rwlock.h

This software aims to create an applet and panel tools to manage a wireless interface card, such as

//
// RWLock.h
//
// $Id: //poco/Main/Foundation/include/Foundation/RWLock.h#5 $
//
// Definition of the RWLock class.
//
// Copyright (c) 2004, Guenter Obiltschnig/Applied Informatics.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
//
// 3. Redistributions in any form must be accompanied by information on
//    how to obtain complete source code for this software and any
//    accompanying software that uses this software.  The source code
//    must either be included in the distribution or be available for no
//    more than the cost of distribution plus a nominal fee, and must be
//    freely redistributable under reasonable conditions.  For an
//    executable file, complete source code means the source code for all
//    modules it contains.  It does not include source code for modules or
//    files that typically accompany the major components of the operating
//    system on which the executable file runs.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//


#ifndef Foundation_RWLock_INCLUDED
#define Foundation_RWLock_INCLUDED


#ifndef Foundation_Foundation_INCLUDED
#include "Foundation/Foundation.h"
#endif
#ifndef Foundation_Exception_INCLUDED
#include "Foundation/Exception.h"
#endif


#if defined(POCO_OS_FAMILY_WINDOWS)
#include "Foundation/RWLock_WIN32.h"
#else
#include "Foundation/RWLock_POSIX.h"
#endif


Foundation_BEGIN


class ScopedRWLock;


class Foundation_API RWLock: private RWLockImp
	/// A reader writer lock allows multiple concurrent
	/// readers or one exclusive writer.
{
public:
	typedef ScopedRWLock ScopedLock;

	RWLock();
		/// Creates the Reader/Writer lock.
		
	~RWLock();
		/// Destroys the Reader/Writer lock.
	
	void readLock();
		/// Acquires a read lock. If another thread currently holds a write lock,
		/// waits until the write lock is released.

	bool tryReadLock();
		/// Tries to acquire a read lock. Immediately returns true if successful, or
		/// false if another thread currently holds a write lock.

	void writeLock();
		/// Acquires a write lock. If one or more other threads currently hold 
		/// locks, waits until all locks are released. The results are undefined
		/// if the same thread already holds a read or write lock

	bool tryWriteLock();
		/// Tries to acquire a write lock. Immediately returns true if successful,
		/// or false if one or more other threads currently hold 
		/// locks. The result is undefined if the same thread already
		/// holds a read or write lock.

	void unlock();
		/// Releases the read or write lock.

private:
	RWLock(const RWLock&);
	RWLock& operator = (const RWLock&);
};


class Foundation_API ScopedRWLock
	/// A variant of ScopedLock for reader/writer locks.
{
public:
	ScopedRWLock(RWLock& rwl, bool write = false);
	~ScopedRWLock();

private:
	RWLock& _rwl;

	ScopedRWLock();
	ScopedRWLock(const ScopedRWLock&);
	ScopedRWLock& operator = (const ScopedRWLock&);
};


//
// inlines
//
inline void RWLock::readLock()
{
	readLockImp();
}


inline bool RWLock::tryReadLock()
{
	return tryReadLockImp();
}


inline void RWLock::writeLock()
{
	writeLockImp();
}


inline bool RWLock::tryWriteLock()
{
	return tryWriteLockImp();
}


inline void RWLock::unlock()
{
	unlockImp();
}


inline ScopedRWLock::ScopedRWLock(RWLock& rwl, bool write): _rwl(rwl)
{
	if (write)
		_rwl.writeLock();
	else
		_rwl.readLock();
}


inline ScopedRWLock::~ScopedRWLock()
{
	_rwl.unlock();
}


Foundation_END


#endif // Foundation_RWLock_INCLUDED