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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/AdditionalOptions.h>
21 #include <gui/BufferQueueDefs.h>
22 
23 #include <gui/IGraphicBufferProducer.h>
24 
25 namespace android {
26 
27 class IBinder;
28 struct BufferSlot;
29 
30 #ifndef NO_BINDER
31 class BufferQueueProducer : public BnGraphicBufferProducer,
32                             private IBinder::DeathRecipient {
33 #else
34 class BufferQueueProducer : public BnGraphicBufferProducer {
35 #endif
36 public:
37     friend class BufferQueue; // Needed to access binderDied
38 
39     ~BufferQueueProducer() override;
40 
41     // requestBuffer returns the GraphicBuffer for slot N.
42     //
43     // In normal operation, this is called the first time slot N is returned
44     // by dequeueBuffer.  It must be called again if dequeueBuffer returns
45     // flags indicating that previously-returned buffers are no longer valid.
46     virtual status_t requestBuffer(int slot, sp<GraphicBuffer>* buf);
47 
48 #if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(WB_UNLIMITED_SLOTS)
49     // see IGraphicsBufferProducer::extendSlotCount
50     virtual status_t extendSlotCount(int size) override;
51 #endif
52 
53     // see IGraphicsBufferProducer::setMaxDequeuedBufferCount
54     virtual status_t setMaxDequeuedBufferCount(int maxDequeuedBuffers);
55 
56     // see IGraphicsBufferProducer::setAsyncMode
57     virtual status_t setAsyncMode(bool async);
58 
59     // dequeueBuffer gets the next buffer slot index for the producer to use.
60     // If a buffer slot is available then that slot index is written to the
61     // location pointed to by the buf argument and a status of OK is returned.
62     // If no slot is available then a status of -EBUSY is returned and buf is
63     // unmodified.
64     //
65     // The outFence parameter will be updated to hold the fence associated with
66     // the buffer. The contents of the buffer must not be overwritten until the
67     // fence signals. If the fence is Fence::NO_FENCE, the buffer may be
68     // written immediately.
69     //
70     // The width and height parameters must be no greater than the minimum of
71     // GL_MAX_VIEWPORT_DIMS and GL_MAX_TEXTURE_SIZE (see: glGetIntegerv).
72     // An error due to invalid dimensions might not be reported until
73     // updateTexImage() is called.  If width and height are both zero, the
74     // default values specified by setDefaultBufferSize() are used instead.
75     //
76     // If the format is 0, the default format will be used.
77     //
78     // The usage argument specifies gralloc buffer usage flags.  The values
79     // are enumerated in gralloc.h, e.g. GRALLOC_USAGE_HW_RENDER.  These
80     // will be merged with the usage flags specified by setConsumerUsageBits.
81     //
82     // The return value may be a negative error value or a non-negative
83     // collection of flags.  If the flags are set, the return values are
84     // valid, but additional actions must be performed.
85     //
86     // If IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION is set, the
87     // producer must discard cached GraphicBuffer references for the slot
88     // returned in buf.
89     // If IGraphicBufferProducer::RELEASE_ALL_BUFFERS is set, the producer
90     // must discard cached GraphicBuffer references for all slots.
91     //
92     // In both cases, the producer will need to call requestBuffer to get a
93     // GraphicBuffer handle for the returned slot.
94     virtual status_t dequeueBuffer(int* outSlot, sp<Fence>* outFence, uint32_t width,
95                                    uint32_t height, PixelFormat format, uint64_t usage,
96                                    uint64_t* outBufferAge,
97                                    FrameEventHistoryDelta* outTimestamps) override;
98 
99     // See IGraphicBufferProducer::detachBuffer
100     virtual status_t detachBuffer(int slot);
101 
102     // See IGraphicBufferProducer::detachNextBuffer
103     virtual status_t detachNextBuffer(sp<GraphicBuffer>* outBuffer,
104             sp<Fence>* outFence);
105 
106     // See IGraphicBufferProducer::attachBuffer
107     virtual status_t attachBuffer(int* outSlot, const sp<GraphicBuffer>& buffer);
108 
109     // queueBuffer returns a filled buffer to the BufferQueue.
110     //
111     // Additional data is provided in the QueueBufferInput struct.  Notably,
112     // a timestamp must be provided for the buffer. The timestamp is in
113     // nanoseconds, and must be monotonically increasing. Its other semantics
114     // (zero point, etc) are producer-specific and should be documented by the
115     // producer.
116     //
117     // The caller may provide a fence that signals when all rendering
118     // operations have completed.  Alternatively, NO_FENCE may be used,
119     // indicating that the buffer is ready immediately.
