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ab73a9d119
Hashmap entries are typically looked up by just a key. The hashmap_get() API expects an initialized entry structure instead, to support compound keys. This flexibility is currently only needed by find_dir_entry() in name-hash.c (and compat/win32/fscache.c in the msysgit fork). All other (currently five) call sites of hashmap_get() have to set up a near emtpy entry structure, resulting in duplicate code like this: struct hashmap_entry keyentry; hashmap_entry_init(&keyentry, hash(key)); return hashmap_get(map, &keyentry, key); Add a hashmap_get_from_hash() API that allows hashmap lookups by just specifying the key and its hash code, i.e.: return hashmap_get_from_hash(map, hash(key), key); Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
237 lines
6.2 KiB
C
237 lines
6.2 KiB
C
/*
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* name-hash.c
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*
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* Hashing names in the index state
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*
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* Copyright (C) 2008 Linus Torvalds
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*/
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#define NO_THE_INDEX_COMPATIBILITY_MACROS
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#include "cache.h"
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struct dir_entry {
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struct hashmap_entry ent;
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struct dir_entry *parent;
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struct cache_entry *ce;
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int nr;
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unsigned int namelen;
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};
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static int dir_entry_cmp(const struct dir_entry *e1,
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const struct dir_entry *e2, const char *name)
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{
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return e1->namelen != e2->namelen || strncasecmp(e1->ce->name,
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name ? name : e2->ce->name, e1->namelen);
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}
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static struct dir_entry *find_dir_entry(struct index_state *istate,
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const char *name, unsigned int namelen)
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{
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struct dir_entry key;
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hashmap_entry_init(&key, memihash(name, namelen));
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key.namelen = namelen;
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return hashmap_get(&istate->dir_hash, &key, name);
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}
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static struct dir_entry *hash_dir_entry(struct index_state *istate,
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struct cache_entry *ce, int namelen)
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{
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/*
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* Throw each directory component in the hash for quick lookup
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* during a git status. Directory components are stored without their
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* closing slash. Despite submodules being a directory, they never
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* reach this point, because they are stored
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* in index_state.name_hash (as ordinary cache_entries).
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*
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* Note that the cache_entry stored with the dir_entry merely
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* supplies the name of the directory (up to dir_entry.namelen). We
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* track the number of 'active' files in a directory in dir_entry.nr,
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* so we can tell if the directory is still relevant, e.g. for git
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* status. However, if cache_entries are removed, we cannot pinpoint
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* an exact cache_entry that's still active. It is very possible that
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* multiple dir_entries point to the same cache_entry.
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*/
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struct dir_entry *dir;
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/* get length of parent directory */
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while (namelen > 0 && !is_dir_sep(ce->name[namelen - 1]))
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namelen--;
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if (namelen <= 0)
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return NULL;
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namelen--;
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/* lookup existing entry for that directory */
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dir = find_dir_entry(istate, ce->name, namelen);
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if (!dir) {
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/* not found, create it and add to hash table */
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dir = xcalloc(1, sizeof(struct dir_entry));
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hashmap_entry_init(dir, memihash(ce->name, namelen));
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dir->namelen = namelen;
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dir->ce = ce;
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hashmap_add(&istate->dir_hash, dir);
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/* recursively add missing parent directories */
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dir->parent = hash_dir_entry(istate, ce, namelen);
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}
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return dir;
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}
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static void add_dir_entry(struct index_state *istate, struct cache_entry *ce)
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{
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/* Add reference to the directory entry (and parents if 0). */
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struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
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while (dir && !(dir->nr++))
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dir = dir->parent;
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}
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static void remove_dir_entry(struct index_state *istate, struct cache_entry *ce)
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{
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/*
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* Release reference to the directory entry. If 0, remove and continue
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* with parent directory.
