SensorService.h revision 6c2664ae34fd582bc174d3c83e2b18e895ca2496 
1/*
2 * Copyright (C) 2010 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_H
18#define ANDROID_SENSOR_SERVICE_H
19
20#include <stdint.h>
21#include <sys/types.h>
22
23#include <utils/Vector.h>
24#include <utils/SortedVector.h>
25#include <utils/KeyedVector.h>
26#include <utils/threads.h>
27#include <utils/AndroidThreads.h>
28#include <utils/RefBase.h>
29#include <utils/Looper.h>
30
31#include <binder/BinderService.h>
32
33#include <gui/Sensor.h>
34#include <gui/BitTube.h>
35#include <gui/ISensorServer.h>
36#include <gui/ISensorEventConnection.h>
37
38#include "SensorInterface.h"
39
40// ---------------------------------------------------------------------------
41
42#define DEBUG_CONNECTIONS   false
43// Max size is 100 KB which is enough to accept a batch of about 1000 events.
44#define MAX_SOCKET_BUFFER_SIZE_BATCHED 100 * 1024
45// For older HALs which don't support batching, use a smaller socket buffer size.
46#define SOCKET_BUFFER_SIZE_NON_BATCHED 4 * 1024
47
48struct sensors_poll_device_t;
49struct sensors_module_t;
50
51namespace android {
52// ---------------------------------------------------------------------------
53
54class SensorService :
55        public BinderService<SensorService>,
56        public BnSensorServer,
57        protected Thread
58{
59    friend class BinderService<SensorService>;
60
61    static const char* WAKE_LOCK_NAME;
62
63    static char const* getServiceName() ANDROID_API { return "sensorservice"; }
64    SensorService() ANDROID_API;
65    virtual ~SensorService();
66
67    virtual void onFirstRef();
68
69    // Thread interface
70    virtual bool threadLoop();
71
72    // ISensorServer interface
73    virtual Vector<Sensor> getSensorList();
74    virtual sp<ISensorEventConnection> createSensorEventConnection();
75    virtual status_t dump(int fd, const Vector<String16>& args);
76
77    class SensorEventConnection : public BnSensorEventConnection, public LooperCallback {
78        friend class SensorService;
79        virtual ~SensorEventConnection();
80        virtual void onFirstRef();
81        virtual sp<BitTube> getSensorChannel() const;
82        virtual status_t enableDisable(int handle, bool enabled, nsecs_t samplingPeriodNs,
83                                       nsecs_t maxBatchReportLatencyNs, int reservedFlags);
84        virtual status_t setEventRate(int handle, nsecs_t samplingPeriodNs);
85        virtual status_t flush();
86        // Count the number of flush complete events which are about to be dropped in the buffer.
87        // Increment mPendingFlushEventsToSend in mSensorInfo. These flush complete events will be
88        // sent separately before the next batch of events.
89        void countFlushCompleteEventsLocked(sensors_event_t* scratch, int numEventsDropped);
90
91        // Check if there are any wake up events in the buffer. If yes, return the index of the
92        // first wake_up sensor event in the buffer else return -1. This wake_up sensor event will
93        // have the flag WAKE_UP_SENSOR_EVENT_NEEDS_ACK set. Exactly one event per packet will have
94        // the wake_up flag set. SOCK_SEQPACKET ensures that either the entire packet is read or
95        // dropped.
96        int findWakeUpSensorEventLocked(sensors_event_t const* scratch, int count);
97
98        // Send pending flush_complete events. There may have been flush_complete_events that are
99        // dropped which need to be sent separately before other events. On older HALs (1_0) this
100        // method emulates the behavior of flush().
101        void sendPendingFlushEventsLocked();
102
103        // Writes events from mEventCache to the socket.
104        void writeToSocketFromCacheLocked();
105
106        // Compute the approximate cache size from the FIFO sizes of various sensors registered for
107        // this connection. Wake up and non-wake up sensors have separate FIFOs but FIFO may be
108        // shared amongst wake-up sensors and non-wake up sensors.
109        int computeMaxCacheSizeLocked() const;
110
111        // When more sensors register, the maximum cache size desired may change. Compute max cache
112        // size, reallocate memory and copy over events from the older cache.
113        void reAllocateCacheLocked(sensors_event_t const* scratch, int count);
114
115        // LooperCallback method. If there is data to read on this fd, it is an ack from the
116        // app that it has read events from a wake up sensor, decrement mWakeLockRefCount.
117        // If this fd is available for writing send the data from the cache.
118        virtual int handleEvent(int fd, int events, void* data);
119
120        sp<SensorService> const mService;
121        sp<BitTube> mChannel;
122        uid_t mUid;
123        mutable Mutex mConnectionLock;
124        // Number of events from wake up sensors which are still pending and haven't been delivered
125        // to the corresponding application. It is incremented by one unit for each write to the
126        // socket.
127        int mWakeLockRefCount;
128
129        struct FlushInfo {
130            // The number of flush complete events dropped for this sensor is stored here.
131            // They are sent separately before the next batch of events.
132            int mPendingFlushEventsToSend;
133            // Every activate is preceded by a flush. Only after the first flush complete is
134            // received, the events for the sensor are sent on that *connection*.
