Add support for Mongoid::Criteria Symbol extensions (:age.gt => 10) along with specs.

lib/cancan/mongoid_additions.rb

@@ -26,6 +26,42 @@ module CanCan
     end
   end
 
+  # customize to handle Mongoid queries in ability definitions conditions
+  class CanDefinition
+    def matches_conditions_hash?(subject, conditions = @conditions)          
+      if subject.class.include?(Mongoid::Document)        # Mongoid Criteria are simpler to check than normal conditions hashes
+        if conditions.empty?  # When no conditions are given, true should be returned.
+                              # The default CanCan behavior relies on the fact that conditions.all? will return true when conditions is empty
+                              # The way ruby handles all? for empty hashes can be unexpected:
+                              #   {}.all?{|a| a == 5} 
+                              #   => true
+                              #   {}.all?{|a| a != 5} 
+                              #   => true
+          true
+        else
+          subject.class.where(conditions).include?(subject)  # just use Mongoid's where function
+        end
+      else 
+        conditions.all? do |name, value|
+          attribute = subject.send(name)
+          if value.kind_of?(Hash)
+            if attribute.kind_of? Array
+              attribute.any? { |element| matches_conditions_hash? element, value }
+            else
+              matches_conditions_hash? attribute, value
+            end
+          elsif value.kind_of?(Array) || value.kind_of?(Range)
+            value.include? attribute
+          else
+            attribute == value
+          end
+        end
+      end
+    end
+  end
+
+
+
   module MongoidAdditions
     module ClassMethods
       # Returns a scope which fetches only the records that the passed ability