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/*
* ZeroTier One - Global Peer to Peer Ethernet
* Copyright (C) 2011-2015 ZeroTier Networks LLC
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* --
*
* ZeroTier may be used and distributed under the terms of the GPLv3, which
* are available at: http://www.gnu.org/licenses/gpl-3.0.html
*
* If you would like to embed ZeroTier into a commercial application or
* redistribute it in a modified binary form, please contact ZeroTier Networks
* LLC. Start here: http://www.zerotier.com/
*/
#ifndef ZT_MTQ_HPP
#define ZT_MTQ_HPP
#include <stdlib.h>
#include <stdint.h>
#include <queue>
#include "../node/Constants.hpp"
#include "../node/NonCopyable.hpp"
#include "../node/Utils.hpp"
#ifdef __WINDOWS__
#include <Windows.h>
#else
#include <time.h>
#include <pthread.h>
#endif
namespace ZeroTier {
/**
* A synchronized multithreaded FIFO queue
*
* This is designed for a use case where one thread pushes, the
* other pops.
*/
template<typename T>
class MTQ : NonCopyable
{
public:
MTQ()
{
#ifdef __WINDOWS__
_sem = CreateSemaphore(NULL,0,0x7fffffff,NULL);
InitializeCriticalSection(&_cs);
#else
pthread_mutex_init(&_mh,(const pthread_mutexattr_t *)0);
pthread_cond_init(&_cond,(const pthread_condattr_t *)0);
#endif
}
~MTQ()
{
#ifdef __WINDOWS__
CloseHandle(_sem);
DeleteCriticalSection(&_cs);
#else
pthread_cond_destroy(&_cond);
pthread_mutex_destroy(&_mh);
#endif
}
/**
* Push something onto the end of the FIFO and signal waiting thread(s)
*
* @param v Value to push
*/
inline void push(const T &v)
{
#ifdef __WINDOWS__
EnterCriticalSection(&_cs);
try {
_q.push(v);
LeaveCriticalSection(&_cs);
ReleaseSemaphore(_sem,1,NULL);
} catch ( ... ) {
LeaveCriticalSection(&_cs);
throw;
}
#else
pthread_mutex_lock(const_cast <pthread_mutex_t *>(&_mh));
try {
_q.push(v);
pthread_mutex_unlock(const_cast <pthread_mutex_t *>(&_mh));
pthread_cond_signal(const_cast <pthread_cond_t *>(&_cond));
} catch ( ... ) {
pthread_mutex_unlock(const_cast <pthread_mutex_t *>(&_mh));
throw;
}
#endif
}
/**
* Pop fron queue with optional timeout
*
* @param v Result parameter to set to next value
* @param ms Milliseconds timeout or 0 for none
* @return True if v was set to something, false on timeout
*/
inline bool pop(T &v,unsigned long ms = 0)
{
#ifdef __WINDOWS__
if (ms > 0)
WaitForSingleObject(_sem,(DWORD)ms);
else WaitForSingleObject(_sem,INFINITE);
EnterCriticalSection(&_cs);
try {
if (_q.empty()) {
LeaveCriticalSection(&_cs);
return false;
} else {
v = _q.front();
_q.pop();
LeaveCriticalSection(&_cs);
return true;
}
} catch ( ... ) {
LeaveCriticalSection(&_cs);
throw;
}
#else
pthread_mutex_lock(const_cast <pthread_mutex_t *>(&_mh));
try {
if (_q.empty()) {
if (ms > 0) {
uint64_t when = Utils::now() + (uint64_t)ms;
struct timespec ts;
ts.tv_sec = (unsigned long)(when / 1000);
ts.tv_nsec = (unsigned long)(when % 1000) * (unsigned long)1000000;
pthread_cond_timedwait(const_cast <pthread_cond_t *>(&_cond),const_cast <pthread_mutex_t *>(&_mh),&ts);
} else {
pthread_cond_wait(const_cast <pthread_cond_t *>(&_cond),const_cast <pthread_mutex_t *>(&_mh));
}
if (_q.empty()) {
pthread_mutex_unlock(const_cast <pthread_mutex_t *>(&_mh));
return false;
}
}
v = _q.front();
_q.pop();
pthread_mutex_unlock(const_cast <pthread_mutex_t *>(&_mh));
return true;
} catch ( ... ) {
pthread_mutex_unlock(const_cast <pthread_mutex_t *>(&_mh));
throw;
}
#endif
}
private:
std::queue<T> _q;
#ifdef __WINDOWS__
HANDLE _sem;
CRITICAL_SECTION _cs;
#else
pthread_cond_t _cond;
pthread_mutex_t _mh;
#endif
};
} // namespace ZeroTier
#endif
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