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      1 /*
      2  * Copyright (C) 2013 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 #pragma once
     18 
     19 #include <binder/IInterface.h>
     20 #include <binder/SafeInterface.h>
     21 
     22 #include <utils/Errors.h>
     23 #include <utils/RefBase.h>
     24 
     25 #include <cstdint>
     26 
     27 namespace android {
     28 
     29 class BufferItem;
     30 class FrameEventHistoryDelta;
     31 struct NewFrameEventsEntry;
     32 
     33 // ConsumerListener is the interface through which the BufferQueue notifies the consumer of events
     34 // that the consumer may wish to react to. Because the consumer will generally have a mutex that is
     35 // locked during calls from the consumer to the BufferQueue, these calls from the BufferQueue to the
     36 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked.
     37 
     38 class ConsumerListener : public virtual RefBase {
     39 public:
     40     ConsumerListener() {}
     41     virtual ~ConsumerListener();
     42 
     43     // onDisconnect is called when a producer disconnects from the BufferQueue.
     44     virtual void onDisconnect() {} /* Asynchronous */
     45 
     46     // onFrameAvailable is called from queueBuffer each time an additional frame becomes available
     47     // for consumption. This means that frames that are queued while in asynchronous mode only
     48     // trigger the callback if no previous frames are pending. Frames queued while in synchronous
     49     // mode always trigger the callback. The item passed to the callback will contain all of the
     50     // information about the queued frame except for its GraphicBuffer pointer, which will always be
     51     // null (except if the consumer is SurfaceFlinger).
     52     //
     53     // This is called without any lock held and can be called concurrently by multiple threads.
     54     virtual void onFrameAvailable(const BufferItem& item) = 0; /* Asynchronous */
     55 
     56     // onFrameReplaced is called from queueBuffer if the frame being queued is replacing an existing
     57     // slot in the queue. Any call to queueBuffer that doesn't call onFrameAvailable will call this
     58     // callback instead. The item passed to the callback will contain all of the information about
     59     // the queued frame except for its GraphicBuffer pointer, which will always be null.
     60     //
     61     // This is called without any lock held and can be called concurrently by multiple threads.
     62     virtual void onFrameReplaced(const BufferItem& /* item */) {} /* Asynchronous */
     63 
     64     // onBuffersReleased is called to notify the buffer consumer that the BufferQueue has released
     65     // its references to one or more GraphicBuffers contained in its slots. The buffer consumer
     66     // should then call BufferQueue::getReleasedBuffers to retrieve the list of buffers.
     67     //
     68     // This is called without any lock held and can be called concurrently by multiple threads.
     69     virtual void onBuffersReleased() = 0; /* Asynchronous */
     70 
     71     // onSidebandStreamChanged is called to notify the buffer consumer that the BufferQueue's
     72     // sideband buffer stream has changed. This is called when a stream is first attached and when
     73     // it is either detached or replaced by a different stream.
     74     virtual void onSidebandStreamChanged() = 0; /* Asynchronous */
     75 
     76     // Notifies the consumer of any new producer-side timestamps and returns the combined frame
     77     // history that hasn't already been retrieved.
     78     //
     79     // WARNING: This method can only be called when the BufferQueue is in the consumer's process.
     80     virtual void addAndGetFrameTimestamps(const NewFrameEventsEntry* /*newTimestamps*/,
     81                                           FrameEventHistoryDelta* /*outDelta*/) {}
     82 };
     83 
     84 class IConsumerListener : public ConsumerListener, public IInterface {
     85 public:
     86     DECLARE_META_INTERFACE(ConsumerListener)
     87 };
     88 
     89 class BnConsumerListener : public SafeBnInterface<IConsumerListener> {
     90 public:
     91     BnConsumerListener() : SafeBnInterface<IConsumerListener>("BnConsumerListener") {}
     92 
     93     status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply,
     94                         uint32_t flags = 0) override;
     95 };
     96 
     97 } // namespace android
     98