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-file.h"
  11 #include "object-store.h"
  12 #include "replace-object.h"
  13 #include "promisor-remote.h"
  14 #include "sparse-index.h"
  15 #include "trace.h"
  16 #include "trace2.h"
  17
  18 #ifndef DEBUG_CACHE_TREE
  19 #define DEBUG_CACHE_TREE 0
  20 #endif
  21
  22 struct cache_tree *cache_tree(void)
  23 {
  24         struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
  25         it->entry_count = -1;
  26         return it;
  27 }
  28
  29 void cache_tree_free(struct cache_tree **it_p)
  30 {
  31         int i;
  32         struct cache_tree *it = *it_p;
  33
  34         if (!it)
  35                 return;
  36         for (i = 0; i < it->subtree_nr; i++)
  37                 if (it->down[i]) {
  38                         cache_tree_free(&it->down[i]->cache_tree);
  39                         free(it->down[i]);
  40                 }
  41         free(it->down);
  42         free(it);
  43         *it_p = NULL;
  44 }
  45
  46 static int subtree_name_cmp(const char *one, int onelen,
  47                             const char *two, int twolen)
  48 {
  49         if (onelen < twolen)
  50                 return -1;
  51         if (twolen < onelen)
  52                 return 1;
  53         return memcmp(one, two, onelen);
  54 }
  55
  56 int cache_tree_subtree_pos(struct cache_tree *it, const char *path, int pathlen)
  57 {
  58         struct cache_tree_sub **down = it->down;
  59         int lo, hi;
  60         lo = 0;
  61         hi = it->subtree_nr;
  62         while (lo < hi) {
  63                 int mi = lo + (hi - lo) / 2;
  64                 struct cache_tree_sub *mdl = down[mi];
  65                 int cmp = subtree_name_cmp(path, pathlen,
  66                                            mdl->name, mdl->namelen);
  67                 if (!cmp)
  68                         return mi;
  69                 if (cmp < 0)
  70                         hi = mi;
  71                 else
  72                         lo = mi + 1;
  73         }
  74         return -lo-1;
  75 }
  76
  77 static struct cache_tree_sub *find_subtree(struct cache_tree *it,
  78                                            const char *path,
  79                                            int pathlen,
  80                                            int create)
  81 {
  82         struct cache_tree_sub *down;
  83         int pos = cache_tree_subtree_pos(it, path, pathlen);
  84         if (0 <= pos)
  85                 return it->down[pos];
  86         if (!create)
  87                 return NULL;
  88
  89         pos = -pos-1;
  90         ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
  91         it->subtree_nr++;
  92
  93         FLEX_ALLOC_MEM(down, name, path, pathlen);
  94         down->cache_tree = NULL;
  95         down->namelen = pathlen;
  96
  97         if (pos < it->subtree_nr)
  98                 MOVE_ARRAY(it->down + pos + 1, it->down + pos,
  99                            it->subtree_nr - pos - 1);
 100         it->down[pos] = down;
 101         return down;
 102 }
 103
 104 struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
 105 {
 106         int pathlen = strlen(path);
 107         return find_subtree(it, path, pathlen, 1);
 108 }
 109
 110 static int do_invalidate_path(struct cache_tree *it, const char *path)
 111 {
 112         /* a/b/c
 113          * ==> invalidate self
 114          * ==> find "a", have it invalidate "b/c"
 115          * a
 116          * ==> invalidate self
 117          * ==> if "a" exists as a subtree, remove it.
