/*                                             W3C Sample Code Library libwww Transport Class
                                   THE TRANSPORT CLASS
                                             
 */
/*
**      (c) COPYRIGHT MIT 1995.
**      Please first read the full copyright statement in the file COPYRIGH.
*/
/*

   The Transport Class defines a transport as used by the HTChannel class to communicate
   with the network, the local file system etc. New transport objects may be registered at
   any time. This allows the application to easily hook in its own transport layers. The
   purpose of the HTTransport object is to contain transport dependent methods for opening
   and closing a connection to the transport and also to get an input stream and an output
   strean for reading and writing to the transport respectively.
   
   _Note_: The library _core_ does not  define any default transport objects - they are
   all considered part of the application. The library comes with a default set of
   transports which can be initiated using the function HTTransportInit()in HTInit module
   
   This module is implemented by HTTrans.c, and it is a part of the W3C Sample Code
   Library.
   
 */
#ifndef HTTRANS_H
#define HTTRANS_H
/*

CREATION AND DELETION METHODS

   All transport interfaces are registered dynamically in libwww. This means that libwww
   is independent of the transport being used (for example TCP) and you can therefore use
   libwww in any context you like. You have to specify a set of parameters in order for
   libwww to be able to use it. The transport class is defined as follows:
   
 */
typedef struct _HTTransport HTTransport;

typedef enum _HTTransportMode {
    HT_TP_SINGLE        = 0,            /* One single request at a time */
    HT_TP_PIPELINE      = 1,            /* Use pipelined requests */
    HT_TP_INTERLEAVE    = 2             /* Can we interleave requests? */
} HTTransportMode;

#include "HTIOStream.h"
#include "HTReq.h"
/*

  Add a Transport
  
   A new transport can be registered at any time in the Library. You must specify a name
   ad the supported channel mode that the transport supports. Then you must also register
   two creation methods of an input and an output stream respectively. You can find the
   definition of the I/O streams in the HTIOStream module.
   
 */
extern BOOL HTTransport_add (const char *               name,
                             HTTransportMode            mode,
                             HTInput_new *              get_input,
                             HTOutput_new *             get_output);
/*

  Delete a Transport
  
   This functions deletes a registered protocol module so that it can not be used for
   accessing a resource anymore.
   
 */
extern BOOL HTTransport_delete (const char * name);
/*

  Remove ALL Registered Transports
  
   This is the garbage collection function. It is called by HTLibTerminate()
   
 */
extern BOOL HTTransport_deleteAll (void);
/*

TRANSPORT CLASS METHODS

  Find a Transport Protocol Object
  
   You can search the list of registered protocol objects as a function of the access
   acheme. If an access scheme is found then the protocol object is returned.
   
 */
extern HTTransport * HTTransport_find (HTRequest * request, const char * name);
/*

  Supported Transort Modes
  
   A transport object is registered with the flow control mode that it supports. This mode
   describes whether we can issue multiple requests at the same time.
   
 */
extern HTTransportMode HTTransport_mode (HTTransport * tp);
extern BOOL HTTransport_setMode (HTTransport * tp, HTTransportMode mode);
/*

  Input and Output Stream Creation Methods
  
 */
struct _HTTransport {
    char *              name;
    HTTransportMode     mode;                         /* Flow mode supported */
    HTInput_new *       input_new;           /* Input stream creation method */
    HTOutput_new *      output_new;         /* Output stream creation method */
};
/*

 */
#endif /* HTTRANS_H */
/*

   
   ___________________________________
   
                            @(#) $Id: HTTrans.html,v 2.6 1997/02/16 18:43:10 frystyk Exp $
                                                                                          
    */