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//
// VolatileCache.cc
//
// VolatileCache: the simplest non-persistent Query result cache.
// This is default policy.
//
// Part of the ht://Dig package <http://www.htdig.org/>
// Copyright (c) 1995-2004 The ht://Dig Group
// For copyright details, see the file COPYING in your distribution
// or the GNU Library General Public License (LGPL) version 2 or later
// <http://www.gnu.org/copyleft/lgpl.html>
//
// $Id: VolatileCache.cc,v 1.4 2004/05/28 13:15:24 lha Exp $
//
#include "VolatileCache.h"
#include "ResultList.h"
//
// a pseudo-constant empty result list
// used to avoid null pointers in the cache
//
ResultList theEmptyResult;
ResultList * const
VolatileCache::empty = &theEmptyResult;
extern int debug;
//
// find a cache entry
//
ResultList *
VolatileCache::Lookup(const String &signature)
{
ResultList *result = (ResultList *)cache[signature];
return result;
}
//
// add a cache entry
//
void
VolatileCache::Add(const String &signature, ResultList *entry)
{
ResultList *previous = (ResultList *)cache[signature];
if(previous && previous != empty)
{
delete previous;
}
if(!entry)
{
entry = empty;
}
cache.Add(signature, entry);
}
//
// clear the in-memory cache
// avoids deletion of the shared 'empty' element
//
VolatileCache::~VolatileCache()
{
if(debug) cerr << "query CLEAR: entries=" << cache.Count() << endl;
cache.Start_Get();
ResultList *kill = (ResultList *)cache.Get_NextElement();
while(kill)
{
if(kill != empty)
{
delete kill;
}
kill = (ResultList *)cache.Get_NextElement();
}
cache.Release();
}
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