libswfdec/swfdec_cache.c

   1 /* Swfdec
   2  * Copyright (C) 2005 David Schleef <ds@schleef.org>
   3  *               2007 Benjamin Otte <otte@gnome.org>
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor,
  18  * Boston, MA  02110-1301  USA
  19  */
  20
  21 #ifdef HAVE_CONFIG_H
  22 #include "config.h"
  23 #endif
  24
  25 #include "swfdec_cache.h"
  26 #include "swfdec_debug.h"
  27
  28 SwfdecCache *
  29 swfdec_cache_new (guint max_size)
  30 {
  31   SwfdecCache *cache;
  32
  33   g_return_val_if_fail (max_size > 0, NULL);
  34
  35   cache = g_new0 (SwfdecCache, 1);
  36   cache->refcount = 1;
  37   cache->queue = g_queue_new ();
  38   cache->max_size = max_size;
  39
  40   return cache;
  41 }
  42
  43 void
  44 swfdec_cache_ref (SwfdecCache *cache)
  45 {
  46   g_return_if_fail (cache != NULL);
  47
  48   cache->refcount++;
  49 }
  50
  51 void
  52 swfdec_cache_unref (SwfdecCache *cache)
  53 {
  54   g_return_if_fail (cache != NULL);
  55   g_return_if_fail (cache->refcount > 0);
  56
  57   cache->refcount--;
  58   if (cache->refcount > 0)
  59     return;
  60
  61   g_queue_free (cache->queue);
  62   g_free (cache);
  63 }
  64
  65 guint
  66 swfdec_cache_get_usage (SwfdecCache *cache)
  67 {
  68   g_return_val_if_fail (cache != NULL, 0);
  69
  70   return cache->usage;
  71 }
  72
  73 void
  74 swfdec_cache_shrink (SwfdecCache *cache, guint max_usage)
  75 {
  76   g_return_if_fail (cache != NULL);
  77
  78   while (cache->usage > max_usage) {
  79     SwfdecCacheHandle *handle = g_queue_pop_tail (cache->queue);
  80     g_assert (handle);
  81     cache->usage -= handle->size;
  82     SWFDEC_LOG ("%p removing %p (%u => %u)", cache, handle,
  83         cache->usage + handle->size, cache->usage);
  84     handle->unload (handle);
  85   }
  86 }
  87
  88 /**
  89  * swfdec_cache_add_handle:
  90  * @cache: a #SwfdecCache
  91  * @handle: a handle to add
  92  *
  93  * Adds @handle to @cache. If not enough space is available in the cache,
  94  * the cache will unload existing handles first. If handle is already part
  95  * of cache, its usage information will be updated. This will make it less
  96  * likely that it gets unloaded.
  97  **/
  98 void
  99 swfdec_cache_add_handle (SwfdecCache *cache, const SwfdecCacheHandle *handle)
 100 {
 101   GList *list;
 102
 103   g_return_if_fail (cache != NULL);
 104   g_return_if_fail (handle != NULL);
 105   g_return_if_fail (handle->size > 0);
 106   g_return_if_fail (handle->unload != NULL);
 107
 108   list = g_queue_find (cache->queue, handle);
 109   if (list) {
 110     /* bring to front of queue */
 111     g_queue_unlink (cache->queue, list);
 112     g_queue_push_head_link (cache->queue, list);
 113   } else {
 114     swfdec_cache_shrink (cache, cache->max_size - handle->size);
 115     g_queue_push_head (cache->queue, (gpointer) handle);
 116     cache->usage += handle->size;
 117     SWFDEC_LOG ("%p adding %p (%u => %u)", cache, handle,
 118         cache->usage - handle->size, cache->usage);
 119   }
 120 }
 121
 122 /**
 123  * swfdec_cache_remove_handle:
 124  * @cache: a #SwfdecCache
 125  * @handle: the handle to remove
 126  *
 127  * Removes the given @handle from the @cache, if it was part of it. If the
 128  * handle wasn't part of the cache, nothing happens.
 129  **/
 130 void
 131 swfdec_cache_remove_handle (SwfdecCache *cache, const SwfdecCacheHandle *handle)
 132 {
 133   GList *list;
 134
 135   g_return_if_fail (cache != NULL);
 136   g_return_if_fail (handle != NULL);
 137   g_return_if_fail (handle->size > 0);
 138   g_return_if_fail (handle->unload != NULL);
 139
 140   list = g_queue_find (cache->queue, handle);
 141   if (list) {
 142     g_queue_delete_link (cache->queue, list);
 143     cache->usage -= handle->size;
 144     SWFDEC_LOG ("%p removing %p (%u => %u)", cache, handle,
 145         cache->usage + handle->size, cache->usage);
 146   }
 147 }