120     //
121     // Some values are returned in the output struct: the current settings
122     // for default width and height, the current transform hint, and the
123     // number of queued buffers.
124     virtual status_t queueBuffer(int slot,
125             const QueueBufferInput& input, QueueBufferOutput* output);
126 
127     // cancelBuffer returns a dequeued buffer to the BufferQueue, but doesn't
128     // queue it for use by the consumer.
129     //
130     // The buffer will not be overwritten until the fence signals.  The fence
131     // will usually be the one obtained from dequeueBuffer.
132     virtual status_t cancelBuffer(int slot, const sp<Fence>& fence);
133 
134     // Query native window attributes.  The "what" values are enumerated in
135     // window.h (e.g. NATIVE_WINDOW_FORMAT).
136     virtual int query(int what, int* outValue);
137 
138     // connect attempts to connect a producer API to the BufferQueue.  This
139     // must be called before any other IGraphicBufferProducer methods are
140     // called except for getAllocator.  A consumer must already be connected.
141     //
142     // This method will fail if connect was previously called on the
143     // BufferQueue and no corresponding disconnect call was made (i.e. if
144     // it's still connected to a producer).
145     //
146     // APIs are enumerated in window.h (e.g. NATIVE_WINDOW_API_CPU).
147     virtual status_t connect(const sp<IProducerListener>& listener,
148             int api, bool producerControlledByApp, QueueBufferOutput* output);
149 
150     // See IGraphicBufferProducer::disconnect
151     virtual status_t disconnect(int api, DisconnectMode mode = DisconnectMode::Api);
152 
153     // Attaches a sideband buffer stream to the IGraphicBufferProducer.
154     //
155     // A sideband stream is a device-specific mechanism for passing buffers
156     // from the producer to the consumer without using dequeueBuffer/
157     // queueBuffer. If a sideband stream is present, the consumer can choose
158     // whether to acquire buffers from the sideband stream or from the queued
159     // buffers.
160     //
161     // Passing NULL or a different stream handle will detach the previous
162     // handle if any.
163     virtual status_t setSidebandStream(const sp<NativeHandle>& stream);
164 
165     // See IGraphicBufferProducer::allocateBuffers
166     virtual void allocateBuffers(uint32_t width, uint32_t height,
167             PixelFormat format, uint64_t usage) override;
168 
169     // See IGraphicBufferProducer::allowAllocation
170     virtual status_t allowAllocation(bool allow);
171 
172     // See IGraphicBufferProducer::setGenerationNumber
173     virtual status_t setGenerationNumber(uint32_t generationNumber);
174 
175     // See IGraphicBufferProducer::getConsumerName
176     virtual String8 getConsumerName() const override;
177 
178     // See IGraphicBufferProducer::setSharedBufferMode
179     virtual status_t setSharedBufferMode(bool sharedBufferMode) override;
180 
181     // See IGraphicBufferProducer::setAutoRefresh
182     virtual status_t setAutoRefresh(bool autoRefresh) override;
183 
184     // See IGraphicBufferProducer::setDequeueTimeout
185     virtual status_t setDequeueTimeout(nsecs_t timeout) override;
186 
187     // see IGraphicBufferProducer::setLegacyBufferDrop
188     virtual status_t setLegacyBufferDrop(bool drop);
189 
190     // See IGraphicBufferProducer::getLastQueuedBuffer
191     virtual status_t getLastQueuedBuffer(sp<GraphicBuffer>* outBuffer,
192             sp<Fence>* outFence, float outTransformMatrix[16]) override;
193 
194     // See IGraphicBufferProducer::getLastQueuedBuffer
195     virtual status_t getLastQueuedBuffer(sp<GraphicBuffer>* outBuffer, sp<Fence>* outFence,
196                                          Rect* outRect, uint32_t* outTransform) override;
197 
198     // See IGraphicBufferProducer::getFrameTimestamps
199     virtual void getFrameTimestamps(FrameEventHistoryDelta* outDelta) override;
200 
201     // See IGraphicBufferProducer::getUniqueId
202     virtual status_t getUniqueId(uint64_t* outId) const override;
203 
204     // See IGraphicBufferProducer::getConsumerUsage
205     virtual status_t getConsumerUsage(uint64_t* outUsage) const override;
206 
207     // See IGraphicBufferProducer::setAutoPrerotation
208     virtual status_t setAutoPrerotation(bool autoPrerotation);
209 #if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BQ_SETFRAMERATE)
210     // See IGraphicBufferProducer::setFrameRate
211     status_t setFrameRate(float frameRate, int8_t compatibility,
212                           int8_t changeFrameRateStrategy) override;
213 #endif
214 
215 #if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BQ_EXTENDEDALLOCATE)
216     status_t setAdditionalOptions(const std::vector<gui::AdditionalOptions>& options) override;
217 #endif
218 
219 protected:
220     explicit BufferQueueProducer(const sp<BufferQueueCore>& core,
221                                  bool consumerIsSurfaceFlinger = false);
222     friend class sp<BufferQueueProducer>;
223     // see IGraphicsBufferProducer::setMaxDequeuedBufferCount, but with the ability to retrieve the
224     // total maximum buffer count for the buffer queue (dequeued AND acquired)
225     status_t setMaxDequeuedBufferCount(int maxDequeuedBuffers, int* maxBufferCount);
226 
227 #if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
228     // Wait until a buffer has been released. The method may spuriously return OK when no buffer has
229     // been released. The BufferQueue mutex is passed in the locked state. It must be unlocked
230     // before waiting for a release and locked before returning.
