CpuConsumer.h revision ae772278fe52335b730442f3d86307787dea807e 
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
29namespace android {
30
31/**
32 * CpuConsumer is a BufferQueue consumer endpoint that allows direct CPU
33 * access to the underlying gralloc buffers provided by BufferQueue. Multiple
34 * buffers may be acquired by it at once, to be used concurrently by the
35 * CpuConsumer owner. Sets gralloc usage flags to be software-read-only.
36 * This queue is synchronous by default.
37 */
38
39class CpuConsumer : public ConsumerBase
40{
41  public:
42    typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
43
44    struct LockedBuffer {
45        uint8_t    *data;
46        uint32_t    width;
47        uint32_t    height;
48        PixelFormat format;
49        uint32_t    stride;
50        Rect        crop;
51        uint32_t    transform;
52        uint32_t    scalingMode;
53        int64_t     timestamp;
54        uint64_t    frameNumber;
55        // Values below are only valid when using
56        // HAL_PIXEL_FORMAT_YCbCr_420_888, in which case LockedBuffer::data
57        // contains the Y channel, and stride is the Y channel stride. For other
58        // formats, these will all be 0.
59        uint8_t    *dataCb;
60        uint8_t    *dataCr;
61        uint32_t    chromaStride;
62        uint32_t    chromaStep;
63    };
64
65    // Create a new CPU consumer. The maxLockedBuffers parameter specifies
66    // how many buffers can be locked for user access at the same time.
67    CpuConsumer(uint32_t maxLockedBuffers, bool synchronousMode = true);
68
69    virtual ~CpuConsumer();
70
71    // set the name of the CpuConsumer that will be used to identify it in
72    // log messages.
73    void setName(const String8& name);
74
75    // Gets the next graphics buffer from the producer and locks it for CPU use,
76    // filling out the passed-in locked buffer structure with the native pointer
77    // and metadata. Returns BAD_VALUE if no new buffer is available, and
78    // INVALID_OPERATION if the maximum number of buffers is already locked.
79    //
80    // Only a fixed number of buffers can be locked at a time, determined by the
81    // construction-time maxLockedBuffers parameter. If INVALID_OPERATION is
82    // returned by lockNextBuffer, then old buffers must be returned to the queue
83    // by calling unlockBuffer before more buffers can be acquired.
84    status_t lockNextBuffer(LockedBuffer *nativeBuffer);
85
86    // Returns a locked buffer to the queue, allowing it to be reused. Since
87    // only a fixed number of buffers may be locked at a time, old buffers must
88    // be released by calling unlockBuffer to ensure new buffers can be acquired by
89    // lockNextBuffer.
90    status_t unlockBuffer(const LockedBuffer &nativeBuffer);
91
92    sp<IGraphicBufferProducer> getProducerInterface() const { return getBufferQueue(); }
93
94  private:
95    // Maximum number of buffers that can be locked at a time
96    uint32_t mMaxLockedBuffers;
97
98    status_t releaseAcquiredBufferLocked(int lockedIdx);
99
100    virtual void freeBufferLocked(int slotIndex);
101
102    // Tracking for buffers acquired by the user
103    struct AcquiredBuffer {
104        // Need to track the original mSlot index and the buffer itself because
105        // the mSlot entry may be freed/reused before the acquired buffer is
106        // released.
107        int mSlot;
108        sp<GraphicBuffer> mGraphicBuffer;
109        void *mBufferPointer;
110
111        AcquiredBuffer() :
112                mSlot(BufferQueue::INVALID_BUFFER_SLOT),
113                mBufferPointer(NULL) {
114        }
115    };
116    Vector<AcquiredBuffer> mAcquiredBuffers;
117
118    // Count of currently locked buffers
119    uint32_t mCurrentLockedBuffers;
120
121};
122
123} // namespace android
124
125#endif // ANDROID_GUI_CPUCONSUMER_H
126