/*

 * xlink.c : implementation of the hyperlinks detection module

 *           This version supports both XML XLinks and HTML simple links

 *

 * See Copyright for the status of this software.

 *

 * daniel@veillard.com

 */

#define IN_LIBXML

#include "XmlEnglibxml.h"

#ifdef LIBXML_XPTR_ENABLED

#include <string.h> /* for memset() only */

#ifdef HAVE_CTYPE_H

#include <ctype.h>

#endif

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef HAVE_ZLIB_H

#include <zlib.h>

#endif

#include "Libxml2_xmlmemory.h"

#include "Libxml2_tree.h"

#include "Libxml2_parser.h"

#include "Libxml2_valid.h"

#include "Libxml2_xlink.h"

#include "Libxml2_globals.h"

#define XLINK_NAMESPACE (BAD_CAST "http://www.w3.org/1999/xlink/namespace/")

#define XHTML_NAMESPACE (BAD_CAST "http://www.w3.org/1999/xhtml/")

/****************************************************************

 *								*

 *           Default setting and related functions		*

 *								*

 ****************************************************************/

/**

 * xlinkGetDefaultHandler:

 *

 * Get the default xlink handler.

 *

 * Returns the current xlinkHandlerPtr value.

 */

xlinkHandlerPtr

xlinkGetDefaultHandler(void) {

    return(xlinkDefaultHandler);

}

/**

 * xlinkSetDefaultHandler:

 * @handler:  the new value for the xlink handler block

 *

 * Set the default xlink handlers

 */

void

xlinkSetDefaultHandler(xlinkHandlerPtr handler) {

    xlinkDefaultHandler = handler;

}

/**

 * xlinkGetDefaultDetect:

 *

 * Get the default xlink detection routine

 *

 * Returns the current function or NULL;

 */

xlinkNodeDetectFunc

xlinkGetDefaultDetect	(void) {

    return(xlinkDefaultDetect);

}

/**

 * xlinkSetDefaultDetect:

 * @func: pointer to the new detection routine.

 *

 * Set the default xlink detection routine

 */

void 

xlinkSetDefaultDetect	(xlinkNodeDetectFunc func) {

    xlinkDefaultDetect = func;

}

/****************************************************************

 *								*

 *                  The detection routines			*

 *								*

 ****************************************************************/

/**

 * xlinkIsLink:

 * @doc:  the document containing the node

 * @node:  the node pointer itself

 *

 * Check whether the given node carries the attributes needed

 * to be a link element (or is one of the linking elements issued

 * from the (X)HTML DtDs).

 * This routine don't try to do full checking of the link validity

 * but tries to detect and return the appropriate link type.

 *

 * Returns the xlinkType of the node (XLINK_TYPE_NONE if there is no

 *         link detected.

 */

xlinkType 

xlinkIsLink	(xmlDocPtr doc, xmlNodePtr node) {

    xmlChar *type = NULL, *role = NULL;

    xlinkType ret = XLINK_TYPE_NONE;

    if (node == NULL) return(XLINK_TYPE_NONE);

    if (doc == NULL) doc = node->doc;

    if ((doc != NULL) && (doc->type == XML_HTML_DOCUMENT_NODE)) {

        /*

	 * This is an HTML document.

	 */

    } else if ((node->ns != NULL) &&

               (xmlStrEqual(node->ns->href, XHTML_NAMESPACE))) {

	/*

	 * !!!! We really need an IS_XHTML_ELEMENT function from HTMLtree.h @@@

	 */

        /*

	 * This is an XHTML element within an XML document

	 * Check whether it's one of the element able to carry links

	 * and in that case if it holds the attributes.

	 */

    }

    /*

     * We don't prevent a-priori having XML Linking constructs on

     * XHTML elements

     */

    type = xmlGetNsProp(node, BAD_CAST"type", XLINK_NAMESPACE);

    if (type != NULL) {

	if (xmlStrEqual(type, BAD_CAST "simple")) {

            ret = XLINK_TYPE_SIMPLE;

	} if (xmlStrEqual(type, BAD_CAST "extended")) {

	    role = xmlGetNsProp(node, BAD_CAST "role", XLINK_NAMESPACE);

	    if (role != NULL) {

		xmlNsPtr xlink;

		xlink = xmlSearchNs(doc, node, XLINK_NAMESPACE);

		if (xlink == NULL) {

		    /* Humm, fallback method */

		    if (xmlStrEqual(role, BAD_CAST"xlink:external-linkset")) 

			ret = XLINK_TYPE_EXTENDED_SET;

		} else {

		    xmlChar buf[200];

		    snprintf((char *) buf, sizeof(buf), "%s:external-linkset",

			     (char *) xlink->prefix);

                    buf[sizeof(buf) - 1] = 0;

		    if (xmlStrEqual(role, buf))

			ret = XLINK_TYPE_EXTENDED_SET;

		}

	    }

	    ret = XLINK_TYPE_EXTENDED;

	}

    }

    if (type != NULL) xmlFree(type);

    if (role != NULL) xmlFree(role);

    return(ret);

}

#endif /* LIBXML_XPTR_ENABLED */