fileutils.java

java ant的源码！非常值得看的源码

     */
    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
        boolean isDirectory = f.isDirectory()
            && !name.regionMatches(true, name.length() - 4, ".DIR", 0, 4);

        String device = null;
        StringBuffer directory = null;
        String file = null;

        int index = 0;

        if (isAbsolute) {
            index = path.indexOf(File.separatorChar, 1);
            if (index == -1) {
                return path.substring(1) + ":[000000]";
            } else {
                device = path.substring(1, index++);
            }
        }
        if (isDirectory) {
            directory = new StringBuffer(path.substring(index).
                                         replace(File.separatorChar, '.'));
        } else {
            int dirEnd =
                path.lastIndexOf(File.separatorChar, path.length());
            if (dirEnd == -1 || dirEnd < index) {
                file = path.substring(index);
            } else {
                directory = new StringBuffer(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 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>
     * <p>
     * The filename is prefixNNNNNsuffix where NNNN is a random number.
     * </p>
     * <p>This method is different from File.createTempFile() of JDK 1.2
     * as it doesn't create the file itself.  It uses the location pointed
     * to by java.io.tmpdir when the parentDir attribute is null.</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.
     *
     * @return a File reference to the new temporary file.
     * @since Ant 1.5
     */
    public File createTempFile(String prefix, String suffix, File parentDir) {
        return createTempFile(prefix, suffix, parentDir, false);
    }

    /**
     * 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>
     * <p>
     * The filename is prefixNNNNNsuffix where NNNN is a random number.
     * </p>
     * <p>This method is different from File.createTempFile() of JDK 1.2
     * as it doesn't create the file itself.  It uses the location pointed
     * to by java.io.tmpdir when the parentDir attribute is null.</p>
     *
     * @param prefix prefix before the random number.
     * @param suffix file extension; include the '.'.
     * @param parentDir Directory to create the temporary file in;
     * @param deleteOnExit whether to set the tempfile for deletion on
     *        normal VM exit.
     * java.io.tmpdir used if not specified.
     *
     * @return a File reference to the new temporary file.
     * @since Ant 1.7
     */
    public File createTempFile(String prefix, String suffix, File parentDir,
                               boolean deleteOnExit) {
        File result = null;
        String parent = (parentDir == null)
            ? System.getProperty("java.io.tmpdir")
            : parentDir.getPath();

        DecimalFormat fmt = new DecimalFormat("#####");
        synchronized (rand) {
            do {
                result = new File(parent,
                                  prefix + fmt.format(Math.abs(rand.nextInt()))
                                  + suffix);
            } while (result.exists());
        }
        if (deleteOnExit) {
            result.deleteOnExit();
        }
        return result;
    }

    /**
     * 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.
     *
     * @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 {@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.
     */
    public File getParentFile(File f) {
        return (f == null) ? null : f.getParentFile();
    }

    /**
     * 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 final String readFully(Reader rdr) throws IOException {
        return readFully(rdr, BUF_SIZE);
    }

    /**
     * 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 final 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;
        StringBuffer textBuffer = null;
        while (bufferLength != -1) {
            bufferLength = rdr.read(buffer);
            if (bufferLength > 0) {
                textBuffer = (textBuffer == null) ? new StringBuffer() : textBuffer;
                textBuffer.append(new String(buffer, 0, bufferLength));
            }
        }
        return (textBuffer == null) ? null : textBuffer.toString();
    }

    /**
     * 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.
     *
     * @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.
     *
     * <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
     */
    public boolean isSymbolicLink(File parent, String name)
        throws IOException {
        if (parent == null) {
            File f = new File(name);
            parent = f.getParentFile();
            name = f.getName();
        }
        File toTest = new File(parent.getCanonicalPath(), name);
        return !toTest.getAbsolutePath().equals(toTest.getCanonicalPath());
    }

    /**
     * Removes a leading path from a second path.
     *
     * @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.
     * @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 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;
        }
        return p.startsWith(l);
    }

    /**
     * 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="http://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) {
        // #8031: first try Java 1.4.
        Class uriClazz = null;
        try {
            uriClazz = Class.forName("java.net.URI");
        } catch (ClassNotFoundException e) {
            // OK, Java 1.3.
        }
        if (uriClazz != null) {
            try {
                File f = new File(path).getAbsoluteFile();
                java.lang.reflect.Method toURIMethod = File.class.getMethod("toURI", new Class[0]);
                Object uriObj = toURIMethod.invoke(f, new Object[] {});
                java.lang.reflect.Method toASCIIStringMethod
                    = uriClazz.getMethod("toASCIIString", new Class[0]);
                return (String) toASCIIStringMethod.invoke(uriObj, new Object[] {});
            } catch (Exception e) {
                // Reflection problems? Should not happen, debug.
                e.printStackTrace();
            }
        }
        boolean isDir = new File(path).isDirectory();

        StringBuffer sb = new StringBuffer("file:");

        path = resolveFile(null, path).getPath();
        sb.append("//");
        // add an extra slash for filesystems with drive-specifiers
        if (!path.startsWith(File.separator)) {
            sb.append("/");
        }
        path = path.replace('\\', '/');
        try {
            sb.append(Locator.encodeURI(path));
        } catch (UnsupportedEncodingException exc) {
            throw new BuildException(exc);
        }
        if (isDir && !path.endsWith("/")) {
            sb.append('/');
        }
        return sb.toString();
    }

    /**
     * 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.