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.named.providers;
20
21 import javax.inject.Named;
22 import javax.inject.Singleton;
23
24 import java.io.IOException;
25 import java.io.UncheckedIOException;
26 import java.nio.channels.FileChannel;
27 import java.nio.file.AccessDeniedException;
28 import java.nio.file.Files;
29 import java.nio.file.Path;
30 import java.nio.file.Paths;
31 import java.nio.file.StandardOpenOption;
32 import java.util.concurrent.ConcurrentHashMap;
33 import java.util.concurrent.ConcurrentMap;
34
35 import org.eclipse.aether.named.support.FileLockNamedLock;
36 import org.eclipse.aether.named.support.NamedLockFactorySupport;
37 import org.eclipse.aether.named.support.NamedLockSupport;
38
39 import static org.eclipse.aether.named.support.Retry.retry;
40
41 /**
42 * Named locks factory of {@link FileLockNamedLock}s. This is a bit special implementation, as it
43 * expects locks names to be fully qualified absolute file system paths.
44 *
45 * @since 1.7.3
46 */
47 @Singleton
48 @Named(FileLockNamedLockFactory.NAME)
49 public class FileLockNamedLockFactory extends NamedLockFactorySupport {
50 public static final String NAME = "file-lock";
51
52 /**
53 * Tweak: on Windows, the presence of {@link StandardOpenOption#DELETE_ON_CLOSE} causes concurrency issues. This
54 * flag allows to have it removed from effective flags, at the cost that lockfile directory becomes crowded
55 * with 0 byte sized lock files that are never cleaned up. Default value is {@code true}.
56 *
57 * @see <a href="https://bugs.openjdk.org/browse/JDK-8252883">JDK-8252883</a>
58 * @configurationSource {@link System#getProperty(String, String)}
59 * @configurationType {@link java.lang.Boolean}
60 * @configurationDefaultValue true
61 */
62 public static final String SYSTEM_PROP_DELETE_LOCK_FILES = "aether.named.file-lock.deleteLockFiles";
63
64 private static final boolean DELETE_LOCK_FILES =
65 Boolean.parseBoolean(System.getProperty(SYSTEM_PROP_DELETE_LOCK_FILES, Boolean.TRUE.toString()));
66
67 /**
68 * Tweak: on Windows, the presence of {@link StandardOpenOption#DELETE_ON_CLOSE} causes concurrency issues. This
69 * flag allows to implement similar fix as referenced JDK bug report: retry and hope the best. Default value is
70 * 5 attempts (will retry 4 times).
71 *
72 * @see <a href="https://bugs.openjdk.org/browse/JDK-8252883">JDK-8252883</a>
73 * @configurationSource {@link System#getProperty(String, String)}
74 * @configurationType {@link java.lang.Integer}
75 * @configurationDefaultValue 5
76 */
77 public static final String SYSTEM_PROP_ATTEMPTS = "aether.named.file-lock.attempts";
78
79 private static final int ATTEMPTS = Integer.parseInt(System.getProperty(SYSTEM_PROP_ATTEMPTS, "5"));
80
81 /**
82 * Tweak: When {@link #SYSTEM_PROP_ATTEMPTS} used, the amount of milliseconds to sleep between subsequent retries. Default
83 * value is 50 milliseconds.
84 *
85 * @configurationSource {@link System#getProperty(String, String)}
86 * @configurationType {@link java.lang.Long}
87 * @configurationDefaultValue 50
88 */
89 public static final String SYSTEM_PROP_SLEEP_MILLIS = "aether.named.file-lock.sleepMillis";
90
91 private static final long SLEEP_MILLIS = Long.parseLong(System.getProperty(SYSTEM_PROP_SLEEP_MILLIS, "50"));
92
93 private final ConcurrentMap<String, FileChannel> fileChannels;
94
95 public FileLockNamedLockFactory() {
96 this.fileChannels = new ConcurrentHashMap<>();
97 }
98
99 @Override
100 protected NamedLockSupport createLock(final String name) {
101 Path path = Paths.get(name);
102 FileChannel fileChannel = fileChannels.computeIfAbsent(name, k -> {
103 try {
104 Files.createDirectories(path.getParent());
105 FileChannel channel = retry(
106 ATTEMPTS,
107 SLEEP_MILLIS,
108 () -> {
109 try {
110 if (DELETE_LOCK_FILES) {
111 return FileChannel.open(
112 path,
113 StandardOpenOption.READ,
114 StandardOpenOption.WRITE,
115 StandardOpenOption.CREATE,
116 StandardOpenOption.DELETE_ON_CLOSE);
117 } else {
118 return FileChannel.open(
119 path,
120 StandardOpenOption.READ,
121 StandardOpenOption.WRITE,
122 StandardOpenOption.CREATE);
123 }
124 } catch (AccessDeniedException e) {
125 return null;
126 }
127 },
128 null,
129 null);
130
131 if (channel == null) {
132 throw new IllegalStateException("Could not open file channel for '" + name + "' after "
133 + SYSTEM_PROP_ATTEMPTS + " attempts; giving up");
134 }
135 return channel;
136 } catch (InterruptedException e) {
137 Thread.currentThread().interrupt();
138 throw new RuntimeException("Interrupted while opening file channel for '" + name + "'", e);
139 } catch (IOException e) {
140 throw new UncheckedIOException("Failed to open file channel for '" + name + "'", e);
141 }
142 });
143 return new FileLockNamedLock(name, fileChannel, this);
144 }
145
146 @Override
147 protected void destroyLock(final String name) {
148 FileChannel fileChannel = fileChannels.remove(name);
149 if (fileChannel == null) {
150 throw new IllegalStateException("File channel expected, but does not exist: " + name);
151 }
152
153 try {
154 fileChannel.close();
155 } catch (IOException e) {
156 throw new UncheckedIOException("Failed to close file channel for '" + name + "'", e);
157 }
158 }
159 }