/*
 * 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.hadoop.ozone.client.io;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import org.apache.hadoop.fs.ByteBufferReadable;
import org.apache.hadoop.fs.CanUnbuffer;
import org.apache.hadoop.fs.Seekable;

/**
 * OzoneInputStream is used to read data from Ozone.
 * It uses {@link KeyInputStream} for reading the data.
 */
public class OzoneInputStream extends InputStream implements CanUnbuffer,
    ByteBufferReadable, Seekable {

  private final InputStream inputStream;

  public OzoneInputStream() {
    inputStream = null;
  }

  /**
   * Constructs OzoneInputStream with KeyInputStream.
   *
   * @param inputStream
   */
  public OzoneInputStream(InputStream inputStream) {
    this.inputStream = inputStream;
  }

  @Override
  public int read() throws IOException {
    return inputStream.read();
  }

  @Override
  public int read(byte[] b, int off, int len) throws IOException {
    return inputStream.read(b, off, len);
  }

  @Override
  public int read(ByteBuffer byteBuffer) throws IOException {
    if (inputStream instanceof ByteBufferReadable) {
      return ((ByteBufferReadable)inputStream).read(byteBuffer);
    } else {
      throw new UnsupportedOperationException("Read with ByteBuffer is not " +
          " supported by " + inputStream.getClass().getName());
    }
  }

  @Override
  public synchronized void close() throws IOException {
    inputStream.close();
  }

  @Override
  public int available() throws IOException {
    return inputStream.available();
  }

  @Override
  public long skip(long n) throws IOException {
    return inputStream.skip(n);
  }

  public InputStream getInputStream() {
    return inputStream;
  }

  @Override
  public void unbuffer() {
    if (inputStream instanceof CanUnbuffer) {
      ((CanUnbuffer) inputStream).unbuffer();
    }
  }

  @Override
  public void seek(long pos) throws IOException {
    if (inputStream instanceof Seekable) {
      ((Seekable) inputStream).seek(pos);
    } else {
      throw new UnsupportedOperationException("Seek is not supported on the " +
          "underlying inputStream");
    }
  }

  @Override
  public long getPos() throws IOException {
    if (inputStream instanceof Seekable) {
      return ((Seekable) inputStream).getPos();
    } else {
      throw new UnsupportedOperationException("Seek is not supported on the " +
          "underlying inputStream");
    }
  }

  @Override
  public boolean seekToNewSource(long targetPos) throws IOException {
    if (inputStream instanceof Seekable) {
      return ((Seekable) inputStream).seekToNewSource(targetPos);
    } else {
      throw new UnsupportedOperationException("Seek is not supported on the " +
          "underlying inputStream");
    }
  }
}
