name-hash.c

   1 /*
   2  * name-hash.c
   3  *
   4  * Hashing names in the index state
   5  *
   6  * Copyright (C) 2008 Linus Torvalds
   7  */
   8 #include "cache.h"
   9 #include "thread-utils.h"
  10 #include "trace2.h"
  11 #include "sparse-index.h"
  12
  13 struct dir_entry {
  14         struct hashmap_entry ent;
  15         struct dir_entry *parent;
  16         int nr;
  17         unsigned int namelen;
  18         char name[FLEX_ARRAY];
  19 };
  20
  21 static int dir_entry_cmp(const void *unused_cmp_data,
  22                          const struct hashmap_entry *eptr,
  23                          const struct hashmap_entry *entry_or_key,
  24                          const void *keydata)
  25 {
  26         const struct dir_entry *e1, *e2;
  27         const char *name = keydata;
  28
  29         e1 = container_of(eptr, const struct dir_entry, ent);
  30         e2 = container_of(entry_or_key, const struct dir_entry, ent);
  31
  32         return e1->namelen != e2->namelen || strncasecmp(e1->name,
  33                         name ? name : e2->name, e1->namelen);
  34 }
  35
  36 static struct dir_entry *find_dir_entry__hash(struct index_state *istate,
  37                 const char *name, unsigned int namelen, unsigned int hash)
  38 {
  39         struct dir_entry key;
  40         hashmap_entry_init(&key.ent, hash);
  41         key.namelen = namelen;
  42         return hashmap_get_entry(&istate->dir_hash, &key, ent, name);
  43 }
  44
  45 static struct dir_entry *find_dir_entry(struct index_state *istate,
  46                 const char *name, unsigned int namelen)
  47 {
  48         return find_dir_entry__hash(istate, name, namelen, memihash(name, namelen));
  49 }
  50
  51 static struct dir_entry *hash_dir_entry(struct index_state *istate,
  52                 struct cache_entry *ce, int namelen)
  53 {
  54         /*
  55          * Throw each directory component in the hash for quick lookup
  56          * during a git status. Directory components are stored without their
  57          * closing slash.  Despite submodules being a directory, they never
  58          * reach this point, because they are stored
  59          * in index_state.name_hash (as ordinary cache_entries).
  60          */
  61         struct dir_entry *dir;
  62
  63         /* get length of parent directory */
  64         while (namelen > 0 && !is_dir_sep(ce->name[namelen - 1]))
  65                 namelen--;
  66         if (namelen <= 0)
  67                 return NULL;
  68         namelen--;
  69
  70         /* lookup existing entry for that directory */
  71         dir = find_dir_entry(istate, ce->name, namelen);
  72         if (!dir) {
  73                 /* not found, create it and add to hash table */
  74                 FLEX_ALLOC_MEM(dir, name, ce->name, namelen);
  75                 hashmap_entry_init(&dir->ent, memihash(ce->name, namelen));
  76                 dir->namelen = namelen;
  77                 hashmap_add(&istate->dir_hash, &dir->ent);
  78
  79                 /* recursively add missing parent directories */
  80                 dir->parent = hash_dir_entry(istate, ce, namelen);
  81         }
  82         return dir;
  83 }
  84
  85 static void add_dir_entry(struct index_state *istate, struct cache_entry *ce)
  86 {
  87         /* Add reference to the directory entry (and parents if 0). */
  88         struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
  89         while (dir && !(dir->nr++))
  90                 dir = dir->parent;
  91 }
  92
  93 static void remove_dir_entry(struct index_state *istate, struct cache_entry *ce)
  94 {
  95         /*
  96          * Release reference to the directory entry. If 0, remove and continue
  97          * with parent directory.
