fix [3237242] sensormanager sensor active count gets out of sync

whether a physical sensor needed to be active or not was managed by
a simpe reference counter; unfortunatelly nothing prevented it to
get out of sync if a sensor was disabled more than once.

sensorservice already maintainted a list of all the "clients"
connected to a physical sensor; we now use that list to determine if
a sensor should be enabled. This can never be "out-of-sync" since
this is the only data structure linking a sensor to a user of that
sensor.

also removed the isEnabled() method, which was never used and
implemented wrongly (since it didn't take into account that a sensor
could be disabled for a client but not of another).

Change-Id: I789affb877728ca957e99f7ba749def37c4db1c7

services/sensorservice/GravitySensor.cpp

@@ -29,7 +29,7 @@ namespace android {
 
 GravitySensor::GravitySensor(sensor_t const* list, size_t count)
     : mSensorDevice(SensorDevice::getInstance()),
-      mEnabled(false), mAccTime(0),
+      mAccTime(0),
       mLowPass(M_SQRT1_2, 1.5f),
       mX(mLowPass), mY(mLowPass), mZ(mLowPass)
 
@@ -71,15 +71,9 @@ bool GravitySensor::process(sensors_event_t* outEvent,
     }
     return false;
 }
-
-bool GravitySensor::isEnabled() const {
-    return mEnabled;
-}
-
 status_t GravitySensor::activate(void* ident, bool enabled) {
     status_t err = mSensorDevice.activate(this, mAccelerometer.getHandle(), enabled);
     if (err == NO_ERROR) {
-        mEnabled = enabled;
         if (enabled) {
             mAccTime = 0;
         }

services/sensorservice/GravitySensor.h

@@ -33,7 +33,6 @@ namespace android {
 class GravitySensor : public SensorInterface {
     SensorDevice& mSensorDevice;
     Sensor mAccelerometer;
-    bool mEnabled;
     double mAccTime;
 
     SecondOrderLowPassFilter mLowPass;
@@ -43,7 +42,6 @@ public:
     GravitySensor(sensor_t const* list, size_t count);
     virtual bool process(sensors_event_t* outEvent,
             const sensors_event_t& event);
-    virtual bool isEnabled() const;
     virtual status_t activate(void* ident, bool enabled);
     virtual status_t setDelay(void* ident, int handle, int64_t ns);
     virtual Sensor getSensor() const;

services/sensorservice/LinearAccelerationSensor.cpp

@@ -53,10 +53,6 @@ bool LinearAccelerationSensor::process(sensors_event_t* outEvent,
     return result;
 }
 
-bool LinearAccelerationSensor::isEnabled() const {
-    return mGravitySensor.isEnabled();
-}
-
 status_t LinearAccelerationSensor::activate(void* ident, bool enabled) {
     return mGravitySensor.activate(ident, enabled);
 }

services/sensorservice/LinearAccelerationSensor.h

@@ -40,7 +40,6 @@ class LinearAccelerationSensor : public SensorInterface {
             const sensors_event_t& event);
 public:
     LinearAccelerationSensor(sensor_t const* list, size_t count);
-    virtual bool isEnabled() const;
     virtual status_t activate(void* ident, bool enabled);
     virtual status_t setDelay(void* ident, int handle, int64_t ns);
     virtual Sensor getSensor() const;

services/sensorservice/RotationVectorSensor.cpp

@@ -34,7 +34,6 @@ static inline T clamp(T v) {
 
 RotationVectorSensor::RotationVectorSensor(sensor_t const* list, size_t count)
     : mSensorDevice(SensorDevice::getInstance()),
-      mEnabled(false),
       mALowPass(M_SQRT1_2, 5.0f),
       mAX(mALowPass), mAY(mALowPass), mAZ(mALowPass),
       mMLowPass(M_SQRT1_2, 2.5f),
@@ -133,19 +132,12 @@ bool RotationVectorSensor::process(sensors_event_t* outEvent,
     return false;
 }
 
-bool RotationVectorSensor::isEnabled() const {
-    return mEnabled;
-}
-
 status_t RotationVectorSensor::activate(void* ident, bool enabled) {
-    if (mEnabled != enabled) {
+    mSensorDevice.activate(this, mAcc.getHandle(), enabled);
-        mSensorDevice.activate(this, mAcc.getHandle(), enabled);
+    mSensorDevice.activate(this, mMag.getHandle(), enabled);
-        mSensorDevice.activate(this, mMag.getHandle(), enabled);
+    if (enabled) {
-        mEnabled = enabled;
+        mMagTime = 0;
-        if (enabled) {
+        mAccTime = 0;
-            mMagTime = 0;
-            mAccTime = 0;
-        }
     }
     return NO_ERROR;
 }

services/sensorservice/RotationVectorSensor.h

@@ -34,7 +34,6 @@ class RotationVectorSensor : public SensorInterface {
     SensorDevice& mSensorDevice;
     Sensor mAcc;
     Sensor mMag;
-    bool mEnabled;
     float mMagData[3];
     double mAccTime;
     double mMagTime;
@@ -47,7 +46,6 @@ public:
     RotationVectorSensor(sensor_t const* list, size_t count);
     virtual bool process(sensors_event_t* outEvent,
             const sensors_event_t& event);
-    virtual bool isEnabled() const;
     virtual status_t activate(void* ident, bool enabled);
     virtual status_t setDelay(void* ident, int handle, int64_t ns);
     virtual Sensor getSensor() const;

services/sensorservice/SensorDevice.cpp

@@ -137,9 +137,8 @@ void SensorDevice::dump(String8& result, char* buffer, size_t SIZE)
 
