allow model adapter to override condition hash matching in Rule, also clean up Mongoid adapter and specs

lib/cancan/model_adapters/abstract_adapter.rb

@@ -15,6 +15,17 @@ module CanCan
         false # override in subclass
       end
 
+      # Used to determine if this model adapter will override the matching behavior for a hash of conditions.
+      # If this returns true then matches_conditions_hash? will be called. See Rule#matches_conditions_hash
+      def self.override_conditions_hash_matching?(subject, conditions)
+        false
+      end
+
+      # Override if override_conditions_hash_matching? returns true
+      def self.matches_conditions_hash?(subject, conditions)
+        raise NotImplemented, "This model adapter does not support matching on a conditions hash."
+      end
+
       def initialize(model_class, rules)
         @model_class = model_class
         @rules = rules

lib/cancan/model_adapters/mongoid_adapter.rb

@@ -5,6 +5,14 @@ module CanCan
         model_class <= Mongoid::Document
       end
 
+      def self.override_conditions_hash_matching?(subject, conditions)
+        conditions.any? { |k,v| !k.kind_of?(Symbol) }
+      end
+
+      def self.matches_conditions_hash?(subject, conditions)
+        subject.class.where(conditions).include?(subject)  # just use Mongoid's where function
+      end
+
       def database_records
         @model_class.where(conditions)
       end
@@ -23,33 +31,6 @@ module CanCan
       end
     end
   end
-
-  # customize to handle Mongoid queries in ability definitions conditions
-  # Mongoid Criteria are simpler to check than normal conditions hashes
-  # 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
-  class Rule
-    def matches_conditions_hash_with_mongoid_subject?(subject, conditions = @conditions)
-      if defined?(::Mongoid) && subject.class.include?(::Mongoid::Document) && conditions.any?{|k,v| !k.kind_of?(Symbol)}
-        if conditions.empty?
-          true
-        else
-          subject.class.where(conditions).include?(subject)  # just use Mongoid's where function
-        end
-      else
-        matches_conditions_hash_without_mongoid_subject? subject, conditions
-      end
-    end
-
-    # could use alias_method_chain, but it's not worth adding activesupport as a gem dependency
-    alias_method :matches_conditions_hash_without_mongoid_subject?, :matches_conditions_hash?
-    alias_method :matches_conditions_hash?, :matches_conditions_hash_with_mongoid_subject?
-  end
 end
 
 # simplest way to add `accessible_by` to all Mongoid Documents

lib/cancan/rule.rb

@@ -88,19 +88,31 @@ module CanCan
       @subjects.any? { |sub| sub.kind_of?(Module) && (subject.kind_of?(sub) || subject.class.to_s == sub.to_s || subject.kind_of?(Module) && subject.ancestors.include?(sub)) }
     end
 
+    # Checks if the given subject matches the given conditions hash.
+    # This behavior can be overriden by a model adapter by defining two class methods:
+    # override_matching_for_conditions?(subject, conditions) and
+    # matches_conditions_hash?(subject, conditions)
     def matches_conditions_hash?(subject, conditions = @conditions)
-      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
+      if conditions.empty?
+        true
+      else
+        if model_adapter(subject).override_conditions_hash_matching? subject, conditions
+          model_adapter(subject).matches_conditions_hash? subject, conditions
         else
-          attribute == value
+          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
@@ -117,5 +129,9 @@ module CanCan
         @block.call(action, subject.class, subject, *extra_args)
       end
     end
+
+    def model_adapter(subject)
+      ModelAdapters::AbstractAdapter.adapter_class(subject_class?(subject) ? subject : subject.class)
+    end
   end
 end