453 lines
12 KiB
C++
453 lines
12 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2017 - ROLI Ltd.
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JUCE is an open source library subject to commercial or open-source
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licensing.
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The code included in this file is provided under the terms of the ISC license
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http://www.isc.org/downloads/software-support-policy/isc-license. Permission
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To use, copy, modify, and/or distribute this software for any purpose with or
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without fee is hereby granted provided that the above copyright notice and
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this permission notice appear in all copies.
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JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
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EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
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DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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MessageManager::MessageManager() noexcept
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: messageThreadId (Thread::getCurrentThreadId())
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{
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if (JUCEApplicationBase::isStandaloneApp())
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Thread::setCurrentThreadName ("JUCE Message Thread");
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}
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MessageManager::~MessageManager() noexcept
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{
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broadcaster.reset();
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doPlatformSpecificShutdown();
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jassert (instance == this);
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instance = nullptr; // do this last in case this instance is still needed by doPlatformSpecificShutdown()
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}
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MessageManager* MessageManager::instance = nullptr;
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MessageManager* MessageManager::getInstance()
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{
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if (instance == nullptr)
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{
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instance = new MessageManager();
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doPlatformSpecificInitialisation();
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}
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return instance;
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}
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MessageManager* MessageManager::getInstanceWithoutCreating() noexcept
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{
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return instance;
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}
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void MessageManager::deleteInstance()
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{
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deleteAndZero (instance);
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}
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//==============================================================================
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bool MessageManager::MessageBase::post()
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{
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auto* mm = MessageManager::instance;
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if (mm == nullptr || mm->quitMessagePosted.get() != 0 || ! postMessageToSystemQueue (this))
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{
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Ptr deleter (this); // (this will delete messages that were just created with a 0 ref count)
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return false;
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}
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return true;
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}
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//==============================================================================
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#if JUCE_MODAL_LOOPS_PERMITTED && ! (JUCE_MAC || JUCE_IOS)
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bool MessageManager::runDispatchLoopUntil (int millisecondsToRunFor)
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{
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jassert (isThisTheMessageThread()); // must only be called by the message thread
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auto endTime = Time::currentTimeMillis() + millisecondsToRunFor;
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while (quitMessageReceived.get() == 0)
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{
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JUCE_TRY
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{
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if (! dispatchNextMessageOnSystemQueue (millisecondsToRunFor >= 0))
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Thread::sleep (1);
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}
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JUCE_CATCH_EXCEPTION
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if (millisecondsToRunFor >= 0 && Time::currentTimeMillis() >= endTime)
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break;
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}
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return quitMessageReceived.get() == 0;
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}
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#endif
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#if ! (JUCE_MAC || JUCE_IOS || JUCE_ANDROID)
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class MessageManager::QuitMessage : public MessageManager::MessageBase
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{
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public:
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QuitMessage() {}
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void messageCallback() override
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{
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if (auto* mm = MessageManager::instance)
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mm->quitMessageReceived = true;
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}
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JUCE_DECLARE_NON_COPYABLE (QuitMessage)
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};
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void MessageManager::runDispatchLoop()
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{
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jassert (isThisTheMessageThread()); // must only be called by the message thread
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while (quitMessageReceived.get() == 0)
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{
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JUCE_TRY
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{
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if (! dispatchNextMessageOnSystemQueue (false))
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Thread::sleep (1);
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}
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JUCE_CATCH_EXCEPTION
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}
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}
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void MessageManager::stopDispatchLoop()
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{
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(new QuitMessage())->post();
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quitMessagePosted = true;
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}
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#endif
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//==============================================================================
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class AsyncFunctionCallback : public MessageManager::MessageBase
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{
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public:
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AsyncFunctionCallback (MessageCallbackFunction* const f, void* const param)
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: func (f), parameter (param)
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{}
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void messageCallback() override
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{
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result = (*func) (parameter);
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finished.signal();
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}
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WaitableEvent finished;
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std::atomic<void*> result { nullptr };
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private:
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MessageCallbackFunction* const func;
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void* const parameter;
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JUCE_DECLARE_NON_COPYABLE (AsyncFunctionCallback)
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};
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void* MessageManager::callFunctionOnMessageThread (MessageCallbackFunction* const func, void* const parameter)
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{
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if (isThisTheMessageThread())
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return func (parameter);
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// If this thread has the message manager locked, then this will deadlock!
