1/*
2 * Copyright (C) 2013 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_RENDER_BUFFER_CACHE_H
18#define ANDROID_HWUI_RENDER_BUFFER_CACHE_H
19
20#include <GLES2/gl2.h>
21
22#include "RenderBuffer.h"
23#include "utils/SortedList.h"
24
25namespace android {
26namespace uirenderer {
27
28class RenderBufferCache {
29public:
30    RenderBufferCache();
31    ~RenderBufferCache();
32
33    /**
34     * Returns a buffer with the exact specified dimensions. If no suitable
35     * buffer can be found, a new one is created and returned. If creating a
36     * new buffer fails, NULL is returned.
37     *
38     * When a buffer is obtained from the cache, it is removed and the total
39     * size of the cache goes down.
40     *
41     * The returned buffer is always allocated and bound
42     * (see RenderBuffer::isAllocated()).
43     *
44     * @param format The desired render buffer format
45     * @param width The desired width of the buffer
46     * @param height The desired height of the buffer
47     */
48    RenderBuffer* get(GLenum format, const uint32_t width, const uint32_t height);
49
50    /**
51     * Adds the buffer to the cache. The buffer will not be added if there is
52     * not enough space available. Adding a buffer can cause other buffer to
53     * be removed from the cache.
54     *
55     * @param buffer The render buffer to add to the cache
56     *
57     * @return True if the buffer was added, false otherwise.
58     */
59    bool put(RenderBuffer* buffer);
60    /**
61     * Clears the cache. This causes all layers to be deleted.
62     */
63    void clear();
64
65    /**
66     * Sets the maximum size of the cache in bytes.
67     */
68    void setMaxSize(uint32_t maxSize);
69    /**
70     * Returns the maximum size of the cache in bytes.
71     */
72    uint32_t getMaxSize();
73    /**
74     * Returns the current size of the cache in bytes.
75     */
76    uint32_t getSize();
77
78private:
79    struct RenderBufferEntry {
80        RenderBufferEntry():
81            mBuffer(NULL), mWidth(0), mHeight(0) {
82        }
83
84        RenderBufferEntry(GLenum format, const uint32_t width, const uint32_t height):
85            mBuffer(NULL), mFormat(format), mWidth(width), mHeight(height) {
86        }
87
88        RenderBufferEntry(RenderBuffer* buffer):
89            mBuffer(buffer), mFormat(buffer->getFormat()),
90            mWidth(buffer->getWidth()), mHeight(buffer->getHeight()) {
91        }
92
93        static int compare(const RenderBufferEntry& lhs, const RenderBufferEntry& rhs);
94
95        bool operator==(const RenderBufferEntry& other) const {
96            return compare(*this, other) == 0;
97        }
98
99        bool operator!=(const RenderBufferEntry& other) const {
100            return compare(*this, other) != 0;
101        }
102
103        friend inline int strictly_order_type(const RenderBufferEntry& lhs,
104                const RenderBufferEntry& rhs) {
105            return RenderBufferEntry::compare(lhs, rhs) < 0;
106        }
107
108        friend inline int compare_type(const RenderBufferEntry& lhs,
109                const RenderBufferEntry& rhs) {
110            return RenderBufferEntry::compare(lhs, rhs);
111        }
112
113        RenderBuffer* mBuffer;
114        GLenum mFormat;
115        uint32_t mWidth;
116        uint32_t mHeight;
117    }; // struct RenderBufferEntry
118
119    void deleteBuffer(RenderBuffer* buffer);
120
121    SortedList<RenderBufferEntry> mCache;
122
123    uint32_t mSize;
124    uint32_t mMaxSize;
125}; // class RenderBufferCache
126
127}; // namespace uirenderer
128}; // namespace android
129
130#endif // ANDROID_HWUI_RENDER_BUFFER_CACHE_H
131