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*/
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struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
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while (dir && !(--dir->nr)) {
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struct dir_entry *parent = dir->parent;
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hashmap_remove(&istate->dir_hash, dir, NULL);
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free(dir);
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dir = parent;
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}
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}
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static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
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{
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if (ce->ce_flags & CE_HASHED)
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return;
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ce->ce_flags |= CE_HASHED;
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hashmap_entry_init(ce, memihash(ce->name, ce_namelen(ce)));
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hashmap_add(&istate->name_hash, ce);
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if (ignore_case)
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add_dir_entry(istate, ce);
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}
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static int cache_entry_cmp(const struct cache_entry *ce1,
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const struct cache_entry *ce2, const void *remove)
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{
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/*
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* For remove_name_hash, find the exact entry (pointer equality); for
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* index_file_exists, find all entries with matching hash code and
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* decide whether the entry matches in same_name.
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*/
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return remove ? !(ce1 == ce2) : 0;
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}
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static void lazy_init_name_hash(struct index_state *istate)
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{
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int nr;
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if (istate->name_hash_initialized)
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return;
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hashmap_init(&istate->name_hash, (hashmap_cmp_fn) cache_entry_cmp,
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istate->cache_nr);
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hashmap_init(&istate->dir_hash, (hashmap_cmp_fn) dir_entry_cmp, 0);
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for (nr = 0; nr < istate->cache_nr; nr++)
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hash_index_entry(istate, istate->cache[nr]);
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istate->name_hash_initialized = 1;
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}
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void add_name_hash(struct index_state *istate, struct cache_entry *ce)
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{
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if (istate->name_hash_initialized)
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hash_index_entry(istate, ce);
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}
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void remove_name_hash(struct index_state *istate, struct cache_entry *ce)
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{
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if (!istate->name_hash_initialized || !(ce->ce_flags & CE_HASHED))
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return;
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ce->ce_flags &= ~CE_HASHED;
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hashmap_remove(&istate->name_hash, ce, ce);
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if (ignore_case)
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remove_dir_entry(istate, ce);
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}
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static int slow_same_name(const char *name1, int len1, const char *name2, int len2)
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{
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if (len1 != len2)
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return 0;
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while (len1) {
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unsigned char c1 = *name1++;
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unsigned char c2 = *name2++;
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len1--;
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if (c1 != c2) {
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c1 = toupper(c1);
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c2 = toupper(c2);
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if (c1 != c2)
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return 0;
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}
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}
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return 1;
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}
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static int same_name(const struct cache_entry *ce, const char *name, int namelen, int icase)
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{
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int len = ce_namelen(ce);
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/*
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* Always do exact compare, even if we want a case-ignoring comparison;
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* we do the quick exact one first, because it will be the common case.
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*/
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if (len == namelen && !memcmp(name, ce->name, len))
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return 1;
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if (!icase)
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return 0;
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return slow_same_name(name, namelen, ce->name, len);
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}
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struct cache_entry *index_dir_exists(struct index_state *istate, const char *name, int namelen)
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{
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struct cache_entry *ce;
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struct dir_entry *dir;
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lazy_init_name_hash(istate);
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dir = find_dir_entry(istate, name, namelen);
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if (dir && dir->nr)
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return dir->ce;
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/*
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* It might be a submodule. Unlike plain directories, which are stored
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* in the dir-hash, submodules are stored in the name-hash, so check
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* there, as well.
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*/
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ce = index_file_exists(istate, name, namelen, 1);
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if (ce && S_ISGITLINK(ce->ce_mode))
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return ce;
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return NULL;
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}
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struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
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{
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struct cache_entry *ce;
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lazy_init_name_hash(istate);
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ce = hashmap_get_from_hash(&istate->name_hash,
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memihash(name, namelen), NULL);
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while (ce) {
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if (same_name(ce, name, namelen, icase))
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return ce;
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ce = hashmap_get_next(&istate->name_hash, ce);
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}
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return NULL;
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}
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void free_name_hash(struct index_state *istate)
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{
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if (!istate->name_hash_initialized)
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return;
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istate->name_hash_initialized = 0;
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hashmap_free(&istate->name_hash, 0);
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hashmap_free(&istate->dir_hash, 1);
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}
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