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fixed SF# 1896482: tryReadLock intermittent error

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This commit is contained in:
Guenter Obiltschnig
2008-09-17 19:13:50 +00:00
parent cf1d1fa952
commit c83f8e2434
3 changed files with 31 additions and 9 deletions
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3
Foundation/include/Poco/RWLock_WIN32.h
View File

@@ -1,7 +1,7 @@
//
// RWLock_WIN32.h
//
// $Id: //poco/svn/Foundation/include/Poco/RWLock_WIN32.h#2 $
// $Id: //poco/1.3/Foundation/include/Poco/RWLock_WIN32.h#3 $
//
// Library: Foundation
// Package: Threading
@@ -67,6 +67,7 @@ private:
HANDLE _readEvent;
HANDLE _writeEvent;
unsigned _readers;
unsigned _writersWaiting;
unsigned _writers;
};

21
Foundation/src/RWLock_WIN32.cpp
View File

@@ -1,7 +1,7 @@
//
// RWLock_WIN32.cpp
//
// $Id: //poco/svn/Foundation/src/RWLock_WIN32.cpp#2 $
// $Id: //poco/1.3/Foundation/src/RWLock_WIN32.cpp#3 $
//
// Library: Foundation
// Package: Threading
@@ -40,7 +40,7 @@
namespace Poco {
RWLockImpl::RWLockImpl(): _readers(0), _writers(0)
RWLockImpl::RWLockImpl(): _readers(0), _writersWaiting(0), _writers(0)
{
_mutex = CreateMutexW(NULL, FALSE, NULL);
if (_mutex == NULL)
@@ -69,7 +69,7 @@ inline void RWLockImpl::addWriter()
switch (WaitForSingleObject(_mutex, INFINITE))
{
case WAIT_OBJECT_0:
if (++_writers == 1) ResetEvent(_readEvent);
if (++_writersWaiting == 1) ResetEvent(_readEvent);
ReleaseMutex(_mutex);
break;
default:
@@ -83,7 +83,7 @@ inline void RWLockImpl::removeWriter()
switch (WaitForSingleObject(_mutex, INFINITE))
{
case WAIT_OBJECT_0:
if (--_writers == 0) SetEvent(_readEvent);
if (--_writersWaiting == 0 && _writers == 0) SetEvent(_readEvent);
ReleaseMutex(_mutex);
break;
default:
@@ -104,6 +104,7 @@ void RWLockImpl::readLockImpl()
++_readers;
ResetEvent(_writeEvent);
ReleaseMutex(_mutex);
poco_assert_dbg(_writers == 0);
break;
default:
throw SystemException("cannot lock reader/writer lock");
@@ -123,6 +124,7 @@ bool RWLockImpl::tryReadLockImpl()
++_readers;
ResetEvent(_writeEvent);
ReleaseMutex(_mutex);
poco_assert_dbg(_writers == 0);
return true;
case WAIT_TIMEOUT:
return false;
@@ -142,11 +144,13 @@ void RWLockImpl::writeLockImpl()
{
case WAIT_OBJECT_0:
case WAIT_OBJECT_0 + 1:
--_writers;
--_writersWaiting;
++_readers;
++_writers;
ResetEvent(_readEvent);
ResetEvent(_writeEvent);
ReleaseMutex(_mutex);
poco_assert_dbg(_writers == 1);
break;
default:
removeWriter();
@@ -165,11 +169,13 @@ bool RWLockImpl::tryWriteLockImpl()
{
case WAIT_OBJECT_0:
case WAIT_OBJECT_0 + 1:
--_writers;
--_writersWaiting;
++_readers;
++_writers;
ResetEvent(_readEvent);
ResetEvent(_writeEvent);
ReleaseMutex(_mutex);
poco_assert_dbg(_writers == 1);
return true;
case WAIT_TIMEOUT:
removeWriter();
@@ -186,7 +192,8 @@ void RWLockImpl::unlockImpl()
switch (WaitForSingleObject(_mutex, INFINITE))
{
case WAIT_OBJECT_0:
if (_writers == 0) SetEvent(_readEvent);
_writers = 0;
if (_writersWaiting == 0) SetEvent(_readEvent);
if (--_readers == 0) SetEvent(_writeEvent);
ReleaseMutex(_mutex);
break;

16
Foundation/testsuite/src/RWLockTest.cpp
View File

@@ -1,7 +1,7 @@
//
// RWLockTest.cpp
//
// $Id: //poco/svn/Foundation/testsuite/src/RWLockTest.cpp#2 $
// $Id: //poco/1.3/Foundation/testsuite/src/RWLockTest.cpp#2 $
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
@@ -60,13 +60,20 @@ public:
for (int k = 0; k < 100; ++k)
{
if (_counter != lastCount) _ok = false;
Thread::yield();
}
_lock.unlock();
_lock.writeLock();
for (int k = 0; k < 100; ++k)
{
--_counter;
Thread::yield();
}
for (int k = 0; k < 100; ++k)
{
++_counter;
Thread::yield();
}
++_counter;
if (_counter <= lastCount) _ok = false;
_lock.unlock();
@@ -102,13 +109,20 @@ public:
for (int k = 0; k < 100; ++k)
{
if (_counter != lastCount) _ok = false;
Thread::yield();
}
_lock.unlock();
while (!_lock.tryWriteLock()) Thread::yield();
for (int k = 0; k < 100; ++k)
{
--_counter;
Thread::yield();
}
for (int k = 0; k < 100; ++k)
{
++_counter;
Thread::yield();
}
++_counter;
if (_counter <= lastCount) _ok = false;
_lock.unlock();