231     virtual status_t waitForBufferRelease(std::unique_lock<std::mutex>& lock,
232                                           nsecs_t timeout) const;
233 #endif
234 
235 private:
236     // This is required by the IBinder::DeathRecipient interface
237     virtual void binderDied(const wp<IBinder>& who);
238 
239     // Returns the slot of the next free buffer if one is available or
240     // BufferQueueCore::INVALID_BUFFER_SLOT otherwise
241     int getFreeBufferLocked() const;
242 
243     // Returns the next free slot if one is available or
244     // BufferQueueCore::INVALID_BUFFER_SLOT otherwise
245     int getFreeSlotLocked() const;
246 
247     void addAndGetFrameTimestamps(const NewFrameEventsEntry* newTimestamps,
248             FrameEventHistoryDelta* outDelta);
249 
250     // waitForFreeSlotThenRelock finds the oldest slot in the FREE state. It may
251     // block if there are no available slots and we are not in non-blocking
252     // mode (producer and consumer controlled by the application). If it blocks,
253     // it will release mCore->mMutex while blocked so that other operations on
254     // the BufferQueue may succeed.
255     enum class FreeSlotCaller {
256         Dequeue,
257         Attach,
258     };
259     status_t waitForFreeSlotThenRelock(FreeSlotCaller caller, std::unique_lock<std::mutex>& lock,
260             int* found) const;
261 
262     sp<BufferQueueCore> mCore;
263 
264     // This references mCore->mSlots. Lock mCore->mMutex while accessing.
265     BufferQueueDefs::SlotsType& mSlots;
266 
267     // This is a cached copy of the name stored in the BufferQueueCore.
268     // It's updated during connect and dequeueBuffer (which should catch
269     // most updates).
270     String8 mConsumerName;
271 
272     uint32_t mStickyTransform;
273 
274     // This controls whether the GraphicBuffer pointer in the BufferItem is
275     // cleared after being queued
276     bool mConsumerIsSurfaceFlinger;
277 
278     // This saves the fence from the last queueBuffer, such that the
279     // next queueBuffer call can throttle buffer production. The prior
280     // queueBuffer's fence is not nessessarily available elsewhere,
281     // since the previous buffer might have already been acquired.
282     sp<Fence> mLastQueueBufferFence;
283 
284     Rect mLastQueuedCrop;
285     uint32_t mLastQueuedTransform;
286 
287     // Take-a-ticket system for ensuring that onFrame* callbacks are called in
288     // the order that frames are queued. While the BufferQueue lock
289     // (mCore->mMutex) is held, a ticket is retained by the producer. After
290     // dropping the BufferQueue lock, the producer must wait on the condition
291     // variable until the current callback ticket matches its retained ticket.
292     std::mutex mCallbackMutex;
293     int mNextCallbackTicket; // Protected by mCore->mMutex
294     int mCurrentCallbackTicket; // Protected by mCallbackMutex
295     std::condition_variable mCallbackCondition;
296 
297     // Sets how long dequeueBuffer or attachBuffer will block if a buffer or
298     // slot is not yet available.
299     nsecs_t mDequeueTimeout;
300 
301     // If set to true, dequeueBuffer() is currently waiting for buffer allocation to complete.
302     bool mDequeueWaitingForAllocation;
303 
304     // Condition variable to signal allocateBuffers() that dequeueBuffer() is no longer waiting for
305     // allocation to complete.
306     std::condition_variable mDequeueWaitingForAllocationCondition;
307 
308 }; // class BufferQueueProducer
309 
310 } // namespace android
311 
312 #endif
313