Force FieldML validate function to use a custom external entity loader to get around the internet requirement.

Author: alan-wu

core/src/FieldmlDOM.cpp

@@ -49,6 +49,7 @@
 #include <libxml/parser.h>
 #include <libxml/xmlmemory.h>
 #include <libxml/xmlschemas.h>
+#include <libxml/parserInternals.h>
 
 #include "ErrorContextAutostack.h"
 #include "Util.h"
@@ -113,6 +114,24 @@ static void addContextError( void *context, const char *msg, ... )
 
 //========================================================================
 
+xmlExternalEntityLoader defaultLoader = 0;
+
+
+xmlParserInputPtr
+xmlMyExternalEntityLoader(const char *URL, const char *ID,
+                          xmlParserCtxtPtr ctxt) {
+    xmlParserInputPtr ret = 0;
+
+    if (0 == strcmp(URL, "http://www.cellml.org/tools/cellml_1_1_schema/common/xlink-href.xsd"))
+   	 ret = xmlNewStringInputStream(ctxt, (const xmlChar *)HREF_STRING_XSD);
+    if (ret != NULL)
+        return(ret);
+    if (defaultLoader != NULL)
+        ret = defaultLoader(URL, ID, ctxt);
+    return(ret);
+}
+
+
 static int validate( FieldmlErrorHandler *errorHandler, xmlParserInputBufferPtr buffer, const char *resourceName )
 {
     xmlSchemaPtr schemas = NULL;
@@ -123,6 +142,11 @@ static int validate( FieldmlErrorHandler *errorHandler, xmlParserInputBufferPtr
 
     xmlSubstituteEntitiesDefault( 1 );
 
+    if (!defaultLoader)
+   	 defaultLoader = xmlGetExternalEntityLoader();
+
+    xmlSetExternalEntityLoader(xmlMyExternalEntityLoader);
+
     if( buffer == NULL )
     {
         return 1;

core/src/String_InternalXSD.cpp

@@ -41,6 +41,21 @@
 
 #include "String_InternalXSD.h"
 
+const char * const HREF_STRING_XSD = "<schema targetNamespace=\"http://www.w3.org/1999/xlink\" \ 
+        xmlns:xlink=\"http://www.w3.org/1999/xlink\" \
+        xmlns=\"http://www.w3.org/2001/XMLSchema\"> \
+  <annotation> \
+    <documentation xml:lang=\"en\"> \
+      This schema provides the XLink href attribute for use in the MathML2 \ 
+      schema. Written by Max Froumentin, W3C. \
+    </documentation> \
+  </annotation> \
+\
+  <attribute name=\"href\" type=\"anyURI\"/>\
+</schema> \
+";
+
+
 const char * const FML_STRING_FIELDML_XSD_LOCATION = "http://www.fieldml.org/resources/xml/0.5/FieldML_0.5.xsd";
 
 const char * const FML_STRING_FIELDML_XSD = "<?xml version=\"1.0\" encoding=\"utf-8\"?> \
@@ -49,8 +64,8 @@ const char * const FML_STRING_FIELDML_XSD = "<?xml version=\"1.0\" encoding=\"ut
     xmlns:xlink=\"http://www.w3.org/1999/xlink\" \
     > \
  \
-    <xs:import namespace=\"http://www.w3.org/1999/xlink\" \
-            schemaLocation=\"http://www.cellml.org/tools/cellml_1_1_schema/common/xlink-href.xsd\" /> \
+	<xs:import namespace=\"http://www.w3.org/1999/xlink\" \
+	schemaLocation=\"http://www.cellml.org/tools/cellml_1_1_schema/common/xlink-href.xsd\" /> \
  \
     <xs:complexType name=\"FieldmlRdfTargetType\"> \
         <xs:attribute name=\"id\" type=\"xs:string\" form=\"qualified\" use=\"optional\"/> \

core/src/String_InternalXSD.h

@@ -42,6 +42,8 @@
 #ifndef H_STRING_INTERNAL_XSD_H
 #define H_STRING_INTERNAL_XSD_H
 
+extern const char * const HREF_STRING_XSD;
+
 extern const char * const FML_STRING_FIELDML_XSD_LOCATION;
 
 extern const char * const FML_STRING_FIELDML_XSD;