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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef CAIRO_CACHE_PRIVATE_H
#define CAIRO_CACHE_PRIVATE_H
#include "cairo-compiler-private.h"
#include "cairo-types-private.h"
/**
* cairo_cache_entry_t:
*
* A #cairo_cache_entry_t contains both a key and a value for
* #cairo_cache_t. User-derived types for #cairo_cache_entry_t must
* have a #cairo_cache_entry_t as their first field. For example:
*
* typedef _my_entry {
* cairo_cache_entry_t base;
* ... Remainder of key and value fields here ..
* } my_entry_t;
*
* which then allows a pointer to my_entry_t to be passed to any of
* the #cairo_cache_t functions as follows without requiring a cast:
*
* _cairo_cache_insert (cache, &my_entry->base, size);
*
* IMPORTANT: The caller is responsible for initializing
* my_entry->base.hash with a hash code derived from the key. The
* essential property of the hash code is that keys_equal must never
* return %TRUE for two keys that have different hashes. The best hash
* code will reduce the frequency of two keys with the same code for
* which keys_equal returns %FALSE.
*
* The user must also initialize my_entry->base.size to indicate
* the size of the current entry. What units to use for size is
* entirely up to the caller, (though the same units must be used for
* the max_size parameter passed to _cairo_cache_create()). If all
* entries are close to the same size, the simplest thing to do is to
* just use units of "entries", (eg. set size==1 in all entries and
* set max_size to the number of entries which you want to be saved
* in the cache).
*
* Which parts of the entry make up the "key" and which part make up
* the value are entirely up to the caller, (as determined by the
* computation going into base.hash as well as the keys_equal
* function). A few of the #cairo_cache_t functions accept an entry which
* will be used exclusively as a "key", (indicated by a parameter name
* of key). In these cases, the value-related fields of the entry need
* not be initialized if so desired.
**/
typedef struct _cairo_cache_entry {
uintptr_t hash;
unsigned long size;
} cairo_cache_entry_t;
typedef cairo_bool_t (*cairo_cache_predicate_func_t) (const void *entry);
struct _cairo_cache {
cairo_hash_table_t *hash_table;
cairo_cache_predicate_func_t predicate;
cairo_destroy_func_t entry_destroy;
unsigned long max_size;
unsigned long size;
int freeze_count;
};
typedef cairo_bool_t
(*cairo_cache_keys_equal_func_t) (const void *key_a, const void *key_b);
typedef void
(*cairo_cache_callback_func_t) (void *entry,
void *closure);
cairo_private cairo_status_t
_cairo_cache_init (cairo_cache_t *cache,
cairo_cache_keys_equal_func_t keys_equal,
cairo_cache_predicate_func_t predicate,
cairo_destroy_func_t entry_destroy,
unsigned long max_size);
cairo_private void
_cairo_cache_fini (cairo_cache_t *cache);
cairo_private void
_cairo_cache_freeze (cairo_cache_t *cache);
cairo_private void
_cairo_cache_thaw (cairo_cache_t *cache);
cairo_private void *
_cairo_cache_lookup (cairo_cache_t *cache,
cairo_cache_entry_t *key);
cairo_private cairo_status_t
_cairo_cache_insert (cairo_cache_t *cache,
cairo_cache_entry_t *entry);
cairo_private void
_cairo_cache_remove (cairo_cache_t *cache,
cairo_cache_entry_t *entry);
cairo_private void
_cairo_cache_foreach (cairo_cache_t *cache,
cairo_cache_callback_func_t cache_callback,
void *closure);
#endif
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