937 lines
16 KiB
C
937 lines
16 KiB
C
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/*++
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cacheimp.h -
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This file contains all the template function definitions required
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to make the cache manager work.
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--*/
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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void
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Cache< Data, Key, Constructor, fAtomic >::Schedule() {
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/*++
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Routine Description :
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This function runs through all the items in the Cache
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bumping TTL's. If there are any items ready to go
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then we dump them from the Cache.
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Arguments :
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None.
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Return Value :
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Nothing
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--*/
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if( !m_fValid )
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return ;
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m_Lock.ShareLock() ;
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DWORD cExpungable = 0 ;
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BOOL fExpunge = m_ExpireList.Expire( cExpungable ) ;
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m_Lock.ShareUnlock() ;
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if( fExpunge ) {
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Expunge() ;
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}
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}
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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BOOL
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Cache<Data, Key, Constructor, fAtomic>::RemoveEntry(
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CacheState* pEntry
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) {
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/*++
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Routine Description :
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This function removes an entry from the Cache.
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We call our hash table to delete the item.
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the CacheState destructor automagically removes
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the item from our linked lists.
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CALLER MUST HOLD APPROPRIATE LOCKS!
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Arguments :
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pEntry - item to be removed from cache
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Return Value :
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TRUE if successfully removed !
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--*/
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CACHEENTRY *pCacheEntry = (CACHEENTRY*)pEntry ;
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return m_Lookup.DeleteData( pCacheEntry->GetKey(), pCacheEntry ) ;
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}
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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BOOL
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Cache<Data, Key, Constructor, fAtomic>::QueryRemoveEntry(
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CacheState* pEntry ) {
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/*++
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Routine Description :
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This function is called from CacheList object to
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determine whether we want to remove an item from the Cache.
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This function is used to implement the ExpungeSpecific
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function available to clients.
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CALLER MUST HOLD APPROPRIATE LOCKS!
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Arguments :
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pEntry - item we want to determine whether it should remain !
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Return Value :
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TRUE if successfully removed !
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--*/
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CACHEENTRY *pCacheEntry = (CACHEENTRY*) pEntry ;
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if( m_pCallbackObject ) {
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return m_pCallbackObject->fRemoveCacheItem( *pCacheEntry->m_pData ) ;
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}
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return FALSE ;
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}
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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BOOL
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Cache<Data, Key, Constructor, fAtomic>::ExpungeInternal(
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const CACHEENTRY* pProtected,
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BOOL fDoCheap,
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Key* key,
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CACHEENTRY* pData
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) {
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/*++
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Routine Description :
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This function is called when we want to force some thing
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out of the cache. The caller can provide a key
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to force a particular item out of the cache.
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CALLER MUST HOLD APPROPRIATE LOCKS!
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Arguments :
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pProtected - an Element we want to make sure is not removed !
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key - Pointer to the key identifying the item to be removed
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pData - pointer to the CACHEENTRY object containing the data
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and key we wish to remove.
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Return Value :
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TRUE something is successfully removed from the cache.
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--*/
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if( key != 0 ) {
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return m_Lookup.DeleteData( *key, pData ) ;
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}
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return m_ExpireList.Expunge( this, fDoCheap, pProtected ) ;
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}
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#ifdef DEBUG
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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long Cache<Data, Key, Constructor, fAtomic>::s_cCreated = 0 ;
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#endif
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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Cache<Data, Key, Constructor, fAtomic>::Cache( ) : m_fValid( FALSE ) {
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/*++
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Routine Description :
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This function initializes our member variables.
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Arguments :
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cMax - maximum number of elements the cache should hold
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Return Value :
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Nothing
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--*/
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#ifdef DEBUG
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InterlockedIncrement( &s_cCreated ) ;
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#endif
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AddToSchedule() ;
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}
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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Cache<Data, Key, Constructor, fAtomic>::~Cache( ) {
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/*++
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Routine Description :
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This function destroys a Cache object !
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Arguments :
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None
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Return Value :
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Nothing
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--*/
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RemoveFromSchedule() ;
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//
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// Member and Base class destruction follows !!
