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104 lines
3.2 KiB
C++
104 lines
3.2 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library - "Jules' Utility Class Extensions"
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Copyright 2004-10 by Raw Material Software Ltd.
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------------------------------------------------------------------------------
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JUCE can be redistributed and/or modified under the terms of the GNU General
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Public License (Version 2), as published by the Free Software Foundation.
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A copy of the license is included in the JUCE distribution, or can be found
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online at www.gnu.org/licenses.
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JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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------------------------------------------------------------------------------
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To release a closed-source product which uses JUCE, commercial licenses are
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available: visit www.rawmaterialsoftware.com/juce for more information.
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==============================================================================
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*/
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#include "../core/juce_StandardHeader.h"
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BEGIN_JUCE_NAMESPACE
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#include "juce_AsyncUpdater.h"
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#include "juce_CallbackMessage.h"
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#include "juce_MessageManager.h"
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//==============================================================================
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class AsyncUpdaterMessage : public CallbackMessage
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{
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public:
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AsyncUpdaterMessage (AsyncUpdater& owner_)
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: owner (owner_)
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{
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}
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void messageCallback()
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{
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if (shouldDeliver.compareAndSetBool (0, 1))
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owner.handleAsyncUpdate();
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}
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Atomic<int> shouldDeliver;
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private:
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AsyncUpdater& owner;
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};
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//==============================================================================
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AsyncUpdater::AsyncUpdater()
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{
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message = new AsyncUpdaterMessage (*this);
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}
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inline Atomic<int>& AsyncUpdater::getDeliveryFlag() const throw()
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{
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return static_cast <AsyncUpdaterMessage*> (message.getObject())->shouldDeliver;
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}
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AsyncUpdater::~AsyncUpdater()
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{
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// You're deleting this object with a background thread while there's an update
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// pending on the main event thread - that's pretty dodgy threading, as the callback could
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// happen after this destructor has finished. You should either use a MessageManagerLock while
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// deleting this object, or find some other way to avoid such a race condition.
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jassert ((! isUpdatePending()) || MessageManager::getInstance()->currentThreadHasLockedMessageManager());
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getDeliveryFlag().set (0);
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}
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void AsyncUpdater::triggerAsyncUpdate()
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{
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if (getDeliveryFlag().compareAndSetBool (1, 0))
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message->post();
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}
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void AsyncUpdater::cancelPendingUpdate() throw()
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{
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getDeliveryFlag().set (0);
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}
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void AsyncUpdater::handleUpdateNowIfNeeded()
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{
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// This can only be called by the event thread.
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jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());
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if (getDeliveryFlag().exchange (0) != 0)
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handleAsyncUpdate();
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}
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bool AsyncUpdater::isUpdatePending() const throw()
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{
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return getDeliveryFlag().value != 0;
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}
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END_JUCE_NAMESPACE
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