/*
* Copyright (C) 2006 http://www.chaidb.org
*
* 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.
*
* 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.
*
*/
package org.chaidb.db.log.logrecord;
import org.apache.log4j.Logger;
import org.chaidb.db.exception.ChaiDBException;
import org.chaidb.db.exception.ErrorCode;
import org.chaidb.db.helper.ByteTool;
import org.chaidb.db.index.btree.BTree;
import org.chaidb.db.index.btree.BTreeSpec;
import org.chaidb.db.index.btree.bufmgr.PageBufferManager;
import org.chaidb.db.log.LogRecord;
/**
* allocate a new page while BtreePage(or DataPage) newPage()
* log the new allocated page number
*/
public class BTreeNewPageLogRecord extends BTreeLogRecord {
private static PageBufferManager bpm = PageBufferManager.getInstance();
private static final Logger logger = Logger.getLogger(BTreeNewPageLogRecord.class);
private byte pageFlag; //page flags
static int PAGEFLAG_SIZE = 1; //1 bytes
private int docId;
/**
* default Construct
*/
public BTreeNewPageLogRecord() {
super();
super.setType(LOG_BTREE_NEW_PAGE);
}
/**
* Construct
*
* @param docId Only used by DataPage,excluding BTreePage and OverFlowpage
*/
public BTreeNewPageLogRecord(int treeId, int newPageNum, int newTxnId, int newPageFlag, int docId, short btreeType) {
super(treeId, newPageNum, newTxnId, btreeType);
this.pageFlag = (byte) newPageFlag;
this.docId = docId;
super.setType(LOG_BTREE_NEW_PAGE);
}
/**
* get page flag
*/
public byte getPageFlag() {
return pageFlag;
}
public int getDocId() {
return docId;
}
/**
* converts a byte array into a log record instance
*/
public boolean read(byte[] bArr, int start) throws ChaiDBException {
/* construct a new LogRecord instance */
super.read(bArr, start);
/* get the values of BTreeMoveLogRecord Object */
int step = start + super.getRecordLength();
pageFlag = bArr[step];
if (isDataPage(pageFlag)) {
byte tmpByte = bArr[step];
bArr[step] = 0;
docId = ByteTool.bytesToInt(bArr, step, LogRecord.msbFirst);
bArr[step] = tmpByte;
}
return true;
}
/**
* redo allocate a new page function
*
* @param page
* @return boolean true|false
* update date:2001-10-12 by marriane,delete freelist recover
*/
protected boolean doRedo(byte[] page) throws ChaiDBException {
try {
/* set metadata's lowbound and uppbound data with default value */
System.arraycopy(ByteTool.shortToBytes((short) BTreeSpec.PAGE_HEADER_SIZE), 0, page, BTreeSpec.OFF_LOWERBOUND, 2);
System.arraycopy(ByteTool.shortToBytes((short) BTreeSpec.PAGE_SIZE), 0, page, BTreeSpec.OFF_UPPERBOUND, 2);
/* set metadata's pageNumber */
System.arraycopy(ByteTool.intToBytes(super.getPageNum()), 0, page, BTreeSpec.OFF_PAGENUMBER, 4);
/* set prevPage and nextPage in metadata */
System.arraycopy(ByteTool.intToBytes(BTreeSpec.INVALID_PAGENO), 0, page, BTreeSpec.OFF_PREVPAGE, 4);
System.arraycopy(ByteTool.intToBytes(BTreeSpec.INVALID_PAGENO), 0, page, BTreeSpec.OFF_NEXTPAGE, 4);
/* set flags of different page type */
System.arraycopy(ByteTool.intToBytes(pageFlag), 0, page, BTreeSpec.OFF_FLAGS, 4);
} catch (Exception e) {
logger.debug(e);
throw new ChaiDBException(ErrorCode.LOG_REDO_FAILED, e.toString());
}
return true;
}
/**
* do undo function
*
* @param page
* @return boolean true|false
* update date:2001-10-12 by marriane,delete freelist recover
*/
protected boolean doUndo(byte[] page) throws ChaiDBException {
try {
/* set metadata's lowbound and uppbound data with default value */
System.arraycopy(ByteTool.shortToBytes((short) BTreeSpec.PAGE_HEADER_SIZE), 0, page, BTreeSpec.OFF_LOWERBOUND, 2);
System.arraycopy(ByteTool.shortToBytes((short) BTreeSpec.PAGE_SIZE), 0, page, BTreeSpec.OFF_UPPERBOUND, 2);
/* add page to freelist of BufferedPage in memory*/
PageBufferManager bp = bpm;
bp.addToFreeList(treeId, super.getPageNum(), new Integer(super.getTxnId()));
if (isDataPage(pageFlag))
bp.removeLatestDataPage(docId, treeId, super.getPageNum(), new Integer(super.getTxnId()));
//add 1 on the free page number in metadata page of file if it's not in freelist
} catch (Exception e) {
logger.debug(e);
throw new ChaiDBException(ErrorCode.LOG_UNDO_FAILED, e.toString());
}
return true;
}
/**
* print data and help in debugging log files
*/
public void print() throws ChaiDBException {
//logger.log(ServerLog.LOG_DEBUG,"begin: printing the information of BTreeNewPageLogRecord object......");
super.print();
logger.debug(" flag:" + this.getPageFlag());
//logger.log(ServerLog.LOG_DEBUG,"end: printing the information of BTreeNewPageLogRecord object.");
}
/**
* converts a log record instance into a byte array.
* The byte array has the following format:
* --------------------------------------------------
* | pageFlag
* --------------------------------------------------
* <p/>
* pageFlag: 1 bytes.
*/
public void toBytes(byte[] byteArray, int start) throws ChaiDBException {
super.toBytes(byteArray, start);
int step = start + super.getRecordLength();
byteArray[step] = pageFlag;
if (super.isDataPage(pageFlag)) {
byte[] docIdArr = ByteTool.intToBytes(docId, LogRecord.msbFirst);
System.arraycopy(docIdArr, docIdArr.length - BTree.DOCID_SIZE, byteArray, ++step, BTree.DOCID_SIZE);
}
}
/**
* get current log record type total length
*
* @return int total lenth
*/
public int getRecordLength() {
return super.getRecordLength() + PAGEFLAG_SIZE + (isDataPage(pageFlag) ? BTree.DOCID_SIZE : 0);
}
}