/*
 *  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
 *
 *      https://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.util;

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.net.HttpURLConnection;
import java.net.JarURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.channels.Channel;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
import java.util.Optional;
import java.util.Random;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.jar.JarFile;
import java.util.stream.Collectors;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.PathTokenizer;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.launch.Locator;
import org.apache.tools.ant.taskdefs.condition.Os;
import org.apache.tools.ant.types.FilterChain;
import org.apache.tools.ant.types.FilterSetCollection;
import org.apache.tools.ant.types.resources.FileResource;

This class also encapsulates methods which allow Files to be
referred to using abstract path names which are translated to native
system file paths at runtime as well as copying files or setting
their last modification time.
/**
 * This class also encapsulates methods which allow Files to be
 * referred to using abstract path names which are translated to native
 * system file paths at runtime as well as copying files or setting
 * their last modification time.
 *
 */
public class FileUtils {
    private static final int DELETE_RETRY_SLEEP_MILLIS = 10;
    private static final int EXPAND_SPACE = 50;
    private static final FileUtils PRIMARY_INSTANCE = new FileUtils();

    //get some non-crypto-grade randomness from various places.
    private static Random rand = new Random(System.currentTimeMillis()
            + Runtime.getRuntime().freeMemory());

    private static final boolean ON_NETWARE = Os.isFamily("netware");
    private static final boolean ON_DOS = Os.isFamily("dos");
    private static final boolean ON_WIN9X = Os.isFamily("win9x");
    private static final boolean ON_WINDOWS = Os.isFamily("windows");

    static final int BUF_SIZE = 8192;


    
The granularity of timestamps under FAT.
/**
     * The granularity of timestamps under FAT.
     */
    public static final long FAT_FILE_TIMESTAMP_GRANULARITY = 2000;

    
The granularity of timestamps under Unix.
/**
     * The granularity of timestamps under Unix.
     */
    public static final long UNIX_FILE_TIMESTAMP_GRANULARITY = 1000;

    
The granularity of timestamps under the NT File System.
NTFS has a granularity of 100 nanoseconds, which is less
than 1 millisecond, so we round this up to 1 millisecond.
/**
     * The granularity of timestamps under the NT File System.
     * NTFS has a granularity of 100 nanoseconds, which is less
     * than 1 millisecond, so we round this up to 1 millisecond.
     */
    public static final long NTFS_FILE_TIMESTAMP_GRANULARITY = 1;

    
A one item cache for fromUri.
fromUri is called for each element when parsing ant build
files. It is a costly operation. This just caches the result
of the last call.
/**
     * A one item cache for fromUri.
     * fromUri is called for each element when parsing ant build
     * files. It is a costly operation. This just caches the result
     * of the last call.
     */
    private Object cacheFromUriLock = new Object();
    private String cacheFromUriRequest = null;
    private String cacheFromUriResponse = null;

    
Factory method.
Returns:
a new instance of FileUtils.
Deprecated:
since 1.7.
            Use getFileUtils instead,
FileUtils do not have state./**
     * Factory method.
     *
     * @return a new instance of FileUtils.
     * @deprecated since 1.7.
     *             Use getFileUtils instead,
     * FileUtils do not have state.
     */
    @Deprecated
    public static FileUtils newFileUtils() {
        return new FileUtils();
    }

    
Method to retrieve The FileUtils, which is shared by all users of this
method.
Returns:
an instance of FileUtils.
Since:
Ant 1.6.3/**
     * Method to retrieve The FileUtils, which is shared by all users of this
     * method.
     * @return an instance of FileUtils.
     * @since Ant 1.6.3
     */
    public static FileUtils getFileUtils() {
        return PRIMARY_INSTANCE;
    }

    
Empty constructor.
/**
     * Empty constructor.
     */
    protected FileUtils() {
    }

    
Get the URL for a file taking into account # characters.
Params:
file – the file whose URL representation is required.
Throws:
MalformedURLException – if the URL representation cannot be
     formed.
Returns:
The FileURL value./**
     * Get the URL for a file taking into account # characters.
     *
     * @param file the file whose URL representation is required.
     * @return The FileURL value.
     * @throws MalformedURLException if the URL representation cannot be
     *      formed.
     */
    public URL getFileURL(File file) throws MalformedURLException {
        return new URL(file.toURI().toASCIIString());
    }

    
Convenience method to copy a file from a source to a destination.
No filtering is performed.
Params:
sourceFile – Name of file to copy from.
                  Must not be null.
destFile – Name of file to copy to.
                Must not be null.
Throws:
IOException – if the copying fails./**
     * Convenience method to copy a file from a source to a destination.
     * No filtering is performed.
     *
     * @param sourceFile Name of file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile Name of file to copy to.
     *                 Must not be <code>null</code>.
     *
     * @throws IOException if the copying fails.
     */
    public void copyFile(String sourceFile, String destFile) throws IOException {
        copyFile(new File(sourceFile), new File(destFile), null, false, false);
    }

    
Convenience method to copy a file from a source to a destination
specifying if token filtering must be used.
Params:
sourceFile – Name of file to copy from.
                  Must not be null.
destFile – Name of file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
Throws:
IOException – if the copying fails./**
     * Convenience method to copy a file from a source to a destination
     * specifying if token filtering must be used.
     *
     * @param sourceFile Name of file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile Name of file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     *
     * @throws IOException if the copying fails.
     */
    public void copyFile(String sourceFile, String destFile, FilterSetCollection filters)
            throws IOException {
        copyFile(new File(sourceFile), new File(destFile), filters, false, false);
    }

    
Convenience method to copy a file from a source to a destination specifying if token
filtering must be used and if source files may overwrite newer destination files.
Params:
sourceFile – Name of file to copy from. Must not be null.
destFile – Name of file to copy to. Must not be null.
filters – the collection of filters to apply to this copy.
overwrite – Whether or not the destination file should be overwritten if it already
           exists.
Throws:
IOException – if the copying fails./**
     * Convenience method to copy a file from a source to a destination specifying if token
     * filtering must be used and if source files may overwrite newer destination files.
     *
     * @param sourceFile Name of file to copy from. Must not be <code>null</code>.
     * @param destFile Name of file to copy to. Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param overwrite Whether or not the destination file should be overwritten if it already
     *            exists.
     *
     * @throws IOException if the copying fails.
     */
    public void copyFile(String sourceFile, String destFile, FilterSetCollection filters,
                         boolean overwrite) throws IOException {
        copyFile(new File(sourceFile), new File(destFile), filters, overwrite, false);
    }

    
Convenience method to copy a file from a source to a destination
specifying if token
filtering must be used, if source files may overwrite newer destination
files and the last
modified time of destFile file should be made equal to
the last modified time
of sourceFile.
Params:
sourceFile – Name of file to copy from. Must not be null.
destFile – Name of file to copy to. Must not be null.
filters – the collection of filters to apply to this copy.
overwrite – Whether or not the destination file should be
           overwritten if it already exists.
preserveLastModified – Whether or not the last modified time of
           the resulting file
           should be set to that of the source file.
Throws:
IOException – if the copying fails./**
     * Convenience method to copy a file from a source to a destination
     * specifying if token
     * filtering must be used, if source files may overwrite newer destination
     * files and the last
     * modified time of <code>destFile</code> file should be made equal to
     * the last modified time
     * of <code>sourceFile</code>.
     *
     * @param sourceFile Name of file to copy from. Must not be <code>null</code>.
     * @param destFile Name of file to copy to. Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param overwrite Whether or not the destination file should be
     *            overwritten if it already exists.
     * @param preserveLastModified Whether or not the last modified time of
     *            the resulting file
     *            should be set to that of the source file.
     *
     * @throws IOException if the copying fails.
     */
    public void copyFile(String sourceFile, String destFile,
                         FilterSetCollection filters,
                         boolean overwrite, boolean preserveLastModified)
        throws IOException {
        copyFile(new File(sourceFile), new File(destFile), filters, overwrite,
                 preserveLastModified);
    }

    
Convenience method to copy a file from a source to a destination specifying if token
filtering must be used, if source files may overwrite newer destination files and the last
modified time of destFile file should be made equal to the last modified time
of sourceFile.
Params:
sourceFile – Name of file to copy from. Must not be null.
destFile – Name of file to copy to. Must not be null.
filters – the collection of filters to apply to this copy.
overwrite – Whether or not the destination file should be overwritten if it already
           exists.
preserveLastModified – Whether or not the last modified time of the resulting file
           should be set to that of the source file.
encoding – the encoding used to read and write the files.
Throws:
IOException – if the copying fails.
Since:
Ant 1.5/**
     * Convenience method to copy a file from a source to a destination specifying if token
     * filtering must be used, if source files may overwrite newer destination files and the last
     * modified time of <code>destFile</code> file should be made equal to the last modified time
     * of <code>sourceFile</code>.
     *
     * @param sourceFile Name of file to copy from. Must not be <code>null</code>.
     * @param destFile Name of file to copy to. Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param overwrite Whether or not the destination file should be overwritten if it already
     *            exists.
     * @param preserveLastModified Whether or not the last modified time of the resulting file
     *            should be set to that of the source file.
     * @param encoding the encoding used to read and write the files.
     *
     * @throws IOException if the copying fails.
     *
     * @since Ant 1.5
     */
    public void copyFile(String sourceFile, String destFile,
                         FilterSetCollection filters, boolean overwrite,
                         boolean preserveLastModified, String encoding) throws IOException {
        copyFile(new File(sourceFile), new File(destFile), filters,
                 overwrite, preserveLastModified, encoding);
    }

