/*
 * Copyright  2000-2004 The Apache Software Foundation
 *
 *  Licensed 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.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Stack;
import java.util.Vector;
import java.util.zip.CRC32;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.DirectoryScanner;
import org.apache.tools.ant.FileScanner;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.types.EnumeratedAttribute;
import org.apache.tools.ant.types.FileSet;
import org.apache.tools.ant.types.PatternSet;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ZipFileSet;
import org.apache.tools.ant.types.ZipScanner;
import org.apache.tools.ant.util.FileNameMapper;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.util.GlobPatternMapper;
import org.apache.tools.ant.util.IdentityMapper;
import org.apache.tools.ant.util.MergingMapper;
import org.apache.tools.ant.util.ResourceUtils;
import org.apache.tools.zip.ZipEntry;
import org.apache.tools.zip.ZipFile;
import org.apache.tools.zip.ZipOutputStream;

/**
 * Create a Zip file.
 *
 * @since Ant 1.1
 *
 * @ant.task category="packaging"
 */
public class Zip extends MatchingTask {

    protected File zipFile;
    // use to scan own archive
    private ZipScanner zs;
    private File baseDir;
    protected Hashtable entries = new Hashtable();
    private Vector groupfilesets = new Vector();
    private Vector filesetsFromGroupfilesets = new Vector();
    protected String duplicate = "add";
    private boolean doCompress = true;
    private boolean doUpdate = false;
    // shadow of the above if the value is altered in execute
    private boolean savedDoUpdate = false;
    private boolean doFilesonly = false;
    protected String archiveType = "zip";

    // For directories:
    private static final long EMPTY_CRC = new CRC32 ().getValue ();
    protected String emptyBehavior = "skip";
    private Vector filesets = new Vector ();
    protected Hashtable addedDirs = new Hashtable();
    private Vector addedFiles = new Vector();

    protected boolean doubleFilePass = false;
    protected boolean skipWriting = false;

    private static FileUtils fileUtils = FileUtils.newFileUtils();

    /**
     * true when we are adding new files into the Zip file, as opposed
     * to adding back the unchanged files
     */
    private boolean addingNewFiles = false;

    /**
     * Encoding to use for filenames, defaults to the platform's
     * default encoding.
     */
    private String encoding;

    /**
     * Whether the original compression of entries coming from a ZIP
     * archive should be kept (for example when updating an archive).
     *
     * @since Ant 1.6
     */
    private boolean keepCompression = false;

    /**
     * Whether the file modification times will be rounded up to the
     * next even number of seconds.
     *
     * @since Ant 1.6.2
     */
    private boolean roundUp = true;

    /**
     * This is the name/location of where to
     * create the .zip file.
     *
     * @deprecated Use setDestFile(File) instead.
     * @ant.attribute ignore="true"
     */
    public void setZipfile(File zipFile) {
        setDestFile(zipFile);
    }

    /**
     * This is the name/location of where to
     * create the file.
     * @since Ant 1.5
     * @deprecated Use setDestFile(File) instead
     * @ant.attribute ignore="true"
     */
    public void setFile(File file) {
        setDestFile(file);
    }


    /**
     * The file to create; required.
     * @since Ant 1.5
     * @param destFile The new destination File
     */
    public void setDestFile(File destFile) {
       this.zipFile = destFile;
    }

    /**
     * The file to create.
     * @since Ant 1.5.2
     */
    public File getDestFile() {
        return zipFile;
    }


    /**
     * Directory from which to archive files; optional.
     */
    public void setBasedir(File baseDir) {
        this.baseDir = baseDir;
    }

    /**
     * Whether we want to compress the files or only store them;
     * optional, default=true;
     */
    public void setCompress(boolean c) {
        doCompress = c;
    }

    /**
     * Whether we want to compress the files or only store them;
     *
     * @since Ant 1.5.2
     */
    public boolean isCompress() {
        return doCompress;
    }

    /**
     * If true, emulate Sun's jar utility by not adding parent directories;
     * optional, defaults to false.
     */
    public void setFilesonly(boolean f) {
        doFilesonly = f;
    }

    /**
     * If true, updates an existing file, otherwise overwrite
     * any existing one; optional defaults to false.
     */
    public void setUpdate(boolean c) {
        doUpdate = c;
        savedDoUpdate = c;
    }

    /**
     * Are we updating an existing archive?
     */
    public boolean isInUpdateMode() {
        return doUpdate;
    }

    /**
     * Adds a set of files.
     */
    public void addFileset(FileSet set) {
        filesets.addElement(set);
    }

