LayerCache.h revision fb8b763f762ae21923c58d64caa729b012f40e05 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_UI_LAYER_CACHE_H
18#define ANDROID_UI_LAYER_CACHE_H
19
20#include "Layer.h"
21#include "GenerationCache.h"
22
23namespace android {
24namespace uirenderer {
25
26///////////////////////////////////////////////////////////////////////////////
27// Defines
28///////////////////////////////////////////////////////////////////////////////
29
30// Debug
31#define DEBUG_LAYERS 0
32
33// Debug
34#if DEBUG_LAYERS
35    #define LAYER_LOGD(...) LOGD(__VA_ARGS__)
36#else
37    #define LAYER_LOGD(...)
38#endif
39
40///////////////////////////////////////////////////////////////////////////////
41// Cache
42///////////////////////////////////////////////////////////////////////////////
43
44class LayerCache: public OnEntryRemoved<LayerSize, Layer*> {
45public:
46    LayerCache();
47    LayerCache(uint32_t maxByteSize);
48    ~LayerCache();
49
50    /**
51     * Used as a callback when an entry is removed from the cache.
52     * Do not invoke directly.
53     */
54    void operator()(LayerSize& size, Layer*& layer);
55
56    /**
57     * Returns the layer of specified dimensions. If not suitable layer
58     * can be found, a new one is created and returned. If creating a new
59     * layer fails, NULL is returned.
60     *
61     * When a layer is obtained from the cache, it is removed and the total
62     * size of the cache goes down.
63     *
64     * @param size The dimensions of the desired layer
65     * @param previousFbo The name of the FBO to bind to if creating a new
66     *        layer fails
67     */
68    Layer* get(LayerSize& size, GLuint previousFbo);
69    /**
70     * Adds the layer to the cache. The layer will not be added if there is
71     * not enough space available.
72     *
73     * @param size The dimensions of the layer
74     * @param layer The layer to add to the cache
75     *
76     * @return True if the layer was added, false otherwise.
77     */
78    bool put(LayerSize& size, Layer* layer);
79    /**
80     * Clears the cache. This causes all layers to be deleted.
81     */
82    void clear();
83
84    /**
85     * Sets the maximum size of the cache in bytes.
86     */
87    void setMaxSize(uint32_t maxSize);
88    /**
89     * Returns the maximum size of the cache in bytes.
90     */
91    uint32_t getMaxSize();
92    /**
93     * Returns the current size of the cache in bytes.
94     */
95    uint32_t getSize();
96
97private:
98    void deleteLayer(Layer* layer);
99
100    GenerationCache<LayerSize, Layer*> mCache;
101    uint32_t mIdGenerator;
102
103    uint32_t mSize;
104    uint32_t mMaxSize;
105}; // class LayerCache
106
107}; // namespace uirenderer
108}; // namespace android
109
110#endif // ANDROID_UI_LAYER_CACHE_H
111