/*

 * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package com.sun.jndi.ldap;

import java.io.IOException;

import java.util.concurrent.BlockingQueue;

import java.util.concurrent.LinkedBlockingQueue;

import javax.naming.CommunicationException;

import javax.naming.NamingException;

import java.util.concurrent.TimeUnit;

final class LdapRequest {

    private final static BerDecoder EOF = new BerDecoder(new byte[]{}, -1, 0);

    private final static String CLOSE_MSG = "LDAP connection has been closed";

    private final static String TIMEOUT_MSG_FMT = "LDAP response read timed out, timeout used: %d ms.";

    LdapRequest next;   // Set/read in synchronized Connection methods

    final int msgId;          // read-only

    private final BlockingQueue<BerDecoder> replies;

    private volatile boolean cancelled;

    private volatile boolean closed;

    private volatile boolean completed;

    private final boolean pauseAfterReceipt;

    LdapRequest(int msgId, boolean pause, int replyQueueCapacity) {

        this.msgId = msgId;

        this.pauseAfterReceipt = pause;

        if (replyQueueCapacity == -1) {

            this.replies = new LinkedBlockingQueue<>();

        } else {

            this.replies = new LinkedBlockingQueue<>(8 * replyQueueCapacity / 10);

        }

    }

    void cancel() {

        cancelled = true;

        replies.offer(EOF);

    }

    synchronized void close() {

        closed = true;

        replies.offer(EOF);

    }

    private boolean isClosed() {

        return closed && (replies.size() == 0 || replies.peek() == EOF);

    }

    synchronized boolean addReplyBer(BerDecoder ber) {

        // check the closed boolean value here as we don't want anything

        // to be added to the queue after close() has been called.

        if (cancelled || closed) {

            return false;

        }

        // peek at the BER buffer to check if it is a SearchResultDone PDU

        try {

            ber.parseSeq(null);

            ber.parseInt();

            completed = (ber.peekByte() == LdapClient.LDAP_REP_RESULT);

        } catch (IOException e) {

            // ignore

        }

        ber.reset();

        // Add a new reply to the queue of unprocessed replies.

        try {

            replies.put(ber);

        } catch (InterruptedException e) {

            // ignore

        }

        return pauseAfterReceipt;

    }

    /**

     * Read reply BER

     * @param millis timeout, infinite if the value is negative

     * @return BerDecoder if reply was read successfully

     * @throws CommunicationException request has been canceled and request does not need to be abandoned

     * @throws NamingException request has been closed or timed out. Request does need to be abandoned

     * @throws InterruptedException LDAP operation has been interrupted

     */

    BerDecoder getReplyBer(long millis) throws NamingException,

                                               InterruptedException {

        if (cancelled) {

            throw new CommunicationException("Request: " + msgId +

                " cancelled");

        }

        if (isClosed()) {

            throw new NamingException(CLOSE_MSG);

        }

        BerDecoder result = millis > 0 ?

                replies.poll(millis, TimeUnit.MILLISECONDS) : replies.take();

        if (cancelled) {

            throw new CommunicationException("Request: " + msgId +

                " cancelled");

        }

        // poll from 'replies' blocking queue ended-up with timeout

        if (result == null) {

            throw new NamingException(String.format(TIMEOUT_MSG_FMT, millis));

        }

        // Unexpected EOF can be caused by connection closure or cancellation

        if (result == EOF) {

            throw new NamingException(CLOSE_MSG);

        }

        return result;

    }

    boolean hasSearchCompleted() {

        return completed;

    }

}