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  #ifdef HAVE_CTYPE_H
 17  #include <ctype.h>
 18  #endif
 19  #ifdef HAVE_STDLIB_H
 20  #include <stdlib.h>
 21  #endif
 22  #ifdef HAVE_SYS_STAT_H
 23  #include <sys/stat.h>
 24  #endif
 25  #ifdef HAVE_FCNTL_H
 26  #include <fcntl.h>
 27  #endif
 28  #ifdef HAVE_UNISTD_H
 29  #include <unistd.h>
 30  #endif
 31  #ifdef HAVE_ZLIB_H
 32  #include <zlib.h>
 33  #endif
 34  
 35  #include <libxml/xmlmemory.h>
 36  #include <libxml/tree.h>
 37  #include <libxml/parser.h>
 38  #include <libxml/valid.h>
 39  #include <libxml/xlink.h>
 40  #include <libxml/globals.h>
 41  
 42  #define XLINK_NAMESPACE (BAD_CAST "http://www.w3.org/1999/xlink/namespace/")
 43  #define XHTML_NAMESPACE (BAD_CAST "http://www.w3.org/1999/xhtml/")
 44  
 45  /****************************************************************
 46   *								*
 47   *           Default setting and related functions		*
 48   *								*
 49   ****************************************************************/
 50  
 51  static xlinkHandlerPtr xlinkDefaultHandler = NULL;
 52  static xlinkNodeDetectFunc	xlinkDefaultDetect = NULL;
 53  
 54  /**
 55   * xlinkGetDefaultHandler:
 56   *
 57   * Get the default xlink handler.
 58   *
 59   * Returns the current xlinkHandlerPtr value.
 60   */
 61  xlinkHandlerPtr
 62  xlinkGetDefaultHandler(void) {
 63      return(xlinkDefaultHandler);
 64  }
 65  
 66  
 67  /**
 68   * xlinkSetDefaultHandler:
 69   * @handler:  the new value for the xlink handler block
 70   *
 71   * Set the default xlink handlers
 72   */
 73  void
 74  xlinkSetDefaultHandler(xlinkHandlerPtr handler) {
 75      xlinkDefaultHandler = handler;
 76  }
 77  
 78  /**
 79   * xlinkGetDefaultDetect:
 80   *
 81   * Get the default xlink detection routine
 82   *
 83   * Returns the current function or NULL;
 84   */
 85  xlinkNodeDetectFunc
 86  xlinkGetDefaultDetect	(void) {
 87      return(xlinkDefaultDetect);
 88  }
 89  
 90  /**
 91   * xlinkSetDefaultDetect:
 92   * @func: pointer to the new detection routine.
 93   *
 94   * Set the default xlink detection routine
 95   */
 96  void
 97  xlinkSetDefaultDetect	(xlinkNodeDetectFunc func) {
 98      xlinkDefaultDetect = func;
 99  }
100  
101  /****************************************************************
102   *								*
103   *                  The detection routines			*
104   *								*
105   ****************************************************************/
106  
107  
108  /**
109   * xlinkIsLink:
110   * @doc:  the document containing the node
111   * @node:  the node pointer itself
112   *
113   * Check whether the given node carries the attributes needed
114   * to be a link element (or is one of the linking elements issued
115   * from the (X)HTML DtDs).
116   * This routine don't try to do full checking of the link validity
117   * but tries to detect and return the appropriate link type.
118   *
119   * Returns the xlinkType of the node (XLINK_TYPE_NONE if there is no
120   *         link detected.
121   */
122  xlinkType
123  xlinkIsLink	(xmlDocPtr doc, xmlNodePtr node) {
124      xmlChar *type = NULL, *role = NULL;
125      xlinkType ret = XLINK_TYPE_NONE;
126  
127      if (node == NULL) return(XLINK_TYPE_NONE);
128      if (doc == NULL) doc = node->doc;
129      if ((doc != NULL) && (doc->type == XML_HTML_DOCUMENT_NODE)) {
130          /*
131  	 * This is an HTML document.
132  	 */
133      } else if ((node->ns != NULL) &&
134                 (xmlStrEqual(node->ns->href, XHTML_NAMESPACE))) {
135  	/*
136  	 * !!!! We really need an IS_XHTML_ELEMENT function from HTMLtree.h @@@
137  	 */
138          /*
139  	 * This is an XHTML element within an XML document
140  	 * Check whether it's one of the element able to carry links
141  	 * and in that case if it holds the attributes.
142  	 */
143      }
144  
145      /*
146       * We don't prevent a-priori having XML Linking constructs on
147       * XHTML elements
148       */
149      type = xmlGetNsProp(node, BAD_CAST"type", XLINK_NAMESPACE);
150      if (type != NULL) {
151  	if (xmlStrEqual(type, BAD_CAST "simple")) {
152              ret = XLINK_TYPE_SIMPLE;
153  	} else if (xmlStrEqual(type, BAD_CAST "extended")) {
154  	    role = xmlGetNsProp(node, BAD_CAST "role", XLINK_NAMESPACE);
155  	    if (role != NULL) {
156  		xmlNsPtr xlink;
157  		xlink = xmlSearchNs(doc, node, XLINK_NAMESPACE);
158  		if (xlink == NULL) {
159  		    /* Humm, fallback method */
160  		    if (xmlStrEqual(role, BAD_CAST"xlink:external-linkset"))
161  			ret = XLINK_TYPE_EXTENDED_SET;
162  		} else {
163  		    xmlChar buf[200];
164  		    snprintf((char *) buf, sizeof(buf), "%s:external-linkset",
165  			     (char *) xlink->prefix);
166                      buf[sizeof(buf) - 1] = 0;
167  		    if (xmlStrEqual(role, buf))
168  			ret = XLINK_TYPE_EXTENDED_SET;
169  
170  		}
171  
172  	    }
173  	    ret = XLINK_TYPE_EXTENDED;
174  	}
175      }
176  
177      if (type != NULL) xmlFree(type);
178      if (role != NULL) xmlFree(role);
179      return(ret);
180  }
181  #endif /* LIBXML_XPTR_ENABLED */
182  #define bottom_xlink
183  #include "elfgcchack.h"