  98          */
  99         struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
 100         while (dir && !(--dir->nr)) {
 101                 struct dir_entry *parent = dir->parent;
 102                 hashmap_remove(&istate->dir_hash, &dir->ent, NULL);
 103                 free(dir);
 104                 dir = parent;
 105         }
 106 }
 107
 108 static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
 109 {
 110         if (ce->ce_flags & CE_HASHED)
 111                 return;
 112         ce->ce_flags |= CE_HASHED;
 113
 114         if (!S_ISSPARSEDIR(ce->ce_mode)) {
 115                 hashmap_entry_init(&ce->ent, memihash(ce->name, ce_namelen(ce)));
 116                 hashmap_add(&istate->name_hash, &ce->ent);
 117         }
 118
 119         if (ignore_case)
 120                 add_dir_entry(istate, ce);
 121 }
 122
 123 static int cache_entry_cmp(const void *unused_cmp_data,
 124                            const struct hashmap_entry *eptr,
 125                            const struct hashmap_entry *entry_or_key,
 126                            const void *remove)
 127 {
 128         const struct cache_entry *ce1, *ce2;
 129
 130         ce1 = container_of(eptr, const struct cache_entry, ent);
 131         ce2 = container_of(entry_or_key, const struct cache_entry, ent);
 132
 133         /*
 134          * For remove_name_hash, find the exact entry (pointer equality); for
 135          * index_file_exists, find all entries with matching hash code and
 136          * decide whether the entry matches in same_name.
 137          */
 138         return remove ? !(ce1 == ce2) : 0;
 139 }
 140
 141 static int lazy_try_threaded = 1;
 142 static int lazy_nr_dir_threads;
 143
 144 /*
 145  * Set a minimum number of cache_entries that we will handle per
 146  * thread and use that to decide how many threads to run (up to
 147  * the number on the system).
 148  *
 149  * For guidance setting the lower per-thread bound, see:
 150  *     t/helper/test-lazy-init-name-hash --analyze
 151  */
 152 #define LAZY_THREAD_COST (2000)
 153
 154 /*
 155  * We use n mutexes to guard n partitions of the "istate->dir_hash"
 156  * hashtable.  Since "find" and "insert" operations will hash to a
 157  * particular bucket and modify/search a single chain, we can say
 158  * that "all chains mod n" are guarded by the same mutex -- rather
 159  * than having a single mutex to guard the entire table.  (This does
 160  * require that we disable "rehashing" on the hashtable.)
 161  *
 162  * So, a larger value here decreases the probability of a collision
 163  * and the time that each thread must wait for the mutex.
 164  */
 165 #define LAZY_MAX_MUTEX   (32)
 166
 167 static pthread_mutex_t *lazy_dir_mutex_array;
 168
 169 /*
 170  * An array of lazy_entry items is used by the n threads in
 171  * the directory parse (first) phase to (lock-free) store the
 172  * intermediate results.  These values are then referenced by
 173  * the 2 threads in the second phase.
 174  */
 175 struct lazy_entry {
 176         struct dir_entry *dir;
 177         unsigned int hash_dir;
 178         unsigned int hash_name;
 179 };
 180
 181 /*
 182  * Decide if we want to use threads (if available) to load
 183  * the hash tables.  We set "lazy_nr_dir_threads" to zero when
 184  * it is not worth it.
 185  */
 186 static int lookup_lazy_params(struct index_state *istate)
 187 {
 188         int nr_cpus;
 189
 190         lazy_nr_dir_threads = 0;
 191
 192         if (!lazy_try_threaded)
 193                 return 0;
 194
 195         /*
 196          * If we are respecting case, just use the original
 197          * code to build the "istate->name_hash".  We don't
 198          * need the complexity here.
 199          */
 200         if (!ignore_case)
 201                 return 0;
 202
 203         nr_cpus = online_cpus();
 204         if (nr_cpus < 2)
 205                 return 0;
 206
 207         if (istate->cache_nr < 2 * LAZY_THREAD_COST)
 208                 return 0;
 209
 210         if (istate->cache_nr < nr_cpus * LAZY_THREAD_COST)
 211                 nr_cpus = istate->cache_nr / LAZY_THREAD_COST;
 212         lazy_nr_dir_threads = nr_cpus;
 213         return lazy_nr_dir_threads;
 214 }
 215
 216 /*
 217  * Initialize n mutexes for use when searching and inserting
 218  * into "istate->dir_hash".  All "dir" threads are trying
 219  * to insert partial pathnames into the hash as they iterate
 220  * over their portions of the index, so lock contention is
 221  * high.
