/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.apache.jena.tdb.transaction;
import java.nio.ByteBuffer ;
import java.util.Iterator ;
import org.apache.jena.atlas.iterator.Iter ;
import org.apache.jena.atlas.lib.Pair ;
import org.apache.jena.atlas.lib.StrUtils ;
import org.apache.jena.atlas.logging.Log ;
import org.apache.jena.tdb.base.block.Block ;
import org.apache.jena.tdb.base.file.FileException ;
import org.apache.jena.tdb.base.objectfile.ObjectFile ;
public class ObjectFileTrans implements ObjectFile, TransactionLifecycle
{
private final ObjectFile transObjects ;
private long otherAllocOffset ; // record where we start allocating
private boolean passthrough = false ;
private boolean inTransaction = false ;
private final ObjectFile base ;
// For recovery replay, we need to truncate "base" first.
public ObjectFileTrans(Transaction txn, ObjectFile base, ObjectFile other)
{
// The "other" object file must use the same allocation policy.
this.base = base ;
this.transObjects = other ;
inTransaction = false ;
// [TxTDB:PATCH-UP] Begin is not being called.
this.otherAllocOffset = base.length() ;
//Log.info(this, getLabel()+": otherAllocOffset = "+otherAllocOffset) ;
}
// Begin read ==> passthrough.
@Override
public void begin(Transaction txn)
{
passthrough = false ;
inTransaction = true ;
transObjects.reposition(0) ;
this.otherAllocOffset = base.length() ;
}
@Override
public void commitPrepare(Transaction txn)
{
if ( ! inTransaction )
throw new TDBTransactionException("Not in a transaction for a commit to happen") ;
transObjects.sync() ;
}
@Override
public void commitEnact(Transaction txn)
{
if ( ! inTransaction )
throw new TDBTransactionException("Not in a transaction for a commit to happen") ;
append() ;
base.sync() ;
transObjects.reposition(0) ;
}
@Override
public void abort(Transaction txn)
{
transObjects.reposition(0) ;
}
@Override
public void commitClearup(Transaction txn)
{
transObjects.truncate(0) ;
passthrough = true ;
}
/** Copy from the temporary file to the real file */
private void append()
{
// We could write directly to the real file if:
// we record the truncate point needed for an abort
// manage partial final writes
// deny the existence of nodes after the transaction mark.
// Later - stay simple for now.
// Truncate/position the ObjectFile.
base.reposition(otherAllocOffset) ;
Iterator<Pair<Long, ByteBuffer>> iter = transObjects.all() ;
for ( ; iter.hasNext() ; )
{
Pair<Long, ByteBuffer> p = iter.next() ;
String s = StrUtils.fromUTF8bytes(p.getRight().array()) ;
long x = base.write(p.getRight()) ;
if ( p.getLeft()+otherAllocOffset != x )
throw new FileException("Expected id of "+(p.getLeft()+otherAllocOffset)+", got an id of "+x) ;
}
}
//public void setPassthrough(boolean v) { passthrough = v ; }
@Override
public void reposition(long id)
{
if ( passthrough ) { base.reposition(id) ; return ; }
if ( id > otherAllocOffset )
{
transObjects.reposition(mapToOther(id)) ;
return ;
}
Log.warn(this, "Unexpected: Attempt to reposition over base file") ;
base.reposition(id) ;
transObjects.reposition(0) ;
otherAllocOffset = base.length() ;
}
@Override
public void truncate(long id)
{
if ( passthrough ) { base.truncate(id) ; return ; }
if ( id > otherAllocOffset )
{
transObjects.truncate(mapToOther(id)) ;
return ;
}
base.truncate(id) ;
transObjects.truncate(0) ;
otherAllocOffset = base.length() ;
}
@Override
public Block allocWrite(int maxBytes)
{
if ( passthrough ) return base.allocWrite(maxBytes) ;
Block block = transObjects.allocWrite(maxBytes) ;
block = new Block(block.getId()+otherAllocOffset, block.getByteBuffer()) ;
return block ;
}
@Override
public void completeWrite(Block block)
{
if ( passthrough ) { base.completeWrite(block) ; return ; }
block = new Block(block.getId()-otherAllocOffset, block.getByteBuffer()) ;
transObjects.completeWrite(block) ;
}
@Override
public void abortWrite(Block block)
{
if ( passthrough ) { base.abortWrite(block) ; return ; }
block = new Block(block.getId()-otherAllocOffset, block.getByteBuffer()) ;
transObjects.abortWrite(block) ;
}
/** Convert from a id to the id in the "other" file */
private long mapToOther(long x) { return x-otherAllocOffset ; }
/** Convert from a id in other to an external id */
private long mapFromOther(long x) { return x+otherAllocOffset ; }
@Override
public long write(ByteBuffer buffer)
{
if ( passthrough ) { return base.write(buffer) ; }
// Write to auxillary
long x = transObjects.write(buffer) ;
return mapFromOther(x) ;
}
@Override
public ByteBuffer read(long id)
{
if ( passthrough ) { return base.read(id) ; }
if ( id < otherAllocOffset )
return base.read(id) ;
long x = mapToOther(id) ;
return transObjects.read(id-otherAllocOffset) ;
}
@Override
public long length()
{
if ( passthrough ) { return base.length() ; }
return otherAllocOffset+transObjects.length() ;
}
@Override
public boolean isEmpty()
{
if ( passthrough ) { return base.isEmpty() ; }
return transObjects.isEmpty() && base.isEmpty() ;
}
@Override
public Iterator<Pair<Long, ByteBuffer>> all()
{
if ( passthrough ) { return base.all() ; }
return Iter.concat(base.all(), transObjects.all()) ;
}
@Override
public void sync()
{
if ( passthrough ) { base.sync() ; return ; }
}
@Override
public void close()
{
if ( passthrough ) { base.close() ; return ; }
}
@Override
public String getLabel()
{
return "("+base.getLabel()+":"+transObjects.getLabel()+")" ;
}
}