/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/*
* $Id: ScopeEvaluator.java 307079 2005-10-07 10:38:21Z trustin $
*
* -- (c) LDAPd Group --
* -- Please refer to the LICENSE.txt file in the root directory of --
* -- any LDAPd project for copyright and distribution information. --
*
* Created on Oct 9, 2003
*/
package org.apache.ldap.server.partition.impl.btree;
import java.math.BigInteger;
import javax.naming.NamingException;
import javax.naming.directory.SearchControls;
import org.apache.ldap.common.filter.ExprNode;
import org.apache.ldap.common.filter.ScopeNode;
import org.apache.ldap.common.message.DerefAliasesEnum;
/**
* Evaluates ScopeNode assertions on candidates using a database.
*
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
* @version $Rev: 307079 $
*/
public class ScopeEvaluator implements Evaluator
{
/** Database used to evaluate scope with */
private BTreeDirectoryPartition db;
/**
* Creates a scope node evaluator for search expressions.
*
* @param db the database used to evaluate scope node
*/
public ScopeEvaluator( BTreeDirectoryPartition db )
{
this.db = db;
}
/**
* @see org.apache.ldap.server.partition.impl.btree.Evaluator#evaluate(ExprNode, org.apache.ldap.server.partition.impl.btree.IndexRecord)
*/
public boolean evaluate( ExprNode node, IndexRecord record )
throws NamingException
{
ScopeNode snode = ( ScopeNode ) node;
switch( snode.getScope() )
{
case( SearchControls.OBJECT_SCOPE ):
String dn = db.getEntryDn( record.getEntryId() );
return dn.equals( snode.getBaseDn() );
case( SearchControls.ONELEVEL_SCOPE ):
return assertOneLevelScope( snode, record.getEntryId() );
case( SearchControls.SUBTREE_SCOPE ):
return assertSubtreeScope( snode, record.getEntryId() );
default:
throw new NamingException( "Unrecognized search scope!" );
}
}
/**
* Asserts whether or not a candidate has one level scope while taking
* alias dereferencing into account.
*
* @param node the scope node containing the base and alias handling mode
* @param id the candidate to assert which can be any db entry's id
* @return true if the candidate is within one level scope whether or not
* alias dereferencing is enabled.
* @throws NamingException if the index lookups fail.
*/
public boolean assertSubtreeScope( final ScopeNode node,
final BigInteger id ) throws NamingException
{
String dn = db.getEntryDn( id );
DerefAliasesEnum mode = node.getDerefAliases();
Object baseId = db.getEntryId( node.getBaseDn() );
boolean isDescendant = dn.endsWith( node.getBaseDn() );
/*
* The candidate id could be any entry in the db. If search
* dereferencing is not enabled then we return the results of the
* descendant test.
*/
if ( ! mode.derefInSearching() )
{
return isDescendant;
}
/*
* From here down alias dereferencing is enabled. We determine if the
* candidate id is an alias, if so we reject it since aliases should
* not be returned.
*/
Index idx = db.getAliasIndex();
if ( null != idx.reverseLookup( id ) )
{
return false;
}
/*
* The candidate is NOT an alias at this point. So if it is a
* descendant we just return it since it is in normal subtree scope.
*/
if ( isDescendant )
{
return true;
}
/*
* At this point the candidate is not a descendant and it is not an
* alias. We need to check if the candidate is in extended subtree
* scope by performing a lookup on the subtree alias index. This index
* stores a tuple mapping the baseId to the ids of objects brought
* into subtree scope of the base by an alias:
*
* ( baseId, aliasedObjId )
*
* If the candidate id is an object brought into subtree scope then
* the lookup returns true accepting the candidate. Otherwise the
* candidate is rejected with a false return because it is not in scope.
*/
idx = db.getSubAliasIndex();
return idx.hasValue( baseId, id );
}
/**
* Asserts whether or not a candidate has one level scope while taking
* alias dereferencing into account.
*
* @param node the scope node containing the base and alias handling mode
* @param id the candidate to assert which can be any db entry's id
* @return true if the candidate is within one level scope whether or not
* alias dereferencing is enabled.
* @throws NamingException if the index lookups fail.
*/
public boolean assertOneLevelScope( final ScopeNode node,
final BigInteger id ) throws NamingException
{
DerefAliasesEnum mode = node.getDerefAliases();
Object baseId = db.getEntryId( node.getBaseDn() );
Index idx = db.getHierarchyIndex();
boolean isChild = idx.hasValue( baseId, id );
/*
* The candidate id could be any entry in the db. If search
* dereferencing is not enabled then we return the results of the child
* test.
*/
if ( ! mode.derefInSearching() )
{
return isChild;
}
/*
* From here down alias dereferencing is enabled. We determine if the
* candidate id is an alias, if so we reject it since aliases should
* not be returned.
*/
idx = db.getAliasIndex();
if ( null != idx.reverseLookup( id ) )
{
return false;
}
/*
* The candidate is NOT an alias at this point. So if it is a child we
* just return it since it is in normal one level scope.
*/
if ( isChild )
{
return true;
}
/*
* At this point the candidate is not a child and it is not an alias.
* We need to check if the candidate is in extended one level scope by
* performing a lookup on the one level alias index. This index stores
* a tuple mapping the baseId to the id of objects brought into the
* one level scope of the base by an alias: ( baseId, aliasedObjId )
* If the candidate id is an object brought into one level scope then
* the lookup returns true accepting the candidate. Otherwise the
* candidate is rejected with a false return because it is not in scope.
*/
idx = db.getOneAliasIndex();
return idx.hasValue( baseId, id );
}
}