001package org.eclipse.aether.named.providers; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022import java.io.IOException; 023import java.io.UncheckedIOException; 024import java.nio.channels.FileChannel; 025import java.nio.file.AccessDeniedException; 026import java.nio.file.Files; 027import java.nio.file.Path; 028import java.nio.file.Paths; 029import java.nio.file.StandardOpenOption; 030import java.util.concurrent.ConcurrentHashMap; 031import java.util.concurrent.ConcurrentMap; 032 033import javax.inject.Named; 034import javax.inject.Singleton; 035 036import org.eclipse.aether.named.support.FileLockNamedLock; 037import org.eclipse.aether.named.support.NamedLockFactorySupport; 038import org.eclipse.aether.named.support.NamedLockSupport; 039 040import static org.eclipse.aether.named.support.Retry.retry; 041 042/** 043 * Named locks factory of {@link FileLockNamedLock}s. This is a bit special implementation, as it 044 * expects locks names to be fully qualified absolute file system paths. 045 * 046 * @since 1.7.3 047 */ 048@Singleton 049@Named( FileLockNamedLockFactory.NAME ) 050public class FileLockNamedLockFactory 051 extends NamedLockFactorySupport 052{ 053 public static final String NAME = "file-lock"; 054 055 /** 056 * Tweak: on Windows, the presence of {@link StandardOpenOption#DELETE_ON_CLOSE} causes concurrency issues. This 057 * flag allows to have it removed from effective flags, at the cost that lockfile directory becomes crowded 058 * with 0 byte sized lock files that are never cleaned up. Default value is {@code true}. 059 * 060 * @see <a href="https://bugs.openjdk.org/browse/JDK-8252883">JDK-8252883</a> 061 */ 062 private static final boolean DELETE_LOCK_FILES = Boolean.parseBoolean( 063 System.getProperty( "aether.named.file-lock.deleteLockFiles", Boolean.TRUE.toString() ) ); 064 065 /** 066 * Tweak: on Windows, the presence of {@link StandardOpenOption#DELETE_ON_CLOSE} causes concurrency issues. This 067 * flag allows to implement similar fix as referenced JDK bug report: retry and hope the best. Default value is 068 * 5 attempts (will retry 4 times). 069 * 070 * @see <a href="https://bugs.openjdk.org/browse/JDK-8252883">JDK-8252883</a> 071 */ 072 private static final int ATTEMPTS = Integer.parseInt( 073 System.getProperty( "aether.named.file-lock.attempts", "5" ) ); 074 075 /** 076 * Tweak: When {@link #ATTEMPTS} used, the amount of milliseconds to sleep between subsequent retries. Default 077 * value is 50 milliseconds. 078 */ 079 private static final long SLEEP_MILLIS = Long.parseLong( 080 System.getProperty( "aether.named.file-lock.sleepMillis", "50" ) ); 081 082 private final ConcurrentMap<String, FileChannel> fileChannels; 083 084 public FileLockNamedLockFactory() 085 { 086 this.fileChannels = new ConcurrentHashMap<>(); 087 } 088 089 @Override 090 protected NamedLockSupport createLock( final String name ) 091 { 092 Path path = Paths.get( name ); 093 FileChannel fileChannel = fileChannels.computeIfAbsent( name, k -> 094 { 095 try 096 { 097 Files.createDirectories( path.getParent() ); 098 FileChannel channel = retry( ATTEMPTS, SLEEP_MILLIS, () -> 099 { 100 try 101 { 102 if ( DELETE_LOCK_FILES ) 103 { 104 return FileChannel.open( 105 path, 106 StandardOpenOption.READ, StandardOpenOption.WRITE, 107 StandardOpenOption.CREATE, StandardOpenOption.DELETE_ON_CLOSE 108 ); 109 } 110 else 111 { 112 return FileChannel.open( 113 path, 114 StandardOpenOption.READ, StandardOpenOption.WRITE, 115 StandardOpenOption.CREATE 116 ); 117 } 118 } 119 catch ( AccessDeniedException e ) 120 { 121 return null; 122 } 123 }, null, null ); 124 125 if ( channel == null ) 126 { 127 throw new IllegalStateException( "Could not open file channel for '" 128 + name + "' after " + ATTEMPTS + " attempts; giving up" ); 129 } 130 return channel; 131 } 132 catch ( InterruptedException e ) 133 { 134 Thread.currentThread().interrupt(); 135 throw new RuntimeException( "Interrupted while opening file channel for '" 136 + name + "'", e ); 137 } 138 catch ( IOException e ) 139 { 140 throw new UncheckedIOException( "Failed to open file channel for '" 141 + name + "'", e ); 142 } 143 } ); 144 return new FileLockNamedLock( name, fileChannel, this ); 145 } 146 147 @Override 148 protected void destroyLock( final String name ) 149 { 150 FileChannel fileChannel = fileChannels.remove( name ); 151 if ( fileChannel == null ) 152 { 153 throw new IllegalStateException( "File channel expected, but does not exist: " + name ); 154 } 155 156 try 157 { 158 fileChannel.close(); 159 } 160 catch ( IOException e ) 161 { 162 throw new UncheckedIOException( "Failed to close file channel for '" 163 + name + "'", e ); 164 } 165 } 166}