Source code of Windows XP (NT5)
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/*==========================================================================
*
* Copyright (C) 1995 - 2000 Microsoft Corporation. All Rights Reserved.
*
* File: LockedContextFixedPool.h
* Content: fixed pool manager for classes that takes into account contexts
*
* History:
* Date By Reason
* ====== == ======
* 12-18-97 aarono Original
* 11-06-98 ejs Add custom handler for Release function
* 04-12-99 johnkan Trimmed unused functions and parameters, added size assert
* 01-31-2000 johnkan Added code to check for items already being in the pool on Release().
* 02-08-2000 johnkan Derived from ClassFPM.h
* 03-26-2000 johnkan Renamed to avoid collisions with other classes
* 04-06-2000 johnkan Modified to have a base class to derive pool items from
***************************************************************************/
#ifndef __LOCKED_CONTEXT_FIXED_POOL__
#define __LOCKED_CONTEXT_FIXED_POOL__
#undef DPF_SUBCOMP
#define DPF_SUBCOMP DN_SUBCOMP_COMMON
//**********************************************************************
// Constant definitions
//**********************************************************************
#define CHECK_FOR_DUPLICATE_LOCKED_CONTEXT_FPM_RELEASE
//**********************************************************************
// Macro definitions
//**********************************************************************
#ifndef OFFSETOF
// Macro to compute the offset of an element inside of a larger structure (copied from MSDEV's STDLIB.H)
#define OFFSETOF(s,m) ( (INT_PTR) &(((s *)0)->m) )
#define __LOCAL_OFFSETOF_DEFINED__
#endif // OFFSETOF
//**********************************************************************
// Structure definitions
//**********************************************************************
//
// forward reference
//
template< class S > class CLockedContextFixedPoolItem;
template< class T, class S > class CLockedContextFixedPool;
//**********************************************************************
// Variable definitions
//**********************************************************************
//**********************************************************************
// Function prototypes
//**********************************************************************
//**********************************************************************
// Class definitions
//**********************************************************************
//
// class to act as a link in the pool
//
template< class S >
class CLockedContextFixedPoolItem
{
public:
#undef DPF_MODNAME
#define DPF_MODNAME "CLockedContextFixedPoolItem::CLockedContextFixedPoolItem"
CLockedContextFixedPoolItem()
{
m_iRefCount = 0;
m_pNext = NULL;
}
#undef DPF_MODNAME
#define DPF_MODNAME "CLockedContextFixedPoolItem::~CLockedContextFixedPoolItem"
virtual ~CLockedContextFixedPoolItem() { DNASSERT( m_iRefCount == 0 ); }
#undef DPF_MODNAME
#define DPF_MODNAME "CLockedContextFixedPoolItem::AddRef"
void AddRef( void )
{
DNASSERT( m_iRefCount != -1 );
InterlockedIncrement( const_cast<LONG*>( &m_iRefCount ) );
}
#undef DPF_MODNAME
#define DPF_MODNAME "CLockedContextFixedPoolItem::DecRef"
void DecRef( void )
{
DNASSERT( m_iRefCount != 0 );
if ( InterlockedDecrement( const_cast<LONG*>( &m_iRefCount ) ) == 0 )
{
ReturnSelfToPool();
}
}
CLockedContextFixedPoolItem *GetNext( void ) const { return m_pNext; }
void InvalidateNext( void ) { m_pNext = NULL; }
#undef DPF_MODNAME
#define DPF_MODNAME "CLockedContextFixedPoolItem::LinkToPool"
void LinkToPool( CLockedContextFixedPoolItem *volatile *const ppPoolItems )
{
DNASSERT( ppPoolItems != NULL );
m_pNext = *ppPoolItems;
*ppPoolItems = this;
}
//
// Default initialization and deinitialization functions. These can
// be overridden by the derived classes.
