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//+-----------------------------------------------------------------------
//
// File: resource.hxx
//
// Contents: CResource, CReadLock, CWriteLock,
// CSafeReadLock, CSafeWriteLock.
//
//
// History: 8 Mar 93 WadeR Created.
// 08-Jul-93 WadeR Moved from security to common
// 18-Nov-93 WadeR Made inline, added Safe locks
//
//------------------------------------------------------------------------
#ifndef _INC_RESOURCE_HXX_
#define _INC_RESOURCE_HXX_
extern "C"
{
#include <nt.h>
#include <ntrtl.h>
#include <nturtl.h>
}
#include <except.hxx>
//+-----------------------------------------------------------------
//
// Class: CResource
//
// Purpose: Allows multiple readers or single writer at a resource.
//
// Interface: [CResource] --
// [~CResource] --
// [GetRead] --
// [GetWrite] --
// [ReadToWrite] --
// [WriteToRead] --
// [Release] --
//
// History: 24-Feb-93 WadeR Created.
//
// Notes: This wrapper will allow starving writers, since it just
// passes everything through to the RTL Resource code, which
// allows starving writers.
//
//------------------------------------------------------------------
class CResource
{
RTL_RESOURCE _rResource;
public:
CResource();
~CResource();
void Release();
void GetRead();
void GetWrite();
void ReadToWrite();
void WriteToRead();
};
inline
CResource::CResource()
{
RtlInitializeResource( &_rResource );
}
inline
CResource::~CResource()
{
RtlDeleteResource( &_rResource );
}
inline
void CResource::Release()
{
RtlReleaseResource( &_rResource );
}
inline
void CResource::GetRead()
{
RtlAcquireResourceShared( &_rResource, TRUE );
}
inline
void CResource::GetWrite()
{
RtlAcquireResourceExclusive( &_rResource, TRUE );
}
inline
void CResource::ReadToWrite()
{
RtlConvertSharedToExclusive( &_rResource );
}
inline
void CResource::WriteToRead()
{
RtlConvertExclusiveToShared( &_rResource );
}
//+---------------------------------------------------------------------------
//
// Class: CReadLock
//
// Purpose: Lock using a Resource monitor
//
// History: 24-Feb-93 WadeR Created.
//
// Notes: Simple lock object to be created on the stack.
// The constructor acquires the resource, the destructor
// (called when lock is going out of scope) releases it.
//
//----------------------------------------------------------------------------
class CReadLock
{
public:
CReadLock ( CResource& r ) : _r(r)
{ _r.GetRead(); };
~CReadLock ()
{ _r.Release(); };
private:
CResource& _r;
};
//+---------------------------------------------------------------------------
//
// Class: CWriteLock
//
// Purpose: Lock using a Resource monitor
//
// History: 24-Feb-93 WadeR Created.
//
// Notes: Simple lock object to be created on the stack.
// The constructor acquires the resource, the destructor
// (called when lock is going out of scope) releases it.
//
//----------------------------------------------------------------------------
class CWriteLock
{
public:
CWriteLock ( CResource& r ) : _r(r)
{ _r.GetWrite(); };
~CWriteLock ()
{ _r.Release(); };
private:
CResource& _r;
};
//+---------------------------------------------------------------------------
//
// Class: CSafeReadLock
//
// Purpose: Exception safe lock using a Resource monitor
//
// History: 24-Feb-93 WadeR Created.
//
// Notes: Simple lock object to be created on the stack.
// The constructor acquires the resource, the destructor
// (called when lock is going out of scope) releases it.
//
//----------------------------------------------------------------------------
class CSafeReadLock : INHERIT_UNWIND
{
INLINE_UNWIND(CSafeReadLock);
public:
CSafeReadLock ( CResource& r ) : _r(r)
{ _r.GetRead(); END_CONSTRUCTION (CSafeReadLock); };
~CSafeReadLock ()
{ _r.Release(); };
private:
CResource& _r;
};
//+---------------------------------------------------------------------------
//
// Class: CSafeWriteLock
//
// Purpose: Exception safe lock using a Resource monitor
//
// History: 24-Feb-93 WadeR Created.
//
// Notes: Simple lock object to be created on the stack.
// The constructor acquires the resource, the destructor
// (called when lock is going out of scope) releases it.
//
//----------------------------------------------------------------------------
class CSafeWriteLock : INHERIT_UNWIND
{
INLINE_UNWIND(CSafeWriteLock);
public:
CSafeWriteLock ( CResource& r ) : _r(r)
{ _r.GetWrite(); END_CONSTRUCTION (CSafeWriteLock); };
~CSafeWriteLock ()
{ _r.Release(); };
private:
CResource& _r;
};
#endif // _INC_RESOURCE_HXX_
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