 118          */
 119         const char *slash;
 120         int namelen;
 121         struct cache_tree_sub *down;
 122
 123 #if DEBUG_CACHE_TREE
 124         fprintf(stderr, "cache-tree invalidate <%s>\n", path);
 125 #endif
 126
 127         if (!it)
 128                 return 0;
 129         slash = strchrnul(path, '/');
 130         namelen = slash - path;
 131         it->entry_count = -1;
 132         if (!*slash) {
 133                 int pos;
 134                 pos = cache_tree_subtree_pos(it, path, namelen);
 135                 if (0 <= pos) {
 136                         cache_tree_free(&it->down[pos]->cache_tree);
 137                         free(it->down[pos]);
 138                         /* 0 1 2 3 4 5
 139                          *       ^     ^subtree_nr = 6
 140                          *       pos
 141                          * move 4 and 5 up one place (2 entries)
 142                          * 2 = 6 - 3 - 1 = subtree_nr - pos - 1
 143                          */
 144                         MOVE_ARRAY(it->down + pos, it->down + pos + 1,
 145                                    it->subtree_nr - pos - 1);
 146                         it->subtree_nr--;
 147                 }
 148                 return 1;
 149         }
 150         down = find_subtree(it, path, namelen, 0);
 151         if (down)
 152                 do_invalidate_path(down->cache_tree, slash + 1);
 153         return 1;
 154 }
 155
 156 void cache_tree_invalidate_path(struct index_state *istate, const char *path)
 157 {
 158         if (do_invalidate_path(istate->cache_tree, path))
 159                 istate->cache_changed |= CACHE_TREE_CHANGED;
 160 }
 161
 162 static int verify_cache(struct index_state *istate, int flags)
 163 {
 164         unsigned i, funny;
 165         int silent = flags & WRITE_TREE_SILENT;
 166
 167         /* Verify that the tree is merged */
 168         funny = 0;
 169         for (i = 0; i < istate->cache_nr; i++) {
 170                 const struct cache_entry *ce = istate->cache[i];
 171                 if (ce_stage(ce)) {
 172                         if (silent)
 173                                 return -1;
 174                         if (10 < ++funny) {
 175                                 fprintf(stderr, "...\n");
 176                                 break;
 177                         }
 178                         fprintf(stderr, "%s: unmerged (%s)\n",
 179                                 ce->name, oid_to_hex(&ce->oid));
 180                 }
 181         }
 182         if (funny)
 183                 return -1;
 184
 185         /* Also verify that the cache does not have path and path/file
 186          * at the same time.  At this point we know the cache has only
 187          * stage 0 entries.
 188          */
 189         funny = 0;
 190         for (i = 0; i + 1 < istate->cache_nr; i++) {
 191                 /* path/file always comes after path because of the way
 192                  * the cache is sorted.  Also path can appear only once,
 193                  * which means conflicting one would immediately follow.
 194                  */
 195                 const struct cache_entry *this_ce = istate->cache[i];
 196                 const struct cache_entry *next_ce = istate->cache[i + 1];
 197                 const char *this_name = this_ce->name;
 198                 const char *next_name = next_ce->name;
 199                 int this_len = ce_namelen(this_ce);
 200                 if (this_len < ce_namelen(next_ce) &&
 201                     next_name[this_len] == '/' &&
 202                     strncmp(this_name, next_name, this_len) == 0) {
 203                         if (10 < ++funny) {
 204                                 fprintf(stderr, "...\n");
 205                                 break;
 206                         }
 207                         fprintf(stderr, "You have both %s and %s\n",
 208                                 this_name, next_name);
 209                 }
 210         }
 211         if (funny)
 212                 return -1;
 213         return 0;
 214 }
 215
 216 static void discard_unused_subtrees(struct cache_tree *it)
 217 {
 218         struct cache_tree_sub **down = it->down;
 219         int nr = it->subtree_nr;
 220         int dst, src;
 221         for (dst = src = 0; src < nr; src++) {
 222                 struct cache_tree_sub *s = down[src];
 223                 if (s->used)
 224                         down[dst++] = s;
 225                 else {
 226                         cache_tree_free(&s->cache_tree);
 227                         free(s);
 228                         it->subtree_nr--;
 229                 }
 230         }
 231 }
 232
 233 int cache_tree_fully_valid(struct cache_tree *it)
 234 {
 235         int i;
 236         if (!it)
 237                 return 0;
 238         if (it->entry_count < 0 || !repo_has_object_file(the_repository, &it->oid))
 239                 return 0;
 240         for (i = 0; i < it->subtree_nr; i++) {
 241                 if (!cache_tree_fully_valid(it->down[i]->cache_tree))
 242                         return 0;
 243         }
 244         return 1;
 245 }
 246
 247 static int must_check_existence(const struct cache_entry *ce)
 248 {
 249         return !(repo_has_promisor_remote(the_repository) && ce_skip_worktree(ce));
 250 }
 251
 252 static int update_one(struct cache_tree *it,
 253                       struct cache_entry **cache,
 254                       int entries,
 255                       const char *base,
 256                       int baselen,
 257                       int *skip_count,
 258                       int flags)
 259 {
 260         struct strbuf buffer;
 261         int missing_ok = flags & WRITE_TREE_MISSING_OK;
 262         int dryrun = flags & WRITE_TREE_DRY_RUN;
 263         int repair = flags & WRITE_TREE_REPAIR;
 264         int to_invalidate = 0;
 265         int i;
 266
 267         assert(!(dryrun && repair));
 268
 269         *skip_count = 0;
 270
 271         /*
 272          * If the first entry of this region is a sparse directory
 273          * entry corresponding exactly to 'base', then this cache_tree
 274          * struct is a "leaf" in the data structure, pointing to the
 275          * tree OID specified in the entry.
