NfsReaddirplusRequest.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.Credential;
import com.emc.ecs.nfsclient.rpc.Xdr;
import java.io.FileNotFoundException;

/**
 * The request, as specified by RFC 1813 (https://tools.ietf.org/html/rfc1813).
 *
 * <p>Procedure READDIRPLUS retrieves a variable number of entries from a file system directory and
 * returns complete information about each along with information to allow the client to request
 * additional directory entries in a subsequent READDIRPLUS. READDIRPLUS differs from READDIR only
 * in the amount of information returned for each entry. In READDIR, each entry returns the filename
 * and the fileid. In READDIRPLUS, each entry returns the name, the fileid, attributes (including
 * the fileid), and file handle.
 *
 * @author seibed
 */
public class NfsReaddirplusRequest extends NfsRequestBase {

  /**
   * This should be set to 0 in the first request to read the directory. On subsequent requests, it
   * should be a <code>cookie</code> as returned by the server.
   */
  private final long _cookie;

  /**
   * This should be set to 0 in the first request to read the directory. On subsequent requests, it
   * should be a <code>cookieverf</code> as returned by the server. The <code>cookieverf</code> must
   * match that returned by the READDIRPLUS in which the <code>cookie</code> was acquired.
   */
  private final long _cookieverf;

  /**
   * The maximum number of bytes of directory information returned. This number should not include
   * the size of the attributes and file handle portions of the result.
   */
  private final int _dircount;

  /**
   * The maximum size of the READDIRPLU3resok structure, in bytes. The size must include all XDR
   * overhead. The server is free to return less than <code>maxcount</code> bytes of data.
   */
  private final int _maxcount;

  /**
   * Creates the request, as specified by RFC 1813 (https://tools.ietf.org/html/rfc1813).
   *
   * <p>Procedure READDIRPLUS retrieves a variable number of entries from a file system directory
   * and returns complete information about each along with information to allow the client to
   * request additional directory entries in a subsequent READDIRPLUS. READDIRPLUS differs from
   * READDIR only in the amount of information returned for each entry. In READDIR, each entry
   * returns the filename and the fileid. In READDIRPLUS, each entry returns the name, the fileid,
   * attributes (including the fileid), and file handle.
   *
   * @param fileHandle The file handle for the directory to be read.
   * @param cookie This should be set to 0 in the first request to read the directory. On subsequent
   *     requests, it should be a <code>cookie</code> as returned by the server.
   * @param cookieverf This should be set to 0 in the first request to read the directory. On
   *     subsequent requests, it should be a <code>cookieverf</code> as returned by the server. The
   *     <code>cookieverf</code> must match that returned by the READDIRPLUS in which the <code>
   *     cookie</code> was acquired.
   * @param dircount The maximum number of bytes of directory information returned. This number
   *     should not include the size of the attributes and file handle portions of the result.
   * @param maxcount The maximum size of the READDIRPLUS3resok structure, in bytes. The size must
   *     include all XDR overhead. The server is free to return less than <code>maxcount</code>
   *     bytes of data.
   * @param credential The credential used for RPC authentication.
   * @param nfsVersion The NFS version number
   */
  public NfsReaddirplusRequest(
      byte[] fileHandle,
      long cookie,
      long cookieverf,
      int dircount,
      int maxcount,
      Credential credential,
      int nfsVersion)
      throws FileNotFoundException {
    super(Nfs.RPC_PROGRAM, nfsVersion, Nfs.NFSPROC3_READDIRPLUS, credential, fileHandle);
    _cookie = cookie;
    _cookieverf = cookieverf;
    _dircount = dircount;
    _maxcount = maxcount;
  }

  /** {@inheritDoc} */
  @Override
  public void marshalling(Xdr xdr) {
    super.marshalling(xdr);
    xdr.putLong(_cookie);
    xdr.putLong(_cookieverf);
    xdr.putUnsignedInt(_dircount);
    xdr.putUnsignedInt(_maxcount);
  }

  /** {@inheritDoc} */
  @Override
  public String toString() {
    return startToString("NfsReaddirplusRequest")
        .append(" cookie:")
        .append(String.valueOf(_cookie))
        .append(" cookieverf")
        .append(String.valueOf(_cookieverf))
        .toString();
  }
}