 222  *
 223  * However, the hashmap is going to put items into bucket
 224  * chains based on their hash values.  Use that to create n
 225  * mutexes and lock on mutex[bucket(hash) % n].  This will
 226  * decrease the collision rate by (hopefully) a factor of n.
 227  */
 228 static void init_dir_mutex(void)
 229 {
 230         int j;
 231
 232         CALLOC_ARRAY(lazy_dir_mutex_array, LAZY_MAX_MUTEX);
 233
 234         for (j = 0; j < LAZY_MAX_MUTEX; j++)
 235                 init_recursive_mutex(&lazy_dir_mutex_array[j]);
 236 }
 237
 238 static void cleanup_dir_mutex(void)
 239 {
 240         int j;
 241
 242         for (j = 0; j < LAZY_MAX_MUTEX; j++)
 243                 pthread_mutex_destroy(&lazy_dir_mutex_array[j]);
 244
 245         free(lazy_dir_mutex_array);
 246 }
 247
 248 static void lock_dir_mutex(int j)
 249 {
 250         pthread_mutex_lock(&lazy_dir_mutex_array[j]);
 251 }
 252
 253 static void unlock_dir_mutex(int j)
 254 {
 255         pthread_mutex_unlock(&lazy_dir_mutex_array[j]);
 256 }
 257
 258 static inline int compute_dir_lock_nr(
 259         const struct hashmap *map,
 260         unsigned int hash)
 261 {
 262         return hashmap_bucket(map, hash) % LAZY_MAX_MUTEX;
 263 }
 264
 265 static struct dir_entry *hash_dir_entry_with_parent_and_prefix(
 266         struct index_state *istate,
 267         struct dir_entry *parent,
 268         struct strbuf *prefix)
 269 {
 270         struct dir_entry *dir;
 271         unsigned int hash;
 272         int lock_nr;
 273
 274         /*
 275          * Either we have a parent directory and path with slash(es)
 276          * or the directory is an immediate child of the root directory.
 277          */
 278         assert((parent != NULL) ^ (strchr(prefix->buf, '/') == NULL));
 279
 280         if (parent)
 281                 hash = memihash_cont(parent->ent.hash,
 282                         prefix->buf + parent->namelen,
 283                         prefix->len - parent->namelen);
 284         else
 285                 hash = memihash(prefix->buf, prefix->len);
 286
 287         lock_nr = compute_dir_lock_nr(&istate->dir_hash, hash);
 288         lock_dir_mutex(lock_nr);
 289
 290         dir = find_dir_entry__hash(istate, prefix->buf, prefix->len, hash);
 291         if (!dir) {
 292                 FLEX_ALLOC_MEM(dir, name, prefix->buf, prefix->len);
 293                 hashmap_entry_init(&dir->ent, hash);
 294                 dir->namelen = prefix->len;
 295                 dir->parent = parent;
 296                 hashmap_add(&istate->dir_hash, &dir->ent);
 297
 298                 if (parent) {
 299                         unlock_dir_mutex(lock_nr);
 300
 301                         /* All I really need here is an InterlockedIncrement(&(parent->nr)) */
 302                         lock_nr = compute_dir_lock_nr(&istate->dir_hash, parent->ent.hash);
 303                         lock_dir_mutex(lock_nr);
 304                         parent->nr++;
 305                 }
 306         }
 307
 308         unlock_dir_mutex(lock_nr);
 309
 310         return dir;
 311 }
 312
 313 /*
 314  * handle_range_1() and handle_range_dir() are derived from
 315  * clear_ce_flags_1() and clear_ce_flags_dir() in unpack-trees.c
 316  * and handle the iteration over the entire array of index entries.
