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/*
Title: Mutex and Condition Variable library.
Copyright (c) 2007 David C. J. Matthews
Portions of this code are derived from the original stream io
package copyright CUTS 1983-2000.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef LOCKING_H_DEFINED
#define LOCKING_H_DEFINED
#ifdef WIN32
#include "winconfig.h"
#else
#include "config.h"
#endif
#ifdef HAVE_WINDOWS_H
#include <windows.h>
#endif
#ifdef HAVE_PTHREAD_H
#include <pthread.h>
#endif
// Simple Mutex.
class PLock {
public:
PLock();
~PLock();
void Lock(void); // Lock the mutex
void Unlock(void); // Unlock the mutex
bool Trylock(void); // Try to lock the mutex - returns true if succeeded
private:
#if (defined(HAVE_LIBPTHREAD) && defined(HAVE_PTHREAD_H))
pthread_mutex_t lock;
#elif defined(HAVE_WINDOWS_H)
CRITICAL_SECTION lock;
#endif
friend class PCondVar;
};
// Lock a mutex and automatically unlock it in the destructor.
// This can be used in a function to lock a mutex and unlock it
// when the function either returns normally or raises an exception.
class PLocker {
public:
PLocker(PLock *lock): m_lock(lock) { m_lock->Lock(); }
~PLocker() { m_lock->Unlock(); }
private:
PLock *m_lock;
};
// Simple condition variable. N.B. The Windows code does not
// support multiple threads blocking on this condition variable.
class PCondVar {
public:
PCondVar();
~PCondVar();
void Wait(PLock *pLock); // Wait indefinitely. Drops the lock and reaquires it.
// Wait for a signal or until the time. The argument is an absolute time
// represented as a struct timespec in Unix and a FILETIME in Windows.
void WaitUntil(PLock *pLock, const void *timeArg);
// Wait for a time. This is used internally in the RTS.
bool WaitFor(PLock *pLock, unsigned milliseconds);
void Signal(void); // Wake up the waiting thread.
private:
#if (defined(HAVE_LIBPTHREAD) && defined(HAVE_PTHREAD_H))
pthread_cond_t cond;
pthread_mutex_t *plock;
#elif defined(HAVE_WINDOWS_H)
HANDLE cond;
CRITICAL_SECTION *plock;
#endif
};
#endif
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