 276          */
 277         if (entries > 0) {
 278                 const struct cache_entry *ce = cache[0];
 279
 280                 if (S_ISSPARSEDIR(ce->ce_mode) &&
 281                     ce->ce_namelen == baselen &&
 282                     !strncmp(ce->name, base, baselen)) {
 283                         it->entry_count = 1;
 284                         oidcpy(&it->oid, &ce->oid);
 285                         return 1;
 286                 }
 287         }
 288
 289         if (0 <= it->entry_count && repo_has_object_file(the_repository, &it->oid))
 290                 return it->entry_count;
 291
 292         /*
 293          * We first scan for subtrees and update them; we start by
 294          * marking existing subtrees -- the ones that are unmarked
 295          * should not be in the result.
 296          */
 297         for (i = 0; i < it->subtree_nr; i++)
 298                 it->down[i]->used = 0;
 299
 300         /*
 301          * Find the subtrees and update them.
 302          */
 303         i = 0;
 304         while (i < entries) {
 305                 const struct cache_entry *ce = cache[i];
 306                 struct cache_tree_sub *sub;
 307                 const char *path, *slash;
 308                 int pathlen, sublen, subcnt, subskip;
 309
 310                 path = ce->name;
 311                 pathlen = ce_namelen(ce);
 312                 if (pathlen <= baselen || memcmp(base, path, baselen))
 313                         break; /* at the end of this level */
 314
 315                 slash = strchr(path + baselen, '/');
 316                 if (!slash) {
 317                         i++;
 318                         continue;
 319                 }
 320                 /*
 321                  * a/bbb/c (base = a/, slash = /c)
 322                  * ==>
 323                  * path+baselen = bbb/c, sublen = 3
 324                  */
 325                 sublen = slash - (path + baselen);
 326                 sub = find_subtree(it, path + baselen, sublen, 1);
 327                 if (!sub->cache_tree)
 328                         sub->cache_tree = cache_tree();
 329                 subcnt = update_one(sub->cache_tree,
 330                                     cache + i, entries - i,
 331                                     path,
 332                                     baselen + sublen + 1,
 333                                     &subskip,
 334                                     flags);
 335                 if (subcnt < 0)
 336                         return subcnt;
 337                 if (!subcnt)
 338                         die("index cache-tree records empty sub-tree");
 339                 i += subcnt;
 340                 sub->count = subcnt; /* to be used in the next loop */
 341                 *skip_count += subskip;
 342                 sub->used = 1;
 343         }
 344
 345         discard_unused_subtrees(it);
 346
 347         /*
 348          * Then write out the tree object for this level.
 349          */
 350         strbuf_init(&buffer, 8192);
 351
 352         i = 0;
 353         while (i < entries) {
 354                 const struct cache_entry *ce = cache[i];
 355                 struct cache_tree_sub *sub = NULL;
 356                 const char *path, *slash;
 357                 int pathlen, entlen;
 358                 const struct object_id *oid;
 359                 unsigned mode;
 360                 int expected_missing = 0;
 361                 int contains_ita = 0;
 362                 int ce_missing_ok;
 363
 364                 path = ce->name;
 365                 pathlen = ce_namelen(ce);
 366                 if (pathlen <= baselen || memcmp(base, path, baselen))
 367                         break; /* at the end of this level */
 368
 369                 slash = strchr(path + baselen, '/');
 370                 if (slash) {
 371                         entlen = slash - (path + baselen);
 372                         sub = find_subtree(it, path + baselen, entlen, 0);
 373                         if (!sub)
 374                                 die("cache-tree.c: '%.*s' in '%s' not found",
 375                                     entlen, path + baselen, path);
 376                         i += sub->count;
 377                         oid = &sub->cache_tree->oid;
 378                         mode = S_IFDIR;
 379                         contains_ita = sub->cache_tree->entry_count < 0;
 380                         if (contains_ita) {
 381                                 to_invalidate = 1;
 382                                 expected_missing = 1;
 383                         }
 384                 }
 385                 else {
 386                         oid = &ce->oid;
 387                         mode = ce->ce_mode;
 388                         entlen = pathlen - baselen;
 389                         i++;
 390                 }
 391
 392                 ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
 393                         !must_check_existence(ce);
 394                 if (is_null_oid(oid) ||
 395                     (!ce_missing_ok && !repo_has_object_file(the_repository, oid))) {
 396                         strbuf_release(&buffer);
 397                         if (expected_missing)
 398                                 return -1;
 399                         return error("invalid object %06o %s for '%.*s'",
 400                                 mode, oid_to_hex(oid), entlen+baselen, path);
 401                 }
 402
 403                 /*
 404                  * CE_REMOVE entries are removed before the index is
 405                  * written to disk. Skip them to remain consistent
 406                  * with the future on-disk index.
