NfsWriteResponse.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;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

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

  private static final Logger _log = LoggerFactory.getLogger(NfsWriteResponse.class);

  /**
   * One of the values below.
   *
   * <ul>
   *   <li>UNSTABLE = 0 - Best effort was made, no promises.
   *   <li>DATA_SYNC = 1 - Committed all data to stable storage, plus enough metadata for retrieval,
   *       before returning.
   *   <li>FILE_SYNC = 2 - Committed all data and metadata to stable storage before returning.
   * </ul>
   */
  private int _committed;

  /**
   * The number of bytes of data written to the file. The server may write fewer bytes than
   * requested. If so, the actual number of bytes written starting at location, <code>offset</code>,
   * is returned.
   */
  private int _count;

  /** Weak cache consistency data for the file. */
  private NfsWccData _fileWccData = new NfsWccData();

  /**
   * This is a cookie that the client can use to determine whether the server has changed state
   * between a call to WRITE and a subsequent call to either WRITE or COMMIT. This cookie must be
   * consistent during a single instance of the NFS version 3 protocol service and must be unique
   * between instances of the NFS version 3 protocol server, where uncommitted data may be lost.
   */
  private long _verf;

  /**
   * Creates the response, as specified by RFC 1813 (https://tools.ietf.org/html/rfc1813).
   *
   * <p>Procedure WRITE writes data to a file.
   *
   * @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 NfsWriteResponse(int nfsVersion) {
    super();
  }

  /** {@inheritDoc} */
  @Override
  public void unmarshalling(Xdr xdr) throws RpcException {
    super.unmarshalling(xdr);
    _fileWccData = new NfsWccData(xdr);
    if (stateIsOk()) {
      _count = xdr.getInt();
      _committed = xdr.getInt();
      _verf = xdr.getLong();
      _log.trace("committed {} verf {}", _committed, _verf);
    }
  }

  /**
   * Returns one of the values below.
   *
   * <ul>
   *   <li>UNSTABLE = 0 - Best effort was made, no promises.
   *   <li>DATA_SYNC = 1 - Committed all data to stable storage, plus enough metadata for retrieval,
   *       before returning.
   *   <li>FILE_SYNC = 2 - Committed all data and metadata to stable storage before returning.
   * </ul>
   *
   * .
   */
  public int getCommitted() {
    return _committed;
  }

  /**
   * Returns the number of bytes of data written to the file. The server may write fewer bytes than
   * requested. If so, the actual number of bytes written starting at location, <code>offset
   * </code>, is returned.
   */
  public int getCount() {
    return _count;
  }

  /** Returns weak cache consistency data for the file. */
  public NfsWccData getFileWccData() {
    return _fileWccData;
  }

  /**
   * Returns this is a cookie that the client can use to determine whether the server has changed
   * state between a call to WRITE and a subsequent call to either WRITE or COMMIT. This cookie must
   * be consistent during a single instance of the NFS version 3 protocol service and must be unique
   * between instances of the NFS version 3 protocol server, where uncommitted data may be lost.
   */
  public long getVerf() {
    return _verf;
  }
}