 317  * They use recursion for adjacent entries in the same parent
 318  * directory.
 319  */
 320 static int handle_range_1(
 321         struct index_state *istate,
 322         int k_start,
 323         int k_end,
 324         struct dir_entry *parent,
 325         struct strbuf *prefix,
 326         struct lazy_entry *lazy_entries);
 327
 328 static int handle_range_dir(
 329         struct index_state *istate,
 330         int k_start,
 331         int k_end,
 332         struct dir_entry *parent,
 333         struct strbuf *prefix,
 334         struct lazy_entry *lazy_entries,
 335         struct dir_entry **dir_new_out)
 336 {
 337         int rc, k;
 338         int input_prefix_len = prefix->len;
 339         struct dir_entry *dir_new;
 340
 341         dir_new = hash_dir_entry_with_parent_and_prefix(istate, parent, prefix);
 342
 343         strbuf_addch(prefix, '/');
 344
 345         /*
 346          * Scan forward in the index array for index entries having the same
 347          * path prefix (that are also in this directory).
 348          */
 349         if (k_start + 1 >= k_end)
 350                 k = k_end;
 351         else if (strncmp(istate->cache[k_start + 1]->name, prefix->buf, prefix->len) > 0)
 352                 k = k_start + 1;
 353         else if (strncmp(istate->cache[k_end - 1]->name, prefix->buf, prefix->len) == 0)
 354                 k = k_end;
 355         else {
 356                 int begin = k_start;
 357                 int end = k_end;
 358                 assert(begin >= 0);
 359                 while (begin < end) {
 360                         int mid = begin + ((end - begin) >> 1);
 361                         int cmp = strncmp(istate->cache[mid]->name, prefix->buf, prefix->len);
 362                         if (cmp == 0) /* mid has same prefix; look in second part */
 363                                 begin = mid + 1;
 364                         else if (cmp > 0) /* mid is past group; look in first part */
 365                                 end = mid;
 366                         else
 367                                 die("cache entry out of order");
 368                 }
 369                 k = begin;
 370         }
 371
 372         /*
 373          * Recurse and process what we can of this subset [k_start, k).
 374          */
 375         rc = handle_range_1(istate, k_start, k, dir_new, prefix, lazy_entries);
 376
 377         strbuf_setlen(prefix, input_prefix_len);
 378
 379         *dir_new_out = dir_new;
 380         return rc;
 381 }
 382
 383 static int handle_range_1(
 384         struct index_state *istate,
 385         int k_start,
 386         int k_end,
 387         struct dir_entry *parent,
 388         struct strbuf *prefix,
 389         struct lazy_entry *lazy_entries)
 390 {
 391         int input_prefix_len = prefix->len;
 392         int k = k_start;
 393
 394         while (k < k_end) {
 395                 struct cache_entry *ce_k = istate->cache[k];
 396                 const char *name, *slash;
 397
 398                 if (prefix->len && strncmp(ce_k->name, prefix->buf, prefix->len))
 399                         break;
 400
 401                 name = ce_k->name + prefix->len;
 402                 slash = strchr(name, '/');
 403
 404                 if (slash) {
 405                         int len = slash - name;
 406                         int processed;
 407                         struct dir_entry *dir_new;
 408
 409                         strbuf_add(prefix, name, len);
 410                         processed = handle_range_dir(istate, k, k_end, parent, prefix, lazy_entries, &dir_new);
 411                         if (processed) {
 412                                 k += processed;
 413                                 strbuf_setlen(prefix, input_prefix_len);
 414                                 continue;
 415                         }
 416
 417                         strbuf_addch(prefix, '/');
 418                         processed = handle_range_1(istate, k, k_end, dir_new, prefix, lazy_entries);
 419                         k += processed;
 420                         strbuf_setlen(prefix, input_prefix_len);
 421                         continue;
 422                 }
 423
 424                 /*
 425                  * It is too expensive to take a lock to insert "ce_k"
 426                  * into "istate->name_hash" and increment the ref-count
 427                  * on the "parent" dir.  So we defer actually updating
 428                  * permanent data structures until phase 2 (where we
 429                  * can change the locking requirements) and simply
 430                  * accumulate our current results into the lazy_entries
 431                  * data array).
