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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 
30 namespace android {
31 
32 class BufferQueue;
33 
34 /**
35  * BufferItemConsumer is a BufferQueue consumer endpoint that allows clients
36  * access to the whole BufferItem entry from BufferQueue. Multiple buffers may
37  * be acquired at once, to be used concurrently by the client. This consumer can
38  * operate either in synchronous or asynchronous mode.
39  */
40 class BufferItemConsumer: public ConsumerBase
41 {
42   public:
43     typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
44 
45     typedef BufferQueue::BufferItem BufferItem;
46 
47     enum { DEFAULT_MAX_BUFFERS = -1 };
48     enum { INVALID_BUFFER_SLOT = BufferQueue::INVALID_BUFFER_SLOT };
49     enum { NO_BUFFER_AVAILABLE = BufferQueue::NO_BUFFER_AVAILABLE };
50 
51     // Create a new buffer item consumer. The consumerUsage parameter determines
52     // the consumer usage flags passed to the graphics allocator. The
53     // bufferCount parameter specifies how many buffers can be locked for user
54     // access at the same time.
55     // controlledByApp tells whether this consumer is controlled by the
56     // application.
57     BufferItemConsumer(const sp<IGraphicBufferConsumer>& consumer,
58             uint32_t consumerUsage, int bufferCount = DEFAULT_MAX_BUFFERS,
59             bool controlledByApp = false);
60 
61     virtual ~BufferItemConsumer();
62 
63     // set the name of the BufferItemConsumer that will be used to identify it in
64     // log messages.
65     void setName(const String8& name);
66 
67     // Gets the next graphics buffer from the producer, filling out the
68     // passed-in BufferItem structure. Returns NO_BUFFER_AVAILABLE if the queue
69     // of buffers is empty, and INVALID_OPERATION if the maximum number of
70     // buffers is already acquired.
71     //
72     // Only a fixed number of buffers can be acquired at a time, determined by
73     // the construction-time bufferCount parameter. If INVALID_OPERATION is
74     // returned by acquireBuffer, then old buffers must be returned to the
75     // queue by calling releaseBuffer before more buffers can be acquired.
76     //
77     // If waitForFence is true, and the acquired BufferItem has a valid fence object,
78     // acquireBuffer will wait on the fence with no timeout before returning.
79     status_t acquireBuffer(BufferItem *item, nsecs_t presentWhen,
80         bool waitForFence = true);
81 
82     // Returns an acquired buffer to the queue, allowing it to be reused. Since
83     // only a fixed number of buffers may be acquired at a time, old buffers
84     // must be released by calling releaseBuffer to ensure new buffers can be
85     // acquired by acquireBuffer. Once a BufferItem is released, the caller must
86     // not access any members of the BufferItem, and should immediately remove
87     // all of its references to the BufferItem itself.
88     status_t releaseBuffer(const BufferItem &item,
89             const sp<Fence>& releaseFence = Fence::NO_FENCE);
90 
91     // setDefaultBufferSize is used to set the size of buffers returned by
92     // requestBuffers when a with and height of zero is requested.
93     status_t setDefaultBufferSize(uint32_t w, uint32_t h);
94 
95     // setDefaultBufferFormat allows the BufferQueue to create
96     // GraphicBuffers of a defaultFormat if no format is specified
97     // in dequeueBuffer
98     status_t setDefaultBufferFormat(uint32_t defaultFormat);
99 };
100 
101 } // namespace android
102 
103 #endif // ANDROID_GUI_CPUCONSUMER_H
104