LayerCache.h revision eb99356a0548684a501766e6a524529ab93304c8 
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     */
66    Layer* get(LayerSize& size);
67
68    /**
69     * Adds the layer to the cache. The layer will not be added if there is
70     * not enough space available.
71     *
72     * @param size The dimensions of the layer
73     * @param layer The layer to add to the cache
74     *
75     * @return True if the layer was added, false otherwise.
76     */
77    bool put(LayerSize& size, Layer* layer);
78    /**
79     * Clears the cache. This causes all layers to be deleted.
80     */
81    void clear();
82
83    /**
84     * Sets the maximum size of the cache in bytes.
85     */
86    void setMaxSize(uint32_t maxSize);
87    /**
88     * Returns the maximum size of the cache in bytes.
89     */
90    uint32_t getMaxSize();
91    /**
92     * Returns the current size of the cache in bytes.
93     */
94    uint32_t getSize();
95
96private:
97    void deleteLayer(Layer* layer);
98
99    GenerationCache<LayerSize, Layer*> mCache;
100
101    uint32_t mSize;
102    uint32_t mMaxSize;
103}; // class LayerCache
104
105}; // namespace uirenderer
106}; // namespace android
107
108#endif // ANDROID_UI_LAYER_CACHE_H
109