1 martin 1.5 //%LICENSE////////////////////////////////////////////////////////////////
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2 martin 1.6 //
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3 martin 1.5 // Licensed to The Open Group (TOG) under one or more contributor license
4 // agreements. Refer to the OpenPegasusNOTICE.txt file distributed with
5 // this work for additional information regarding copyright ownership.
6 // Each contributor licenses this file to you under the OpenPegasus Open
7 // Source License; you may not use this file except in compliance with the
8 // License.
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9 martin 1.6 //
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10 martin 1.5 // Permission is hereby granted, free of charge, to any person obtaining a
11 // copy of this software and associated documentation files (the "Software"),
12 // to deal in the Software without restriction, including without limitation
13 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
14 // and/or sell copies of the Software, and to permit persons to whom the
15 // Software is furnished to do so, subject to the following conditions:
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16 martin 1.6 //
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17 martin 1.5 // The above copyright notice and this permission notice shall be included
18 // in all copies or substantial portions of the Software.
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19 martin 1.6 //
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20 martin 1.5 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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21 martin 1.6 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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22 martin 1.5 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
23 // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
24 // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
25 // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
26 // SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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27 martin 1.6 //
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28 martin 1.5 //////////////////////////////////////////////////////////////////////////
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29 mike 1.2 //
30 //%/////////////////////////////////////////////////////////////////////////////
31
32 #ifndef Pegasus_Condition_h
33 #define Pegasus_Condition_h
34
35 #include <Pegasus/Common/Config.h>
36 #include <Pegasus/Common/Linkage.h>
37 #include <Pegasus/Common/Mutex.h>
38 #include <Pegasus/Common/AtomicInt.h>
39
40 #if defined(PEGASUS_HAVE_PTHREADS)
41 # include <pthread.h>
42 #elif defined(PEGASUS_HAVE_WINDOWS_THREADS)
43 # include <windows.h>
44 # include "List.h"
45 #else
46 # error "<Pegasus/Common/Condition.h>: not implemented"
47 #endif
48
49 PEGASUS_NAMESPACE_BEGIN
50 mike 1.2
51 //==============================================================================
52 //
53 // ConditionRep
54 //
55 //==============================================================================
56
57 #if defined(PEGASUS_HAVE_PTHREADS)
58
59 struct ConditionRep
60 {
61 pthread_cond_t cond;
62 };
63
64 #endif /* PEGASUS_HAVE_PTHREADS */
65
66 #if defined(PEGASUS_HAVE_WINDOWS_THREADS)
67
68 struct ConditionWaiter : public Linkable
69 {
70 HANDLE event;
71 mike 1.2 };
72
73 struct ConditionRep
74 {
75 List<ConditionWaiter,Mutex> waiters;
76 };
77
78 #endif /* PEGASUS_HAVE_WINDOWS_THREADS */
79
80 //==============================================================================
81 //
82 // Condition
83 //
84 //==============================================================================
85
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86 karl 1.6.8.1 /**
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87 karl 1.6.8.2 * This class defines a condition variable based on the
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88 karl 1.6.8.1 * Pthreads model that allows signaling between threads for more complex
89 * conditions than semaphores.
90 * The general pattern for a condition variable is:
91 * 1. Define the condition variable and corresponding Mutex
92 * Condition testCondition;
93 * Mutex testCondtionMutex;
94 *
95 * 2. Define the condition wait logic as a while loop and protect it with
96 * the mutex.
97 *
98 * testConditionMutex.lock();
99 * while (testdata < 3 && !endOfTransaction)
100 * {
101 * testCondition.wait(testConditionMutex)
102 * }
103 * testConditionMutex.unlock();
104 *
105 * If the condition is true, execution continues. If not, the wait is
106 * executed which unlocks the mutex and goes to sleep to wait for a signal
107 * on the definedcondition variable from another thread. Pthreads
108 * DOES not guarantee that there will not be spurious signals so the
109 karl 1.6.8.1 * condition wait loop MUST test for the condition.
110 * . . .
111 * 3. As part of some thread, define the signal function as follows.
112 * When the following signal code is executed, the condition variable in
113 * one thread in the wait condition will be awakened.
114 *
115 * testConditionMutex.lock();
116 * testCondition.signal();
117 * testCondition.unlock();
118 *
119 * The user should be careful that the conditions are only modified under
120 * control of the mutex associated with the condition variable.
121 */
122
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123 mike 1.2 class PEGASUS_COMMON_LINKAGE Condition
124 {
125 public:
126
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127 karl 1.6.8.1 /**
128 * Define a condition variable.
129 *
130 */
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131 mike 1.2 Condition();
132
133 ~Condition();
134
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135 karl 1.6.8.1 /**
136 * Signal the condition variable that the condition might be
137 * satisfied. The signal should always be protected by the
138 * condition mutex and need not fully test the condition when
139 * executed.
140 */
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141 mike 1.2 void signal();
142
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143 karl 1.6.8.1 /**
144 * Wait on the signal from another thread for the defined
145 * condition variable. The wait will return when a signal is
146 * received. The wait function should always be protected by
147 * the condition mutex. Each time the wait is executed it
148 * unlocks the mutex, sleeps awating a signal. When a signal is
149 * received, the mutex is locked.
150 *
151 * @param mutex - Condition variable mutex that should protect
152 * both the wait and signal execution.
153 */
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154 mike 1.2 void wait(Mutex& mutex);
155
156 private:
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157 mike 1.3 Condition(const Condition&);
158 Condition& operator=(const Condition&);
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159 mike 1.2 ConditionRep _rep;
160 };
161
162 PEGASUS_NAMESPACE_END
163
164 #endif /* Pegasus_Condition_h */
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Condition.h
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