    // CheckStyle:ParameterNumberCheck OFF - bc
    
Convenience method to copy a file from a source to a
destination specifying if token filtering must be used, if
filter chains must be used, if source files may overwrite
newer destination files and the last modified time of
destFile file should be made equal
to the last modified time of sourceFile.
Params:
sourceFile – Name of file to copy from.
                  Must not be null.
destFile – Name of file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
filterChains – filterChains to apply during the copy.
overwrite – Whether or not the destination file should be
                 overwritten if it already exists.
preserveLastModified – Whether or not the last modified time of
                            the resulting file should be set to that
                            of the source file.
encoding – the encoding used to read and write the files.
project – the project instance.
Throws:
IOException – if the copying fails.
Since:
Ant 1.5/**
     * Convenience method to copy a file from a source to a
     * destination specifying if token filtering must be used, if
     * filter chains must be used, if source files may overwrite
     * newer destination files and the last modified time of
     * <code>destFile</code> file should be made equal
     * to the last modified time of <code>sourceFile</code>.
     *
     * @param sourceFile Name of file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile Name of file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param filterChains filterChains to apply during the copy.
     * @param overwrite Whether or not the destination file should be
     *                  overwritten if it already exists.
     * @param preserveLastModified Whether or not the last modified time of
     *                             the resulting file should be set to that
     *                             of the source file.
     * @param encoding the encoding used to read and write the files.
     * @param project the project instance.
     *
     * @throws IOException if the copying fails.
     *
     * @since Ant 1.5
     */
    public void copyFile(String sourceFile, String destFile,
                         FilterSetCollection filters, Vector<FilterChain> filterChains,
                         boolean overwrite, boolean preserveLastModified,
                         String encoding, Project project) throws IOException {
        copyFile(new File(sourceFile), new File(destFile), filters, filterChains, overwrite,
                preserveLastModified, encoding, project);
    }

    
Convenience method to copy a file from a source to a destination specifying if token
filtering must be used, if filter chains must be used, if source files may overwrite newer
destination files and the last modified time of destFile file should be made
equal to the last modified time of sourceFile.
Params:
sourceFile – Name of file to copy from. Must not be null.
destFile – Name of file to copy to. Must not be null.
filters – the collection of filters to apply to this copy.
filterChains – filterChains to apply during the copy.
overwrite – Whether or not the destination file should be overwritten if it already
           exists.
preserveLastModified – Whether or not the last modified time of the resulting file
           should be set to that of the source file.
inputEncoding – the encoding used to read the files.
outputEncoding – the encoding used to write the files.
project – the project instance.
Throws:
IOException – if the copying fails.
Since:
Ant 1.6/**
     * Convenience method to copy a file from a source to a destination specifying if token
     * filtering must be used, if filter chains must be used, if source files may overwrite newer
     * destination files and the last modified time of <code>destFile</code> file should be made
     * equal to the last modified time of <code>sourceFile</code>.
     *
     * @param sourceFile Name of file to copy from. Must not be <code>null</code>.
     * @param destFile Name of file to copy to. Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param filterChains filterChains to apply during the copy.
     * @param overwrite Whether or not the destination file should be overwritten if it already
     *            exists.
     * @param preserveLastModified Whether or not the last modified time of the resulting file
     *            should be set to that of the source file.
     * @param inputEncoding the encoding used to read the files.
     * @param outputEncoding the encoding used to write the files.
     * @param project the project instance.
     *
     * @throws IOException if the copying fails.
     *
     * @since Ant 1.6
     */
    public void copyFile(String sourceFile, String destFile,
                         FilterSetCollection filters, Vector<FilterChain> filterChains,
                         boolean overwrite, boolean preserveLastModified,
                         String inputEncoding, String outputEncoding,
                         Project project) throws IOException {
        copyFile(new File(sourceFile), new File(destFile), filters, filterChains, overwrite,
                preserveLastModified, inputEncoding, outputEncoding, project);
    }

    
Convenience method to copy a file from a source to a destination. No filtering is performed.
Params:
sourceFile – the file to copy from. Must not be null.
destFile – the file to copy to. Must not be null.
Throws:
IOException – if the copying fails./**
     * Convenience method to copy a file from a source to a destination. No filtering is performed.
     *
     * @param sourceFile the file to copy from. Must not be <code>null</code>.
     * @param destFile the file to copy to. Must not be <code>null</code>.
     *
     * @throws IOException if the copying fails.
     */
    public void copyFile(File sourceFile, File destFile) throws IOException {
        copyFile(sourceFile, destFile, null, false, false);
    }

    
Convenience method to copy a file from a source to a destination
specifying if token filtering must be used.
Params:
sourceFile – the file to copy from.
                  Must not be null.
destFile – the file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
Throws:
IOException – if the copying fails./**
     * Convenience method to copy a file from a source to a destination
     * specifying if token filtering must be used.
     *
     * @param sourceFile the file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile the file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     *
     * @throws IOException if the copying fails.
     */
    public void copyFile(File sourceFile, File destFile, FilterSetCollection filters)
            throws IOException {
        copyFile(sourceFile, destFile, filters, false, false);
    }

    
Convenience method to copy a file from a source to a
destination specifying if token filtering must be used and if
source files may overwrite newer destination files.
Params:
sourceFile – the file to copy from.
                  Must not be null.
destFile – the file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
overwrite – Whether or not the destination file should be
                 overwritten if it already exists.
Throws:
IOException – if the copying fails./**
     * Convenience method to copy a file from a source to a
     * destination specifying if token filtering must be used and if
     * source files may overwrite newer destination files.
     *
     * @param sourceFile the file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile the file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param overwrite Whether or not the destination file should be
     *                  overwritten if it already exists.
     *
     * @throws IOException if the copying fails.
     */
    public void copyFile(File sourceFile, File destFile, FilterSetCollection filters,
                         boolean overwrite) throws IOException {
        copyFile(sourceFile, destFile, filters, overwrite, false);
    }

    
Convenience method to copy a file from a source to a
destination specifying if token filtering must be used, if
source files may overwrite newer destination files and the
last modified time of destFile file should be made equal
to the last modified time of sourceFile.
Params:
sourceFile – the file to copy from.
                  Must not be null.
destFile – the file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
overwrite – Whether or not the destination file should be
                 overwritten if it already exists.
preserveLastModified – Whether or not the last modified time of
                            the resulting file should be set to that
                            of the source file.
Throws:
IOException – if the copying fails./**
     * Convenience method to copy a file from a source to a
     * destination specifying if token filtering must be used, if
     * source files may overwrite newer destination files and the
     * last modified time of <code>destFile</code> file should be made equal
     * to the last modified time of <code>sourceFile</code>.
     *
     * @param sourceFile the file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile the file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param overwrite Whether or not the destination file should be
     *                  overwritten if it already exists.
     * @param preserveLastModified Whether or not the last modified time of
     *                             the resulting file should be set to that
     *                             of the source file.
     *
     * @throws IOException if the copying fails.
     */
    public void copyFile(File sourceFile, File destFile, FilterSetCollection filters,
                         boolean overwrite, boolean preserveLastModified) throws IOException {
        copyFile(sourceFile, destFile, filters, overwrite, preserveLastModified, null);
    }

    
Convenience method to copy a file from a source to a destination specifying if token
filtering must be used, if source files may overwrite newer destination files, the last
modified time of destFile file should be made equal to the last modified time
of sourceFile and which character encoding to assume.
Params:
sourceFile – the file to copy from. Must not be null.
destFile – the file to copy to. Must not be null.
filters – the collection of filters to apply to this copy.
overwrite – Whether or not the destination file should be overwritten if it already
           exists.
preserveLastModified – Whether or not the last modified time of the resulting file
           should be set to that of the source file.
encoding – the encoding used to read and write the files.
Throws:
IOException – if the copying fails.
Since:
Ant 1.5/**
     * Convenience method to copy a file from a source to a destination specifying if token
     * filtering must be used, if source files may overwrite newer destination files, the last
     * modified time of <code>destFile</code> file should be made equal to the last modified time
     * of <code>sourceFile</code> and which character encoding to assume.
     *
     * @param sourceFile the file to copy from. Must not be <code>null</code>.
     * @param destFile the file to copy to. Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param overwrite Whether or not the destination file should be overwritten if it already
     *            exists.
     * @param preserveLastModified Whether or not the last modified time of the resulting file
     *            should be set to that of the source file.
     * @param encoding the encoding used to read and write the files.
     *
     * @throws IOException if the copying fails.
     *
     * @since Ant 1.5
     */
    public void copyFile(File sourceFile, File destFile,
                         FilterSetCollection filters, boolean overwrite,
                         boolean preserveLastModified, String encoding) throws IOException {
        copyFile(sourceFile, destFile, filters, null, overwrite,
                 preserveLastModified, encoding, null);
    }

    
Convenience method to copy a file from a source to a
destination specifying if token filtering must be used, if
filter chains must be used, if source files may overwrite
newer destination files and the last modified time of
destFile file should be made equal
to the last modified time of sourceFile.
Params:
sourceFile – the file to copy from.
                  Must not be null.
destFile – the file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
filterChains – filterChains to apply during the copy.
overwrite – Whether or not the destination file should be
                 overwritten if it already exists.
preserveLastModified – Whether or not the last modified time of
                            the resulting file should be set to that
                            of the source file.
encoding – the encoding used to read and write the files.
project – the project instance.
Throws:
IOException – if the copying fails.
Since:
Ant 1.5/**
     * Convenience method to copy a file from a source to a
     * destination specifying if token filtering must be used, if
     * filter chains must be used, if source files may overwrite
     * newer destination files and the last modified time of
     * <code>destFile</code> file should be made equal
     * to the last modified time of <code>sourceFile</code>.
     *
     * @param sourceFile the file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile the file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param filterChains filterChains to apply during the copy.
     * @param overwrite Whether or not the destination file should be
     *                  overwritten if it already exists.
     * @param preserveLastModified Whether or not the last modified time of
     *                             the resulting file should be set to that
     *                             of the source file.
     * @param encoding the encoding used to read and write the files.
     * @param project the project instance.
     *
     * @throws IOException if the copying fails.
     *
     * @since Ant 1.5
     */
    public void copyFile(File sourceFile, File destFile,
                         FilterSetCollection filters, Vector<FilterChain> filterChains,
                         boolean overwrite, boolean preserveLastModified,
                         String encoding, Project project) throws IOException {
        copyFile(sourceFile, destFile, filters, filterChains,
                 overwrite, preserveLastModified, encoding, encoding, project);
    }

