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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 #define LOG_TAG "Sensors"
     18 
     19 #include <stdint.h>
     20 #include <sys/types.h>
     21 
     22 #include <utils/Errors.h>
     23 #include <utils/RefBase.h>
     24 #include <utils/Looper.h>
     25 
     26 #include <gui/Sensor.h>
     27 #include <gui/SensorChannel.h>
     28 #include <gui/SensorEventQueue.h>
     29 #include <gui/ISensorEventConnection.h>
     30 
     31 #include <android/sensor.h>
     32 
     33 // ----------------------------------------------------------------------------
     34 namespace android {
     35 // ----------------------------------------------------------------------------
     36 
     37 SensorEventQueue::SensorEventQueue(const sp<ISensorEventConnection>& connection)
     38     : mSensorEventConnection(connection)
     39 {
     40 }
     41 
     42 SensorEventQueue::~SensorEventQueue()
     43 {
     44 }
     45 
     46 void SensorEventQueue::onFirstRef()
     47 {
     48     mSensorChannel = mSensorEventConnection->getSensorChannel();
     49 }
     50 
     51 int SensorEventQueue::getFd() const
     52 {
     53     return mSensorChannel->getFd();
     54 }
     55 
     56 ssize_t SensorEventQueue::write(ASensorEvent const* events, size_t numEvents)
     57 {
     58     ssize_t size = mSensorChannel->write(events, numEvents * sizeof(events[0]));
     59     if (size >= 0) {
     60         if (size % sizeof(events[0])) {
     61             // partial write!!! should never happen.
     62             return -EINVAL;
     63         }
     64         // returns number of events written
     65         size /= sizeof(events[0]);
     66     }
     67     return size;
     68 }
     69 
     70 ssize_t SensorEventQueue::read(ASensorEvent* events, size_t numEvents)
     71 {
     72     ssize_t size = mSensorChannel->read(events, numEvents*sizeof(events[0]));
     73     LOGE_IF(size<0 && size!=-EAGAIN,
     74             "SensorChannel::read error (%s)", strerror(-size));
     75     if (size >= 0) {
     76         if (size % sizeof(events[0])) {
     77             // partial read!!! should never happen.
     78             LOGE("SensorEventQueue partial read (event-size=%u, read=%d)",
     79                     sizeof(events[0]), int(size));
     80             return -EINVAL;
     81         }
     82         // returns number of events read
     83         size /= sizeof(events[0]);
     84     }
     85     return size;
     86 }
     87 
     88 sp<Looper> SensorEventQueue::getLooper() const
     89 {
     90     Mutex::Autolock _l(mLock);
     91     if (mLooper == 0) {
     92         mLooper = new Looper(true);
     93         mLooper->addFd(getFd(), getFd(), ALOOPER_EVENT_INPUT, NULL, NULL);
     94     }
     95     return mLooper;
     96 }
     97 
     98 status_t SensorEventQueue::waitForEvent() const
     99 {
    100     const int fd = getFd();
    101     sp<Looper> looper(getLooper());
    102 
    103     int32_t result;
    104     do {
    105         result = looper->pollOnce(-1);
    106         if (result == ALOOPER_EVENT_ERROR) {
    107             LOGE("SensorChannel::waitForEvent error (errno=%d)", errno);
    108             result = -EPIPE; // unknown error, so we make up one
    109             break;
    110         }
    111     } while (result != fd);
    112 
    113     return  (result == fd) ? status_t(NO_ERROR) : result;
    114 }
    115 
    116 status_t SensorEventQueue::wake() const
    117 {
    118     sp<Looper> looper(getLooper());
    119     looper->wake();
    120     return NO_ERROR;
    121 }
    122 
    123 status_t SensorEventQueue::enableSensor(Sensor const* sensor) const {
    124     return mSensorEventConnection->enableDisable(sensor->getHandle(), true);
    125 }
    126 
    127 status_t SensorEventQueue::disableSensor(Sensor const* sensor) const {
    128     return mSensorEventConnection->enableDisable(sensor->getHandle(), false);
    129 }
    130 
    131 status_t SensorEventQueue::enableSensor(int32_t handle, int32_t us) const {
    132     status_t err = mSensorEventConnection->enableDisable(handle, true);
    133     if (err == NO_ERROR) {
    134         mSensorEventConnection->setEventRate(handle, us2ns(us));
    135     }
    136     return err;
    137 }
    138 
    139 status_t SensorEventQueue::disableSensor(int32_t handle) const {
    140     return mSensorEventConnection->enableDisable(handle, false);
    141 }
    142 
    143 status_t SensorEventQueue::setEventRate(Sensor const* sensor, nsecs_t ns) const {
    144     return mSensorEventConnection->setEventRate(sensor->getHandle(), ns);
    145 }
    146 
    147 // ----------------------------------------------------------------------------
    148 }; // namespace android
    149 
    150