AOO410/main/salhelper/inc/salhelper/futurequeue.hxx

/**************************************************************
 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 * 
 *************************************************************/



#ifndef _SALHELPER_FUTUREQUEUE_HXX_
#define _SALHELPER_FUTUREQUEUE_HXX_

#include <sal/types.h>
#include <rtl/ref.hxx>
#include <osl/mutex.hxx>
#include <salhelper/future.hxx>
#include <salhelper/queue.hxx>

namespace salhelper
{

//----------------------------------------------------------------------------

#ifndef SALHELPER_COPYCTOR_API
#define SALHELPER_COPYCTOR_API(C) C (const C&); C& operator= (const C&)
#endif

//----------------------------------------------------------------------------

template<class element_type>
class FutureQueue : protected osl::Mutex
{
	/** Representation.
	 */
	typedef salhelper::Future<element_type> future_type;

	salhelper::QueueBase< rtl::Reference<future_type> > m_aDelayed;
	salhelper::QueueBase< rtl::Reference<future_type> > m_aPresent;

	/** Not implemented.
	 */
	SALHELPER_COPYCTOR_API(FutureQueue<element_type>);

public:
	/** Construction.
	 */
	inline FutureQueue()
	{}

	/** Destruction.
	 */
	inline ~FutureQueue()
	{}

	/** Enqueue element at queue tail.
	 */
	inline void put (const element_type& element)
	{
		osl::MutexGuard aGuard (*this);

		rtl::Reference<future_type> xFuture (m_aDelayed.get());
		if (!xFuture.is())
		{
			xFuture = new future_type();
			m_aPresent.put (xFuture);
		}
		xFuture->set (element);
	}

	/** Dequeue a future to element at queue head.
	 */
	inline rtl::Reference< salhelper::Future<element_type> > get()
	{
		osl::MutexGuard aGuard (*this);

		rtl::Reference<future_type> xFuture (m_aPresent.get());
		if (!xFuture.is())
		{
			xFuture = new future_type();
			m_aDelayed.put (xFuture);
		}
		return (xFuture);
	}
};

//----------------------------------------------------------------------------

} // namespace salhelper

#endif /* !_SALHELPER_FUTUREQUEUE */