content: /*
   * Copyright 2021-2024 Aklivity Inc.
   *
   * Aklivity 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.
   */
  package io.aklivity.zilla.runtime.engine.internal.poller;
  
  import static org.agrona.CloseHelper.quietClose;
  
  import java.nio.channels.ClosedChannelException;
  import java.nio.channels.SelectableChannel;
  import java.nio.channels.SelectionKey;
  import java.util.function.Consumer;
  import java.util.stream.Stream;
  
  import org.agrona.LangUtil;
  import org.agrona.nio.TransportPoller;
  
  public final class Poller extends TransportPoller
  {
      private final Consumer<SelectionKey> selectHandler;
  
      public Poller()
      {
          this.selectHandler = this::handleSelect;
      }
  
      public int doWork()
      {
          int workDone = 0;
  
          try
          {
              workDone += selector.selectNow(selectHandler);
          }
          catch (Throwable ex)
          {
              LangUtil.rethrowUnchecked(ex);
          }
  
          return workDone;
      }
  
      public void onClose()
      {
          for (SelectionKey key : selector.keys())
          {
              quietClose(key.channel());
          }
  
          // Allow proper cleanup on platforms like Windows
          selectNowWithoutProcessing();
  
          super.close();
      }
  
      public PollerKeyImpl register(
          SelectableChannel channel)
      {
          PollerKeyImpl pollerKey = null;
  
          try
          {
              SelectionKey key = channel.keyFor(selector);
              if (key == null)
              {
                  key = channel.register(selector, 0, null);
                  key.attach(new PollerKeyImpl(key));
              }
  
              pollerKey = attachment(key);
          }
          catch (ClosedChannelException ex)
          {
              LangUtil.rethrowUnchecked(ex);
          }
  
          return pollerKey;
      }
  
      public Stream<PollerKeyImpl> keys()
      {
          return selector.keys().stream().map(k -> attachment(k));
      }
  
      private int handleSelect(
          SelectionKey key)
      {
          final PollerKeyImpl attachment = attachment(key);
          return attachment.handleSelect(key);
      }
  
      private static PollerKeyImpl attachment(
          SelectionKey key)
      {
          return (PollerKeyImpl) key.attachment();
      }
  }
  