content: /*
   * Copyright (C) 2020 ActiveJ LLC.
   *
   * 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 io.activej.http;
  
  import io.activej.common.Checks;
  
  import static io.activej.common.Checks.checkArgument;
  
  public final class AddressLinkedList {
  	private static final boolean CHECKS = Checks.isEnabled(AddressLinkedList.class);
  
  	private HttpClientConnection first;
  	private HttpClientConnection last;
  
  	public boolean isEmpty() {
  		return first == null;
  	}
  
  	public HttpClientConnection removeLastNode() {
  		if (last == null)
  			return null;
  		HttpClientConnection node = last;
  		last = node.addressPrev;
  		if (node.addressPrev != null) {
  			node.addressPrev.addressNext = node.addressNext;
  		} else {
  			assert first == node;
  			first = node.addressNext;
  		}
  		node.addressNext = node.addressPrev = null;
  		return node;
  	}
  
  	public void addLastNode(HttpClientConnection node) {
  		if (CHECKS) checkArgument(node.addressPrev == null && node.addressNext == null);
  		if (last != null) {
  			assert last.addressNext == null;
  			last.addressNext = node;
  			node.addressPrev = last;
  		} else {
  			assert first == null;
  			first = node;
  		}
  		last = node;
  	}
  
  	public void removeNode(HttpClientConnection node) {
  		if (node.addressPrev != null) {
  			node.addressPrev.addressNext = node.addressNext;
  		} else {
  			assert first == node;
  			first = node.addressNext;
  		}
  		if (node.addressNext != null) {
  			node.addressNext.addressPrev = node.addressPrev;
  		} else {
  			assert last == node;
  			last = node.addressPrev;
  		}
  		node.addressNext = node.addressPrev = null;
  	}
  
  	public int size() {
  		int count = 0;
  		for (HttpClientConnection connection = first; connection != null; connection = connection.addressNext) {
  			count++;
  		}
  		return count;
  	}
  }
  