Change namespace cache strategy

lib/rexml/attribute.rb

@@ -180,7 +180,7 @@ def element=( element )
     #
     # This method is usually not called directly.
     def remove
-      @element.attributes.delete self.name unless @element.nil?
+      @element.attributes.delete self unless @element.nil?
     end
 
     # Writes this attribute (EG, puts 'key="value"' to the output)
@@ -205,6 +205,15 @@ def xpath
     def document
       @element&.document
     end
+
+    # Returns true if this attribute is a namespace declaration, false otherwise.
+    #   "foo" => false
+    #   "xmlns" => true
+    #   "xmlns:foo" => true
+    #   "foo:xmlns" => false
+    def namespace_declaration?
+      prefix == 'xmlns' || (prefix.empty? && name == 'xmlns')
+    end
   end
 end
 #vim:ts=2 sw=2 noexpandtab:

lib/rexml/doctype.rb

@@ -113,23 +113,26 @@ def node_type
     end
 
     def attributes_of element
-      rv = []
-      each do |child|
-        child.each do |key,val|
-          rv << Attribute.new(key,val)
-        end if child.kind_of? AttlistDecl and child.element_name == element
+      raw_attributes = _attlist_mappings[element] || {}
+      raw_attributes.map do |key, value|
+        Attribute.new(key, value)
       end
-      rv
     end
 
     def attribute_of element, attribute
-      att_decl = find do |child|
-        child.kind_of? AttlistDecl and
-        child.element_name == element and
-        child.include? attribute
+      _attlist_mappings[element]&.[](attribute)
+    end
+
+    def _attlist_mappings
+      mapping = {}
+      grep(AttlistDecl).each do |child|
+        raw_attributes = mapping[child.element_name] ||= {}
+        child.each do |key, val|
+          # First declaration wins
+          raw_attributes[key] = val unless raw_attributes.key? key
+        end
       end
-      return nil unless att_decl
-      att_decl[attribute]
+      mapping
     end
 
     def clone