/*
    * ====================================================================
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.http.impl.nio.client;
  
  import java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.http.ConnectionReuseStrategy;
  import org.apache.http.HttpException;
  import org.apache.http.HttpHost;
  import org.apache.http.HttpRequest;
  import org.apache.http.HttpResponse;
  import org.apache.http.client.methods.HttpExecutionAware;
  import org.apache.http.client.protocol.HttpClientContext;
  import org.apache.http.concurrent.BasicFuture;
  import org.apache.http.conn.ConnectionKeepAliveStrategy;
  import org.apache.http.nio.ContentDecoder;
  import org.apache.http.nio.ContentEncoder;
  import org.apache.http.nio.IOControl;
  import org.apache.http.nio.NHttpClientConnection;
  import org.apache.http.nio.conn.NHttpClientConnectionManager;
  import org.apache.http.nio.protocol.HttpAsyncRequestProducer;
  import org.apache.http.nio.protocol.HttpAsyncResponseConsumer;
  
  /**
   * Default implementation of {@link org.apache.http.nio.protocol.HttpAsyncClientExchangeHandler}.
   * <p>
   * Instances of this class are expected to be accessed by one thread at a time only.
   * The {@link #cancel()} method can be called concurrently by multiple threads.
   */
  class DefaultClientExchangeHandlerImpl<T> extends AbstractClientExchangeHandler {
  
      private final HttpAsyncRequestProducer requestProducer;
      private final HttpAsyncResponseConsumer<T> responseConsumer;
      private final BasicFuture<T> resultFuture;
      private final InternalClientExec exec;
      private final InternalState state;
  
      public DefaultClientExchangeHandlerImpl(
              final Log log,
              final HttpAsyncRequestProducer requestProducer,
              final HttpAsyncResponseConsumer<T> responseConsumer,
              final HttpClientContext localContext,
              final BasicFuture<T> resultFuture,
              final NHttpClientConnectionManager connmgr,
              final ConnectionReuseStrategy connReuseStrategy,
              final ConnectionKeepAliveStrategy keepaliveStrategy,
              final InternalClientExec exec) {
          super(log, localContext, connmgr, connReuseStrategy, keepaliveStrategy);
          this.requestProducer = requestProducer;
          this.responseConsumer = responseConsumer;
          this.resultFuture = resultFuture;
          this.exec = exec;
          this.state = new InternalState(getId(), requestProducer, responseConsumer, localContext);
      }
  
      @Override
      void releaseResources() {
          try {
              this.requestProducer.close();
          } catch (final IOException ex) {
              this.log.debug("I/O error closing request producer", ex);
          }
          try {
              this.responseConsumer.close();
          } catch (final IOException ex) {
              this.log.debug("I/O error closing response consumer", ex);
          }
      }
  
      @Override
      void executionFailed(final Exception ex) {
          try {
              this.requestProducer.failed(ex);
              this.responseConsumer.failed(ex);
         } finally {
             this.resultFuture.failed(ex);
         }
     }
 
     @Override
     boolean executionCancelled() {
         final boolean cancelled = this.responseConsumer.cancel();
 
         final T result = this.responseConsumer.getResult();
         final Exception ex = this.responseConsumer.getException();
         if (ex != null) {
             this.resultFuture.failed(ex);
         } else if (result != null) {
             this.resultFuture.completed(result);
         } else {
             this.resultFuture.cancel();
         }
         return cancelled;
     }
 
     @Override
     public void start() throws HttpException, IOException {
         final HttpHost target = this.requestProducer.getTarget();
         final HttpRequest original = this.requestProducer.generateRequest();
 
         if (original instanceof HttpExecutionAware) {
             ((HttpExecutionAware) original).setCancellable(this);
         }
         this.exec.prepare(target, original, this.state, this);
         requestConnection();
     }
 
     @Override
     public HttpRequest generateRequest() throws IOException, HttpException {
         return this.exec.generateRequest(this.state, this);
     }
 
     @Override
     public void produceContent(
             final ContentEncoder encoder, final IOControl ioControl) throws IOException {
         this.exec.produceContent(this.state, encoder, ioControl);
     }
 
     @Override
     public void requestCompleted() {
         this.exec.requestCompleted(this.state, this);
     }
 
     @Override
     public void responseReceived(
             final HttpResponse response) throws IOException, HttpException {
         this.exec.responseReceived(response, this.state, this);
     }
 
     @Override
     public void consumeContent(
             final ContentDecoder decoder, final IOControl ioControl) throws IOException {
         this.exec.consumeContent(this.state, decoder, ioControl);
         if (!decoder.isCompleted() && this.responseConsumer.isDone()) {
             markConnectionNonReusable();
             try {
                 markCompleted();
                 releaseConnection();
                 this.resultFuture.cancel();
             } finally {
                 close();
             }
         }
     }
 
     @Override
     public void responseCompleted() throws IOException, HttpException {
         this.exec.responseCompleted(this.state, this);
 
         if (this.state.getFinalResponse() != null || this.resultFuture.isDone()) {
             try {
                 markCompleted();
                 releaseConnection();
                 final T result = this.responseConsumer.getResult();
                 final Exception ex = this.responseConsumer.getException();
                 if (ex == null) {
                     this.resultFuture.completed(result);
                 } else {
                     this.resultFuture.failed(ex);
                 }
             } finally {
                 close();
             }
         } else {
             NHttpClientConnection localConn = getConnection();
             if (localConn != null && !localConn.isOpen()) {
                 releaseConnection();
                 localConn = null;
             }
             if (localConn != null) {
                 localConn.requestOutput();
             } else {
                 requestConnection();
             }
         }
     }
 
     @Override
     public void inputTerminated() {
         if (!isCompleted()) {
             requestConnection();
         } else {
             close();
         }
     }
 
     public void abortConnection() {
         discardConnection();
     }
 
 }