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;
  
  /**
   * Rebufferer for memory-mapped files. Thread-safe and shared among reader instances.
   * This is simply a thin wrapper around MmappedRegions as the buffers there can be used directly after duplication.
   */
  class MmapRebufferer extends AbstractReaderFileProxy implements Rebufferer, RebuffererFactory
  {
      protected final MmappedRegions regions;
  
      MmapRebufferer(ChannelProxy channel, long fileLength, MmappedRegions regions)
      {
          super(channel, fileLength);
          this.regions = regions;
      }
  
      @Override
      public BufferHolder rebuffer(long position)
      {
          return regions.floor(position);
      }
  
      @Override
      public Rebufferer instantiateRebufferer(boolean isScan)
      {
          return this;
      }
  
      @Override
      public void close()
      {
          regions.closeQuietly();
      }
  
      @Override
      public void closeReader()
      {
          // Instance is shared among readers. Nothing to release.
      }
  
      @Override
      public String toString()
      {
          return String.format("%s(%s - data length %d)",
                               getClass().getSimpleName(),
                               channel.filePath(),
                               fileLength());
      }
  }
  