (entries > 0) {
 277                 const struct cache_entry *ce = cache[0];
 278
 279                 if (S_ISSPARSEDIR(ce->ce_mode) &&
 280                     ce->ce_namelen == baselen &&
 281                     !strncmp(ce->name, base, baselen)) {
 282                         it->entry_count = 1;
 283                         oidcpy(&it->oid, &ce->oid);
 284                         return 1;
 285                 }
 286         }
 287
 288         if (0 <= it->entry_count && repo_has_object_file(the_repository, &it->oid))
 289                 return it->entry_count;
 290
 291         /*
 292          * We first scan for subtrees and update them; we start by
 293          * marking existing subtrees -- the ones that are unmarked
 294          * should not be in the result.
 295          */
 296         for (i = 0; i < it->subtree_nr; i++)
 297                 it->down[i]->used = 0;
 298
 299         /*
 300          * Find the subtrees and update them.
 301          */
 302         i = 0;
 303         while (i < entries) {
 304                 const struct cache_entry *ce = cache[i];
 305                 struct cache_tree_sub *sub;
 306                 const char *path, *slash;
 307                 int pathlen, sublen, subcnt, subskip;
 308
 309                 path = ce->name;
 310                 pathlen = ce_namelen(ce);
 311                 if (pathlen <= baselen || memcmp(base, path, baselen))
 312                         break; /* at the end of this level */
 313
 314                 slash = strchr(path + baselen, '/');
 315                 if (!slash) {
 316                         i++;
 317                         continue;
 318                 }
 319                 /*
 320                  * a/bbb/c (base = a/, slash = /c)
 321                  * ==>
 322                  * path+baselen = bbb/c, sublen = 3
 323                  */
 324                 sublen = slash - (path + baselen);
 325                 sub = find_subtree(it, path + baselen, sublen, 1);
 326                 if (!sub->cache_tree)
 327                         sub->cache_tree = cache_tree();
 328                 subcnt = update_one(sub->cache_tree,
 329                                     cache + i, entries - i,
 330                                     path,
 331                                     baselen + sublen + 1,
 332                                     &subskip,
 333                                     flags);
 334                 if (subcnt < 0)
 335                         return subcnt;
 336                 if (!subcnt)
 337                         die("index cache-tree records empty sub-tree");
 338                 i += subcnt;
 339                 sub->count = subcnt; /* to be used in the next loop */
 340                 *skip_count += subskip;
 341                 sub->used = 1;
 342         }
 343
 344         discard_unused_subtrees(it);
 345
 346         /*
 347          * Then write out the tree object for this level.
 348          */
 349         strbuf_init(&buffer, 8192);
 350
 351         i = 0;
 352         while (i < entries) {
 353                 const struct cache_entry *ce = cache[i];
 354                 struct cache_tree_sub *sub = NULL;
 355                 const char *path, *slash;
 356                 int pathlen, entlen;
 357                 const struct object_id *oid;
 358                 unsigned mode;
 359                 int expected_missing = 0;
 360                 int contains_ita = 0;
 361                 int ce_missing_ok;
 362
 363                 path = ce->name;
 364                 pathlen = ce_namelen(ce);
 365                 if (pathlen <= baselen || memcmp(base, path, baselen))
 366                         break; /* at the end of this level */
 367
 368                 slash = strchr(path + baselen, '/');
 369                 if (slash) {
 370                         entlen = slash - (path + baselen);
 371                         sub = find_subtree(it, path + baselen, entlen, 0);
 372                         if (!sub)
 373                                 die("cache-tree.c: '%.*s' in '%s' not found",
 374                                     entlen, path + baselen, path);
 375                         i += sub->count;
 376                         oid = &sub->cache_tree->oid;
 377                         mode = S_IFDIR;
 378                         contains_ita = sub->cache_tree->entry_count < 0;
 379                         if (contains_ita) {
 380                                 to_invalidate = 1;
 381                                 expected_missing = 1;
 382                         }
 383                 }
 384                 else {
 385                         oid = &ce->oid;
 386                         mode = ce->ce_mode;
 387                         entlen = pathlen - baselen;
 388                         i++;
 389                 }
 390
 391                 ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
 392                         !must_check_existence(ce);
 393                 if (is_null_oid(oid) ||
 394                     (!ce_missing_ok && !repo_has_object_file(the_repository, oid))) {
 395                         strbuf_release(&buffer);
 396                         if (expected_missing)
 397                                 return -1;
 398                         return error("invalid object %06o %s for '%.*s'",
 399                                 mode, oid_to_hex(oid), entlen+baselen, path);
 400                 }
 401
 402                 /*
 403                  * CE_REMOVE entries are removed before the index is
 404                  * written to disk. Skip them to remain consistent
 405                  * with the future on-disk index.
