CpuConsumer.h revision f57e7540d4cf799f18fe87d3536c55f1e0064931
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#define ANDROID_GRAPHICS_CPUCONSUMER_JNI_ID "mCpuConsumer"
29
30namespace android {
31
32/**
33 * CpuConsumer is a BufferQueue consumer endpoint that allows direct CPU
34 * access to the underlying gralloc buffers provided by BufferQueue. Multiple
35 * buffers may be acquired by it at once, to be used concurrently by the
36 * CpuConsumer owner. Sets gralloc usage flags to be software-read-only.
37 * This queue is synchronous by default.
38 */
39
40class CpuConsumer: public ConsumerBase
41{
42  public:
43    typedef ConsumerBase::FrameAvailableListener FrameAvailableListener;
44
45    struct LockedBuffer {
46        uint8_t    *data;
47        uint32_t    width;
48        uint32_t    height;
49        PixelFormat format;
50        uint32_t    stride;
51        Rect        crop;
52        uint32_t    transform;
53        uint32_t    scalingMode;
54        int64_t     timestamp;
55        uint64_t    frameNumber;
56    };
57
58    // Create a new CPU consumer. The maxLockedBuffers parameter specifies
59    // how many buffers can be locked for user access at the same time.
60    CpuConsumer(uint32_t maxLockedBuffers);
61
62    // set the name of the CpuConsumer that will be used to identify it in
63    // log messages.
64    void setName(const String8& name);
65
66    // Gets the next graphics buffer from the producer and locks it for CPU use,
67    // filling out the passed-in locked buffer structure with the native pointer
68    // and metadata. Returns BAD_VALUE if no new buffer is available, and
69    // INVALID_OPERATION if the maximum number of buffers is already locked.
70    //
71    // Only a fixed number of buffers can be locked at a time, determined by the
72    // construction-time maxLockedBuffers parameter. If INVALID_OPERATION is
73    // returned by lockNextBuffer, then old buffers must be returned to the queue
74    // by calling unlockBuffer before more buffers can be acquired.
75    status_t lockNextBuffer(LockedBuffer *nativeBuffer);
76
77    // Returns a locked buffer to the queue, allowing it to be reused. Since
78    // only a fixed number of buffers may be locked at a time, old buffers must
79    // be released by calling unlockBuffer to ensure new buffers can be acquired by
80    // lockNextBuffer.
81    status_t unlockBuffer(const LockedBuffer &nativeBuffer);
82
83    sp<ISurfaceTexture> getProducerInterface() const { return getBufferQueue(); }
84
85  private:
86    // Maximum number of buffers that can be locked at a time
87    uint32_t mMaxLockedBuffers;
88
89    void freeBufferLocked(int slotIndex);
90
91    // Array for tracking pointers passed to the consumer, matching the
92    // mSlots indexing
93    void *mBufferPointers[BufferQueue::NUM_BUFFER_SLOTS];
94    // Count of currently locked buffers
95    uint32_t mCurrentLockedBuffers;
96
97};
98
99} // namespace android
100
101#endif // ANDROID_GUI_CPUCONSUMER_H
102