/*
* The MIT License
*
* Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package hudson.util;
import hudson.Util;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
/**
* Represents write-once read-many file that can be optiionally compressed
* to save disk space. This is used for console output and other bulky data.
*
* <p>
* In this class, the data on the disk can be one of two states:
* <ol>
* <li>Uncompressed, in which case the original data is available in the specified file name.
* <li>Compressed, in which case the gzip-compressed data is available in the specifiled file name + ".gz" extension.
* </ol>
*
* Once the file is written and completed, it can be compressed asynchronously
* by {@link #compress()}.
*
* @author Kohsuke Kawaguchi
*/
public class CompressedFile {
/**
* The name of the raw file.
*/
private final File file;
/**
* The name of the compressed file.
*/
private final File gz;
public CompressedFile(File file) {
this.file = file;
this.gz = new File(file.getParentFile(),file.getName()+".gz");
}
/**
* Gets the OutputStream to write to the file.
*/
public OutputStream write() throws FileNotFoundException {
if(gz.exists())
gz.delete();
return new FileOutputStream(file);
}
/**
* Reads the contents of a file.
*/
public InputStream read() throws IOException {
if(file.exists())
return new FileInputStream(file);
// check if the compressed file exists
if(gz.exists())
return new GZIPInputStream(new FileInputStream(gz));
// no such file
throw new FileNotFoundException(file.getName());
}
/**
* Loads the file content as a string.
*/
public String loadAsString() throws IOException {
long sizeGuess;
if(file.exists())
sizeGuess = file.length();
else
if(gz.exists())
sizeGuess = gz.length()*2;
else
return "";
StringBuilder str = new StringBuilder((int)sizeGuess);
Reader r = new InputStreamReader(read());
char[] buf = new char[8192];
int len;
while((len=r.read(buf,0,buf.length))>0)
str.append(buf,0,len);
r.close();
return str.toString();
}
/**
* Asynchronously schedules the compression of this file.
*
* <p>
* Once the file is compressed, the original will be removed and
* the further reading will be done from the compressed stream.
*/
public void compress() {
compressionThread.submit(new Runnable() {
public void run() {
try {
InputStream in = read();
OutputStream out = new GZIPOutputStream(new FileOutputStream(gz));
try {
Util.copyStream(in,out);
} finally {
in.close();
out.close();
}
// if the compressed file is created successfully, remove the original
file.delete();
} catch (IOException e) {
LOGGER.log(Level.WARNING, "Failed to compress "+file,e);
gz.delete(); // in case a processing is left in the middle
}
}
});
}
/**
* Executor used for compression. Limited up to one thread since
* this should be a fairly low-priority task.
*/
private static final ExecutorService compressionThread = new ThreadPoolExecutor(
0, 1, 5L, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(),
new ExceptionCatchingThreadFactory(new DaemonThreadFactory()));
private static final Logger LOGGER = Logger.getLogger(CompressedFile.class.getName());
}