 406                  */
 407                 if (ce->ce_flags & CE_REMOVE) {
 408                         *skip_count = *skip_count + 1;
 409                         continue;
 410                 }
 411
 412                 /*
 413                  * CE_INTENT_TO_ADD entries exist in on-disk index but
 414                  * they are not part of generated trees. Invalidate up
 415                  * to root to force cache-tree users to read elsewhere.
 416                  */
 417                 if (!sub && ce_intent_to_add(ce)) {
 418                         to_invalidate = 1;
 419                         continue;
 420                 }
 421
 422                 /*
 423                  * "sub" can be an empty tree if all subentries are i-t-a.
 424                  */
 425                 if (contains_ita && is_empty_tree_oid(oid))
 426                         continue;
 427
 428                 strbuf_grow(&buffer, entlen + 100);
 429                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 430                 strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
 431
 432 #if DEBUG_CACHE_TREE
 433                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 434                         mode, entlen, path + baselen);
 435 #endif
 436         }
 437
 438         if (repair) {
 439                 struct object_id oid;
 440                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 441                                  OBJ_TREE, &oid);
 442                 if (repo_has_object_file_with_flags(the_repository, &oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 443                         oidcpy(&it->oid, &oid);
 444                 else
 445                         to_invalidate = 1;
 446         } else if (dryrun) {
 447                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 448                                  OBJ_TREE, &it->oid);
 449         } else if (write_object_file_flags(buffer.buf, buffer.len, OBJ_TREE,
 450                                            &it->oid, flags & WRITE_TREE_SILENT
 451                                            ? HASH_SILENT : 0)) {
 452                 strbuf_release(&buffer);
 453                 return -1;
 454         }
 455
 456         strbuf_release(&buffer);
 457         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 458 #if DEBUG_CACHE_TREE
 459         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 460                 it->entry_count, it->subtree_nr,
 461                 oid_to_hex(&it->oid));
 462 #endif
 463         return i;
 464 }
 465
 466 int cache_tree_update(struct index_state *istate, int flags)
 467 {
 468         int skip, i;
 469
 470         i = verify_cache(istate, flags);
 471
 472         if (i)
 473                 return i;
 474
 475         if (!istate->cache_tree)
 476                 istate->cache_tree = cache_tree();
 477
 478         if (!(flags & WRITE_TREE_MISSING_OK) && repo_has_promisor_remote(the_repository))
 479                 prefetch_cache_entries(istate, must_check_existence);
 480
 481         trace_performance_enter();
 482         trace2_region_enter("cache_tree", "update", the_repository);
 483         begin_odb_transaction();
 484         i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
 485                        "", 0, &skip, flags);
 486         end_odb_transaction();
 487         trace2_region_leave("cache_tree", "update", the_repository);
 488         trace_performance_leave("cache_tree_update");
 489         if (i < 0)
 490                 return i;
 491         istate->cache_changed |= CACHE_TREE_CHANGED;
 492         return 0;
 493 }
 494
 495 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 496                       const char *path, int pathlen)
 497 {
 498         int i;
 499
 500         /* One "cache-tree" entry consists of the following:
 501          * path (NUL terminated)
 502          * entry_count, subtree_nr ("%d %d\n")
 503          * tree-sha1 (missing if invalid)
 504          * subtree_nr "cache-tree" entries for subtrees.
