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/*
* name-hash.c
*
* Hashing names in the index state
*
* Copyright (C) 2008 Linus Torvalds
*/
#define NO_THE_INDEX_COMPATIBILITY_MACROS
#include "cache.h"
struct dir_entry {
struct hashmap_entry ent;
struct dir_entry *parent;
struct cache_entry *ce;
int nr;
unsigned int namelen;
};
static int dir_entry_cmp(const struct dir_entry *e1,
const struct dir_entry *e2, const char *name)
{
return e1->namelen != e2->namelen || strncasecmp(e1->ce->name,
name ? name : e2->ce->name, e1->namelen);
}
static struct dir_entry *find_dir_entry(struct index_state *istate,
const char *name, unsigned int namelen)
{
struct dir_entry key;
hashmap_entry_init(&key, memihash(name, namelen));
key.namelen = namelen;
return hashmap_get(&istate->dir_hash, &key, name);
}
static struct dir_entry *hash_dir_entry(struct index_state *istate,
struct cache_entry *ce, int namelen)
{
/*
* Throw each directory component in the hash for quick lookup
* during a git status. Directory components are stored without their
* closing slash. Despite submodules being a directory, they never
* reach this point, because they are stored
* in index_state.name_hash (as ordinary cache_entries).
*
* Note that the cache_entry stored with the dir_entry merely
* supplies the name of the directory (up to dir_entry.namelen). We
* track the number of 'active' files in a directory in dir_entry.nr,
* so we can tell if the directory is still relevant, e.g. for git
* status. However, if cache_entries are removed, we cannot pinpoint
* an exact cache_entry that's still active. It is very possible that
* multiple dir_entries point to the same cache_entry.
*/
struct dir_entry *dir;
/* get length of parent directory */
while (namelen > 0 && !is_dir_sep(ce->name[namelen - 1]))
namelen--;
if (namelen <= 0)
return NULL;
namelen--;
/* lookup existing entry for that directory */
dir = find_dir_entry(istate, ce->name, namelen);
if (!dir) {
/* not found, create it and add to hash table */
dir = xcalloc(1, sizeof(struct dir_entry));
hashmap_entry_init(dir, memihash(ce->name, namelen));
dir->namelen = namelen;
dir->ce = ce;
hashmap_add(&istate->dir_hash, dir);
/* recursively add missing parent directories */
dir->parent = hash_dir_entry(istate, ce, namelen);
}
return dir;
}
static void add_dir_entry(struct index_state *istate, struct cache_entry *ce)
{
/* Add reference to the directory entry (and parents if 0). */
struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
while (dir && !(dir->nr++))
dir = dir->parent;
}
static void remove_dir_entry(struct index_state *istate, struct cache_entry *ce)
{
/*
* Release reference to the directory entry. If 0, remove and continue
* with parent directory.
*/
struct dir_entry *dir = hash_dir_entry(istate, ce, ce_namelen(ce));
while (dir && !(--dir->nr)) {
struct dir_entry *parent = dir->parent;
hashmap_remove(&istate->dir_hash, dir, NULL);
free(dir);
dir = parent;
}
}
static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
{
if (ce->ce_flags & CE_HASHED)
return;
ce->ce_flags |= CE_HASHED;
hashmap_entry_init(ce, memihash(ce->name, ce_namelen(ce)));
hashmap_add(&istate->name_hash, ce);
if (ignore_case)
add_dir_entry(istate, ce);
}
static int cache_entry_cmp(const struct cache_entry *ce1,
const struct cache_entry *ce2, const void *remove)
{
/*
* For remove_name_hash, find the exact entry (pointer equality); for
* index_file_exists, find all entries with matching hash code and
* decide whether the entry matches in same_name.
*/
return remove ? !(ce1 == ce2) : 0;
}
static void lazy_init_name_hash(struct index_state *istate)
{
int nr;
if (istate->name_hash_initialized)
return;
hashmap_init(&istate->name_hash, (hashmap_cmp_fn) cache_entry_cmp,
istate->cache_nr);
hashmap_init(&istate->dir_hash, (hashmap_cmp_fn) dir_entry_cmp, 0);
for (nr = 0; nr < istate->cache_nr; nr++)
hash_index_entry(istate, istate->cache[nr]);
istate->name_hash_initialized = 1;
}
void add_name_hash(struct index_state *istate, struct cache_entry *ce)
{
if (istate->name_hash_initialized)
hash_index_entry(istate, ce);
}
void remove_name_hash(struct index_state *istate, struct cache_entry *ce)
{
if (!istate->name_hash_initialized || !(ce->ce_flags & CE_HASHED))
return;
ce->ce_flags &= ~CE_HASHED;
hashmap_remove(&istate->name_hash, ce, ce);
if (ignore_case)
remove_dir_entry(istate, ce);
}
static int slow_same_name(const char *name1, int len1, const char *name2, int len2)
{
if (len1 != len2)
return 0;
while (len1) {
unsigned char c1 = *name1++;
unsigned char c2 = *name2++;
len1--;
if (c1 != c2) {
c1 = toupper(c1);
c2 = toupper(c2);
if (c1 != c2)
return 0;
}
}
return 1;
}
static int same_name(const struct cache_entry *ce, const char *name, int namelen, int icase)
{
int len = ce_namelen(ce);
/*
* Always do exact compare, even if we want a case-ignoring comparison;
* we do the quick exact one first, because it will be the common case.
*/
if (len == namelen && !memcmp(name, ce->name, len))
return 1;
if (!icase)
return 0;
return slow_same_name(name, namelen, ce->name, len);
}
struct cache_entry *index_dir_exists(struct index_state *istate, const char *name, int namelen)
{
struct cache_entry *ce;
struct dir_entry *dir;
lazy_init_name_hash(istate);
dir = find_dir_entry(istate, name, namelen);
if (dir && dir->nr)
return dir->ce;
/*
* It might be a submodule. Unlike plain directories, which are stored
* in the dir-hash, submodules are stored in the name-hash, so check
* there, as well.
*/
ce = index_file_exists(istate, name, namelen, 1);
if (ce && S_ISGITLINK(ce->ce_mode))
return ce;
return NULL;
}
struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
{
struct cache_entry *ce;
lazy_init_name_hash(istate);
ce = hashmap_get_from_hash(&istate->name_hash,
memihash(name, namelen), NULL);
while (ce) {
if (same_name(ce, name, namelen, icase))
return ce;
ce = hashmap_get_next(&istate->name_hash, ce);
}
return NULL;
}
void free_name_hash(struct index_state *istate)
{
if (!istate->name_hash_initialized)
return;
istate->name_hash_initialized = 0;
hashmap_free(&istate->name_hash, 0);
hashmap_free(&istate->dir_hash, 1);
}
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