    /**
     * Adds a set of files that can be
     * read from an archive and be given a prefix/fullpath.
     */
    public void addZipfileset(ZipFileSet set) {
        filesets.addElement(set);
    }

    /**
     * Adds a group of zip files.
     */
    public void addZipGroupFileset(FileSet set) {
        groupfilesets.addElement(set);
    }

    /**
     * Sets behavior for when a duplicate file is about to be added -
     * one of <code>keep</code>, <code>skip</code> or <code>overwrite</code>.
     * Possible values are: <code>keep</code> (keep both
     * of the files); <code>skip</code> (keep the first version
     * of the file found); <code>overwrite</code> overwrite the file
     * with the new file
     * Default for zip tasks is <code>keep</code>
     */
    public void setDuplicate(Duplicate df) {
        duplicate = df.getValue();
    }

    /**
     * Possible behaviors when there are no matching files for the task:
     * "fail", "skip", or "create".
     */
    public static class WhenEmpty extends EnumeratedAttribute {
        public String[] getValues() {
            return new String[] {"fail", "skip", "create"};
        }
    }

    /**
     * Sets behavior of the task when no files match.
     * Possible values are: <code>fail</code> (throw an exception
     * and halt the build); <code>skip</code> (do not create
     * any archive, but issue a warning); <code>create</code>
     * (make an archive with no entries).
     * Default for zip tasks is <code>skip</code>
     * for jar tasks, <code>create</code>.
     */
    public void setWhenempty(WhenEmpty we) {
        emptyBehavior = we.getValue();
    }

    /**
     * Encoding to use for filenames, defaults to the platform's
     * default encoding.
     *
     * <p>For a list of possible values see <a
     * href="http://java.sun.com/products/jdk/1.2/docs/guide/internat/encoding.doc.html">http://java.sun.com/products/jdk/1.2/docs/guide/internat/encoding.doc.html</a>.</p>
     */
    public void setEncoding(String encoding) {
        this.encoding = encoding;
    }

    /**
     * Encoding to use for filenames.
     *
     * @since Ant 1.5.2
     */
    public String getEncoding() {
        return encoding;
    }

    /**
     * Whether the original compression of entries coming from a ZIP
     * archive should be kept (for example when updating an archive).
     *
     * @since Ant 1.6
     */
    public void setKeepCompression(boolean keep) {
        keepCompression = keep;
    }

    /**
     * Whether the file modification times will be rounded up to the
     * next even number of seconds.
     *
     * <p>Zip archives store file modification times with a
     * granularity of two seconds, so the times will either be rounded
     * up or down.  If you round down, the archive will always seem
     * out-of-date when you rerun the task, so the default is to round
     * up.  Rounding up may lead to a different type of problems like
     * JSPs inside a web archive that seem to be slightly more recent
     * than precompiled pages, rendering precompilation useless.</p>
     *
     * @since Ant 1.6.2
     */
    public void setRoundUp(boolean r) {
        roundUp = r;
    }

    /**
     * validate and build
     */
    public void execute() throws BuildException {

        if (doubleFilePass) {
            skipWriting = true;
            executeMain();
            skipWriting = false;
            executeMain();
        } else {
            executeMain();
        }
    }

    public void executeMain() throws BuildException {

        if (baseDir == null && filesets.size() == 0
            && groupfilesets.size() == 0 && "zip".equals(archiveType)) {
            throw new BuildException("basedir attribute must be set, "
                                     + "or at least "
                                     + "one fileset must be given!");
        }

        if (zipFile == null) {
            throw new BuildException("You must specify the "
                                     + archiveType + " file to create!");
        }

        if (zipFile.exists() && !zipFile.isFile()) {
            throw new BuildException(zipFile + " is not a file.");
        }

        if (zipFile.exists() && !zipFile.canWrite()) {
            throw new BuildException(zipFile + " is read-only.");
        }

        // Renamed version of original file, if it exists
        File renamedFile = null;
        // Whether or not an actual update is required -
        // we don't need to update if the original file doesn't exist

        addingNewFiles = true;
        if (doUpdate && !zipFile.exists()) {
            doUpdate = false;
            log("ignoring update attribute as " + archiveType
                + " doesn't exist.", Project.MSG_DEBUG);
        }

