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.hints;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import javax.crypto.Cipher;
  
  import com.google.common.annotations.VisibleForTesting;
  
  import io.netty.util.concurrent.FastThreadLocal;
  import org.apache.cassandra.security.EncryptionUtils;
  import org.apache.cassandra.io.FSReadError;
  import org.apache.cassandra.io.compress.ICompressor;
  import org.apache.cassandra.io.util.ChannelProxy;
  import org.apache.cassandra.utils.Throwables;
  
  public class EncryptedChecksummedDataInput extends ChecksummedDataInput
  {
      private static final FastThreadLocal<ByteBuffer> reusableBuffers = new FastThreadLocal<ByteBuffer>()
      {
          protected ByteBuffer initialValue()
          {
              return ByteBuffer.allocate(0);
          }
      };
  
      private final Cipher cipher;
      private final ICompressor compressor;
  
      private final EncryptionUtils.ChannelProxyReadChannel readChannel;
      private long sourcePosition;
  
      protected EncryptedChecksummedDataInput(ChannelProxy channel, Cipher cipher, ICompressor compressor, long filePosition)
      {
          super(channel);
          this.cipher = cipher;
          this.compressor = compressor;
          readChannel = new EncryptionUtils.ChannelProxyReadChannel(channel, filePosition);
          this.sourcePosition = filePosition;
          assert cipher != null;
          assert compressor != null;
      }
  
      /**
       * Since an entire block of compressed data is read off of disk, not just a hint at a time,
       * we don't report EOF until the decompressed data has also been read completely
       */
      public boolean isEOF()
      {
          return readChannel.getCurrentPosition() == channel.size() && buffer.remaining() == 0;
      }
  
      public long getSourcePosition()
      {
          return sourcePosition;
      }
  
      static class Position extends ChecksummedDataInput.Position
      {
          final long bufferStart;
          final int bufferPosition;
  
          public Position(long sourcePosition, long bufferStart, int bufferPosition)
          {
              super(sourcePosition);
              this.bufferStart = bufferStart;
              this.bufferPosition = bufferPosition;
          }
  
          @Override
          public long subtract(InputPosition o)
          {
              Position other = (Position) o;
              return bufferStart - other.bufferStart + bufferPosition - other.bufferPosition;
          }
      }
  
      public InputPosition getSeekPosition()
      {
          return new Position(sourcePosition, bufferOffset, buffer.position());
      }
  
      public void seek(InputPosition p)
      {
          Position pos = (Position) p;
          bufferOffset = pos.bufferStart;
          readChannel.setPosition(pos.sourcePosition);
          buffer.position(0).limit(0);
          resetCrc();
          reBuffer();
          buffer.position(pos.bufferPosition);
          assert sourcePosition == pos.sourcePosition;
          assert bufferOffset == pos.bufferStart;
          assert buffer.position() == pos.bufferPosition;
      }
  
      @Override
      protected void readBuffer()
      {
          this.sourcePosition = readChannel.getCurrentPosition();
          if (isEOF())
              return;
  
          try
          {
              ByteBuffer byteBuffer = reusableBuffers.get();
              ByteBuffer decrypted = EncryptionUtils.decrypt(readChannel, byteBuffer, true, cipher);
              buffer = EncryptionUtils.uncompress(decrypted, buffer, true, compressor);
  
              if (decrypted.capacity() > byteBuffer.capacity())
                  reusableBuffers.set(decrypted);
          }
          catch (IOException ioe)
          {
              throw new FSReadError(ioe, getPath());
          }
      }
  
      public static ChecksummedDataInput upgradeInput(ChecksummedDataInput input, Cipher cipher, ICompressor compressor)
      {
          long position = input.getPosition();
          input.close();
  
          ChannelProxy channel = new ChannelProxy(input.getPath());
          try
          {
              return new EncryptedChecksummedDataInput(channel, cipher, compressor, position);
          }
          catch (Throwable t)
          {
              throw Throwables.cleaned(channel.close(t));
          }
      }
  
      @VisibleForTesting
      Cipher getCipher()
      {
          return cipher;
      }
  
      @VisibleForTesting
      ICompressor getCompressor()
      {
          return compressor;
      }
  }
  