windows-xp/Source/XPSP1/NT/ds/security/passport/atlmfc/atlcache.h

// This is a part of the Active Template Library.
// Copyright (C) 1996-2001 Microsoft Corporation
// All rights reserved.
//
// This source code is only intended as a supplement to the
// Active Template Library Reference and related
// electronic documentation provided with the library.
// See these sources for detailed information regarding the
// Active Template Library product.

#ifndef __ATLCACHE_H__
#define __ATLCACHE_H__

#pragma once

#include <atltime.h>
#include <atlutil.h>
#include <atlcoll.h>
#include <atlperf.h>
#include <atlcom.h>
#include <atlstr.h>
#include <atlsrvres.h>
#include <atldbcli.h>

#pragma warning (push)
#ifndef _ATL_NO_PRAGMA_WARNINGS
#pragma warning(disable: 4511) // copy constructor could not be generated
#pragma warning(disable: 4512) // assignment operator could not be generated
#endif //!_ATL_NO_PRAGMA_WARNINGS

#ifndef _CPPUNWIND
#pragma warning(disable: 4702) // unreachable code
#endif

namespace ATL {

//forward declarations;
class CStdStatClass;
class CPerfStatClass;

typedef struct __CACHEITEM
{
} *HCACHEITEM;

//Implementation of a cache that stores pointers to void
extern "C" __declspec(selectany) IID IID_IMemoryCacheClient = {0xb721b49d, 0xbb57, 0x47bc, { 0xac, 0x43, 0xa8, 0xd4, 0xc0, 0x7d, 0x18, 0x3d } };
extern "C" __declspec(selectany) IID IID_IMemoryCache = { 0x9c6cfb46, 0xfbde, 0x4f8b, { 0xb9, 0x44, 0x2a, 0xa0, 0x5d, 0x96, 0xeb, 0x5c } };
extern "C" __declspec(selectany) IID IID_IMemoryCacheControl = { 0x7634b28b, 0xd819, 0x409d, { 0xb9, 0x6e, 0xfc, 0x9f, 0x3a, 0xba, 0x32, 0x9f } };
extern "C" __declspec(selectany) IID IID_IMemoryCacheStats = { 0xd4b6df2d, 0x4bc0, 0x4734, { 0x8a, 0xce, 0xb7, 0x3a, 0xb, 0x97, 0x59, 0x56 } };

__interface ATL_NO_VTABLE __declspec(uuid("b721b49d-bb57-47bc-ac43-a8d4c07d183d")) 
    IMemoryCacheClient : public IUnknown
{
    // IMemoryCacheClient methods
    STDMETHOD( Free )(const void *pvData);
};

__interface ATL_NO_VTABLE __declspec(uuid("9c6cfb46-fbde-4f8b-b944-2aa05d96eb5c")) 
    IMemoryCache : public IUnknown
{
    // IMemoryCache Methods
    STDMETHOD(Add)(LPCSTR szKey, void *pvData, DWORD dwSize, 
                FILETIME *pftExpireTime,
                HINSTANCE hInstClient, HCACHEITEM *phEntry,
                IMemoryCacheClient *pClient);

    STDMETHOD(LookupEntry)(LPCSTR szKey, HCACHEITEM * phEntry);
    STDMETHOD(GetData)(const HCACHEITEM hEntry, void **ppvData, DWORD *pdwSize) const;
    STDMETHOD(ReleaseEntry)(const HCACHEITEM hEntry);
    STDMETHOD(RemoveEntry)(const HCACHEITEM hEntry);
    STDMETHOD(RemoveEntryByKey)(LPCSTR szKey);

    STDMETHOD(Flush)();
};

__interface ATL_NO_VTABLE __declspec(uuid("7634b28b-d819-409d-b96e-fc9f3aba329f")) 
    IMemoryCacheControl : public IUnknown
{
    // IMemoryCacheControl Methods
    STDMETHOD(SetMaxAllowedSize)(DWORD dwSize);
    STDMETHOD(GetMaxAllowedSize)(DWORD *pdwSize);
    STDMETHOD(SetMaxAllowedEntries)(DWORD dwSize);
    STDMETHOD(GetMaxAllowedEntries)(DWORD *pdwSize);
    STDMETHOD(ResetCache)();
};

__interface ATL_NO_VTABLE __declspec(uuid("d4b6df2d-4bc0-4734-8ace-b73a0b975956")) 
    IMemoryCacheStats : public IUnknown
{
    // IMemoryCacheStats Methods
    STDMETHOD(ClearStats)();
    STDMETHOD(GetHitCount)(DWORD *pdwSize);
    STDMETHOD(GetMissCount)(DWORD *pdwSize);
    STDMETHOD(GetCurrentAllocSize)(DWORD *pdwSize);
    STDMETHOD(GetMaxAllocSize)(DWORD *pdwSize);
    STDMETHOD(GetCurrentEntryCount)(DWORD *pdwSize);
    STDMETHOD(GetMaxEntryCount)(DWORD *pdwSize);

};

struct DLL_CACHE_ENTRY
{
    HINSTANCE hInstDll;
    DWORD dwRefs;
    BOOL bAlive;
    CHAR szDllName[_MAX_PATH];
};

inline bool operator==(const DLL_CACHE_ENTRY& entry1, const DLL_CACHE_ENTRY& entry2)
{
    return (entry1.hInstDll == entry2.hInstDll);
}

//
// IDllCache
// An interface that is used to load and unload Dlls.
//
__interface ATL_NO_VTABLE __declspec(uuid("A12478AB-D261-42f9-B525-7589143C1C97")) 
    IDllCache : public IUnknown
{
    // IDllCache methods
    virtual HINSTANCE Load(LPCSTR szFileName, void *pPeerInfo);
    virtual BOOL Free(HINSTANCE hInstance);
    virtual BOOL AddRefModule(HINSTANCE hInstance);
    virtual BOOL ReleaseModule(HINSTANCE hInstance);
    virtual HRESULT GetEntries(DWORD dwCount, DLL_CACHE_ENTRY *pEntries, DWORD *pdwCopied);
    virtual HRESULT Flush();
};

#ifndef ATL_CACHE_KEY_LENGTH
#define ATL_CACHE_KEY_LENGTH 128
#endif

typedef CFixedStringT<CStringA, ATL_CACHE_KEY_LENGTH> CFixedStringKey;

// No flusher -- only expired entries will be removed from the cache
// Also gives the skeleton for all of the flushers
class CNoFlusher
{
public:
    struct CCacheData
    {
    };
    
    void Add(CCacheData * /*pItem*/) { }
    void Remove(CCacheData * /*pItem*/) { }
    void Access(CCacheData * /*pItem*/) { }
    CCacheData * GetStart() const { return NULL; }
    CCacheData * GetNext(CCacheData * /*pCur*/) const { return NULL; }
};

// Old flusher -- oldest items are flushed first
class COldFlusher
{
public:
    struct CCacheData
    {
        CCacheData * pNext;
        CCacheData * pPrev;
    };

    CCacheData * pHead;
    CCacheData * pTail;

    COldFlusher() : pHead(NULL), pTail(NULL)
    {
    }

    // Add it to the tail of the list
    void Add(CCacheData * pItem)
    {
        ATLASSERT(pItem);

        pItem->pNext = NULL;
        pItem->pPrev = pTail;
        if (pHead)
        {
            pTail->pNext = pItem;
            pTail = pItem;
        }
        else
        {
            pHead = pItem;
            pTail = pItem;
        }
    }

    void Remove(CCacheData * pItem)
    {
        ATLASSERT(pItem);

        CCacheData * pPrev = pItem->pPrev;
        CCacheData * pNext = pItem->pNext;

        if (pPrev)
            pPrev->pNext = pNext;
        else
            pHead = pNext;

        if (pNext)
            pNext->pPrev = pPrev;
        else
            pTail = pPrev;

    }

    void Access(CCacheData * /*pItem*/)
    {
    }

    void Release(CCacheData * /*pItem*/)
    {
    }

    CCacheData * GetStart() const
    {
        return pHead;
    }

    CCacheData * GetNext(CCacheData * pCur) const
    {
        if (pCur != NULL)
            return pCur->pNext;
        else
            return NULL;
    }
};

// Least recently used flusher -- the item that was accessed the longest time ago is flushed
class CLRUFlusher : public COldFlusher
{
public:
    // Move it to the tail of the list
    void Access(CCacheData * pItem)
    {
        ATLASSERT(pItem);

        Remove(pItem);
        Add(pItem);
    }
};

// Least often used flusher
class CLOUFlusher : public COldFlusher
{
public:
    struct CCacheData : public COldFlusher::CCacheData
    {
        DWORD dwAccessed;
    };

    CCacheData * pHead;
    CCacheData * pTail;

    // Adds to the tail of the list
    void Add(CCacheData * pItem)
    {
        ATLASSERT(pItem);
        pItem->dwAccessed = 1;
        COldFlusher::Add(pItem);
    }

    void Access(CCacheData * pItem)
    {
        ATLASSERT(pItem);
        pItem->dwAccessed++;

        CCacheData * pMark = static_cast<CCacheData *>(pItem->pPrev);
        if (!pMark)   // The item is already at the head
            return;

        if (pMark->dwAccessed >= pItem->dwAccessed) // The element before it has
            return;                                 // been accessed more times

        Remove(pItem);

        while (pMark && (pItem->dwAccessed < pMark->dwAccessed))
            pMark = static_cast<CCacheData *>(pMark->pPrev);

        // pMark points to the first element that has been accessed more times,
        // so add pItem after pMark
        if (pMark)
        {
            CCacheData *pNext = static_cast<CCacheData *>(pMark->pNext);
            pMark->pNext = pItem;
            pItem->pPrev = pMark;

            pItem->pNext = pNext;
            pNext->pPrev = pItem;
        }
        else // Ran out of items -- put it on the head
        {
            pItem->pNext = pHead;
            pItem->pPrev = NULL;
            if (pHead)
                pHead->pPrev = pItem;
            else // the list was empty
                pTail = pItem;
            pHead = pItem;
        }
    }

    // We start at the tail and move forward for this flusher
    CCacheData * GetStart() const
    {
        return pTail;
    }

    CCacheData * GetNext(CCacheData * pCur) const
    {
        if (pCur != NULL)
            return static_cast<CCacheData *>(pCur->pPrev);
        else
            return NULL;
    }

};

template <class CFirst, class CSecond>
class COrFlushers : public CFirst, public CSecond
{
    struct CCacheData : public CFirst::CCacheData, CSecond::CCacheData
    {
    };

    BOOL m_bWhich;
    COrFlushers() : CFirst(), CSecond()
    {
        m_bWhich = FALSE;
    }

    BOOL Switch()
    {
        m_bWhich = !m_bWhich;
        return m_bWhich;
    }

    void Add(CCacheData * pItem) 
    {
        ATLASSERT(pItem);
        CFirst::Add(pItem);
        CSecond::Add(pItem);
    }

    void Remove(CCacheData * pItem) 
    {
        ATLASSERT(pItem);
        CFirst::Remove(pItem);
        CSecond::Remove(pItem);
    }

    void Access(CCacheData * pItem) 
    {
        ATLASSERT(pItem);
        CFirst::Access(pItem);
        CSecond::Access(pItem);
    }
    void Release(CCacheData * pItem)
    {
        ATLASSERT(pItem);
        CFirst::Release(pItem);
        CSecond::Release(pItem);
    }

    CCacheData * GetStart() const 
    { 
        if (bWhich)
            return static_cast<CCacheData *>(CFirst::GetStart());
        else
            return static_cast<CCacheData *>(CSecond::GetStart());
    }

