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/*
* Copyright (C) 2007-2013 Xagasoft, All rights reserved.
*
* This file is part of the libbu++ library and is released under the
* terms of the license contained in the file LICENSE.
*/
#ifndef BU_MYRIAD_CACHE_H
#define BU_MYRIAD_CACHE_H
#include "bu/cachebase.h"
#include "bu/myriad.h"
#include "bu/myriadstream.h"
#include "bu/file.h"
#include "bu/streamstack.h"
namespace Bu
{
template<typename keytype, typename obtype>
class MyriadCache : public Bu::CacheBase<keytype, obtype>
{
public:
MyriadCache( Bu::Stream &sStore, int iBlockSize=512, int iPreallocate=8 ) :
sStore( sStore ),
mStore( sStore, iBlockSize, iPreallocate ),
bStructureChanged( false )
{
try
{
Bu::ReadWriteMutex::ReadLocker l( rwStore );
Bu::MyriadStream ms = mStore.openStream( 1 );
Bu::Archive ar( ms, Bu::Archive::load );
uint8_t uVer;
ar >> uVer;
switch( uVer )
{
case 0:
ar >> hIndex;
break;
}
}
catch(...)
{
if( mStore.createStreamWithId( 1 ) != 1 )
throw Bu::ExceptionBase("Error creating index stream.");
_sync();
}
}
virtual ~MyriadCache()
{
_sync();
}
using typename Bu::CacheBase<keytype,obtype>::KeyList;
virtual typename Bu::CacheBase<keytype,obtype>::KeyList getKeys() const
{
Bu::ReadWriteMutex::ReadLocker rl( rwStore );
return hIndex.getKeys();
}
virtual int getSize() const
{
Bu::ReadWriteMutex::ReadLocker rl( rwStore );
return hIndex.getSize();
}
protected:
virtual bool _has( const keytype &key )
{
Bu::ReadWriteMutex::ReadLocker rl( rwStore );
return hIndex.has( key );
}
virtual void _create( const obtype *o )
{
Bu::ReadWriteMutex::WriteLocker wl( rwStore );
hIndex.insert( o->getKey(), mStore.createStream() );
_save( o );
bStructureChanged = true;
}
virtual void _erase( const keytype &k )
{
Bu::ReadWriteMutex::WriteLocker wl( rwStore );
mStore.deleteStream( hIndex.get( k ) );
hIndex.erase( k );
bStructureChanged = true;
}
virtual obtype *_load( const keytype &k )
{
Bu::MyriadStream ms = mStore.openStream( hIndex.get( k ) );
return _cacheObjectLoad<obtype>( ms );
}
virtual void _save( const obtype *o )
{
Bu::MyriadStream ms = mStore.openStream( hIndex.get( o->getKey() ) );
_cacheObjectSave( ms, o );
ms.setSize( ms.tell() );
}
virtual void _sync()
{
Bu::ReadWriteMutex::ReadLocker wl( rwStore );
if( !bStructureChanged )
return;
Bu::MyriadStream ms = mStore.openStream( 1 );
Bu::Archive ar( ms, Bu::Archive::save );
ar << (uint8_t)0 << hIndex;
ar.close();
ms.setSize( ms.tell() );
bStructureChanged = false;
}
private:
Bu::Stream &sStore;
Bu::Myriad mStore;
Bu::Hash<keytype, int> hIndex;
mutable Bu::ReadWriteMutex rwStore;
bool bStructureChanged;
};
}
#endif
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