1  /*
       2   * xlink.c : implementation of the hyperlinks detection module
       3   *           This version supports both XML XLinks and HTML simple links
       4   *
       5   * See Copyright for the status of this software.
       6   *
       7   * daniel@veillard.com
       8   */
       9  
      10  
      11  #define IN_LIBXML
      12  #include "libxml.h"
      13  
      14  #ifdef LIBXML_XPTR_ENABLED
      15  #include <string.h> /* for memset() only */
      16  #include <ctype.h>
      17  #include <stdlib.h>
      18  
      19  #include <libxml/xmlmemory.h>
      20  #include <libxml/tree.h>
      21  #include <libxml/parser.h>
      22  #include <libxml/xlink.h>
      23  
      24  #define XLINK_NAMESPACE (BAD_CAST "http://www.w3.org/1999/xlink/namespace/")
      25  #define XHTML_NAMESPACE (BAD_CAST "http://www.w3.org/1999/xhtml/")
      26  
      27  /****************************************************************
      28   *								*
      29   *           Default setting and related functions		*
      30   *								*
      31   ****************************************************************/
      32  
      33  static xlinkHandlerPtr xlinkDefaultHandler = NULL;
      34  static xlinkNodeDetectFunc	xlinkDefaultDetect = NULL;
      35  
      36  /**
      37   * xlinkGetDefaultHandler:
      38   *
      39   * Get the default xlink handler.
      40   *
      41   * Returns the current xlinkHandlerPtr value.
      42   */
      43  xlinkHandlerPtr
      44  xlinkGetDefaultHandler(void) {
      45      return(xlinkDefaultHandler);
      46  }
      47  
      48  
      49  /**
      50   * xlinkSetDefaultHandler:
      51   * @handler:  the new value for the xlink handler block
      52   *
      53   * Set the default xlink handlers
      54   */
      55  void
      56  xlinkSetDefaultHandler(xlinkHandlerPtr handler) {
      57      xlinkDefaultHandler = handler;
      58  }
      59  
      60  /**
      61   * xlinkGetDefaultDetect:
      62   *
      63   * Get the default xlink detection routine
      64   *
      65   * Returns the current function or NULL;
      66   */
      67  xlinkNodeDetectFunc
      68  xlinkGetDefaultDetect	(void) {
      69      return(xlinkDefaultDetect);
      70  }
      71  
      72  /**
      73   * xlinkSetDefaultDetect:
      74   * @func: pointer to the new detection routine.
      75   *
      76   * Set the default xlink detection routine
      77   */
      78  void
      79  xlinkSetDefaultDetect	(xlinkNodeDetectFunc func) {
      80      xlinkDefaultDetect = func;
      81  }
      82  
      83  /****************************************************************
      84   *								*
      85   *                  The detection routines			*
      86   *								*
      87   ****************************************************************/
      88  
      89  
      90  /**
      91   * xlinkIsLink:
      92   * @doc:  the document containing the node
      93   * @node:  the node pointer itself
      94   *
      95   * Check whether the given node carries the attributes needed
      96   * to be a link element (or is one of the linking elements issued
      97   * from the (X)HTML DtDs).
      98   * This routine don't try to do full checking of the link validity
      99   * but tries to detect and return the appropriate link type.
     100   *
     101   * Returns the xlinkType of the node (XLINK_TYPE_NONE if there is no
     102   *         link detected.
     103   */
     104  xlinkType
     105  xlinkIsLink	(xmlDocPtr doc, xmlNodePtr node) {
     106      xmlChar *type = NULL, *role = NULL;
     107      xlinkType ret = XLINK_TYPE_NONE;
     108  
     109      if (node == NULL) return(XLINK_TYPE_NONE);
     110      if (doc == NULL) doc = node->doc;
     111      if ((doc != NULL) && (doc->type == XML_HTML_DOCUMENT_NODE)) {
     112          /*
     113  	 * This is an HTML document.
     114  	 */
     115      } else if ((node->ns != NULL) &&
     116                 (xmlStrEqual(node->ns->href, XHTML_NAMESPACE))) {
     117  	/*
     118  	 * !!!! We really need an IS_XHTML_ELEMENT function from HTMLtree.h @@@
     119  	 */
     120          /*
     121  	 * This is an XHTML element within an XML document
     122  	 * Check whether it's one of the element able to carry links
     123  	 * and in that case if it holds the attributes.
     124  	 */
     125      }
     126  
     127      /*
     128       * We don't prevent a-priori having XML Linking constructs on
     129       * XHTML elements
     130       */
     131      type = xmlGetNsProp(node, BAD_CAST"type", XLINK_NAMESPACE);
     132      if (type != NULL) {
     133  	if (xmlStrEqual(type, BAD_CAST "simple")) {
     134              ret = XLINK_TYPE_SIMPLE;
     135  	} else if (xmlStrEqual(type, BAD_CAST "extended")) {
     136  	    role = xmlGetNsProp(node, BAD_CAST "role", XLINK_NAMESPACE);
     137  	    if (role != NULL) {
     138  		xmlNsPtr xlink;
     139  		xlink = xmlSearchNs(doc, node, XLINK_NAMESPACE);
     140  		if (xlink == NULL) {
     141  		    /* Humm, fallback method */
     142  		    if (xmlStrEqual(role, BAD_CAST"xlink:external-linkset"))
     143  			ret = XLINK_TYPE_EXTENDED_SET;
     144  		} else {
     145  		    xmlChar buf[200];
     146  		    snprintf((char *) buf, sizeof(buf), "%s:external-linkset",
     147  			     (char *) xlink->prefix);
     148                      buf[sizeof(buf) - 1] = 0;
     149  		    if (xmlStrEqual(role, buf))
     150  			ret = XLINK_TYPE_EXTENDED_SET;
     151  
     152  		}
     153  
     154  	    }
     155  	    ret = XLINK_TYPE_EXTENDED;
     156  	}
     157      }
     158  
     159      if (type != NULL) xmlFree(type);
     160      if (role != NULL) xmlFree(role);
     161      return(ret);
     162  }
     163  #endif /* LIBXML_XPTR_ENABLED */