 407                  */
 408                 if (ce->ce_flags & CE_REMOVE) {
 409                         *skip_count = *skip_count + 1;
 410                         continue;
 411                 }
 412
 413                 /*
 414                  * CE_INTENT_TO_ADD entries exist in on-disk index but
 415                  * they are not part of generated trees. Invalidate up
 416                  * to root to force cache-tree users to read elsewhere.
 417                  */
 418                 if (!sub && ce_intent_to_add(ce)) {
 419                         to_invalidate = 1;
 420                         continue;
 421                 }
 422
 423                 /*
 424                  * "sub" can be an empty tree if all subentries are i-t-a.
 425                  */
 426                 if (contains_ita && is_empty_tree_oid(oid))
 427                         continue;
 428
 429                 strbuf_grow(&buffer, entlen + 100);
 430                 strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
 431                 strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
 432
 433 #if DEBUG_CACHE_TREE
 434                 fprintf(stderr, "cache-tree update-one %o %.*s\n",
 435                         mode, entlen, path + baselen);
 436 #endif
 437         }
 438
 439         if (repair) {
 440                 struct object_id oid;
 441                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 442                                  OBJ_TREE, &oid);
 443                 if (repo_has_object_file_with_flags(the_repository, &oid, OBJECT_INFO_SKIP_FETCH_OBJECT))
 444                         oidcpy(&it->oid, &oid);
 445                 else
 446                         to_invalidate = 1;
 447         } else if (dryrun) {
 448                 hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 449                                  OBJ_TREE, &it->oid);
 450         } else if (write_object_file_flags(buffer.buf, buffer.len, OBJ_TREE,
 451                                            &it->oid, flags & WRITE_TREE_SILENT
 452                                            ? HASH_SILENT : 0)) {
 453                 strbuf_release(&buffer);
 454                 return -1;
 455         }
 456
 457         strbuf_release(&buffer);
 458         it->entry_count = to_invalidate ? -1 : i - *skip_count;
 459 #if DEBUG_CACHE_TREE
 460         fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
 461                 it->entry_count, it->subtree_nr,
 462                 oid_to_hex(&it->oid));
 463 #endif
 464         return i;
 465 }
 466
 467 int cache_tree_update(struct index_state *istate, int flags)
 468 {
 469         int skip, i;
 470
 471         i = verify_cache(istate, flags);
 472
 473         if (i)
 474                 return i;
 475
 476         if (!istate->cache_tree)
 477                 istate->cache_tree = cache_tree();
 478
 479         if (!(flags & WRITE_TREE_MISSING_OK) && repo_has_promisor_remote(the_repository))
 480                 prefetch_cache_entries(istate, must_check_existence);
 481
 482         trace_performance_enter();
 483         trace2_region_enter("cache_tree", "update", the_repository);
 484         begin_odb_transaction();
 485         i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
 486                        "", 0, &skip, flags);
 487         end_odb_transaction();
 488         trace2_region_leave("cache_tree", "update", the_repository);
 489         trace_performance_leave("cache_tree_update");
 490         if (i < 0)
 491                 return i;
 492         istate->cache_changed |= CACHE_TREE_CHANGED;
 493         return 0;
 494 }
 495
 496 static void write_one(struct strbuf *buffer, struct cache_tree *it,
 497                       const char *path, int pathlen)
 498 {
 499         int i;
 500
 501         /* One "cache-tree" entry consists of the following:
 502          * path (NUL terminated)
 503          * entry_count, subtree_nr ("%d %d\n")
 504          * tree-sha1 (missing if invalid)
 505          * subtree_nr "cache-tree" entries for subtrees.