 432                  *
 433                  * We do not need to lock the lazy_entries array because
 434                  * we have exclusive access to the cells in the range
 435                  * [k_start,k_end) that this thread was given.
 436                  */
 437                 lazy_entries[k].dir = parent;
 438                 if (parent) {
 439                         lazy_entries[k].hash_name = memihash_cont(
 440                                 parent->ent.hash,
 441                                 ce_k->name + parent->namelen,
 442                                 ce_namelen(ce_k) - parent->namelen);
 443                         lazy_entries[k].hash_dir = parent->ent.hash;
 444                 } else {
 445                         lazy_entries[k].hash_name = memihash(ce_k->name, ce_namelen(ce_k));
 446                 }
 447
 448                 k++;
 449         }
 450
 451         return k - k_start;
 452 }
 453
 454 struct lazy_dir_thread_data {
 455         pthread_t pthread;
 456         struct index_state *istate;
 457         struct lazy_entry *lazy_entries;
 458         int k_start;
 459         int k_end;
 460 };
 461
 462 static void *lazy_dir_thread_proc(void *_data)
 463 {
 464         struct lazy_dir_thread_data *d = _data;
 465         struct strbuf prefix = STRBUF_INIT;
 466         handle_range_1(d->istate, d->k_start, d->k_end, NULL, &prefix, d->lazy_entries);
 467         strbuf_release(&prefix);
 468         return NULL;
 469 }
 470
 471 struct lazy_name_thread_data {
 472         pthread_t pthread;
 473         struct index_state *istate;
 474         struct lazy_entry *lazy_entries;
 475 };
 476
 477 static void *lazy_name_thread_proc(void *_data)
 478 {
 479         struct lazy_name_thread_data *d = _data;
 480         int k;
 481
 482         for (k = 0; k < d->istate->cache_nr; k++) {
 483                 struct cache_entry *ce_k = d->istate->cache[k];
 484                 ce_k->ce_flags |= CE_HASHED;
 485                 hashmap_entry_init(&ce_k->ent, d->lazy_entries[k].hash_name);
 486                 hashmap_add(&d->istate->name_hash, &ce_k->ent);
 487         }
 488
 489         return NULL;
 490 }
 491
 492 static inline void lazy_update_dir_ref_counts(
 493         struct index_state *istate,
 494         struct lazy_entry *lazy_entries)
 495 {
 496         int k;
 497
 498         for (k = 0; k < istate->cache_nr; k++) {
 499                 if (lazy_entries[k].dir)
 500                         lazy_entries[k].dir->nr++;
 501         }
 502 }
 503
 504 static void threaded_lazy_init_name_hash(
 505         struct index_state *istate)
 506 {
 507         int err;
 508         int nr_each;
 509         int k_start;
 510         int t;
 511         struct lazy_entry *lazy_entries;
 512         struct lazy_dir_thread_data *td_dir;
 513         struct lazy_name_thread_data *td_name;
 514
 515         if (!HAVE_THREADS)
 516                 return;
 517
 518         k_start = 0;
 519         nr_each = DIV_ROUND_UP(istate->cache_nr, lazy_nr_dir_threads);
 520
 521         CALLOC_ARRAY(lazy_entries, istate->cache_nr);
 522         CALLOC_ARRAY(td_dir, lazy_nr_dir_threads);
 523         CALLOC_ARRAY(td_name, 1);
 524
 525         init_dir_mutex();
 526
 527         /*
 528          * Phase 1:
 529          * Build "istate->dir_hash" using n "dir" threads (and a read-only index).
