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/*
* Copyright (C) 2012 The Android Open Source Project
*
* 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.
*/
/*
* Encapsulate a condition variable for thread synchronization.
*/
#include "CondVar.h"
#include "NfcJniUtil.h"
#include <errno.h>
/*******************************************************************************
**
** Function: CondVar
**
** Description: Initialize member variables.
**
** Returns: None.
**
*******************************************************************************/
CondVar::CondVar ()
{
memset (&mCondition, 0, sizeof(mCondition));
int const res = pthread_cond_init (&mCondition, NULL);
if (res)
{
ALOGE ("CondVar::CondVar: fail init; error=0x%X", res);
}
}
/*******************************************************************************
**
** Function: ~CondVar
**
** Description: Cleanup all resources.
**
** Returns: None.
**
*******************************************************************************/
CondVar::~CondVar ()
{
int const res = pthread_cond_destroy (&mCondition);
if (res)
{
ALOGE ("CondVar::~CondVar: fail destroy; error=0x%X", res);
}
}
/*******************************************************************************
**
** Function: wait
**
** Description: Block the caller and wait for a condition.
**
** Returns: None.
**
*******************************************************************************/
void CondVar::wait (Mutex& mutex)
{
int const res = pthread_cond_wait (&mCondition, mutex.nativeHandle());
if (res)
{
ALOGE ("CondVar::wait: fail wait; error=0x%X", res);
}
}
/*******************************************************************************
**
** Function: wait
**
** Description: Block the caller and wait for a condition.
** millisec: Timeout in milliseconds.
**
** Returns: True if wait is successful; false if timeout occurs.
**
*******************************************************************************/
bool CondVar::wait (Mutex& mutex, long millisec)
{
bool retVal = false;
struct timespec absoluteTime;
if (clock_gettime (CLOCK_MONOTONIC, &absoluteTime) == -1)
{
ALOGE ("CondVar::wait: fail get time; errno=0x%X", errno);
}
else
{
absoluteTime.tv_sec += millisec / 1000;
long ns = absoluteTime.tv_nsec + ((millisec % 1000) * 1000000);
if (ns > 1000000000)
{
absoluteTime.tv_sec++;
absoluteTime.tv_nsec = ns - 1000000000;
}
else
absoluteTime.tv_nsec = ns;
}
//pthread_cond_timedwait_monotonic_np() is an Android-specific function
//declared in /development/ndk/platforms/android-9/include/pthread.h;
//it uses monotonic clock.
//the standard pthread_cond_timedwait() uses realtime clock.
int waitResult = pthread_cond_timedwait_monotonic_np (&mCondition, mutex.nativeHandle(), &absoluteTime);
if ((waitResult != 0) && (waitResult != ETIMEDOUT))
ALOGE ("CondVar::wait: fail timed wait; error=0x%X", waitResult);
retVal = (waitResult == 0); //waited successfully
return retVal;
}
/*******************************************************************************
**
** Function: notifyOne
**
** Description: Unblock the waiting thread.
**
** Returns: None.
**
*******************************************************************************/
void CondVar::notifyOne ()
{
int const res = pthread_cond_signal (&mCondition);
if (res)
{
ALOGE ("CondVar::notifyOne: fail signal; error=0x%X", res);
}
}
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