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/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qtconcurrentexception.h"
#ifndef QT_NO_QFUTURE
#ifndef QT_NO_EXCEPTIONS
QT_BEGIN_NAMESPACE
/*!
\class QtConcurrent::Exception
\brief The Exception class provides a base class for exceptions that can transferred across threads.
\since 4.4
Qt Concurrent supports throwing and catching exceptions across thread
boundaries, provided that the exception inherit from QtConcurrent::Exception
and implement two helper functions:
\snippet doc/src/snippets/code/src_corelib_concurrent_qtconcurrentexception.cpp 0
QtConcurrent::Exception subclasses must be thrown by value and
caught by reference:
\snippet doc/src/snippets/code/src_corelib_concurrent_qtconcurrentexception.cpp 1
If you throw an exception that is not a subclass of QtConcurrent::Exception,
the Qt Concurrent functions will throw a QtConcurrent::UnhandledException
in the receiver thread.
When using QFuture, transferred exceptions will be thrown when calling the following functions:
\list
\o QFuture::waitForFinished()
\o QFuture::result()
\o QFuture::resultAt()
\o QFuture::results()
\endlist
*/
/*!
\fn QtConcurrent::Exception::raise() const
In your QtConcurrent::Exception subclass, reimplement raise() like this:
\snippet doc/src/snippets/code/src_corelib_concurrent_qtconcurrentexception.cpp 2
*/
/*!
\fn QtConcurrent::Exception::clone() const
In your QtConcurrent::Exception subclass, reimplement clone() like this:
\snippet doc/src/snippets/code/src_corelib_concurrent_qtconcurrentexception.cpp 3
*/
/*!
\class QtConcurrent::UnhandledException
\brief The UnhandledException class represents an unhandled exception in a worker thread.
\since 4.4
If a worker thread throws an exception that is not a subclass of QtConcurrent::Exception,
the Qt Concurrent functions will throw a QtConcurrent::UnhandledException
on the receiver thread side.
Inheriting from this class is not supported.
*/
/*!
\fn QtConcurrent::UnhandledException::raise() const
\internal
*/
/*!
\fn QtConcurrent::UnhandledException::clone() const
\internal
*/
namespace QtConcurrent
{
void Exception::raise() const
{
Exception e = *this;
throw e;
}
Exception *Exception::clone() const
{
return new Exception(*this);
}
void UnhandledException::raise() const
{
UnhandledException e = *this;
throw e;
}
Exception *UnhandledException::clone() const
{
return new UnhandledException(*this);
}
#ifndef qdoc
namespace internal {
class Base
{
public:
Base(Exception *exception)
: exception(exception), refCount(1), hasThrown(false) { }
~Base() { delete exception; }
Exception *exception;
QAtomicInt refCount;
bool hasThrown;
};
ExceptionHolder::ExceptionHolder(Exception *exception)
: base(new Base(exception)) {}
ExceptionHolder::ExceptionHolder(const ExceptionHolder &other)
: base(other.base)
{
base->refCount.ref();
}
void ExceptionHolder::operator=(const ExceptionHolder &other)
{
if (base == other.base)
return;
if (base->refCount.deref() == false)
delete base;
base = other.base;
base->refCount.ref();
}
ExceptionHolder::~ExceptionHolder()
{
if (base->refCount.deref() == 0)
delete base;
}
Exception *ExceptionHolder::exception() const
{
return base->exception;
}
void ExceptionStore::setException(const Exception &e)
{
if (hasException() == false)
exceptionHolder = ExceptionHolder(e.clone());
}
bool ExceptionStore::hasException() const
{
return (exceptionHolder.exception() != 0);
}
ExceptionHolder ExceptionStore::exception()
{
return exceptionHolder;
}
void ExceptionStore::throwPossibleException()
{
if (hasException() ) {
exceptionHolder.base->hasThrown = true;
exceptionHolder.exception()->raise();
}
}
bool ExceptionStore::hasThrown() const { return exceptionHolder.base->hasThrown; }
} // namespace internal
#endif //qdoc
} // namespace QtConcurrent
QT_END_NAMESPACE
#endif // QT_NO_EXCEPTIONS
#endif // QT_NO_CONCURRENT
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