/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

* 

* Description:

*    This file contains headers of SafeQueue template class.

*/

#ifndef SAFEQUEUE_H

#define SAFEQUEUE_H

#include "sync.h"

//STL

#pragma warning (push, 3)

#pragma warning( disable : 4702 ) // Unreachable code warning

#pragma warning( disable : 4290 ) // C++ exception specification ignored except to indicate a function is not __declspec(nothrow)

#include <queue>

using namespace std;

//**********************************************************************************

// Template Class SafeQueue

// 

// This template class implements a thread safe queue with generic types

//**********************************************************************************

template <class T>

class SafeQueue : private queue<T>,

				  private Mutex,

				  private Semaphore

{

public:

    typedef typename queue<T>::size_type size_type;

    SafeQueue();

	~SafeQueue();

	/*

	 * Adds a new element to the end of the queue

	 */

	void push(const T& val);

	/*

	 * Removes the next element in the queue

	 */

	void pop(void);

	/*

	 * Returns whether the queue is empty or not

	 */

	bool empty(void) const;

	/*

	 * Returns a reference to the last element in the queue

	 */

	T& back(DWORD timeout = INFINITE) throw (TimeoutException);

	/*

	 * Returns a constant reference to the last element in the queue

	 */

	const T& back(DWORD timeout = INFINITE) const throw (TimeoutException);

	/*

	 * Returns a reference to the next element in the queue

	 */

	T& front(DWORD timeout = INFINITE) throw (TimeoutException);

	/*

	 * Returns a constant reference to the next element in the queue

	 */

	const T& front(DWORD timeout = INFINITE) const throw (TimeoutException);

	/*

	 * Returns the number of elements in the queue

	 */

	typename SafeQueue<T>::size_type size(void) const;

	/*

	 * This method is used to pop all of the elements in queue and return them in single Data object

	 */

	T& popAll(DWORD timeout = INFINITE) throw (TimeoutException);

};

template <class T>

SafeQueue<T>::SafeQueue()

{

}

template <class T>

SafeQueue<T>::~SafeQueue()

{

}

/*

 * Adds a new element to the end of the queue

 */

template <class T>

void SafeQueue<T>::push(const T& val)

{

	Mutex::Lock();

	queue<T>::push(val);

	Mutex::Unlock();

	Semaphore::Notify();

}

/*

 * Removes the next element in the queue

 */

template <class T>

void SafeQueue<T>::pop(void)

{

	Mutex::Lock();

	queue<T>::pop();

	Mutex::Unlock();

}

/*

 * Returns whether the queue is empty or not

 */

template <class T>

bool SafeQueue<T>::empty(void) const

{

	const_cast<SafeQueue<T>*>(this)->Lock();

	bool value = queue<T>::empty();

	const_cast<SafeQueue<T>*>(this)->Unlock();

	return value;

}

/*

 * Returns a reference to the last element in the queue

 */

template <class T>

T& SafeQueue<T>::back(DWORD timeout)

	throw (TimeoutException)

{

	if (Semaphore::Wait(timeout) == WAIT_TIMEOUT)

	{

		throw TimeoutException("queue back timed out");

	}

	Mutex::Lock();

	T& value = queue<T>::back();

	Mutex::Unlock();

	return value;

}

/*

 * Returns a constant reference to the last element in the queue

 */

template <class T>

const T& SafeQueue<T>::back(DWORD timeout) const

	throw (TimeoutException)

{

	if (const_cast<SafeQueue<T>*>(this)->Wait(timeout) == WAIT_TIMEOUT)

	{

		throw TimeoutException("queue back timed out");;

	}

	const_cast<SafeQueue<T>*>(this)->Lock();

	const T& value = queue<T>::back();

	const_cast<SafeQueue<T>*>(this)->Unlock();

	return value;

}

/*

 * Returns a reference to the next element in the queue

 */

template <class T>

T& SafeQueue<T>::front(DWORD timeout)

	throw (TimeoutException)

{

	if (Semaphore::Wait(timeout) == WAIT_TIMEOUT)

	{

		throw TimeoutException("queue front timed out");

	}

	Mutex::Lock();

	T& value = queue<T>::front();

	Mutex::Unlock();

	return value;

}

/*

 * Returns a constant reference to the next element in the queue

 */

template <class T>

const T& SafeQueue<T>::front(DWORD timeout) const

	throw (TimeoutException)

{

	if (const_cast<SafeQueue<T>*>(this)->Wait(timeout) == WAIT_TIMEOUT)

	{

		throw TimeoutException("queue front timed out");

	}

	const_cast<SafeQueue<T>*>(this)->Lock();

	const T& value = queue<T>::front();

	const_cast<SafeQueue<T>*>(this)->Unlock();

	return value;

}

/*

 * Returns the number of elements in the queue

 */

template <class T>

typename SafeQueue<T>::size_type SafeQueue<T>::size(void) const

{

	const_cast<SafeQueue<T>*>(this)->Lock();

	queue<T>::size_type value = queue<T>::size();

	const_cast<SafeQueue<T>*>(this)->Unlock();

	return value;

}

#pragma warning (pop)

#endif

// End of the file