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//
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#ifdef DEBUG
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InterlockedDecrement( &s_cCreated ) ;
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#endif
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}
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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BOOL
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Cache<Data, Key, Constructor, fAtomic>::Init(
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DWORD (*pfnHash)( const Key& ),
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DWORD dwLifetimeSeconds,
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DWORD cMaxInstances,
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PSTOPHINT_FN pfnStopHint
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) {
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/*++
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Routine Description :
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This function initializes the cache so that it is ready
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to take entries.
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Arguments :
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pfnHash - function to be used to compute hash values on keys
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dwLifetimeSeconds - The number of seconds objects should live in the Cache
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pfnStopHint - function to be used to send stop hints during
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long spins so shutdown's don't time out.
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Return Value :
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TRUE if successfull
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--*/
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m_ExpireList.m_cMax = long(cMaxInstances) ;
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m_ExpireList.m_pfnStopHint = pfnStopHint;
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m_TTL = 1 + (dwLifetimeSeconds / CScheduleThread::dwNotificationSeconds) ;
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return m_fValid = m_Lookup.Init( 100, 100, pfnHash ) ;
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}
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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BOOL
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Cache<Data, Key, Constructor, fAtomic>::Expunge(
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Key* key,
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CACHEENTRY* pData
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) {
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/*++
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Routine Description :
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This function is called when we want to force some thing
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out of the cache. The caller can provide a key
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to force a particular item out of the cache.
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WE WILL GRAB THE NECESSARY LOCKS !
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Arguments :
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pfnHash - function to be used to compute hash values on keys
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Return Value :
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TRUE if successfull
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--*/
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_ASSERT( m_fValid ) ;
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m_Lock.ExclusiveLock() ;
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BOOL fReturn = ExpungeInternal( 0, FALSE, key, pData ) ;
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m_Lock.ExclusiveUnlock() ;
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return fReturn ;
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}
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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BOOL
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Cache<Data, Key, Constructor, fAtomic>::ExpungeSpecific(
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CALLBACKOBJ* pCallbackObject,
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BOOL fForced
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) {
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/*++
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Routine Description :
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This function is called when we want to force some thing
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out of the cache. The caller can provide a key
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to force a particular item out of the cache.
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WE WILL GRAB THE NECESSARY LOCKS !
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Arguments :
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pfn - callback function used to determine what to remove
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from the Cache.
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fForced - if TRUE then we will remove from the Cache no matter
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what, even if other threads are using the object !
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Return Value :
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TRUE if successfull
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--*/
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m_Lock.ExclusiveLock() ;
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m_pCallbackObject = pCallbackObject ;
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BOOL fReturn = m_ExpireList.ExpungeSpecific( this, fForced ) ;
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m_Lock.ExclusiveUnlock() ;
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return fReturn ;
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}
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template < class Data,
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class Key,
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class Constructor,
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BOOL fAtomic
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>
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BOOL
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Cache<Data, Key, Constructor, fAtomic>::FindOrCreateInternal(
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DWORD dwHash,
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Key& key,
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Constructor& constructor,
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CRefPtr< Data >& pDataOut
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) {
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/*++
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Routine Description :
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This function is called when we want something out
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of the Cache. We will either find the object or create it.
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WE WILL GRAB THE NECESSARY LOCKS !
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Arguments :
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key - The unique key used to find the item in the Cache.
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constructor - An object to pass to the Data's constructor and Init
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functions.
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pDataOut - Smart pointer which receives the result
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Return Value :
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TRUE if successfull
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--*/
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BOOL fReturn = FALSE ;
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pDataOut = 0 ;
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if( !m_fValid ) {
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SetLastError( 0 ) ;
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return FALSE ;
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} else {
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m_Lock.ShareLock() ;
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//
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// See if we can find an Entry in the cache for the item we want.
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//
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CACHEENTRY *pEntry = m_Lookup.SearchKeyHash( dwHash, key ) ;
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if( pEntry ) {
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pDataOut = pEntry->m_pData ;
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fReturn = TRUE ;
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m_ExpireList.LiveLonger( pEntry, (m_TTL/2)+1 ) ;
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}
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m_Lock.ShareUnlock() ;
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if( pDataOut == 0 ) {
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m_Lock.ExclusiveLock() ;
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//
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// Check that the Item we want in the Cache didn't make it
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// into the Cache in the brief moment we switched from a shared
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// to an exclusive lock.