    CCacheData * GetNext(CCacheData * pCur) const 
    { 
        if (bWhich)
            return static_cast<CCacheData *>(CFirst::GetNext(pCur));
        else
            return static_cast<CCacheData *>(CSecond::GetNext(pCur));
    }
};

class CNoExpire
{
public:
    struct CCacheData
    {
    };

    void Add(CCacheData * /*pItem*/) { }
    void Commit(CCacheData * /*pItem*/) { }
    void Access(CCacheData * /*pItem*/) { }
    void Remove(CCacheData * /*pItem*/) { }
    void Start() { }
    BOOL IsExpired(CCacheData * /*pItem*/) { return FALSE; }
    CCacheData * GetExpired() { return NULL; }
};

class CExpireCuller
{
public:
    struct CCacheData
    {
        CFileTime cftExpireTime;
        CCacheData * pNext;
        CCacheData * pPrev;
    };

    CFileTime m_cftCurrent;
    CCacheData *pHead;
    CCacheData *pTail;

    CExpireCuller()
    {
        pHead = NULL;
        pTail = NULL;
    }

    // Element is being added -- perform necessary initialization
    void Add(CCacheData * pItem)
    {
        pItem;
        ATLASSERT(pItem);
    }

    // Expiration data has been set -- add to main list
    // Head is the first item to expire
    // a FILETIME of 0 indicates that the item should never expire
    void Commit(CCacheData * pItem)
    {
        ATLASSERT(pItem);
        if (!pHead)
        {
            pHead = pItem;
            pTail = pItem;
            pItem->pNext = NULL;
            pItem->pPrev = NULL;
            return;
        }

        if (CFileTime(pItem->cftExpireTime) == 0)
        {
            pTail->pNext = pItem;
            pItem->pPrev = pTail;
            pItem->pNext = NULL;
            pTail = pItem;
            return;
        }

        CCacheData * pMark = pHead;
        while (pMark && (pMark->cftExpireTime < pItem->cftExpireTime))
            pMark = pMark->pNext;

        if (pMark) // An entry was found that expires after the added entry
        {
            CCacheData *pPrev = pMark->pPrev;
            if (pPrev)
                pPrev->pNext = pItem;
            else
                pHead = pItem;

            pItem->pNext = pMark;
            pItem->pPrev = pPrev;
            pMark->pPrev = pItem;
        }
        else // Ran out of items -- put it on the tail
        {
            if (pTail)
                pTail->pNext = pItem;
            pItem->pPrev = pTail;
            pItem->pNext = NULL;
            pTail = pItem;
        }
    }

    void Access(CCacheData * /*pItem*/)
    {
    }

    void Release(CCacheData * /*pItem*/)
    {
    }

    void Remove(CCacheData * pItem)
    {
        ATLASSERT(pItem);
        CCacheData *pPrev = pItem->pPrev;
        CCacheData *pNext = pItem->pNext;
        
        if (pPrev)
            pPrev->pNext = pNext;
        else
            pHead = pNext;

        if (pNext)
            pNext->pPrev = pPrev;
        else
            pTail = pPrev;

    }

    // About to start culling
    void Start()
    {
        m_cftCurrent = CFileTime::GetCurrentTime();
    }

    BOOL IsExpired(CCacheData *pItem)
    {
        if ((pItem->cftExpireTime != 0) && 
            m_cftCurrent > pItem->cftExpireTime)
            return TRUE;

        return FALSE;
    }

    // Get the next expired entry
    CCacheData * GetExpired()
    {
        if (!pHead)
            return NULL;
        if (IsExpired(pHead))
            return pHead;

        return NULL;
    }
};

class CLifetimeCuller : public CExpireCuller
{
public:
    struct CCacheData : public CExpireCuller::CCacheData
    {
        ULONGLONG nLifespan;
    };

    void Add(CCacheData * pItem)
    {
        ATLASSERT(pItem);
        pItem->nLifespan = 0;
        CExpireCuller::Add(pItem);
    }

    void Commit(CCacheData * pItem)
    {        
        ATLASSERT(pItem);
        if (pItem->nLifespan == 0)
            pItem->cftExpireTime = 0;
        else
            pItem->cftExpireTime = CFileTime(CFileTime::GetCurrentTime().GetTime() + pItem->nLifespan);
        CExpireCuller::Commit(pItem);
    }

    void Access(CCacheData * pItem)
    {
        ATLASSERT(pItem);
        CExpireCuller::Remove(pItem);
        Commit(pItem);
    }

    CCacheData * GetExpired() 
    { 
        return static_cast<CCacheData *>(CExpireCuller::GetExpired());
    }
};

template <__int64 ftLifespan>
class CFixedLifetimeCuller : public CExpireCuller
{
public:
    void Commit(CCacheData * pItem)
    {
        ATLASSERT(pItem);

        if (ftLifespan == 0)
            pItem->cftExpireTime = 0;
        else
            pItem->cftExpireTime = CFileTime::GetCurrentTime() + CFileTimeSpan(ftLifespan);

        CExpireCuller::Commit(pItem);
    }

    void Access(CCacheData * pItem)
    {
        ATLASSERT(pItem);
        CExpireCuller::Remove(pItem);
        Commit(pItem);
    }

    CCacheData * GetExpired() 
    { 
        return static_cast<CCacheData *>(CExpireCuller::GetExpired());
    }
};


template <class CFirst, class CSecond>
class OrCullers : public CFirst, public CSecond
{
    struct CCacheData : public CFirst::CCacheData, public CSecond::CCacheData
    {
    };

    void Add(CCacheData * pItem)
    {
        CFirst::Add(pItem);
        CSecond::Add(pItem);
    }

    void Access(CCacheData * pItem)
    {
        CFirst::Access(pItem);
        CSecond::Access(pItem);
    }

    void Remove(CCacheData * pItem)
    {
        CFirst::Remove(pItem);
        CSecond::Remove(pItem);
    }

    void Start(CCacheData * pItem)
    {
        CFirst::Start(pItem);
        CSecond::Start(pItem);
    }

    CCacheData * GetExpired() 
    { 
        CCacheData *pItem = static_cast<CCacheData *>(CFirst::GetExpired());
        if (!pItem)
            pItem = static_cast<CCacheData *>(CSecond::GetExpired());

        return pItem;
    }

    BOOL IsExpired(CCacheData * pItem)
    {
        return (CFirst::IsExpired(pItem) || CSecond::IsExpired(pItem))
    }
};

//
//CMemoryCacheBase
// Description:
//  This class provides the implementation of a generic cache that stores
//  elements in memory. CMemoryCacheBase uses the CCacheDataBase generic
//  cache element structure to hold items in the cache. The cache is
//  implemented using the CAtlMap map class. CMemoryCache uses a wide
//  character string as it's Key type to identify entries. Entries must
//  have unique key values. If you try to add an entry with a key that
//  is exactly the same as an existing key, the existing entry will be
//  overwritten.
//
// Template Parameters:
//  T: The class that inherits from this class. This class must implement
//     void OnDestroyEntry(NodeType *pEntry);
//  DataType: Specifies the type of the element to be stored in the memory
//            cache such as CString or void*
//  NodeInfo: Specifies any additional data that should be stored in each item
//            in the cache
//  keyType, keyTrait : specifies the key type and traits (see CAtlMap)
//  Flusher : the class responsible for determining which data should be flushed
//            when the cache is at a configuration limit
//  Culler  : the class responsible for determining which data should be removed
//            from the cache due to expiration
//  SyncClass:Specifies the class that will be used for thread synchronization
//            when accessing the cache. The class interface for SyncClass must
//            be identical to that of CComCriticalSection (see atlbase.h)
//  StatClass: Class used to contain statistics about this cache.
// REVIEW: modify interface to Flusher system
template <class T,
         class DataType,
         class NodeInfo=CCacheDataBase,
         class keyType=CFixedStringKey,
         class KeyTrait=CStringElementTraits<CFixedStringKey >,
         class Flusher=COldFlusher,
         class Culler=CExpireCuller,
         class SyncClass=CComCriticalSection,
         class StatClass=CStdStatClass >
         class CMemoryCacheBase
{
protected:
    typedef keyType keytype;
    struct NodeType : public __CACHEITEM, public NodeInfo, 
        public Flusher::CCacheData, public Culler::CCacheData
    {
		NodeType()
		{
			pos = NULL;
			dwSize = 0;
			dwRef = 0;
		}

        DataType Data;
        POSITION pos;
        DWORD dwSize;   
        DWORD dwRef;
    };

    typedef CAtlMap<keyType, NodeType *, KeyTrait> mapType;
    SyncClass m_syncObj;
    StatClass m_statObj;
    Flusher m_flusher;
    Culler m_culler;

    //memory cache configuration parameters
    DWORD m_dwMaxAllocationSize;
    DWORD m_dwMaxEntries;

    BOOL m_bInitialized;
public:

    mapType m_hashTable;
    CMemoryCacheBase() throw() :
      m_dwMaxAllocationSize(0xFFFFFFFF),
      m_dwMaxEntries(0xFFFFFFFF),
      m_bInitialized(FALSE)
    {

    }

    //Initializes the cache and the cache synchronization object
    //Also the performance monitoring
    HRESULT Initialize() throw()
    {
        if (m_bInitialized)
            return HRESULT_FROM_WIN32(ERROR_ALREADY_INITIALIZED);
        HRESULT hr;
        hr =  m_syncObj.Init();

        if (hr == S_OK)
            hr = m_statObj.Initialize();

        m_bInitialized = TRUE;

        return hr;
    }

    //removes all entries whether or not they are initialized.
    HRESULT Uninitialize() throw()
    {
        if (!m_bInitialized)
            return S_OK;

        //clear out the hash table
        m_syncObj.Lock();

        RemoveAllEntries();
        m_statObj.Uninitialize();

        m_syncObj.Unlock();
        m_syncObj.Term();

        m_bInitialized = FALSE;

        return S_OK;
    }
    
    //Adds an entry to the cache.
    //Also, adds an initial reference on the entry if phEntry is not NULL
    HRESULT AddEntry(
                    const keyType &Key,             //key for entry
                    const DataType &data,               //See the DataType template parameter
                    DWORD dwSize,                       //Size of memory to be stored in the cache 
                    HCACHEITEM *phEntry = NULL              //out pointer that will contain a handle to the new
                                                        //cache entry on success.
                    ) throw()
    {
        _ATLTRY
        {
            ATLASSERT(m_bInitialized);

            NodeType * pEntry = new NodeType;
            if (!pEntry)
                return E_OUTOFMEMORY;

			//fill entry
			if (phEntry)
			{
				*phEntry = static_cast<HCACHEITEM>(pEntry);
				pEntry->dwRef++;
			}
			pEntry->Data = data;
			pEntry->dwSize = dwSize;

				m_syncObj.Lock();

				POSITION pos = (POSITION)m_hashTable.Lookup(Key);

				if (pos != NULL)
				{
					RemoveAt(pos, FALSE);
					m_hashTable.GetValueAt(pos) = pEntry;
				}
				else
					pos = m_hashTable.SetAt(Key, pEntry);

				pEntry->pos = pos;
				m_statObj.AddElement(dwSize);
				m_flusher.Add(pEntry);
				m_culler.Add(pEntry);

				m_syncObj.Unlock();

			if (!phEntry)
				return CommitEntry(static_cast<HCACHEITEM>(pEntry));

				return S_OK;
        }
        _ATLCATCHALL()
        {
            return E_FAIL;
        }
    }

