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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 #ifndef ANDROID_GUI_ICONSUMERLISTENER_H
     18 #define ANDROID_GUI_ICONSUMERLISTENER_H
     19 
     20 #include <stdint.h>
     21 #include <sys/types.h>
     22 
     23 #include <utils/Errors.h>
     24 #include <utils/RefBase.h>
     25 
     26 #include <binder/IInterface.h>
     27 
     28 namespace android {
     29 // ----------------------------------------------------------------------------
     30 
     31 class BufferItem;
     32 
     33 // ConsumerListener is the interface through which the BufferQueue notifies
     34 // the consumer of events that the consumer may wish to react to.  Because
     35 // the consumer will generally have a mutex that is locked during calls from
     36 // the consumer to the BufferQueue, these calls from the BufferQueue to the
     37 // consumer *MUST* be called only when the BufferQueue mutex is NOT locked.
     38 
     39 class ConsumerListener : public virtual RefBase {
     40 public:
     41     ConsumerListener() { }
     42     virtual ~ConsumerListener() { }
     43 
     44     // onFrameAvailable is called from queueBuffer each time an additional
     45     // frame becomes available for consumption. This means that frames that
     46     // are queued while in asynchronous mode only trigger the callback if no
     47     // previous frames are pending. Frames queued while in synchronous mode
     48     // always trigger the callback. The item passed to the callback will contain
     49     // all of the information about the queued frame except for its
     50     // GraphicBuffer pointer, which will always be null.
     51     //
     52     // This is called without any lock held and can be called concurrently
     53     // 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
     57     // replacing an existing slot in the queue. Any call to queueBuffer that
     58     // doesn't call onFrameAvailable will call this callback instead. The item
     59     // passed to the callback will contain all of the information about the
     60     // queued frame except for its GraphicBuffer pointer, which will always be
     61     // null.
     62     //
     63     // This is called without any lock held and can be called concurrently
     64     // by multiple threads.
     65     virtual void onFrameReplaced(const BufferItem& /* item */) {} /* Asynchronous */
     66 
     67     // onBuffersReleased is called to notify the buffer consumer that the
     68     // BufferQueue has released its references to one or more GraphicBuffers
     69     // contained in its slots.  The buffer consumer should then call
     70     // BufferQueue::getReleasedBuffers to retrieve the list of buffers
     71     //
     72     // This is called without any lock held and can be called concurrently
     73     // by multiple threads.
     74     virtual void onBuffersReleased() = 0; /* Asynchronous */
     75 
     76     // onSidebandStreamChanged is called to notify the buffer consumer that the
     77     // BufferQueue's sideband buffer stream has changed. This is called when a
     78     // stream is first attached and when it is either detached or replaced by a
     79     // different stream.
     80     virtual void onSidebandStreamChanged() = 0; /* Asynchronous */
     81 };
     82 
     83 
     84 class IConsumerListener : public ConsumerListener, public IInterface
     85 {
     86 public:
     87     DECLARE_META_INTERFACE(ConsumerListener);
     88 };
     89 
     90 // ----------------------------------------------------------------------------
     91 
     92 class BnConsumerListener : public BnInterface<IConsumerListener>
     93 {
     94 public:
     95     virtual status_t    onTransact( uint32_t code,
     96                                     const Parcel& data,
     97                                     Parcel* reply,
     98                                     uint32_t flags = 0);
     99 };
    100 
    101 // ----------------------------------------------------------------------------
    102 }; // namespace android
    103 
    104 #endif // ANDROID_GUI_ICONSUMERLISTENER_H
    105