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//
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pEntry = m_Lookup.SearchKeyHash( dwHash, key ) ;
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if( pEntry != 0 ) {
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//
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// It's in the cache - return the cached object !
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//
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pDataOut = pEntry->m_pData ;
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fReturn = TRUE ;
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m_ExpireList.LiveLonger( pEntry, (m_TTL/2)+1 ) ;
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m_Lock.ExclusiveUnlock() ;
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} else {
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//
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// We're going to have to create one of the elements that goes
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// in the cache. Let's do that now !
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//
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const CACHEENTRY *pCacheEntry = 0 ;
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BOOL fOverFlow = FALSE ;
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Data *pData = 0 ;
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//
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// We Add another brace here because we want to explicitly manage
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// the lifetime of tempCacheEntry
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//
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{
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//
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// tempCacheEntry will be copied by the FHash template into
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// another CACHEENTRY object when it does its insertion.
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//
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CACHEENTRY tempCacheEntry( m_TTL ) ;
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//
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// The constructor of the Data object is expected to initialize
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// only the 'key' data of the Data object so that the data can be
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// found in the Cache.
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//
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tempCacheEntry.m_pData = pData = new Data( key, constructor ) ;
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if( tempCacheEntry.m_pData ) {
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pCacheEntry = m_Lookup.InsertDataHash( dwHash, tempCacheEntry ) ;
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if( pCacheEntry ) {
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if( m_ExpireList.Append( pCacheEntry ) ) {
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if( !ExpungeInternal( pCacheEntry, TRUE ) ) {
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m_ExpireList.ForceExpunge( this, pCacheEntry ) ;
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}
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}
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pDataOut = pCacheEntry->m_pData ;
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pDataOut->ExclusiveLock() ;
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} else {
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//
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// The Insertion failed !
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// Falling through correctly handles this error case !
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//
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}
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}
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//
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// Delete tempCacheEntry's reference to the Data object.
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// if an error occurred inserting into hash tables etc...
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// this will automatically destroy the data object.
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//
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tempCacheEntry.m_pData = 0 ;
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}
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//
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// Release the cache's lock. We do this now - the constructor
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// for the 'Data' object should do minimal work. We will not call
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// the init function for the Data object, with the 'cache' locks
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// relingquished. This lets others use the cache while expensive
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// construction operations continue.
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//
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m_Lock.ExclusiveUnlock() ;
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//
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// Complete the initialization of the new Data item if it exists !
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//
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if( pDataOut != 0 ) {
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BOOL fSuccess = pDataOut->Init( constructor ) ;
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pDataOut->ExclusiveUnlock() ;
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if( fSuccess ) {
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fReturn = TRUE ;
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} else {
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pDataOut = 0 ;
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//
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// Need to Expire the entry we just placed in the Cache !
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//
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// NOTE : Expunge() manages its own locks !!!
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//
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Expunge( &key ) ;
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|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
return fReturn ;
|
||
|
}
|
||
|
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
inline BOOL
|
||
|
Cache<Data, Key, Constructor, fAtomic>::FindOrCreate(
|
||
|
Key& key,
|
||
|
Constructor& constructor,
|
||
|
CRefPtr< Data >& pDataOut ) {
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
This function is called when we want something out
|
||
|
of the Cache. We will either find the object or create it.
|
||
|
|
||
|
WE WILL GRAB THE NECESSARY LOCKS !
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
key - The unique key used to find the item in the Cache.
|
||
|
constructor - An object to pass to the Data's constructor and Init
|
||
|
functions.
|
||
|
pDataOut - Smart pointer which receives the result
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
TRUE if successfull
|
||
|
|
||
|
--*/
|
||
|
|
||
|
|
||
|
DWORD dw = m_pfnHash( key ) ;
|
||
|
|
||
|
return FindOrCreateInternal( dw,
|
||
|
key,
|
||
|
constructor,
|
||
|
pDataOut
|
||
|
) ;
|
||
|
}
|
||
|
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
MultiCache< Data, Key, Constructor, fAtomic >::MultiCache() :
|
||
|
m_fValid( FALSE ),
|
||
|
m_pCaches( 0 ) ,
|
||
|
m_cSubCaches( 0 ),
|
||
|
m_pfnHash( 0 ) {
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
This function initializes the MultiCache's data structures
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
None.