 506          */
 507         strbuf_grow(buffer, pathlen + 100);
 508         strbuf_add(buffer, path, pathlen);
 509         strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
 510
 511 #if DEBUG_CACHE_TREE
 512         if (0 <= it->entry_count)
 513                 fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
 514                         pathlen, path, it->entry_count, it->subtree_nr,
 515                         oid_to_hex(&it->oid));
 516         else
 517                 fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
 518                         pathlen, path, it->subtree_nr);
 519 #endif
 520
 521         if (0 <= it->entry_count) {
 522                 strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
 523         }
 524         for (i = 0; i < it->subtree_nr; i++) {
 525                 struct cache_tree_sub *down = it->down[i];
 526                 if (i) {
 527                         struct cache_tree_sub *prev = it->down[i-1];
 528                         if (subtree_name_cmp(down->name, down->namelen,
 529                                              prev->name, prev->namelen) <= 0)
 530                                 die("fatal - unsorted cache subtree");
 531                 }
 532                 write_one(buffer, down->cache_tree, down->name, down->namelen);
 533         }
 534 }
 535
 536 void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
 537 {
 538         trace2_region_enter("cache_tree", "write", the_repository);
 539         write_one(sb, root, "", 0);
 540         trace2_region_leave("cache_tree", "write", the_repository);
 541 }
 542
 543 static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 544 {
 545         const char *buf = *buffer;
 546         unsigned long size = *size_p;
 547         const char *cp;
 548         char *ep;
 549         struct cache_tree *it;
 550         int i, subtree_nr;
 551         const unsigned rawsz = the_hash_algo->rawsz;
 552
 553         it = NULL;
 554         /* skip name, but make sure name exists */
 555         while (size && *buf) {
 556                 size--;
 557                 buf++;
 558         }
 559         if (!size)
 560                 goto free_return;
 561         buf++; size--;
 562         it = cache_tree();
 563
 564         cp = buf;
 565         it->entry_count = strtol(cp, &ep, 10);
 566         if (cp == ep)
 567                 goto free_return;
 568         cp = ep;
 569         subtree_nr = strtol(cp, &ep, 10);
 570         if (cp == ep)
 571                 goto free_return;
 572         while (size && *buf && *buf != '\n') {
 573                 size--;
 574                 buf++;
 575         }
 576         if (!size)
 577                 goto free_return;
 578         buf++; size--;
 579         if (0 <= it->entry_count) {
 580                 if (size < rawsz)
 581                         goto free_return;
 582                 oidread(&it->oid, (const unsigned char *)buf);
 583                 buf += rawsz;
 584                 size -= rawsz;
 585         }
 586
 587 #if DEBUG_CACHE_TREE
 588         if (0 <= it->entry_count)
 589                 fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
 590                         *buffer, it->entry_count, subtree_nr,
 591                         oid_to_hex(&it->oid));
 592         else
 593                 fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
 594                         *buffer, subtree_nr);
 595 #endif
 596
 597         /*
 598          * Just a heuristic -- we do not add directories that often but
 599          * we do not want to have to extend it immediately when we do,
 600          * hence +2.
 601          */
 602         it->subtree_alloc = subtree_nr + 2;
 603         CALLOC_ARRAY(it->down, it->subtree_alloc);
 604         for (i = 0; i < subtree_nr; i++) {
 605                 /* read each subtree */
 606                 struct cache_tree *sub;
 607                 struct cache_tree_sub *subtree;
 608                 const char *name = buf;
 609
 610                 sub = read_one(&buf, &size);
 611                 if (!sub)
 612                         goto free_return;
 613                 subtree = cache_tree_sub(it, name);
 614                 subtree->cache_tree = sub;
 615         }
 616         if (subtree_nr != it->subtree_nr)
 617                 die("cache-tree: internal error");
 618         *buffer = buf;
 619         *size_p = size;
 620         return it;
 621
 622  free_return:
 623         cache_tree_free(&it);
 624         return NULL;
 625 }
 626
 627 struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
 628 {
 629         struct cache_tree *result;
 630
 631         if (buffer[0])
 632                 return NULL; /* not the whole tree */
 633
 634         trace2_region_enter("cache_tree", "read", the_repository);
 635         result = read_one(&buffer, &size);
 636         trace2_region_leave("cache_tree", "read", the_repository);
 637
 638         return result;
 639 }
 640
 641 static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
 642 {
 643         if (!it)
 644                 return NULL;
 645         while (*path) {
 646                 const char *slash;
 647                 struct cache_tree_sub *sub;
 648
 649                 slash = strchrnul(path, '/');
 650                 /*
 651                  * Between path and slash is the name of the subtree
 652                  * to look for.