 505          */
 506         strbuf_grow(buffer, pathlen + 100);
 507         strbuf_add(buffer, path, pathlen);
 508         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 509
 510 #if DEBUG_CACHE_TREE
 511         if (0 <= it->entry_count)
 512                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 513                         pathlen, path, it->entry_count, it->subtree_nr,
 514                         oid_to_hex(&it->oid));
 515         else
 516                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 517                         pathlen, path, it->subtree_nr);
 518 #endif
 519
 520         if (0 <= it->entry_count) {
 521                 strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
 522         }
 523         for (i = 0; i < it->subtree_nr; i++) {
 524                 struct cache_tree_sub *down = it->down[i];
 525                 if (i) {
 526                         struct cache_tree_sub *prev = it->down[i-1];
 527                         if (subtree_name_cmp(down->name, down->namelen,
 528                                              prev->name, prev->namelen) <= 0)
 529                                 die("fatal - unsorted cache subtree");
 530                 }
 531                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 532         }
 533 }
 534
 535 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 536 {
 537         trace2_region_enter("cache_tree", "write", the_repository);
 538         write_one(sb, root, "", 0);
 539         trace2_region_leave("cache_tree", "write", the_repository);
 540 }
 541
 542 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 543 {
 544         const char *buf = *buffer;
 545         unsigned long size = *size_p;
 546         const char *cp;
 547         char *ep;
 548         struct cache_tree *it;
 549         int i, subtree_nr;
 550         const unsigned rawsz = the_hash_algo->rawsz;
 551
 552         it = NULL;
 553         /* skip name, but make sure name exists */
 554         while (size && *buf) {
 555                 size--;
 556                 buf++;
 557         }
 558         if (!size)
 559                 goto free_return;
 560         buf++; size--;
 561         it = cache_tree();
 562
 563         cp = buf;
 564         it->entry_count = strtol(cp, &ep, 10);
 565         if (cp == ep)
 566                 goto free_return;
 567         cp = ep;
 568         subtree_nr = strtol(cp, &ep, 10);
 569         if (cp == ep)
 570                 goto free_return;
 571         while (size && *buf && *buf != '\n') {
 572                 size--;
 573                 buf++;
 574         }
 575         if (!size)
 576                 goto free_return;
 577         buf++; size--;
 578         if (0 <= it->entry_count) {
 579                 if (size < rawsz)
 580                         goto free_return;
 581                 oidread(&it->oid, (const unsigned char *)buf);
 582                 buf += rawsz;
 583                 size -= rawsz;
 584         }
 585
 586 #if DEBUG_CACHE_TREE
 587         if (0 <= it->entry_count)
 588                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 589                         *buffer, it->entry_count, subtree_nr,
 590                         oid_to_hex(&it->oid));
 591         else
 592                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 593                         *buffer, subtree_nr);
 594 #endif
 595
 596         /*
 597          * Just a heuristic -- we do not add directories that often but
 598          * we do not want to have to extend it immediately when we do,
 599          * hence +2.
 600          */
 601         it->subtree_alloc = subtree_nr + 2;
 602         CALLOC_ARRAY(it->down, it->subtree_alloc);
 603         for (i = 0; i < subtree_nr; i++) {
 604                 /* read each subtree */
 605                 struct cache_tree *sub;
 606                 struct cache_tree_sub *subtree;
 607                 const char *name = buf;
 608
 609                 sub = read_one(&buf, &size);
 610                 if (!sub)
 611                         goto free_return;
 612                 subtree = cache_tree_sub(it, name);
 613                 subtree->cache_tree = sub;
 614         }
 615         if (subtree_nr != it->subtree_nr)
 616                 die("cache-tree: internal error");
 617         *buffer = buf;
 618         *size_p = size;
 619         return it;
 620
 621  free_return:
 622         cache_tree_free(&it);
 623         return NULL;
 624 }
 625
 626 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 627 {
 628         struct cache_tree *result;
 629
 630         if (buffer[0])
 631                 return NULL; /* not the whole tree */
 632
 633         trace2_region_enter("cache_tree", "read", the_repository);
 634         result = read_one(&buffer, &size);
 635         trace2_region_leave("cache_tree", "read", the_repository);
 636
 637         return result;
 638 }
 639
 640 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 641 {
 642         if (!it)
 643                 return NULL;
 644         while (*path) {
 645                 const char *slash;
 646                 struct cache_tree_sub *sub;
 647
 648                 slash = strchrnul(path, '/');
 649                 /*
 650                  * Between path and slash is the name of the subtree
 651                  * to look for.