    
Convenience method to copy a file from a source to a
destination specifying if token filtering must be used, if
filter chains must be used, if source files may overwrite
newer destination files and the last modified time of
destFile file should be made equal
to the last modified time of sourceFile.
Params:
sourceFile – the file to copy from.
                  Must not be null.
destFile – the file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
filterChains – filterChains to apply during the copy.
overwrite – Whether or not the destination file should be
                 overwritten if it already exists.
preserveLastModified – Whether or not the last modified time of
                            the resulting file should be set to that
                            of the source file.
inputEncoding – the encoding used to read the files.
outputEncoding – the encoding used to write the files.
project – the project instance.
Throws:
IOException – if the copying fails.
Since:
Ant 1.6/**
     * Convenience method to copy a file from a source to a
     * destination specifying if token filtering must be used, if
     * filter chains must be used, if source files may overwrite
     * newer destination files and the last modified time of
     * <code>destFile</code> file should be made equal
     * to the last modified time of <code>sourceFile</code>.
     *
     * @param sourceFile the file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile the file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param filterChains filterChains to apply during the copy.
     * @param overwrite Whether or not the destination file should be
     *                  overwritten if it already exists.
     * @param preserveLastModified Whether or not the last modified time of
     *                             the resulting file should be set to that
     *                             of the source file.
     * @param inputEncoding the encoding used to read the files.
     * @param outputEncoding the encoding used to write the files.
     * @param project the project instance.
     *
     *
     * @throws IOException if the copying fails.
     *
     * @since Ant 1.6
     */
    public void copyFile(File sourceFile, File destFile,
            FilterSetCollection filters, Vector<FilterChain> filterChains,
            boolean overwrite, boolean preserveLastModified,
            String inputEncoding, String outputEncoding,
            Project project) throws IOException {
        copyFile(sourceFile, destFile, filters, filterChains, overwrite, preserveLastModified,
                false, inputEncoding, outputEncoding, project);
    }

    
Convenience method to copy a file from a source to a
destination specifying if token filtering must be used, if
filter chains must be used, if source files may overwrite
newer destination files and the last modified time of
destFile file should be made equal
to the last modified time of sourceFile.
Params:
sourceFile – the file to copy from.
                  Must not be null.
destFile – the file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
filterChains – filterChains to apply during the copy.
overwrite – Whether or not the destination file should be
                 overwritten if it already exists.
preserveLastModified – Whether or not the last modified time of
                            the resulting file should be set to that
                            of the source file.
append – whether to append to the destination file.
inputEncoding – the encoding used to read the files.
outputEncoding – the encoding used to write the files.
project – the project instance.
Throws:
IOException – if the copying fails.
Since:
Ant 1.8/**
     * Convenience method to copy a file from a source to a
     * destination specifying if token filtering must be used, if
     * filter chains must be used, if source files may overwrite
     * newer destination files and the last modified time of
     * <code>destFile</code> file should be made equal
     * to the last modified time of <code>sourceFile</code>.
     *
     * @param sourceFile the file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile the file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param filterChains filterChains to apply during the copy.
     * @param overwrite Whether or not the destination file should be
     *                  overwritten if it already exists.
     * @param preserveLastModified Whether or not the last modified time of
     *                             the resulting file should be set to that
     *                             of the source file.
     * @param append whether to append to the destination file.
     * @param inputEncoding the encoding used to read the files.
     * @param outputEncoding the encoding used to write the files.
     * @param project the project instance.
     *
     *
     * @throws IOException if the copying fails.
     *
     * @since Ant 1.8
     */
    public void copyFile(File sourceFile, File destFile,
                         FilterSetCollection filters, Vector<FilterChain> filterChains,
                         boolean overwrite, boolean preserveLastModified,
                         boolean append,
                         String inputEncoding, String outputEncoding,
                         Project project) throws IOException {
        copyFile(sourceFile, destFile, filters, filterChains, overwrite,
                 preserveLastModified, append, inputEncoding, outputEncoding,
                 project, /* force: */ false);
    }

    
Convenience method to copy a file from a source to a
destination specifying if token filtering must be used, if
filter chains must be used, if source files may overwrite
newer destination files and the last modified time of
destFile file should be made equal
to the last modified time of sourceFile.
Params:
sourceFile – the file to copy from.
                  Must not be null.
destFile – the file to copy to.
                Must not be null.
filters – the collection of filters to apply to this copy.
filterChains – filterChains to apply during the copy.
overwrite – Whether or not the destination file should be
                 overwritten if it already exists.
preserveLastModified – Whether or not the last modified time of
                            the resulting file should be set to that
                            of the source file.
append – whether to append to the destination file.
inputEncoding – the encoding used to read the files.
outputEncoding – the encoding used to write the files.
project – the project instance.
force – whether to overwrite read-only destination files.
Throws:
IOException – if the copying fails.
Since:
Ant 1.8.2/**
     * Convenience method to copy a file from a source to a
     * destination specifying if token filtering must be used, if
     * filter chains must be used, if source files may overwrite
     * newer destination files and the last modified time of
     * <code>destFile</code> file should be made equal
     * to the last modified time of <code>sourceFile</code>.
     *
     * @param sourceFile the file to copy from.
     *                   Must not be <code>null</code>.
     * @param destFile the file to copy to.
     *                 Must not be <code>null</code>.
     * @param filters the collection of filters to apply to this copy.
     * @param filterChains filterChains to apply during the copy.
     * @param overwrite Whether or not the destination file should be
     *                  overwritten if it already exists.
     * @param preserveLastModified Whether or not the last modified time of
     *                             the resulting file should be set to that
     *                             of the source file.
     * @param append whether to append to the destination file.
     * @param inputEncoding the encoding used to read the files.
     * @param outputEncoding the encoding used to write the files.
     * @param project the project instance.
     * @param force whether to overwrite read-only destination files.
     *
     * @throws IOException if the copying fails.
     *
     * @since Ant 1.8.2
     */
    public void copyFile(File sourceFile, File destFile,
                         FilterSetCollection filters, Vector<FilterChain> filterChains,
                         boolean overwrite, boolean preserveLastModified,
                         boolean append,
                         String inputEncoding, String outputEncoding,
                         Project project, boolean force) throws IOException {
        ResourceUtils.copyResource(new FileResource(sourceFile),
                                   new FileResource(destFile),
                                   filters, filterChains, overwrite,
                                   preserveLastModified, append, inputEncoding,
                                   outputEncoding, project, force);
    }

    // CheckStyle:ParameterNumberCheck ON

    
Calls File.setLastModified(long time). Originally written to
to dynamically bind to that call on Java1.2+.
Params:
file – the file whose modified time is to be set
time – the time to which the last modified time is to be set.
            if this is -1, the current time is used./**
     * Calls File.setLastModified(long time). Originally written to
     * to dynamically bind to that call on Java1.2+.
     *
     * @param file the file whose modified time is to be set
     * @param time the time to which the last modified time is to be set.
     *             if this is -1, the current time is used.
     */
    public void setFileLastModified(File file, long time) {
        ResourceUtils.setLastModified(new FileResource(file), time);
    }

    
Interpret the filename as a file relative to the given file
unless the filename already represents an absolute filename.
Differs from new File(file, filename) in that
the resulting File's path will always be a normalized,
absolute pathname.  Also, if it is determined that
filename is context-relative, file
will be discarded and the reference will be resolved using
available context/state information about the filesystem.
Params:
file – the "reference" file for relative paths. This
instance must be an absolute file and must not contain
"./" or "../" sequences (same for \ instead
of /).  If it is null, this call is equivalent to
new java.io.File(filename).getAbsoluteFile().
filename – a file name.
Throws:
NullPointerException – if filename is null.
Returns:
an absolute file./**
     * Interpret the filename as a file relative to the given file
     * unless the filename already represents an absolute filename.
     * Differs from <code>new File(file, filename)</code> in that
     * the resulting File's path will always be a normalized,
     * absolute pathname.  Also, if it is determined that
     * <code>filename</code> is context-relative, <code>file</code>
     * will be discarded and the reference will be resolved using
     * available context/state information about the filesystem.
     *
     * @param file the "reference" file for relative paths. This
     * instance must be an absolute file and must not contain
     * &quot;./&quot; or &quot;../&quot; sequences (same for \ instead
     * of /).  If it is null, this call is equivalent to
     * <code>new java.io.File(filename).getAbsoluteFile()</code>.
     *
     * @param filename a file name.
     *
     * @return an absolute file.
     * @throws java.lang.NullPointerException if filename is null.
     */
    public File resolveFile(File file, String filename) {
        if (!isAbsolutePath(filename)) {
            char sep = File.separatorChar;
            filename = filename.replace('/', sep).replace('\\', sep);
            if (isContextRelativePath(filename)) {
                file = null;
                // on cygwin, our current directory can be a UNC;
                // assume user.dir is absolute or all hell breaks loose...
                String udir = System.getProperty("user.dir");
                if (filename.charAt(0) == sep && udir.charAt(0) == sep) {
                    filename = dissect(udir)[0] + filename.substring(1);
                }
            }
            filename = new File(file, filename).getAbsolutePath();
        }
        return normalize(filename);
    }

    
On DOS and NetWare, the evaluation of certain file
specifications is context-dependent.  These are filenames
beginning with a single separator (relative to current root directory)
and filenames with a drive specification and no intervening separator
(relative to current directory of the specified root).
Params:
filename – the filename to evaluate.
Throws:
NullPointerException – if filename is null.
Returns:
true if the filename is relative to system context.
Since:
Ant 1.7/**
     * On DOS and NetWare, the evaluation of certain file
     * specifications is context-dependent.  These are filenames
     * beginning with a single separator (relative to current root directory)
     * and filenames with a drive specification and no intervening separator
     * (relative to current directory of the specified root).
     * @param filename the filename to evaluate.
     * @return true if the filename is relative to system context.
     * @throws java.lang.NullPointerException if filename is null.
     * @since Ant 1.7
     */
    public static boolean isContextRelativePath(String filename) {
        if (!(ON_DOS || ON_NETWARE) || filename.isEmpty()) {
            return false;
        }
        char sep = File.separatorChar;
        filename = filename.replace('/', sep).replace('\\', sep);
        char c = filename.charAt(0);
        int len = filename.length();
        return (c == sep && (len == 1 || filename.charAt(1) != sep))
                || (Character.isLetter(c) && len > 1
                && filename.charAt(1) == ':'
                && (len == 2 || filename.charAt(2) != sep));
    }

