/*
 *	Ivy League
 *
 *	File descriptors, channels
 *
 *	Copyright 1990-2000
 *	Laboratoire de Recherche en Informatique (LRI)
 *	Centre d'Etudes de la Navigation Aerienne (CENA)
 *
 *	original code by Michel Beaudouin-Lafon,
 *	heavily modified by Stephane Chatty and Stephane Sire
 *
 *	$Id$
 *
 */

#ifndef Channel_H_
#define Channel_H_

#ifdef __GNUG__
#pragma interface
#endif

#include "cplus_bugs.h"
#include "ivl/bool.h"
#include "IOS.h"

class IvlMsgBuffer;
class IvlString;

// we need read and write system calls
#include <unistd.h>

#ifndef NFILE
#define NFILE 64
#endif

enum	IOMODE	{ IONone = 0, IORead = 1, IOWrite = 2,
			  IOReadWrite = 3, IOSelect = 4, IOReadSelect = 5,
			  IOWriteSelect = 6, IOAll = 7 };

extern	char*	StrReprBuf;

class IvlFd {
private:
static	void	Use (int);
static	void	Unuse (int);

protected:
	int	Fd;
public:
inline		IvlFd () : Fd (-1)	{ }
inline		IvlFd (const IvlFd& fd)	{ Use (Fd = fd.Fd); }
inline		IvlFd (int fd)		{ Use (Fd = fd); }
inline		~IvlFd ()			{ Unuse (Fd); }

inline	operator int ()	const			{ return Fd; }
inline	IvlFd&	operator = (const IvlFd& fd)	{ Unuse (Fd); Fd = fd.Fd; Use (Fd); return *this; }
inline	void		Open (int fd)		{ Unuse (Fd); Use (Fd = fd); }
inline	void		Close ()			{ Unuse (Fd); Fd = -1; }
inline	bool		Opened ()		{ return bool (Fd >= 0); }
inline	int		Read (byte* b, int n)	{ return read (Fd, (char*) b, n); }
inline	int		Write (byte* b, int n)	{ return write (Fd, (const char*) b, n); }
	char*		StrRepr (char* = StrReprBuf);
};

//	This class defines channels, ie file descriptors with handlers for read/write.
//	The file descriptor of a channel is immutable: once created, it cannot change;
//	this is crucial for channel sets, for instance.
//	Be careful with Copy and operator= if redefined because this can 
//	potentially bypass immutability.
//

class IvlChannel : public IvlIOS {
friend	class	IvlBaseScheduler;
protected:
	IvlFd		Fd;
	IOMODE	Mode;
	IvlBaseScheduler*	Mpx;

virtual	void	Added ();
virtual	void	Removed ();

public:
		IvlChannel ();
		IvlChannel (int, IOMODE = IOReadWrite);
		IvlChannel (const IvlChannel& ch);
		~IvlChannel ();

inline	void		Open (int fd)	{ if (Fd < 0) Fd.Open (fd); }
inline	void		Close ()		{ if (Fd.Opened ())  Fd.Close (); }
inline	IOMODE	IOMode () const			{ return Mode; }
inline	void		SetMode (IOMODE io)		{ Mode = io; }
	int		Read (IvlMsgBuffer&);
	int		Write (IvlMsgBuffer&);
	bool		ReadBuffer (IvlMsgBuffer&);
	bool		WriteBuffer (IvlMsgBuffer&);
	void		Add (IvlBaseScheduler*);
	void		Remove ();
virtual	void		HandleWrite ();
virtual	void		HandleRead ();

inline	int		GetFd () const			{ return Fd; }
inline	int		Read (byte* b, int n)	{ return read (Fd, (char*) b, n); }
inline	int		Write (const byte* b, int n)	{ return write (Fd, (const char*) b, n); }
inline			operator int ()		{ return Fd; }
inline	IvlBaseScheduler*	GetScheduler () const	{ return Mpx; }
inline	char*		StrRepr (char* s = StrReprBuf) { return Fd.StrRepr (s); }

virtual	void	WriteLong (lword);
virtual	void	WriteShort (sword);
virtual	void	WriteByte (byte);
virtual	void	WriteChar (char);
virtual	void	WriteString (const char*);
virtual	void	WriteBuf (const byte*, int);

virtual	bool	ReadLong (lword&);
virtual	bool	ReadShort (sword&);
virtual	bool	ReadByte (byte&);
virtual	bool	ReadChar (char&);
virtual	int	ReadString (char*, int);
virtual	int	ReadString (IvlString&);
virtual	bool	ReadBuf (byte*, int);
};

#endif /* Channel_H_ */