NormalizedFileNames.java revision 82c11be3dd19fc071f87fedc5782c11ca51a0732 
1/*******************************************************************************
2 * Copyright (c) 2009, 2011 Mountainminds GmbH & Co. KG and Contributors
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 *    Marc R. Hoffmann - initial API and implementation
10 *
11 *******************************************************************************/
12package org.jacoco.report.internal;
13
14import java.util.BitSet;
15import java.util.HashMap;
16import java.util.HashSet;
17import java.util.Map;
18import java.util.Set;
19
20/**
21 * Internal utility to create normalized file names from string ids. The file
22 * names generated by an instance of this class have the following properties:
23 *
24 * <ul>
25 * <li>The same input id is mapped to the same file name.</li>
26 * <li>Different ids are mapped to different file names.</li>
27 * <li>For safe characters the file name corresponds to the input id, other
28 * characters are replaced by <code>_</code> (underscore).</li>
29 * <li>File names are case aware, i.e. the same file name but with different
30 * upper/lower case characters is not possible.</li>
31 * <li>If unique filenames can't directly created from the ids, additional
32 * suffixes are appended.</li>
33 * </ul>
34 */
35class NormalizedFileNames {
36
37	private static final BitSet LEGAL_CHARS = new BitSet();
38
39	static {
40		final String legal = "abcdefghijklmnopqrstuvwxyz"
41				+ "ABCDEFGHIJKLMNOPQRSTUVWYXZ0123456789$-._";
42		for (final char c : legal.toCharArray()) {
43			LEGAL_CHARS.set(c);
44		}
45	}
46
47	private final Map<String, String> mapping = new HashMap<String, String>();
48
49	private final Set<String> usedNames = new HashSet<String>();
50
51	public String getFileName(final String id) {
52		String name = mapping.get(id);
53		if (name != null) {
54			return name;
55		}
56		name = replaceIllegalChars(id);
57		name = ensureUniqueness(name);
58		mapping.put(id, name);
59		return name;
60	}
61
62	private String replaceIllegalChars(final String s) {
63		final StringBuilder sb = new StringBuilder(s.length());
64		for (int i = 0; i < s.length(); i++) {
65			final char c = s.charAt(i);
66			sb.append(LEGAL_CHARS.get(c) ? c : '_');
67		}
68		return sb.toString();
69	}
70
71	private String ensureUniqueness(final String s) {
72		String unique = s;
73		String lower = unique.toLowerCase();
74		int idx = 1;
75		while (usedNames.contains(lower)) {
76			unique = s + '~' + idx++;
77			lower = unique.toLowerCase();
78		}
79		usedNames.add(lower);
80		return unique;
81	}
82
83}
84