    
Verifies that the specified filename represents an absolute path.
Differs from new java.io.File("filename").isAbsolute() in that a path
beginning with a double file separator--signifying a Windows UNC--must
at minimum match "\\a\b" to be considered an absolute path.
Params:
filename – the filename to be checked.
Throws:
NullPointerException – if filename is null.
Returns:
true if the filename represents an absolute path.
Since:
Ant 1.6.3/**
     * Verifies that the specified filename represents an absolute path.
     * Differs from new java.io.File("filename").isAbsolute() in that a path
     * beginning with a double file separator--signifying a Windows UNC--must
     * at minimum match "\\a\b" to be considered an absolute path.
     * @param filename the filename to be checked.
     * @return true if the filename represents an absolute path.
     * @throws java.lang.NullPointerException if filename is null.
     * @since Ant 1.6.3
     */
    public static boolean isAbsolutePath(String filename) {
        if (filename.isEmpty()) {
            return false;
        }
        int len = filename.length();
        char sep = File.separatorChar;
        filename = filename.replace('/', sep).replace('\\', sep);
        char c = filename.charAt(0);
        if (!ON_DOS && !ON_NETWARE) {
            return c == sep;
        }
        if (c == sep) {
            // CheckStyle:MagicNumber OFF
            if (!ON_DOS || len <= 4 || filename.charAt(1) != sep) {
                return false;
            }
            // CheckStyle:MagicNumber ON
            int nextsep = filename.indexOf(sep, 2);
            return nextsep > 2 && nextsep + 1 < len;
        }
        int colon = filename.indexOf(':');
        return (Character.isLetter(c) && colon == 1
                && filename.length() > 2 && filename.charAt(2) == sep)
                || (ON_NETWARE && colon > 0);
    }

    
Translate a path into its native (platform specific) format.

This method uses PathTokenizer to separate the input path
into its components. This handles DOS style paths in a relatively
sensible way. The file separators are then converted to their platform
specific versions.
Params:
toProcess – The path to be translated.
                 May be null.
See Also:
PathTokenizer
Returns:
the native version of the specified path or
        an empty string if the path is null or empty.
Since:
ant 1.7/**
     * Translate a path into its native (platform specific) format.
     * <p>
     * This method uses PathTokenizer to separate the input path
     * into its components. This handles DOS style paths in a relatively
     * sensible way. The file separators are then converted to their platform
     * specific versions.
     *
     * @param toProcess The path to be translated.
     *                  May be <code>null</code>.
     *
     * @return the native version of the specified path or
     *         an empty string if the path is <code>null</code> or empty.
     *
     * @since ant 1.7
     * @see PathTokenizer
     */
    public static String translatePath(String toProcess) {
        if (toProcess == null || toProcess.isEmpty()) {
            return "";
        }
        StringBuilder path = new StringBuilder(toProcess.length() + EXPAND_SPACE);
        PathTokenizer tokenizer = new PathTokenizer(toProcess);
        while (tokenizer.hasMoreTokens()) {
            String pathComponent = tokenizer.nextToken();
            pathComponent = pathComponent.replace('/', File.separatorChar);
            pathComponent = pathComponent.replace('\\', File.separatorChar);
            if (path.length() > 0) {
                path.append(File.pathSeparatorChar);
            }
            path.append(pathComponent);
        }
        return path.toString();
    }

    
"Normalize" the given absolute path.
This includes:

  
Uppercase the drive letter if there is one.
  
Remove redundant slashes after the drive spec.
  
Resolve all ./, .\, ../ and ..\ sequences.
  
DOS style paths that start with a drive letter will have
    \ as the separator.

Unlike File.getCanonicalPath() this method specifically does not resolve symbolic links.
If the path tries to go beyond the file system root (i.e. it
contains more ".." segments than can be travelled up) the
method will return the original path unchanged.
Params:
path – the path to be normalized.
Throws:
NullPointerException – if path is null.
Returns:
the normalized version of the path./**
     * &quot;Normalize&quot; the given absolute path.
     *
     * <p>This includes:
     * <ul>
     *   <li>Uppercase the drive letter if there is one.</li>
     *   <li>Remove redundant slashes after the drive spec.</li>
     *   <li>Resolve all ./, .\, ../ and ..\ sequences.</li>
     *   <li>DOS style paths that start with a drive letter will have
     *     \ as the separator.</li>
     * </ul>
     * <p>Unlike {@link File#getCanonicalPath()} this method
     * specifically does not resolve symbolic links.</p>
     *
     * <p>If the path tries to go beyond the file system root (i.e. it
     * contains more ".." segments than can be travelled up) the
     * method will return the original path unchanged.</p>
     *
     * @param path the path to be normalized.
     * @return the normalized version of the path.
     *
     * @throws java.lang.NullPointerException if path is null.
     */
    public File normalize(final String path) {
        Stack<String> s = new Stack<>();
        String[] dissect = dissect(path);
        s.push(dissect[0]);

        StringTokenizer tok = new StringTokenizer(dissect[1], File.separator);
        while (tok.hasMoreTokens()) {
            String thisToken = tok.nextToken();
            if (".".equals(thisToken)) {
                continue;
            }
            if ("..".equals(thisToken)) {
                if (s.size() < 2) {
                    // Cannot resolve it, so skip it.
                    return new File(path);
                }
                s.pop();
            } else { // plain component
                s.push(thisToken);
            }
        }
        StringBuilder sb = new StringBuilder();
        final int size = s.size();
        for (int i = 0; i < size; i++) {
            if (i > 1) {
                // not before the filesystem root and not after it, since root
                // already contains one
                sb.append(File.separatorChar);
            }
            sb.append(s.elementAt(i));
        }
        return new File(sb.toString());
    }

    
Dissect the specified absolute path.
Params:
path – the path to dissect.
Throws:
NullPointerException – if path is null.
Returns:
String[] {root, remaining path}.
Since:
Ant 1.7/**
     * Dissect the specified absolute path.
     * @param path the path to dissect.
     * @return String[] {root, remaining path}.
     * @throws java.lang.NullPointerException if path is null.
     * @since Ant 1.7
     */
    public String[] dissect(String path) {
        char sep = File.separatorChar;
        path = path.replace('/', sep).replace('\\', sep);

        // make sure we are dealing with an absolute path
        if (!isAbsolutePath(path)) {
            throw new BuildException(path + " is not an absolute path");
        }
        String root;
        int colon = path.indexOf(':');
        if (colon > 0 && (ON_DOS || ON_NETWARE)) {

            int next = colon + 1;
            root = path.substring(0, next);
            char[] ca = path.toCharArray();
            root += sep;
            //remove the initial separator; the root has it.
            next = (ca[next] == sep) ? next + 1 : next;

            StringBuffer sbPath = new StringBuffer();
            // Eliminate consecutive slashes after the drive spec:
            for (int i = next; i < ca.length; i++) {
                if (ca[i] != sep || ca[i - 1] != sep) {
                    sbPath.append(ca[i]);
                }
            }
            path = sbPath.toString();
        } else if (path.length() > 1 && path.charAt(1) == sep) {
            // UNC drive
            int nextsep = path.indexOf(sep, 2);
            nextsep = path.indexOf(sep, nextsep + 1);
            root = (nextsep > 2) ? path.substring(0, nextsep + 1) : path;
            path = path.substring(root.length());
        } else {
            root = File.separator;
            path = path.substring(1);
        }
        return new String[] {root, path};
    }

    
Returns a VMS String representation of a File object.
This is useful since the JVM by default internally converts VMS paths
to Unix style.
The returned String is always an absolute path.
Params:
f – The File to get the VMS path for.
Returns:
The absolute VMS path to f./**
     * Returns a VMS String representation of a <code>File</code> object.
     * This is useful since the JVM by default internally converts VMS paths
     * to Unix style.
     * The returned String is always an absolute path.
     *
     * @param f The <code>File</code> to get the VMS path for.
     * @return The absolute VMS path to <code>f</code>.
     */
    public String toVMSPath(File f) {
        // format: "DEVICE:[DIR.SUBDIR]FILE"
        String osPath;
        String path = normalize(f.getAbsolutePath()).getPath();
        String name = f.getName();
        boolean isAbsolute = path.charAt(0) == File.separatorChar;
        // treat directories specified using .DIR syntax as files
        // CheckStyle:MagicNumber OFF
        boolean isDirectory = f.isDirectory()
                && !name.regionMatches(true, name.length() - 4, ".DIR", 0, 4);
        // CheckStyle:MagicNumber ON
        String device = null;
        StringBuilder directory = null;
        String file = null;

        int index = 0;

        if (isAbsolute) {
            index = path.indexOf(File.separatorChar, 1);
            if (index == -1) {
                return path.substring(1) + ":[000000]";
            }
            device = path.substring(1, index++);
        }
        if (isDirectory) {
            directory = new StringBuilder(path.substring(index).replace(File.separatorChar, '.'));
        } else {
            int dirEnd = path.lastIndexOf(File.separatorChar);
            if (dirEnd == -1 || dirEnd < index) {
                file = path.substring(index);
            } else {
                directory = new StringBuilder(path.substring(index, dirEnd)
                        .replace(File.separatorChar, '.'));
                index = dirEnd + 1;
                if (path.length() > index) {
                    file = path.substring(index);
                }
            }
        }
        if (!isAbsolute && directory != null) {
            directory.insert(0, '.');
        }
        osPath = ((device != null) ? device + ":" : "")
                + ((directory != null) ? "[" + directory + "]" : "")
                + ((file != null) ? file : "");
        return osPath;
    }

    
Create a File object for a temporary file in a given directory. Without
actually creating the file.

The file denoted by the returned abstract pathname did not exist before
this method was invoked, any subsequent invocation of this method will
yield a different file name.


The filename is prefixNNNNNsuffix where NNNN is a random number.