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jassert (! currentThreadHasLockedMessageManager());
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const ReferenceCountedObjectPtr<AsyncFunctionCallback> message (new AsyncFunctionCallback (func, parameter));
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if (message->post())
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{
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message->finished.wait();
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return message->result.load();
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}
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jassertfalse; // the OS message queue failed to send the message!
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return nullptr;
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}
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//==============================================================================
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void MessageManager::deliverBroadcastMessage (const String& value)
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{
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if (broadcaster != nullptr)
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broadcaster->sendActionMessage (value);
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}
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void MessageManager::registerBroadcastListener (ActionListener* const listener)
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{
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if (broadcaster == nullptr)
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broadcaster.reset (new ActionBroadcaster());
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broadcaster->addActionListener (listener);
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}
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void MessageManager::deregisterBroadcastListener (ActionListener* const listener)
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{
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if (broadcaster != nullptr)
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broadcaster->removeActionListener (listener);
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}
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//==============================================================================
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bool MessageManager::isThisTheMessageThread() const noexcept
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{
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return Thread::getCurrentThreadId() == messageThreadId;
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}
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void MessageManager::setCurrentThreadAsMessageThread()
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{
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auto thisThread = Thread::getCurrentThreadId();
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if (messageThreadId != thisThread)
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{
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messageThreadId = thisThread;
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// This is needed on windows to make sure the message window is created by this thread
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doPlatformSpecificShutdown();
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doPlatformSpecificInitialisation();
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}
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}
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bool MessageManager::currentThreadHasLockedMessageManager() const noexcept
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{
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auto thisThread = Thread::getCurrentThreadId();
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return thisThread == messageThreadId || thisThread == threadWithLock.get();
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}
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//==============================================================================
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//==============================================================================
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/* The only safe way to lock the message thread while another thread does
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some work is by posting a special message, whose purpose is to tie up the event
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loop until the other thread has finished its business.
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Any other approach can get horribly deadlocked if the OS uses its own hidden locks which
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get locked before making an event callback, because if the same OS lock gets indirectly
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accessed from another thread inside a MM lock, you're screwed. (this is exactly what happens
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in Cocoa).
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*/
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struct MessageManager::Lock::BlockingMessage : public MessageManager::MessageBase
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{
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BlockingMessage (const MessageManager::Lock* parent) noexcept
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// need a const_cast here as VS2013 doesn't like a const pointer to be in an atomic
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: owner (const_cast<MessageManager::Lock*> (parent)) {}
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void messageCallback() override
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{
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{
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ScopedLock lock (ownerCriticalSection);
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if (auto* o = owner.get())
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o->messageCallback();
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}
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releaseEvent.wait();
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}
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CriticalSection ownerCriticalSection;
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Atomic<MessageManager::Lock*> owner;
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WaitableEvent releaseEvent;
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JUCE_DECLARE_NON_COPYABLE (BlockingMessage)
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};
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//==============================================================================
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MessageManager::Lock::Lock() {}
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MessageManager::Lock::~Lock() { exit(); }
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void MessageManager::Lock::enter() const noexcept { tryAcquire (true); }
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bool MessageManager::Lock::tryEnter() const noexcept { return tryAcquire (false); }
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bool MessageManager::Lock::tryAcquire (bool lockIsMandatory) const noexcept
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{
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auto* mm = MessageManager::instance;
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if (mm == nullptr)
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{
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jassertfalse;
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return false;
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}
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if (! lockIsMandatory && (abortWait.get() != 0))
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{
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abortWait.set (0);
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return false;
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}
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if (mm->currentThreadHasLockedMessageManager())
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return true;
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try
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{
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blockingMessage = new BlockingMessage (this);
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}
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catch (...)
