// Copyright (C) 1999-2005 Open Source Telecom Corporation.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.
//
// This exception applies only to the code released under the name GNU
// Common C++.  If you copy code from other releases into a copy of GNU
// Common C++, as the General Public License permits, the exception does
// not apply to the code that you add in this way.  To avoid misleading
// anyone as to the status of such modified files, you must delete
// this exception notice from them.
//
// If you write modifications of your own for GNU Common C++, it is your choice
// whether to permit this exception to apply to your modifications.
// If you do not wish that, delete this exception notice.
//

/**
 * @file socketport.h
 * @short Network service framework and design pattern.
 **/

#ifndef	CCXX_SOCKETPORT_H_
#define	CCXX_SOCKETPORT_H_

#ifndef	CCXX_ADDRESS_H_
#include <cc++/address.h>
#endif

#ifndef	CCXX_SOCKET_H_
#include <cc++/socket.h>
#endif

#ifdef	CCXX_NAMESPACES
namespace ost {
#endif

class __EXPORT SocketPort;
class __EXPORT SocketService;

/**
 * The socket port is an internal class which is attached to and then
 * serviced by a specific SocketService "object".  Derived versions of
 * this class offer specific functionality for specific protocols.  Both
 * Common C++ supporting frameworks and application objects may be derived
 * from related protocol specific base classes.
 *
 * A special set of classes, "SocketPort" and "SocketService", exist
 * for building realtime streaming media servers on top of UDP and TCP
 * protocols.  The "SocketPort" is used to hold a connected or associated TCP
 * or UDP socket which is being "streamed" and which offers callback methods
 * that are invoked from a "SocketService" thread.  SocketService's can be
 * pooled into logical thread pools that can service a group of SocketPorts.
 * A millisecond accurate "timer" is associated with each SocketPort and can
 * be used to time synchronize SocketPort I/O operations.
 *
 * @author David Sugar <dyfet@ostel.com>
 * @short base class for realtime and thread pool serviced protocols.
 */
class __EXPORT SocketPort : public Socket, public TimerPort
{
private:
	SocketPort *next, *prev;
	SocketService *service;
#ifndef WIN32
	struct timeval porttimer;
#ifdef USE_POLL
	struct pollfd	* ufd;
#endif
#else
	HANDLE event;
#endif
	bool detect_pending;
	bool detect_output;
	bool detect_disconnect;

	friend class SocketService;

protected:
	/**
	 * Construct an accepted TCP socket connection from a specific
	 * bound TCP server.  This is meant to derive advanced application
	 * specific TCP servers that can be thread pooled.
	 *
	 * @param svc pool thread object.
	 * @param tcp socket object to accept.
	 */
	SocketPort(SocketService *svc, TCPSocket &tcp);
#ifdef	CCXX_IPV6
	SocketPort(SocketService *svc, TCPV6Socket &tcp);
#endif

	/**
	 * Construct a bound UDP socket for use in deriving realtime
	 * UDP streaming protocols handled by thread pool objects.
	 *
	 * @param svc pool thread object.
	 * @param ia address of interface to bind.
	 * @param port number to bind to.
	 */
	SocketPort(SocketService *svc, const IPV4Address &ia, tpport_t port);
#ifdef	CCXX_IPV6
	SocketPort(SocketService *svc, const IPV6Address &ia, tpport_t port);
#endif

	/**
	 * A non-blocking constructor for outbound tcp connections.
	 * To detect when the connection is established, overload
	 * SocketPort::output().  SocketPort::output() get's called by
	 * the SocketService when the connection is ready,
	 * SocketPort::disconnect() when the connect failed.  at the
	 * moment you should set the socket state to "CONNECTED" when
	 * SocketPort::output() get's called for the first time.
	 *
	 * @param svc pool thread object.
	 * @param ih addess to connect to.
	 * @param port number to connect to.
	 **/
	SocketPort(SocketService *svc, const IPV4Host &ih, tpport_t port);
#ifdef	CCXX_IPV6
	SocketPort(SocketService *svc, const IPV6Host &ih, tpport_t port);
#endif

	/**
	 * Attach yourself to the service pool thread object. The later version.
	 *
	 * @param svc pool thread object
	 */
	 void attach( SocketService* svc );


	/**
	 * Disconnect the socket from the service thread pool and
	 * the remote connection.
	 */
	virtual ~SocketPort();

	/**
	 * Used to indicate if the service thread should monitor pending
	 * data for us.
	 */
	void setDetectPending( bool );

	/**
	 * Get the current state of the DetectPending flag.
	 */
	bool getDetectPending( void ) const
		{ return detect_pending; }

	/**
	 * Used to indicate if output ready monitoring should be performed
	 * by the service thread.
	 */
	void setDetectOutput( bool );

	/**
	 * Get the current state of the DetectOutput flag.
	 */
	bool getDetectOutput( void ) const
		{ return detect_output; }

	/**
	 * Called by the service thread pool when the objects timer
	 * has expired.  Used for timed events.
	 */
	virtual void expired(void);

	/**
	 * Called by the service thread pool when input data is pending
	 * for this socket.
	 */
	virtual void pending(void);

	/**
	 * Called by the service thread pool when output data is pending
	 * for this socket.
	 */
	virtual void output(void);

	/**
	 * Called by the service thread pool when a disconnect has
	 * occured.
	 */
	virtual void disconnect(void);