 652                  */
 653                 sub = find_subtree(it, path, slash - path, 0);
 654                 if (!sub)
 655                         return NULL;
 656                 it = sub->cache_tree;
 657
 658                 path = slash;
 659                 while (*path == '/')
 660                         path++;
 661         }
 662         return it;
 663 }
 664
 665 static int write_index_as_tree_internal(struct object_id *oid,
 666                                         struct index_state *index_state,
 667                                         int cache_tree_valid,
 668                                         int flags,
 669                                         const char *prefix)
 670 {
 671         if (flags & WRITE_TREE_IGNORE_CACHE_TREE) {
 672                 cache_tree_free(&index_state->cache_tree);
 673                 cache_tree_valid = 0;
 674         }
 675
 676         if (!cache_tree_valid && cache_tree_update(index_state, flags) < 0)
 677                 return WRITE_TREE_UNMERGED_INDEX;
 678
 679         if (prefix) {
 680                 struct cache_tree *subtree;
 681                 subtree = cache_tree_find(index_state->cache_tree, prefix);
 682                 if (!subtree)
 683                         return WRITE_TREE_PREFIX_ERROR;
 684                 oidcpy(oid, &subtree->oid);
 685         }
 686         else
 687                 oidcpy(oid, &index_state->cache_tree->oid);
 688
 689         return 0;
 690 }
 691
 692 struct tree* write_in_core_index_as_tree(struct repository *repo) {
 693         struct object_id o;
 694         int was_valid, ret;
 695
 696         struct index_state *index_state = repo->index;
 697         was_valid = index_state->cache_tree &&
 698                     cache_tree_fully_valid(index_state->cache_tree);
 699
 700         ret = write_index_as_tree_internal(&o, index_state, was_valid, 0, NULL);
 701         if (ret == WRITE_TREE_UNMERGED_INDEX) {
 702                 int i;
 703                 bug("there are unmerged index entries:");
 704                 for (i = 0; i < index_state->cache_nr; i++) {
 705                         const struct cache_entry *ce = index_state->cache[i];
 706                         if (ce_stage(ce))
 707                                 bug("%d %.*s", ce_stage(ce),
 708                                     (int)ce_namelen(ce), ce->name);
 709                 }
 710                 BUG("unmerged index entries when writing in-core index");
 711         }
 712
 713         return lookup_tree(repo, &index_state->cache_tree->oid);
 714 }
 715
 716
 717 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 718 {
 719         int entries, was_valid;
 720         struct lock_file lock_file = LOCK_INIT;
 721         int ret;
 722
 723         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 724
 725         entries = read_index_from(index_state, index_path, get_git_dir());
 726         if (entries < 0) {
 727                 ret = WRITE_TREE_UNREADABLE_INDEX;
 728                 goto out;
 729         }
 730
 731         was_valid = !(flags & WRITE_TREE_IGNORE_CACHE_TREE) &&
 732                     index_state->cache_tree &&
 733                     cache_tree_fully_valid(index_state->cache_tree);
 734
 735         ret = write_index_as_tree_internal(oid, index_state, was_valid, flags,
 736                                            prefix);
 737         if (!ret && !was_valid) {
 738                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
 739                 /* Not being able to write is fine -- we are only interested
 740                  * in updating the cache-tree part, and if the next caller
 741                  * ends up using the old index with unupdated cache-tree part
 742                  * it misses the work we did here, but that is just a
 743                  * performance penalty and not a big deal.
