PathHelper.java

/*
 * Copyright 2010 netling project <http://netling.org>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.netling.sftp;

import java.io.IOException;

public class PathHelper {

    private final SFTPEngine engine;
    private String dotDir;

    public PathHelper(SFTPEngine engine) {
        this.engine = engine;
    }

    public PathComponents getComponents(String path)
            throws IOException {
        if (path.isEmpty() || path.equals("."))
            return getComponents(getDotDir());

        final int lastSlash = path.lastIndexOf("/");

        if (lastSlash == -1)
            if (path.equals(".."))
                return getComponents(canon(path));
            else
                return new PathComponents(getDotDir(), path);

        final String name = path.substring(lastSlash + 1);

        if (name.equals(".") || name.equals(".."))
            return getComponents(canon(path));
        else {
            final String parent = path.substring(0, lastSlash);
            return new PathComponents(parent, name);
        }
    }

    private synchronized String getDotDir()
            throws IOException {
        return (dotDir != null) ? dotDir : (dotDir = canon("."));
    }

    private String canon(String path)
            throws IOException {
        return engine.canonicalize(path);
    }

}