org.apache.tools.ant.taskdefs.Truncate Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.tools.ant.taskdefs;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Iterator;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceCollection;
import org.apache.tools.ant.types.resources.FileProvider;
import org.apache.tools.ant.types.resources.FileResource;
import org.apache.tools.ant.util.FileUtils;
/**
* Set the length of one or more files, as the intermittently available
* truncate Unix utility/function.
* @since Ant 1.7.1
*/
public class Truncate extends Task {
private static final int BUFFER_SIZE = 1024;
private static final Long ZERO = new Long(0L);
private static final String NO_CHILD = "No files specified.";
private static final String INVALID_LENGTH = "Cannot truncate to length ";
private static final String READ_WRITE = "rw";
private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();
private static final byte[] FILL_BUFFER = new byte[BUFFER_SIZE];
private Path path;
private boolean create = true;
private boolean mkdirs = false;
private Long length;
private Long adjust;
/**
* Set a single target File.
* @param f the single File
*/
public void setFile(File f) {
add(new FileResource(f));
}
/**
* Add a nested (filesystem-only) ResourceCollection.
* @param rc the ResourceCollection to add.
*/
public void add(ResourceCollection rc) {
getPath().add(rc);
}
/**
* Set the amount by which files' lengths should be adjusted.
* It is permissible to append K / M / G / T / P.
* @param adjust (positive or negative) adjustment amount.
*/
public void setAdjust(Long adjust) {
this.adjust = adjust;
}
/**
* Set the length to which files should be set.
* It is permissible to append K / M / G / T / P.
* @param length (positive) adjustment amount.
*/
public void setLength(Long length) {
this.length = length;
if (length != null && length.longValue() < 0) {
throw new BuildException(INVALID_LENGTH + length);
}
}
/**
* Set whether to create nonexistent files.
* @param create boolean, default true.
*/
public void setCreate(boolean create) {
this.create = create;
}
/**
* Set whether, when creating nonexistent files, nonexistent directories
* should also be created.
* @param mkdirs boolean, default false.
*/
public void setMkdirs(boolean mkdirs) {
this.mkdirs = mkdirs;
}
/** {@inheritDoc}. */
public void execute() {
if (length != null && adjust != null) {
throw new BuildException(
"length and adjust are mutually exclusive options");
}
if (length == null && adjust == null) {
length = ZERO;
}
if (path == null) {
throw new BuildException(NO_CHILD);
}
for (Iterator it = path.iterator(); it.hasNext();) {
Resource r = (Resource) it.next();
File f = ((FileProvider) r.as(FileProvider.class)).getFile();
if (shouldProcess(f)) {
process(f);
}
}
}
private boolean shouldProcess(File f) {
if (f.isFile()) {
return true;
}
if (!create) {
return false;
}
Exception exception = null;
try {
if (FILE_UTILS.createNewFile(f, mkdirs)) {
return true;
}
} catch (IOException e) {
exception = e;
}
String msg = "Unable to create " + f;
if (exception == null) {
log(msg, Project.MSG_WARN);
return false;
}
throw new BuildException(msg, exception);
}
private void process(File f) {
long len = f.length();
long newLength = length == null
? len + adjust.longValue() : length.longValue();
if (len == newLength) {
//nothing to do!
return;
}
RandomAccessFile raf = null;
try {
raf = new RandomAccessFile(f, READ_WRITE);
} catch (Exception e) {
throw new BuildException("Could not open " + f + " for writing", e);
}
try {
if (newLength > len) {
long pos = len;
raf.seek(pos);
while (pos < newLength) {
long writeCount = Math.min(FILL_BUFFER.length,
newLength - pos);
raf.write(FILL_BUFFER, 0, (int) writeCount);
pos += writeCount;
}
} else {
raf.setLength(newLength);
}
} catch (IOException e) {
throw new BuildException("Exception working with " + raf, e);
} finally {
try {
raf.close();
} catch (IOException e) {
log("Caught " + e + " closing " + raf, Project.MSG_WARN);
}
}
}
private synchronized Path getPath() {
if (path == null) {
path = new Path(getProject());
}
return path;
}
}