QuotaCacheAccessor.cpp

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/*
// $Id: //open/dev/fennel/cache/QuotaCacheAccessor.cpp#12 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
// Portions Copyright (C) 1999-2009 John V. Sichi
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "fennel/common/CommonPreamble.h"
#include "fennel/cache/QuotaCacheAccessor.h"

FENNEL_BEGIN_CPPFILE("$Id: //open/dev/fennel/cache/QuotaCacheAccessor.cpp#12 $");

QuotaCacheAccessor::QuotaCacheAccessor(
    SharedQuotaCacheAccessor pSuperQuotaAccessorInit,
    SharedCacheAccessor pDelegateInit,
    uint maxLockedPagesInit)
    : TransactionalCacheAccessor(pDelegateInit),
      pSuperQuotaAccessor(pSuperQuotaAccessorInit),
      maxLockedPages(maxLockedPagesInit)
{
}

QuotaCacheAccessor::~QuotaCacheAccessor()
{
    assert(!nPagesLocked);
}

CachePage *QuotaCacheAccessor::lockPage(
    BlockId blockId,
    LockMode lockMode,
    bool readIfUnmapped,
    MappedPageListener *pMappedPageListener,
    TxnId txnId)
{
    CachePage *pPage = TransactionalCacheAccessor::lockPage(
        blockId,lockMode,readIfUnmapped,pMappedPageListener,txnId);
    if (pPage) {
        incrementUsage();
    }
    return pPage;
}

void QuotaCacheAccessor::unlockPage(
    CachePage &page,
    LockMode lockMode,
    TxnId txnId)
{
    decrementUsage();
    TransactionalCacheAccessor::unlockPage(page,lockMode,txnId);
}

void QuotaCacheAccessor::incrementUsage()
{
    assert(nPagesLocked < maxLockedPages);
    ++nPagesLocked;
    if (pSuperQuotaAccessor) {
        pSuperQuotaAccessor->incrementUsage();
    }
}

void QuotaCacheAccessor::decrementUsage()
{
    assert(nPagesLocked);
    --nPagesLocked;
    if (pSuperQuotaAccessor) {
        pSuperQuotaAccessor->decrementUsage();
    }
}

uint QuotaCacheAccessor::getMaxLockedPages()
{
    return maxLockedPages;
}

void QuotaCacheAccessor::setMaxLockedPages(uint nPages)
{
    assert(nPages >= nPagesLocked);
    maxLockedPages = nPages;
}

FENNEL_END_CPPFILE("$Id: //open/dev/fennel/cache/QuotaCacheAccessor.cpp#12 $");

// End QuotaCacheAccessor.cpp

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