Name
Caches -- caches allow sharing of complex data structures to save resources.
Synopsis
| 
#include <glib.h>
struct      GCache;
GCache*     g_cache_new                     (GCacheNewFunc value_new_func,
                                             GCacheDestroyFunc value_destroy_func,
                                             GCacheDupFunc key_dup_func,
                                             GCacheDestroyFunc key_destroy_func,
                                             GHashFunc hash_key_func,
                                             GHashFunc hash_value_func,
                                             GEqualFunc key_equal_func);
gpointer    g_cache_insert                  (GCache *cache,
                                             gpointer key);
void        g_cache_remove                  (GCache *cache,
                                             gconstpointer value);
void        g_cache_destroy                 (GCache *cache);
void        g_cache_key_foreach             (GCache *cache,
                                             GHFunc func,
                                             gpointer user_data);
void        g_cache_value_foreach           (GCache *cache,
                                             GHFunc func,
                                             gpointer user_data);
void        (*GCacheDestroyFunc)            (gpointer value);
gpointer    (*GCacheDupFunc)                (gpointer value);
gpointer    (*GCacheNewFunc)                (gpointer key); | 
Description
A GCache allows sharing of complex data structures, in order to save
system resources.
GTK+ uses caches for GtkStyles and GdkGCs. These consume a lot of
resources, so a GCache is used to see if a GtkStyle or GdkGC with the
required properties already exists. If it does, then the existing
object is used instead of creating a new one.
GCache uses keys and values.
A GCache key describes the properties of a particular resource.
A GCache value is the actual resource.
Details
struct GCache
The GCache struct is an opaque data structure containing information about
a GCache. It should only be accessed via the following functions.
g_cache_new ()
Creates a new GCache.
g_cache_insert ()
Gets the value corresponding to the given key, creating it if necessary.
It first checks if the value already exists in the GCache, by using
the key_equal_func function passed to g_cache_new().
If it does already exist it is returned, and its reference count is increased
by one.
If the value does not currently exist, if is created by calling the
value_new_func. The key is duplicated by calling
key_dup_func and the duplicated key and value are inserted
into the GCache.
g_cache_remove ()
Decreases the reference count of the given value.
If it drops to 0 then the value and its corresponding key are destroyed,
using the value_destroy_func and key_destroy_func passed to g_cache_new().
g_cache_destroy ()
| void        g_cache_destroy                 (GCache *cache); | 
Frees the memory allocated for the GCache.
Note that it does not destroy the keys and values which were contained in the
GCache.
g_cache_key_foreach ()
Calls the given function for each of the keys in the GCache.
g_cache_value_foreach ()
Calls the given function for each of the values in the GCache.
GCacheDestroyFunc ()
| void        (*GCacheDestroyFunc)            (gpointer value); | 
Specifies the type of the value_destroy_func and key_destroy_func functions
passed to g_cache_new().
The functions are passed a pointer to the GCache key or GCache value and
should free any memory and other resources associated with it.
GCacheDupFunc ()
Specifies the type of the key_dup_func function passed to g_cache_new().
The function is passed a key (not a value as the prototype implies) and
should return a duplicate of the key.
GCacheNewFunc ()
Specifies the type of the value_new_func function passed to g_cache_new().
It is passed a GCache key and should create the value corresponding to the
key.