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HSQLDB - Lightweight 100% Java SQL Database Engine
/* Copyright (c) 2001-2019, The HSQL Development Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the HSQL Development Group nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.hsqldb.persist;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import org.hsqldb.Database;
import org.hsqldb.lib.HsqlByteArrayOutputStream;
import org.hsqldb.lib.InputStreamInterface;
import org.hsqldb.lib.java.JavaSystem;
import org.hsqldb.map.BitMap;
/*
* Wrapper for random access file for incremental backup of the .data file.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 2.5.0
* @since 1.9.0
*/
public class RAShadowFile {
private static final int headerSize = 12;
final EventLogInterface logger;
final String pathName;
final RandomAccessInterface source;
RandomAccessInterface dest;
final int pageSize;
final long maxSize;
final BitMap bitMap;
boolean zeroPageSet;
long savedLength;
long synchLength;
byte[] buffer;
HsqlByteArrayOutputStream byteArrayOutputStream;
RAShadowFile(EventLogInterface logger, RandomAccessInterface source,
String pathName, long maxSize, int pageSize) {
this.logger = logger;
this.pathName = pathName;
this.source = source;
this.pageSize = pageSize;
this.maxSize = maxSize;
int bitSize = (int) (maxSize / pageSize);
if (maxSize % pageSize != 0) {
bitSize++;
}
bitMap = new BitMap(bitSize, false);
buffer = new byte[pageSize + headerSize];
byteArrayOutputStream = new HsqlByteArrayOutputStream(buffer);
}
int copy(long fileOffset, int size) throws IOException {
// always copy the first page
int pageCount = 0;
if (!zeroPageSet) {
pageCount += copy(0);
bitMap.set(0);
zeroPageSet = true;
}
if (fileOffset >= maxSize) {
return pageCount;
}
long endOffset = fileOffset + size;
if (endOffset > maxSize) {
endOffset = maxSize;
}
int startPageOffset = (int) (fileOffset / pageSize);
int endPageOffset = (int) (endOffset / pageSize);
if (endOffset % pageSize == 0) {
endPageOffset--;
}
for (; startPageOffset <= endPageOffset; startPageOffset++) {
pageCount += copy(startPageOffset);
}
return pageCount;
}
private int copy(int pageOffset) throws IOException {
if (bitMap.set(pageOffset) == 1) {
return 0;
}
long position = (long) pageOffset * pageSize;
int readSize = pageSize;
int writeSize = buffer.length;
if (maxSize - position < pageSize) {
readSize = (int) (maxSize - position);
}
if (dest == null) {
open();
}
long writePos = dest.length();
try {
byteArrayOutputStream.reset();
if (readSize < pageSize) {
byteArrayOutputStream.fill(0, buffer.length);
byteArrayOutputStream.reset();
}
byteArrayOutputStream.writeInt(pageSize);
byteArrayOutputStream.writeLong(position);
source.seek(position);
source.read(buffer, headerSize, readSize);
dest.seek(writePos);
dest.write(buffer, 0, writeSize);
savedLength = writePos + writeSize;
return 1;
} catch (Throwable t) {
bitMap.unset(pageOffset);
dest.seek(0);
dest.setLength(writePos);
close();
logger.logSevereEvent("shadow backup failure pos " + position
+ " " + readSize, t);
throw JavaSystem.toIOException(t);
}
}
private void open() throws IOException {
dest = new RAFileSimple(logger, pathName, "rw");
}
/**
* Called externally after a series of copy() calls.
* Called internally after a restore or when error in writing
*/
void close() throws IOException {
if (dest != null) {
dest.synch();
dest.close();
dest = null;
}
}
public void synch() {
if (dest != null) {
dest.synch();
synchLength = savedLength;
}
}
public long getSavedLength() {
return savedLength;
}
public InputStreamInterface getInputStream() {
return new InputStreamShadow();
}
private static RandomAccessInterface getStorage(Database database,
String pathName, String openMode) throws IOException {
return new RAFileSimple(database.logger, pathName, openMode);
}
/** todo - take account of incomplete addition of block due to lack of disk */
// buggy database files had size == position == 0 at the end
public static void restoreFile(Database database, String sourceName,
String destName) throws IOException {
RandomAccessInterface source = getStorage(database, sourceName, "r");
RandomAccessInterface dest = getStorage(database, destName, "rw");
while (source.getFilePointer() != source.length()) {
int size = source.readInt();
long position = source.readLong();
byte[] buffer = new byte[size];
source.read(buffer, 0, buffer.length);
dest.seek(position);
dest.write(buffer, 0, buffer.length);
}
source.close();
dest.synch();
dest.close();
}
class InputStreamShadow implements InputStreamInterface {
FileInputStream is;
long limitSize = 0;
long fetchedSize = 0;
boolean initialised = false;
public int read() throws IOException {
if (!initialised) {
initialise();
}
if (fetchedSize == limitSize) {
return -1;
}
int byteread = is.read();
if (byteread < 0) {
throw new IOException("backup file not complete "
+ fetchedSize + " " + limitSize);
}
fetchedSize++;
return byteread;
}
public int read(byte[] bytes) throws IOException {
return read(bytes, 0, bytes.length);
}
public int read(byte[] bytes, int offset,
int length) throws IOException {
if (!initialised) {
initialise();
}
if (fetchedSize == limitSize) {
return -1;
}
if (limitSize >= 0 && limitSize - fetchedSize < length) {
length = (int) (limitSize - fetchedSize);
}
int count = is.read(bytes, offset, length);
if (count < 0) {
throw new IOException("backup file not complete "
+ fetchedSize + " " + limitSize);
}
fetchedSize += count;
return count;
}
public long skip(long count) throws IOException {
return 0;
}
public int available() throws IOException {
return 0;
}
public void close() throws IOException {
if (is != null) {
is.close();
}
}
public void setSizeLimit(long count) {
limitSize = count;
}
public long getSizeLimit() {
if (!initialised) {
initialise();
}
return limitSize;
}
private void initialise() {
limitSize = synchLength;
logger.logDetailEvent("shadow file size for backup: " + limitSize);
if (limitSize > 0) {
try {
is = new FileInputStream(pathName);
} catch (FileNotFoundException e) {}
}
initialised = true;
}
}
}