1/*
2 * Copyright 2014 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_BUFFERQUEUEPRODUCER_H
18#define ANDROID_GUI_BUFFERQUEUEPRODUCER_H
19
20#include <gui/BufferQueueDefs.h>
21#include <gui/IGraphicBufferProducer.h>
22
23namespace android {
24
25struct BufferSlot;
26
27class BufferQueueProducer : public BnGraphicBufferProducer,
28                            private IBinder::DeathRecipient {
29public:
30    friend class BufferQueue; // Needed to access binderDied
31
32    BufferQueueProducer(const sp<BufferQueueCore>& core, bool consumerIsSurfaceFlinger = false);
33    ~BufferQueueProducer() override;
34
35    // requestBuffer returns the GraphicBuffer for slot N.
36    //
37    // In normal operation, this is called the first time slot N is returned
38    // by dequeueBuffer.  It must be called again if dequeueBuffer returns
39    // flags indicating that previously-returned buffers are no longer valid.
40    virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf);
41
42    // see IGraphicsBufferProducer::setMaxDequeuedBufferCount
43    virtual status_t setMaxDequeuedBufferCount(int maxDequeuedBuffers);
44
45    // see IGraphicsBufferProducer::setAsyncMode
46    virtual status_t setAsyncMode(bool async);
47
48    // dequeueBuffer gets the next buffer slot index for the producer to use.
49    // If a buffer slot is available then that slot index is written to the
50    // location pointed to by the buf argument and a status of OK is returned.
51    // If no slot is available then a status of -EBUSY is returned and buf is
52    // unmodified.
53    //
54    // The outFence parameter will be updated to hold the fence associated with
55    // the buffer. The contents of the buffer must not be overwritten until the
56    // fence signals. If the fence is Fence::NO_FENCE, the buffer may be
57    // written immediately.
58    //
59    // The width and height parameters must be no greater than the minimum of
60    // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
61    // An error due to invalid dimensions might not be reported until
62    // updateTexImage() is called.  If width and height are both zero, the
63    // default values specified by setDefaultBufferSize() are used instead.
64    //
65    // If the format is 0, the default format will be used.
66    //
67    // The usage argument specifies gralloc buffer usage flags.  The values
68    // are enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER.  These
69    // will be merged with the usage flags specified by setConsumerUsageBits.
70    //
71    // The return value may be a negative error value or a non-negative
72    // collection of flags.  If the flags are set, the return values are
73    // valid, but additional actions must be performed.
74    //
75    // If IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION is set, the
76    // producer must discard cached GraphicBuffer references for the slot
77    // returned in buf.
78    // If IGraphicBufferProducer::RELEASE_ALL_BUFFERS is set, the producer
79    // must discard cached GraphicBuffer references for all slots.
80    //
81    // In both cases, the producer will need to call requestBuffer to get a
82    // GraphicBuffer handle for the returned slot.
83    virtual status_t dequeueBuffer(int* outSlot, sp<Fence>* outFence, uint32_t width,
84                                   uint32_t height, PixelFormat format, uint64_t usage,
85                                   uint64_t* outBufferAge,
86                                   FrameEventHistoryDelta* outTimestamps) override;
87
88    // See IGraphicBufferProducer::detachBuffer
89    virtual status_t detachBuffer(int slot);
90
91    // See IGraphicBufferProducer::detachNextBuffer
92    virtual status_t detachNextBuffer(sp<GraphicBuffer>* outBuffer,
93            sp<Fence>* outFence);
94
95    // See IGraphicBufferProducer::attachBuffer
96    virtual status_t attachBuffer(int* outSlot, const sp<GraphicBuffer>& buffer);
97
98    // queueBuffer returns a filled buffer to the BufferQueue.
99    //
100    // Additional data is provided in the QueueBufferInput struct.  Notably,
101    // a timestamp must be provided for the buffer. The timestamp is in
102    // nanoseconds, and must be monotonically increasing. Its other semantics
103    // (zero point, etc) are producer-specific and should be documented by the
104    // producer.
105    //
106    // The caller may provide a fence that signals when all rendering
107    // operations have completed.  Alternatively, NO_FENCE may be used,
108    // indicating that the buffer is ready immediately.
109    //
110    // Some values are returned in the output struct: the current settings
111    // for default width and height, the current transform hint, and the
112    // number of queued buffers.
113    virtual status_t queueBuffer(int slot,
114            const QueueBufferInput& input, QueueBufferOutput* output);
115
116    // cancelBuffer returns a dequeued buffer to the BufferQueue, but doesn't
117    // queue it for use by the consumer.
118    //
119    // The buffer will not be overwritten until the fence signals.  The fence
120    // will usually be the one obtained from dequeueBuffer.
121    virtual status_t cancelBuffer(int slot, const sp<Fence>& fence);
122
123    // Query native window attributes.  The "what" values are enumerated in
124    // window.h (e.g. NATIVE_WINDOW_FORMAT).
125    virtual int query(int what, int* outValue);
126
127    // connect attempts to connect a producer API to the BufferQueue.  This
128    // must be called before any other IGraphicBufferProducer methods are
129    // called except for getAllocator.  A consumer must already be connected.
130    //
131    // This method will fail if connect was previously called on the
132    // BufferQueue and no corresponding disconnect call was made (i.e. if
133    // it's still connected to a producer).
134    //
135    // APIs are enumerated in window.h (e.g. NATIVE_WINDOW_API_CPU).
