lib/praxis-blueprints/field_expander.rb in praxis-blueprints-3.0 vs lib/praxis-blueprints/field_expander.rb in praxis-blueprints-3.1

@@ -1,15 +1,7 @@
 module Praxis
   class FieldExpander
-    class CircularExpansionError < StandardError
-      attr_reader :stack
-      def initialize(message, stack=[])
-        super(message)
-        @stack = stack
-      end
-    end
-
     def self.expand(object, fields=true)
       self.new.expand(object,fields)
     end
 
     attr_reader :stack
@@ -24,25 +16,30 @@
       end
     end
 
     def expand(object, fields=true)
       if stack[object].include? fields
-        raise CircularExpansionError, "Circular expansion detected for object #{object.inspect} with fields #{fields.inspect}"
+        if history[object].include? fields
+          return history[object][fields]
+        end
+        # We should probably never get here, since we should have a record
+        # of the history of an expansion if we're trying to redo it,
+        # but we should also be conservative and raise here just in case.
+        raise "Circular expansion detected for object #{object.inspect} with fields #{fields.inspect}"
       else
         stack[object] << fields
       end
 
-      if object.kind_of?(Praxis::View)
+      result = if object.kind_of?(Praxis::View)
         self.expand_view(object, fields)
       elsif object.kind_of? Attributor::Attribute
         self.expand_type(object.type, fields)
       else
         self.expand_type(object,fields)
       end
-    rescue CircularExpansionError => e
-      e.stack.unshift [object,fields]
-      raise
+
+      result
     ensure
       stack[object].delete fields
     end
 
     def expand_fields(attributes, fields)
@@ -65,24 +62,43 @@
       end
     end
 
 
     def expand_view(object,fields=true)
+      history[object][fields] = if object.kind_of?(Praxis::CollectionView)
+        []
+      else
+        {}
+      end
+
       result = expand_fields(object.contents, fields) do |dumpable, sub_fields|
         self.expand(dumpable, sub_fields)
       end
 
-      return [result] if object.kind_of?(Praxis::CollectionView)
-      result
+      if object.kind_of?(Praxis::CollectionView)
+        history[object][fields] << result
+      else
+        history[object][fields].merge!(result)
+      end
+      history[object][fields]
     end
 
 
     def expand_type(object,fields=true)
       unless object.respond_to?(:attributes)
         if object.respond_to?(:member_attribute)
-          fields = fields[0] if fields.kind_of? Array
-          return [self.expand(object.member_attribute.type, fields)]
+          if history[object].include? fields
+            return history[object][fields]
+          end
+          history[object][fields] = []
+
+          new_fields = fields.kind_of?(Array) ? fields[0] : fields
+
+          result = [self.expand(object.member_attribute.type, new_fields)]
+          history[object][fields].push(*result)
+
+          return result
         else
           return true
         end
       end
 
@@ -93,12 +109,14 @@
 
       if history[object].include? fields
         return history[object][fields]
       end
 
-      history[object][fields] = expand_fields(object.attributes, fields) do |dumpable, sub_fields|
+      history[object][fields] = {}
+      result = expand_fields(object.attributes, fields) do |dumpable, sub_fields|
         self.expand(dumpable.type, sub_fields)
       end
+      history[object][fields].merge!(result)
     end
 
   end
 end