Move Relation calculation methods to a separate module

activerecord/lib/active_record.rb

@@ -48,6 +48,7 @@ module ActiveRecord
     autoload :Attributes
     autoload :AutosaveAssociation
     autoload :Relation
+    autoload :RelationalCalculations
     autoload :Base
     autoload :Batches
     autoload :Calculations

activerecord/lib/active_record/relation.rb

@@ -4,6 +4,7 @@ module ActiveRecord
     delegate :length, :collect, :map, :each, :all?, :to => :to_a
     attr_reader :relation, :klass, :associations_to_preload, :eager_load_associations
 
+    include RelationalCalculations
     def initialize(klass, relation, readonly = false, preload = [], eager_load = [])
       @klass, @relation = klass, relation
       @readonly = readonly
@@ -204,20 +205,6 @@ module ActiveRecord
       end
     end
 
-    def count(*args)
-      column_name, options = construct_count_options_from_args(*args)
-      distinct = options[:distinct] ? true : false
-
-      column = if @klass.column_names.include?(column_name.to_s)
-        Arel::Attribute.new(@relation.table, column_name)
-      else
-        Arel::SqlLiteral.new(column_name == :all ? "*" : column_name.to_s)
-      end
-
-      relation = select(column.count(distinct))
-      @klass.connection.select_value(relation.to_sql).to_i
-    end
-
     def destroy_all
       to_a.each {|object| object.destroy}
       reset
@@ -351,36 +338,5 @@ module ActiveRecord
       }.join(',')
     end
 
-    def construct_count_options_from_args(*args)
-      options     = {}
-      column_name = :all
-
-      # We need to handle
-      #   count()
-      #   count(:column_name=:all)
-      #   count(options={})
-      #   count(column_name=:all, options={})
-      #   selects specified by scopes
-
-      # TODO : relation.projections only works when .select() was last in the chain. Fix it!
-      case args.size
-      when 0
-        column_name = @relation.send(:select_clauses).join(', ') if @relation.respond_to?(:projections) && @relation.projections.present?
-      when 1
-        if args[0].is_a?(Hash)
-          column_name = @relation.send(:select_clauses).join(', ') if @relation.respond_to?(:projections) && @relation.projections.present?
-          options = args[0]
-        else
-          column_name = args[0]
-        end
-      when 2
-        column_name, options = args
-      else
-        raise ArgumentError, "Unexpected parameters passed to count(): #{args.inspect}"
-      end
-
-      [column_name || :all, options]
-    end
-
   end
 end

activerecord/lib/active_record/relational_calculations.rb

@@ -0,0 +1,52 @@
+module ActiveRecord
+  module RelationalCalculations
+
+    def count(*args)
+      column_name, options = construct_count_options_from_args(*args)
+      distinct = options[:distinct] ? true : false
+
+      column = if @klass.column_names.include?(column_name.to_s)
+        Arel::Attribute.new(@relation.table, column_name)
+      else
+        Arel::SqlLiteral.new(column_name == :all ? "*" : column_name.to_s)
+      end
+
+      relation = select(column.count(distinct))
+      @klass.connection.select_value(relation.to_sql).to_i
+    end
+
+    private
+
+    def construct_count_options_from_args(*args)
+      options     = {}
+      column_name = :all
+
+      # We need to handle
+      #   count()
+      #   count(:column_name=:all)
+      #   count(options={})
+      #   count(column_name=:all, options={})
+      #   selects specified by scopes
+
+      # TODO : relation.projections only works when .select() was last in the chain. Fix it!
+      case args.size
+      when 0
+        column_name = @relation.send(:select_clauses).join(', ') if @relation.respond_to?(:projections) && @relation.projections.present?
+      when 1
+        if args[0].is_a?(Hash)
+          column_name = @relation.send(:select_clauses).join(', ') if @relation.respond_to?(:projections) && @relation.projections.present?
+          options = args[0]
+        else
+          column_name = args[0]
+        end
+      when 2
+        column_name, options = args
+      else
+        raise ArgumentError, "Unexpected parameters passed to count(): #{args.inspect}"
+      end
+
+      [column_name || :all, options]
+    end
+
+  end
+end