content: /*
   * 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.
   */
  
  package org.apache.cassandra.io.util;
  
  import java.io.IOException;
  import java.nio.file.FileSystem;
  
  import com.google.common.base.StandardSystemProperty;
  import com.google.common.jimfs.Configuration;
  import com.google.common.jimfs.Jimfs;
  
  import org.apache.cassandra.io.filesystem.ForwardingFileSystem;
  import org.apache.cassandra.io.filesystem.ListenableFileSystem;
  
  public class FileSystems
  {
      public static ListenableFileSystem newGlobalInMemoryFileSystem()
      {
          return global(jimfs());
      }
  
      public static ListenableFileSystem global()
      {
          return global(File.unsafeGetFilesystem());
      }
  
      public static ListenableFileSystem global(FileSystem real)
      {
          FileSystem current = File.unsafeGetFilesystem();
          ListenableFileSystem fs = new ListenableFileSystem(new ForwardingFileSystem(real)
          {
              @Override
              public void close() throws IOException
              {
                  try
                  {
                      super.close();
                  }
                  finally
                  {
                      File.unsafeSetFilesystem(current);
                  }
              }
          });
          File.unsafeSetFilesystem(fs);
          return fs;
      }
  
      public static FileSystem jimfs()
      {
          return Jimfs.newFileSystem(jimfsConfig());
      }
  
      public static FileSystem jimfs(String name)
      {
          return Jimfs.newFileSystem(name, jimfsConfig());
      }
  
      private static Configuration jimfsConfig()
      {
          return Configuration.unix().toBuilder()
                              .setMaxSize(4L << 30).setBlockSize(512)
                              .build();
      }
  
      public static File maybeCreateTmp()
      {
          File dir = new File(StandardSystemProperty.JAVA_IO_TMPDIR.value());
          if (!dir.exists())
              dir.tryCreateDirectories();
          return dir;
      }
  }
  