 653                  */
 654                 sub = find_subtree(it, path, slash - path, 0);
 655                 if (!sub)
 656                         return NULL;
 657                 it = sub->cache_tree;
 658
 659                 path = slash;
 660                 while (*path == '/')
 661                         path++;
 662         }
 663         return it;
 664 }
 665
 666 static int write_index_as_tree_internal(struct object_id *oid,
 667                                         struct index_state *index_state,
 668                                         int cache_tree_valid,
 669                                         int flags,
 670                                         const char *prefix)
 671 {
 672         if (flags & WRITE_TREE_IGNORE_CACHE_TREE) {
 673                 cache_tree_free(&index_state->cache_tree);
 674                 cache_tree_valid = 0;
 675         }
 676
 677         if (!cache_tree_valid && cache_tree_update(index_state, flags) < 0)
 678                 return WRITE_TREE_UNMERGED_INDEX;
 679
 680         if (prefix) {
 681                 struct cache_tree *subtree;
 682                 subtree = cache_tree_find(index_state->cache_tree, prefix);
 683                 if (!subtree)
 684                         return WRITE_TREE_PREFIX_ERROR;
 685                 oidcpy(oid, &subtree->oid);
 686         }
 687         else
 688                 oidcpy(oid, &index_state->cache_tree->oid);
 689
 690         return 0;
 691 }
 692
 693 struct tree* write_in_core_index_as_tree(struct repository *repo) {
 694         struct object_id o;
 695         int was_valid, ret;
 696
 697         struct index_state *index_state = repo->index;
 698         was_valid = index_state->cache_tree &&
 699                     cache_tree_fully_valid(index_state->cache_tree);
 700
 701         ret = write_index_as_tree_internal(&o, index_state, was_valid, 0, NULL);
 702         if (ret == WRITE_TREE_UNMERGED_INDEX) {
 703                 int i;
 704                 bug("there are unmerged index entries:");
 705                 for (i = 0; i < index_state->cache_nr; i++) {
 706                         const struct cache_entry *ce = index_state->cache[i];
 707                         if (ce_stage(ce))
 708                                 bug("%d %.*s", ce_stage(ce),
 709                                     (int)ce_namelen(ce), ce->name);
 710                 }
 711                 BUG("unmerged index entries when writing in-core index");
 712         }
 713
 714         return lookup_tree(repo, &index_state->cache_tree->oid);
 715 }
 716
 717
 718 int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
 719 {
 720         int entries, was_valid;
 721         struct lock_file lock_file = LOCK_INIT;
 722         int ret;
 723
 724         hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
 725
 726         entries = read_index_from(index_state, index_path, get_git_dir());
 727         if (entries < 0) {
 728                 ret = WRITE_TREE_UNREADABLE_INDEX;
 729                 goto out;
 730         }
 731
 732         was_valid = !(flags & WRITE_TREE_IGNORE_CACHE_TREE) &&
 733                     index_state->cache_tree &&
 734                     cache_tree_fully_valid(index_state->cache_tree);
 735
 736         ret = write_index_as_tree_internal(oid, index_state, was_valid, flags,
 737                                            prefix);
 738         if (!ret && !was_valid) {
 739                 write_locked_index(index_state, &lock_file, COMMIT_LOCK);
 740                 /* Not being able to write is fine -- we are only interested
 741                  * in updating the cache-tree part, and if the next caller
 742                  * ends up using the old index with unupdated cache-tree part
 743                  * it misses the work we did here, but that is just a
 744                  * performance penalty and not a big deal.
