001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.vfs2.provider;
018
019import org.apache.commons.vfs2.FileName;
020import org.apache.commons.vfs2.FileSystemException;
021import org.apache.commons.vfs2.FileType;
022
023/**
024 * Implementation for layered file systems.
025 * <p>
026 * Additionally encodes the '!' character.
027 * </p>
028 */
029public class LayeredFileNameParser extends AbstractFileNameParser {
030
031    private static final LayeredFileNameParser INSTANCE = new LayeredFileNameParser();
032
033    /**
034     * Gets the singleton instance.
035     *
036     * @return the singleton instance.
037     */
038    public static LayeredFileNameParser getInstance() {
039        return INSTANCE;
040    }
041
042    /**
043     * Constructs a new instance.
044     */
045    public LayeredFileNameParser() {
046        // empty
047    }
048
049    /**
050     * Determines if a character should be encoded.
051     *
052     * @param ch The character to check.
053     * @return true if the character should be encoded.
054     */
055    @Override
056    public boolean encodeCharacter(final char ch) {
057        return super.encodeCharacter(ch) || ch == LayeredFileName.LAYER_SEPARATOR;
058    }
059
060    /**
061     * Pops the root prefix off a URI, which has had the scheme removed.
062     *
063     * @param uri string builder which gets modified.
064     * @return the extracted root name.
065     */
066    protected String extractRootName(final StringBuilder uri) {
067        // Looking for <name>!<abspath> (staring at the end)
068        final int maxlen = uri.length();
069        int pos = maxlen - 1;
070        while (pos > 0 && uri.charAt(pos) != LayeredFileName.LAYER_SEPARATOR) {
071            pos--;
072        }
073
074        if (pos == 0 && uri.charAt(pos) != LayeredFileName.LAYER_SEPARATOR) {
075            // not ! found, so take the whole path a root
076            // e.g. zip:/my/zip/file.zip
077            pos = maxlen;
078        }
079
080        // Extract the name
081        final String prefix = uri.substring(0, pos);
082        if (pos < maxlen) {
083            uri.delete(0, pos + 1);
084        } else {
085            uri.setLength(0);
086        }
087
088        return prefix;
089    }
090
091    /**
092     * Parses the base and name into a FileName.
093     *
094     * @param context The component context.
095     * @param baseFileName The base FileName.
096     * @param fileName name The target file name.
097     * @return The constructed FileName.
098     * @throws FileSystemException if an error occurs.
099     */
100    @Override
101    public FileName parseUri(final VfsComponentContext context, final FileName baseFileName, final String fileName)
102            throws FileSystemException {
103        final StringBuilder name = new StringBuilder();
104
105        // Extract the scheme
106        final String scheme = UriParser.extractScheme(context.getFileSystemManager().getSchemes(), fileName, name);
107
108        // Extract the Layered file URI
109        final String rootUriName = extractRootName(name);
110        FileName rootUri = null;
111        if (rootUriName != null) {
112            rootUri = context.parseURI(rootUriName);
113        }
114
115        // Decode and normalise the path
116        UriParser.canonicalizePath(name, 0, name.length(), this);
117        UriParser.fixSeparators(name);
118        final FileType fileType = UriParser.normalisePath(name);
119        final String path = name.toString();
120
121        return new LayeredFileName(scheme, rootUri, path, fileType);
122    }
123
124}