EventHandler.h

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  /* Copyright 2006-2013 Savarese Software Research Corporation.
   *
   * 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.savarese.com/software/ApacheLicense-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.
   */
  
  #ifndef __SSRC_WISP_SERVICE_EVENT_HANDLER_H
  #define __SSRC_WISP_SERVICE_EVENT_HANDLER_H
  
  #include <ssrc/wisp/utility/TimeValue.h>
  
  __BEGIN_NS_SSRC_WISP_SERVICE
  
  using NS_SSRC_WISP_UTILITY::TimeValue;
  using NS_SSRC_WISP_UTILITY::InfiniteTimeValue;
  
  // Forward declaration of EventInfo.
  class EventInfo;
  
  // Currently implemented so you need one EventHandler instance per
  // descriptor. It is possible to implement this so that you can use
  // the same EventHandler instance for multiple descriptors (passing
  // the file descriptor to the handler via EventInfo), but it's only
  // a benefit for EventHandlers that need to share state between
  // descriptors or that consume a lot of memory. Right now it's
  // not a win because we still have to allocate structures that store
  // timeout info and point to handlers, so why not just use the handler?
  class EventHandler {
   friend class EventLoop;
   friend class EventLoopState;
  
   bool _handled_timeout; // scratch variable;
   bool _once;
  #if defined(WISP_HAVE_NONPERSISTENT_EVENTS) || defined(WISP_HAVE_KQUEUE)
   int _events; // store original events of interest
  #endif
   TimeValue _timeout;
   TimeValue _expiration;
  
  protected:
  
   const TimeValue & timeout() const {
   return _timeout;
   }
  
   const TimeValue & expiration() const {
   return _expiration;
   }
  
   bool has_timeout() const {
   return (_timeout < InfiniteTimeValue);
   }
  
  public:
  
   static const int NoDescriptor = -1;
  
   virtual ~EventHandler() = default;
  
   virtual int event_descriptor() const {
   return NoDescriptor;
   }
  
  #if defined(WISP_HAVE_NONPERSISTENT_EVENTS) || defined(WISP_HAVE_KQUEUE)
   int events() { return _events; }
  #endif
  
   virtual void handle_read(const EventInfo & info) { }
  
   virtual void handle_write(const EventInfo & info) { }
  
   virtual void handle_timeout(const EventInfo & info) { }
  
   //virtual void handle_signal(const EventInfo & info) { }
  
   virtual void handle_error(const EventInfo & info) { }
  
   virtual void handle_hangup(const EventInfo & info) { }
  };
  
  __END_NS_SSRC_WISP_SERVICE
  
  #endif