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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_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 
     48 struct sensors_poll_device_t;
     49 struct sensors_module_t;
     50 
     51 namespace android {
     52 // ---------------------------------------------------------------------------
     53 
     54 class 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 const* 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 writeToSocketFromCache();
    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         // Increment mPendingFlushEventsToSend for the given sensor handle.
    121         void incrementPendingFlushCount(int32_t handle);
    122 
    123         // Add or remove the file descriptor associated with the BitTube to the looper. If mDead is
    124         // set to true or there are no more sensors for this connection, the file descriptor is
    125         // removed if it has been previously added to the Looper. Depending on the state of the
    126         // connection FD may be added to the Looper. The flags to set are determined by the internal
    127         // state of the connection. FDs are added to the looper when wake-up sensors are registered
    128         // (to poll for acknowledgements) and when write fails on the socket when there are too many
    129         // events (to poll when the FD is available for writing). FDs are removed when there is an
    130         // error and the other end hangs up or when this client unregisters for this connection.
    131         void updateLooperRegistration(const sp<Looper>& looper);
    132         void updateLooperRegistrationLocked(const sp<Looper>& looper);
    133 
    134         sp<SensorService> const mService;
    135         sp<BitTube> mChannel;
    136         uid_t mUid;
    137         mutable Mutex mConnectionLock;
    138         // Number of events from wake up sensors which are still pending and haven't been delivered
    139         // to the corresponding application. It is incremented by one unit for each write to the
    140         // socket.
    141         uint32_t mWakeLockRefCount;
    142 
    143         // If this flag is set to true, it means that the file descriptor associated with the
    144         // BitTube has been added to the Looper in SensorService. This flag is typically set when
    145         // this connection has wake-up sensors associated with it or when write has failed on this
    146         // connection and we're storing some events in the cache.
    147         bool mHasLooperCallbacks;
    148         // If there are any errors associated with the Looper this flag is set to true and
    149         // mWakeLockRefCount is reset to zero. needsWakeLock method will always return false, if
    150         // this flag is set.
    151         bool mDead;
    152         struct FlushInfo {
    153             // The number of flush complete events dropped for this sensor is stored here.
    154             // They are sent separately before the next batch of events.
    155             int mPendingFlushEventsToSend;
    156             // Every activate is preceded by a flush. Only after the first flush complete is
    157             // received, the events for the sensor are sent on that *connection*.
    158             bool mFirstFlushPending;
    159             FlushInfo() : mPendingFlushEventsToSend(0), mFirstFlushPending(false) {}
    160         };
    161         // protected by SensorService::mLock. Key for this vector is the sensor handle.
    162         KeyedVector<int, FlushInfo> mSensorInfo;
    163         sensors_event_t *mEventCache;
    164         int mCacheSize, mMaxCacheSize;
    165 
    166 #if DEBUG_CONNECTIONS
    167         int mEventsReceived, mEventsSent, mEventsSentFromCache;
    168         int mTotalAcksNeeded, mTotalAcksReceived;
    169 #endif
    170 
    171     public:
    172         SensorEventConnection(const sp<SensorService>& service, uid_t uid);
    173 
    174         status_t sendEvents(sensors_event_t const* buffer, size_t count,
    175                 sensors_event_t* scratch,
    176                 SensorEventConnection const * const * mapFlushEventsToConnections = NULL);
    177         bool hasSensor(int32_t handle) const;
    178         bool hasAnySensor() const;
    179         bool hasOneShotSensors() const;
    180         bool addSensor(int32_t handle);
    181         bool removeSensor(int32_t handle);
    182         void setFirstFlushPending(int32_t handle, bool value);
    183         void dump(String8& result);
    184         bool needsWakeLock();
    185         void resetWakeLockRefCount();
    186 
    187         uid_t getUid() const { return mUid; }
    188     };
    189 
    190     class SensorRecord {
    191         SortedVector< wp<SensorEventConnection> > mConnections;
    192         // A queue of all flush() calls made on this sensor. Flush complete events will be
    193         // sent in this order.
