NfsReadResponse.java

/**
 * Copyright 2016-2018 Dell Inc. or its subsidiaries. All rights reserved.
 *
 * <p>Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
 * except in compliance with the License. A copy of the License is located at
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 * <p>or in the "license" file accompanying this file. This file 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 com.emc.ecs.nfsclient.nfs;

import com.emc.ecs.nfsclient.rpc.RpcException;
import com.emc.ecs.nfsclient.rpc.Xdr;

/**
 * The response, as specified by RFC 1813 (https://tools.ietf.org/html/rfc1813).
 *
 * <p>Procedure READ reads data from a file.
 *
 * @author seibed
 */
public class NfsReadResponse extends NfsResponseBase {

  /** The number read. */
  private int _bytesRead;

  /**
   * <ul>
   *   <li><code>true</code> if the end of file is reached.
   *   <li><code>false</code> otherwise.
   * </ul>
   */
  private boolean _eof;

  /** The buffer for storing bytes. */
  private byte[] _bytes;

  /** The beginning position of the buffer to store bytes */
  private int _position;

  /**
   * Creates the response, as specified by RFC 1813 (https://tools.ietf.org/html/rfc1813).
   *
   * <p>Procedure READ reads data from a file.
   *
   * @param bytes the buffer for storing bytes
   * @param position the beginning position of buffer to store bytes
   * @param nfsVersion The NFS version number. This is ignored for now, as only NFSv3 is supported,
   *     but is included to allow future support for other versions.
   */
  public NfsReadResponse(byte[] bytes, int position, int nfsVersion) {
    super();
    _bytes = bytes;
    _position = position;
  }

  /** {@inheritDoc} */
  @Override
  public void unmarshalling(Xdr xdr) throws RpcException {
    super.unmarshalling(xdr);
    unmarshallingAttributes(xdr);
    if (stateIsOk()) {
      _bytesRead = xdr.getInt();
      _eof = xdr.getBoolean();
      if (_bytes == null) {
        _bytes = new byte[_bytesRead];
        _position = 0;
      }
      xdr.getBytes(xdr.getInt(), _bytes, _position);
    }
  }

  /** Returns the number read. */
  public int getBytesRead() {
    return _bytesRead;
  }

  /**
   * Returns
   *
   * <ul>
   *   <li><code>true</code> if the end of file is reached.
   *   <li><code>false</code> otherwise.
   * </ul>
   *
   * .
   */
  public boolean isEof() {
    return _eof;
  }

  /** Returns the buffer, or null if there was none. */
  public byte[] getBytes() {
    return (_bytes == null) ? null : _bytes.clone();
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder();
    sb.append("read-response");
    sb.append(" bytes-read:");
    sb.append(String.valueOf(_bytesRead));
    sb.append(" eof:");
    sb.append(String.valueOf(_eof));
    sb.append(" [").append(super.toString()).append("]");
    return sb.toString();
  }
}