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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /*
3 : * This file is part of the LibreOffice project.
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5 : * This Source Code Form is subject to the terms of the Mozilla Public
6 : * License, v. 2.0. If a copy of the MPL was not distributed with this
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8 : *
9 : * This file incorporates work covered by the following license notice:
10 : *
11 : * Licensed to the Apache Software Foundation (ASF) under one or more
12 : * contributor license agreements. See the NOTICE file distributed
13 : * with this work for additional information regarding copyright
14 : * ownership. The ASF licenses this file to you under the Apache
15 : * License, Version 2.0 (the "License"); you may not use this file
16 : * except in compliance with the License. You may obtain a copy of
17 : * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18 : */
19 :
20 : #ifndef INCLUDED_FRAMEWORK_INC_THREADHELP_GATE_HXX
21 : #define INCLUDED_FRAMEWORK_INC_THREADHELP_GATE_HXX
22 :
23 : #include <boost/noncopyable.hpp>
24 : #include <osl/time.h>
25 : #include <osl/mutex.hxx>
26 : #include <osl/conditn.hxx>
27 :
28 : namespace framework{
29 :
30 : /*-************************************************************************************************************
31 : @short implement a gate to block multiple threads at same time or unblock all
32 : @descr A gate can be used as a negative-condition! You can open a "door" - wait() will not block ...
33 : or you can close it - wait() blocks till open() is called again.
34 : Then all currently waiting threads are running immediately - but new ones are blocked!
35 :
36 : @attention To prevent us against wrong using, the default ctor, copy ctor and the =operator are marked private!
37 :
38 : @devstatus ready to use
39 : *//*-*************************************************************************************************************/
40 : class Gate : private boost::noncopyable
41 : {
42 :
43 : // public methods
44 :
45 : public:
46 :
47 : /*-****************************************************************************************************
48 : @short ctor
49 : @descr These initialize the object right as an open gate.
50 : *//*-*****************************************************************************************************/
51 6988 : inline Gate()
52 6988 : : m_bClosed ( false )
53 : {
54 6988 : open();
55 6988 : }
56 :
57 : /*-****************************************************************************************************
58 : @short dtor
59 : @descr Is user forget it - we open the gate ...
60 : blocked threads can running ... but I don't know
61 : if it's right - we are destroyed yet!?
62 : *//*-*****************************************************************************************************/
63 6382 : inline ~Gate()
64 6382 : {
65 6382 : open();
66 6382 : }
67 :
68 : /*-****************************************************************************************************
69 : @short open the gate
70 : @descr A wait() call will not block then.
71 :
72 : @seealso method close()
73 : *//*-*****************************************************************************************************/
74 742637 : void open()
75 : {
76 : // We must safe access to our internal member!
77 742637 : ::osl::MutexGuard aLock( m_aAccessLock );
78 : // Set condition -> wait don't block any longer -> gate is open
79 742637 : m_aPassage.set();
80 : // Check if operation was successful!
81 : // Check returns false if condition isn't set => m_bClosed will be true then => we must return false; opening failed
82 742637 : m_bClosed = !m_aPassage.check();
83 742637 : }
84 :
85 : /*-****************************************************************************************************
86 : @short close the gate
87 : @descr A wait() call will block then.
88 :
89 : @seealso method open()
90 : *//*-*****************************************************************************************************/
91 722279 : void close()
92 : {
93 : // We must safe access to our internal member!
94 722279 : ::osl::MutexGuard aLock( m_aAccessLock );
95 : // Reset condition -> wait blocks now -> gate is closed
96 722279 : m_aPassage.reset();
97 : // Check if operation was successful!
98 : // Check returns false if condition was reseted => m_bClosed will be true then => we can return true; closing ok
99 722279 : m_bClosed = !m_aPassage.check();
100 722279 : }
101 :
102 : /*-****************************************************************************************************
103 : @short must be called to pass the gate
104 : @descr If gate "open" => wait() will not block.
105 : If gate "closed" => wait() will block till somewhere open it again.
106 :
107 : @seealso method wait()
108 : @seealso method open()
109 :
110 : @param "pTimeOut", optional parameter to wait a certain time
111 : @return true, if wait was successful (gate was opened)
112 : false, if condition has an error or timeout was reached!
113 :
114 : @onerror We return false.
115 : *//*-*****************************************************************************************************/
116 6966 : bool wait(const TimeValue* pTimeOut = nullptr)
117 : {
118 : // We must safe access to our internal member!
119 6966 : ::osl::ClearableMutexGuard aLock( m_aAccessLock );
120 : // If gate not closed - caller can pass it.
121 6966 : bool bSuccessful = true;
122 6966 : if( m_bClosed )
123 : {
124 : // Then we must release used access lock -
125 : // because next call will block ...
126 : // and if we hold the access lock nobody else can use this object without a dadlock!
127 0 : aLock.clear();
128 : // Wait for opening gate ...
129 0 : bSuccessful = ( m_aPassage.wait( pTimeOut ) == ::osl::Condition::result_ok );
130 : }
131 :
132 6966 : return bSuccessful;
133 : }
134 :
135 : // private member
136 :
137 : private:
138 :
139 : ::osl::Mutex m_aAccessLock;
140 : ::osl::Condition m_aPassage;
141 : bool m_bClosed;
142 :
143 : }; // class Gate
144 :
145 : } // namespace framework
146 :
147 : #endif // INCLUDED_FRAMEWORK_INC_THREADHELP_GATE_HXX
148 :
149 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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