text: /*-
   * Copyright (c) 2011, 2012, 2013, 2014 Spectra Logic Corporation
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions, and the following disclaimer,
   *    without modification.
   * 2. Redistributions in binary form must reproduce at minimum a disclaimer
   *    substantially similar to the "NO WARRANTY" disclaimer below
   *    ("Disclaimer") and any redistribution must be conditioned upon
   *    including a substantially similar Disclaimer requirement for further
   *    binary redistribution.
   *
   * NO WARRANTY
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
   * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGES.
   *
   * Authors: Justin T. Gibbs     (Spectra Logic Corporation)
   *
   * $FreeBSD$
   */
  
  /**
   * \file devdctl_consumer.h
   */
  #ifndef	_DEVDCTL_CONSUMER_H_
  #define	_DEVDCTL_CONSUMER_H_
  
  /*============================ Namespace Control =============================*/
  namespace DevdCtl
  {
  
  /*=========================== Forward Declarations ===========================*/
  class Event;
  
  /*============================ Class Declarations ============================*/
  /*----------------------------- DevdCtl::Consumer ----------------------------*/
  
  /**
   */
  class Consumer
  {
  public:
  	Consumer(Event::BuildMethod *defBuilder = NULL,
  		 EventFactory::Record *regEntries = NULL,
  		 size_t numEntries = 0);
  	virtual ~Consumer();
  
  	bool Connected() const;
  
  	/**
  	 * Return file descriptor useful for client's wishing to poll(2)
  	 * for new events.
  	 */
  	int GetPollFd();
  
  	/**                                                          
           * Queue an event for deferred processing or replay.
           */ 
  	bool SaveEvent(const Event &event);
  
  	/**                                  
  	 * Reprocess any events saved via the SaveEvent() facility.   
  	 *
  	 * \param discardUnconsumed  If true, events that are not consumed
  	 *                           during replay are discarded.
  	 */                                                              
  	void ReplayUnconsumedEvents(bool discardUnconsumed);
  
  	/** Return an event, if one is available.  */
  	Event *NextEvent();
  
  	/**
  	 * Extract events and invoke each event's Process method.
  	 */
  	void ProcessEvents();
  
  	/** Discard all data pending in m_devdSockFD. */
  	void FlushEvents();
  
  	/**
  	 * Test for data pending in m_devdSockFD
  	 *
  	 * \return  True if data is pending.  Otherwise false.
  	 */
  	bool EventsPending();
  
  	/**
  	 * Open a connection to devd's unix domain socket.
  	 *
  	 * \return  True if the connection attempt is successsful.  Otherwise
  	 *          false.
  	 */
  	bool ConnectToDevd();
  
  	/**
  	 * Close a connection (if any) to devd's unix domain socket.
  	 */
  	void DisconnectFromDevd();
  
  	EventFactory GetFactory();
  
  protected:
  	/**
  	 * \brief Reads the most recent record
  	 *
  	 * On error, "" is returned, and errno will be set by the OS
  	 *
  	 * \returns      A string containing the record
  	 */
  	std::string ReadEvent();
  
  	enum {
  		/*
  		 * The maximum event size supported by libdevdctl.
  		 */
  		MAX_EVENT_SIZE = 8192,
  	};
  
  	static const char  s_devdSockPath[];
  
  	/**
  	 * File descriptor representing the unix domain socket
  	 * connection with devd.
  	 */
  	int                m_devdSockFD;
  
  	EventFactory	   m_eventFactory;
  
  	/** Queued events for replay. */
  	EventList	   m_unconsumedEvents;
  
  	/**                                                             
  	 * Flag controlling whether events can be queued.  This boolean
  	 * is set during event replay to ensure that previosuly deferred
  	 * events are not requeued and thus retained forever.
  	 */
  	bool		   m_replayingEvents;
  };
  
  //- Consumer Const Public Inline Methods ---------------------------------------
  inline bool
  Consumer::Connected() const
  {
  	return (m_devdSockFD != -1);
  }
  
  //- Consumer Public Inline Methods ---------------------------------------------
  inline int
  Consumer::GetPollFd()
  {
  	return (m_devdSockFD);
  }
  
  inline EventFactory
  Consumer::GetFactory()
  {
  	return (m_eventFactory);
  }
  
  } // namespace DevdCtl
  #endif	/* _DEVDCTL_CONSUMER_H_ */
  