        // Add the files found in groupfileset to fileset
        for (int i = 0; i < groupfilesets.size(); i++) {

            log("Processing groupfileset ", Project.MSG_VERBOSE);
            FileSet fs = (FileSet) groupfilesets.elementAt(i);
            FileScanner scanner = fs.getDirectoryScanner(getProject());
            String[] files = scanner.getIncludedFiles();
            File basedir = scanner.getBasedir();
            for (int j = 0; j < files.length; j++) {

                log("Adding file " + files[j] + " to fileset",
                    Project.MSG_VERBOSE);
                ZipFileSet zf = new ZipFileSet();
                zf.setProject(getProject());
                zf.setSrc(new File(basedir, files[j]));
                filesets.addElement(zf);
                filesetsFromGroupfilesets.addElement(zf);
            }
        }

        // collect filesets to pass them to getResourcesToAdd
        Vector vfss = new Vector();
        if (baseDir != null) {
            FileSet fs = (FileSet) getImplicitFileSet().clone();
            fs.setDir(baseDir);
            vfss.addElement(fs);
        }
        for (int i = 0; i < filesets.size(); i++) {
            FileSet fs = (FileSet) filesets.elementAt(i);
            vfss.addElement(fs);
        }

        FileSet[] fss = new FileSet[vfss.size()];
        vfss.copyInto(fss);
        boolean success = false;
        try {
            // can also handle empty archives
            ArchiveState state = getResourcesToAdd(fss, zipFile, false);

            // quick exit if the target is up to date
            if (!state.isOutOfDate()) {
                return;
            }

            Resource[][] addThem = state.getResourcesToAdd();

            if (doUpdate) {
                renamedFile =
                    fileUtils.createTempFile("zip", ".tmp",
                                             fileUtils.getParentFile(zipFile));
                renamedFile.deleteOnExit();

                try {
                    fileUtils.rename(zipFile, renamedFile);
                } catch (SecurityException e) {
                    throw new BuildException(
                        "Not allowed to rename old file ("
                        + zipFile.getAbsolutePath()
                        + ") to temporary file");
                } catch (IOException e) {
                    throw new BuildException(
                        "Unable to rename old file ("
                        + zipFile.getAbsolutePath()
                        + ") to temporary file");
                }
            }

            String action = doUpdate ? "Updating " : "Building ";

            log(action + archiveType + ": " + zipFile.getAbsolutePath());

            ZipOutputStream zOut = null;
            try {

                if (!skipWriting) {
                    zOut = new ZipOutputStream(zipFile);

                    zOut.setEncoding(encoding);
                    if (doCompress) {
                        zOut.setMethod(ZipOutputStream.DEFLATED);
                    } else {
                        zOut.setMethod(ZipOutputStream.STORED);
                    }
                }
                initZipOutputStream(zOut);

                // Add the explicit filesets to the archive.
                for (int i = 0; i < fss.length; i++) {
                    if (addThem[i].length != 0) {
                        addResources(fss[i], addThem[i], zOut);
                    }
                }

                if (doUpdate) {
                    addingNewFiles = false;
                    ZipFileSet oldFiles = new ZipFileSet();
                    oldFiles.setProject(getProject());
                    oldFiles.setSrc(renamedFile);

                    for (int i = 0; i < addedFiles.size(); i++) {
                        PatternSet.NameEntry ne = oldFiles.createExclude();
                        ne.setName((String) addedFiles.elementAt(i));
                    }
                    DirectoryScanner ds =
                        oldFiles.getDirectoryScanner(getProject());
                    ((ZipScanner) ds).setEncoding(encoding);

                    String[] f = ds.getIncludedFiles();
                    Resource[] r = new Resource[f.length];
                    for (int i = 0; i < f.length; i++) {
                        r[i] = ds.getResource(f[i]);
                    }

                    if (!doFilesonly) {
                        String[] d = ds.getIncludedDirectories();
                        Resource[] dr = new Resource[d.length];
                        for (int i = 0; i < d.length; i++) {
                            dr[i] = ds.getResource(d[i]);
                        }
                        Resource[] tmp = r;
                        r = new Resource[tmp.length + dr.length];
                        System.arraycopy(dr, 0, r, 0, dr.length);
                        System.arraycopy(tmp, 0, r, dr.length, tmp.length);
                    }
                    addResources(oldFiles, r, zOut);
                }
                finalizeZipOutputStream(zOut);

