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 
23 namespace android {
24 
25 struct BufferSlot;
26 
27 class BufferQueueProducer : public BnGraphicBufferProducer,
28                             private IBinder::DeathRecipient {
29 public:
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39     // flags indicating that previously-returned buffers are no longer valid.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 
189 private:
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