 745                  */
 746         }
 747
 748 out:
 749         rollback_lock_file(&lock_file);
 750         return ret;
 751 }
 752
 753 static void prime_cache_tree_sparse_dir(struct cache_tree *it,
 754                                         struct tree *tree)
 755 {
 756
 757         oidcpy(&it->oid, &tree->object.oid);
 758         it->entry_count = 1;
 759 }
 760
 761 static void prime_cache_tree_rec(struct repository *r,
 762                                  struct cache_tree *it,
 763                                  struct tree *tree,
 764                                  struct strbuf *tree_path)
 765 {
 766         struct tree_desc desc;
 767         struct name_entry entry;
 768         int cnt;
 769         size_t base_path_len = tree_path->len;
 770
 771         oidcpy(&it->oid, &tree->object.oid);
 772
 773         init_tree_desc(&desc, tree->buffer, tree->size);
 774         cnt = 0;
 775         while (tree_entry(&desc, &entry)) {
 776                 if (!S_ISDIR(entry.mode))
 777                         cnt++;
 778                 else {
 779                         struct cache_tree_sub *sub;
 780                         struct tree *subtree = lookup_tree(r, &entry.oid);
 781
 782                         if (!subtree->object.parsed)
 783                                 parse_tree(subtree);
 784                         sub = cache_tree_sub(it, entry.path);
 785                         sub->cache_tree = cache_tree();
 786
 787                         /*
 788                          * Recursively-constructed subtree path is only needed when working
 789                          * in a sparse index (where it's used to determine whether the
 790                          * subtree is a sparse directory in the index).
 791                          */
 792                         if (r->index->sparse_index) {
 793                                 strbuf_setlen(tree_path, base_path_len);
 794                                 strbuf_add(tree_path, entry.path, entry.pathlen);
 795                                 strbuf_addch(tree_path, '/');
 796                         }
 797
 798                         /*
 799                          * If a sparse index is in use, the directory being processed may be
 800                          * sparse. To confirm that, we can check whether an entry with that
 801                          * exact name exists in the index. If it does, the created subtree
 802                          * should be sparse. Otherwise, cache tree expansion should continue
 803                          * as normal.
 804                          */
 805                         if (r->index->sparse_index &&
 806                             index_entry_exists(r->index, tree_path->buf, tree_path->len))
 807                                 prime_cache_tree_sparse_dir(sub->cache_tree, subtree);
 808                         else
 809                                 prime_cache_tree_rec(r, sub->cache_tree, subtree, tree_path);
 810                         cnt += sub->cache_tree->entry_count;
 811                 }
 812         }
 813
 814         it->entry_count = cnt;
 815 }
 816
 817 void prime_cache_tree(struct repository *r,
 818                       struct index_state *istate,
 819                       struct tree *tree)
 820 {
 821         struct strbuf tree_path = STRBUF_INIT;
 822
 823         trace2_region_enter("cache-tree", "prime_cache_tree", r);
 824         cache_tree_free(&istate->cache_tree);
 825         istate->cache_tree = cache_tree();
 826
 827         prime_cache_tree_rec(r, istate->cache_tree, tree, &tree_path);
 828         strbuf_release(&tree_path);
 829         istate->cache_changed |= CACHE_TREE_CHANGED;
 830         trace2_region_leave("cache-tree", "prime_cache_tree", r);
 831 }
 832
 833 /*
 834  * find the cache_tree that corresponds to the current level without
 835  * exploding the full path into textual form.  The root of the
 836  * cache tree is given as "root", and our current level is "info".
 837  * (1) When at root level, info->prev is NULL, so it is "root" itself.
 838  * (2) Otherwise, find the cache_tree that corresponds to one level
 839  *     above us, and find ourselves in there.
 840  */
 841 static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
 842                                                          struct traverse_info *info)
 843 {
 844         struct cache_tree *our_parent;
 845
 846         if (!info->prev)
 847                 return root;
 848         our_parent = find_cache_tree_from_traversal(root, info->prev);
 849         return cache_tree_find(our_parent, info->name);
 850 }
 851
 852 int cache_tree_matches_traversal(struct cache_tree *root,
 853                                  struct name_entry *ent,
 854                                  struct traverse_info *info)
 855 {
 856         struct cache_tree *it;
 857
 858         it = find_cache_tree_from_traversal(root, info);
 859         it = cache_tree_find(it, ent->path);
 860         if (it && it->entry_count > 0 && oideq(&ent->oid, &it->oid))
 861                 return it->entry_count;
 862         return 0;
 863 }
 864
 865 static void verify_one_sparse(struct index_state *istate,
 866                               struct strbuf *path,
 867                               int pos)
 868 {
 869         struct cache_entry *ce = istate->cache[pos];
 870
 871         if (!S_ISSPARSEDIR(ce->ce_mode))
 872                 BUG("directory '%s' is present in index, but not sparse",
 873                     path->buf);
 874 }
 875
 876 /*
 877  * Returns:
 878  *  0 - Verification completed.
