1 /*
2  * Copyright 2019 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 <chrono>
20 #include <condition_variable>
21 #include <mutex>
22 #include <thread>
23 #include <unordered_map>
24 
25 #include <android-base/thread_annotations.h>
26 #include <binder/IBinder.h>
27 #include <ui/GraphicBuffer.h>
28 #include <ui/Rect.h>
29 #include <utils/StrongPointer.h>
30 #include "Scheduler/IdleTimer.h"
31 
32 namespace android {
33 
34 class IRegionSamplingListener;
35 class Layer;
36 class Scheduler;
37 class SurfaceFlinger;
38 struct SamplingOffsetCallback;
39 
40 float sampleArea(const uint32_t* data, int32_t width, int32_t height, int32_t stride,
41                  uint32_t orientation, const Rect& area);
42 
43 class RegionSamplingThread : public IBinder::DeathRecipient {
44 public:
45     struct TimingTunables {
46         // debug.sf.sampling_offset_ns
47         // When asynchronously collecting sample, the offset, from zero phase in the vsync timeline
48         // at which the sampling should start.
49         std::chrono::nanoseconds mSamplingOffset;
50         // debug.sf.sampling_period_ns
51         // This is the maximum amount of time the luma recieving client
52         // should have to wait for a new luma value after a frame is updated. The inverse of this is
53         // roughly the sampling rate. Sampling system rounds up sub-vsync sampling period to vsync
54         // period.
55         std::chrono::nanoseconds mSamplingPeriod;
56         // debug.sf.sampling_timer_timeout_ns
57         // This is the interval at which the luma sampling system will check that the luma clients
58         // have up to date information. It defaults to the mSamplingPeriod.
59         std::chrono::nanoseconds mSamplingTimerTimeout;
60     };
61     struct EnvironmentTimingTunables : TimingTunables {
62         EnvironmentTimingTunables();
63     };
64     explicit RegionSamplingThread(SurfaceFlinger& flinger, Scheduler& scheduler,
65                                   const TimingTunables& tunables);
66     explicit RegionSamplingThread(SurfaceFlinger& flinger, Scheduler& scheduler);
67 
68     ~RegionSamplingThread();
69 
70     // Add a listener to receive luma notifications. The luma reported via listener will
71     // report the median luma for the layers under the stopLayerHandle, in the samplingArea region.
72     void addListener(const Rect& samplingArea, const sp<IBinder>& stopLayerHandle,
73                      const sp<IRegionSamplingListener>& listener);
74     // Remove the listener to stop receiving median luma notifications.
75     void removeListener(const sp<IRegionSamplingListener>& listener);
76 
77     // Notifies sampling engine that new content is available. This will trigger a sampling
78     // pass at some point in the future.
79     void notifyNewContent();
80 
81     // Notifies the sampling engine that it has a good timing window in which to sample.
82     void notifySamplingOffset();
83 
84 private:
85     struct Descriptor {
86         Rect area = Rect::EMPTY_RECT;
87         wp<Layer> stopLayer;
88         sp<IRegionSamplingListener> listener;
89     };
90 
91     struct WpHash {
operatorWpHash92         size_t operator()(const wp<IBinder>& p) const {
93             return std::hash<IBinder*>()(p.unsafe_get());
94         }
95     };
96     std::vector<float> sampleBuffer(
97             const sp<GraphicBuffer>& buffer, const Point& leftTop,
98             const std::vector<RegionSamplingThread::Descriptor>& descriptors, uint32_t orientation);
99 
100     void doSample();
101     void binderDied(const wp<IBinder>& who) override;
102     void checkForStaleLuma();
103 
104     void captureSample();
105     void threadMain();
106 
107     SurfaceFlinger& mFlinger;
108     Scheduler& mScheduler;
109     const TimingTunables mTunables;
110     scheduler::IdleTimer mIdleTimer;
111 
112     std::unique_ptr<SamplingOffsetCallback> const mPhaseCallback;
113 
114     std::thread mThread;
115 
116     std::mutex mThreadControlMutex;
117     std::condition_variable_any mCondition;
118     bool mRunning GUARDED_BY(mThreadControlMutex) = true;
119     bool mSampleRequested GUARDED_BY(mThreadControlMutex) = false;
120     uint32_t mDiscardedFrames GUARDED_BY(mThreadControlMutex) = 0;
121     std::chrono::nanoseconds lastSampleTime GUARDED_BY(mThreadControlMutex);
122 
123     std::mutex mSamplingMutex;
124     std::unordered_map<wp<IBinder>, Descriptor, WpHash> mDescriptors GUARDED_BY(mSamplingMutex);
125     sp<GraphicBuffer> mCachedBuffer GUARDED_BY(mSamplingMutex) = nullptr;
126 };
127 
128 } // namespace android
129