Params:
prefix – 
           prefix before the random number.
suffix – 
           file extension; include the '.'.
parentDir – 
           Directory to create the temporary file in; java.io.tmpdir used
           if not specified.
Deprecated:
since ant 1.7.1 use createTempFile(String, String, File,
boolean, boolean) instead.
Returns:
a File reference to the new, nonexistent temporary file./**
     * Create a File object for a temporary file in a given directory. Without
     * actually creating the file.
     *
     * <p>
     * The file denoted by the returned abstract pathname did not exist before
     * this method was invoked, any subsequent invocation of this method will
     * yield a different file name.
     * </p>
     * <p>
     * The filename is prefixNNNNNsuffix where NNNN is a random number.
     * </p>
     *
     * @param prefix
     *            prefix before the random number.
     * @param suffix
     *            file extension; include the '.'.
     * @param parentDir
     *            Directory to create the temporary file in; java.io.tmpdir used
     *            if not specified.
     *
     * @deprecated since ant 1.7.1 use createTempFile(String, String, File,
     * boolean, boolean) instead.
     * @return a File reference to the new, nonexistent temporary file.
     */
    @Deprecated
    public File createTempFile(String prefix, String suffix, File parentDir) {
        return createTempFile(prefix, suffix, parentDir, false, false);
    }

    private static final String NULL_PLACEHOLDER = "null";

    
Create a temporary file in a given directory.
The file denoted by the returned abstract pathname did not
exist before this method was invoked, any subsequent invocation
of this method will yield a different file name.
Params:
prefix – prefix before the random number.
suffix – file extension; include the '.'.
parentDir – Directory to create the temporary file in;
java.io.tmpdir used if not specified.
deleteOnExit – whether to set the tempfile for deletion on
       normal VM exit.
createFile – true if the file must actually be created. If false
chances exist that a file with the same name is created in the time
between invoking this method and the moment the file is actually created.
If possible set to true.
Returns:
a File reference to the new temporary file.
Since:
Ant 1.7.1/**
     * Create a temporary file in a given directory.
     *
     * <p>The file denoted by the returned abstract pathname did not
     * exist before this method was invoked, any subsequent invocation
     * of this method will yield a different file name.</p>
     *
     * @param prefix prefix before the random number.
     * @param suffix file extension; include the '.'.
     * @param parentDir Directory to create the temporary file in;
     * java.io.tmpdir used if not specified.
     * @param deleteOnExit whether to set the tempfile for deletion on
     *        normal VM exit.
     * @param createFile true if the file must actually be created. If false
     * chances exist that a file with the same name is created in the time
     * between invoking this method and the moment the file is actually created.
     * If possible set to true.
     *
     * @return a File reference to the new temporary file.
     * @since Ant 1.7.1
     */
    public File createTempFile(String prefix, String suffix, File parentDir,
            boolean deleteOnExit, boolean createFile) {
        File result;
        String parent = (parentDir == null)
                ? System.getProperty("java.io.tmpdir")
                : parentDir.getPath();
        if (prefix == null) {
            prefix = NULL_PLACEHOLDER;
        }
        if (suffix == null) {
            suffix = NULL_PLACEHOLDER;
        }

        if (createFile) {
            try {
                result = File.createTempFile(prefix, suffix, new File(parent));
            } catch (IOException e) {
                throw new BuildException("Could not create tempfile in "
                        + parent, e);
            }
        } else {
            DecimalFormat fmt = new DecimalFormat("#####");
            synchronized (rand) {
                do {
                    result = new File(parent, prefix
                            + fmt.format(rand.nextInt(Integer.MAX_VALUE)) + suffix);
                } while (result.exists());
            }
        }

        if (deleteOnExit) {
            result.deleteOnExit();
        }
        return result;
    }

    
Create a File object for a temporary file in a given directory. Without
actually creating the file.

The file denoted by the returned abstract pathname did not exist before
this method was invoked, any subsequent invocation of this method will
yield a different file name.


The filename is prefixNNNNNsuffix where NNNN is a random number.

Params:
prefix – 
           prefix before the random number.
suffix – 
           file extension; include the '.'.
parentDir – 
           Directory to create the temporary file in; java.io.tmpdir used
           if not specified.
deleteOnExit – 
           whether to set the tempfile for deletion on normal VM exit.
Deprecated:
since ant 1.7.1 use createTempFile(String, String, File,
boolean, boolean) instead.
Returns:
a File reference to the new, nonexistent temporary file./**
     * Create a File object for a temporary file in a given directory. Without
     * actually creating the file.
     *
     * <p>
     * The file denoted by the returned abstract pathname did not exist before
     * this method was invoked, any subsequent invocation of this method will
     * yield a different file name.
     * </p>
     * <p>
     * The filename is prefixNNNNNsuffix where NNNN is a random number.
     * </p>
     *
     * @param prefix
     *            prefix before the random number.
     * @param suffix
     *            file extension; include the '.'.
     * @param parentDir
     *            Directory to create the temporary file in; java.io.tmpdir used
     *            if not specified.
     * @param deleteOnExit
     *            whether to set the tempfile for deletion on normal VM exit.
     *
     * @deprecated since ant 1.7.1 use createTempFile(String, String, File,
     * boolean, boolean) instead.
     * @return a File reference to the new, nonexistent temporary file.
     */
    @Deprecated
    public File createTempFile(String prefix, String suffix,
            File parentDir, boolean deleteOnExit) {
        return createTempFile(prefix, suffix, parentDir, deleteOnExit, false);
    }

    
Compares the contents of two files.
Params:
f1 – the file whose content is to be compared.
f2 – the other file whose content is to be compared.
Throws:
IOException – if the files cannot be read.
Returns:
true if the content of the files is the same./**
     * Compares the contents of two files.
     *
     * @param f1 the file whose content is to be compared.
     * @param f2 the other file whose content is to be compared.
     *
     * @return true if the content of the files is the same.
     *
     * @throws IOException if the files cannot be read.
     */
    public boolean contentEquals(File f1, File f2) throws IOException {
        return contentEquals(f1, f2, false);
    }

    
Compares the contents of two files.
Params:
f1 – the file whose content is to be compared.
f2 – the other file whose content is to be compared.
textfile – true if the file is to be treated as a text file and
       differences in kind of line break are to be ignored.
Throws:
IOException – if the files cannot be read.
Returns:
true if the content of the files is the same.
Since:
Ant 1.6.3/**
     * Compares the contents of two files.
     *
     * @param f1 the file whose content is to be compared.
     * @param f2 the other file whose content is to be compared.
     * @param textfile true if the file is to be treated as a text file and
     *        differences in kind of line break are to be ignored.
     *
     * @return true if the content of the files is the same.
     *
     * @throws IOException if the files cannot be read.
     * @since Ant 1.6.3
     */
    public boolean contentEquals(File f1, File f2, boolean textfile) throws IOException {
        return ResourceUtils.contentEquals(new FileResource(f1), new FileResource(f2), textfile);
    }

    
This was originally an emulation of File.getParentFile for JDK 1.1, but it is now implemented using that method (Ant 1.6.3 onwards). 
Params:
f – the file whose parent is required.
Returns:
the given file's parent, or null if the file does not have a parent.
Since:
1.10
Deprecated:
since 1.7. Just use File.getParentFile directly./**
     * This was originally an emulation of {@link File#getParentFile} for JDK 1.1, but it is now
     * implemented using that method (Ant 1.6.3 onwards).
     *
     * @param f the file whose parent is required.
     * @return the given file's parent, or null if the file does not have a parent.
     * @since 1.10
     * @deprecated since 1.7. Just use {@link File#getParentFile} directly.
     */
    @Deprecated
    public File getParentFile(File f) {
        return f == null ? null : f.getParentFile();
    }

    
Read from reader till EOF.
Params:
rdr – the reader from which to read.
Throws:
IOException – if the contents could not be read out from the
        reader.
Returns:
the contents read out of the given reader./**
     * Read from reader till EOF.
     * @param rdr the reader from which to read.
     * @return the contents read out of the given reader.
     *
     * @throws IOException if the contents could not be read out from the
     *         reader.
     */
    public static String readFully(Reader rdr) throws IOException {
        return readFully(rdr, BUF_SIZE);
    }

    
Read from reader till EOF.
Params:
rdr – the reader from which to read.
bufferSize – the buffer size to use when reading.
Throws:
IOException – if the contents could not be read out from the
        reader.
Returns:
the contents read out of the given reader./**
     * Read from reader till EOF.
     *
     * @param rdr the reader from which to read.
     * @param bufferSize the buffer size to use when reading.
     *
     * @return the contents read out of the given reader.
     *
     * @throws IOException if the contents could not be read out from the
     *         reader.
     */
    public static String readFully(Reader rdr, int bufferSize)
        throws IOException {
        if (bufferSize <= 0) {
            throw new IllegalArgumentException(
                "Buffer size must be greater than 0");
        }
        final char[] buffer = new char[bufferSize];
        int bufferLength = 0;
        StringBuilder textBuffer = new StringBuilder();
        while (bufferLength != -1) {
            bufferLength = rdr.read(buffer);
            if (bufferLength > 0) {
                textBuffer.append(buffer, 0, bufferLength);
            }
        }
        return (textBuffer.length() == 0) ? null : textBuffer.toString();
    }

    
Safe read fully - do not return a null for an empty reader.
Params:
reader – the input to read from.
Throws:
IOException – if unable to read from reader.
Returns:
the string.
Since:
Ant 1.7.1/**
     * Safe read fully - do not return a null for an empty reader.
     * @param reader the input to read from.
     * @return the string.
     * @throws IOException if unable to read from reader.
     * @since Ant 1.7.1
     */
    public static String safeReadFully(Reader reader) throws IOException {
        String ret = readFully(reader);
        return ret == null ? "" : ret;
    }

    
This was originally an emulation of File.createNewFile for JDK 1.1,
but it is now implemented using that method (Ant 1.6.3 onwards).
This method has historically not guaranteed that the
operation was atomic. In its current implementation it is.
Params:
f – the file to be created.
Throws:
IOException – on error.
Returns:
true if the file did not exist already.
Since:
Ant 1.5/**
     * This was originally an emulation of File.createNewFile for JDK 1.1,
     * but it is now implemented using that method (Ant 1.6.3 onwards).
     *
     * <p>This method has historically <strong>not</strong> guaranteed that the
     * operation was atomic. In its current implementation it is.
     *
     * @param f the file to be created.
     * @return true if the file did not exist already.
     * @throws IOException on error.
     * @since Ant 1.5
     */
    public boolean createNewFile(File f) throws IOException {
        return f.createNewFile();
    }