//
virtual BOOL PoolAllocFunction( S Context ){ return TRUE; }
virtual BOOL PoolInitFunction( S Context ){ return TRUE; }
virtual void PoolReleaseFunction( void ){};
virtual void PoolDeallocFunction( void ){};
protected:
private:
//
// reference count used to return this item to the pool
//
volatile LONG m_iRefCount;
//
// pointer used to link this item to the rest of the pool
//
CLockedContextFixedPoolItem *m_pNext;
virtual void ReturnSelfToPool( void ) = 0;
//
// prevent unwarranted copies
//
CLockedContextFixedPoolItem< S >( const CLockedContextFixedPoolItem< S > & );
CLockedContextFixedPoolItem< S >& operator=( const CLockedContextFixedPoolItem< S > & );
};
//
// class to manage the pool
//
template< class T, class S >
class CLockedContextFixedPool
{
public:
CLockedContextFixedPool();
~CLockedContextFixedPool();
void Lock( void ) { DNEnterCriticalSection( &m_Lock ); }
void Unlock( void ) { DNLeaveCriticalSection( &m_Lock ); }
BOOL Initialize( void );
void Deinitialize( void );
T *Get( S Context );
void Release( T *const pItem );
protected:
private:
DNCRITICAL_SECTION m_Lock;
CLockedContextFixedPoolItem< S > *volatile m_pPool; // pointer to list of available elements
DEBUG_ONLY( BOOL m_fInitialized );
DEBUG_ONLY( volatile LONG m_lOutstandingItemCount );
T *RemoveNode( void )
{
T *pReturn;
if ( m_pPool != NULL )
{
pReturn = static_cast<T*>( m_pPool );
m_pPool = m_pPool->GetNext();
DEBUG_ONLY( pReturn->InvalidateNext() );
}
else
{
pReturn = NULL;
}
return pReturn;
}
//
// prevent unwarranted copies
//
CLockedContextFixedPool< T, S >( const CLockedContextFixedPool< T, S > & );
CLockedContextFixedPool< T, S >& operator=( const CLockedContextFixedPool< T, S > & );
};
//**********************************************************************
// Class function definitions
//**********************************************************************
//**********************************************************************
// ------------------------------
// CLockedContextFixedPool::CLockedContextFixedPool - constructor
//
// Entry: Nothing
//
// Exit: Nothing
// ------------------------------
template< class T, class S >
CLockedContextFixedPool< T, S >::CLockedContextFixedPool():
m_pPool( NULL )
{
DEBUG_ONLY( m_fInitialized = FALSE );
DEBUG_ONLY( m_lOutstandingItemCount = 0 );
}
//**********************************************************************
//**********************************************************************
// ------------------------------
// CLockedContextFixedPool::~CLockedContextFixedPool - destructor
//
// Entry: Nothing
//
// Exit: Nothing
// ------------------------------
template< class T, class S >
CLockedContextFixedPool< T, S >::~CLockedContextFixedPool()
{
DEBUG_ONLY( DNASSERT( m_lOutstandingItemCount == 0 ) );
DEBUG_ONLY( DNASSERT( m_fInitialized == FALSE ) );
}
//**********************************************************************
//**********************************************************************
// ------------------------------
// CLockedContextFixedPool::Initialize - initialize pool
//
// Entry: Nothing
// Pointer to function to call when a new entry is removed from the pool
// Pointer to function to call when an entry is returned to the pool
// Pointer to function to call when an entry is deallocated
//
// Exit: Boolean indicating success
// TRUE = initialization succeeded
// FALSE = initialization failed
// ------------------------------
template< class T, class S >
BOOL CLockedContextFixedPool< T, S >::Initialize( void )
{
BOOL fReturn;
DEBUG_ONLY( DNASSERT( m_fInitialized == FALSE ) );
fReturn = TRUE;
