Add a HasAssociation module for common code for has_* associations

1 files changed, 54 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/associations/has_association.rb b/activerecord/lib/active_record/associations/has_association.rb
new file mode 100644
index 0000000000..4407e2ea9a
--- /dev/null
+++ b/activerecord/lib/active_record/associations/has_association.rb
@@ -0,0 +1,54 @@
+module ActiveRecord
+  module Associations
+    # Included in all has_* associations (i.e. everything except belongs_to)
+    module HasAssociation #:nodoc:
+      protected
+        # Sets the owner attributes on the given record
+        def set_owner_attributes(record)
+          if @owner.persisted?
+            construct_owner_attributes.each { |key, value| record[key] = value }
+          end
+        end
+
+        # Returns a hash linking the owner to the association represented by the reflection
+        def construct_owner_attributes(reflection = @reflection)
+          attributes = {}
+          if reflection.macro == :belongs_to
+            attributes[reflection.association_primary_key] = @owner.send(reflection.primary_key_name)
+          else
+            attributes[reflection.primary_key_name] = @owner.send(reflection.active_record_primary_key)
+
+            if reflection.options[:as]
+              attributes["#{reflection.options[:as]}_type"] = @owner.class.base_class.name
+            end
+          end
+          attributes
+        end
+
+        # Builds an array of arel nodes from the owner attributes hash
+        def construct_owner_conditions(table = aliased_table, reflection = @reflection)
+          construct_owner_attributes(reflection).map do |attr, value|
+            table[attr].eq(value)
+          end
+        end
+
+        def construct_conditions
+          conditions = construct_owner_conditions
+          conditions << Arel.sql(sql_conditions) if sql_conditions
+          aliased_table.create_and(conditions)
+        end
+
+        if RUBY_VERSION < '1.9.2'
+          # Array#flatten has problems with recursive arrays before Ruby 1.9.2.
+          # Going one level deeper solves the majority of the problems.
+          def flatten_deeper(array)
+            array.collect { |element| (element.respond_to?(:flatten) && !element.is_a?(Hash)) ? element.flatten : element }.flatten
+          end
+        else
+          def flatten_deeper(array)
+            array.flatten
+          end
+        end
+    end
+  end
+end