blob: d4e7f35885235a003eaeb6f148b264c667405eda (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
#pragma once
#include <osl/mutex.hxx>
#include <osl/conditn.hxx>
namespace framework{
/*-************************************************************************************************************
@short implement a gate to block multiple threads at the same time or unblock all
@descr A gate can be used as a negative-condition! You can open a "door" - wait() will not block ...
or you can close it - wait() blocks till open() is called again.
Then all currently waiting threads are running immediately - but new ones are blocked!
@attention To prevent us against wrong using, the default ctor, copy ctor and the =operator are marked private!
@devstatus ready to use
*//*-*************************************************************************************************************/
class Gate
{
// public methods
public:
/*-****************************************************************************************************
@short ctor
@descr These initialize the object right as an open gate.
*//*-*****************************************************************************************************/
Gate()
: m_bClosed ( false )
{
open();
}
/*-****************************************************************************************************
@short dtor
@descr Is user forget it - we open the gate ...
blocked threads can running ... but I don't know
if it's right - we are destroyed yet!?
*//*-*****************************************************************************************************/
~Gate()
{
open();
}
/*-****************************************************************************************************
@short copy-ctor
@descr Forbid copy construction
*//*-*****************************************************************************************************/
Gate(const Gate&) = delete;
/*-****************************************************************************************************
@short copy-assignment
@descr Forbid copy assigning
*//*-*****************************************************************************************************/
Gate& operator=(const Gate&) = delete;
/*-****************************************************************************************************
@short open the gate
@descr A wait() call will not block then.
@seealso method close()
*//*-*****************************************************************************************************/
void open()
{
// We must safe access to our internal member!
::osl::MutexGuard aLock( m_aAccessLock );
// Set condition -> wait don't block any longer -> gate is open
m_aPassage.set();
// Check if operation was successful!
// Check returns false if condition isn't set => m_bClosed will be true then => we must return false; opening failed
m_bClosed = !m_aPassage.check();
}
/*-****************************************************************************************************
@short close the gate
@descr A wait() call will block then.
@seealso method open()
*//*-*****************************************************************************************************/
void close()
{
// We must safe access to our internal member!
::osl::MutexGuard aLock( m_aAccessLock );
// Reset condition -> wait blocks now -> gate is closed
m_aPassage.reset();
// Check if operation was successful!
// Check returns false if condition was reset => m_bClosed will be true then => we can return true; closing ok
m_bClosed = !m_aPassage.check();
}
/*-****************************************************************************************************
@short must be called to pass the gate
@descr If gate "open" => wait() will not block.
If gate "closed" => wait() will block till somewhere open it again.
@seealso method wait()
@seealso method open()
*//*-*****************************************************************************************************/
void wait()
{
// We must safe access to our internal member!
::osl::ClearableMutexGuard aLock( m_aAccessLock );
// If gate not closed - caller can pass it.
if( m_bClosed )
{
// Then we must release used access lock -
// because next call will block...
// and if we hold the access lock nobody else can use this object without a deadlock!
aLock.clear();
// Wait for opening gate...
m_aPassage.wait();
}
}
// private member
private:
::osl::Mutex m_aAccessLock;
::osl::Condition m_aPassage;
bool m_bClosed;
}; // class Gate
} // namespace framework
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|