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{
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jassert (! lockIsMandatory);
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return false;
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}
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if (! blockingMessage->post())
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{
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// post of message failed while trying to get the lock
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jassert (! lockIsMandatory);
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blockingMessage = nullptr;
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return false;
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}
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do
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{
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while (abortWait.get() == 0)
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lockedEvent.wait (-1);
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abortWait.set (0);
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if (lockGained.get() != 0)
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{
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mm->threadWithLock = Thread::getCurrentThreadId();
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return true;
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}
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} while (lockIsMandatory);
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// we didn't get the lock
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blockingMessage->releaseEvent.signal();
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{
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ScopedLock lock (blockingMessage->ownerCriticalSection);
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lockGained.set (0);
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blockingMessage->owner.set (nullptr);
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}
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blockingMessage = nullptr;
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return false;
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}
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void MessageManager::Lock::exit() const noexcept
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{
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if (lockGained.compareAndSetBool (false, true))
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{
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auto* mm = MessageManager::instance;
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jassert (mm == nullptr || mm->currentThreadHasLockedMessageManager());
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lockGained.set (0);
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if (mm != nullptr)
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mm->threadWithLock = 0;
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if (blockingMessage != nullptr)
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{
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blockingMessage->releaseEvent.signal();
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blockingMessage = nullptr;
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}
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}
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}
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void MessageManager::Lock::messageCallback() const
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{
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lockGained.set (1);
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abort();
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}
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void MessageManager::Lock::abort() const noexcept
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{
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abortWait.set (1);
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lockedEvent.signal();
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}
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//==============================================================================
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MessageManagerLock::MessageManagerLock (Thread* threadToCheck)
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: locked (attemptLock (threadToCheck, nullptr))
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{}
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MessageManagerLock::MessageManagerLock (ThreadPoolJob* jobToCheck)
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: locked (attemptLock (nullptr, jobToCheck))
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{}
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bool MessageManagerLock::attemptLock (Thread* threadToCheck, ThreadPoolJob* jobToCheck)
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{
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jassert (threadToCheck == nullptr || jobToCheck == nullptr);
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if (threadToCheck != nullptr)
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threadToCheck->addListener (this);
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if (jobToCheck != nullptr)
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jobToCheck->addListener (this);
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// tryEnter may have a spurious abort (return false) so keep checking the condition
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while ((threadToCheck == nullptr || ! threadToCheck->threadShouldExit())
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&& (jobToCheck == nullptr || ! jobToCheck->shouldExit()))
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{
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if (mmLock.tryEnter())
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break;
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}
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if (threadToCheck != nullptr)
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{
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threadToCheck->removeListener (this);
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if (threadToCheck->threadShouldExit())
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return false;
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}
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if (jobToCheck != nullptr)
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{
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jobToCheck->removeListener (this);
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if (jobToCheck->shouldExit())
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return false;
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}
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return true;
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}
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MessageManagerLock::~MessageManagerLock() noexcept { mmLock.exit(); }
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void MessageManagerLock::exitSignalSent()
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{
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mmLock.abort();
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}
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//==============================================================================
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JUCE_API void JUCE_CALLTYPE initialiseJuce_GUI();
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JUCE_API void JUCE_CALLTYPE initialiseJuce_GUI()
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{
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JUCE_AUTORELEASEPOOL
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{
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MessageManager::getInstance();
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}
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}
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JUCE_API void JUCE_CALLTYPE shutdownJuce_GUI();
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JUCE_API void JUCE_CALLTYPE shutdownJuce_GUI()
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{
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JUCE_AUTORELEASEPOOL
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{
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DeletedAtShutdown::deleteAll();
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MessageManager::deleteInstance();
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}
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}
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static int numScopedInitInstances = 0;
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ScopedJuceInitialiser_GUI::ScopedJuceInitialiser_GUI() { if (numScopedInitInstances++ == 0) initialiseJuce_GUI(); }
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ScopedJuceInitialiser_GUI::~ScopedJuceInitialiser_GUI() { if (--numScopedInitInstances == 0) shutdownJuce_GUI(); }
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} // namespace juce
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