1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.eclipse.aether.internal.impl.synccontext.named;
20
21 import java.util.Collection;
22 import java.util.stream.Collectors;
23
24 import org.eclipse.aether.RepositorySystemSession;
25 import org.eclipse.aether.artifact.Artifact;
26 import org.eclipse.aether.metadata.Metadata;
27 import org.eclipse.aether.util.ConfigUtils;
28 import org.eclipse.aether.util.StringDigestUtil;
29
30 import static java.util.Objects.requireNonNull;
31
32 /**
33 * Wrapping {@link NameMapper}, that wraps another {@link NameMapper} and hashes resulting strings. It makes use of
34 * fact that (proper) Hash will create unique fixed length string for each different input string (so injection still
35 * stands). This mapper produces file system friendly names. Supports different "depths" (0-4 inclusive) where the
36 * name will contain 0 to 4 level deep directories.
37 * <p>
38 * This mapper is usable in any scenario, but intent was to produce more "compact" name mapper for file locking.
39 *
40 * @since 1.9.0
41 */
42 public class HashingNameMapper implements NameMapper {
43 /**
44 * The depth how many levels should adapter create. Acceptable values are 0-4 (inclusive).
45 *
46 * @configurationSource {@link RepositorySystemSession#getConfigProperties()}
47 * @configurationType {@link java.lang.Integer}
48 * @configurationDefaultValue {@link #DEFAULT_DEPTH}
49 */
50 public static final String CONFIG_PROP_DEPTH = NamedLockFactoryAdapter.CONFIG_PROPS_PREFIX + "hashing.depth";
51
52 public static final int DEFAULT_DEPTH = 2;
53
54 private final NameMapper delegate;
55
56 public HashingNameMapper(final NameMapper delegate) {
57 this.delegate = requireNonNull(delegate);
58 }
59
60 @Override
61 public boolean isFileSystemFriendly() {
62 return true; // hashes delegated strings, so whatever it wrapped, it does not come through
63 }
64
65 @Override
66 public Collection<String> nameLocks(
67 RepositorySystemSession session,
68 Collection<? extends Artifact> artifacts,
69 Collection<? extends Metadata> metadatas) {
70 final int depth = ConfigUtils.getInteger(session, DEFAULT_DEPTH, CONFIG_PROP_DEPTH);
71 if (depth < 0 || depth > 4) {
72 throw new IllegalArgumentException("allowed depth value is between 0 and 4 (inclusive)");
73 }
74 return delegate.nameLocks(session, artifacts, metadatas).stream()
75 .map(n -> hashName(n, depth))
76 .collect(Collectors.toList());
77 }
78
79 private String hashName(final String name, final int depth) {
80 String hashedName = StringDigestUtil.sha1(name);
81 if (depth == 0) {
82 return hashedName;
83 }
84 StringBuilder prefix = new StringBuilder();
85 int i = 0;
86 while (i < hashedName.length() && i / 2 < depth) {
87 prefix.append(hashedName, i, i + 2).append("/");
88 i += 2;
89 }
90 return prefix.append(hashedName).toString();
91 }
92 }