ENH: Added cmXMLParser::FindAttribute method

This method will help subclasses look for element attributes in their
StartElement methods.

Source/cmXMLParser.cxx

@@ -180,6 +180,23 @@ int cmXMLParser::IsSpace(char c)
   return isspace(c);
 }
 
+//----------------------------------------------------------------------------
+const char* cmXMLParser::FindAttribute(const char** atts,
+                                       const char* attribute)
+{
+  if(atts && attribute)
+    {
+    for(const char** a = atts; *a && *(a+1); a += 2)
+      {
+      if(strcmp(*a, attribute) == 0)
+        {
+        return *(a+1);
+        }
+      }
+    }
+  return 0;
+}
+
 //----------------------------------------------------------------------------
 void cmXMLParserStartElement(void* parser, const char *name,
                               const char **atts)

Source/cmXMLParser.h

@@ -105,6 +105,9 @@ protected:
   //! Send the given c-style string to the XML parser.
   int ParseBuffer(const char* buffer);
 
+  /** Helps subclasses search for attributes on elements.  */
+  static const char* FindAttribute(const char** atts, const char* attribute);
+
   //! Callbacks for the expat
   friend void cmXMLParserStartElement(void*, const char*, const char**);
   friend void cmXMLParserEndElement(void*, const char*);