xref: /haiku/src/servers/app/MessageLooper.cpp (revision 37d96a4c637d81f25dec869941892f8f8c5e4d42)
1 /*
2  * Copyright 2005, Haiku.
3  * Distributed under the terms of the MIT License.
4  *
5  * Authors:
6  *		Axel Dörfler, axeld@pinc-software.de
7  */
8 
9 
10 #include "MessageLooper.h"
11 
12 #include <Autolock.h>
13 #include <stdio.h>
14 #include <string.h>
15 
16 
17 MessageLooper::MessageLooper(const char* name)
18 	: BLocker(name),
19 	fQuitting(false)
20 {
21 }
22 
23 
24 MessageLooper::~MessageLooper()
25 {
26 }
27 
28 
29 bool
30 MessageLooper::Run()
31 {
32 	BAutolock locker(this);
33 
34 	fQuitting = false;
35 
36 	char name[B_OS_NAME_LENGTH];
37 	_GetLooperName(name, sizeof(name));
38 
39 	// Spawn our message-monitoring thread
40 	fThread = spawn_thread(_message_thread, name, B_NORMAL_PRIORITY, this);
41 	if (fThread < B_OK) {
42 		fQuitting = true;
43 		return false;
44 	}
45 
46 	if (resume_thread(fThread) != B_OK) {
47 		fQuitting = true;
48 		kill_thread(fThread);
49 		fThread = -1;
50 		return false;
51 	}
52 
53 	return true;
54 }
55 
56 
57 void
58 MessageLooper::Quit()
59 {
60 	fQuitting = true;
61 	_PrepareQuit();
62 
63 	if (fThread < B_OK) {
64 		// thread has not been started yet
65 		delete this;
66 		return;
67 	}
68 
69 	if (fThread == find_thread(NULL)) {
70 		// called from our message looper
71 		delete this;
72 		exit_thread(0);
73 	} else {
74 		// called from a different thread
75 		PostMessage(kMsgQuitLooper);
76 	}
77 }
78 
79 
80 /*!
81 	\brief Send a message to the looper without any attachments
82 	\param code ID code of the message to post
83 */
84 void
85 MessageLooper::PostMessage(int32 code)
86 {
87 	BPrivate::LinkSender link(MessagePort());
88 	link.StartMessage(code);
89 	link.Flush();
90 }
91 
92 
93 void
94 MessageLooper::_PrepareQuit()
95 {
96 	// to be implemented by subclasses
97 }
98 
99 
100 void
101 MessageLooper::_GetLooperName(char* name, size_t length)
102 {
103 	strcpy(name, "unnamed looper");
104 }
105 
106 
107 void
108 MessageLooper::_DispatchMessage(int32 code, BPrivate::LinkReceiver &link)
109 {
110 }
111 
112 
113 void
114 MessageLooper::_MessageLooper()
115 {
116 	BPrivate::LinkReceiver& receiver = fLink.Receiver();
117 
118 	while (true) {
119 		int32 code;
120 		status_t status = receiver.GetNextMessage(code);
121 		if (status < B_OK) {
122 			// that shouldn't happen, it's our port
123 			printf("Someone deleted our message port!\n");
124 			break;
125 		}
126 
127 		Lock();
128 
129 		if (code == kMsgQuitLooper) {
130 			Quit();
131 		} else
132 			_DispatchMessage(code, receiver);
133 
134 		Unlock();
135 	}
136 }
137 
138 
139 /*!
140 	\brief Message-dispatching loop starter
141 */
142 /*static*/
143 int32
144 MessageLooper::_message_thread(void* _looper)
145 {
146 	MessageLooper* looper = (MessageLooper*)_looper;
147 
148 	looper->_MessageLooper();
149 	return 0;
150 }
151 
152