version 1.9, 2008/08/15 23:14:01
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version 1.15.8.1, 2013/06/03 22:35:13
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//%2006//////////////////////////////////////////////////////////////////////// |
//%LICENSE//////////////////////////////////////////////////////////////// |
// | // |
// Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development |
// Licensed to The Open Group (TOG) under one or more contributor license |
// Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems. |
// agreements. Refer to the OpenPegasusNOTICE.txt file distributed with |
// Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.; |
// this work for additional information regarding copyright ownership. |
// IBM Corp.; EMC Corporation, The Open Group. |
// Each contributor licenses this file to you under the OpenPegasus Open |
// Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.; |
// Source License; you may not use this file except in compliance with the |
// IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group. |
// License. |
// Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.; |
// |
// EMC Corporation; VERITAS Software Corporation; The Open Group. |
// Permission is hereby granted, free of charge, to any person obtaining a |
// Copyright (c) 2006 Hewlett-Packard Development Company, L.P.; IBM Corp.; |
// copy of this software and associated documentation files (the "Software"), |
// EMC Corporation; Symantec Corporation; The Open Group. |
// to deal in the Software without restriction, including without limitation |
// |
// the rights to use, copy, modify, merge, publish, distribute, sublicense, |
// Permission is hereby granted, free of charge, to any person obtaining a copy |
// and/or sell copies of the Software, and to permit persons to whom the |
// of this software and associated documentation files (the "Software"), to |
// Software is furnished to do so, subject to the following conditions: |
// deal in the Software without restriction, including without limitation the |
// |
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
// The above copyright notice and this permission notice shall be included |
// sell copies of the Software, and to permit persons to whom the Software is |
// in all copies or substantial portions of the Software. |
// furnished to do so, subject to the following conditions: |
// |
// |
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN |
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED |
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT |
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR |
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT |
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
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// | // |
//============================================================================== |
////////////////////////////////////////////////////////////////////////// |
// | // |
//%///////////////////////////////////////////////////////////////////////////// | //%///////////////////////////////////////////////////////////////////////////// |
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#include "Time.h" | #include "Time.h" |
#include "PegasusAssert.h" | #include "PegasusAssert.h" |
#include "Threads.h" | #include "Threads.h" |
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#include "Exception.h" |
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#include "System.h" |
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PEGASUS_NAMESPACE_BEGIN | PEGASUS_NAMESPACE_BEGIN |
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#ifdef PEGASUS_USE_POSIX_RWLOCK | #ifdef PEGASUS_USE_POSIX_RWLOCK |
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ReadWriteSem::ReadWriteSem():_readers(0), _writers(0) |
ReadWriteSem::ReadWriteSem() |
{ | { |
pthread_rwlock_init(&_rwlock.rwlock, NULL); | pthread_rwlock_init(&_rwlock.rwlock, NULL); |
Threads::clear(_rwlock.owner); |
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} | } |
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ReadWriteSem::~ReadWriteSem() | ReadWriteSem::~ReadWriteSem() |
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} | } |
} | } |
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void ReadWriteSem::_wait(Boolean writeLock, ThreadType caller) |
void ReadWriteSem::waitRead() |
{ |
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if (writeLock) |
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{ |
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if (0 == pthread_rwlock_wrlock(&_rwlock.rwlock)) |
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{ | { |
_rwlock.owner = caller; |
int r = pthread_rwlock_rdlock(&_rwlock.rwlock); |
_writers++; |
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return; |
if (r != 0) |
} |
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} |
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else |
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{ | { |
if (0 == pthread_rwlock_rdlock(&_rwlock.rwlock)) |
if (r != -1) |
{ | { |
_readers++; |
// Special behavior for Single UNIX Specification, Version 3 |
return; |
errno = r; |
} |
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} | } |
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throw WaitFailed(Threads::self()); |
throw Exception(MessageLoaderParms( |
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"Common.InternalException.READ_LOCK_FAILED", |
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"Failed to acquire read lock: $0", |
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PEGASUS_SYSTEM_ERRORMSG_NLS)); |
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} |
} | } |
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void ReadWriteSem::_unlock(Boolean writeLock, ThreadType caller) |
void ReadWriteSem::waitWrite() |
{ | { |
ThreadType owner; |
int r = pthread_rwlock_wrlock(&_rwlock.rwlock); |
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if (writeLock) |
if (r != 0) |
{ | { |
owner = _rwlock.owner; |
if (r != -1) |
Threads::clear(_rwlock.owner); |
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} |
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if (0 != pthread_rwlock_unlock(&_rwlock.rwlock)) |
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{ | { |
_rwlock.owner = owner; |
// Special behavior for Single UNIX Specification, Version 3 |
throw(Permission(Threads::self())); |
errno = r; |
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} |
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throw Exception(MessageLoaderParms( |
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"Common.InternalException.WRITE_LOCK_FAILED", |
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"Failed to acquire write lock: $0", |
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PEGASUS_SYSTEM_ERRORMSG_NLS)); |
} | } |
if (!writeLock && _readers.get() != 0) |
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_readers--; |
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else if (_writers.get() != 0) |
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_writers--; |
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} | } |
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int ReadWriteSem::read_count() const |
void ReadWriteSem::unlockRead() |
{ | { |
return _readers.get(); |
// All documented error codes represent coding errors. |
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PEGASUS_FCT_EXECUTE_AND_ASSERT(0, pthread_rwlock_unlock(&_rwlock.rwlock)); |
} | } |
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int ReadWriteSem::write_count() const |
void ReadWriteSem::unlockWrite() |
{ | { |
return _writers.get(); |
// All documented error codes represent coding errors. |
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PEGASUS_FCT_EXECUTE_AND_ASSERT(0, pthread_rwlock_unlock(&_rwlock.rwlock)); |
} | } |
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#endif /* PEGASUS_USE_POSIX_RWLOCK */ | #endif /* PEGASUS_USE_POSIX_RWLOCK */ |
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// 2) I do not hold the write lock | // 2) I do not hold the write lock |
// 3) I am not using a reader slot | // 3) I am not using a reader slot |
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ReadWriteSem::ReadWriteSem():_readers(0), _writers(0), _rwlock() |
