1/*
2 * Copyright (c) 1999-2000, Eric Moon.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions, and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions, and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * 3. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
23 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
27 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31
32// ObservableLooper.h
33// * PURPOSE
34//   Implementation of an observable (target) derived
35//   from BLooper.
36//
37// * HISTORY
38//   e.moon		18aug99		Begun
39
40#ifndef __ObservableLooper_H__
41#define __ObservableLooper_H__
42
43#include <Looper.h>
44class BMessageRunner;
45
46#include "observe.h"
47#include "IObservable.h"
48#include "MultiInvoker.h"
49
50#include "cortex_defs.h"
51__BEGIN_CORTEX_NAMESPACE
52
53class ObservableLooper :
54	public	BLooper,
55	public	IObservable,
56	private	MultiInvoker {
57
58	typedef BLooper _inherited;
59
60public:											// *** deletion
61	// clients must call release() rather than deleting,
62	// to ensure that all observers are notified of the
63	// object's demise.  if the object has already been
64	// released, return an error.
65
66	virtual status_t release();
67
68public:											// *** ctor/dtor
69	virtual ~ObservableLooper();
70	ObservableLooper(
71		const char*							name=0,
72		int32										priority=B_NORMAL_PRIORITY,
73		int32										portCapacity=B_LOOPER_PORT_DEFAULT_CAPACITY,
74		bigtime_t								quitTimeout=B_INFINITE_TIMEOUT);
75	ObservableLooper(
76		BMessage*								archive);
77
78public:											// *** accessors
79	// return true if release() has been called, false otherwise.
80	bool isReleased() const;
81
82protected:									// *** hooks
83	// sends M_OBSERVER_ADDED to the newly-added observer
84	virtual void observerAdded(
85		const BMessenger&				observer);
86
87	// sends M_OBSERVER_REMOVED to the newly-removed observer
88	virtual void observerRemoved(
89		const BMessenger&				observer);
90
91protected:									// *** internal operations
92	// call to send the given message to all observers.
93	// Responsibility for deletion of the message remains with
94	// the caller.
95	// * LOCKING: the BLooper must be locked.
96	virtual status_t notify(
97		BMessage*								message);
98
99	// sends M_RELEASE_OBSERVABLE
100	virtual void notifyRelease();
101
102public:											// *** BLooper
103	virtual void Quit();
104	virtual bool QuitRequested();
105
106public:											// *** BHandler
107	virtual void MessageReceived(
108		BMessage*								message);
109
110public:											// *** BArchivable
111	// * LOCKING: the BLooper must be locked.
112	virtual status_t Archive(
113		BMessage*								archive,
114		bool										deep=true) const;
115
116private:										// implementation
117	void _handleAddObserver(
118		BMessage*								message);
119
120	void _handleRemoveObserver(
121		BMessage*								message);
122
123private:										// members
124	// how long to wait after being requested to shut down
125	// before giving up on stuck observers
126	bigtime_t									m_quitTimeout;
127	BMessageRunner*						m_executioner;
128
129	// true if a quit has been requested
130	bool											m_quitting;
131};
132
133__END_CORTEX_NAMESPACE
134#endif /*__ObservableLooper_H__*/
135
136