	/**
	 * Connect a Socket Port to a known peer host.  This is normally
	 * used with the UDP constructor.  This is also performed as a
	 * non-blocking operation under Posix systems to prevent delays
	 * in a callback handler.
	 *
	 * @return 0 if successful.
	 * @param ia address of remote host or subnet.
	 * @param port number of remote peer(s).
	 */
	Error connect(const IPV4Address &ia, tpport_t port);
#ifdef	CCXX_IPV6
	Error connect(const IPV6Address &ia, tpport_t port);
#endif

	/**
	 * Transmit "send" data to a connected peer host.  This is not
	 * public by default since an overriding protocol is likely to
	 * be used in a derived class.
	 *
	 * @return number of bytes sent.
	 * @param buf address of buffer to send.
	 * @param len of bytes to send.
	 */
	inline ssize_t send(const void *buf, size_t len)
		{return _IORET64 ::send(so, (const char *)buf, _IOLEN64 len, 0);};

	/**
	 * Receive a message from any host.  This is used in derived
	 * classes to build protocols.
	 *
	 * @param buf pointer to packet buffer to receive.
	 * @param len of packet buffer to receive.
	 * @return number of bytes received.
	 */
	inline ssize_t receive(void *buf, size_t len)
		{return _IORET64 ::recv(so, (char *)buf, _IOLEN64 len, 0);};

	/**
	 * Examine the content of the next packet.  This can be used
	 * to build "smart" line buffering for derived TCP classes.
	 *
	 * @param buf pointer to packet buffer to examine.
	 * @param len of packet buffer to examine.
	 * @return number of bytes actually available.
	 */
	inline ssize_t peek(void *buf, size_t len)
		{return _IORET64 ::recv(so, (char *)buf, _IOLEN64 len, MSG_PEEK);};

public:
	/**
	 * Derived setTimer to notify the service thread pool of change
	 * in expected timeout.  This allows SocketService to
	 * reschedule all timers.  Otherwise same as TimerPort.
	 *
	 * @param timeout in milliseconds.
	 */
	void setTimer(timeout_t timeout = 0);

	/**
	 * Derived incTimer to notify the service thread pool of a
	 * change in expected timeout.  This allows SocketService to
	 * reschedule all timers.  Otherwise same as TimerPort.
	 *
	 * @param timeout in milliseconds.
	 */
	void incTimer(timeout_t timeout);
};

/**
 * The SocketService is a thread pool object that is meant to service
 * attached socket ports.  Multiple pool objects may be created and
 * multiple socket ports may be attached to the same thread of execution.
 * This allows one to balance threads and sockets they service rather than
 * either using a single thread for all connections or a seperate thread
 * for each connection.  Features can be added through supported virtual
 * methods.
 *
 * @author David Sugar <dyfet@ostel.com>
 * @short Thread pool service object for socket ports.
 */
class __EXPORT SocketService : public Thread, private Mutex
{
private:
#ifndef WIN32
	fd_set connect;
	int iosync[2];
	int hiwater;
#else
	// private syncronization class
	class Sync;
	Sync* sync;
#endif
	int volatile count;
	SocketPort* volatile first, *last;

	/**
	 * Attach a new socket port to this service thread.
	 *
	 * @param port of SocketPort derived object to attach.
	 */
	void attach(SocketPort *port);
	/**
	 * Detach a socket port from this service thread.
	 *
	 * @param port of SocketPort derived object to remove.
	 */
	void detach(SocketPort *port);

	/**
	 * The service thread itself.
	 */
	void run(void);

	friend class SocketPort;

protected:
	/**
	 * Handles all requests other than "termination".
	 *
	 * @param buf request id as posted from update().
	 */
	virtual void onUpdate(unsigned char buf);

	/**
	 * Called once each time the service thread is rescheduled.
	 * This is called after the mutex is locked and can be used to
	 * slip in additional processing.
	 */
	virtual void onEvent(void);

	/**
	 * Called for each port that is being processed in response to
	 * an event.  This can be used to add additional notification
	 * options during callback in combination with update().
	 *
	 * @param port SocketPort who's callback events are being evaluated.
	 */
	virtual void onCallback(SocketPort *port);

public:
	/**
	 * Notify service thread that a port has been added or
	 * removed, or a timer changed, so that a new schedule
	 * can be computed for expiring attached ports.  A "0"
	 * is used to terminate the service thread, and additional
	 * values can be specified which will be "caught" in the
	 * onUpdate() handler.
	 *
	 * @param flag update flag value.
	 */
	void update(unsigned char flag = 0xff);

	/**
	 * Create a service thread for attaching socket ports.  The
	 * thread begins execution with the first attached socket.
	 *
	 * @param pri of this thread to run under.
	 * @param stack stack size.
	 * @param id thread ID.
	 */
	SocketService(int pri = 0, size_t stack = 0, const char *id = NULL);

	/**
	 * Terminate the thread pool and eliminate any attached
	 * socket ports.
	 */
	virtual ~SocketService();

	/**
	 * Get current reference count.  This can be used when selecting
	 * the least used service handler from a pool.
	 *
	 * @return count of active ports.
	 */
	inline int getCount(void) const
		{return count;};
};

#ifdef	CCXX_NAMESPACES
}
#endif

#endif
/** EMACS **
 * Local variables:
 * mode: c++
 * c-basic-offset: 8
 * End:
 */