        // Commits the entry to the cache
    HRESULT CommitEntry(const HCACHEITEM hEntry)
    {
        ATLASSERT(m_bInitialized);
        if (!hEntry || hEntry == INVALID_HANDLE_VALUE)
            return E_INVALIDARG;

        m_syncObj.Lock();
        NodeType *pEntry = static_cast<NodeType *>(hEntry);
        m_culler.Commit(pEntry);
        m_syncObj.Unlock();
        return S_OK;
    }

    // Looks up an entry and returns a handle to it,
    // also updates access count and reference count
    HRESULT LookupEntry(const keyType &Key, HCACHEITEM * phEntry) throw()
    {
        ATLASSERT(m_bInitialized);
        HRESULT hr = E_FAIL;

        m_syncObj.Lock();
        POSITION pos = (POSITION)m_hashTable.Lookup(Key);
        if (pos != NULL)
        {
            NodeType * pEntry = m_hashTable.GetValueAt(pos);
            m_flusher.Access(pEntry);
            m_culler.Access(pEntry);
            if (phEntry)
            {
                pEntry->dwRef++;
                *phEntry = static_cast<HCACHEITEM>(pEntry);
            }

            m_statObj.Hit();

            hr = S_OK;
        }
        else
        {
            *phEntry = NULL;
            m_statObj.Miss();
        }
        m_syncObj.Unlock();
    
        return hr;
    }

    // Gets the data based on the handle.  Is thread-safe as long as there is a
    // reference on the data
    HRESULT GetEntryData(const HCACHEITEM hEntry, DataType *pData, DWORD *pdwSize) const throw()
    {
        ATLASSERT(m_bInitialized);
        ATLASSERT(pData != NULL || pdwSize != NULL);  // At least one should not be NULL

        if (!hEntry || hEntry == INVALID_HANDLE_VALUE)
            return E_INVALIDARG;

        NodeType * pEntry = static_cast<NodeType *>(hEntry);
        if (pData) 
            *pData = pEntry->Data;
        if (pdwSize) 
            *pdwSize = pEntry->dwSize;

        return S_OK;
    }

    // Unreferences the entry based on the handle
    DWORD ReleaseEntry(const HCACHEITEM hEntry) throw()
    {
        ATLASSERT(m_bInitialized);
        if (!hEntry || hEntry == INVALID_HANDLE_VALUE)
            return (DWORD)-1;

        m_syncObj.Lock();
        NodeType * pEntry = static_cast<NodeType *>(hEntry);
        m_flusher.Release(pEntry);
        m_culler.Release(pEntry);
        ATLASSERT(pEntry->dwRef > 0);

        DWORD dwRef = --pEntry->dwRef;
        if ((pEntry->pos == NULL) && (pEntry->dwRef == 0))
                InternalRemoveEntry(pEntry);

        m_syncObj.Unlock();

        return dwRef;
    }

    // Increments the entry's reference count
    DWORD AddRefEntry(const HCACHEITEM hEntry) throw()
    {
        ATLASSERT(m_bInitialized);
        if (!hEntry || hEntry == INVALID_HANDLE_VALUE)
            return (DWORD)-1;

        m_syncObj.Lock();
        NodeType * pEntry = static_cast<NodeType *>(hEntry);
        m_flusher.Access(pEntry);
        m_culler.Access(pEntry);
        DWORD dwRef = ++pEntry->dwRef;
        m_syncObj.Unlock();

        return dwRef;
    }

    // Removes an entry from the cache regardless of whether or 
    // not it has expired.  If there are references, it detaches
    // the entry so that future lookups will fail, and when
    // the ref count drops to zero, it will be deleted
    HRESULT RemoveEntryByKey(const keyType &Key) throw()
    {
        ATLASSERT(m_bInitialized);
        HCACHEITEM hEntry;
        HRESULT hr = LookupEntry(Key, &hEntry);
        if (hr == S_OK)
            hr = RemoveEntry(hEntry);

        return hr;
    }

    // Removes the element from the cache.  If there are still
    // references, then the entry is detached.
    HRESULT RemoveEntry(const HCACHEITEM hEntry) throw()
    {
        ATLASSERT(m_bInitialized);
        if (!hEntry || hEntry == INVALID_HANDLE_VALUE)
            return E_INVALIDARG;

        m_syncObj.Lock();
        NodeType * pEntry = static_cast<NodeType *>(hEntry);
        m_flusher.Release(pEntry);
        m_culler.Release(pEntry);
        ATLASSERT(pEntry->dwRef > 0);
        pEntry->dwRef--;
        RemoveAt(pEntry->pos, TRUE);
        m_syncObj.Unlock();

        return S_OK;
    }

    // CullEntries removes all expired items
    HRESULT CullEntries() throw()
    {
        ATLASSERT(m_bInitialized);
        m_syncObj.Lock();

        m_culler.Start();

        while (NodeType *pNode = static_cast<NodeType *>(m_culler.GetExpired()))
            RemoveAt(pNode->pos, TRUE);

        m_syncObj.Unlock();

        return S_OK;
    }

    // FlushEntries reduces the cache to meet the configuration requirements
    HRESULT FlushEntries() throw()
    {        
        ATLASSERT(m_bInitialized);
        CullEntries(); 

        m_syncObj.Lock();

        NodeType * pNode = static_cast<NodeType *>(m_flusher.GetStart());

        while (pNode &&
               (((m_statObj.GetCurrentEntryCount() > m_dwMaxEntries)) ||
                ((m_statObj.GetCurrentAllocSize() > m_dwMaxAllocationSize))))
        {
            NodeType *pNext = static_cast<NodeType *>(m_flusher.GetNext(pNode));

            if (pNode->dwRef == 0)
                RemoveAt(pNode->pos, TRUE);

            pNode = pNext;
        }
        m_syncObj.Unlock();

        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE SetMaxAllowedSize(DWORD dwSize) throw()
    {
        m_dwMaxAllocationSize = dwSize;
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllowedSize(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_dwMaxAllocationSize;
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE SetMaxAllowedEntries(DWORD dwSize) throw()
    {
        m_dwMaxEntries = dwSize;
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllowedEntries(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_dwMaxEntries;
        return S_OK;
    }


    HRESULT ResetCache() throw()
    {
        ATLASSERT(m_bInitialized);
        m_syncObj.Lock();
        ClearStats();
        m_hashTable.RemoveAll();
        m_syncObj.Unlock();
        return S_OK;
    }

    HRESULT ClearStats() throw()
    {
        m_statObj.ResetCounters();
        return S_OK;
    }

    HRESULT RemoveAllEntries() throw()
    {
        ATLASSERT(m_bInitialized);
        m_syncObj.Lock();
        m_hashTable.DisableAutoRehash();
        POSITION pos = m_hashTable.GetStartPosition();
        POSITION oldpos;
        while (pos != NULL)
        {
            oldpos = pos;
            m_hashTable.GetNext(pos);
            RemoveAt(oldpos, TRUE);
        }
        m_hashTable.EnableAutoRehash();
        m_syncObj.Unlock();

        return S_OK;
    }

protected:

    // Checks to see if the cache can accommodate any new entries within
    // its allocation and entry count limits.  
    bool CanAddEntry(DWORD dwSizeToAdd) throw()
    {
        return CheckAlloc(dwSizeToAdd) && CheckEntryCount(1);
    }

    // Checks to see if the cache can accommodate dwSizeToAdd additional
    // allocation within its allocation limit.
    bool CheckAlloc(DWORD dwSizeToAdd) throw()
    {
        if (m_dwMaxAllocationSize == 0xFFFFFFFF)
            return true; //max allocation size setting hasn't been set
        DWORD dwNew = m_statObj.GetCurrentAllocSize() + dwSizeToAdd;
        return dwNew < m_dwMaxAllocationSize;
    }


    // Checks to see if the cache can accommodate dwNumEntriesToAdd
    // additional entries within its limits.
    bool CheckEntryCount(DWORD dwNumEntriesToAdd) throw()
    {
        if (m_dwMaxEntries == 0xFFFFFFFF)
            return true; //max entry size hasn't been set
        DWORD dwNew = m_statObj.GetCurrentEntryCount() + dwNumEntriesToAdd;
        return dwNew < m_dwMaxEntries;

    }

protected:
    // Takes the element at pos in the hash table and removes it from
    // the cache.  If there are no references, then the entry is
    // deleted, otherwise it is deleted by ReleaseEntry when the
    // refcount goes to zero.
    HRESULT RemoveAt(POSITION pos, BOOL bDelete) throw()
    {
        HRESULT hr = S_OK;
        ATLASSERT(pos != NULL);
        NodeType * pEntry = m_hashTable.GetValueAt(pos);
        m_flusher.Remove(pEntry);
        m_culler.Remove(pEntry);
        if (bDelete)
            m_hashTable.RemoveAtPos(pos);

        if ((long)pEntry->dwRef == 0)
            hr = InternalRemoveEntry(pEntry);
        else
            pEntry->pos = NULL;

        return S_OK;
    }
    
    // Does the actual destruction of the node.  Deletes the
    // NodeType struct and calls the inherited class's 
    // OnDestroyEntry function, where other necessary destruction
    // can take place.  Also updates the cache statistics.
    // Inherited classes should call RemoveAt unless the element's
    // refcount is zero and it has been removed from the
    // culler and flusher lists.
    HRESULT InternalRemoveEntry(NodeType * pEntry) throw()
    {
        ATLASSERT(pEntry != NULL);

        T* pT = static_cast<T*>(this);

        ATLASSERT((long)pEntry->dwRef == 0);

        pT->OnDestroyEntry(pEntry);
        
        m_statObj.ReleaseElement(pEntry->dwSize);

        free(pEntry);

        return S_OK;
    }
}; // CMemoryCacheBase

class CCacheDataBase
{
};

struct CCacheDataEx : public CCacheDataBase
{
    HINSTANCE hInstance;
    IMemoryCacheClient * pClient;
};


template <typename DataType, 
        class StatClass=CStdStatClass,
        class FlushClass=COldFlusher,
        class keyType=CFixedStringKey,  class KeyTrait=CStringElementTraits<CFixedStringKey >,
        class SyncClass=CComCriticalSection,
		class CullClass=CExpireCuller >
class CMemoryCache:
    public CMemoryCacheBase<CMemoryCache, DataType, CCacheDataEx, 
        keyType, KeyTrait, FlushClass, CullClass, SyncClass, StatClass>
{
protected:
    CComPtr<IServiceProvider> m_spServiceProv;
    CComPtr<IDllCache> m_spDllCache;
    typedef CMemoryCacheBase<CMemoryCache, DataType, CCacheDataEx, 
        keyType, KeyTrait, FlushClass, CullClass, SyncClass, StatClass> baseClass;
public:

    HRESULT Initialize(IServiceProvider * pProvider)
    {
        baseClass::Initialize();
        m_spServiceProv = pProvider;
        if (pProvider)
            return m_spServiceProv->QueryService(__uuidof(IDllCache), __uuidof(IDllCache), (void**)&m_spDllCache);
        else
            return S_OK;
    }