 879  *  1 - Restart verification - a call to ensure_full_index() freed the cache
 880  *      tree that is being verified and verification needs to be restarted from
 881  *      the new toplevel cache tree.
 882  */
 883 static int verify_one(struct repository *r,
 884                       struct index_state *istate,
 885                       struct cache_tree *it,
 886                       struct strbuf *path)
 887 {
 888         int i, pos, len = path->len;
 889         struct strbuf tree_buf = STRBUF_INIT;
 890         struct object_id new_oid;
 891
 892         for (i = 0; i < it->subtree_nr; i++) {
 893                 strbuf_addf(path, "%s/", it->down[i]->name);
 894                 if (verify_one(r, istate, it->down[i]->cache_tree, path))
 895                         return 1;
 896                 strbuf_setlen(path, len);
 897         }
 898
 899         if (it->entry_count < 0 ||
 900             /* no verification on tests (t7003) that replace trees */
 901             lookup_replace_object(r, &it->oid) != &it->oid)
 902                 return 0;
 903
 904         if (path->len) {
 905                 /*
 906                  * If the index is sparse and the cache tree is not
 907                  * index_name_pos() may trigger ensure_full_index() which will
 908                  * free the tree that is being verified.
 909                  */
 910                 int is_sparse = istate->sparse_index;
 911                 pos = index_name_pos(istate, path->buf, path->len);
 912                 if (is_sparse && !istate->sparse_index)
 913                         return 1;
 914
 915                 if (pos >= 0) {
 916                         verify_one_sparse(istate, path, pos);
 917                         return 0;
 918                 }
 919
 920                 pos = -pos - 1;
 921         } else {
 922                 pos = 0;
 923         }
 924
 925         i = 0;
 926         while (i < it->entry_count) {
 927                 struct cache_entry *ce = istate->cache[pos + i];
 928                 const char *slash;
 929                 struct cache_tree_sub *sub = NULL;
 930                 const struct object_id *oid;
 931                 const char *name;
 932                 unsigned mode;
 933                 int entlen;
 934
 935                 if (ce->ce_flags & (CE_STAGEMASK | CE_INTENT_TO_ADD | CE_REMOVE))
 936                         BUG("%s with flags 0x%x should not be in cache-tree",
 937                             ce->name, ce->ce_flags);
 938                 name = ce->name + path->len;
 939                 slash = strchr(name, '/');
 940                 if (slash) {
 941                         entlen = slash - name;
 942                         sub = find_subtree(it, ce->name + path->len, entlen, 0);
 943                         if (!sub || sub->cache_tree->entry_count < 0)
 944                                 BUG("bad subtree '%.*s'", entlen, name);
 945                         oid = &sub->cache_tree->oid;
 946                         mode = S_IFDIR;
 947                         i += sub->cache_tree->entry_count;
 948                 } else {
 949                         oid = &ce->oid;
 950                         mode = ce->ce_mode;
 951                         entlen = ce_namelen(ce) - path->len;
 952                         i++;
 953                 }
 954                 strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
 955                 strbuf_add(&tree_buf, oid->hash, r->hash_algo->rawsz);
 956         }
 957         hash_object_file(r->hash_algo, tree_buf.buf, tree_buf.len, OBJ_TREE,
 958                          &new_oid);
 959         if (!oideq(&new_oid, &it->oid))
 960                 BUG("cache-tree for path %.*s does not match. "
 961                     "Expected %s got %s", len, path->buf,
 962                     oid_to_hex(&new_oid), oid_to_hex(&it->oid));
 963         strbuf_setlen(path, len);
 964         strbuf_release(&tree_buf);
 965         return 0;
 966 }
 967
 968 void cache_tree_verify(struct repository *r, struct index_state *istate)
 969 {
 970         struct strbuf path = STRBUF_INIT;
 971
 972         if (!istate->cache_tree)
 973                 return;
 974         if (verify_one(r, istate, istate->cache_tree, &path)) {
 975                 strbuf_reset(&path);
 976                 if (verify_one(r, istate, istate->cache_tree, &path))
 977                         BUG("ensure_full_index() called twice while verifying cache tree");
 978         }
 979         strbuf_release(&path);
 980 }