source/modules/juce_events/native/juce_osx_MessageQueue.h

   1 /*
   2   ==============================================================================
   3
   4    This file is part of the JUCE library.
   5    Copyright (c) 2022 - Raw Material Software Limited
   6
   7    JUCE is an open source library subject to commercial or open-source
   8    licensing.
   9
  10    The code included in this file is provided under the terms of the ISC license
  11    http://www.isc.org/downloads/software-support-policy/isc-license. Permission
  12    To use, copy, modify, and/or distribute this software for any purpose with or
  13    without fee is hereby granted provided that the above copyright notice and
  14    this permission notice appear in all copies.
  15
  16    JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
  17    EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
  18    DISCLAIMED.
  19
  20   ==============================================================================
  21 */
  22
  23 namespace juce
  24 {
  25
  26 //==============================================================================
  27 /* An internal message pump class used in OSX and iOS. */
  28 class MessageQueue
  29 {
  30 public:
  31     MessageQueue()
  32     {
  33        #if JUCE_IOS
  34         runLoop = CFRunLoopGetCurrent();
  35        #else
  36         runLoop = CFRunLoopGetMain();
  37        #endif
  38
  39         CFRunLoopSourceContext sourceContext;
  40         zerostruct (sourceContext); // (can't use "= { 0 }" on this object because it's typedef'ed as a C struct)
  41         sourceContext.info = this;
  42         sourceContext.perform = runLoopSourceCallback;
  43         runLoopSource.reset (CFRunLoopSourceCreate (kCFAllocatorDefault, 1, &sourceContext));
  44         CFRunLoopAddSource (runLoop, runLoopSource.get(), kCFRunLoopCommonModes);
  45     }
  46
  47     ~MessageQueue() noexcept
  48     {
  49         CFRunLoopRemoveSource (runLoop, runLoopSource.get(), kCFRunLoopCommonModes);
  50         CFRunLoopSourceInvalidate (runLoopSource.get());
  51     }
  52
  53     void post (MessageManager::MessageBase* const message)
  54     {
  55         messages.add (message);
  56         wakeUp();
  57     }
  58
  59 private:
  60     ReferenceCountedArray<MessageManager::MessageBase, CriticalSection> messages;
  61     CFRunLoopRef runLoop;
  62     CFUniquePtr<CFRunLoopSourceRef> runLoopSource;
  63
  64     void wakeUp() noexcept
  65     {
  66         CFRunLoopSourceSignal (runLoopSource.get());
  67         CFRunLoopWakeUp (runLoop);
  68     }
  69
  70     bool deliverNextMessage()
  71     {
  72         const MessageManager::MessageBase::Ptr nextMessage (messages.removeAndReturn (0));
  73
  74         if (nextMessage == nullptr)
  75             return false;
  76
  77         JUCE_AUTORELEASEPOOL
  78         {
  79             JUCE_TRY
  80             {
  81                 nextMessage->messageCallback();
  82             }
  83             JUCE_CATCH_EXCEPTION
  84         }
  85
  86         return true;
  87     }
  88
  89     void runLoopCallback() noexcept
  90     {
  91         for (int i = 4; --i >= 0;)
  92             if (! deliverNextMessage())
  93                 return;
  94
  95         wakeUp();
  96     }
  97
  98     static void runLoopSourceCallback (void* info) noexcept
  99     {
 100         static_cast<MessageQueue*> (info)->runLoopCallback();
 101     }
 102 };
 103
 104 } // namespace juce