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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_CPUCONSUMER_H
18 #define ANDROID_GUI_CPUCONSUMER_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 
29 namespace android {
30 
31 class BufferQueue;
32 
33 /**
34  * CpuConsumer is a BufferQueue consumer endpoint that allows direct CPU
35  * access to the underlying gralloc buffers provided by BufferQueue. Multiple
36  * buffers may be acquired by it at once, to be used concurrently by the
37  * CpuConsumer owner. Sets gralloc usage flags to be software-read-only.
38  * This queue is synchronous by default.
39  */
40 
41 class CpuConsumer : public ConsumerBase
42 {
43   public:
44     typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
45 
46     struct LockedBuffer {
47         uint8_t    *data;
48         uint32_t    width;
49         uint32_t    height;
50         PixelFormat format;
51         uint32_t    stride;
52         Rect        crop;
53         uint32_t    transform;
54         uint32_t    scalingMode;
55         int64_t     timestamp;
56         uint64_t    frameNumber;
57         // Values below are only valid when using
58         // HAL_PIXEL_FORMAT_YCbCr_420_888, in which case LockedBuffer::data
59         // contains the Y channel, and stride is the Y channel stride. For other
60         // formats, these will all be 0.
61         uint8_t    *dataCb;
62         uint8_t    *dataCr;
63         uint32_t    chromaStride;
64         uint32_t    chromaStep;
65     };
66 
67     // Create a new CPU consumer. The maxLockedBuffers parameter specifies
68     // how many buffers can be locked for user access at the same time.
69     CpuConsumer(const sp<IGraphicBufferConsumer>& bq,
70             uint32_t maxLockedBuffers, bool controlledByApp = false);
71 
72     virtual ~CpuConsumer();
73 
74     // set the name of the CpuConsumer that will be used to identify it in
75     // log messages.
76     void setName(const String8& name);
77 
78     // setDefaultBufferSize is used to set the size of buffers returned by
79     // requestBuffers when a width and height of zero is requested.
80     // A call to setDefaultBufferSize() may trigger requestBuffers() to
81     // be called from the client. Default size is 1x1.
82     status_t setDefaultBufferSize(uint32_t width, uint32_t height);
83 
84     // setDefaultBufferFormat allows CpuConsumer's BufferQueue to create buffers
85     // of a defaultFormat if no format is specified by producer. Formats are
86     // enumerated in graphics.h; the initial default is
87     // HAL_PIXEL_FORMAT_RGBA_8888.
88     status_t setDefaultBufferFormat(uint32_t defaultFormat);
89 
90     // Gets the next graphics buffer from the producer and locks it for CPU use,
91     // filling out the passed-in locked buffer structure with the native pointer
92     // and metadata. Returns BAD_VALUE if no new buffer is available, and
93     // NOT_ENOUGH_DATA if the maximum number of buffers is already locked.
94     //
95     // Only a fixed number of buffers can be locked at a time, determined by the
96     // construction-time maxLockedBuffers parameter. If INVALID_OPERATION is
97     // returned by lockNextBuffer, then old buffers must be returned to the queue
98     // by calling unlockBuffer before more buffers can be acquired.
99     status_t lockNextBuffer(LockedBuffer *nativeBuffer);
100 
101     // Returns a locked buffer to the queue, allowing it to be reused. Since
102     // only a fixed number of buffers may be locked at a time, old buffers must
103     // be released by calling unlockBuffer to ensure new buffers can be acquired by
104     // lockNextBuffer.
105     status_t unlockBuffer(const LockedBuffer &nativeBuffer);
106 
107   private:
108     // Maximum number of buffers that can be locked at a time
109     uint32_t mMaxLockedBuffers;
110 
111     status_t releaseAcquiredBufferLocked(int lockedIdx);
112 
113     virtual void freeBufferLocked(int slotIndex);
114 
115     // Tracking for buffers acquired by the user
116     struct AcquiredBuffer {
117         // Need to track the original mSlot index and the buffer itself because
118         // the mSlot entry may be freed/reused before the acquired buffer is
119         // released.
120         int mSlot;
121         sp<GraphicBuffer> mGraphicBuffer;
122         void *mBufferPointer;
123 
AcquiredBufferAcquiredBuffer124         AcquiredBuffer() :
125                 mSlot(BufferQueue::INVALID_BUFFER_SLOT),
126                 mBufferPointer(NULL) {
127         }
128     };
129     Vector<AcquiredBuffer> mAcquiredBuffers;
130 
131     // Count of currently locked buffers
132     uint32_t mCurrentLockedBuffers;
133 
134 };
135 
136 } // namespace android
137 
138 #endif // ANDROID_GUI_CPUCONSUMER_H
139