    
Create a new file, optionally creating parent directories.
Params:
f – the file to be created.
mkdirs – boolean whether to create parent directories.
Throws:
IOException – on error.
Returns:
true if the file did not exist already.
Since:
Ant 1.6.3/**
     * Create a new file, optionally creating parent directories.
     *
     * @param f the file to be created.
     * @param mkdirs <code>boolean</code> whether to create parent directories.
     * @return true if the file did not exist already.
     * @throws IOException on error.
     * @since Ant 1.6.3
     */
    public boolean createNewFile(File f, boolean mkdirs) throws IOException {
        File parent = f.getParentFile();
        if (mkdirs && !(parent.exists())) {
            parent.mkdirs();
        }
        return f.createNewFile();
    }

    
Checks whether a given file is a symbolic link.
It doesn't really test for symbolic links but whether the
canonical and absolute paths of the file are identical--this
may lead to false positives on some platforms.
Params:
parent – the parent directory of the file to test
name – the name of the file to test.
Throws:
IOException – on error.
Returns:
true if the file is a symbolic link.
Since:
Ant 1.5
Deprecated:
use Files.isSymbolicLink(Path) instead/**
     * Checks whether a given file is a symbolic link.
     *
     * <p>It doesn't really test for symbolic links but whether the
     * canonical and absolute paths of the file are identical--this
     * may lead to false positives on some platforms.</p>
     *
     * @param parent the parent directory of the file to test
     * @param name the name of the file to test.
     *
     * @return true if the file is a symbolic link.
     * @throws IOException on error.
     * @since Ant 1.5
     * @deprecated use {@link Files#isSymbolicLink(Path)} instead
     */
    @Deprecated
    public boolean isSymbolicLink(final File parent, final String name)
        throws IOException {
        if (parent == null) {
            return Files.isSymbolicLink(Paths.get(name));
        }
        return Files.isSymbolicLink(Paths.get(parent.toPath().toString(), name));
    }

    
Removes a leading path from a second path.
This method uses normalize under the covers and does not resolve symbolic links.
Params:
leading – The leading path, must not be null, must be absolute.
path – The path to remove from, must not be null, must be absolute.
Returns:
path's normalized absolute if it doesn't start with
leading; path's path with leading's path removed otherwise.
Since:
Ant 1.5/**
     * Removes a leading path from a second path.
     *
     * <p>This method uses {@link #normalize} under the covers and
     * does not resolve symbolic links.</p>
     *
     * @param leading The leading path, must not be null, must be absolute.
     * @param path The path to remove from, must not be null, must be absolute.
     *
     * @return path's normalized absolute if it doesn't start with
     * leading; path's path with leading's path removed otherwise.
     *
     * @since Ant 1.5
     */
    public String removeLeadingPath(File leading, File path) {
        String l = normalize(leading.getAbsolutePath()).getAbsolutePath();
        String p = normalize(path.getAbsolutePath()).getAbsolutePath();
        if (l.equals(p)) {
            return "";
        }
        // ensure that l ends with a /
        // so we never think /foo was a parent directory of /foobar
        if (!l.endsWith(File.separator)) {
            l += File.separator;
        }
        return (p.startsWith(l)) ? p.substring(l.length()) : p;
    }

    
Learn whether one path "leads" another.
This method uses normalize under the covers and does not resolve symbolic links.
If either path tries to go beyond the file system root
(i.e. it contains more ".." segments than can be travelled up)
the method will return false.
Params:
leading – The leading path, must not be null, must be absolute.
path – The path to check, must not be null, must be absolute.
Returns:
true if path starts with leading; false otherwise.
Since:
Ant 1.7/**
     * Learn whether one path "leads" another.
     *
     * <p>This method uses {@link #normalize} under the covers and
     * does not resolve symbolic links.</p>
     *
     * <p>If either path tries to go beyond the file system root
     * (i.e. it contains more ".." segments than can be travelled up)
     * the method will return false.</p>
     *
     * @param leading The leading path, must not be null, must be absolute.
     * @param path The path to check, must not be null, must be absolute.
     * @return true if path starts with leading; false otherwise.
     * @since Ant 1.7
     */
    public boolean isLeadingPath(File leading, File path) {
        String l = normalize(leading.getAbsolutePath()).getAbsolutePath();
        String p = normalize(path.getAbsolutePath()).getAbsolutePath();
        if (l.equals(p)) {
            return true;
        }
        // ensure that l ends with a /
        // so we never think /foo was a parent directory of /foobar
        if (!l.endsWith(File.separator)) {
            l += File.separator;
        }
        // ensure "/foo/"  is not considered a parent of "/foo/../../bar"
        String up = File.separator + ".." + File.separator;
        if (l.contains(up) || p.contains(up) || (p + File.separator).contains(up)) {
            return false;
        }
        return p.startsWith(l);
    }

    
Learn whether one path "leads" another.
Params:
leading – The leading path, must not be null, must be absolute.
path – The path to check, must not be null, must be absolute.
resolveSymlinks – whether symbolic links shall be resolved
prior to comparing the paths.
Throws:
IOException – if resolveSymlinks is true and invoking
getCanonicaPath on either argument throws an exception
Returns:
true if path starts with leading; false otherwise.
Since:
Ant 1.10.5/**
     * Learn whether one path "leads" another.
     *
     * @param leading The leading path, must not be null, must be absolute.
     * @param path The path to check, must not be null, must be absolute.
     * @param resolveSymlinks whether symbolic links shall be resolved
     * prior to comparing the paths.
     * @return true if path starts with leading; false otherwise.
     * @since Ant 1.10.5
     * @throws IOException if resolveSymlinks is true and invoking
     * getCanonicaPath on either argument throws an exception
     */
    public boolean isLeadingPath(File leading, File path, boolean resolveSymlinks)
        throws IOException {
        if (!resolveSymlinks) {
            return isLeadingPath(leading, path);
        }
        final File l = leading.getCanonicalFile();
        File p = path.getCanonicalFile();
        do {
            if (l.equals(p)) {
                return true;
            }
            p = p.getParentFile();
        } while (p != null);
        return false;
    }

    
Constructs a file: URI that represents the
external form of the given pathname.
Will be an absolute URI if the given path is absolute.
This code encodes non ASCII characters too.
The coding of the output is the same as what File.toURI().toASCIIString() produces
See dt-sysid
which makes some mention of how
characters not supported by URI Reference syntax should be escaped.
Params:
path – the path in the local file system.
Returns:
the URI version of the local path.
Since:
Ant 1.6/**
     * Constructs a <code>file:</code> URI that represents the
     * external form of the given pathname.
     *
     * <p>Will be an absolute URI if the given path is absolute.</p>
     *
     * <p>This code encodes non ASCII characters too.</p>
     *
     * <p>The coding of the output is the same as what File.toURI().toASCIIString() produces</p>
     *
     * See <a href="https://www.w3.org/TR/xml11/#dt-sysid">dt-sysid</a>
     * which makes some mention of how
     * characters not supported by URI Reference syntax should be escaped.
     *
     * @param path the path in the local file system.
     * @return the URI version of the local path.
     * @since Ant 1.6
     */
    public String toURI(String path) {
        return new File(path).toURI().toASCIIString();
    }

    
Constructs a file path from a file: URI.
Will be an absolute path if the given URI is absolute.
Swallows '%' that are not followed by two characters,
doesn't deal with non-ASCII characters.
Params:
uri – the URI designating a file in the local filesystem.
Returns:
the local file system path for the file.
Since:
Ant 1.6/**
     * Constructs a file path from a <code>file:</code> URI.
     *
     * <p>Will be an absolute path if the given URI is absolute.</p>
     *
     * <p>Swallows '%' that are not followed by two characters,
     * doesn't deal with non-ASCII characters.</p>
     *
     * @param uri the URI designating a file in the local filesystem.
     * @return the local file system path for the file.
     * @since Ant 1.6
     */
    public String fromURI(String uri) {
        synchronized (cacheFromUriLock) {
            if (uri.equals(cacheFromUriRequest)) {
                return cacheFromUriResponse;
            }
            String path = Locator.fromURI(uri);
            String ret = isAbsolutePath(path) ? normalize(path).getAbsolutePath() : path;
            cacheFromUriRequest = uri;
            cacheFromUriResponse = ret;
            return ret;
        }
    }

    
Compares two filenames.
Unlike java.io.File#equals this method will try to compare
the absolute paths and "normalize" the filenames
before comparing them.
Params:
f1 – the file whose name is to be compared.
f2 – the other file whose name is to be compared.
Returns:
true if the file are for the same file.
Since:
Ant 1.5.3/**
     * Compares two filenames.
     *
     * <p>Unlike java.io.File#equals this method will try to compare
     * the absolute paths and &quot;normalize&quot; the filenames
     * before comparing them.</p>
     *
     * @param f1 the file whose name is to be compared.
     * @param f2 the other file whose name is to be compared.
     *
     * @return true if the file are for the same file.
     *
     * @since Ant 1.5.3
     */
    public boolean fileNameEquals(File f1, File f2) {
        return normalize(f1.getAbsolutePath()).getAbsolutePath().equals(
                normalize(f2.getAbsolutePath()).getAbsolutePath());
    }

    
Are the two File instances pointing to the same object on the
file system?
Params:
f1 – File
f2 – File
Throws:
IOException – if file name canonicalization fails
Returns:
boolean
Since:
Ant 1.8.2/**
     * Are the two File instances pointing to the same object on the
     * file system?
     *
     * @param f1 File
     * @param f2 File
     * @return boolean
     * @throws IOException if file name canonicalization fails
     * @since Ant 1.8.2
     */
    public boolean areSame(File f1, File f2) throws IOException {
        if (f1 == null && f2 == null) {
            return true;
        }
        if (f1 == null || f2 == null) {
            return false;
        }
        File f1Normalized = normalize(f1.getAbsolutePath());
        File f2Normalized = normalize(f2.getAbsolutePath());
        return f1Normalized.equals(f2Normalized)
            || f1Normalized.getCanonicalFile().equals(f2Normalized
                                                      .getCanonicalFile());
    }

