LayerCache.h revision 8d4aeb7111afac0c3c7e56d4ad5d92f9cfce2ffd 
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 "utils/SortedList.h"
23
24namespace android {
25namespace uirenderer {
26
27///////////////////////////////////////////////////////////////////////////////
28// Defines
29///////////////////////////////////////////////////////////////////////////////
30
31// Debug
32#if DEBUG_LAYERS
33    #define LAYER_LOGD(...) ALOGD(__VA_ARGS__)
34#else
35    #define LAYER_LOGD(...)
36#endif
37
38///////////////////////////////////////////////////////////////////////////////
39// Cache
40///////////////////////////////////////////////////////////////////////////////
41
42class LayerCache {
43public:
44    LayerCache();
45    ~LayerCache();
46
47    /**
48     * Returns a layer large enough for the specified dimensions. If no suitable
49     * layer can be found, a new one is created and returned. If creating a new
50     * layer fails, NULL is returned.
51     *
52     * When a layer is obtained from the cache, it is removed and the total
53     * size of the cache goes down.
54     *
55     * @param width The desired width of the layer
56     * @param height The desired height of the layer
57     */
58    Layer* get(const uint32_t width, const uint32_t height);
59
60    /**
61     * Adds the layer to the cache. The layer will not be added if there is
62     * not enough space available. Adding a layer can cause other layers to
63     * be removed from the cache.
64     *
65     * @param layer The layer to add to the cache
66     *
67     * @return True if the layer was added, false otherwise.
68     */
69    bool put(Layer* layer);
70    /**
71     * Clears the cache. This causes all layers to be deleted.
72     */
73    void clear();
74
75    /**
76     * Sets the maximum size of the cache in bytes.
77     */
78    void setMaxSize(uint32_t maxSize);
79    /**
80     * Returns the maximum size of the cache in bytes.
81     */
82    uint32_t getMaxSize();
83    /**
84     * Returns the current size of the cache in bytes.
85     */
86    uint32_t getSize();
87
88    /**
89     * Prints out the content of the cache.
90     */
91    void dump();
92
93private:
94    struct LayerEntry {
95        LayerEntry():
96            mLayer(NULL), mWidth(0), mHeight(0) {
97        }
98
99        LayerEntry(const uint32_t layerWidth, const uint32_t layerHeight): mLayer(NULL) {
100            mWidth = Layer::computeIdealWidth(layerWidth);
101            mHeight = Layer::computeIdealHeight(layerHeight);
102        }
103
104        LayerEntry(Layer* layer):
105            mLayer(layer), mWidth(layer->getWidth()), mHeight(layer->getHeight()) {
106        }
107
108        static int compare(const LayerEntry& lhs, const LayerEntry& rhs);
109
110        bool operator==(const LayerEntry& other) const {
111            return compare(*this, other) == 0;
112        }
113
114        bool operator!=(const LayerEntry& other) const {
115            return compare(*this, other) != 0;
116        }
117
118        friend inline int strictly_order_type(const LayerEntry& lhs, const LayerEntry& rhs) {
119            return LayerEntry::compare(lhs, rhs) < 0;
120        }
121
122        friend inline int compare_type(const LayerEntry& lhs, const LayerEntry& rhs) {
123            return LayerEntry::compare(lhs, rhs);
124        }
125
126        Layer* mLayer;
127        uint32_t mWidth;
128        uint32_t mHeight;
129    }; // struct LayerEntry
130
131    void deleteLayer(Layer* layer);
132
133    SortedList<LayerEntry> mCache;
134
135    uint32_t mSize;
136    uint32_t mMaxSize;
137}; // class LayerCache
138
139}; // namespace uirenderer
140}; // namespace android
141
142#endif // ANDROID_HWUI_LAYER_CACHE_H
143