    HRESULT AddEntry(
                    const keyType &Key,
                    const DataType &data,
                    DWORD dwSize,
                    FILETIME * pftExpireTime = NULL,
                    HINSTANCE hInstance = NULL,
                    IMemoryCacheClient * pClient = NULL,
                    HCACHEITEM *phEntry = NULL
                    ) throw()
    {
        _ATLTRY
        {
            HRESULT hr;
            NodeType * pEntry = NULL;
            hr = baseClass::AddEntry(Key, data, dwSize, (HCACHEITEM *)&pEntry);
            if (hr != S_OK)
                return hr;

            pEntry->hInstance = hInstance;
            pEntry->pClient = pClient;
            if (pftExpireTime)
                pEntry->cftExpireTime = *pftExpireTime;

            if (hInstance && m_spDllCache)
                m_spDllCache->AddRefModule(hInstance);

            baseClass::CommitEntry(static_cast<HCACHEITEM>(pEntry));

            if (phEntry)
                *phEntry = static_cast<HCACHEITEM>(pEntry);
            else
                baseClass::ReleaseEntry(static_cast<HCACHEITEM>(pEntry));

            return S_OK;
        }
        _ATLCATCHALL()
        {
            return E_FAIL;
        }
    }

    virtual void OnDestroyEntry(const NodeType * pEntry) throw()
    {
        ATLASSERT(pEntry);
        if (!pEntry)
            return;

        if (pEntry->pClient)
            pEntry->pClient->Free((void *)&pEntry->Data);
        if (pEntry->hInstance && m_spDllCache)
            m_spDllCache->ReleaseModule(pEntry->hInstance);
    }
}; // CMemoryCache

// CStdStatData - contains the data that CStdStatClass keeps track of
#define ATL_PERF_CACHE_OBJECT 100

struct CPerfStatObject : public CPerfObject
{
	DECLARE_PERF_OBJECT(CPerfStatObject, ATL_PERF_CACHE_OBJECT, IDS_PERFMON_CACHE, IDS_PERFMON_CACHE_HELP, -1);

	BEGIN_COUNTER_MAP(CPerfStatObject)
        DEFINE_COUNTER(m_nHitCount, IDS_PERFMON_HITCOUNT, IDS_PERFMON_HITCOUNT_HELP, PERF_COUNTER_RAWCOUNT, -1)
        DEFINE_COUNTER(m_nMissCount, IDS_PERFMON_MISSCOUNT, IDS_PERFMON_MISSCOUNT_HELP, PERF_COUNTER_RAWCOUNT, -1)
        DEFINE_COUNTER(m_nCurrentAllocations, IDS_PERFMON_CURRENTALLOCATIONS, IDS_PERFMON_CURRENTALLOCATIONS_HELP, PERF_COUNTER_RAWCOUNT, -3)
        DEFINE_COUNTER(m_nMaxAllocations, IDS_PERFMON_MAXALLOCATIONS, IDS_PERFMON_MAXALLOCATIONS_HELP, PERF_COUNTER_RAWCOUNT, -3)
        DEFINE_COUNTER(m_nCurrentEntries, IDS_PERFMON_CURRENTENTRIES, IDS_PERFMON_CURRENTENTRIES_HELP, PERF_COUNTER_RAWCOUNT, -1)
        DEFINE_COUNTER(m_nMaxEntries, IDS_PERFMON_MAXENTRIES, IDS_PERFMON_MAXENTRIES_HELP, PERF_COUNTER_RAWCOUNT, -1)
	END_COUNTER_MAP()

	DWORD m_nHitCount;
	DWORD m_nMissCount;
	DWORD m_nCurrentAllocations;
	DWORD m_nMaxAllocations;
	DWORD m_nCurrentEntries;
	DWORD m_nMaxEntries;
};

// CCachePerfMon - the interface to CPerfMon, with associated definitions
class CCachePerfMon : public CPerfMon
{
public:
	BEGIN_PERF_MAP(_T("ATL Server:Cache"))
		CHAIN_PERF_OBJECT(CPerfStatObject)
    END_PERF_MAP()
};

//
//CStdStatClass
// Description
// This class provides the implementation of a standard cache statistics accounting class
class CStdStatClass
{ 
protected:
	CPerfStatObject* m_pStats;
	CPerfStatObject m_stats;

public:

    CStdStatClass() throw()
    {
		m_pStats = &m_stats;
    }

	// This function is not thread safe by design
    HRESULT Initialize(CPerfStatObject* pStats = NULL) throw()
    {
		if (pStats)
			m_pStats = pStats;
		else
			m_pStats = &m_stats;

        ResetCounters();
        return S_OK;
    }

	// This function is not thread safe by design
    HRESULT Uninitialize() throw()
    {
		m_pStats = &m_stats;
        return S_OK;
    }

    void Hit() throw()
    {
        InterlockedIncrement(reinterpret_cast<long*>(&m_pStats->m_nHitCount));
    }

    void Miss() throw()
    { 
        InterlockedIncrement(reinterpret_cast<long*>(&m_pStats->m_nMissCount));
    }

    void AddElement(DWORD dwBytes) throw()
    {
        InterlockedIncrement(reinterpret_cast<long*>(&m_pStats->m_nCurrentEntries));
        InterlockedExchangeAdd(reinterpret_cast<long*>(&m_pStats->m_nCurrentAllocations), dwBytes);

        if (m_pStats->m_nCurrentEntries > m_pStats->m_nMaxEntries)
            InterlockedExchange(reinterpret_cast<long*>(&m_pStats->m_nMaxEntries), m_pStats->m_nCurrentEntries);

        if (m_pStats->m_nCurrentAllocations > m_pStats->m_nMaxAllocations)
            InterlockedExchange(reinterpret_cast<long*>(&m_pStats->m_nMaxAllocations), m_pStats->m_nCurrentAllocations);
    }

    void ReleaseElement(DWORD dwBytes) throw()
    {
        InterlockedDecrement(reinterpret_cast<long*>(&m_pStats->m_nCurrentEntries));
        InterlockedExchangeAdd(reinterpret_cast<long*>(&m_pStats->m_nCurrentAllocations), -((long)dwBytes));
	}

    DWORD GetHitCount() throw()
    {
        return m_pStats->m_nHitCount;
    }

    DWORD GetMissCount() throw()
    {
        return m_pStats->m_nMissCount;
    }

    DWORD GetCurrentAllocSize() throw()
    {
        return m_pStats->m_nCurrentAllocations;
    }

    DWORD GetMaxAllocSize() throw()
    {
        return m_pStats->m_nMaxAllocations;
    }

    DWORD GetCurrentEntryCount() throw()
    {
        return m_pStats->m_nCurrentEntries;
    }

    DWORD GetMaxEntryCount() throw()
    {   
        return m_pStats->m_nMaxEntries;
    }

    void ResetCounters() throw()
    {
		m_pStats->m_nHitCount = 0;
		m_pStats->m_nMissCount = 0;
		m_pStats->m_nCurrentAllocations = 0;
		m_pStats->m_nMaxAllocations = 0;
		m_pStats->m_nCurrentEntries = 0;
		m_pStats->m_nMaxEntries = 0;
    }
}; // CStdStatClass

//
// CNoStatClass
// This is a noop stat class
class CNoStatClass
{ 
public:
	HRESULT Initialize() throw(){ return S_OK; }
    HRESULT Uninitialize() throw(){ return S_OK; }
	void Hit() throw(){ }
    void Miss() throw(){ }
	void AddElement(DWORD) throw(){ }
	void ReleaseElement(DWORD) throw(){ }
	DWORD GetHitCount() throw(){ return 0; }
	DWORD GetMissCount() throw(){ return 0; }
	DWORD GetCurrentAllocSize() throw(){ return 0; }
	DWORD GetMaxAllocSize() throw(){ return 0; }
	DWORD GetCurrentEntryCount() throw(){ return 0; }
	DWORD GetMaxEntryCount() throw(){ return 0; }
	void ResetCounters() throw(){ }
}; // CNoStatClass

//
//CPerfStatClass
// Description
// This class provides the implementation of a cache statistics gathering class
// with PerfMon support
class CPerfStatClass : public CStdStatClass
{
    CPerfStatObject * m_pPerfObject;
    CCachePerfMon m_PerfMon;

public:

    HRESULT Initialize(LPWSTR szName=NULL) throw()
    {
        HRESULT hr;

        if (!szName)
            szName = L"Object 1";

        m_pPerfObject = NULL;
        ATLTRACE(atlTraceCache, 2, _T("Initializing m_PerfMon\n"));
        hr = m_PerfMon.Initialize();
        if (SUCCEEDED(hr))
        {
            CPerfLock lock(&m_PerfMon);
            if (FAILED(hr = lock.GetStatus()))
            {
                return hr;
            }

            hr = m_PerfMon.CreateInstance(ATL_PERF_CACHE_OBJECT, 0, szName, reinterpret_cast<CPerfObject**>(&m_pPerfObject));
            if (FAILED(hr))
            {
                return hr;
            }

			CStdStatClass::Initialize(m_pPerfObject);
        }
        else
            ATLASSERT(m_pPerfObject == NULL);

        return hr;
    }

    HRESULT Uninitialize() throw()
    {
		CStdStatClass::Uninitialize();

        if (m_pPerfObject != NULL) // Initialized m_pPerfObject successfully above
        {
            HRESULT hr = m_PerfMon.ReleaseInstance(m_pPerfObject);
            if (hr != S_OK)
                return hr;

            m_PerfMon.UnInitialize();
        }

        return S_OK;
    }
}; // CPerfStatClass

#ifndef ATL_BLOB_CACHE_TIMEOUT
#define ATL_BLOB_CACHE_TIMEOUT 1000
#endif

//
//CBlobCache
// Description:
// Implements a cache that stores pointers to void. Uses the generic CMemoryCacheBase class
// as the implementation.
template <class MonitorClass,
		class StatClass=CStdStatClass,
		class SyncObj=CComCriticalSection,
		class FlushClass=COldFlusher,
		class CullClass=CExpireCuller >
class CBlobCache : public CMemoryCache<void*, StatClass, FlushClass, CFixedStringKey, 
    CStringElementTraits<CFixedStringKey >, SyncObj, CullClass>,
    public IMemoryCache,
    public IMemoryCacheControl,
    public IMemoryCacheStats,
    public IWorkerThreadClient
{
    typedef CMemoryCache<void*, StatClass, FlushClass, CFixedStringKey, 
        CStringElementTraits<CFixedStringKey>, SyncObj, CullClass> cacheBase;

    MonitorClass m_Monitor;

protected:
    HANDLE m_hTimer;

public:
    CBlobCache() : m_hTimer(NULL)
    {
    }

    HRESULT Initialize(IServiceProvider *pProv) throw()
    {
        HRESULT hr = cacheBase::Initialize(pProv);
        if (FAILED(hr))
            return hr;
        hr = m_Monitor.Initialize();
        if (FAILED(hr))
            return hr;
        return m_Monitor.AddTimer(ATL_BLOB_CACHE_TIMEOUT, 
            static_cast<IWorkerThreadClient*>(this), (DWORD_PTR) this, &m_hTimer);
    }

    template <class ThreadTraits>
    HRESULT Initialize(IServiceProvider *pProv, CWorkerThread<ThreadTraits> *pWorkerThread) throw()
    {
        ATLASSERT(pWorkerThread);

        HRESULT hr = S_OK;

        if (S_OK == cacheBase::Initialize(pProv))
        {
            hr = m_Monitor.Initialize(pWorkerThread);
            if (FAILED(hr))
                return hr;
            return m_Monitor.AddTimer(ATL_BLOB_CACHE_TIMEOUT, 
                static_cast<IWorkerThreadClient*>(this), (DWORD_PTR) this, &m_hTimer);
        }
        return S_OK;
    }

