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#include <gui/BufferQueue.h>
22
23#define ANDROID_GRAPHICS_BUFFERITEMCONSUMER_JNI_ID "mBufferItemConsumer"
24
25namespace android {
26
27class String8;
28
29/**
30 * BufferItemConsumer is a BufferQueue consumer endpoint that allows clients
31 * access to the whole BufferItem entry from BufferQueue. Multiple buffers may
32 * be acquired at once, to be used concurrently by the client. This consumer can
33 * operate either in synchronous or asynchronous mode.
34 */
35class BufferItemConsumer: public ConsumerBase
36{
37  public:
38    typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
39
40    struct BufferFreedListener : public virtual RefBase {
41        virtual void onBufferFreed(const wp<GraphicBuffer>& graphicBuffer) = 0;
42    };
43
44    enum { DEFAULT_MAX_BUFFERS = -1 };
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    // controlledByApp tells whether this consumer is controlled by the
53    // application.
54    BufferItemConsumer(const sp<IGraphicBufferConsumer>& consumer,
55            uint32_t consumerUsage, int bufferCount = DEFAULT_MAX_BUFFERS,
56            bool controlledByApp = false);
57
58    virtual ~BufferItemConsumer();
59
60    // set the name of the BufferItemConsumer that will be used to identify it in
61    // log messages.
62    void setName(const String8& name);
63
64    // setBufferFreedListener sets the listener object that will be notified
65    // when an old buffer is being freed.
66    void setBufferFreedListener(const wp<BufferFreedListener>& listener);
67
68    // Gets the next graphics buffer from the producer, filling out the
69    // passed-in BufferItem structure. Returns NO_BUFFER_AVAILABLE if the queue
70    // of buffers is empty, and INVALID_OPERATION if the maximum number of
71    // buffers is already acquired.
72    //
73    // Only a fixed number of buffers can be acquired at a time, determined by
74    // the construction-time bufferCount parameter. If INVALID_OPERATION is
75    // returned by acquireBuffer, then old buffers must be returned to the
76    // queue by calling releaseBuffer before more buffers can be acquired.
77    //
78    // If waitForFence is true, and the acquired BufferItem has a valid fence object,
79    // acquireBuffer will wait on the fence with no timeout before returning.
80    status_t acquireBuffer(BufferItem* item, nsecs_t presentWhen,
81            bool waitForFence = true);
82
83    // Returns an acquired buffer to the queue, allowing it to be reused. Since
84    // only a fixed number of buffers may be acquired at a time, old buffers
85    // must be released by calling releaseBuffer to ensure new buffers can be
86    // acquired by acquireBuffer. Once a BufferItem is released, the caller must
87    // not access any members of the BufferItem, and should immediately remove
88    // all of its references to the BufferItem itself.
89    status_t releaseBuffer(const BufferItem &item,
90            const sp<Fence>& releaseFence = Fence::NO_FENCE);
91
92   private:
93    void freeBufferLocked(int slotIndex) override;
94
95    // mBufferFreedListener is the listener object that will be called when
96    // an old buffer is being freed. If it is not NULL it will be called from
97    // freeBufferLocked.
98    wp<BufferFreedListener> mBufferFreedListener;
99};
100
101} // namespace android
102
103#endif // ANDROID_GUI_CPUCONSUMER_H
104