/*
 * Copyright (c) 2000, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package com.sun.jndi.ldap.ctl;

import java.io.IOException;
import javax.naming.ldap.BasicControl;
import com.sun.jndi.ldap.Ber;
import com.sun.jndi.ldap.BerEncoder;

/**
 * This class implements the LDAPv3 Request Control for directory
 * synchronization as defined in <tt>draft-armijo-ldap-dirsync-01.txt</tt>
 *
 * The control's value has the following ASN.1 definition:
 * <pre>
 *
 *     realReplControlValue ::= SEQUENCE {
 *         parentsFirst     INTEGER,
 *         maxReturnlength  INTEGER,
 *         cookie           OCTET STRING }
 *
 * </pre>
 *
 * @see DirSyncResponseControl
 * @author Vincent Ryan
 */
final public class DirSyncControl extends BasicControl {

    /**
     * The dir-sync control's assigned object identifier
     * is 1.2.840.113556.1.4.841.
     */
    public static final String OID = "1.2.840.113556.1.4.841";

    /**
     * Parent entries are returned before their children when value is set to 1.
     *
     * @serial
     */
    private int parentsFirst = 1;

    /**
     * The maximum length (in bytes) to be returned in a control response.
     * Must be greater than zero for any data to be returned.
     *
     * @serial
     */
    private int maxReturnLength = Integer.MAX_VALUE;

    /**
     * A server-generated cookie.
     *
     * @serial
     */
    private byte[] cookie = new byte[0];

    private static final long serialVersionUID = 564423657960860475L;

    /**
     * Constructs a dir-sync control.
     *
     * @exception IOException If a BER encoding error occurs.
     */
    public DirSyncControl() throws IOException {
        super(OID, true, null);
        super.value = setEncodedValue();
    }

    /**
     * Constructs a dir-sync control.
     *
     * @param    criticality  The control's criticality setting.
     * @exception IOException If a BER encoding error occurs.
     */
    public DirSyncControl(boolean criticality) throws IOException {

        super(OID, criticality, null);
        super.value = setEncodedValue();
    }

    /**
     * Constructs a dir-sync control.
     *
     * @param parentsFirst Parent entries are returned before their
     *            children when value is set to 1.
     * @param maxReturnLength The maximum length (in bytes) to be returned
     *            in a control response. Must be greater than
     *            zero for any data to be returned.
     * @param cookie A server-generated cookie.
     * @param criticality The control's criticality setting.
     * @exception IOException If a BER encoding error occurs.
     */
    public DirSyncControl(int parentsFirst, int maxReturnLength,
        byte[] cookie, boolean criticality) throws IOException {

        super(OID, criticality, null);

        this.parentsFirst = parentsFirst;
        this.maxReturnLength = maxReturnLength;
        this.cookie = cookie;
        super.value = setEncodedValue();
    }

    /**
     * Sets the ASN.1 BER encoded value of the dir-sync control.
     * The result is the raw BER bytes including the tag and length of
     * the control's value. It does not include the controls OID or criticality.
     *
     * @return A possibly null byte array representing the ASN.1 BER encoded
     *         value of the LDAP dir-sync control.
     * @exception IOException If a BER encoding error occurs.
     */
    private byte[] setEncodedValue() throws IOException {

        // build the ASN.1 encoding
        BerEncoder ber = new BerEncoder(64);

        ber.beginSeq(Ber.ASN_SEQUENCE | Ber.ASN_CONSTRUCTOR);
        ber.encodeInt(parentsFirst);
        ber.encodeInt(maxReturnLength);
        ber.encodeOctetString(cookie, Ber.ASN_OCTET_STR);
        ber.endSeq();

        return ber.getTrimmedBuf();
    }
}