    HRESULT Execute(DWORD_PTR dwParam, HANDLE /*hObject*/) throw()
    {
        CBlobCache* pCache = (CBlobCache*)dwParam;
    
        if (pCache)
            pCache->Flush();
        return S_OK;
    }

    HRESULT CloseHandle(HANDLE hObject) throw()
    {
        ATLASSERT(m_hTimer == hObject);
        m_hTimer = NULL;
        ::CloseHandle(hObject);
        return S_OK;
    }

    ~CBlobCache() throw()
    {
        if (m_hTimer)
            m_Monitor.RemoveHandle(m_hTimer);
    }

    HRESULT Uninitialize() throw()
    {
        if (m_hTimer)
        {
            m_Monitor.RemoveHandle(m_hTimer);
            m_hTimer = NULL;
        }
        m_Monitor.Shutdown();
        return cacheBase::Uninitialize();
    }
    // IUnknown methods
    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void **ppv) throw()
    {
        HRESULT hr = E_NOINTERFACE;
        if (!ppv)
            hr = E_POINTER;
        else
        {
            if (InlineIsEqualGUID(riid, __uuidof(IUnknown)) ||
                InlineIsEqualGUID(riid, __uuidof(IMemoryCache)))
            {
                *ppv = (IUnknown *) (IMemoryCache *) this;
                AddRef();
                hr = S_OK;
            }
            if (InlineIsEqualGUID(riid, __uuidof(IMemoryCacheStats)))
            {
                *ppv = (IUnknown *) (IMemoryCacheStats*)this;
                AddRef();
                hr = S_OK;
            }
            if (InlineIsEqualGUID(riid, __uuidof(IMemoryCacheControl)))
            {
                *ppv = (IUnknown *) (IMemoryCacheControl*)this;
                AddRef();
                hr = S_OK;
            }

        }
        return hr;
    }
    
    ULONG STDMETHODCALLTYPE AddRef() throw()
    {
        return 1;
    }
    
    ULONG STDMETHODCALLTYPE Release() throw()
    {
        return 1;
    }
    
    // IMemoryCache Methods
    HRESULT STDMETHODCALLTYPE Add(LPCSTR szKey, void *pvData, DWORD dwSize, 
        FILETIME *pftExpireTime, 
        HINSTANCE hInstClient,
        HCACHEITEM *phEntry,
        IMemoryCacheClient *pClient) throw()
    {
        HRESULT hr = E_FAIL;
        //if it's a multithreaded cache monitor we'll let the monitor take care of
        //cleaning up the cache so we don't overflow our configuration settings.
        //if it's not a threaded cache monitor, we need to make sure we don't
        //overflow the configuration settings by adding a new element
        if (m_Monitor.GetThreadHandle()==NULL)
        {
            if (!cacheBase::CanAddEntry(dwSize))
            {
                //flush the entries and check again to see if we can add
                cacheBase::FlushEntries();
                if (!cacheBase::CanAddEntry(dwSize))
                    return E_OUTOFMEMORY;
            }
        }
        _ATLTRY
        {
            hr = cacheBase::AddEntry(szKey, pvData, dwSize,
                pftExpireTime, hInstClient, pClient, phEntry);
            return hr;
        }
        _ATLCATCHALL()
        {
            return E_FAIL;
        }
    }
    
    HRESULT STDMETHODCALLTYPE LookupEntry(LPCSTR szKey, HCACHEITEM * phEntry) throw()
    {
        return cacheBase::LookupEntry(szKey, phEntry);
    }

    HRESULT STDMETHODCALLTYPE GetData(const HCACHEITEM hKey, void **ppvData, DWORD *pdwSize) const throw()
    {
        return cacheBase::GetEntryData(hKey, ppvData, pdwSize);
    }
    
    HRESULT STDMETHODCALLTYPE ReleaseEntry(const HCACHEITEM hKey) throw()
    {
        return cacheBase::ReleaseEntry(hKey);
    }

    HRESULT STDMETHODCALLTYPE RemoveEntry(const HCACHEITEM hKey) throw()
    {
        return cacheBase::RemoveEntry(hKey);
    }
    
    HRESULT STDMETHODCALLTYPE RemoveEntryByKey(LPCSTR szKey) throw()
    {
        return cacheBase::RemoveEntryByKey(szKey);
    }
    
    HRESULT STDMETHODCALLTYPE Flush() throw()
    {
        return cacheBase::FlushEntries();
    }


    HRESULT STDMETHODCALLTYPE SetMaxAllowedSize(DWORD dwSize) throw()
    {
        return cacheBase::SetMaxAllowedSize(dwSize);
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllowedSize(DWORD *pdwSize) throw()
    {
        return cacheBase::GetMaxAllowedSize(pdwSize);
    }

    HRESULT STDMETHODCALLTYPE SetMaxAllowedEntries(DWORD dwSize) throw()
    {
        return cacheBase::SetMaxAllowedEntries(dwSize);
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllowedEntries(DWORD *pdwSize) throw()
    {
        return cacheBase::GetMaxAllowedEntries(pdwSize);
    }

    HRESULT STDMETHODCALLTYPE ResetCache() throw()
    {
        return cacheBase::ResetCache();
    }

    // IMemoryCacheStats methods
    HRESULT STDMETHODCALLTYPE ClearStats() throw()
    {
        m_statObj.ResetCounters();
        return S_OK;
    }
    
    HRESULT STDMETHODCALLTYPE GetHitCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetHitCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMissCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMissCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllocSize(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMaxAllocSize();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetCurrentAllocSize(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetCurrentAllocSize();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMaxEntryCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMaxEntryCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetCurrentEntryCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetCurrentEntryCount();
        return S_OK;
    }

}; // CBlobCache


//
// CDllCache
// This class manages a cache to handle calls to LoadLibrary
// and FreeLibrary.  
// It keeps dlls loaded even after the last call to free library
// a worker thread then calls FreeLibrary on unused dlls
//
#ifndef ATL_DLL_CACHE_TIMEOUT
    #ifdef _DEBUG
        #define ATL_DLL_CACHE_TIMEOUT   1000        // 1 sec default for debug builds
    #else
        #define ATL_DLL_CACHE_TIMEOUT   10*60000    // 10 minute default for retail builds
    #endif
#endif

class CNoDllCachePeer
{
public:
    struct DllInfo
    {
    };

    BOOL Add(HINSTANCE /*hInst*/, DllInfo * /*pInfo*/)
    {
        return TRUE;
    }

    void Remove(HINSTANCE /*hInst*/, DllInfo * /*pInfo*/)
    {
    }
};

// CDllCache
// Implements IDllCache, an interface that is used to load and unload Dlls.
// To use it, construct an instance of a CDllCache and call Initialize.
// The Initialize call has to match with the type of monitor class you 
// templatize on. The monitor thread will call IWorkerThreadClient::Execute
// after its timeout expires. Make sure to Uninitialize the object before
// it is destroyed by calling Uninitialize
//
template <class CMonitorClass, class Peer=CNoDllCachePeer>
class CDllCache : public IDllCache, 
    public IWorkerThreadClient
{
protected:
    CComCriticalSection m_critSec;
    CSimpleArray<DLL_CACHE_ENTRY> m_Dlls;
    CSimpleArray<Peer::DllInfo> m_DllInfos;
    CMonitorClass m_Monitor;
    HANDLE m_hTimer;

	void RemoveDllEntry(DLL_CACHE_ENTRY& entry)
	{
		::FreeLibrary(entry.hInstDll);
		entry.hInstDll = NULL;
		m_Dlls.RemoveAt(m_Dlls.GetSize()-1);
	}

public:
    Peer m_Peer;

    CDllCache() :
        m_hTimer(INVALID_HANDLE_VALUE)
    {

    }

    HRESULT Initialize(DWORD dwTimeout=ATL_DLL_CACHE_TIMEOUT) throw()
    {
        HRESULT hr = m_critSec.Init();
        if (FAILED(hr))
            return hr;
        hr = m_Monitor.Initialize();
        if (FAILED(hr))
            return hr;
        return m_Monitor.AddTimer(dwTimeout, this, 0, &m_hTimer);
    }

    template <class ThreadTraits>
    HRESULT Initialize(CWorkerThread<ThreadTraits> *pWorkerThread,
            DWORD dwTimeout=ATL_DLL_CACHE_TIMEOUT) throw()
    {
        HRESULT hr = m_critSec.Init();
        if (FAILED(hr))
            return hr;
        hr = m_Monitor.Initialize(pWorkerThread);
        if (FAILED(hr))
            return hr;
        return m_Monitor.AddTimer(dwTimeout, this, 0, &m_hTimer);
    }

    HRESULT Uninitialize() throw()
    {
        HRESULT hr = S_OK;

        if (m_hTimer)
        {
            m_Monitor.RemoveHandle(m_hTimer);
            m_hTimer = NULL;
        }
        m_Monitor.Shutdown();

        // free all the libraries we've cached
        int nLen = m_Dlls.GetSize();
        for (int i=0; i<nLen; i++)
        {
            DLL_CACHE_ENTRY& entry = m_Dlls[i];
            ATLASSERT(entry.dwRefs == 0);
            BOOL bRet = ::FreeLibrary(entry.hInstDll);

            if (!bRet)
            {
                hr = AtlHresultFromLastError();
                ATLTRACE(atlTraceCache, 0, _T("Free library failed on shutdown of dll cache : hr = 0x%08x)"), hr);
            }

            nLen--;
        }
        m_Dlls.RemoveAll();
        m_critSec.Term();
        return hr;

    }

    // IUnknown methods
    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void **ppv) throw()
    {
        if (!ppv)
            return E_POINTER;
        if (InlineIsEqualGUID(riid, __uuidof(IUnknown)) ||
            InlineIsEqualGUID(riid, __uuidof(IDllCache)))
        {
            *ppv = (IUnknown *) this;
            AddRef();
            return S_OK;
        }
        return E_NOINTERFACE;
    }
    
    ULONG STDMETHODCALLTYPE AddRef() throw()
    {
        return 1;
    }
    
    ULONG STDMETHODCALLTYPE Release() throw()
    {
        return 1;
    }

    // IDllCache methods
    HINSTANCE Load(LPCSTR szDllName, void *pPeerInfo) throw(...)
    {
        m_critSec.Lock();
        int nLen = m_Dlls.GetSize();
        for (int i=0; i<nLen; i++)
        {
            DLL_CACHE_ENTRY& entry = m_Dlls[i];
            if (!_stricmp(entry.szDllName, szDllName))
            {
                entry.dwRefs++;
                m_critSec.Unlock();
                if (pPeerInfo)
                {
                    Peer::DllInfo *pl = (Peer::DllInfo*)pPeerInfo;
                    *pl = m_DllInfos[i];
                }
                return entry.hInstDll;
            }
        }
        DLL_CACHE_ENTRY entry;
        entry.hInstDll = ::LoadLibraryA(szDllName);
        if (!entry.hInstDll)
        {
            m_critSec.Unlock();
            return NULL;
        }
        strcpy(entry.szDllName, szDllName);
        entry.dwRefs = 1;
        entry.bAlive = TRUE;
        m_Dlls.Add(entry);

        Peer::DllInfo *pdllInfo = (Peer::DllInfo*)pPeerInfo;

