BufferItemConsumer.h revision 1585c4d9fbbba3ba70ae625923b85cd02cb8a0fd 
1/*
2 * Copyright (C) 2012 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_GUI_BUFFERITEMCONSUMER_H
18#define ANDROID_GUI_BUFFERITEMCONSUMER_H
19
20#include <gui/ConsumerBase.h>
21
22#include <ui/GraphicBuffer.h>
23
24#include <utils/String8.h>
25#include <utils/Vector.h>
26#include <utils/threads.h>
27
28#define ANDROID_GRAPHICS_BUFFERITEMCONSUMER_JNI_ID "mBufferItemConsumer"
29
30namespace android {
31
32/**
33 * BufferItemConsumer is a BufferQueue consumer endpoint that allows clients
34 * access to the whole BufferItem entry from BufferQueue. Multiple buffers may
35 * be acquired at once, to be used concurrently by the client. This consumer can
36 * operate either in synchronous or asynchronous mode.
37 */
38class BufferItemConsumer: public ConsumerBase
39{
40  public:
41    typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
42
43    typedef BufferQueue::BufferItem BufferItem;
44
45    enum { INVALID_BUFFER_SLOT = BufferQueue::INVALID_BUFFER_SLOT };
46    enum { NO_BUFFER_AVAILABLE = BufferQueue::NO_BUFFER_AVAILABLE };
47
48    // Create a new buffer item consumer. The consumerUsage parameter determines
49    // the consumer usage flags passed to the graphics allocator. The
50    // bufferCount parameter specifies how many buffers can be locked for user
51    // access at the same time.
52    BufferItemConsumer(uint32_t consumerUsage,
53            int bufferCount = BufferQueue::MIN_UNDEQUEUED_BUFFERS,
54            bool synchronousMode = false);
55
56    virtual ~BufferItemConsumer();
57
58    // set the name of the BufferItemConsumer that will be used to identify it in
59    // log messages.
60    void setName(const String8& name);
61
62    // Gets the next graphics buffer from the producer, filling out the
63    // passed-in BufferItem structure. Returns NO_BUFFER_AVAILABLE if the queue
64    // of buffers is empty, and INVALID_OPERATION if the maximum number of
65    // buffers is already acquired.
66    //
67    // Only a fixed number of buffers can be acquired at a time, determined by
68    // the construction-time bufferCount parameter. If INVALID_OPERATION is
69    // returned by acquireBuffer, then old buffers must be returned to the
70    // queue by calling releaseBuffer before more buffers can be acquired.
71    //
72    // If waitForFence is true, and the acquired BufferItem has a valid fence object,
73    // acquireBuffer will wait on the fence with no timeout before returning.
74    status_t acquireBuffer(BufferItem *item, nsecs_t presentWhen,
75        bool waitForFence = true);
76
77    // Returns an acquired buffer to the queue, allowing it to be reused. Since
78    // only a fixed number of buffers may be acquired at a time, old buffers
79    // must be released by calling releaseBuffer to ensure new buffers can be
80    // acquired by acquireBuffer. Once a BufferItem is released, the caller must
81    // not access any members of the BufferItem, and should immediately remove
82    // all of its references to the BufferItem itself.
83    status_t releaseBuffer(const BufferItem &item,
84            const sp<Fence>& releaseFence = Fence::NO_FENCE);
85
86    sp<IGraphicBufferProducer> getProducerInterface() const { return getBufferQueue(); }
87
88    // setDefaultBufferSize is used to set the size of buffers returned by
89    // requestBuffers when a with and height of zero is requested.
90    status_t setDefaultBufferSize(uint32_t w, uint32_t h);
91
92    // setDefaultBufferFormat allows the BufferQueue to create
93    // GraphicBuffers of a defaultFormat if no format is specified
94    // in dequeueBuffer
95    status_t setDefaultBufferFormat(uint32_t defaultFormat);
96};
97
98} // namespace android
99
100#endif // ANDROID_GUI_CPUCONSUMER_H
101