135            bool mFirstFlushPending;
136            FlushInfo() : mPendingFlushEventsToSend(0), mFirstFlushPending(false) {}
137        };
138        // protected by SensorService::mLock. Key for this vector is the sensor handle.
139        KeyedVector<int, FlushInfo> mSensorInfo;
140        sensors_event_t *mEventCache;
141        int mCacheSize, mMaxCacheSize;
142
143#if DEBUG_CONNECTIONS
144        int mEventsReceived, mEventsSent, mEventsSentFromCache;
145#endif
146
147    public:
148        SensorEventConnection(const sp<SensorService>& service, uid_t uid);
149
150        status_t sendEvents(sensors_event_t const* buffer, size_t count,
151                sensors_event_t* scratch);
152        bool hasSensor(int32_t handle) const;
153        bool hasAnySensor() const;
154        bool addSensor(int32_t handle);
155        bool removeSensor(int32_t handle);
156        void setFirstFlushPending(int32_t handle, bool value);
157        void dump(String8& result);
158        bool needsWakeLock();
159
160        uid_t getUid() const { return mUid; }
161    };
162
163    class SensorRecord {
164        SortedVector< wp<SensorEventConnection> > mConnections;
165        // A queue of all flush() calls made on this sensor. Flush complete events will be
166        // sent in this order.
167        Vector< wp<SensorEventConnection> > mPendingFlushConnections;
168    public:
169        SensorRecord(const sp<SensorEventConnection>& connection);
170        bool addConnection(const sp<SensorEventConnection>& connection);
171        bool removeConnection(const wp<SensorEventConnection>& connection);
172        size_t getNumConnections() const { return mConnections.size(); }
173
174        void addPendingFlushConnection(const sp<SensorEventConnection>& connection);
175        void removeFirstPendingFlushConnection();
176        SensorEventConnection * getFirstPendingFlushConnection();
177    };
178
179    class SensorEventAckReceiver : public Thread {
180        sp<SensorService> const mService;
181    public:
182        virtual bool threadLoop();
183        SensorEventAckReceiver(const sp<SensorService>& service): mService(service) {}
184    };
185
186    String8 getSensorName(int handle) const;
187    bool isVirtualSensor(int handle) const;
188    Sensor getSensorFromHandle(int handle) const;
189    bool isWakeUpSensor(int type) const;
190    void recordLastValueLocked(const sensors_event_t* buffer, size_t count);
191    static void sortEventBuffer(sensors_event_t* buffer, size_t count);
192    Sensor registerSensor(SensorInterface* sensor);
193    Sensor registerVirtualSensor(SensorInterface* sensor);
194    status_t cleanupWithoutDisable(
195            const sp<SensorEventConnection>& connection, int handle);
196    status_t cleanupWithoutDisableLocked(
197            const sp<SensorEventConnection>& connection, int handle);
198    void cleanupAutoDisabledSensorLocked(const sp<SensorEventConnection>& connection,
199            sensors_event_t const* buffer, const int count);
200    static bool canAccessSensor(const Sensor& sensor);
201    static bool verifyCanAccessSensor(const Sensor& sensor, const char* operation);
202    // SensorService acquires a partial wakelock for delivering events from wake up sensors. This
203    // method checks whether all the events from these wake up sensors have been delivered to the
204    // corresponding applications, if yes the wakelock is released.
205    void checkWakeLockState();
206    void checkWakeLockStateLocked();
207    bool isWakeUpSensorEvent(const sensors_event_t& event) const;
208
209    SensorRecord * getSensorRecord(int handle);
210
211    sp<Looper> getLooper() const;
212
213    // constants
214    Vector<Sensor> mSensorList;
215    Vector<Sensor> mUserSensorListDebug;
216    Vector<Sensor> mUserSensorList;
217    DefaultKeyedVector<int, SensorInterface*> mSensorMap;
218    Vector<SensorInterface *> mVirtualSensorList;
219    status_t mInitCheck;
220    size_t mSocketBufferSize;
221    sp<Looper> mLooper;
222
223    // protected by mLock
224    mutable Mutex mLock;
225    DefaultKeyedVector<int, SensorRecord*> mActiveSensors;
226    DefaultKeyedVector<int, SensorInterface*> mActiveVirtualSensors;
227    SortedVector< wp<SensorEventConnection> > mActiveConnections;
228    bool mWakeLockAcquired;
229
230    // The size of this vector is constant, only the items are mutable
231    KeyedVector<int32_t, sensors_event_t> mLastEventSeen;
232
233public:
234    void cleanupConnection(SensorEventConnection* connection);
235    status_t enable(const sp<SensorEventConnection>& connection, int handle,
236                    nsecs_t samplingPeriodNs,  nsecs_t maxBatchReportLatencyNs, int reservedFlags);
237    status_t disable(const sp<SensorEventConnection>& connection, int handle);
238    status_t setEventRate(const sp<SensorEventConnection>& connection, int handle, nsecs_t ns);
239    status_t flushSensor(const sp<SensorEventConnection>& connection, int handle);
240};
241
242// ---------------------------------------------------------------------------
243}; // namespace android
244
245#endif // ANDROID_SENSOR_SERVICE_H
246