 530          */
 531         for (t = 0; t < lazy_nr_dir_threads; t++) {
 532                 struct lazy_dir_thread_data *td_dir_t = td_dir + t;
 533                 td_dir_t->istate = istate;
 534                 td_dir_t->lazy_entries = lazy_entries;
 535                 td_dir_t->k_start = k_start;
 536                 k_start += nr_each;
 537                 if (k_start > istate->cache_nr)
 538                         k_start = istate->cache_nr;
 539                 td_dir_t->k_end = k_start;
 540                 err = pthread_create(&td_dir_t->pthread, NULL, lazy_dir_thread_proc, td_dir_t);
 541                 if (err)
 542                         die(_("unable to create lazy_dir thread: %s"), strerror(err));
 543         }
 544         for (t = 0; t < lazy_nr_dir_threads; t++) {
 545                 struct lazy_dir_thread_data *td_dir_t = td_dir + t;
 546                 if (pthread_join(td_dir_t->pthread, NULL))
 547                         die("unable to join lazy_dir_thread");
 548         }
 549
 550         /*
 551          * Phase 2:
 552          * Iterate over all index entries and add them to the "istate->name_hash"
 553          * using a single "name" background thread.
 554          * (Testing showed it wasn't worth running more than 1 thread for this.)
 555          *
 556          * Meanwhile, finish updating the parent directory ref-counts for each
 557          * index entry using the current thread.  (This step is very fast and
 558          * doesn't need threading.)
 559          */
 560         td_name->istate = istate;
 561         td_name->lazy_entries = lazy_entries;
 562         err = pthread_create(&td_name->pthread, NULL, lazy_name_thread_proc, td_name);
 563         if (err)
 564                 die(_("unable to create lazy_name thread: %s"), strerror(err));
 565
 566         lazy_update_dir_ref_counts(istate, lazy_entries);
 567
 568         err = pthread_join(td_name->pthread, NULL);
 569         if (err)
 570                 die(_("unable to join lazy_name thread: %s"), strerror(err));
 571
 572         cleanup_dir_mutex();
 573
 574         free(td_name);
 575         free(td_dir);
 576         free(lazy_entries);
 577 }
 578
 579 static void lazy_init_name_hash(struct index_state *istate)
 580 {
 581
 582         if (istate->name_hash_initialized)
 583                 return;
 584         trace_performance_enter();
 585         trace2_region_enter("index", "name-hash-init", istate->repo);
 586         hashmap_init(&istate->name_hash, cache_entry_cmp, NULL, istate->cache_nr);
 587         hashmap_init(&istate->dir_hash, dir_entry_cmp, NULL, istate->cache_nr);
 588
 589         if (lookup_lazy_params(istate)) {
 590                 /*
 591                  * Disable item counting and automatic rehashing because
 592                  * we do per-chain (mod n) locking rather than whole hashmap
 593                  * locking and we need to prevent the table-size from changing
 594                  * and bucket items from being redistributed.
 595                  */
 596                 hashmap_disable_item_counting(&istate->dir_hash);
 597                 threaded_lazy_init_name_hash(istate);
 598                 hashmap_enable_item_counting(&istate->dir_hash);
 599         } else {
 600                 int nr;
 601                 for (nr = 0; nr < istate->cache_nr; nr++)
 602                         hash_index_entry(istate, istate->cache[nr]);
 603         }
 604
 605         istate->name_hash_initialized = 1;
 606         trace2_region_leave("index", "name-hash-init", istate->repo);
 607         trace_performance_leave("initialize name hash");
 608 }
 609
 610 /*
 611  * A test routine for t/helper/ sources.
 612  *
 613  * Returns the number of threads used or 0 when
 614  * the non-threaded code path was used.
 615  *
 616  * Requesting threading WILL NOT override guards
 617  * in lookup_lazy_params().