136    virtual status_t connect(const sp<IProducerListener>& listener,
137            int api, bool producerControlledByApp, QueueBufferOutput* output);
138
139    // See IGraphicBufferProducer::disconnect
140    virtual status_t disconnect(int api, DisconnectMode mode = DisconnectMode::Api);
141
142    // Attaches a sideband buffer stream to the IGraphicBufferProducer.
143    //
144    // A sideband stream is a device-specific mechanism for passing buffers
145    // from the producer to the consumer without using dequeueBuffer/
146    // queueBuffer. If a sideband stream is present, the consumer can choose
147    // whether to acquire buffers from the sideband stream or from the queued
148    // buffers.
149    //
150    // Passing NULL or a different stream handle will detach the previous
151    // handle if any.
152    virtual status_t setSidebandStream(const sp<NativeHandle>& stream);
153
154    // See IGraphicBufferProducer::allocateBuffers
155    virtual void allocateBuffers(uint32_t width, uint32_t height,
156            PixelFormat format, uint64_t usage) override;
157
158    // See IGraphicBufferProducer::allowAllocation
159    virtual status_t allowAllocation(bool allow);
160
161    // See IGraphicBufferProducer::setGenerationNumber
162    virtual status_t setGenerationNumber(uint32_t generationNumber);
163
164    // See IGraphicBufferProducer::getConsumerName
165    virtual String8 getConsumerName() const override;
166
167    // See IGraphicBufferProducer::setSharedBufferMode
168    virtual status_t setSharedBufferMode(bool sharedBufferMode) override;
169
170    // See IGraphicBufferProducer::setAutoRefresh
171    virtual status_t setAutoRefresh(bool autoRefresh) override;
172
173    // See IGraphicBufferProducer::setDequeueTimeout
174    virtual status_t setDequeueTimeout(nsecs_t timeout) override;
175
176    // See IGraphicBufferProducer::getLastQueuedBuffer
177    virtual status_t getLastQueuedBuffer(sp<GraphicBuffer>* outBuffer,
178            sp<Fence>* outFence, float outTransformMatrix[16]) override;
179
180    // See IGraphicBufferProducer::getFrameTimestamps
181    virtual void getFrameTimestamps(FrameEventHistoryDelta* outDelta) override;
182
183    // See IGraphicBufferProducer::getUniqueId
184    virtual status_t getUniqueId(uint64_t* outId) const override;
185
186    // See IGraphicBufferProducer::getConsumerUsage
187    virtual status_t getConsumerUsage(uint64_t* outUsage) const override;
188
189private:
190    // This is required by the IBinder::DeathRecipient interface
191    virtual void binderDied(const wp<IBinder>& who);
192
193    // Returns the slot of the next free buffer if one is available or
194    // BufferQueueCore::INVALID_BUFFER_SLOT otherwise
195    int getFreeBufferLocked() const;
196
197    // Returns the next free slot if one is available or
198    // BufferQueueCore::INVALID_BUFFER_SLOT otherwise
199    int getFreeSlotLocked() const;
200
201    void addAndGetFrameTimestamps(const NewFrameEventsEntry* newTimestamps,
202            FrameEventHistoryDelta* outDelta);
203
204    // waitForFreeSlotThenRelock finds the oldest slot in the FREE state. It may
205    // block if there are no available slots and we are not in non-blocking
206    // mode (producer and consumer controlled by the application). If it blocks,
207    // it will release mCore->mMutex while blocked so that other operations on
208    // the BufferQueue may succeed.
209    enum class FreeSlotCaller {
210        Dequeue,
211        Attach,
212    };
213    status_t waitForFreeSlotThenRelock(FreeSlotCaller caller, int* found) const;
214
215    sp<BufferQueueCore> mCore;
216
217    // This references mCore->mSlots. Lock mCore->mMutex while accessing.
218    BufferQueueDefs::SlotsType& mSlots;
219
220    // This is a cached copy of the name stored in the BufferQueueCore.
221    // It's updated during connect and dequeueBuffer (which should catch
222    // most updates).
223    String8 mConsumerName;
224
225    uint32_t mStickyTransform;
226
227    // This controls whether the GraphicBuffer pointer in the BufferItem is
228    // cleared after being queued
229    bool mConsumerIsSurfaceFlinger;
230
231    // This saves the fence from the last queueBuffer, such that the
232    // next queueBuffer call can throttle buffer production. The prior
233    // queueBuffer's fence is not nessessarily available elsewhere,
234    // since the previous buffer might have already been acquired.
235    sp<Fence> mLastQueueBufferFence;
236
237    Rect mLastQueuedCrop;
238    uint32_t mLastQueuedTransform;
239
240    // Take-a-ticket system for ensuring that onFrame* callbacks are called in
241    // the order that frames are queued. While the BufferQueue lock
242    // (mCore->mMutex) is held, a ticket is retained by the producer. After
243    // dropping the BufferQueue lock, the producer must wait on the condition
244    // variable until the current callback ticket matches its retained ticket.
245    Mutex mCallbackMutex;
246    int mNextCallbackTicket; // Protected by mCore->mMutex
247    int mCurrentCallbackTicket; // Protected by mCallbackMutex
248    Condition mCallbackCondition;
249
250    // Sets how long dequeueBuffer or attachBuffer will block if a buffer or
251    // slot is not yet available.
252    nsecs_t mDequeueTimeout;
253
254}; // class BufferQueueProducer
255
256} // namespace android
257
258#endif
259