 744                  */
 745         }
 746
 747 out:
 748         rollback_lock_file(&lock_file);
 749         return ret;
 750 }
 751
 752 static void prime_cache_tree_sparse_dir(struct cache_tree *it,
 753                                         struct tree *tree)
 754 {
 755
 756         oidcpy(&it->oid, &tree->object.oid);
 757         it->entry_count = 1;
 758 }
 759
 760 static void prime_cache_tree_rec(struct repository *r,
 761                                  struct cache_tree *it,
 762                                  struct tree *tree,
 763                                  struct strbuf *tree_path)
 764 {
 765         struct tree_desc desc;
 766         struct name_entry entry;
 767         int cnt;
 768         size_t base_path_len = tree_path->len;
 769
 770         oidcpy(&it->oid, &tree->object.oid);
 771
 772         init_tree_desc(&desc, tree->buffer, tree->size);
 773         cnt = 0;
 774         while (tree_entry(&desc, &entry)) {
 775                 if (!S_ISDIR(entry.mode))
 776                         cnt++;
 777                 else {
 778                         struct cache_tree_sub *sub;
 779                         struct tree *subtree = lookup_tree(r, &entry.oid);
 780
 781                         if (parse_tree(subtree) < 0)
 782                                 exit(128);
 783                         sub = cache_tree_sub(it, entry.path);
 784                         sub->cache_tree = cache_tree();
 785
 786                         /*
 787                          * Recursively-constructed subtree path is only needed when working
 788                          * in a sparse index (where it's used to determine whether the
 789                          * subtree is a sparse directory in the index).
 790                          */
 791                         if (r->index->sparse_index) {
 792                                 strbuf_setlen(tree_path, base_path_len);
 793                                 strbuf_add(tree_path, entry.path, entry.pathlen);
 794                                 strbuf_addch(tree_path, '/');
 795                         }
 796
 797                         /*
 798                          * If a sparse index is in use, the directory being processed may be
 799                          * sparse. To confirm that, we can check whether an entry with that
 800                          * exact name exists in the index. If it does, the created subtree
 801                          * should be sparse. Otherwise, cache tree expansion should continue
 802                          * as normal.
 803                          */
 804                         if (r->index->sparse_index &&
 805                             index_entry_exists(r->index, tree_path->buf, tree_path->len))
 806                                 prime_cache_tree_sparse_dir(sub->cache_tree, subtree);
 807                         else
 808                                 prime_cache_tree_rec(r, sub->cache_tree, subtree, tree_path);
 809                         cnt += sub->cache_tree->entry_count;
 810                 }
 811         }
 812
 813         it->entry_count = cnt;
 814 }
 815
 816 void prime_cache_tree(struct repository *r,
 817                       struct index_state *istate,
 818                       struct tree *tree)
 819 {
 820         struct strbuf tree_path = STRBUF_INIT;
 821
 822         trace2_region_enter("cache-tree", "prime_cache_tree", r);
 823         cache_tree_free(&istate->cache_tree);
 824         istate->cache_tree = cache_tree();
 825
 826         prime_cache_tree_rec(r, istate->cache_tree, tree, &tree_path);
 827         strbuf_release(&tree_path);
 828         istate->cache_changed |= CACHE_TREE_CHANGED;
 829         trace2_region_leave("cache-tree", "prime_cache_tree", r);
 830 }
 831
 832 /*
 833  * find the cache_tree that corresponds to the current level without
 834  * exploding the full path into textual form.  The root of the
 835  * cache tree is given as "root", and our current level is "info".
 836  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 837  * (2) Otherwise, find the cache_tree that corresponds to one level
 838  *     above us, and find ourselves in there.
 839  */
 840 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 841                                                          struct traverse_info *info)
 842 {
 843         struct cache_tree *our_parent;
 844
 845         if (!info->prev)
 846                 return root;
 847         our_parent = find_cache_tree_from_traversal(root, info->prev);
 848         return cache_tree_find(our_parent, info->name);
 849 }
 850
 851 int cache_tree_matches_traversal(struct cache_tree *root,
 852                                  struct name_entry *ent,
 853                                  struct traverse_info *info)
 854 {
 855         struct cache_tree *it;
 856
 857         it = find_cache_tree_from_traversal(root, info);
 858         it = cache_tree_find(it, ent->path);
 859         if (it && it->entry_count > 0 && oideq(&ent->oid, &it->oid))
 860                 return it->entry_count;
 861         return 0;
 862 }
 863
 864 static void verify_one_sparse(struct index_state *istate,
 865                               struct strbuf *path,
 866                               int pos)
 867 {
 868         struct cache_entry *ce = istate->cache[pos];
 869
 870         if (!S_ISSPARSEDIR(ce->ce_mode))
 871                 BUG("directory '%s' is present in index, but not sparse",
 872                     path->buf);
 873 }
 874
 875 /*
 876  * Returns:
 877  *  0 - Verification completed.