                // If we've been successful on an update, delete the
                // temporary file
                if (doUpdate) {
                    if (!renamedFile.delete()) {
                        log ("Warning: unable to delete temporary file "
                            + renamedFile.getName(), Project.MSG_WARN);
                    }
                }
                success = true;
            } finally {
                // Close the output stream.
                try {
                    if (zOut != null) {
                        zOut.close();
                    }
                } catch (IOException ex) {
                    // If we're in this finally clause because of an
                    // exception, we don't really care if there's an
                    // exception when closing the stream. E.g. if it
                    // throws "ZIP file must have at least one entry",
                    // because an exception happened before we added
                    // any files, then we must swallow this
                    // exception. Otherwise, the error that's reported
                    // will be the close() error, which is not the
                    // real cause of the problem.
                    if (success) {
                        throw ex;
                    }
                }
            }
        } catch (IOException ioe) {
            String msg = "Problem creating " + archiveType + ": "
                + ioe.getMessage();

            // delete a bogus ZIP file (but only if it's not the original one)
            if ((!doUpdate || renamedFile != null) && !zipFile.delete()) {
                msg += " (and the archive is probably corrupt but I could not "
                    + "delete it)";
            }

            if (doUpdate && renamedFile != null) {
                try {
                    fileUtils.rename(renamedFile, zipFile);
                } catch (IOException e) {
                    msg += " (and I couldn't rename the temporary file "
                            + renamedFile.getName() + " back)";
                }
            }

            throw new BuildException(msg, ioe, getLocation());
        } finally {
            cleanUp();
        }
    }

    /**
     * Indicates if the task is adding new files into the archive as opposed to
     * copying back unchanged files from the backup copy
     */
    protected final boolean isAddingNewFiles() {
        return addingNewFiles;
    }

    /**
     * Add the given resources.
     *
     * @param fileset may give additional information like fullpath or
     * permissions.
     * @param resources the resources to add
     * @param zOut the stream to write to
     *
     * @since Ant 1.5.2
     */
    protected final void addResources(FileSet fileset, Resource[] resources,
                                      ZipOutputStream zOut)
        throws IOException {

        String prefix = "";
        String fullpath = "";
        int dirMode = ZipFileSet.DEFAULT_DIR_MODE;
        int fileMode = ZipFileSet.DEFAULT_FILE_MODE;

        ZipFileSet zfs = null;
        if (fileset instanceof ZipFileSet) {
            zfs = (ZipFileSet) fileset;
            prefix = zfs.getPrefix(getProject());
            fullpath = zfs.getFullpath(getProject());
            dirMode = zfs.getDirMode(getProject());
            fileMode = zfs.getFileMode(getProject());
        }

        if (prefix.length() > 0 && fullpath.length() > 0) {
            throw new BuildException("Both prefix and fullpath attributes must"
                                     + " not be set on the same fileset.");
        }

        if (resources.length != 1 && fullpath.length() > 0) {
            throw new BuildException("fullpath attribute may only be specified"
                                     + " for filesets that specify a single"
                                     + " file.");
        }

        if (prefix.length() > 0) {
            if (!prefix.endsWith("/") && !prefix.endsWith("\\")) {
                prefix += "/";
            }
            addParentDirs(null, prefix, zOut, "", dirMode);
        }

        ZipFile zf = null;
        try {
            boolean dealingWithFiles = false;
            File base = null;

            if (zfs == null || zfs.getSrc(getProject()) == null) {
                dealingWithFiles = true;
                base = fileset.getDir(getProject());
            } else {
                zf = new ZipFile(zfs.getSrc(getProject()), encoding);
            }

            for (int i = 0; i < resources.length; i++) {
                String name = null;
                if (fullpath.length() > 0) {
                    name = fullpath;
                } else {
                    name = resources[i].getName();
                }
                name = name.replace(File.separatorChar, '/');

                if ("".equals(name)) {
                    continue;
                }
                if (resources[i].isDirectory() && !name.endsWith("/")) {
                    name = name + "/";
                }

                if (!doFilesonly && !dealingWithFiles
                    && resources[i].isDirectory()
                    && !zfs.hasDirModeBeenSet()) {
                    int nextToLastSlash = name.lastIndexOf("/",
                                                           name.length() - 2);
                    if (nextToLastSlash != -1) {
                        addParentDirs(base, name.substring(0,
                                                           nextToLastSlash + 1),
                                      zOut, prefix, dirMode);
                    }
                    ZipEntry ze = zf.getEntry(resources[i].getName());
                    addParentDirs(base, name, zOut, prefix, ze.getUnixMode());