 618  */
 619 int test_lazy_init_name_hash(struct index_state *istate, int try_threaded)
 620 {
 621         lazy_nr_dir_threads = 0;
 622         lazy_try_threaded = try_threaded;
 623
 624         lazy_init_name_hash(istate);
 625
 626         return lazy_nr_dir_threads;
 627 }
 628
 629 void add_name_hash(struct index_state *istate, struct cache_entry *ce)
 630 {
 631         if (istate->name_hash_initialized)
 632                 hash_index_entry(istate, ce);
 633 }
 634
 635 void remove_name_hash(struct index_state *istate, struct cache_entry *ce)
 636 {
 637         if (!istate->name_hash_initialized || !(ce->ce_flags & CE_HASHED))
 638                 return;
 639         ce->ce_flags &= ~CE_HASHED;
 640         hashmap_remove(&istate->name_hash, &ce->ent, ce);
 641
 642         if (ignore_case)
 643                 remove_dir_entry(istate, ce);
 644 }
 645
 646 static int slow_same_name(const char *name1, int len1, const char *name2, int len2)
 647 {
 648         if (len1 != len2)
 649                 return 0;
 650
 651         while (len1) {
 652                 unsigned char c1 = *name1++;
 653                 unsigned char c2 = *name2++;
 654                 len1--;
 655                 if (c1 != c2) {
 656                         c1 = toupper(c1);
 657                         c2 = toupper(c2);
 658                         if (c1 != c2)
 659                                 return 0;
 660                 }
 661         }
 662         return 1;
 663 }
 664
 665 static int same_name(const struct cache_entry *ce, const char *name, int namelen, int icase)
 666 {
 667         int len = ce_namelen(ce);
 668
 669         /*
 670          * Always do exact compare, even if we want a case-ignoring comparison;
 671          * we do the quick exact one first, because it will be the common case.
 672          */
 673         if (len == namelen && !memcmp(name, ce->name, len))
 674                 return 1;
 675
 676         if (!icase)
 677                 return 0;
 678
 679         return slow_same_name(name, namelen, ce->name, len);
 680 }
 681
 682 int index_dir_exists(struct index_state *istate, const char *name, int namelen)
 683 {
 684         struct dir_entry *dir;
 685
 686         lazy_init_name_hash(istate);
 687         expand_to_path(istate, name, namelen, 0);
 688         dir = find_dir_entry(istate, name, namelen);
 689         return dir && dir->nr;
 690 }
 691
 692 void adjust_dirname_case(struct index_state *istate, char *name)
 693 {
 694         const char *startPtr = name;
 695         const char *ptr = startPtr;
 696
 697         lazy_init_name_hash(istate);
 698         expand_to_path(istate, name, strlen(name), 0);
 699         while (*ptr) {
 700                 while (*ptr && *ptr != '/')
 701                         ptr++;
 702
 703                 if (*ptr == '/') {
 704                         struct dir_entry *dir;
 705
 706                         dir = find_dir_entry(istate, name, ptr - name);
 707                         if (dir) {
 708                                 memcpy((void *)startPtr, dir->name + (startPtr - name), ptr - startPtr);
 709                                 startPtr = ptr + 1;
 710                         }
 711                         ptr++;
 712                 }
 713         }
 714 }
 715
 716 struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
 717 {
 718         struct cache_entry *ce;
 719         unsigned int hash = memihash(name, namelen);
 720
 721         lazy_init_name_hash(istate);
 722         expand_to_path(istate, name, namelen, icase);
 723
 724         ce = hashmap_get_entry_from_hash(&istate->name_hash, hash, NULL,
 725                                          struct cache_entry, ent);
 726         hashmap_for_each_entry_from(&istate->name_hash, ce, ent) {
 727                 if (same_name(ce, name, namelen, icase))
 728                         return ce;
 729         }
 730         return NULL;
 731 }
 732
 733 void free_name_hash(struct index_state *istate)
 734 {
 735         if (!istate->name_hash_initialized)
 736                 return;
 737         istate->name_hash_initialized = 0;
 738
 739         hashmap_clear(&istate->name_hash);
 740         hashmap_clear_and_free(&istate->dir_hash, struct dir_entry, ent);
 741 }