1 martin 1.14 //%LICENSE////////////////////////////////////////////////////////////////

  2 martin 1.15 //

  3 martin 1.14 // 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.

  9 martin 1.15 //

 10 martin 1.14 // 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:

 16 martin 1.15 //

 17 martin 1.14 // The above copyright notice and this permission notice shall be included
 18             // in all copies or substantial portions of the Software.

 19 martin 1.15 //

 20 martin 1.14 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 21 martin 1.15 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 22 martin 1.14 // 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.

 27 martin 1.15 //

 28 martin 1.14 //////////////////////////////////////////////////////////////////////////

 29 mike   1.2  //
 30             //%/////////////////////////////////////////////////////////////////////////////
 31             
 32             #include "ReadWriteSem.h"
 33             #include "Time.h"
 34             #include "PegasusAssert.h"
 35             #include "Threads.h"

 36 kumpf  1.13 #include "Exception.h"
 37             #include "System.h"

 38 mike   1.2  
 39             PEGASUS_NAMESPACE_BEGIN
 40             
 41             //==============================================================================
 42             //
 43             // PEGASUS_USE_POSIX_RWLOCK
 44             //
 45             //==============================================================================
 46             
 47             #ifdef PEGASUS_USE_POSIX_RWLOCK
 48             

 49 kumpf  1.12 ReadWriteSem::ReadWriteSem()

 50 mike   1.2  {
 51                 pthread_rwlock_init(&_rwlock.rwlock, NULL);
 52             }
 53             
 54             ReadWriteSem::~ReadWriteSem()
 55             {

 56 kumpf  1.5      int r = 0;

 57 mike   1.6      while ((r = pthread_rwlock_destroy(&_rwlock.rwlock)) == EBUSY ||

 58 kumpf  1.5             (r == -1 && errno == EBUSY))

 59 mike   1.2      {
 60                     Threads::yield();
 61                 }
 62             }
 63             

 64 kumpf  1.12 void ReadWriteSem::waitRead()

 65 mike   1.2  {

 66 kumpf  1.13     int r = pthread_rwlock_rdlock(&_rwlock.rwlock);
 67             
 68                 if (r != 0)

 69 mike   1.2      {

 70 kumpf  1.13         if (r != -1)
 71                     {
 72                         // Special behavior for Single UNIX Specification, Version 3
 73                         errno = r;
 74                     }
 75             
 76                     throw Exception(MessageLoaderParms(
 77                         "Common.InternalException.READ_LOCK_FAILED",
 78                         "Failed to acquire read lock: $0",
 79                         PEGASUS_SYSTEM_ERRORMSG_NLS));

 80 mike   1.2      }
 81             }
 82             

 83 kumpf  1.12 void ReadWriteSem::waitWrite()

 84 mike   1.2  {

 85 kumpf  1.13     int r = pthread_rwlock_wrlock(&_rwlock.rwlock);
 86             
 87                 if (r != 0)

 88 mike   1.2      {

 89 kumpf  1.13         if (r != -1)
 90                     {
 91                         // Special behavior for Single UNIX Specification, Version 3
 92                         errno = r;
 93                     }
 94             
 95                     throw Exception(MessageLoaderParms(
 96                         "Common.InternalException.WRITE_LOCK_FAILED",
 97                         "Failed to acquire write lock: $0",
 98                         PEGASUS_SYSTEM_ERRORMSG_NLS));

 99 mike   1.2      }

100 kumpf  1.12 }

101 kumpf  1.10 

102 kumpf  1.12 void ReadWriteSem::unlockRead()
103             {

104 kumpf  1.10     int rc = pthread_rwlock_unlock(&_rwlock.rwlock);
105                 // All documented error codes represent coding errors.
106                 PEGASUS_ASSERT(rc == 0);

107 mike   1.2  }
108             

109 kumpf  1.12 void ReadWriteSem::unlockWrite()

110 mike   1.2  {

111 kumpf  1.12     int rc = pthread_rwlock_unlock(&_rwlock.rwlock);
112                 // All documented error codes represent coding errors.
113                 PEGASUS_ASSERT(rc == 0);

114 mike   1.2  }
115             
116             #endif /* PEGASUS_USE_POSIX_RWLOCK */
117             
118             //==============================================================================
119             //
120             // PEGASUS_USE_SEMAPHORE_RWLOCK
121             //
122             //==============================================================================
123             
124             #if defined(PEGASUS_USE_SEMAPHORE_RWLOCK)
125             
126             // // If i get cancelled, I MUST ensure:
127             // 1) I do not hold the internal mutex
128             // 2) I do not hold the write lock
129             // 3) I am not using a reader slot
130             

131 kumpf  1.12 ReadWriteSem::ReadWriteSem() : _rwlock()

132 mike   1.2  {
133             }
134             
135             ReadWriteSem::~ReadWriteSem()
136             {
137                 // lock everyone out of this object
138                 try
139                 {
140                     _rwlock._internal_lock.lock();
141                 }

142 kumpf  1.13     catch (...)

143 mike   1.2      {
144                     PEGASUS_ASSERT(0);
145                 }

146 kumpf  1.12     while (_rwlock._readers.get() > 0 || _rwlock._writers.get() > 0)

147 mike   1.2      {
148                     Threads::yield();
149                 }
150                 _rwlock._internal_lock.unlock();
151             }
152             

153 kumpf  1.12 void ReadWriteSem::waitRead()

154 mike   1.2  {

155 kumpf  1.12     // Lock the internal mutex to ensure only one waiter is processed at a time.
156                 AutoMutex lock(_rwlock._internal_lock);
157             
158                 // Wait for the existing writer (if any) to clear.
159                 while (_rwlock._writers.get() > 0)
160                 {
161                     Threads::yield();

162 mike   1.2      }

163 kumpf  1.12 
164                 // Wait for a reader slot to open up.
165                 _rwlock._rlock.wait();
166             
167                 // Increment the number of readers.
168                 _rwlock._readers++;
169             }
170             
171             void ReadWriteSem::waitWrite()
172             {
173                 // Lock the internal mutex to ensure only one waiter is processed at a time.
174                 AutoMutex lock(_rwlock._internal_lock);
175             
176                 // Allow all the readers to exit.
177                 while (_rwlock._readers.get() > 0)
178                 {
179                     Threads::yield();
180                 }
181             
182                 // Obtain the write mutex.
183                 _rwlock._wlock.lock();
184 kumpf  1.12 
185                 // Set the writer count to one.
186                 _rwlock._writers = 1;

187 mike   1.2  }
188             

189 kumpf  1.12 void ReadWriteSem::unlockRead()

190 mike   1.2  {

191 kumpf  1.12     PEGASUS_ASSERT(_rwlock._readers.get() > 0);
192                 _rwlock._readers--;
193                 _rwlock._rlock.signal();

194 mike   1.2  }
195             

196 kumpf  1.12 void ReadWriteSem::unlockWrite()

197 mike   1.2  {

198 kumpf  1.12     PEGASUS_ASSERT(_rwlock._writers.get() == 1);
199                 _rwlock._writers = 0;
200                 _rwlock._wlock.unlock();

201 mike   1.2  }
202             
203             #endif /* !PEGASUS_USE_SEMAPHORE_RWLOCK */
204             
205             PEGASUS_NAMESPACE_END