                } else {
                    addParentDirs(base, name, zOut, prefix, dirMode);
                }

                if (!resources[i].isDirectory() && dealingWithFiles) {
                    File f = fileUtils.resolveFile(base,
                                                   resources[i].getName());
                    zipFile(f, zOut, prefix + name, fileMode);
                } else if (!resources[i].isDirectory()) {
                    ZipEntry ze = zf.getEntry(resources[i].getName());

                    if (ze != null) {
                        boolean oldCompress = doCompress;
                        if (keepCompression) {
                            doCompress = (ze.getMethod() == ZipEntry.DEFLATED);
                        }
                        try {
                            zipFile(zf.getInputStream(ze), zOut, prefix + name,
                                    ze.getTime(), zfs.getSrc(getProject()),
                                    zfs.hasFileModeBeenSet() ? fileMode
                                    : ze.getUnixMode());
                        } finally {
                            doCompress = oldCompress;
                        }
                    }
                }
            }
        } finally {
            if (zf != null) {
                zf.close();
            }
        }
    }

    /**
     * method for subclasses to override
     */
    protected void initZipOutputStream(ZipOutputStream zOut)
        throws IOException, BuildException {
    }

    /**
     * method for subclasses to override
     */
    protected void finalizeZipOutputStream(ZipOutputStream zOut)
        throws IOException, BuildException {
    }

    /**
     * Create an empty zip file
     *
     * @return true for historic reasons
     */
    protected boolean createEmptyZip(File zipFile) throws BuildException {
        // In this case using java.util.zip will not work
        // because it does not permit a zero-entry archive.
        // Must create it manually.
        log("Note: creating empty " + archiveType + " archive " + zipFile,
            Project.MSG_INFO);
        OutputStream os = null;
        try {
            os = new FileOutputStream(zipFile);
            // Cf. PKZIP specification.
            byte[] empty = new byte[22];
            empty[0] = 80; // P
            empty[1] = 75; // K
            empty[2] = 5;
            empty[3] = 6;
            // remainder zeros
            os.write(empty);
        } catch (IOException ioe) {
            throw new BuildException("Could not create empty ZIP archive "
                                     + "(" + ioe.getMessage() + ")", ioe,
                                     getLocation());
        } finally {
            if (os != null) {
                try {
                    os.close();
                } catch (IOException e) {
                    //ignore
                }
            }
        }
        return true;
    }

    /**
     * @since Ant 1.5.2
     */
    private synchronized ZipScanner getZipScanner() {
        if (zs == null) {
            zs = new ZipScanner();
            zs.setEncoding(encoding);
            zs.setSrc(zipFile);
        }
        return zs;
    }

    /**
     * Collect the resources that are newer than the corresponding
     * entries (or missing) in the original archive.
     *
     * <p>If we are going to recreate the archive instead of updating
     * it, all resources should be considered as new, if a single one
     * is.  Because of this, subclasses overriding this method must
     * call <code>super.getResourcesToAdd</code> and indicate with the
     * third arg if they already know that the archive is
     * out-of-date.</p>
     *
     * @param filesets The filesets to grab resources from
     * @param zipFile intended archive file (may or may not exist)
     * @param needsUpdate whether we already know that the archive is
     * out-of-date.  Subclasses overriding this method are supposed to
     * set this value correctly in their call to
     * super.getResourcesToAdd.
     * @return an array of resources to add for each fileset passed in as well
     *         as a flag that indicates whether the archive is uptodate.
     *
     * @exception BuildException if it likes
     */
    protected ArchiveState getResourcesToAdd(FileSet[] filesets,
                                             File zipFile,
                                             boolean needsUpdate)
        throws BuildException {

        Resource[][] initialResources = grabResources(filesets);
        if (isEmpty(initialResources)) {
            if (needsUpdate && doUpdate) {
                /*
                 * This is a rather hairy case.
                 *
                 * One of our subclasses knows that we need to update the
                 * archive, but at the same time, there are no resources
                 * known to us that would need to be added.  Only the
                 * subclass seems to know what's going on.
                 *
                 * This happens if <jar> detects that the manifest has changed,
                 * for example.  The manifest is not part of any resources
                 * because of our support for inline <manifest>s.
                 *
                 * If we invoke createEmptyZip like Ant 1.5.2 did,
                 * we'll loose all stuff that has been in the original
                 * archive (bugzilla report 17780).
                 */
                return new ArchiveState(true, initialResources);
            }

            if (emptyBehavior.equals("skip")) {
                if (doUpdate) {
                    log(archiveType + " archive " + zipFile
                        + " not updated because no new files were included.",
                        Project.MSG_VERBOSE);
                } else {
                    log("Warning: skipping " + archiveType + " archive "
                        + zipFile + " because no files were included.",
                        Project.MSG_WARN);
                }
            } else if (emptyBehavior.equals("fail")) {
                throw new BuildException("Cannot create " + archiveType
                                         + " archive " + zipFile
                                         + ": no files were included.",
                                         getLocation());
            } else {
                // Create.
                createEmptyZip(zipFile);
            }
            return new ArchiveState(needsUpdate, initialResources);
        }

