topical media & game development
lib-of-vs-libs-Poco-include-Poco-Condition.h / h
//
// Condition.h
//
//
//
// Library: Foundation
// Package: Threading
// Module: Condition
//
// Definition of the Condition class template.
//
// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
ifndef Foundation_Condition_INCLUDED
define Foundation_Condition_INCLUDED
include "Poco/Foundation.h"
include "Poco/Mutex.h"
include "Poco/ScopedUnlock.h"
include "Poco/Event.h"
include "Poco/Exception.h"
include <deque>
namespace Poco {
class Foundation_API Condition
A Condition is a synchronization object used to block a thread
until a particular condition is met.
A Condition object is always used in conjunction with
a Mutex (or FastMutex) object.
Condition objects are similar to POSIX condition variables, which the
difference that Condition is not subject to spurious wakeups.
Threads waiting on a Condition are resumed in FIFO order.
{
public:
Condition();
Creates the Condition.
~Condition();
Destroys the Condition.
template
<class Mtx>
void wait(Mtx& mutex)
Unlocks the mutex (which must be locked upon calling
wait()) and waits until the Condition is signalled.
The given mutex will be locked again upon
leaving the function, even in case of an exception.
{
ScopedUnlock<Mtx> unlock(mutex, false);
Event event;
{
FastMutex::ScopedLock lock(_mutex);
mutex.unlock();
enqueue(event);
}
event.wait();
}
template
<class Mtx>
void wait(Mtx& mutex, long milliseconds)
Unlocks the mutex (which must be locked upon calling
wait()) and waits for the given time until the Condition is signalled.
The given mutex will be locked again upon successfully leaving the
function, even in case of an exception.
Throws a TimeoutException if the Condition is not signalled
within the given time interval.
{
if (!tryWait(mutex, milliseconds))
throw TimeoutException();
}
template
<class Mtx>
bool tryWait(Mtx& mutex, long milliseconds)
Unlocks the mutex (which must be locked upon calling
tryWait()) and waits for the given time until the Condition is signalled.
The given mutex will be locked again upon leaving the
function, even in case of an exception.
Returns true if the Condition has been signalled
within the given time interval, otherwise false.
{
ScopedUnlock<Mtx> unlock(mutex, false);
Event event;
{
FastMutex::ScopedLock lock(_mutex);
mutex.unlock();
enqueue(event);
}
if (!event.tryWait(milliseconds))
{
FastMutex::ScopedLock lock(_mutex);
dequeue(event);
return false;
}
return true;
}
void signal();
Signals the Condition and allows one waiting thread
to continue execution.
void broadcast();
Signals the Condition and allows all waiting
threads to continue their execution.
protected:
void enqueue(Event& event);
void dequeue();
void dequeue(Event& event);
private:
Condition(const Condition&);
Condition& operator = (const Condition&);
typedef std::deque<Event*> WaitQueue;
FastMutex _mutex;
WaitQueue _waitQueue;
};
} // namespace Poco
endif // Foundation_Condition_INCLUDED
(C) Æliens
04/09/2009
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