		// m_Peer could throw an exception from user code. We
		// pass that exception from here to a higher context (we
		// won't deal with user exception here).
		if (!m_Peer.Add(entry.hInstDll, pdllInfo))
		{
			RemoveDllEntry(entry);
		}


        if ((entry.hInstDll != NULL) && (!m_DllInfos.Add(*pdllInfo)))
		{
			RemoveDllEntry(entry);
		}

        m_critSec.Unlock();
        return entry.hInstDll;
    }

    BOOL Free(HINSTANCE hInstDll) throw()
    {
        m_critSec.Lock();
        int nLen = m_Dlls.GetSize();
        for (int i=0; i<nLen; i++)
        {
            DLL_CACHE_ENTRY &entry = m_Dlls[i];
            if (entry.hInstDll == hInstDll)
            {
                ATLASSERT(entry.dwRefs > 0);
                entry.bAlive = TRUE;
                entry.dwRefs--;
                m_critSec.Unlock();
                return TRUE;
            }
        }

        m_critSec.Unlock();
        // the dll wasn't found
        // in the cache, so just
        // pass along to ::FreeLibrary
        return ::FreeLibrary(hInstDll);
    }

    BOOL AddRefModule(HINSTANCE hInstDll) throw()
    {
        m_critSec.Lock();
        int nLen = m_Dlls.GetSize();
        for (int i=0; i<nLen; i++)
        {
            DLL_CACHE_ENTRY &entry = m_Dlls[i];
            if (entry.hInstDll == hInstDll)
            {
                ATLASSERT(entry.dwRefs > 0);
                entry.dwRefs++;
                m_critSec.Unlock();
                return TRUE;
            }
        }

        m_critSec.Unlock();
        return FALSE;
    }

    BOOL ReleaseModule(HINSTANCE hInstDll) throw()
    {
        m_critSec.Lock();
        int nLen = m_Dlls.GetSize();
        for (int i=0; i<nLen; i++)
        {
            DLL_CACHE_ENTRY &entry = m_Dlls[i];
            if (entry.hInstDll == hInstDll)
            {
                ATLASSERT(entry.dwRefs > 0);
                entry.bAlive = TRUE;
                entry.dwRefs--;
                m_critSec.Unlock();
                return TRUE;
            }
        }
        m_critSec.Unlock();
        return FALSE;
    }

    HRESULT GetEntries(DWORD dwCount, DLL_CACHE_ENTRY *pEntries, DWORD *pdwCopied) throw()
    {
        if (!pdwCopied)
            return E_POINTER;

        m_critSec.Lock();
        if (dwCount==0 || pEntries==NULL)
        {
            // just return the required size
            *pdwCopied = m_Dlls.GetSize();
            m_critSec.Unlock();
            return S_OK;
        }

        if (dwCount > (DWORD) m_Dlls.GetSize())
            dwCount = m_Dlls.GetSize();
        memcpy(pEntries, m_Dlls.GetData(), dwCount*sizeof(DLL_CACHE_ENTRY));
        *pdwCopied = dwCount;
        m_critSec.Unlock();
        return S_OK;
    }

    HRESULT Flush() throw()
    {
        m_critSec.Lock();
        int nLen = m_Dlls.GetSize();
        for (int i=0; i<nLen; i++)
        {
            DLL_CACHE_ENTRY &entry = m_Dlls[i];
            if (entry.dwRefs == 0 && !entry.bAlive)
            {
				_ATLTRY
				{
					m_Peer.Remove(entry.hInstDll, &m_DllInfos[i]);
				}
				_ATLCATCHALL()
				{
					ATLTRACE(atlTraceCache, 2, _T("Exception thrown from user code in CDllCache::Flush\n"));
				}

                ::FreeLibrary(entry.hInstDll);
                m_Dlls.RemoveAt(i);
                m_DllInfos.RemoveAt(i);
                i--;
                nLen--;
            }
            entry.bAlive = FALSE;
        }

        m_critSec.Unlock();
        return S_OK;
    }

    HRESULT Execute(DWORD_PTR /*dwParam*/, HANDLE /*hObject*/) throw()
    {
        Flush();
        return S_OK;
    }

    HRESULT CloseHandle(HANDLE hObject) throw()
    {
        ATLASSERT(m_hTimer == hObject);
        m_hTimer = NULL;
        ::CloseHandle(hObject);
        return S_OK;
    }
}; // CDllCache


//
//IStencilCache
//IStencilCache is used by a stencil processor to cache pointers to CStencil
//derived objects.


// {8702269B-707D-49cc-AEF8-5FFCB3D6891B}
extern "C" __declspec(selectany) IID IID_IStencilCache = { 0x8702269b, 0x707d, 0x49cc, { 0xae, 0xf8, 0x5f, 0xfc, 0xb3, 0xd6, 0x89, 0x1b } };

__interface ATL_NO_VTABLE __declspec(uuid("8702269B-707D-49cc-AEF8-5FFCB3D6891B")) 
    IStencilCache : public IUnknown
{
    // IStencilCache methods
    STDMETHOD(CacheStencil)(LPCSTR szName, //a name for this cache entry
                                void *pStencil, //a pointer to a CStencil derived object
                                DWORD dwSize, //sizeof pStencil
                                HCACHEITEM *pHandle, //out pointer to a handle to the this cache entry
                                HINSTANCE hInst, //HINSTANCE of the module putting this entry
                                                 //in the cache.
                                IMemoryCacheClient *pClient //Interface used to free this instance
                                );
    STDMETHOD(LookupStencil)(LPCSTR szName, HCACHEITEM * phStencil);
    STDMETHOD(GetStencil)(const HCACHEITEM hStencil, void ** ppStencil) const;
    STDMETHOD(AddRefStencil)(const HCACHEITEM hStencil);
    STDMETHOD(ReleaseStencil)(const HCACHEITEM hStencil);
};

// {55DEF119-D7A7-4eb7-A876-33365E1C5E1A}
extern "C" __declspec(selectany) IID IID_IStencilCacheControl = { 0x55def119, 0xd7a7, 0x4eb7, { 0xa8, 0x76, 0x33, 0x36, 0x5e, 0x1c, 0x5e, 0x1a } };
__interface ATL_NO_VTABLE __declspec(uuid("55DEF119-D7A7-4eb7-A876-33365E1C5E1A"))
IStencilCacheControl : public IUnknown
{
    //IStencilCacheControl
    STDMETHOD(RemoveStencil)(const HCACHEITEM hStencil); // Removes the stencil if there are no references,
                                                         // otherwise detaches it
    STDMETHOD(RemoveStencilByName)(LPCSTR szStencil); //removes a stencil if there are no
                                                    //references to it
    STDMETHOD(RemoveAllStencils)(); //removes all stencils that don't have references on them
    STDMETHOD(SetDefaultLifespan)(unsigned __int64 dwdwLifespan); //sets the lifespan for all stencils
                                                             //in the cache (in 100 nanosecond units (10,000,000=1 second)).
    STDMETHOD(GetDefaultLifespan)(unsigned __int64 *pdwdwLifespan);
};

#ifndef ATL_STENCIL_CACHE_TIMEOUT
    #define ATL_STENCIL_CACHE_TIMEOUT 1000
#endif

#ifndef ATL_STENCIL_LIFESPAN
#ifdef _DEBUG                    
    #define ATL_STENCIL_LIFESPAN CFileTime::Second
#else
    #define ATL_STENCIL_LIFESPAN CFileTime::Hour
#endif
#endif

// timeout before we check if the file
// has changed in m.s.
#ifndef ATL_STENCIL_CHECK_TIMEOUT
    #define ATL_STENCIL_CHECK_TIMEOUT 1000
#endif

template <class MonitorClass,
		class StatClass=CStdStatClass,
		class SyncClass=CComCriticalSection,
		class FlushClass=COldFlusher,
		class CullClass=CLifetimeCuller >
class CStencilCache :
    public CMemoryCacheBase<CStencilCache, void *, CCacheDataEx, 
        CFixedStringKey,  CStringElementTraitsI<CFixedStringKey >, 
        FlushClass, CullClass, SyncClass, StatClass>,
    public IStencilCache,
    public IStencilCacheControl,
    public IWorkerThreadClient,
    public IMemoryCacheStats,
    public CComObjectRootEx<CComGlobalsThreadModel>
{
protected:
    typedef CMemoryCacheBase<CStencilCache, void *, CCacheDataEx, 
        CFixedStringKey,  CStringElementTraitsI<CFixedStringKey >, 
        FlushClass, CullClass, SyncClass, StatClass> cacheBase;
    unsigned __int64 m_dwdwStencilLifespan;

    MonitorClass m_Monitor;
    HANDLE m_hTimer;
    CComPtr<IDllCache> m_spDllCache;

public:

    CStencilCache() throw() :
        m_dwdwStencilLifespan(ATL_STENCIL_LIFESPAN)
    {

    }

    ~CStencilCache() throw()
    {
        if (m_hTimer)
            m_Monitor.RemoveHandle(m_hTimer);
    }

    HRESULT Execute(DWORD_PTR dwParam, HANDLE /*hObject*/) throw()
    {
        CStencilCache* pCache = (CStencilCache*)dwParam;
        if (pCache)
            pCache->FlushEntries();
        return S_OK;
    }

    HRESULT CloseHandle(HANDLE hObject) throw()
    {
        ATLASSERT(m_hTimer == hObject);
        m_hTimer = NULL;
        ::CloseHandle(hObject);
        return S_OK;
    }

    HRESULT Initialize(IServiceProvider *pProv, DWORD dwStencilCacheTimeout=ATL_STENCIL_CACHE_TIMEOUT, 
        __int64 dwdwStencilLifespan=ATL_STENCIL_LIFESPAN) throw()
    {
        m_dwdwStencilLifespan = dwdwStencilLifespan;
        HRESULT hr = cacheBase::Initialize();
        if (FAILED(hr))
            return hr;
        hr = E_FAIL;
        if (pProv)
            hr = pProv->QueryService(__uuidof(IDllCache), __uuidof(IDllCache), (void**)&m_spDllCache);
        if (FAILED(hr))
            return hr;
        hr = m_Monitor.Initialize();
        if (FAILED(hr))
            return hr;
        return m_Monitor.AddTimer(dwStencilCacheTimeout, this, (DWORD_PTR) this, &m_hTimer);
    }

    template <class ThreadTraits>
    HRESULT Initialize(IServiceProvider *pProv, CWorkerThread<ThreadTraits> *pWorkerThread, 
        DWORD dwStencilCacheTimeout=ATL_STENCIL_CACHE_TIMEOUT, __int64 dwdwStencilLifespan=ATL_STENCIL_LIFESPAN) throw()
    {
        m_dwdwStencilLifespan = dwdwStencilLifespan;
        HRESULT hr = cacheBase::Initialize();
        if (FAILED(hr))
            return hr;
        hr = E_FAIL;
        if (pProv)
            hr = pProv->QueryService(__uuidof(IDllCache), __uuidof(IDllCache), (void**)&m_spDllCache);
        if (FAILED(hr))
            return hr;
        hr = m_Monitor.Initialize(pWorkerThread);
        if (FAILED(hr))
            return hr;
        return m_Monitor.AddTimer(dwStencilCacheTimeout, this, (DWORD_PTR) this, &m_hTimer);
    }