        // initialResources is not empty

        if (!zipFile.exists()) {
            return new ArchiveState(true, initialResources);
        }

        if (needsUpdate && !doUpdate) {
            // we are recreating the archive, need all resources
            return new ArchiveState(true, initialResources);
        }

        Resource[][] newerResources = new Resource[filesets.length][];

        for (int i = 0; i < filesets.length; i++) {
            if (!(fileset instanceof ZipFileSet)
                || ((ZipFileSet) fileset).getSrc(getProject()) == null) {
                File base = filesets[i].getDir(getProject());

                for (int j = 0; j < initialResources[i].length; j++) {
                    File resourceAsFile =
                        fileUtils.resolveFile(base,
                                              initialResources[i][j].getName());
                    if (resourceAsFile.equals(zipFile)) {
                        throw new BuildException("A zip file cannot include "
                                                 + "itself", getLocation());
                    }
                }
            }
        }

        for (int i = 0; i < filesets.length; i++) {
            if (initialResources[i].length == 0) {
                newerResources[i] = new Resource[] {};
                continue;
            }

            FileNameMapper myMapper = new IdentityMapper();
            if (filesets[i] instanceof ZipFileSet) {
                ZipFileSet zfs = (ZipFileSet) filesets[i];
                if (zfs.getFullpath(getProject()) != null
                    && !zfs.getFullpath(getProject()).equals("")) {
                    // in this case all files from origin map to
                    // the fullPath attribute of the zipfileset at
                    // destination
                    MergingMapper fm = new MergingMapper();
                    fm.setTo(zfs.getFullpath(getProject()));
                    myMapper = fm;

                } else if (zfs.getPrefix(getProject()) != null
                           && !zfs.getPrefix(getProject()).equals("")) {
                    GlobPatternMapper gm = new GlobPatternMapper();
                    gm.setFrom("*");
                    String prefix = zfs.getPrefix(getProject());
                    if (!prefix.endsWith("/") && !prefix.endsWith("\\")) {
                        prefix += "/";
                    }
                    gm.setTo(prefix + "*");
                    myMapper = gm;
                }
            }

            Resource[] resources = initialResources[i];
            if (doFilesonly) {
                resources = selectFileResources(resources);
            }

            newerResources[i] =
                ResourceUtils.selectOutOfDateSources(this,
                                                     resources,
                                                     myMapper,
                                                     getZipScanner());
            needsUpdate = needsUpdate || (newerResources[i].length > 0);

            if (needsUpdate && !doUpdate) {
                // we will return initialResources anyway, no reason
                // to scan further.
                break;
            }
        }

        if (needsUpdate && !doUpdate) {
            // we are recreating the archive, need all resources
            return new ArchiveState(true, initialResources);
        }

        return new ArchiveState(needsUpdate, newerResources);
    }

    /**
     * Fetch all included and not excluded resources from the sets.
     *
     * <p>Included directories will precede included files.</p>
     *
     * @since Ant 1.5.2
     */
    protected Resource[][] grabResources(FileSet[] filesets) {
        Resource[][] result = new Resource[filesets.length][];
        for (int i = 0; i < filesets.length; i++) {
            boolean skipEmptyNames = true;
            if (filesets[i] instanceof ZipFileSet) {
                ZipFileSet zfs = (ZipFileSet) filesets[i];
                skipEmptyNames = zfs.getPrefix(getProject()).equals("")
                    && zfs.getFullpath(getProject()).equals("");
            }
            DirectoryScanner rs =
                filesets[i].getDirectoryScanner(getProject());
            if (rs instanceof ZipScanner) {
                ((ZipScanner) rs).setEncoding(encoding);
            }
            Vector resources = new Vector();
            String[] directories = rs.getIncludedDirectories();
            for (int j = 0; j < directories.length; j++) {
                if (!"".equals(directories[0]) || !skipEmptyNames) {
                    resources.addElement(rs.getResource(directories[j]));
                }
            }
            String[] files = rs.getIncludedFiles();
            for (int j = 0; j < files.length; j++) {
                if (!"".equals(files[0]) || !skipEmptyNames) {
                    resources.addElement(rs.getResource(files[j]));
                }
            }

            result[i] = new Resource[resources.size()];
            resources.copyInto(result[i]);
        }
        return result;
    }

