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      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_EVENT_CONNECTION_H
     18 #define ANDROID_SENSOR_EVENT_CONNECTION_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 #include <utils/String8.h>
     31 
     32 #include <binder/BinderService.h>
     33 
     34 #include <sensor/Sensor.h>
     35 #include <sensor/BitTube.h>
     36 #include <sensor/ISensorServer.h>
     37 #include <sensor/ISensorEventConnection.h>
     38 
     39 #include "SensorService.h"
     40 
     41 namespace android {
     42 
     43 class SensorService;
     44 
     45 class SensorService::SensorEventConnection:
     46     public BnSensorEventConnection, public LooperCallback {
     47 
     48     friend class SensorService;
     49 
     50 public:
     51     SensorEventConnection(const sp<SensorService>& service, uid_t uid, String8 packageName,
     52                           bool isDataInjectionMode, const String16& opPackageName);
     53 
     54     status_t sendEvents(sensors_event_t const* buffer, size_t count, sensors_event_t* scratch,
     55                         wp<const SensorEventConnection> const * mapFlushEventsToConnections = NULL);
     56     bool hasSensor(int32_t handle) const;
     57     bool hasAnySensor() const;
     58     bool hasOneShotSensors() const;
     59     bool addSensor(int32_t handle);
     60     bool removeSensor(int32_t handle);
     61     void setFirstFlushPending(int32_t handle, bool value);
     62     void dump(String8& result);
     63     bool needsWakeLock();
     64     void resetWakeLockRefCount();
     65     String8 getPackageName() const;
     66 
     67     uid_t getUid() const { return mUid; }
     68 
     69 private:
     70     virtual ~SensorEventConnection();
     71     virtual void onFirstRef();
     72     virtual sp<BitTube> getSensorChannel() const;
     73     virtual status_t enableDisable(int handle, bool enabled, nsecs_t samplingPeriodNs,
     74                                    nsecs_t maxBatchReportLatencyNs, int reservedFlags);
     75     virtual status_t setEventRate(int handle, nsecs_t samplingPeriodNs);
     76     virtual status_t flush();
     77     virtual int32_t configureChannel(int handle, int rateLevel);
     78 
     79     // Count the number of flush complete events which are about to be dropped in the buffer.
     80     // Increment mPendingFlushEventsToSend in mSensorInfo. These flush complete events will be sent
     81     // separately before the next batch of events.
     82     void countFlushCompleteEventsLocked(sensors_event_t const* scratch, int numEventsDropped);
     83 
     84     // Check if there are any wake up events in the buffer. If yes, return the index of the first
     85     // wake_up sensor event in the buffer else return -1.  This wake_up sensor event will have the
     86     // flag WAKE_UP_SENSOR_EVENT_NEEDS_ACK set. Exactly one event per packet will have the wake_up
     87     // flag set. SOCK_SEQPACKET ensures that either the entire packet is read or dropped.
     88     int findWakeUpSensorEventLocked(sensors_event_t const* scratch, int count);
     89 
     90     // Send pending flush_complete events. There may have been flush_complete_events that are
     91     // dropped which need to be sent separately before other events. On older HALs (1_0) this method
     92     // emulates the behavior of flush().
     93     void sendPendingFlushEventsLocked();
     94 
     95     // Writes events from mEventCache to the socket.
     96     void writeToSocketFromCache();
     97 
     98     // Compute the approximate cache size from the FIFO sizes of various sensors registered for this
     99     // connection. Wake up and non-wake up sensors have separate FIFOs but FIFO may be shared
    100     // amongst wake-up sensors and non-wake up sensors.
    101     int computeMaxCacheSizeLocked() const;
    102 
    103     // When more sensors register, the maximum cache size desired may change.  Compute max cache
    104     // size, reallocate memory and copy over events from the older cache.
    105     void reAllocateCacheLocked(sensors_event_t const* scratch, int count);
    106 
    107     // LooperCallback method. If there is data to read on this fd, it is an ack from the app that it
    108     // has read events from a wake up sensor, decrement mWakeLockRefCount.  If this fd is available
    109     // for writing send the data from the cache.
    110     virtual int handleEvent(int fd, int events, void* data);
    111 
    112     // Increment mPendingFlushEventsToSend for the given sensor handle.
    113     void incrementPendingFlushCount(int32_t handle);
    114 
    115     // Add or remove the file descriptor associated with the BitTube to the looper. If mDead is set
    116     // to true or there are no more sensors for this connection, the file descriptor is removed if
    117     // it has been previously added to the Looper. Depending on the state of the connection FD may
    118     // be added to the Looper. The flags to set are determined by the internal state of the
    119     // connection. FDs are added to the looper when wake-up sensors are registered (to poll for
    120     // acknowledgements) and when write fails on the socket when there are too many error and the
    121     // other end hangs up or when this client unregisters for this connection.
    122     void updateLooperRegistration(const sp<Looper>& looper); void
    123             updateLooperRegistrationLocked(const sp<Looper>& looper);
    124 
    125     sp<SensorService> const mService;
    126     sp<BitTube> mChannel;
    127     uid_t mUid;
    128     mutable Mutex mConnectionLock;
    129     // Number of events from wake up sensors which are still pending and haven't been delivered to
    130     // the corresponding application. It is incremented by one unit for each write to the socket.
    131     uint32_t mWakeLockRefCount;
    132 
    133     // If this flag is set to true, it means that the file descriptor associated with the BitTube
    134     // has been added to the Looper in SensorService. This flag is typically set when this
    135     // connection has wake-up sensors associated with it or when write has failed on this connection
    136     // and we're storing some events in the cache.
    137     bool mHasLooperCallbacks;
    138     // If there are any errors associated with the Looper this flag is set to true and
    139     // mWakeLockRefCount is reset to zero. needsWakeLock method will always return false, if this
    140     // flag is set.
    141     bool mDead;
    142 
    143     bool mDataInjectionMode;
    144     struct FlushInfo {
    145         // The number of flush complete events dropped for this sensor is stored here.  They are
    146         // sent separately before the next batch of events.
    147         int mPendingFlushEventsToSend;
    148 
    149         // Every activate is preceded by a flush. Only after the first flush complete is received,
    150         // the events for the sensor are sent on that *connection*.
    151         bool mFirstFlushPending;
    152 
    153         FlushInfo() : mPendingFlushEventsToSend(0), mFirstFlushPending(false) {}
    154     };
    155     // protected by SensorService::mLock. Key for this vector is the sensor handle.
    156     KeyedVector<int, FlushInfo> mSensorInfo;
    157 
    158     sensors_event_t *mEventCache;
    159     int mCacheSize, mMaxCacheSize;
    160     String8 mPackageName;
    161     const String16 mOpPackageName;
    162 #if DEBUG_CONNECTIONS
    163     int mEventsReceived, mEventsSent, mEventsSentFromCache;
    164     int mTotalAcksNeeded, mTotalAcksReceived;
    165 #endif
    166 
    167 };
    168 
    169 } // namepsace android
    170 
    171 #endif // ANDROID_SENSOR_EVENT_CONNECTION_H
    172 
    173