org.hsqldb.lib.tar.TarFileOutputStream Maven / Gradle / Ivy
/* Copyright (c) 2001-2014, 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.lib.tar;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;
/**
* Note that this class is not a java.io.FileOutputStream,
* because our goal is to greatly restrict the public methods of
* FileOutputStream, yet we must use public methods of the underlying
* FileOutputStream internally. Can't accomplish these goals in Java if we
* subclass.
*
* This class is ignorant about Tar header fields, attributes and such.
* It is concerned with reading and writing blocks of data in conformance with
* Tar formatting, in a way convenient to those who want to write the header
* and data blocks.
*
* Users write file data by means of populating the provided, public byte array,
* then calling the single write(int) method to write a portion of that array.
* This design purposefully goes with efficiency, simplicity, and performance
* over Java convention, which would not use public fields.
*
* At this time, we do not support appending. That would greatly decrease the
* generality and simplicity of the our design, since appending is trivial
* without compression and very difficult with compression.
*
* Users must finish tar file creation by using the finish() method.
* Just like a normal OutputStream, if processing is aborted for any reason,
* the close() method must be used to free up system resources.
*
* SECURITY NOTE
* Due to pitiful lack of support for file security in Java before version 1.6,
* this class will only explicitly set permissions if it is compiled for Java
* 1.6. If it was not, and if your tar entries contain private data in files
* with 0400 or similar, be aware that that file can be pretty much be
* extracted by anybody with access to the tar file.
*
*
* @see #finish
* @see #close
*/
public class TarFileOutputStream {
public interface Compression {
int NO_COMPRESSION = 0;
int GZIP_COMPRESSION = 1;
int DEFAULT_COMPRESSION = NO_COMPRESSION;
int DEFAULT_BLOCKS_PER_RECORD = 20;
}
public static final boolean debug = Boolean.getBoolean("DEBUG");
protected int blocksPerRecord;
protected long bytesWritten = 0;
private OutputStream writeStream;
private File targetFile;
private File writeFile;
/* This is not a "Writer", but the byte "Stream" that we write() to. */
public byte[] writeBuffer;
/* We purposefully provide no public getter or setter for writeBuffer.
* No getter because the whole point of this class is that the byte
* array is a direct, optimally efficient byte array. No setter because
* the inside implementation of this class is intimately dependent upon
* the nature of the write buffer. */
static final byte[] ZERO_BLOCK = new byte[512];
/**
* Convenience wrapper to use default blocksPerRecord and compressionType.
*
* @see #TarFileOutputStream(File, int, int)
*/
public TarFileOutputStream(File targetFile) throws IOException {
this(targetFile, Compression.DEFAULT_COMPRESSION);
}
/**
* Convenience wrapper to use default blocksPerRecord.
*
* @see #TarFileOutputStream(File, int, int)
*/
public TarFileOutputStream(File targetFile,
int compressionType) throws IOException {
this(targetFile, compressionType,
TarFileOutputStream.Compression.DEFAULT_BLOCKS_PER_RECORD);
}
/**
* This class does no validation or enforcement of file naming conventions.
* If desired, the caller should enforce extensions like "tar" and
* "tar.gz" (and that they match the specified compression type).
*
* It also overwrites files without warning (just like FileOutputStream).
*/
public TarFileOutputStream(File targetFile, int compressionType,
int blocksPerRecord) throws IOException {
this.blocksPerRecord = blocksPerRecord;
this.targetFile = targetFile;
writeFile = new File(targetFile.getParentFile(),
targetFile.getName() + "-partial");
if (this.writeFile.exists()) {
throw new IOException(
RB.move_work_file.getString(writeFile.getAbsolutePath()));
}
if (targetFile.exists() && !targetFile.canWrite()) {
throw new IOException(
RB.cant_overwrite.getString(targetFile.getAbsolutePath()));
}
File parentDir = targetFile.getAbsoluteFile().getParentFile();
if (parentDir.exists() && parentDir.isDirectory()) {
if (!parentDir.canWrite()) {
throw new IOException(
RB.cant_write_dir.getString(parentDir.getAbsolutePath()));
}
} else {
throw new IOException(
RB.no_parent_dir.getString(parentDir.getAbsolutePath()));
}
writeBuffer = new byte[blocksPerRecord * 512];
switch (compressionType) {
case TarFileOutputStream.Compression.NO_COMPRESSION :
writeStream = new FileOutputStream(writeFile);
break;
case TarFileOutputStream.Compression.GZIP_COMPRESSION :
writeStream =
new GZIPOutputStream(new FileOutputStream(writeFile),
writeBuffer.length);
break;
default :
throw new IllegalArgumentException(
RB.compression_unknown.getString(compressionType));
}
//#ifdef JAVA6
writeFile.setExecutable(false, true);
writeFile.setExecutable(false, false);
writeFile.setReadable(false, false);
writeFile.setReadable(true, true);
writeFile.setWritable(false, false);
writeFile.setWritable(true, true);
//#endif
// We restrict permissions to the file owner before writing
// anything, in case we will be writing anything private into this
// file.