    /**
     * @since Ant 1.5.2
     */
    protected void zipDir(File dir, ZipOutputStream zOut, String vPath,
                          int mode)
        throws IOException {
        if (addedDirs.get(vPath) != null) {
            // don't add directories we've already added.
            // no warning if we try, it is harmless in and of itself
            return;
        }

        log("adding directory " + vPath, Project.MSG_VERBOSE);
        addedDirs.put(vPath, vPath);

        if (!skipWriting) {
            ZipEntry ze = new ZipEntry (vPath);
            if (dir != null && dir.exists()) {
                // ZIPs store time with a granularity of 2 seconds, round up
                ze.setTime(dir.lastModified() + (roundUp ? 1999 : 0));
            } else {
                // ZIPs store time with a granularity of 2 seconds, round up
                ze.setTime(System.currentTimeMillis() + (roundUp ? 1999 : 0));
            }
            ze.setSize (0);
            ze.setMethod (ZipEntry.STORED);
            // This is faintly ridiculous:
            ze.setCrc (EMPTY_CRC);
            ze.setUnixMode(mode);

            zOut.putNextEntry (ze);
        }
    }

    /**
     * Adds a new entry to the archive, takes care of duplicates as well.
     *
     * @param in the stream to read data for the entry from.
     * @param zOut the stream to write to.
     * @param vPath the name this entry shall have in the archive.
     * @param lastModified last modification time for the entry.
     * @param fromArchive the original archive we are copying this
     * entry from, will be null if we are not copying from an archive.
     * @param mode the Unix permissions to set.
     *
     * @since Ant 1.5.2
     */
    protected void zipFile(InputStream in, ZipOutputStream zOut, String vPath,
                           long lastModified, File fromArchive, int mode)
        throws IOException {
        if (entries.contains(vPath)) {

            if (duplicate.equals("preserve")) {
                log(vPath + " already added, skipping", Project.MSG_INFO);
                return;
            } else if (duplicate.equals("fail")) {
                throw new BuildException("Duplicate file " + vPath
                                         + " was found and the duplicate "
                                         + "attribute is 'fail'.");
            } else {
                // duplicate equal to add, so we continue
                log("duplicate file " + vPath
                    + " found, adding.", Project.MSG_VERBOSE);
            }
        } else {
            log("adding entry " + vPath, Project.MSG_VERBOSE);
        }

        entries.put(vPath, vPath);

        if (!skipWriting) {
            ZipEntry ze = new ZipEntry(vPath);
            ze.setTime(lastModified);
            ze.setMethod(doCompress ? ZipEntry.DEFLATED : ZipEntry.STORED);

            /*
            * ZipOutputStream.putNextEntry expects the ZipEntry to
            * know its size and the CRC sum before you start writing
            * the data when using STORED mode - unless it is seekable.
            *
            * This forces us to process the data twice.
            */
            if (!zOut.isSeekable() && !doCompress) {
                long size = 0;
                CRC32 cal = new CRC32();
                if (!in.markSupported()) {
                    // Store data into a byte[]
                    ByteArrayOutputStream bos = new ByteArrayOutputStream();

                    byte[] buffer = new byte[8 * 1024];
                    int count = 0;
                    do {
                        size += count;
                        cal.update(buffer, 0, count);
                        bos.write(buffer, 0, count);
                        count = in.read(buffer, 0, buffer.length);
                    } while (count != -1);
                    in = new ByteArrayInputStream(bos.toByteArray());

                } else {
                    in.mark(Integer.MAX_VALUE);
                    byte[] buffer = new byte[8 * 1024];
                    int count = 0;
                    do {
                        size += count;
                        cal.update(buffer, 0, count);
                        count = in.read(buffer, 0, buffer.length);
                    } while (count != -1);
                    in.reset();
                }
                ze.setSize(size);
                ze.setCrc(cal.getValue());
            }

            ze.setUnixMode(mode);
            zOut.putNextEntry(ze);

            byte[] buffer = new byte[8 * 1024];
            int count = 0;
            do {
                if (count != 0) {
                    zOut.write(buffer, 0, count);
                }
                count = in.read(buffer, 0, buffer.length);
            } while (count != -1);
        }
        addedFiles.addElement(vPath);
    }

    /**
     * Method that gets called when adding from java.io.File instances.
     *
     * <p>This implementation delegates to the six-arg version.</p>
     *
     * @param file the file to add to the archive
     * @param zOut the stream to write to
     * @param vPath the name this entry shall have in the archive
     * @param mode the Unix permissions to set.
     *
     * @since Ant 1.5.2
     */
    protected void zipFile(File file, ZipOutputStream zOut, String vPath,
                           int mode)
        throws IOException {
        if (file.equals(zipFile)) {
            throw new BuildException("A zip file cannot include itself",
                                     getLocation());
        }

