JUCE/modules/juce_events/broadcasters/juce_ChangeBroadcaster.cpp

/*
  ==============================================================================

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

  ==============================================================================
*/

BEGIN_JUCE_NAMESPACE

//==============================================================================
ChangeBroadcaster::ChangeBroadcaster() noexcept
{
    // are you trying to create this object before or after juce has been intialised??
    jassert (MessageManager::instance != nullptr);

    callback.owner = this;
}

ChangeBroadcaster::~ChangeBroadcaster()
{
    // all event-based objects must be deleted BEFORE juce is shut down!
    jassert (MessageManager::instance != nullptr);
}

void ChangeBroadcaster::addChangeListener (ChangeListener* const listener)
{
    // Listeners can only be safely added when the event thread is locked
    // You can  use a MessageManagerLock if you need to call this from another thread.
    jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());

    changeListeners.add (listener);
}

void ChangeBroadcaster::removeChangeListener (ChangeListener* const listener)
{
    // Listeners can only be safely added when the event thread is locked
    // You can  use a MessageManagerLock if you need to call this from another thread.
    jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());

    changeListeners.remove (listener);
}

void ChangeBroadcaster::removeAllChangeListeners()
{
    // Listeners can only be safely added when the event thread is locked
    // You can  use a MessageManagerLock if you need to call this from another thread.
    jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());

    changeListeners.clear();
}

void ChangeBroadcaster::sendChangeMessage()
{
    if (changeListeners.size() > 0)
        callback.triggerAsyncUpdate();
}

void ChangeBroadcaster::sendSynchronousChangeMessage()
{
    // This can only be called by the event thread.
    jassert (MessageManager::getInstance()->isThisTheMessageThread());

    callback.cancelPendingUpdate();
    callListeners();
}

void ChangeBroadcaster::dispatchPendingMessages()
{
    callback.handleUpdateNowIfNeeded();
}

void ChangeBroadcaster::callListeners()
{
    changeListeners.call (&ChangeListener::changeListenerCallback, this);
}

//==============================================================================
ChangeBroadcaster::ChangeBroadcasterCallback::ChangeBroadcasterCallback()
    : owner (nullptr)
{
}

void ChangeBroadcaster::ChangeBroadcasterCallback::handleAsyncUpdate()
{
    jassert (owner != nullptr);
    owner->callListeners();
}


END_JUCE_NAMESPACE