}
/**
* This class and subclasses should write to the underlying writeStream
* ONLY WITH THIS METHOD.
* That way we can be confident that bytesWritten will always be accurate.
*/
public void write(byte[] byteArray, int byteCount) throws IOException {
writeStream.write(byteArray, 0, byteCount);
bytesWritten += byteCount;
}
/**
* The normal way to write file data (as opposed to header data or padding)
* using this class.
*/
public void write(int byteCount) throws IOException {
write(writeBuffer, byteCount);
}
/**
* Write a user-specified 512-byte block.
* For efficiency, write(int) should be used when writing file body content.
*
* @see #write(int)
*/
public void writeBlock(byte[] block) throws IOException {
if (block.length != 512) {
throw new IllegalArgumentException(
RB.bad_block_write_len.getString(block.length));
}
write(block, block.length);
}
/**
* Writes the specified quantity of zero'd blocks.
*/
public void writePadBlocks(int blockCount) throws IOException {
for (int i = 0; i < blockCount; i++) {
write(ZERO_BLOCK, ZERO_BLOCK.length);
}
}
/**
* Writes a single zero'd block.
*/
public void writePadBlock() throws IOException {
writePadBlocks(1);
}
public int bytesLeftInBlock() {
int modulus = (int) (bytesWritten % 512L);
if (modulus == 0) {
return 0;
}
return 512 - modulus;
}
/**
* @throws IllegalStateException if end of file not on a block boundary.
*/
public void assertAtBlockBoundary() {
if (bytesLeftInBlock() != 0) {
throw new IllegalArgumentException(
RB.illegal_block_boundary.getString(
Long.toString(bytesWritten)));
}
}
/**
* Rounds out the current block to the next block bondary.
* If we are currently at a block boundary, nothing is done.
*/
public void padCurrentBlock() throws IOException {
int padBytes = bytesLeftInBlock();
if (padBytes == 0) {
return;
}
write(ZERO_BLOCK, padBytes);
// REMOVE THIS DEV-ASSERTION:
assertAtBlockBoundary();
}
/**
* Implements java.io.Flushable.
*
* @see java.io.Flushable
*/
public void flush() throws IOException {
writeStream.flush();
}
/**
* Implements java.io.Closeable.
*
* IMPORTANT: This method deletes the work file after
* closing it!
*
* @see java.io.Closeable
*/
public void close() throws IOException {
if (writeStream == null) {
return;
}
try {
writeStream.close();
if (!writeFile.delete()) {
throw new IOException(
RB.workfile_delete_fail.getString(
writeFile.getAbsolutePath()));
}
} finally {
writeStream = null; // Encourage buffer GC
}
}
public long getBytesWritten() {
return bytesWritten;
}
/**
* (Only) when this method returns successfully, the generated file will be
* a valid tar file.
*
* This method always performs a close, so you never need to call the close
* if your code makes it to this method.
* (You do need to call close if processing is aborted before calling
* finish()).
*
* @see #close
*/
public void finish() throws IOException {
try {
long finalBlock = bytesWritten / 512 + 2;
if (finalBlock % blocksPerRecord != 0) {
// Round up total archive size to a blocksPerRecord multiple
finalBlock = (finalBlock / blocksPerRecord + 1)
* blocksPerRecord;
}
int finalPadBlocks = (int) (finalBlock - bytesWritten / 512L);
if (TarFileOutputStream.debug) {
System.out.println(
RB.pad_block_write.getString(finalPadBlocks));
}
writePadBlocks(finalPadBlocks);
} catch (IOException ioe) {
try {
close();
} catch (IOException ne) {
// Too difficult to report every single error.
// More important that the user know about the original Exc.
}
throw ioe;
}
writeStream.close();
writeFile.renameTo(targetFile);
}
}
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