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<TITLE>Access Scheme Manager</TITLE>
<!-- Changed by: Henrik Frystyk Nielsen,  9-Jul-1995 -->
<NEXTID N="z11">
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<H1>Access Scheme Manager</H1>

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

This module keeps a list of valid protocol (naming scheme) specifiers
with associated access code. New access protocols may be registered at
any time.<P>

This module is implemented by <A HREF="HTProt.c">HTProt.c</A>, and it
is a part of the <A NAME="z10"
HREF="http://www.w3.org/pub/WWW/Library/">
W3C Reference Library</A>. <P>

<PRE>
#ifndef HTPROT_H
#define HTPROT_H

#include "HTAccess.h"
#include "HTAnchor.h"
</PRE>

An access scheme is defined by an HTProtocol structure which point to
the routines for performing the various logical operations on an
object: in HTTP terms, GET, PUT, and POST. The access schemes
supported in the Library are initiated automaticly using the function
<CODE>HTAccessInit()</CODE> <B>if not</B> defined
<CODE>HT_NO_INIT</CODE> <P>

Each of these routine takes as a parameter a <A NAME="z2"
HREF="HTAccess.html#z1">request structure</A> containing details of
the request.  When the protocol class routine is called, the anchor
element in the request is already valid (made valid by HTAccess).

<PRE>
typedef enum _HTSocBlock {
    SOC_BLOCK,
    SOC_NON_BLOCK
} HTSocBlock;

typedef struct _HTProtocol {
    char *	name;
    HTSocBlock	block;	
    int		(*load)		PARAMS((HTRequest *	request));
    HTStream*	(*saveStream)	PARAMS((HTRequest *	request));
    HTStream* 	(*postStream)	PARAMS((HTRequest *	request,
					HTParentAnchor* postTo));
} HTProtocol;
</PRE>

<H3>Add an Access Scheme</H3>

This functions registers a protocol module and binds it to a specific
access acheme. For example HTTP.c is bound to http URLs.

<PRE>
extern BOOL HTProtocol_add		PARAMS((HTProtocol * protocol));
</PRE>

<H3>Get an Access Scheme</H3>

This function finds the access scheme that is bound to the anchor's
type of URL. Returns YES if found, else NO

<PRE>
extern BOOL HTProtocol_get		PARAMS((HTParentAnchor * anchor));
</PRE>

<H3>Remove ALL Registered Schemes</H3>

This is the garbage collection function. It is called by <A
HREF="HTAccess.html#Library">HTLibTerminate</A>

<PRE>
extern void HTProtocol_deleteAll	NOPARAMS;
</PRE>

<H3>Is the Scheme using Blocking I/O?</H3>

A small function to make life easier. Returns <CODE>YES</CODE> or
<CODE>NO</CODE>. If the Library is run in non-interactive mode then
the function always returns YES;

<PRE>
#define HTProtocol_isBlocking(me) \
	((me) &amp;&amp; ((me)->BlockingIO || \
		((me)->anchor &amp;&amp; (me)->anchor->protocol &amp;&amp; \
			((HTProtocol*)((me)->anchor->protocol))->block==SOC_BLOCK)))
</PRE>

<PRE>
#endif /* HTPROT_H */
</PRE>

End of Declaration

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