    
Renames a file, even if that involves crossing file system boundaries.
This will remove to (if it exists), ensure that
to's parent directory exists and move
from, which involves deleting from as
well.
Params:
from – the file to move.
to – the new file name.
Throws:
IOException – if anything bad happens during this
process.  Note that to may have been deleted
already when this happens.
Since:
Ant 1.6/**
     * Renames a file, even if that involves crossing file system boundaries.
     *
     * <p>This will remove <code>to</code> (if it exists), ensure that
     * <code>to</code>'s parent directory exists and move
     * <code>from</code>, which involves deleting <code>from</code> as
     * well.</p>
     *
     * @param from the file to move.
     * @param to the new file name.
     * @throws IOException if anything bad happens during this
     * process.  Note that <code>to</code> may have been deleted
     * already when this happens.
     * @since Ant 1.6
     */
    public void rename(File from, File to) throws IOException {
        // identical logic lives in Move.renameFile():
        from = normalize(from.getAbsolutePath()).getCanonicalFile();
        to = normalize(to.getAbsolutePath());
        if (!from.exists()) {
            System.err.println("Cannot rename nonexistent file " + from);
            return;
        }
        if (from.getAbsolutePath().equals(to.getAbsolutePath())) {
            System.err.println("Rename of " + from + " to " + to + " is a no-op.");
            return;
        }
        if (to.exists() && !(areSame(from, to) || tryHardToDelete(to))) {
            throw new IOException("Failed to delete " + to + " while trying to rename " + from);
        }
        File parent = to.getParentFile();
        if (parent != null && !parent.isDirectory()
            && !(parent.mkdirs() || parent.isDirectory())) {
            throw new IOException("Failed to create directory " + parent
                                  + " while trying to rename " + from);
        }
        if (!from.renameTo(to)) {
            copyFile(from, to);
            if (!tryHardToDelete(from)) {
                throw new IOException("Failed to delete " + from + " while trying to rename it.");
            }
        }
    }

    
Get the granularity of file timestamps. The choice is made based on OS, which is
incorrect--it should really be by filesystem. We do not have an easy way to probe for file
systems, however, so this heuristic gives us a decent default.
Returns:
the difference, in milliseconds, which two file timestamps must have in order for the
        two files to be considered to have different timestamps./**
     * Get the granularity of file timestamps. The choice is made based on OS, which is
     * incorrect--it should really be by filesystem. We do not have an easy way to probe for file
     * systems, however, so this heuristic gives us a decent default.
     *
     * @return the difference, in milliseconds, which two file timestamps must have in order for the
     *         two files to be considered to have different timestamps.
     */
    public long getFileTimestampGranularity() {
        if (ON_WIN9X) {
            return FAT_FILE_TIMESTAMP_GRANULARITY;
        }
        if (ON_WINDOWS) {
            return NTFS_FILE_TIMESTAMP_GRANULARITY;
        }
        if (ON_DOS) {
            return FAT_FILE_TIMESTAMP_GRANULARITY;
        }
        return UNIX_FILE_TIMESTAMP_GRANULARITY;
    }

    
test whether a file or directory exists, with an error in the
upper/lower case spelling of the name.
Using this method is only interesting on case insensitive file systems
(Windows).

It will return true only if 3 conditions are met:


  
operating system is case insensitive
  
file exists
  
actual name from directory reading is different from the
      supplied argument


The purpose is to identify files or directories on case-insensitive
filesystems whose case is not what is expected.

Possibly to rename them afterwards to the desired upper/lowercase
combination.
Params:
localFile – file to test
Returns:
true if the file exists and the case of the actual file
             is not the case of the parameter
Since:
Ant 1.7.1/**
     * test whether a file or directory exists, with an error in the
     * upper/lower case spelling of the name.
     * Using this method is only interesting on case insensitive file systems
     * (Windows).
     * <p>
     * It will return true only if 3 conditions are met:
     * </p>
     * <ul>
     *   <li>operating system is case insensitive</li>
     *   <li>file exists</li>
     *   <li>actual name from directory reading is different from the
     *       supplied argument</li>
     * </ul>
     * <p>
     * The purpose is to identify files or directories on case-insensitive
     * filesystems whose case is not what is expected.
     * </p>
     * Possibly to rename them afterwards to the desired upper/lowercase
     * combination.
     *
     * @param localFile file to test
     * @return true if the file exists and the case of the actual file
     *              is not the case of the parameter
     * @since Ant 1.7.1
     */
    public boolean hasErrorInCase(File localFile) {
        localFile = normalize(localFile.getAbsolutePath());
        if (!localFile.exists()) {
            return false;
        }
        final String localFileName = localFile.getName();
        FilenameFilter ff = (dir, name) -> name.equalsIgnoreCase(localFileName)
            && (!name.equals(localFileName));
        String[] names = localFile.getParentFile().list(ff);
        return names != null && names.length == 1;
    }

    
Returns true if the source is older than the dest.
If the dest file does not exist, then the test returns false; it is
implicitly not up do date.
Params:
source – source file (should be the older).
dest – dest file (should be the newer).
granularity – an offset added to the source time.
Returns:
true if the source is older than the dest after accounting
             for granularity.
Since:
Ant 1.6.3/**
     * Returns true if the source is older than the dest.
     * If the dest file does not exist, then the test returns false; it is
     * implicitly not up do date.
     * @param source source file (should be the older).
     * @param dest dest file (should be the newer).
     * @param granularity an offset added to the source time.
     * @return true if the source is older than the dest after accounting
     *              for granularity.
     * @since Ant 1.6.3
     */
    public boolean isUpToDate(File source, File dest, long granularity) {
        //do a check for the destination file existing
        if (!dest.exists()) {
            //if it does not, then the file is not up to date.
            return false;
        }
        long sourceTime = source.lastModified();
        long destTime = dest.lastModified();
        return isUpToDate(sourceTime, destTime, granularity);
    }

    
Returns true if the source is older than the dest.
Params:
source – source file (should be the older).
dest – dest file (should be the newer).
Returns:
true if the source is older than the dest, taking the granularity into account.
Since:
Ant 1.6.3/**
     * Returns true if the source is older than the dest.
     * @param source source file (should be the older).
     * @param dest dest file (should be the newer).
     * @return true if the source is older than the dest, taking the granularity into account.
     * @since Ant 1.6.3
     */
    public boolean isUpToDate(File source, File dest) {
        return isUpToDate(source, dest, getFileTimestampGranularity());
    }

    
Compare two timestamps for being up to date using
the specified granularity.
Params:
sourceTime – timestamp of source file.
destTime – timestamp of dest file.
granularity – os/filesys granularity.
Returns:
true if the dest file is considered up to date./**
     * Compare two timestamps for being up to date using
     * the specified granularity.
     *
     * @param sourceTime timestamp of source file.
     * @param destTime timestamp of dest file.
     * @param granularity os/filesys granularity.
     * @return true if the dest file is considered up to date.
     */
    public boolean isUpToDate(long sourceTime, long destTime, long granularity) {
        return destTime != -1 && destTime >= sourceTime + granularity;
    }

    
Compare two timestamps for being up to date using the
current granularity.
Params:
sourceTime –  timestamp of source file.
destTime –    timestamp of dest file.
Returns:
true if the dest file is considered up to date./**
     * Compare two timestamps for being up to date using the
     * current granularity.
     *
     * @param sourceTime  timestamp of source file.
     * @param destTime    timestamp of dest file.
     * @return true if the dest file is considered up to date.
     */
    public boolean isUpToDate(long sourceTime, long destTime) {
        return isUpToDate(sourceTime, destTime, getFileTimestampGranularity());
    }

    
Close a Writer without throwing any exception if something went wrong.
Do not attempt to close it if the argument is null.
Params:
device – output writer, can be null./**
     * Close a Writer without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     * @param device output writer, can be null.
     */
    public static void close(Writer device) {
        close((AutoCloseable) device);
    }

    
Close a Reader without throwing any exception if something went wrong.
Do not attempt to close it if the argument is null.
Params:
device – Reader, can be null./**
     * Close a Reader without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     *
     * @param device Reader, can be null.
     */
    public static void close(Reader device) {
        close((AutoCloseable) device);
    }

    
Close a stream without throwing any exception if something went wrong.
Do not attempt to close it if the argument is null.
Params:
device – stream, can be null./**
     * Close a stream without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     *
     * @param device stream, can be null.
     */
    public static void close(OutputStream device) {
        close((AutoCloseable) device);
    }

    
Close a stream without throwing any exception if something went wrong.
Do not attempt to close it if the argument is null.
Params:
device – stream, can be null./**
     * Close a stream without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     *
     * @param device stream, can be null.
     */
    public static void close(InputStream device) {
        close((AutoCloseable) device);
    }

    
Close a Channel without throwing any exception if something went wrong.
Do not attempt to close it if the argument is null.
Params:
device – channel, can be null.
Since:
Ant 1.8.0/**
     * Close a Channel without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     *
     * @param device channel, can be null.
     * @since Ant 1.8.0
     */
    public static void close(Channel device) {
        close((AutoCloseable) device);
    }

    
Closes an URLConnection if its concrete implementation provides
a way to close it that Ant knows of.
Params:
conn – connection, can be null
Since:
Ant 1.8.0/**
     * Closes an URLConnection if its concrete implementation provides
     * a way to close it that Ant knows of.
     *
     * @param conn connection, can be null
     * @since Ant 1.8.0
     */
    public static void close(URLConnection conn) {
        if (conn != null) {
            try {
                if (conn instanceof JarURLConnection) {
                    JarURLConnection juc = (JarURLConnection) conn;
                    JarFile jf = juc.getJarFile();
                    jf.close();
                } else if (conn instanceof HttpURLConnection) {
                    ((HttpURLConnection) conn).disconnect();
                }
            } catch (IOException exc) {
                //ignore
            }
        }
    }

    
Close an AutoCloseable without throwing any exception if something went wrong. Do not attempt to close it if the argument is null. 
Params:
ac – AutoCloseable, can be null.
Since:
Ant 1.10.0/**
     * Close an {@link AutoCloseable} without throwing any exception
     * if something went wrong.  Do not attempt to close it if the
     * argument is null.
     *
     * @param ac AutoCloseable, can be null.
     * @since Ant 1.10.0
     */
    public static void close(AutoCloseable ac) {
        if (null != ac) {
            try {
                ac.close();
            } catch (Exception e) {
                //ignore
            }
        }
    }

