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/*
* Copyright (C) 2015 Intel Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ACQUISITION_THREAD_HPP
#define ACQUISITION_THREAD_HPP
#include <pthread.h>
#include "Sensor.hpp"
class Sensor;
/**
* AcquisitionThread is used for implementing sensors polling
*
* The class creates a thread to periodically poll data from a
* sensor and write it to a pipe. The main thread can use the
* pipe read endpoint to retrieve sensor events.
*
* One can also wake up the thread via the wakeup method after
* changing the sensor parameters.
*
* It includes support for generating a flush complete event.
*/
class AcquisitionThread {
public:
/**
* AcquisitionThread constructor
* @param sensor the sensor to associate with the thread
*/
AcquisitionThread(Sensor *sensor);
/**
* AcquistionThread destructor
*/
~AcquisitionThread();
/**
* Get sensor associated with the thread
* @return the associated sensor
*/
Sensor * getSensor() { return sensor; }
/**
* Get the file descriptor of the pipe read endpoint
* @return the pipe read file descriptor
*/
int getReadPipeFd() { return pipeFds[0]; }
/**
* Get the file descriptor of the pipe write endpoint
* @return the pipe write file descriptor
*/
int getWritePipeFd() { return pipeFds[1]; }
/**
* Initialize the acquisition thread
* @return true if successful, false otherwise
*/
bool init();
/**
* Generate a flush event and send it via the associated pipe
* @return true if successful, false otherwise
*/
bool generateFlushCompleteEvent();
/**
* Wake up thread if it is sleeping
* @return 0 if successful, < 0 otherwise
*/
int wakeup();
private:
static void * acquisitionRoutine(void *param);
int pipeFds[2];
pthread_t pthread;
pthread_condattr_t pthreadCondAttr;
pthread_cond_t pthreadCond;
pthread_mutex_t pthreadMutex;
Sensor *sensor;
bool initialized;
};
#endif // ACQUISITION_THREAD_HPP
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