cache-tree.c

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