    
Delete the file with File.delete() if the argument is not null. Do nothing on a null argument. 
Params:
file – file to delete./**
     * Delete the file with {@link File#delete()} if the argument is not null.
     * Do nothing on a null argument.
     * @param file file to delete.
     */
    public static void delete(File file) {
        if (file != null) {
            file.delete();
        }
    }

    
Accommodate Windows bug encountered in both Sun and IBM JDKs.
Others possible. If the delete does not work, call System.gc(),
wait a little and try again.
Params:
f – File
Returns:
whether deletion was successful
Since:
Ant 1.8.0/**
     * Accommodate Windows bug encountered in both Sun and IBM JDKs.
     * Others possible. If the delete does not work, call System.gc(),
     * wait a little and try again.
     *
     * @param f File
     * @return whether deletion was successful
     * @since Ant 1.8.0
     */
    public boolean tryHardToDelete(File f) {
        return tryHardToDelete(f, ON_WINDOWS);
    }

    
If delete does not work, call System.gc() if asked to, wait a
little and try again.
Params:
f – File
runGC – boolean
Returns:
whether deletion was successful
Since:
Ant 1.8.3/**
     * If delete does not work, call System.gc() if asked to, wait a
     * little and try again.
     *
     * @param f File
     * @param runGC boolean
     * @return whether deletion was successful
     * @since Ant 1.8.3
     */
    public boolean tryHardToDelete(File f, boolean runGC) {
        if (!f.delete()) {
            if (runGC) {
                System.gc();
            }
            try {
                Thread.sleep(DELETE_RETRY_SLEEP_MILLIS);
            } catch (InterruptedException ex) {
                // Ignore Exception
            }
            return f.delete();
        }
        return true;
    }

    
Calculates the relative path between two files.

Implementation note:
This function may throw an IOException if an I/O error occurs
because its use of the canonical pathname may require filesystem queries.

Params:
fromFile – the File to calculate the path from
toFile – the File to calculate the path to
Throws:
Exception – for undocumented reasons
See Also:
File.getCanonicalPath()
Returns:
the relative path between the files
Since:
Ant 1.7/**
     * Calculates the relative path between two files.
     * <p>
     * Implementation note:<br>This function may throw an IOException if an I/O error occurs
     * because its use of the canonical pathname may require filesystem queries.
     * </p>
     *
     * @param fromFile the <code>File</code> to calculate the path from
     * @param toFile the <code>File</code> to calculate the path to
     * @return the relative path between the files
     * @throws Exception for undocumented reasons
     * @see File#getCanonicalPath()
     *
     * @since Ant 1.7
     */
    public static String getRelativePath(File fromFile, File toFile) throws Exception { //NOSONAR
        String fromPath = fromFile.getCanonicalPath();
        String toPath = toFile.getCanonicalPath();

        // build the path stack info to compare
        String[] fromPathStack = getPathStack(fromPath);
        String[] toPathStack = getPathStack(toPath);

        if (0 < toPathStack.length && 0 < fromPathStack.length) {
            if (!fromPathStack[0].equals(toPathStack[0])) {
                // not the same device (would be "" on Linux/Unix)
                return getPath(Arrays.asList(toPathStack));
            }
        } else {
            // no comparison possible
            return getPath(Arrays.asList(toPathStack));
        }

        // get index of parts which are equal
        int minLength = Math.min(fromPathStack.length, toPathStack.length);
        int same = 1;
        while (same < minLength && fromPathStack[same].equals(toPathStack[same])) {
            same++;
        }

        List<String> relativePathStack = new ArrayList<>();

        // if "from" part is longer, fill it up with ".."
        // to reach path which is equal to both paths
        for (int i = same; i < fromPathStack.length; i++) {
            relativePathStack.add("..");
        }

        // fill it up path with parts which were not equal
        relativePathStack.addAll(Arrays.asList(toPathStack).subList(same, toPathStack.length));

        return getPath(relativePathStack);
    }

    
Gets all names of the path as an array of Strings.
Params:
path – to get names from
Returns:
Strings, never null
Since:
Ant 1.7/**
     * Gets all names of the path as an array of <code>String</code>s.
     *
     * @param path to get names from
     * @return <code>String</code>s, never <code>null</code>
     *
     * @since Ant 1.7
     */
    public static String[] getPathStack(String path) {
        String normalizedPath = path.replace(File.separatorChar, '/');

        return normalizedPath.split("/");
    }

    
Gets path from a List of Strings.
Params:
pathStack – List of Strings to be concatenated as a path.
Returns:
String, never null
Since:
Ant 1.7/**
     * Gets path from a <code>List</code> of <code>String</code>s.
     *
     * @param pathStack <code>List</code> of <code>String</code>s to be concatenated as a path.
     * @return <code>String</code>, never <code>null</code>
     *
     * @since Ant 1.7
     */
    public static String getPath(List<String> pathStack) {
        // can safely use '/' because Windows understands '/' as separator
        return getPath(pathStack, '/');
    }

    
Gets path from a List of Strings.
Params:
pathStack – List of Strings to be concatenated as a path.
separatorChar – char to be used as separator between names in path
Returns:
String, never null
Since:
Ant 1.7/**
     * Gets path from a <code>List</code> of <code>String</code>s.
     *
     * @param pathStack <code>List</code> of <code>String</code>s to be concatenated as a path.
     * @param separatorChar <code>char</code> to be used as separator between names in path
     * @return <code>String</code>, never <code>null</code>
     *
     * @since Ant 1.7
     */
    public static String getPath(final List<String> pathStack, final char separatorChar) {
        return pathStack.stream().collect(Collectors.joining(Character.toString(separatorChar)));
    }

    
Get the default encoding.
This is done by opening an InputStreamReader on
a dummy InputStream and getting the encoding.
Could use System.getProperty("file.encoding"), but cannot
see where this is documented.
Returns:
the default file encoding./**
     * Get the default encoding.
     * This is done by opening an InputStreamReader on
     * a dummy InputStream and getting the encoding.
     * Could use System.getProperty("file.encoding"), but cannot
     * see where this is documented.
     * @return the default file encoding.
     */
    public String getDefaultEncoding() {
        InputStreamReader is = new InputStreamReader(
            new InputStream() { //NOSONAR
                @Override
                public int read() {
                    return -1;
                }
            });
        try {
            return is.getEncoding();
        } finally {
            close(is);
        }
    }

    
Opens a new OutputStream for the given Path.
Params:
path – the path of the file
append – whether to append to or a replace an existing file
Throws:
IOException – if stream creation fails
Returns:
a stream ready to write to the file
Since:
Ant 1.10.2/**
     * Opens a new OutputStream for the given Path.
     * @param path the path of the file
     * @param append whether to append to or a replace an existing file
     * @return a stream ready to write to the file
     * @throws IOException if stream creation fails
     * @since Ant 1.10.2
     */
    public static OutputStream newOutputStream(Path path, boolean append) throws IOException {
        if (append) {
            return Files.newOutputStream(path, StandardOpenOption.CREATE, StandardOpenOption.APPEND,
                StandardOpenOption.WRITE);
        } else {
            return Files.newOutputStream(path);
        }
    }

    
Tries to determine the case sensitivity of the filesystem corresponding to the path. While doing so, this method might create a temporary file under the directory represented by the path, if it's a directory or in the parent directory of the path, if it's a file. 
 This method works on a best effort basis and will return an Optional.empty() if it cannot determine the case sensitivity, either due to exception or for any other reason. 
Params:
path – The path whose filesystem case sensitivity needs to be checked
Throws:
IllegalArgumentException – If the passed path is null
Returns:
Returns true if the filesystem corresponding to the passed path is case sensitive. Else returns false. If the case sensitivity cannot be determined for whatever reason, this method returns an Optional.empty()
Since:
Ant 1.10.6/**
     * Tries to determine the case sensitivity of the filesystem corresponding to the
     * {@code path}. While doing so, this method might create a temporary file under
     * the directory represented by the {@code path}, if it's a directory or in the
     * parent directory of the {@code path}, if it's a file.
     * <p>
     * This method works on a best effort basis and will return an {@link Optional#empty()}
     * if it cannot determine the case sensitivity, either due to exception or for any other
     * reason.
     * </p>
     * @param path The path whose filesystem case sensitivity needs to be checked
     * @return Returns true if the filesystem corresponding to the passed {@code path}
     *          is case sensitive. Else returns false. If the case sensitivity
     *          cannot be determined for whatever reason, this method returns an
     *          {@link Optional#empty()}
     * @throws IllegalArgumentException If the passed path is null
     * @since Ant 1.10.6
     */
    public static Optional<Boolean> isCaseSensitiveFileSystem(final Path path) {
        if (path == null) {
            throw new IllegalArgumentException("Path cannot be null");
        }
        final String mixedCaseFileNamePrefix = "aNt";
        Path mixedCaseTmpFile = null;
        boolean caseSensitive;
        try {
            if (Files.isRegularFile(path)) {
                mixedCaseTmpFile = Files.createTempFile(path.getParent(), mixedCaseFileNamePrefix, null);
            } else if (Files.isDirectory(path)) {
                mixedCaseTmpFile = Files.createTempFile(path, mixedCaseFileNamePrefix, null);
            } else {
                // we can only do our tricks to figure out whether the filesystem is
                // case sensitive, only if the path is a directory or a file.
                // In other cases (like the path being non-existent), we don't
                // have a way to determine that detail
                return Optional.empty();
            }
            final Path lowerCasePath = Paths.get(mixedCaseTmpFile.toString().toLowerCase(Locale.US));
            try {
                caseSensitive = !Files.isSameFile(mixedCaseTmpFile, lowerCasePath);
            } catch (NoSuchFileException nsfe) {
                // a NSFE implies that the "lowerCasePath" file wasn't considered to be present
                // even if the different cased file exists. That effectively means this is a
                // case sensitive filesystem
                caseSensitive = true;
            }
        } catch (IOException ioe) {
            System.err.println("Could not determine the case sensitivity of the " +
                    "filesystem for path " + path + " due to " + ioe);
            return Optional.empty();
        } finally {
            // delete the tmp file
            if (mixedCaseTmpFile != null) {
                FileUtils.delete(mixedCaseTmpFile.toFile());
            }
        }
        return Optional.of(caseSensitive);
    }
}