ReadWriteSem::ReadWriteSem() : _rwlock() |
{ | { |
} | } |
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{ | { |
_rwlock._internal_lock.lock(); | _rwlock._internal_lock.lock(); |
} | } |
catch (IPCException &) |
catch (...) |
{ | { |
PEGASUS_ASSERT(0); | PEGASUS_ASSERT(0); |
} | } |
while (_readers.get() > 0 || _writers.get() > 0) |
while (_rwlock._readers.get() > 0 || _rwlock._writers.get() > 0) |
{ | { |
Threads::yield(); | Threads::yield(); |
} | } |
_rwlock._internal_lock.unlock(); | _rwlock._internal_lock.unlock(); |
} | } |
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//--------------------------------------------------------------------- |
void ReadWriteSem::waitRead() |
void ReadWriteSem::_wait(Boolean writeLock, ThreadType caller) |
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{ | { |
//----------------------------------------------------------------- |
// Lock the internal mutex to ensure only one waiter is processed at a time. |
// Lock this object to maintain integrity while we decide |
AutoMutex lock(_rwlock._internal_lock); |
// exactly what to do next. |
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//----------------------------------------------------------------- |
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_rwlock._internal_lock.lock(); |
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if (writeLock) |
// Wait for the existing writer (if any) to clear. |
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while (_rwlock._writers.get() > 0) |
{ | { |
//----------------------------------------------------------------- |
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// Write Lock Step 1: lock the object and allow all the readers to exit |
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//----------------------------------------------------------------- |
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while (_readers.get() > 0) |
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Threads::yield(); | Threads::yield(); |
//----------------------------------------------------------------- |
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// Write Lock Step 2: Obtain the Write Mutex |
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// Although there are no readers, there may be a writer |
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//----------------------------------------------------------------- |
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try |
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{ |
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_rwlock._wlock.lock(); |
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} | } |
catch (const IPCException&) |
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{ |
// Wait for a reader slot to open up. |
_rwlock._internal_lock.unlock(); |
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throw; |
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} |
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//----------------------------------------------------------------- |
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// Write Lock Step 3: set the writer count to one, unlock the object |
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// There are no readers and we are the only writer ! |
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//----------------------------------------------------------------- |
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_writers = 1; |
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// set the owner |
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_rwlock._owner = Threads::self(); |
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// unlock the object |
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_rwlock._internal_lock.unlock(); |
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} |
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else |
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{ |
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//----------------------------------------------------------------- |
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// Read Lock Step 1: Wait for the existing writer (if any) to clear |
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//----------------------------------------------------------------- |
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while (_writers.get() > 0) |
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Threads::yield(); |
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//----------------------------------------------------------------- |
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// Read Lock Step 2: wait for a reader slot to open up, then return |
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// At this point there are no writers, but there may be too many |
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// readers. |
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//----------------------------------------------------------------- |
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try |
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{ |
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_rwlock._rlock.wait(); | _rwlock._rlock.wait(); |
} |
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catch (const IPCException&) |
// Increment the number of readers. |
{ |
_rwlock._readers++; |
_rwlock._internal_lock.unlock(); |
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throw; |
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} |
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//----------------------------------------------------------------- |
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// Read Lock Step 3: increment the number of readers, unlock the object, |
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// return |
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//----------------------------------------------------------------- |
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_readers++; |
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_rwlock._internal_lock.unlock(); |
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} |
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} | } |
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void ReadWriteSem::_unlock(Boolean writeLock, ThreadType caller) |
void ReadWriteSem::waitWrite() |
{ |
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if (writeLock && _writers.get() != 0) |
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{ | { |
_writers = 0; |
// Lock the internal mutex to ensure only one waiter is processed at a time. |
_rwlock._wlock.unlock(); |
AutoMutex lock(_rwlock._internal_lock); |
} |
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else if (_readers.get() != 0) |
// Allow all the readers to exit. |
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while (_rwlock._readers.get() > 0) |
{ | { |
_readers--; |
Threads::yield(); |
_rwlock._rlock.signal(); |
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} | } |
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// Obtain the write mutex. |
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_rwlock._wlock.lock(); |
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// Set the writer count to one. |
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_rwlock._writers = 1; |
} | } |
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int ReadWriteSem::read_count() const |
void ReadWriteSem::unlockRead() |
{ | { |
return _readers.get(); |
PEGASUS_ASSERT(_rwlock._readers.get() > 0); |
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_rwlock._readers--; |
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_rwlock._rlock.signal(); |
} | } |
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int ReadWriteSem::write_count() const |
void ReadWriteSem::unlockWrite() |
{ | { |
return _writers.get(); |
PEGASUS_ASSERT(_rwlock._writers.get() == 1); |
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_rwlock._writers = 0; |
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_rwlock._wlock.unlock(); |
} | } |
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#endif /* !PEGASUS_USE_SEMAPHORE_RWLOCK */ | #endif /* !PEGASUS_USE_SEMAPHORE_RWLOCK */ |