CpuConsumer.h revision a5b7513711555c8681eb9391cfafe30fb7d6dd3d 
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
31class 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
41class 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
124        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