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
Nothing
|
||
|
|
||
|
--*/
|
||
|
}
|
||
|
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
MultiCache< Data, Key, Constructor, fAtomic >::~MultiCache() {
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
This function destroys all of our data structures - release
|
||
|
all of our subcaches !
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
None.
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
Nothing
|
||
|
|
||
|
--*/
|
||
|
|
||
|
|
||
|
if( m_pCaches ) {
|
||
|
|
||
|
delete[] m_pCaches ;
|
||
|
|
||
|
}
|
||
|
|
||
|
}
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
BOOL
|
||
|
MultiCache< Data, Key, Constructor, fAtomic >::Init(
|
||
|
DWORD (*pfnHash)( const Key & ),
|
||
|
DWORD dwLifetimeSeconds,
|
||
|
DWORD cSubCaches,
|
||
|
DWORD cMaxElements,
|
||
|
PSTOPHINT_FN pfnStopHint) {
|
||
|
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
This function initializes the MultiCache - we use
|
||
|
multiple independent Caches to split the work
|
||
|
of caching all the data.
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
None.
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
Nothing
|
||
|
|
||
|
--*/
|
||
|
|
||
|
|
||
|
//
|
||
|
// Check that we're in the right state for this !
|
||
|
//
|
||
|
_ASSERT( !m_fValid ) ;
|
||
|
_ASSERT( m_pCaches == 0 ) ;
|
||
|
|
||
|
//
|
||
|
// Validate our arguments !!!
|
||
|
//
|
||
|
_ASSERT( pfnHash != 0 ) ;
|
||
|
_ASSERT( dwLifetimeSeconds != 0 ) ;
|
||
|
_ASSERT( cSubCaches != 0 ) ;
|
||
|
_ASSERT( cMaxElements != 0 ) ;
|
||
|
|
||
|
m_pfnHash = pfnHash ;
|
||
|
m_cSubCaches = cSubCaches ;
|
||
|
|
||
|
//
|
||
|
// Allocate the necessary subcaches !
|
||
|
//
|
||
|
|
||
|
m_pCaches = new CACHEINSTANCE[m_cSubCaches] ;
|
||
|
|
||
|
if( !m_pCaches ) {
|
||
|
return FALSE ;
|
||
|
} else {
|
||
|
|
||
|
for( DWORD i=0; i<cSubCaches; i++ ) {
|
||
|
|
||
|
if( !m_pCaches[i].Init( m_pfnHash, dwLifetimeSeconds, (cMaxElements / cSubCaches) + 1, pfnStopHint ) ) {
|
||
|
delete m_pCaches ;
|
||
|
return FALSE ;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
m_fValid = TRUE ;
|
||
|
return TRUE ;
|
||
|
}
|
||
|
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
DWORD
|
||
|
MultiCache< Data, Key, Constructor, fAtomic >::ChooseInstance(
|
||
|
DWORD dwHash
|
||
|
) {
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
Given a Key figure out which of our subinstances we wish to use.
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
None.
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
Nothing
|
||
|
|
||
|
--*/
|
||
|
|
||
|
|
||
|
//
|
||
|
// Check that we're in the right state for this !
|
||
|
//
|
||
|
_ASSERT( m_fValid ) ;
|
||
|
_ASSERT( m_pCaches != 0 ) ;
|
||
|
|
||
|
//
|
||
|
// Validate our arguments !!!
|
||
|
//
|
||
|
_ASSERT( m_pfnHash != 0 ) ;
|
||
|
_ASSERT( m_cSubCaches != 0 ) ;
|
||
|
|
||
|
|
||
|
//DWORD dwHash = m_pfnHash( k ) ;
|
||
|
|
||
|
//
|
||
|
// Constants below stolen from C-runtime rand() function !