    BEGIN_COM_MAP(CStencilCache)
        COM_INTERFACE_ENTRY(IMemoryCacheStats)
        COM_INTERFACE_ENTRY(IStencilCache)
        COM_INTERFACE_ENTRY(IStencilCacheControl)
    END_COM_MAP()
//IStencilCache methods
    STDMETHOD(CacheStencil)(LPCSTR szName, void *pStencil, DWORD dwSize, HCACHEITEM *phEntry,
                HINSTANCE hInstance, IMemoryCacheClient *pClient) throw()
    {
        NodeType * pEntry = NULL;
        m_syncObj.Lock();
		HRESULT hr;
        _ATLTRY
        {
            hr = cacheBase::AddEntry(szName, pStencil, dwSize,  (HCACHEITEM *)&pEntry);
        }
        _ATLCATCHALL()
        {
            hr = E_FAIL;
        }
        if (hr != S_OK)
        {
            m_syncObj.Unlock();
            return hr;
        }

        pEntry->hInstance = hInstance;
        pEntry->pClient = pClient;
        pEntry->nLifespan = m_dwdwStencilLifespan;
        if (hInstance && m_spDllCache)
            m_spDllCache->AddRefModule(hInstance);

        cacheBase::CommitEntry(static_cast<HCACHEITEM>(pEntry));

        if (phEntry)
            *phEntry = static_cast<HCACHEITEM>(pEntry);
        else
            cacheBase::ReleaseEntry(static_cast<HCACHEITEM>(pEntry));

        m_syncObj.Unlock();
        return hr;
    }

    STDMETHOD(LookupStencil)(LPCSTR szName, HCACHEITEM * phStencil) throw()
    {
        return cacheBase::LookupEntry(szName, phStencil);
    }

    STDMETHOD(GetStencil)(const HCACHEITEM hStencil, void ** pStencil) const throw()
    {
        return cacheBase::GetEntryData(hStencil, pStencil, NULL);
    }
    
    STDMETHOD(AddRefStencil)(const HCACHEITEM hStencil) throw()
    {
        return cacheBase::AddRefEntry(hStencil);
    }

    STDMETHOD(ReleaseStencil)(const HCACHEITEM hStencil) throw()
    {
        return cacheBase::ReleaseEntry(hStencil);
    }

    //IStencilCacheControl

    STDMETHOD(RemoveStencil)(const HCACHEITEM hStencil) throw()
    {
        return cacheBase::RemoveEntry(hStencil);
    }

    STDMETHOD(RemoveStencilByName)(LPCSTR szStencil)
    {
        return cacheBase::RemoveEntryByKey(szStencil);
    }

    STDMETHOD(RemoveAllStencils)() throw()
    {
        return cacheBase::RemoveAllEntries();
    }

    STDMETHOD(SetDefaultLifespan)(unsigned __int64 dwdwLifespan) throw()
    {
        m_dwdwStencilLifespan = dwdwLifespan;
        return S_OK;
    }

    STDMETHOD(GetDefaultLifespan)(unsigned __int64 *pdwdwLifepsan) throw()
    {
        HRESULT hr = E_POINTER;
        if (pdwdwLifepsan)
        {
            *pdwdwLifepsan = m_dwdwStencilLifespan;
            hr = S_OK;
        }
        return hr;
    }

    virtual void OnDestroyEntry(const NodeType * pEntry) throw()
    {
        ATLASSERT(pEntry);
        if (!pEntry)
            return;

        if (pEntry->pClient)
            pEntry->pClient->Free((void *)&pEntry->Data);
        if (pEntry->hInstance && m_spDllCache)
            m_spDllCache->ReleaseModule(pEntry->hInstance);
    }

    HRESULT Uninitialize() throw()
    {
        if (m_hTimer)
        {
            m_Monitor.RemoveHandle(m_hTimer);
            m_hTimer = NULL;
        }
        m_Monitor.Shutdown();
        return cacheBase::Uninitialize();
    }
    // IMemoryCacheStats methods
    HRESULT STDMETHODCALLTYPE ClearStats() throw()
    {
        m_statObj.ResetCounters();
        return S_OK;
    }
    
    HRESULT STDMETHODCALLTYPE GetHitCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetHitCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMissCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMissCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllocSize(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMaxAllocSize();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetCurrentAllocSize(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetCurrentAllocSize();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMaxEntryCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMaxEntryCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetCurrentEntryCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetCurrentEntryCount();
        return S_OK;
    }
}; // CStencilCache

// {105A8866-4059-45fe-86AE-FA0EABBFBBB4}
extern "C" __declspec(selectany) IID IID_IFileCache = { 0x105a8866, 0x4059, 0x45fe, { 0x86, 0xae, 0xfa, 0xe, 0xab, 0xbf, 0xbb, 0xb4 } };

__interface ATL_NO_VTABLE __declspec(uuid("105A8866-4059-45fe-86AE-FA0EABBFBBB4"))
    IFileCache : public IUnknown
{
    // IFileCache Methods

    STDMETHOD(AddFile)( 
        LPCSTR szFileName,
        LPCSTR szTempFileName,
        FILETIME *pftExpireTime,
		void *pPeerInfo,
        HCACHEITEM * phKey);
    STDMETHOD(LookupFile)(LPCSTR szFileName, HCACHEITEM * phKey);
    STDMETHOD(GetFile)(const HCACHEITEM hKey, LPSTR * pszFileName, void **ppPeerInfo);
    STDMETHOD(ReleaseFile)(const HCACHEITEM hKey);
    STDMETHOD(RemoveFile)(const HCACHEITEM hKey);
    STDMETHOD(RemoveFileByName)(LPCSTR szFileName);
    STDMETHOD(Flush)();
};

#ifndef ATL_FILE_CACHE_TIMEOUT
    #define ATL_FILE_CACHE_TIMEOUT 1000
#endif

class CNoFileCachePeer
{
public:
	struct PeerInfo
	{
	};

	static BOOL Add(PeerInfo* /*pDest*/, void * /*pSrc*/)
	{
		return TRUE;
	}

	static BOOL Remove(const PeerInfo* /*pFileInfo*/)
	{
		return TRUE;
	}
};

template <class Peer>
struct CCacheDataPeer : public CCacheDataBase
{
	Peer::PeerInfo PeerData; 
};

// A class to keep track of files, with maintenance -- maximum size of cache,
// maximum number of entries, expiration of entries, etc. -- inherits from
// CMemoryCacheBase
template <
        class MonitorClass,
        class StatClass=CStdStatClass,
		class FileCachePeer=CNoFileCachePeer,
        class FlushClass=COldFlusher,
        class SyncClass=CComCriticalSection,
		class CullClass=CExpireCuller >
class CFileCache:
    public CMemoryCacheBase<CFileCache, LPSTR, CCacheDataPeer<FileCachePeer>, 
            CFixedStringKey,  CStringElementTraits<CFixedStringKey >, 
            FlushClass, CullClass, SyncClass, StatClass>, 
    public IWorkerThreadClient,
    public IFileCache,
    public IMemoryCacheControl,
    public IMemoryCacheStats
{
    typedef CMemoryCacheBase<CFileCache, LPSTR, CCacheDataPeer<FileCachePeer>, 
            CFixedStringKey,  CStringElementTraits<CFixedStringKey >, 
            FlushClass, CullClass, SyncClass, StatClass> cacheBase;

    MonitorClass m_Monitor;

protected:
    HANDLE m_hTimer;

public:
    HRESULT Initialize() throw()
    {
        HRESULT hr = cacheBase::Initialize();
        if (FAILED(hr))
            return hr;
        hr = m_Monitor.Initialize();
        if (FAILED(hr))
            return hr;
        return m_Monitor.AddTimer(ATL_FILE_CACHE_TIMEOUT, 
            static_cast<IWorkerThreadClient*>(this), (DWORD_PTR) this, &m_hTimer);
    }

    template <class ThreadTraits>
    HRESULT Initialize(CWorkerThread<ThreadTraits> *pWorkerThread) throw()
    {
        ATLASSERT(pWorkerThread);

        HRESULT hr = S_OK;

        if (S_OK == cacheBase::Initialize())
        {
            hr = m_Monitor.Initialize(pWorkerThread);
            if (FAILED(hr))
                return hr;
            return m_Monitor.AddTimer(ATL_FILE_CACHE_TIMEOUT, 
                static_cast<IWorkerThreadClient*>(this), (DWORD_PTR) this, &m_hTimer);
        }
        return S_OK;
    }


    // Callback for CWorkerThread
    HRESULT Execute(DWORD_PTR dwParam, HANDLE /*hObject*/) throw()
    {
        CFileCache* pCache = (CFileCache*)dwParam;
    
        if (pCache)
            pCache->Flush();
        return S_OK;
    }

    HRESULT CloseHandle(HANDLE hObject) throw()
    {
        ATLASSERT(m_hTimer == hObject);
        m_hTimer = NULL;
        ::CloseHandle(hObject);
        return S_OK;
    }

    ~CFileCache() throw()
    {
        if (m_hTimer)
        {
            m_Monitor.RemoveHandle(m_hTimer);
            m_hTimer = NULL;
        }
    }

    HRESULT Uninitialize() throw()
    {
        if (m_hTimer)
        {
            m_Monitor.RemoveHandle(m_hTimer);
            m_hTimer = NULL;
        }
        m_Monitor.Shutdown();
        return cacheBase::Uninitialize();
    }


    // IUnknown methods
    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void **ppv) throw()
    {
        HRESULT hr = E_NOINTERFACE;
        if (!ppv)
            hr = E_POINTER;
        else
        {
            if (InlineIsEqualGUID(riid, __uuidof(IUnknown)) ||
                InlineIsEqualGUID(riid, __uuidof(IFileCache)))
            {
                *ppv = (IUnknown *) (IFileCache *) this;
                AddRef();
                hr = S_OK;
            }
            if (InlineIsEqualGUID(riid, __uuidof(IMemoryCacheStats)))
            {
                *ppv = (IMemoryCacheStats*)this;
                AddRef();
                hr = S_OK;
            }
            if (InlineIsEqualGUID(riid, __uuidof(IMemoryCacheControl)))
            {
                *ppv = (IMemoryCacheControl*)this;
                AddRef();
                hr = S_OK;
            }

        }
        return hr;
    }
    
    ULONG STDMETHODCALLTYPE AddRef() throw()
    {
        return 1;
    }
    
    ULONG STDMETHODCALLTYPE Release() throw()
    {
        return 1;
    }

    // Adds a file to the cache.  A file is created with a 
    // temporary name, and then Add is called with the temp
    // file name and the final file name, along with expiration data,
    // etc.  A search on the file name will return the name of
    // the file on disk (i.e. the temporary file)
    HRESULT STDMETHODCALLTYPE AddFile(
        LPCSTR szFileName,
        LPCSTR szTempFileName, 
        FILETIME *pftExpireTime, 
		void *pPeerInfo,
        HCACHEITEM * phKey = NULL) throw()
    {
        WIN32_FILE_ATTRIBUTE_DATA fadData;
        BOOL bRet = GetFileAttributesExA(szTempFileName, GetFileExInfoStandard, &fadData);
        if (!bRet)
            return AtlHresultFromLastError();

        __int64 ddwFileSize = (fadData.nFileSizeHigh << 32) + fadData.nFileSizeLow;

        DWORD dwRecordedFileSize = (DWORD) (ddwFileSize >> 10);
        // Round the file size up to 1K if it is < 1K
        if (dwRecordedFileSize == 0) 
            dwRecordedFileSize = 1;

        if (m_Monitor.GetThreadHandle()==NULL)
        {
            if (!cacheBase::CanAddEntry(dwRecordedFileSize))
            {
                cacheBase::FlushEntries();
                if (!cacheBase::CanAddEntry(dwRecordedFileSize))
                    return E_OUTOFMEMORY;
            }
        }

        HRESULT hr = E_FAIL;
        NodeType *pEntry = NULL;
        m_syncObj.Lock();

        // Make a private copy of the file name
        CHeapPtr<char> szTempFileCopy;
        if (szTempFileCopy.Allocate(MAX_PATH))
        {
            strcpy(szTempFileCopy, szTempFileName);

