package org.eclipse.aether.named.providers;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import java.io.IOException;
  import java.io.UncheckedIOException;
  import java.nio.channels.FileChannel;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.nio.file.StandardOpenOption;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import org.eclipse.aether.named.support.FileLockNamedLock;
  import org.eclipse.aether.named.support.FileSystemFriendly;
  import org.eclipse.aether.named.support.NamedLockFactorySupport;
  import org.eclipse.aether.named.support.NamedLockSupport;
  
  /**
   * Named locks factory of {@link FileLockNamedLock}s. This is a bit special implementation, as it
   * expects locks names to be fully qualified absolute file system paths.
   *
   * @since 1.7.3
   */
  @Singleton
  @Named( FileLockNamedLockFactory.NAME )
  public class FileLockNamedLockFactory
      extends NamedLockFactorySupport
      implements FileSystemFriendly
  {
      public static final String NAME = "file-lock";
  
      private final ConcurrentMap<String, FileChannel> fileChannels;
  
      public FileLockNamedLockFactory()
      {
          this.fileChannels = new ConcurrentHashMap<>();
      }
  
      @Override
      protected NamedLockSupport createLock( final String name )
      {
          Path path = Paths.get( name );
          FileChannel fileChannel = fileChannels.computeIfAbsent( name, k ->
          {
              try
              {
                  Files.createDirectories( path.getParent() );
                  return FileChannel.open(
                          path,
                          StandardOpenOption.READ, StandardOpenOption.WRITE,
                          StandardOpenOption.CREATE, StandardOpenOption.DELETE_ON_CLOSE
                  );
              }
              catch ( IOException e )
              {
                  throw new UncheckedIOException( "Failed to open file channel for '"
                      + name + "'", e );
              }
          } );
          return new FileLockNamedLock( name, fileChannel, this );
      }
  
      @Override
      protected void destroyLock( final String name )
      {
          FileChannel fileChannel = fileChannels.remove( name );
          if ( fileChannel == null )
          {
              throw new IllegalStateException( "File channel expected, but does not exist: " + name );
          }
  
          try
          {
              fileChannel.close();
          }
          catch ( IOException e )
          {
             throw new UncheckedIOException( "Failed to close file channel for '"
                     + name + "'", e );
         }
     }
 }