|
||
|
//
|
||
|
|
||
|
dwHash = (((dwHash * 214013) +2531011) >> 8) % m_cSubCaches ;
|
||
|
|
||
|
return dwHash ;
|
||
|
|
||
|
}
|
||
|
|
||
|
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
BOOL
|
||
|
MultiCache< Data, Key, Constructor, fAtomic >::Expunge(
|
||
|
Key* pk,
|
||
|
CACHEENTRY* pData
|
||
|
) {
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
Either force a specified element out of the cache,
|
||
|
or force out all those that are ready to go !
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
None.
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
Nothing
|
||
|
|
||
|
--*/
|
||
|
|
||
|
if( pk != 0 ) {
|
||
|
|
||
|
DWORD dw = m_pfnHash( *pk ) ;
|
||
|
|
||
|
CACHEINSTANCE* pInstance = &m_pCacges[ChooseInstance( dw )] ;
|
||
|
return pInstance->Expunge( pk, pData ) ;
|
||
|
|
||
|
} else {
|
||
|
|
||
|
BOOL fReturn = TRUE ;
|
||
|
for( DWORD i=0; i<m_cSubCaches; i++ ) {
|
||
|
|
||
|
fReturn &= m_pCaches[i].Expunge() ;
|
||
|
|
||
|
}
|
||
|
}
|
||
|
return fReturn ;
|
||
|
}
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
BOOL
|
||
|
MultiCache< Data, Key, Constructor, fAtomic >::ExpungeSpecific(
|
||
|
CALLBACKOBJ* pCallbackObject,
|
||
|
BOOL fForced
|
||
|
) {
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
Either force a specified element out of the cache,
|
||
|
or force out all those that are ready to go !
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
None.
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
Nothing
|
||
|
|
||
|
--*/
|
||
|
|
||
|
BOOL fReturn = TRUE ;
|
||
|
for( DWORD i=0; i<m_cSubCaches; i++ ) {
|
||
|
|
||
|
fReturn &= m_pCaches[i].ExpungeSpecific( pCallbackObject, fForced ) ;
|
||
|
|
||
|
}
|
||
|
return fReturn ;
|
||
|
}
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
BOOL
|
||
|
MultiCache< Data, Key, Constructor, fAtomic >::FindOrCreate(
|
||
|
Key& key,
|
||
|
Constructor& constructor,
|
||
|
CRefPtr< Data >& pDataOut
|
||
|
) {
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
None.
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
Nothing
|
||
|
|
||
|
--*/
|
||
|
|
||
|
DWORD dw = m_pfnHash( key ) ;
|
||
|
|
||
|
CACHEINSTANCE* pInstance = &m_pCaches[ChooseInstance(dw)] ;
|
||
|
|
||
|
return pInstance->FindOrCreateInternal( dw, key, constructor, pDataOut ) ;
|
||
|
|
||
|
}
|
||
|
|
||
|
|
||
|
template < class Data,
|
||
|
class Key,
|
||
|
class Constructor,
|
||
|
BOOL fAtomic
|
||
|
>
|
||
|
BOOL
|
||
|
MultiCache< Data, Key, Constructor, fAtomic >::FindOrCreate(
|
||
|
Key& key,
|
||
|
DWORD dw,
|
||
|
Constructor& constructor,
|
||
|
CRefPtr< Data >& pDataOut
|
||
|
) {
|
||
|
/*++
|
||
|
|
||
|
Routine Description :
|
||
|
|
||
|
|
||
|
Arguments :
|
||
|
|
||
|
None.
|
||
|
|
||
|
Return Value :
|
||
|
|
||
|
Nothing
|
||
|
|
||
|
--*/
|
||
|
|
||
|
_ASSERT( dw == m_pfnHash( key ) ) ;
|
||
|
|
||
|
CACHEINSTANCE* pInstance = &m_pCaches[ChooseInstance(dw)] ;
|
||
|
|
||
|
return pInstance->FindOrCreateInternal( dw, key, constructor, pDataOut ) ;
|
||
|
|
||
|
}
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|
||
|
|