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/**
 * Copyright (c) 2013-2021 Nikita Koksharov
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License 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 org.redisson.pubsub;

import org.redisson.PubSubEntry;
import org.redisson.api.RFuture;
import org.redisson.client.BaseRedisPubSubListener;
import org.redisson.client.ChannelName;
import org.redisson.client.RedisPubSubListener;
import org.redisson.client.codec.LongCodec;
import org.redisson.client.protocol.pubsub.PubSubType;
import org.redisson.misc.RPromise;
import org.redisson.misc.RedissonPromise;
import org.redisson.misc.TransferListener;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * 
 * @author Nikita Koksharov
 *
 */
abstract class PublishSubscribe> {

    private final ConcurrentMap entries = new ConcurrentHashMap<>();
    private final PublishSubscribeService service;

    PublishSubscribe(PublishSubscribeService service) {
        super();
        this.service = service;
    }

    public void unsubscribe(E entry, String entryName, String channelName) {
        AsyncSemaphore semaphore = service.getSemaphore(new ChannelName(channelName));
        semaphore.acquire(() -> {
            if (entry.release() == 0) {
                // just an assertion
                boolean removed = entries.remove(entryName) == entry;
                if (!removed) {
                    throw new IllegalStateException();
                }
                service.unsubscribe(PubSubType.UNSUBSCRIBE, new ChannelName(channelName))
                        .onComplete((r, e) -> {
                            semaphore.release();
                        });
            } else {
                semaphore.release();
            }
        });

    }

    public RFuture subscribe(String entryName, String channelName) {
        AsyncSemaphore semaphore = service.getSemaphore(new ChannelName(channelName));
        RPromise newPromise = new RedissonPromise<>();
        semaphore.acquire(() -> {
            if (!newPromise.setUncancellable()) {
                semaphore.release();
                return;
            }

            E entry = entries.get(entryName);
            if (entry != null) {
                entry.acquire();
                semaphore.release();
                entry.getPromise().onComplete(new TransferListener(newPromise));
                return;
            }

            E value = createEntry(newPromise);
            value.acquire();

            E oldValue = entries.putIfAbsent(entryName, value);
            if (oldValue != null) {
                oldValue.acquire();
                semaphore.release();
                oldValue.getPromise().onComplete(new TransferListener(newPromise));
                return;
            }

            RedisPubSubListener