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 class 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);
33     virtual ~BufferQueueProducer();
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39     // flags indicating that previously-returned buffers are no longer valid.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,
84             uint32_t width, uint32_t height, PixelFormat format,
85             uint32_t usage);
86 
87     // See IGraphicBufferProducer::detachBuffer
88     virtual status_t detachBuffer(int slot);
89 
90     // See IGraphicBufferProducer::detachNextBuffer
91     virtual status_t detachNextBuffer(sp<GraphicBuffer>* outBuffer,
92             sp<Fence>* outFence);
93 
94     // See IGraphicBufferProducer::attachBuffer
95     virtual status_t attachBuffer(int* outSlot, const sp<GraphicBuffer>& buffer);
96 
97     // queueBuffer returns a filled buffer to the BufferQueue.
98     //
99     // Additional data is provided in the QueueBufferInput struct.  Notably,
100     // a timestamp must be provided for the buffer. The timestamp is in
101     // nanoseconds, and must be monotonically increasing. Its other semantics
102     // (zero point, etc) are producer-specific and should be documented by the
103     // producer.
104     //
105     // The caller may provide a fence that signals when all rendering
106     // operations have completed.  Alternatively, NO_FENCE may be used,
107     // indicating that the buffer is ready immediately.
108     //
109     // Some values are returned in the output struct: the current settings
110     // for default width and height, the current transform hint, and the
111     // number of queued buffers.
112     virtual status_t queueBuffer(int slot,
113             const QueueBufferInput& input, QueueBufferOutput* output);
114 
115     // cancelBuffer returns a dequeued buffer to the BufferQueue, but doesn't
116     // queue it for use by the consumer.
117     //
118     // The buffer will not be overwritten until the fence signals.  The fence
119     // will usually be the one obtained from dequeueBuffer.
120     virtual status_t cancelBuffer(int slot, const sp<Fence>& fence);
121 
122     // Query native window attributes.  The "what" values are enumerated in
123     // window.h (e.g. NATIVE_WINDOW_FORMAT).
124     virtual int query(int what, int* outValue);
125 
126     // connect attempts to connect a producer API to the BufferQueue.  This
127     // must be called before any other IGraphicBufferProducer methods are
128     // called except for getAllocator.  A consumer must already be connected.
129     //
130     // This method will fail if connect was previously called on the
131     // BufferQueue and no corresponding disconnect call was made (i.e. if
132     // it's still connected to a producer).
133     //
134     // APIs are enumerated in window.h (e.g. NATIVE_WINDOW_API_CPU).
135     virtual status_t connect(const sp<IProducerListener>& listener,
136             int api, bool producerControlledByApp, QueueBufferOutput* output);
137 
138     // disconnect attempts to disconnect a producer API from the BufferQueue.
139     // Calling this method will cause any subsequent calls to other
140     // IGraphicBufferProducer methods to fail except for getAllocator and connect.
141     // Successfully calling connect after this will allow the other methods to
142     // succeed again.
143     //
144     // This method will fail if the the BufferQueue is not currently
145     // connected to the specified producer API.
146     virtual status_t disconnect(int api);
147 
148     // Attaches a sideband buffer stream to the IGraphicBufferProducer.
149     //
150     // A sideband stream is a device-specific mechanism for passing buffers
151     // from the producer to the consumer without using dequeueBuffer/
152     // queueBuffer. If a sideband stream is present, the consumer can choose
153     // whether to acquire buffers from the sideband stream or from the queued
154     // buffers.
155     //
156     // Passing NULL or a different stream handle will detach the previous
157     // handle if any.
158     virtual status_t setSidebandStream(const sp<NativeHandle>& stream);
159 
160     // See IGraphicBufferProducer::allocateBuffers
161     virtual void allocateBuffers(uint32_t width, uint32_t height,
162             PixelFormat format, uint32_t usage);
163 
164     // See IGraphicBufferProducer::allowAllocation
165     virtual status_t allowAllocation(bool allow);
166 
167     // See IGraphicBufferProducer::setGenerationNumber
168     virtual status_t setGenerationNumber(uint32_t generationNumber);
169 
170     // See IGraphicBufferProducer::getConsumerName
171     virtual String8 getConsumerName() const override;
172 
173     // See IGraphicBufferProducer::getNextFrameNumber
174     virtual uint64_t getNextFrameNumber() const override;
175 
176     // See IGraphicBufferProducer::setSharedBufferMode
177     virtual status_t setSharedBufferMode(bool sharedBufferMode) override;
178 
179     // See IGraphicBufferProducer::setAutoRefresh
180     virtual status_t setAutoRefresh(bool autoRefresh) override;
181 
182     // See IGraphicBufferProducer::setDequeueTimeout
183     virtual status_t setDequeueTimeout(nsecs_t timeout) override;
184 
185     // See IGraphicBufferProducer::getLastQueuedBuffer
186     virtual status_t getLastQueuedBuffer(sp<GraphicBuffer>* outBuffer,
187             sp<Fence>* outFence, float outTransformMatrix[16]) override;
188 
189     // See IGraphicBufferProducer::getUniqueId
190     virtual status_t getUniqueId(uint64_t* outId) const override;
191 
192 private:
193     // This is required by the IBinder::DeathRecipient interface
194     virtual void binderDied(const wp<IBinder>& who);
195 
196     // Returns the slot of the next free buffer if one is available or
197     // BufferQueueCore::INVALID_BUFFER_SLOT otherwise
198     int getFreeBufferLocked() const;
199 
200     // Returns the next free slot if one is available or
201     // BufferQueueCore::INVALID_BUFFER_SLOT otherwise
202     int getFreeSlotLocked() const;
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 saves the fence from the last queueBuffer, such that the
228     // next queueBuffer call can throttle buffer production. The prior
229     // queueBuffer's fence is not nessessarily available elsewhere,
230     // since the previous buffer might have already been acquired.
231     sp<Fence> mLastQueueBufferFence;
232 
233     Rect mLastQueuedCrop;
234     uint32_t mLastQueuedTransform;
235 
236     // Take-a-ticket system for ensuring that onFrame* callbacks are called in
237     // the order that frames are queued. While the BufferQueue lock
238     // (mCore->mMutex) is held, a ticket is retained by the producer. After
239     // dropping the BufferQueue lock, the producer must wait on the condition
240     // variable until the current callback ticket matches its retained ticket.
241     Mutex mCallbackMutex;
242     int mNextCallbackTicket; // Protected by mCore->mMutex
243     int mCurrentCallbackTicket; // Protected by mCallbackMutex
244     Condition mCallbackCondition;
245 
246     // Sets how long dequeueBuffer or attachBuffer will block if a buffer or
247     // slot is not yet available.
248     nsecs_t mDequeueTimeout;
249 
250 }; // class BufferQueueProducer
251 
252 } // namespace android
253 
254 #endif
255