/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Ant", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 THE APACHE SOFTWARE FOUNDATION OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.tools.ant.taskdefs;

import org.apache.tools.ant.*;

import java.io.*;
import java.util.zip.*;

/**
 * Expands a file that has been compressed with the GZIP
 * algorightm. Normally used to compress non-compressed archives such
 * as TAR files.
 *
 * @author Stefan Bodewig <a href="mailto:stefan.bodewig@megabit.net">stefan.bodewig@megabit.net</a>
 */

public class GUnzip extends Task {

    private File source;
    private File dest;

    public void setSrc(String src) {
        source = project.resolveFile(src);
    }

    public void setDest(String dest) {
        this.dest = project.resolveFile(dest);
    }

    public void execute() throws BuildException {
        if (source == null) {
            throw new BuildException("No source for gunzip specified", location);
        }

        if (!source.exists()) {
            throw new BuildException("source doesn't exist", location);
        }

        if (source.isDirectory()) {
            throw new BuildException("Cannot expand a directory", location);
        }

        if (dest == null) {
            dest = new File(source.getParent());
        }

        if (dest.isDirectory()) {
            String sourceName = source.getName();
            int len = sourceName.length();
            if (len > 3
                && ".gz".equalsIgnoreCase(sourceName.substring(len-3))) {
                dest = new File(dest, sourceName.substring(0, len-3));
            } else {
                dest = new File(dest, sourceName);
            }
        }

        if (source.lastModified() > dest.lastModified()) {
            log("Expanding "+ source.getAbsolutePath() + " to "
                        + dest.getAbsolutePath());

            FileOutputStream out = null;
            GZIPInputStream zIn = null;
            try {
                out = new FileOutputStream(dest);
                zIn = new GZIPInputStream(new FileInputStream(source));
                byte[] buffer = new byte[8 * 1024];
                int count = 0;
                do {
                    out.write(buffer, 0, count);
                    count = zIn.read(buffer, 0, buffer.length);
                } while (count != -1);
            } catch (IOException ioe) {
                String msg = "Problem expanding gzip " + ioe.getMessage();
                throw new BuildException(msg, ioe, location);
            } finally {
                if (out != null) {
                    try {
                        out.close();
                    } catch (IOException ioex) {}
                }
                if (zIn != null) {
                    try {
                        zIn.close();
                    } catch (IOException ioex) {}
                }
            }
        }
    }
}