fileutils.java

Use the links below to download a source distribution of Ant from one of our mirrors. It is good pra

     * 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;
        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();
    }

    /**
     * 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.
     */
    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).
     *
     * <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.
     * @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.
     *
     * <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());
    }

    /**
     * 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 {
        from = normalize(from.getAbsolutePath()).getCanonicalFile();
        to = normalize(to.getAbsolutePath());
        if (!from.exists()) {
            System.err.println("Cannot rename nonexistent file " + from);
            return;
        }
        if (from.equals(to)) {
            System.err.println("Rename of " + from + " to " + to + " is a no-op.");
            return;
        }
        if (to.exists() && !(from.equals(to.getCanonicalFile()) || to.delete())) {
            throw new IOException("Failed to delete " + to + " while trying to rename " + from);
        }
        File parent = to.getParentFile();
        if (parent != null && !parent.exists() && !parent.mkdirs()) {
            throw new IOException("Failed to create directory " + parent
                                  + " while trying to rename " + from);
        }
        if (!from.renameTo(to)) {
            copyFile(from, to);
            if (!from.delete()) {
                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.
     *
     * @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;
    }