     Mutex::Autolock _l(mLock);
     for (size_t i=0 ; i<size_t(count) ; i++) {
-        snprintf(buffer, SIZE, "handle=0x%08x, active-count=%d / %d\n",
+        snprintf(buffer, SIZE, "handle=0x%08x, active-count=%d\n",
                 list[i].handle,
-                mActivationCount.valueFor(list[i].handle).count,
                 mActivationCount.valueFor(list[i].handle).rates.size());
         result.append(buffer);
     }
@@ -167,22 +166,25 @@ status_t SensorDevice::activate(void* ident, int handle, int enabled)
     bool actuateHardware = false;
 
     Info& info( mActivationCount.editValueFor(handle) );
-    int32_t& count(info.count);
     if (enabled) {
-        if (android_atomic_inc(&count) == 0) {
-            actuateHardware = true;
-        }
         Mutex::Autolock _l(mLock);
         if (info.rates.indexOfKey(ident) < 0) {
             info.rates.add(ident, DEFAULT_EVENTS_PERIOD);
+            actuateHardware = true;
+        } else {
+            // sensor was already activated for this ident
         }
     } else {
-        if (android_atomic_dec(&count) == 1) {
-            actuateHardware = true;
-        }
         Mutex::Autolock _l(mLock);
-        info.rates.removeItem(ident);
+        if (info.rates.removeItem(ident) >= 0) {
+            if (info.rates.size() == 0) {
+                actuateHardware = true;
+            }
+        } else {
+            // sensor wasn't enabled for this ident
+        }
     }
+
     if (actuateHardware) {
         err = mSensorDevice->activate(mSensorDevice, handle, enabled);
         if (enabled) {

services/sensorservice/SensorDevice.h

@@ -40,8 +40,7 @@ class SensorDevice : public Singleton<SensorDevice> {
     Mutex mLock; // protect mActivationCount[].rates
     // fixed-size array after construction
     struct Info {
-        Info() : count(0) { }
+        Info() { }
-        int32_t count;
         KeyedVector<void*, nsecs_t> rates;
     };
     DefaultKeyedVector<int, Info> mActivationCount;

services/sensorservice/SensorInterface.cpp

@@ -32,7 +32,7 @@ SensorInterface::~SensorInterface()
 
 HardwareSensor::HardwareSensor(const sensor_t& sensor)
     : mSensorDevice(SensorDevice::getInstance()),
-      mSensor(&sensor), mEnabled(false)
+      mSensor(&sensor)
 {
     LOGI("%s", sensor.name);
 }
@@ -46,15 +46,8 @@ bool HardwareSensor::process(sensors_event_t* outEvent,
     return true;
 }
 
-bool HardwareSensor::isEnabled() const {
+status_t HardwareSensor::activate(void* ident, bool enabled) {
-    return mEnabled;
+    return mSensorDevice.activate(ident, mSensor.getHandle(), enabled);
-}
-
-status_t HardwareSensor::activate(void* ident,bool enabled) {
-    status_t err = mSensorDevice.activate(ident, mSensor.getHandle(), enabled);
-    if (err == NO_ERROR)
-        mEnabled = enabled;
-    return err;
 }
 
 status_t HardwareSensor::setDelay(void* ident, int handle, int64_t ns) {

services/sensorservice/SensorInterface.h

@@ -38,7 +38,6 @@ public:
     virtual bool process(sensors_event_t* outEvent,
             const sensors_event_t& event) = 0;
 
-    virtual bool isEnabled() const = 0;
     virtual status_t activate(void* ident, bool enabled) = 0;
     virtual status_t setDelay(void* ident, int handle, int64_t ns) = 0;
     virtual Sensor getSensor() const = 0;
@@ -51,7 +50,6 @@ class HardwareSensor : public SensorInterface
 {
     SensorDevice& mSensorDevice;
     Sensor mSensor;
-    bool mEnabled;
 
 public:
     HardwareSensor(const sensor_t& sensor);
@@ -61,7 +59,6 @@ public:
     virtual bool process(sensors_event_t* outEvent,
             const sensors_event_t& event);
 
-    virtual bool isEnabled() const;
     virtual status_t activate(void* ident, bool enabled);
     virtual status_t setDelay(void* ident, int handle, int64_t ns);
     virtual Sensor getSensor() const;