juce/source/src/events/juce_ChangeBroadcaster.cpp

   1 /*
   2   ==============================================================================
   3
   4    This file is part of the JUCE library - "Jules' Utility Class Extensions"
   5    Copyright 2004-11 by Raw Material Software Ltd.
   6
   7   ------------------------------------------------------------------------------
   8
   9    JUCE can be redistributed and/or modified under the terms of the GNU General
  10    Public License (Version 2), as published by the Free Software Foundation.
  11    A copy of the license is included in the JUCE distribution, or can be found
  12    online at www.gnu.org/licenses.
  13
  14    JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
  15    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  16    A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
  17
  18   ------------------------------------------------------------------------------
  19
  20    To release a closed-source product which uses JUCE, commercial licenses are
  21    available: visit www.rawmaterialsoftware.com/juce for more information.
  22
  23   ==============================================================================
  24 */
  25
  26 #include "../core/juce_StandardHeader.h"
  27
  28 BEGIN_JUCE_NAMESPACE
  29
  30 #include "juce_ChangeBroadcaster.h"
  31 #include "juce_MessageManager.h"
  32
  33
  34 //==============================================================================
  35 ChangeBroadcaster::ChangeBroadcaster() noexcept
  36 {
  37     // are you trying to create this object before or after juce has been intialised??
  38     jassert (MessageManager::instance != nullptr);
  39
  40     callback.owner = this;
  41 }
  42
  43 ChangeBroadcaster::~ChangeBroadcaster()
  44 {
  45     // all event-based objects must be deleted BEFORE juce is shut down!
  46     jassert (MessageManager::instance != nullptr);
  47 }
  48
  49 void ChangeBroadcaster::addChangeListener (ChangeListener* const listener)
  50 {
  51     // Listeners can only be safely added when the event thread is locked
  52     // You can  use a MessageManagerLock if you need to call this from another thread.
  53     jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());
  54
  55     changeListeners.add (listener);
  56 }
  57
  58 void ChangeBroadcaster::removeChangeListener (ChangeListener* const listener)
  59 {
  60     // Listeners can only be safely added when the event thread is locked
  61     // You can  use a MessageManagerLock if you need to call this from another thread.
  62     jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());
  63
  64     changeListeners.remove (listener);
  65 }
  66
  67 void ChangeBroadcaster::removeAllChangeListeners()
  68 {
  69     // Listeners can only be safely added when the event thread is locked
  70     // You can  use a MessageManagerLock if you need to call this from another thread.
  71     jassert (MessageManager::getInstance()->currentThreadHasLockedMessageManager());
  72
  73     changeListeners.clear();
  74 }
  75
  76 void ChangeBroadcaster::sendChangeMessage()
  77 {
  78     if (changeListeners.size() > 0)
  79         callback.triggerAsyncUpdate();
  80 }
  81
  82 void ChangeBroadcaster::sendSynchronousChangeMessage()
  83 {
  84     // This can only be called by the event thread.
  85     jassert (MessageManager::getInstance()->isThisTheMessageThread());
  86
  87     callback.cancelPendingUpdate();
  88     callListeners();
  89 }
  90
  91 void ChangeBroadcaster::dispatchPendingMessages()
  92 {
  93     callback.handleUpdateNowIfNeeded();
  94 }
  95
  96 void ChangeBroadcaster::callListeners()
  97 {
  98     changeListeners.call (&ChangeListener::changeListenerCallback, this);
  99 }
 100
 101 //==============================================================================
 102 ChangeBroadcaster::ChangeBroadcasterCallback::ChangeBroadcasterCallback()
 103     : owner (nullptr)
 104 {
 105 }
 106
 107 void ChangeBroadcaster::ChangeBroadcasterCallback::handleAsyncUpdate()
 108 {
 109     jassert (owner != nullptr);
 110     owner->callListeners();
 111 }
 112
 113
 114 END_JUCE_NAMESPACE