/*
 * eXist Open Source Native XML Database
 * Copyright (C) 2001-2015 The eXist Project
 *
 * http://exist-db.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
package org.exist.storage.dom;

import java.nio.ByteBuffer;

import org.exist.storage.DBBroker;
import org.exist.storage.NativeBroker;
import org.exist.storage.journal.AbstractLoggable;
import org.exist.storage.journal.LogException;
import org.exist.storage.txn.Txn;

/**
 * @author wolf
 */
public class UpdateValueLoggable extends AbstractLoggable {
    protected DOMFile domDb;
    protected long pageNum;
    protected short tid;
    protected byte[] value;
    protected byte[] oldValue;
    protected int oldOffset;

    public UpdateValueLoggable(final Txn transaction, final long pageNum, final short tid,
                               final byte[] value, final byte[] oldValue, final int oldOffset) {
        super(DOMFile.LOG_UPDATE_VALUE, transaction.getId());
        this.pageNum = pageNum;
        this.tid = tid;
        this.value = value;
        this.oldValue = oldValue;
        this.oldOffset = oldOffset;
    }

    public UpdateValueLoggable(final DBBroker broker, final long transactionId) {
        super(DOMFile.LOG_UPDATE_VALUE, transactionId);
        this.domDb = ((NativeBroker) broker).getDOMFile();
    }

    @Override
    public void write(final ByteBuffer out) {
        out.putInt((int) pageNum);
        out.putShort(tid);
        out.putShort((short) value.length);
        out.put(value);
        out.putShort((short) oldOffset);
        out.put(oldValue, oldOffset, value.length);
    }

    @Override
    public void read(final ByteBuffer in) {
        pageNum = in.getInt();
        tid = in.getShort();
        value = new byte[in.getShort()];
        in.get(value);
        oldOffset = in.getShort();
        oldValue = new byte[value.length];
        in.get(oldValue);
    }

    @Override
    public int getLogSize() {
        return 10 + (value.length * 2);
    }

    @Override
    public void redo() throws LogException {
        domDb.redoUpdateValue(this);
    }

    @Override
    public void undo() throws LogException {
        domDb.undoUpdateValue(this);
    }

    @Override
    public String dump() {
        return super.dump() + " - updated value; tid = " + ItemId.getId(tid) + " to page " + pageNum;
    }
}