if ( DNInitializeCriticalSection( &m_Lock ) == FALSE )
{
fReturn = FALSE;
goto Exit;
}
DebugSetCriticalSectionRecursionCount( &m_Lock, 0 );
DEBUG_ONLY( m_fInitialized = TRUE );
Exit:
return fReturn;
}
//**********************************************************************
//**********************************************************************
// ------------------------------
// CLockedContextFixedPool::Deinitialize - deinitialize pool
//
// Entry: Nothing
//
// Exit: Nothing
// ------------------------------
template< class T, class S >
void CLockedContextFixedPool< T, S >::Deinitialize( void )
{
DEBUG_ONLY( DNASSERT( m_fInitialized != FALSE ) );
Lock();
DEBUG_ONLY( DNASSERT( m_lOutstandingItemCount == 0 ) );
while ( m_pPool != NULL )
{
CLockedContextFixedPoolItem< S > *pNode;
pNode = RemoveNode();
pNode->PoolDeallocFunction();
delete pNode;
}
Unlock();
DNDeleteCriticalSection( &m_Lock );
DEBUG_ONLY( m_fInitialized = FALSE );
}
//**********************************************************************
//**********************************************************************
// ------------------------------
// CLockedContextFixedPool::Get - get an item from the pool
//
// Entry: Pointer to user context
//
// Exit: Pointer to item
// NULL = out of memory
// ------------------------------
template< class T, class S >
T *CLockedContextFixedPool< T, S >::Get( S Context )
{
T *pReturn;
DEBUG_ONLY( DNASSERT( m_fInitialized != FALSE ) );
//
// initialize
//
pReturn = NULL;
Lock();
//
// if the pool is empty, try to allocate a new entry, otherwise grab
// the first item from the pool
//
if ( m_pPool == NULL )
{
Unlock();
pReturn = new T;
if ( pReturn != NULL )
{
if ( pReturn->PoolAllocFunction( Context ) == FALSE )
{
delete pReturn;
pReturn = NULL;
}
}
}
else
{
pReturn = RemoveNode();
Unlock();
}
//
// if we have an entry (it was freshly created, or removed from the pool),
// attempt to initialize it before passing it to the user
//
if ( pReturn != NULL )
{
if ( pReturn->PoolInitFunction( Context ) == FALSE )
{
Lock();
pReturn->LinkToPool( &m_pPool );
Unlock();
pReturn = NULL;
}
else
{
pReturn->SetOwningPool( this );
pReturn->AddRef();
DEBUG_ONLY( InterlockedIncrement( const_cast<LONG*>( &m_lOutstandingItemCount ) ) );
}
}
return pReturn;
}
//**********************************************************************
//**********************************************************************
// ------------------------------
// CLockedContextFixedPool::Release - return item to pool
//
// Entry: Pointer to item
//
// Exit: Nothing
// ------------------------------
template< class T, class S >
void CLockedContextFixedPool< T, S >::Release( T *const pItem )
{
DEBUG_ONLY( DNASSERT( m_fInitialized != FALSE ) );
DNASSERT( pItem != NULL );
DEBUG_ONLY( DNASSERT( pItem->GetNext() == NULL ) );
pItem->PoolReleaseFunction();
Lock();
#if defined(CHECK_FOR_DUPLICATE_LOCKED_CONTEXT_FPM_RELEASE) && defined(DEBUG)
{
CLockedContextFixedPoolItem< S > *pTemp;
pTemp = m_pPool;
while ( pTemp != NULL )
{
DNASSERT( pTemp != pItem );
pTemp = pTemp->GetNext();
}
}
#endif // CHECK_FOR_DUPLICATE_LOCKED_CONTEXT_FPM_RELEASE
DEBUG_ONLY( pItem->SetOwningPool( NULL ) );
#ifdef NO_POOLS
pItem->PoolDeallocFunction();
delete pItem;
#else
pItem->LinkToPool( &m_pPool );
#endif
Unlock();
DEBUG_ONLY( InterlockedDecrement( const_cast<LONG*>( &m_lOutstandingItemCount ) ) );
}
//**********************************************************************
#ifdef __LOCAL_OFFSETOF_DEFINED__
#undef __LOCAL_OFFSETOF_DEFINED__
#undef OFFSETOF
#endif // __LOCAL_OFFSETOF_DEFINED__
#undef DPF_SUBCOMP
#undef DPF_MODNAME
#endif // __LOCKED_CONTEXT_FIXED_POOL__