Add the saxon:systemId extension

For https://bugzilla.gnome.org/show_bug.cgi?id=519926

Both Xalan and Saxon have a systemId function (in their respective
namespaces) to provide the URI of the file that is being transformed.
It would be nice to have that function in libxslt1.1 as well, because
then DocBook could use it[0].

[0] See line 250 et seq in
/usr/share/xml/docbook/stylesheet/nwalsh/common/stripns.xsl

diff --git a/libexslt/saxon.c b/libexslt/saxon.c
index fcb1547..60880c8 100644 (file)
--- a/libexslt/saxon.c
+++ b/libexslt/saxon.c
@@ -180,6 +180,32 @@ exsltSaxonEvaluateFunction (xmlXPathParserContextPtr ctxt, int nargs) {
 }
 
 /**
+ * exsltSaxonSystemIdFunction:
+ * @ctxt:  an XPath parser context
+ * @nargs: number of arguments
+ *
+ * Implements the SAXON systemId() function
+ *     string saxon:systemId ()
+ * This function returns the system ID of the document being styled.
+ */
+static void
+exsltSaxonSystemIdFunction(xmlXPathParserContextPtr ctxt, int nargs)
+{
+    if (ctxt == NULL)
+        return;
+    if (nargs != 0) {
+        xmlXPathSetArityError(ctxt);
+        return;
+    }
+
+    if ((ctxt->context) && (ctxt->context->doc) &&
+        (ctxt->context->doc->URL))
+       valuePush(ctxt, xmlXPathNewString(ctxt->context->doc->URL));
+    else
+       valuePush(ctxt, xmlXPathNewString(BAD_CAST ""));
+}
+
+/**
  * exsltSaxonLineNumberFunction:
  * @ctxt:  an XPath parser context
  * @nargs: number of arguments
@@ -264,4 +290,7 @@ exsltSaxonRegister (void) {
     xsltRegisterExtModuleFunction ((const xmlChar *) "line-number",
                                   SAXON_NAMESPACE,
                                   exsltSaxonLineNumberFunction);
+    xsltRegisterExtModuleFunction ((const xmlChar *) "systemId",
+                                  SAXON_NAMESPACE,
+                                  exsltSaxonSystemIdFunction);
 }