        FileInputStream fIn = new FileInputStream(file);
        try {
            // ZIPs store time with a granularity of 2 seconds, round up
            zipFile(fIn, zOut, vPath, 
                    file.lastModified() + (roundUp ? 1999 : 0),
                    null, mode);
        } finally {
            fIn.close();
        }
    }

    /**
     * Ensure all parent dirs of a given entry have been added.
     *
     * @since Ant 1.5.2
     */
    protected final void addParentDirs(File baseDir, String entry,
                                       ZipOutputStream zOut, String prefix,
                                       int dirMode)
        throws IOException {
        if (!doFilesonly) {
            Stack directories = new Stack();
            int slashPos = entry.length();

            while ((slashPos = entry.lastIndexOf('/', slashPos - 1)) != -1) {
                String dir = entry.substring(0, slashPos + 1);
                if (addedDirs.get(prefix + dir) != null) {
                    break;
                }
                directories.push(dir);
            }

            while (!directories.isEmpty()) {
                String dir = (String) directories.pop();
                File f = null;
                if (baseDir != null) {
                    f = new File(baseDir, dir);
                } else {
                    f = new File(dir);
                }
                zipDir(f, zOut, prefix + dir, dirMode);
            }
        }
    }

    /**
     * Do any clean up necessary to allow this instance to be used again.
     *
     * <p>When we get here, the Zip file has been closed and all we
     * need to do is to reset some globals.</p>
     *
     * <p>This method will only reset globals that have been changed
     * during execute(), it will not alter the attributes or nested
     * child elements.  If you want to reset the instance so that you
     * can later zip a completely different set of files, you must use
     * the reset method.</p>
     *
     * @see #reset
     */
    protected void cleanUp() {
        addedDirs.clear();
        addedFiles.removeAllElements();
        entries.clear();
        addingNewFiles = false;
        doUpdate = savedDoUpdate;
        Enumeration e = filesetsFromGroupfilesets.elements();
        while (e.hasMoreElements()) {
            ZipFileSet zf = (ZipFileSet) e.nextElement();
            filesets.removeElement(zf);
        }
        filesetsFromGroupfilesets.removeAllElements();
    }

    /**
     * Makes this instance reset all attributes to their default
     * values and forget all children.
     *
     * @since Ant 1.5
     *
     * @see #cleanUp
     */
    public void reset() {
        filesets.removeAllElements();
        zipFile = null;
        baseDir = null;
        groupfilesets.removeAllElements();
        duplicate = "add";
        archiveType = "zip";
        doCompress = true;
        emptyBehavior = "skip";
        doUpdate = false;
        doFilesonly = false;
        encoding = null;
    }

    /**
     * @return true if all individual arrays are empty
     *
     * @since Ant 1.5.2
     */
    protected static final boolean isEmpty(Resource[][] r) {
        for (int i = 0; i < r.length; i++) {
            if (r[i].length > 0) {
                return false;
            }
        }
        return true;
    }

    /**
     * Drops all non-file resources from the given array.
     *
     * @since Ant 1.6
     */
    protected Resource[] selectFileResources(Resource[] orig) {
        if (orig.length == 0) {
            return orig;
        }

        Vector v = new Vector(orig.length);
        for (int i = 0; i < orig.length; i++) {
            if (!orig[i].isDirectory()) {
                v.addElement(orig[i]);
            } else {
                log("Ignoring directory " + orig[i].getName()
                    + " as only files will be added.", Project.MSG_VERBOSE);
            }
        }

        if (v.size() != orig.length) {
            Resource[] r = new Resource[v.size()];
            v.copyInto(r);
            return r;
        }
        return orig;
    }

    /**
     * Possible behaviors when a duplicate file is added:
     * "add", "preserve" or "fail"
     */
    public static class Duplicate extends EnumeratedAttribute {
        public String[] getValues() {
            return new String[] {"add", "preserve", "fail"};
        }
    }

    /**
     * Holds the up-to-date status and the out-of-date resources of
     * the original archive.
     *
     * @since Ant 1.5.3
     */
    public static class ArchiveState {
        private boolean outOfDate;
        private Resource[][] resourcesToAdd;

        ArchiveState(boolean state, Resource[][] r) {
            outOfDate = state;
            resourcesToAdd = r;
        }

        public boolean isOutOfDate() {
            return outOfDate;
        }

        public Resource[][] getResourcesToAdd() {
            return resourcesToAdd;
        }
    }
}