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:
ConsumerListener()40     ConsumerListener() {}
41     virtual ~ConsumerListener();
42 
43     // onDisconnect is called when a producer disconnects from the BufferQueue.
onDisconnect()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.
onFrameReplaced(const BufferItem &)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.
addAndGetFrameTimestamps(const NewFrameEventsEntry *,FrameEventHistoryDelta *)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:
BnConsumerListener()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