            _ATLTRY
            {
                hr = cacheBase::AddEntry(szFileName, szTempFileCopy, dwRecordedFileSize, (HCACHEITEM*)&pEntry);
				szTempFileCopy.Detach();
            }
            _ATLCATCHALL()
            {
                hr = E_FAIL;
            }
        }

        if (hr != S_OK)
        {
            m_syncObj.Unlock();
            return hr;
        }


        if (pftExpireTime)
            pEntry->cftExpireTime = *pftExpireTime;

		FileCachePeer::Add(&pEntry->PeerData, pPeerInfo);
        cacheBase::CommitEntry(static_cast<HCACHEITEM>(pEntry));
        if (phKey)
            *phKey = static_cast<HCACHEITEM>(pEntry);
        else
            cacheBase::ReleaseEntry(pEntry);

        m_syncObj.Unlock();
        return hr;
    }

    // Action to take when the entry is removed from the cache
    virtual void OnDestroyEntry(const NodeType * pEntry) throw()
    {
        ATLASSERT(pEntry);
        if (!pEntry)
            return;
		FileCachePeer::Remove(&pEntry->PeerData);
        DeleteFileA(pEntry->Data);
        free(pEntry->Data);
    }

    // Looks up a file by name.  Must be released after use
    HRESULT STDMETHODCALLTYPE LookupFile(LPCSTR szFileName, HCACHEITEM * phKey) throw()
    {
        return cacheBase::LookupEntry(szFileName, phKey);
    }

    // Gets the name of the file on disk
    HRESULT STDMETHODCALLTYPE GetFile(const HCACHEITEM hKey, LPSTR * pszFileName, void **ppPeerInfo) throw()
    {
		NodeType *pEntry = (NodeType *)hKey;
		if (ppPeerInfo)
			*ppPeerInfo = &pEntry->PeerData;
        return cacheBase::GetEntryData(hKey, pszFileName, NULL);
    }

    // Releases a file
    HRESULT STDMETHODCALLTYPE ReleaseFile(const HCACHEITEM hKey) throw()
    {
        return cacheBase::ReleaseEntry(hKey);
    }

    // Releases a file and marks it for deletion
    HRESULT STDMETHODCALLTYPE RemoveFile(const HCACHEITEM hKey) throw()
    {
        return cacheBase::RemoveEntry(hKey);
    }

    // Removes a file by name -- this calls IMemoryCacheClient->Free
    // on the file name, which by default (for CFileCache) deletes the
    // file.
    HRESULT STDMETHODCALLTYPE RemoveFileByName(LPCSTR szFileName) throw()
    {
        return cacheBase::RemoveEntryByKey(szFileName);
    }

    // Flushes the entries in the cache, eliminates expired entries,
    // or if the cache exceeds the parameters (alloc size, num entries),
    // culls items based on the sweep mode
    HRESULT STDMETHODCALLTYPE Flush() throw()
    {
        return cacheBase::FlushEntries();
    }

    // IMemoryCacheControl methods
    HRESULT STDMETHODCALLTYPE SetMaxAllowedSize(DWORD dwSize) throw()
    {
        return cacheBase::SetMaxAllowedSize(dwSize);
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllowedSize(DWORD *pdwSize) throw()
    {
        return cacheBase::GetMaxAllowedSize(pdwSize);
    }

    HRESULT STDMETHODCALLTYPE SetMaxAllowedEntries(DWORD dwSize) throw()
    {
        return cacheBase::SetMaxAllowedEntries(dwSize);
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllowedEntries(DWORD *pdwSize) throw()
    {
        return cacheBase::GetMaxAllowedEntries(pdwSize);
    }

    HRESULT STDMETHODCALLTYPE ResetCache() throw()
    {
        return cacheBase::ResetCache();
    }


    // IMemoryCacheStats methods
    HRESULT STDMETHODCALLTYPE ClearStats() throw()
    {
        m_statObj.ResetCounters();
        return S_OK;
    }
    
    HRESULT STDMETHODCALLTYPE GetHitCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetHitCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMissCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMissCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMaxAllocSize(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMaxAllocSize();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetCurrentAllocSize(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetCurrentAllocSize();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetMaxEntryCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetMaxEntryCount();
        return S_OK;
    }

    HRESULT STDMETHODCALLTYPE GetCurrentEntryCount(DWORD *pdwSize) throw()
    {
        if (!pdwSize)
            return E_POINTER;
        *pdwSize = m_statObj.GetCurrentEntryCount();
        return S_OK;
    }
}; // CFileCache

class CDataConnection; // see atldbcli.h
__interface __declspec(uuid("52E7759B-D6CC-4a03-BDF3-80A6BDCA1F94")) 
IDataSourceCache : public IUnknown
{   
    // Method: Add
    // Params:
    //   szConn: Connection string of data source to connect to
    //   ppDS: Out pointer to the newly added data source
    // Comments:
    //   Attempts to open a connection to the specified data source
    //   using a CDataSource object. Once the connection is open, the
    //   CDatasource is cached.
    STDMETHOD(Add)(LPCTSTR szID, LPCOLESTR szConn, CDataConnection *pDS);

    // Method: Remove
    // Params:
    //   szConn: Specifies the connection string of the connection to close
    // Comments:
    //   Closes the specified connection and removes it's entry from the cache
    STDMETHOD(Remove)(LPCTSTR szID);

    // Method: Lookup
    // Params:
    //   szConn: Specifies the connection string of the connection to look up
    //   ppDS: Out pointer to CDataSource object that is connected to the specified
    //        data source.
    STDMETHOD(Lookup)(LPCTSTR szID, CDataConnection *pDS);

    // Method: Uninitialize
    // Params: 
    //   None
    // Comments:
    //   Closes removes all connections from the cache.
    STDMETHOD(Uninitialize)();

};
#ifndef ATL_DS_CONN_STRING_LEN
    #define ATL_DS_CONN_STRING_LEN 512
#endif

template <>
class CElementTraits< CDataConnection > :
    public CElementTraitsBase< CDataConnection >
{
public:
    static ULONG Hash( INARGTYPE t )
    {
        return( ULONG( ULONG_PTR( &t ) ) );
    }

    static bool CompareElements( INARGTYPE element1, INARGTYPE element2 )
    {
        return( element1.m_session.m_spOpenRowset == element2.m_session.m_spOpenRowset);
    }

    static int CompareElementsOrdered( INARGTYPE /*element1*/, INARGTYPE /*element2*/ )
    {
        ATLASSERT(FALSE);
        return -1;
    }

};

typedef CFixedStringT<CString, ATL_DS_CONN_STRING_LEN> atlDataSourceKey;
typedef CAtlMap<atlDataSourceKey, CDataConnection, 
            CStringElementTraits<atlDataSourceKey>, CElementTraits<CDataConnection> > atlDataSourceCacheMap;

template <class TCritSec=CComFakeCriticalSection>
class CDataSourceCache :
    public IDataSourceCache,
    public CComObjectRootEx<CComGlobalsThreadModel>
{
public:
    BEGIN_COM_MAP(CDataSourceCache)
        COM_INTERFACE_ENTRY(IDataSourceCache)
    END_COM_MAP()

    CDataSourceCache() throw()
    {
        m_cs.Init();
    }

    virtual ~CDataSourceCache () throw()
    {
	Uninitialize();
    }

    STDMETHOD(Uninitialize)() throw()
    {
	m_cs.Lock();
	m_ConnectionMap.RemoveAll();
	m_cs.Unlock();
	return S_OK;
    }

    STDMETHOD(Add)(LPCTSTR szID, LPCOLESTR szConn, CDataConnection *pSession) throw()
    {
        HRESULT hr = E_FAIL;
        if (pSession)
            *pSession = NULL;

        if (!szID)
            return E_INVALIDARG; // must have session name

        // Do a lookup to make sure we don't add multiple entries
        // with the same name. Adding multiple entries with the same name
        // could cause some entries to get orphaned.
        m_cs.Lock();
        const atlDataSourceCacheMap::CPair *pPair = 
            m_ConnectionMap.Lookup(szID);
        if (!pPair)
        {
            // try to open connection
            CDataConnection DS;
            hr = DS.Open(szConn);       
            if (hr == S_OK)
            {
                _ATLTRY
                {
                    if (m_ConnectionMap.SetAt(szID, DS))
                    {
                        if (pSession)
                            *pSession = DS; // copy connection to output.
                        hr = S_OK;
                    }
                    else
                        hr = E_FAIL; // map add failed
                }
                _ATLCATCHALL()
                {
                    hr = E_FAIL;
                }
            }
        }
        else // lookup succeeded, entry is already in cache
        {
            // Instead of opening a new connection, just copy
            // the one we already have in the cache.
            if (pSession)
                *pSession = pPair->m_value;
            hr = S_OK;
        }
        m_cs.Unlock();
        return hr;
    }

    STDMETHOD(Remove)(LPCTSTR szID) throw()
    {
        HRESULT hr = E_INVALIDARG;
        if (!szID)
            return hr; // must have session name

        m_cs.Lock();
        hr = m_ConnectionMap.RemoveKey(szID) ? S_OK : E_FAIL;
        m_cs.Unlock();
        return hr;
    }

    STDMETHOD(Lookup)(LPCTSTR szID, CDataConnection *pSession) throw()
    {
        if (!szID||!pSession)
            return E_POINTER;
            
        m_cs.Lock();
        bool bRet = m_ConnectionMap.Lookup(szID, *pSession);
        m_cs.Unlock();
        return (bRet && (bool)*pSession)? S_OK : E_FAIL;
    }

protected:
    atlDataSourceCacheMap m_ConnectionMap;
    TCritSec m_cs;
};


// Some helpers for using the datasource cache.
//
// Function: GetDataSource
// Params:
//   pProvider: Pointer to IServiceProvider that provides the 
//              data source cache service
//   szID: The name of the connection (can be same as szDS)
//   szDS: OLEDB connection string for data source
//   ppDS: Out pointer to CDataSource. The CDataSource will be connected
//         to the OLEDB provider specified by szDS on successful return.
// RetVal:
//   Returns S_OK on success.
static HRESULT ATL_NOINLINE GetDataSource(IServiceProvider *pProvider, 
                                          LPCTSTR szID, LPCOLESTR szConn, 
                                          CDataConnection *pSession) throw()
{
    if (!pProvider || !szID || !szConn || !pSession)
        return E_POINTER;

    CComPtr<IDataSourceCache> spDSCache;
    HRESULT hr;
    hr = pProvider->QueryService(__uuidof(IDataSourceCache), __uuidof(IDataSourceCache), (void**)&spDSCache);
    if (hr == S_OK && spDSCache)
    {
        hr = spDSCache->Add(szID, szConn, pSession);
    }
    return hr;
}

//
// Function: RemoveDataSource
// Params:
//   pProvider: Pointer to IServiceProvider that provides the
//              data source cache service
//   szID: Name of the datasource connection to remove from the cache
// RetVal:
//   none
// Comments:
//   Removes the datasource entry from the datasource cache. Since entries are
//   copied to the client on calls to lookup and add, removing an entry will not
//   release the connections of existing clients.
static HRESULT ATL_NOINLINE RemoveDataSource(IServiceProvider *pProvider, LPCTSTR szID) throw()
{
    if (!pProvider || !szID)
        return E_POINTER;

    CComPtr<IDataSourceCache> spDSCache;
    HRESULT hr = pProvider->QueryService(__uuidof(IDataSourceCache), __uuidof(IDataSourceCache), (void**)&spDSCache);
    if (spDSCache)
        hr = spDSCache->Remove(szID);
	return hr;
}

} // namespace ATL

#pragma warning (pop)

#endif // __ATLCACHE_H__