1 /*
2  * Copyright (C) 2016 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_SENSOR_SERVICE_UTIL_RECENT_EVENT_LOGGER_H
18 #define ANDROID_SENSOR_SERVICE_UTIL_RECENT_EVENT_LOGGER_H
19 
20 #include "RingBuffer.h"
21 #include "SensorServiceUtils.h"
22 
23 #include <hardware/sensors.h>
24 #include <utils/String8.h>
25 
26 #include <mutex>
27 
28 namespace android {
29 namespace SensorServiceUtil {
30 
31 // A circular buffer that record the last N events of a sensor type for debugging. The size of this
32 // buffer depends on sensor type and is controlled by logSizeBySensorType(). The last N events
33 // generated from the sensor are stored in this buffer.  The buffer is NOT cleared when the sensor
34 // unregisters and as a result very old data in the dumpsys output can be seen, which is an intended
35 // behavior.
36 class RecentEventLogger : public Dumpable {
37 public:
38     explicit RecentEventLogger(int sensorType);
39     void addEvent(const sensors_event_t& event);
40 
41     // Populate event with the last recorded sensor event if it is not stale. An event is
42     // considered stale if the sensor has become deactivated since the event was recorded.
43     // returns true on success, false if no recent event is available or the last event is stale
44     bool populateLastEventIfCurrent(sensors_event_t *event) const;
45     bool isEmpty() const;
46     void setLastEventStale();
~RecentEventLogger()47     virtual ~RecentEventLogger() {}
48 
49     // Dumpable interface
50     virtual std::string dump() const override;
51     virtual void setFormat(std::string format) override;
52 
53 protected:
54     struct SensorEventLog {
55         explicit SensorEventLog(const sensors_event_t& e);
56         timespec mWallTime;
57         sensors_event_t mEvent;
58     };
59 
60     const int mSensorType;
61     const size_t mEventSize;
62 
63     mutable std::mutex mLock;
64     RingBuffer<SensorEventLog> mRecentEvents;
65 
66     bool mMaskData;
67     bool mIsLastEventCurrent;
68 
69 private:
70     static size_t logSizeBySensorType(int sensorType);
71 };
72 
73 } // namespace SensorServiceUtil
74 } // namespace android;
75 
76 #endif // ANDROID_SENSOR_SERVICE_UTIL_RECENT_EVENT_LOGGER_H
77 
78