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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.util;
20  
21  import java.io.IOException;
22  import java.nio.file.Files;
23  import java.nio.file.Path;
24  import java.nio.file.Paths;
25  
26  import org.eclipse.aether.RepositorySystemSession;
27  import org.eclipse.aether.repository.LocalRepository;
28  
29  import static java.util.Objects.requireNonNull;
30  
31  /**
32   * A utility class to calculate (and create if needed) paths backed by directories using configuration properties from
33   * repository system session and others.
34   *
35   * @see RepositorySystemSession#getConfigProperties()
36   * @see RepositorySystemSession#getLocalRepository()
37   * @since 1.9.0
38   */
39  public final class DirectoryUtils {
40      private DirectoryUtils() {
41          // hide constructor
42      }
43  
44      /**
45       * Creates {@link Path} instance out of passed in {@code name} parameter. May create a directory on resulting path,
46       * if not exist, when invoked with {@code mayCreate} being {@code true}. Never returns {@code null}.
47       * <p>
48       * Following outcomes may happen:
49       * <ul>
50       *     <li>{@code name} is absolute path - results in {@link Path} instance created directly from name.</li>
51       *     <li>{@code name} is relative path - results in {@link Path} instance resolved against {@code base} parameter.
52       *     </li>
53       * </ul>
54       * Resulting path is being checked is a directory, and if not, it will be created if {@code mayCreate} is
55       * {@code true}. If resulting path exist but is not a directory, this method will throw.
56       *
57       * @param name      The name to create directory with, cannot be {@code null}.
58       * @param base      The base {@link Path} to resolve name, if it is relative path, cannot be {@code null}.
59       * @param mayCreate If resulting path does not exist, should it create?
60       * @return The {@link Path} instance that is resolved and backed by existing directory.
61       * @throws IOException If some IO related errors happens.
62       */
63      public static Path resolveDirectory(String name, Path base, boolean mayCreate) throws IOException {
64          requireNonNull(name, "name is null");
65          requireNonNull(base, "base is null");
66          final Path namePath = Paths.get(name);
67          final Path result;
68          if (namePath.isAbsolute()) {
69              result = namePath.normalize();
70          } else {
71              result = base.resolve(name).normalize();
72          }
73  
74          if (!Files.exists(result)) {
75              if (mayCreate) {
76                  Files.createDirectories(result);
77              }
78          } else if (!Files.isDirectory(result)) {
79              throw new IOException("Path exists, but is not a directory: " + result);
80          }
81          return result;
82      }
83  
84      /**
85       * Creates {@link Path} instance out of session configuration, and (if relative) resolve it against local
86       * repository basedir. Pre-populates values and invokes {@link #resolveDirectory(String, Path, boolean)}.
87       * <p>
88       * For this method to work, {@link LocalRepository#getBasePath()} must return
89       * non-{@code null} value, otherwise {@link NullPointerException} is thrown.
90       *
91       * @param session     The session, may not be {@code null}.
92       * @param defaultName The default value if not present in session configuration, may not be {@code null}.
93       * @param nameKey     The key to look up for in session configuration to obtain user set value.
94       * @param mayCreate   If resulting path does not exist, should it create?
95       * @return The {@link Path} instance that is resolved and backed by existing directory.
96       * @throws IOException If some IO related errors happens.
97       * @see #resolveDirectory(String, Path, boolean)
98       */
99      public static Path resolveDirectory(
100             RepositorySystemSession session, String defaultName, String nameKey, boolean mayCreate) throws IOException {
101         requireNonNull(session, "session is null");
102         requireNonNull(defaultName, "defaultName is null");
103         requireNonNull(nameKey, "nameKey is null");
104         requireNonNull(session.getLocalRepository().getBasePath(), "session.localRepository.basePath is null");
105         return resolveDirectory(
106                 ConfigUtils.getString(session, defaultName, nameKey),
107                 session.getLocalRepository().getBasePath(),
108                 mayCreate);
109     }
110 }