    194         Vector< wp<SensorEventConnection> > mPendingFlushConnections;
    195     public:
    196         SensorRecord(const sp<SensorEventConnection>& connection);
    197         bool addConnection(const sp<SensorEventConnection>& connection);
    198         bool removeConnection(const wp<SensorEventConnection>& connection);
    199         size_t getNumConnections() const { return mConnections.size(); }
    200 
    201         void addPendingFlushConnection(const sp<SensorEventConnection>& connection);
    202         void removeFirstPendingFlushConnection();
    203         SensorEventConnection * getFirstPendingFlushConnection();
    204     };
    205 
    206     class SensorEventAckReceiver : public Thread {
    207         sp<SensorService> const mService;
    208     public:
    209         virtual bool threadLoop();
    210         SensorEventAckReceiver(const sp<SensorService>& service): mService(service) {}
    211     };
    212 
    213     String8 getSensorName(int handle) const;
    214     bool isVirtualSensor(int handle) const;
    215     Sensor getSensorFromHandle(int handle) const;
    216     bool isWakeUpSensor(int type) const;
    217     void recordLastValueLocked(sensors_event_t const* buffer, size_t count);
    218     static void sortEventBuffer(sensors_event_t* buffer, size_t count);
    219     Sensor registerSensor(SensorInterface* sensor);
    220     Sensor registerVirtualSensor(SensorInterface* sensor);
    221     status_t cleanupWithoutDisable(
    222             const sp<SensorEventConnection>& connection, int handle);
    223     status_t cleanupWithoutDisableLocked(
    224             const sp<SensorEventConnection>& connection, int handle);
    225     void cleanupAutoDisabledSensorLocked(const sp<SensorEventConnection>& connection,
    226             sensors_event_t const* buffer, const int count);
    227     static bool canAccessSensor(const Sensor& sensor);
    228     static bool verifyCanAccessSensor(const Sensor& sensor, const char* operation);
    229     // SensorService acquires a partial wakelock for delivering events from wake up sensors. This
    230     // method checks whether all the events from these wake up sensors have been delivered to the
    231     // corresponding applications, if yes the wakelock is released.
    232     void checkWakeLockState();
    233     void checkWakeLockStateLocked();
    234     bool isWakeLockAcquired();
    235     bool isWakeUpSensorEvent(const sensors_event_t& event) const;
    236 
    237     SensorRecord * getSensorRecord(int handle);
    238 
    239     sp<Looper> getLooper() const;
    240 
    241     // Reset mWakeLockRefCounts for all SensorEventConnections to zero. This may happen if
    242     // SensorService did not receive any acknowledgements from apps which have registered for
    243     // wake_up sensors.
    244     void resetAllWakeLockRefCounts();
    245 
    246     // Acquire or release wake_lock. If wake_lock is acquired, set the timeout in the looper to
    247     // 5 seconds and wake the looper.
    248     void setWakeLockAcquiredLocked(bool acquire);
    249 
    250     // Send events from the event cache for this particular connection.
    251     void sendEventsFromCache(const sp<SensorEventConnection>& connection);
    252 
    253     // Promote all weak referecences in mActiveConnections vector to strong references and add them
    254     // to the output vector.
    255     void populateActiveConnections(SortedVector< sp<SensorEventConnection> >* activeConnections);
    256 
    257     // constants
    258     Vector<Sensor> mSensorList;
    259     Vector<Sensor> mUserSensorListDebug;
    260     Vector<Sensor> mUserSensorList;
    261     DefaultKeyedVector<int, SensorInterface*> mSensorMap;
    262     Vector<SensorInterface *> mVirtualSensorList;
    263     status_t mInitCheck;
    264     // Socket buffersize used to initialize BitTube. This size depends on whether batching is
    265     // supported or not.
    266     uint32_t mSocketBufferSize;
    267     sp<Looper> mLooper;
    268     sp<SensorEventAckReceiver> mAckReceiver;
    269 
    270     // protected by mLock
    271     mutable Mutex mLock;
    272     DefaultKeyedVector<int, SensorRecord*> mActiveSensors;
    273     DefaultKeyedVector<int, SensorInterface*> mActiveVirtualSensors;
    274     SortedVector< wp<SensorEventConnection> > mActiveConnections;
    275     bool mWakeLockAcquired;
    276     sensors_event_t *mSensorEventBuffer, *mSensorEventScratch;
    277     SensorEventConnection const **mMapFlushEventsToConnections;
    278 
    279     // The size of this vector is constant, only the items are mutable
    280     KeyedVector<int32_t, sensors_event_t> mLastEventSeen;
    281 
    282 public:
    283     void cleanupConnection(SensorEventConnection* connection);
    284     status_t enable(const sp<SensorEventConnection>& connection, int handle,
    285                     nsecs_t samplingPeriodNs,  nsecs_t maxBatchReportLatencyNs, int reservedFlags);
    286     status_t disable(const sp<SensorEventConnection>& connection, int handle);
    287     status_t setEventRate(const sp<SensorEventConnection>& connection, int handle, nsecs_t ns);
    288     status_t flushSensor(const sp<SensorEventConnection>& connection);
    289 };
    290 
    291 // ---------------------------------------------------------------------------
    292 }; // namespace android
    293 
    294 #endif // ANDROID_SENSOR_SERVICE_H
    295