 878  *  1 - Restart verification - a call to ensure_full_index() freed the cache
 879  *      tree that is being verified and verification needs to be restarted from
 880  *      the new toplevel cache tree.
 881  */
 882 static int verify_one(struct repository *r,
 883                       struct index_state *istate,
 884                       struct cache_tree *it,
 885                       struct strbuf *path)
 886 {
 887         int i, pos, len = path->len;
 888         struct strbuf tree_buf = STRBUF_INIT;
 889         struct object_id new_oid;
 890
 891         for (i = 0; i < it->subtree_nr; i++) {
 892                 strbuf_addf(path, "%s/", it->down[i]->name);
 893                 if (verify_one(r, istate, it->down[i]->cache_tree, path))
 894                         return 1;
 895                 strbuf_setlen(path, len);
 896         }
 897
 898         if (it->entry_count < 0 ||
 899             /* no verification on tests (t7003) that replace trees */
 900             lookup_replace_object(r, &it->oid) != &it->oid)
 901                 return 0;
 902
 903         if (path->len) {
 904                 /*
 905                  * If the index is sparse and the cache tree is not
 906                  * index_name_pos() may trigger ensure_full_index() which will
 907                  * free the tree that is being verified.
 908                  */
 909                 int is_sparse = istate->sparse_index;
 910                 pos = index_name_pos(istate, path->buf, path->len);
 911                 if (is_sparse && !istate->sparse_index)
 912                         return 1;
 913
 914                 if (pos >= 0) {
 915                         verify_one_sparse(istate, path, pos);
 916                         return 0;
 917                 }
 918
 919                 pos = -pos - 1;
 920         } else {
 921                 pos = 0;
 922         }
 923
 924         i = 0;
 925         while (i < it->entry_count) {
 926                 struct cache_entry *ce = istate->cache[pos + i];
 927                 const char *slash;
 928                 struct cache_tree_sub *sub = NULL;
 929                 const struct object_id *oid;
 930                 const char *name;
 931                 unsigned mode;
 932                 int entlen;
 933
 934                 if (ce->ce_flags & (CE_STAGEMASK | CE_INTENT_TO_ADD | CE_REMOVE))
 935                         BUG("%s with flags 0x%x should not be in cache-tree",
 936                             ce->name, ce->ce_flags);
 937                 name = ce->name + path->len;
 938                 slash = strchr(name, '/');
 939                 if (slash) {
 940                         entlen = slash - name;
 941                         sub = find_subtree(it, ce->name + path->len, entlen, 0);
 942                         if (!sub || sub->cache_tree->entry_count < 0)
 943                                 BUG("bad subtree '%.*s'", entlen, name);
 944                         oid = &sub->cache_tree->oid;
 945                         mode = S_IFDIR;
 946                         i += sub->cache_tree->entry_count;
 947                 } else {
 948                         oid = &ce->oid;
 949                         mode = ce->ce_mode;
 950                         entlen = ce_namelen(ce) - path->len;
 951                         i++;
 952                 }
 953                 strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
 954                 strbuf_add(&tree_buf, oid->hash, r->hash_algo->rawsz);
 955         }
 956         hash_object_file(r->hash_algo, tree_buf.buf, tree_buf.len, OBJ_TREE,
 957                          &new_oid);
 958         if (!oideq(&new_oid, &it->oid))
 959                 BUG("cache-tree for path %.*s does not match. "
 960                     "Expected %s got %s", len, path->buf,
 961                     oid_to_hex(&new_oid), oid_to_hex(&it->oid));
 962         strbuf_setlen(path, len);
 963         strbuf_release(&tree_buf);
 964         return 0;
 965 }
 966
 967 void cache_tree_verify(struct repository *r, struct index_state *istate)
 968 {
 969         struct strbuf path = STRBUF_INIT;
 970
 971         if (!istate->cache_tree)
 972                 return;
 973         if (verify_one(r, istate, istate->cache_tree, &path)) {
 974                 strbuf_reset(&path);
 975                 if (verify_one(r, istate, istate->cache_tree, &path))
 976                         BUG("ensure_full_index() called twice while verifying cache tree");
 977         }
 978         strbuf_release(&path);
 979 }