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// **********************************************************************
//
// Copyright (c) 2003-2011 ZeroC, Inc. All rights reserved.
//
// This copy of Ice is licensed to you under the terms described in the
// ICE_LICENSE file included in this distribution.
//
// **********************************************************************
//
// We disable deprecation warning here, to allow clean compilation of
// of deprecated methods.
//
#ifdef _MSC_VER
# pragma warning( disable : 4996 )
#endif
#include <IceUtil/StaticMutex.h>
#include <IceUtil/ThreadException.h>
#ifdef _WIN32
# include <list>
# include <algorithm>
using namespace std;
static CRITICAL_SECTION _criticalSection;
//
// Although apparently not documented by Microsoft, static objects are
// initialized before DllMain/DLL_PROCESS_ATTACH and finalized after
// DllMain/DLL_PROCESS_DETACH ... However, note that after the DLL is
// detached the allocated StaticMutexes may still be accessed. See
// http://blogs.msdn.com/larryosterman/archive/2004/06/10/152794.aspx
// for some details. This means that there is no convenient place to
// cleanup the globally allocated static mutexes.
//
namespace IceUtil
{
class Init
{
public:
Init();
};
static Init _init;
Init::Init()
{
InitializeCriticalSection(&_criticalSection);
}
}
void IceUtil::StaticMutex::initialize() const
{
//
// Yes, a double-check locking. It should be safe since we use memory barriers
// (through InterlockedCompareExchangePointer) in both reader and writer threads
//
EnterCriticalSection(&_criticalSection);
//
// The second check
//
if(_mutex == 0)
{
CRITICAL_SECTION* newMutex = new CRITICAL_SECTION;
InitializeCriticalSection(newMutex);
//
// _mutex is written after the new initialized CRITICAL_SECTION/Mutex
//
void* oldVal = InterlockedCompareExchangePointer(reinterpret_cast<void**>(&_mutex), newMutex, 0);
assert(oldVal == 0);
}
LeaveCriticalSection(&_criticalSection);
}
bool
IceUtil::StaticMutex::initialized() const
{
//
// Read mutex and then inserts a memory barrier to ensure we can't
// see tmp != 0 before we see the initialized object
//
void* tmp = _mutex;
return InterlockedCompareExchangePointer(reinterpret_cast<void**>(&tmp), 0, 0) != 0;
}
void
IceUtil::StaticMutex::lock() const
{
if(!initialized())
{
initialize();
}
EnterCriticalSection(_mutex);
assert(_mutex->RecursionCount == 1);
}
bool
IceUtil::StaticMutex::tryLock() const
{
if(!initialized())
{
initialize();
}
if(!TryEnterCriticalSection(_mutex))
{
return false;
}
if(_mutex->RecursionCount > 1)
{
LeaveCriticalSection(_mutex);
throw ThreadLockedException(__FILE__, __LINE__);
}
return true;
}
void
IceUtil::StaticMutex::unlock() const
{
assert(_mutex != 0);
assert(_mutex->RecursionCount == 1);
LeaveCriticalSection(_mutex);
}
void
IceUtil::StaticMutex::unlock(LockState&) const
{
assert(_mutex != 0);
assert(_mutex->RecursionCount == 1);
LeaveCriticalSection(_mutex);
}
void
IceUtil::StaticMutex::lock(LockState&) const
{
if(!initialized())
{
initialize();
}
EnterCriticalSection(_mutex);
}
#else
void
IceUtil::StaticMutex::lock() const
{
int rc = pthread_mutex_lock(&_mutex);
if(rc != 0)
{
if(rc == EDEADLK)
{
throw ThreadLockedException(__FILE__, __LINE__);
}
else
{
throw ThreadSyscallException(__FILE__, __LINE__, rc);
}
}
}
bool
IceUtil::StaticMutex::tryLock() const
{
int rc = pthread_mutex_trylock(&_mutex);
if(rc != 0 && rc != EBUSY)
{
if(rc == EDEADLK)
{
throw ThreadLockedException(__FILE__, __LINE__);
}
else
{
throw ThreadSyscallException(__FILE__, __LINE__, rc);
}
}
return (rc == 0);
}
void
IceUtil::StaticMutex::unlock() const
{
int rc = pthread_mutex_unlock(&_mutex);
if(rc != 0)
{
throw ThreadSyscallException(__FILE__, __LINE__, rc);
}
}
void
IceUtil::StaticMutex::unlock(LockState& state) const
{
state.mutex = &_mutex;
}
void
IceUtil::StaticMutex::lock(LockState&) const
{
}
#endif
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