Manages Read and Write to and from the Network

/*
**	(c) COPYRIGHT MIT 1995.
**	Please first read the full copyright statement in the file COPYRIGH.
*/

A channel contains information about sockets and their input and output streams. A channel represents the front end for receiving data. The definition of a channel describes how we are to read the data coming in on a socket, for example. A channel represents the first part of how to get handle incoming data in the Library:

Reading data on a channel
Defining a target for incoming data
Defining a protocol state machine that can handle the data

This module is implemented by HTChannl.c, and it is a part of the W3C Reference Library.

#ifndef HTCHANNL_H
#define HTCHANNL_H

typedef enum _HTChannelMode {
    HT_CH_SINGLE	= 0,		/* One single request at a time */
    HT_CH_BATCH		= 1,		/* Use batch requests */
    HT_CH_INTERLEAVED	= 2		/* Can we interleave requests? */
} HTChannelMode;

typedef struct _HTChannel HTChannel;

#include "HTTrans.h"
#include "HTReq.h"
#include "HTNet.h"
#include "HTIOStream.h"

The HTChannel Object

A channel can be in a certain mode which determines how it behaves. The set of modes is defined as:

Creating a Channel Object

The following methods can be used to instantiate objects of a particular channel mode:

extern HTChannel * HTChannel_new (HTNet * net, BOOL active);

Deleting a Channel Object

extern BOOL HTChannel_delete (HTChannel * channel);
extern BOOL HTCannel_deleteAll (void);

Control the Channel Mode

Set and get the mode of a channel. A channel may change mode in the middle of a connection. We also return whether the channel is active or passive.

extern HTChannelMode HTChannel_mode (HTChannel * channel, BOOL * active);

extern BOOL HTChannel_setMode (HTChannel * channel, HTChannelMode mode);

Search for a Channel

Look for a channel object if we for some reason should have lost it

extern HTChannel * HTChannel_find (SOCKET sockfd);

Is Channel Idle?

Check whether a channel is idle meaning if it is ready for a new request which depends on the mode of the channel. If the channel is idle, i.e. ready for use then return YES else NO.

extern BOOL HTChannel_idle (HTChannel * channel);

Get Socket for a Channel

extern SOCKET HTChannel_socket (HTChannel * channel);

Semaphores

Adjust the semaphore on a channel.

extern void HTChannel_upSemaphore (HTChannel * channel);
extern void HTChannel_downSemaphore (HTChannel * channel);

Create Input and Output Streams

You create the input stream and bind it to the channel using the following methods. Please read the description in the HTIOStream module on the parameters target, param, and mode. Both methods return YES if OK, else NO.

extern BOOL HTChannel_setInput (HTChannel * ch,
				HTInputStream * input, HTChannelMode mode);

extern BOOL HTChannel_setOutput (HTChannel * ch,
				 HTOutputStream * output, HTChannelMode mode);

extern HTInputStream * HTChannel_input (HTChannel * ch);
extern HTOutputStream * HTChannel_output (HTChannel * ch);

#endif /* HTCHANNL */

@(#) $Id: HTChannl.html,v 2.1 1996/04/12 17:46:13 frystyk Exp $