1 /*
2   ==============================================================================
3 
4    This file is part of the JUCE library.
5    Copyright (c) 2020 - 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:
MessageQueue()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 = CFRunLoopSourceCreate (kCFAllocatorDefault, 1, &sourceContext);
44         CFRunLoopAddSource (runLoop, runLoopSource, kCFRunLoopCommonModes);
45     }
46 
~MessageQueue()47     ~MessageQueue() noexcept
48     {
49         CFRunLoopRemoveSource (runLoop, runLoopSource, kCFRunLoopCommonModes);
50         CFRunLoopSourceInvalidate (runLoopSource);
51         CFRelease (runLoopSource);
52     }
53 
post(MessageManager::MessageBase * const message)54     void post (MessageManager::MessageBase* const message)
55     {
56         messages.add (message);
57         wakeUp();
58     }
59 
60 private:
61     ReferenceCountedArray<MessageManager::MessageBase, CriticalSection> messages;
62     CFRunLoopRef runLoop;
63     CFRunLoopSourceRef runLoopSource;
64 
wakeUp()65     void wakeUp() noexcept
66     {
67         CFRunLoopSourceSignal (runLoopSource);
68         CFRunLoopWakeUp (runLoop);
69     }
70 
deliverNextMessage()71     bool deliverNextMessage()
72     {
73         const MessageManager::MessageBase::Ptr nextMessage (messages.removeAndReturn (0));
74 
75         if (nextMessage == nullptr)
76             return false;
77 
78         JUCE_AUTORELEASEPOOL
79         {
80             JUCE_TRY
81             {
82                 nextMessage->messageCallback();
83             }
84             JUCE_CATCH_EXCEPTION
85         }
86 
87         return true;
88     }
89 
runLoopCallback()90     void runLoopCallback() noexcept
91     {
92         for (int i = 4; --i >= 0;)
93             if (! deliverNextMessage())
94                 return;
95 
96         wakeUp();
97     }
98 
runLoopSourceCallback(void * info)99     static void runLoopSourceCallback (void* info) noexcept
100     {
101         static_cast<MessageQueue*> (info)->runLoopCallback();
102     }
103 };
104 
105 } // namespace juce
106