LayerCache.h revision 5baa3a62a97544669fba6d65a11c07f252e654dd 
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_HWUI_LAYER_CACHE_H
18#define ANDROID_HWUI_LAYER_CACHE_H
19
20#include "Debug.h"
21#include "Layer.h"
22#include "Properties.h"
23#include "utils/SortedList.h"
24
25namespace android {
26namespace uirenderer {
27
28///////////////////////////////////////////////////////////////////////////////
29// Defines
30///////////////////////////////////////////////////////////////////////////////
31
32// Debug
33#if DEBUG_LAYERS
34    #define LAYER_LOGD(...) ALOGD(__VA_ARGS__)
35#else
36    #define LAYER_LOGD(...)
37#endif
38
39///////////////////////////////////////////////////////////////////////////////
40// Cache
41///////////////////////////////////////////////////////////////////////////////
42
43class LayerCache {
44public:
45    LayerCache();
46    ~LayerCache();
47
48    /**
49     * Returns a layer large enough for the specified dimensions. If no suitable
50     * layer can be found, a new one is created and returned. If creating a new
51     * layer fails, NULL is returned.
52     *
53     * When a layer is obtained from the cache, it is removed and the total
54     * size of the cache goes down.
55     *
56     * @param width The desired width of the layer
57     * @param width The desired height of the layer
58     */
59    Layer* get(const uint32_t width, const uint32_t height);
60
61    /**
62     * Adds the layer to the cache. The layer will not be added if there is
63     * not enough space available. Adding a layer can cause other layers to
64     * be removed from the cache.
65     *
66     * @param layer The layer to add to the cache
67     *
68     * @return True if the layer was added, false otherwise.
69     */
70    bool put(Layer* layer);
71    /**
72     * Clears the cache. This causes all layers to be deleted.
73     */
74    void clear();
75    /**
76     * Resize the specified layer if needed.
77     *
78     * @param layer The layer to resize
79     * @param width The new width of the layer
80     * @param height The new height of the layer
81     *
82     * @return True if the layer was resized or nothing happened, false if
83     *         a failure occurred during the resizing operation
84     */
85    bool resize(Layer* layer, const uint32_t width, const uint32_t height);
86
87    /**
88     * Sets the maximum size of the cache in bytes.
89     */
90    void setMaxSize(uint32_t maxSize);
91    /**
92     * Returns the maximum size of the cache in bytes.
93     */
94    uint32_t getMaxSize();
95    /**
96     * Returns the current size of the cache in bytes.
97     */
98    uint32_t getSize();
99
100    /**
101     * Prints out the content of the cache.
102     */
103    void dump();
104
105private:
106    void deleteLayer(Layer* layer);
107
108    struct LayerEntry {
109        LayerEntry():
110            mLayer(NULL), mWidth(0), mHeight(0) {
111        }
112
113        LayerEntry(const uint32_t layerWidth, const uint32_t layerHeight): mLayer(NULL) {
114            mWidth = uint32_t(ceilf(layerWidth / float(LAYER_SIZE)) * LAYER_SIZE);
115            mHeight = uint32_t(ceilf(layerHeight / float(LAYER_SIZE)) * LAYER_SIZE);
116        }
117
118        LayerEntry(Layer* layer):
119            mLayer(layer), mWidth(layer->getWidth()), mHeight(layer->getHeight()) {
120        }
121
122        bool operator<(const LayerEntry& rhs) const {
123            if (mWidth == rhs.mWidth) {
124                return mHeight < rhs.mHeight;
125            }
126            return mWidth < rhs.mWidth;
127        }
128
129        bool operator==(const LayerEntry& rhs) const {
130            return mWidth == rhs.mWidth && mHeight == rhs.mHeight;
131        }
132
133        Layer* mLayer;
134        uint32_t mWidth;
135        uint32_t mHeight;
136    }; // struct LayerEntry
137
138    SortedList<LayerEntry> mCache;
139
140    uint32_t mSize;
141    uint32_t mMaxSize;
142}; // class LayerCache
143
144}; // namespace uirenderer
145}; // namespace android
146
147#endif // ANDROID_HWUI_LAYER_CACHE_H
148