1 files changed, 72 insertions, 9 deletions

diff --git a/activerecord/lib/active_record/store.rb b/activerecord/lib/active_record/store.rb
index 1c7b839e5e..25f528498e 100644
--- a/activerecord/lib/active_record/store.rb
+++ b/activerecord/lib/active_record/store.rb
@@ -1,6 +1,8 @@
+require 'active_support/core_ext/hash/indifferent_access'
+
 module ActiveRecord
   # Store gives you a thin wrapper around serialize for the purpose of storing hashes in a single column.
-  # It's like a simple key/value store backed into your record when you don't care about being able to
+  # It's like a simple key/value store baked into your record when you don't care about being able to
   # query that store outside the context of a single record.
   #
   # You can then declare accessors to this store that are then accessible just like any other attribute
@@ -10,41 +12,102 @@ module ActiveRecord
   # Make sure that you declare the database column used for the serialized store as a text, so there's
   # plenty of room.
   #
+  # You can set custom coder to encode/decode your serialized attributes to/from different formats.
+  # JSON, YAML, Marshal are supported out of the box. Generally it can be any wrapper that provides +load+ and +dump+.
+  #
   # Examples:
   #
   #   class User < ActiveRecord::Base
-  #     store :settings, accessors: [ :color, :homepage ]
+  #     store :settings, accessors: [ :color, :homepage ], coder: JSON
   #   end
   #
   #   u = User.new(color: 'black', homepage: '37signals.com')
   #   u.color                          # Accessor stored attribute
   #   u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor
   #
+  #   # There is no difference between strings and symbols for accessing custom attributes
+  #   u.settings[:country]  # => 'Denmark'
+  #   u.settings['country'] # => 'Denmark'
+  #
   #   # Add additional accessors to an existing store through store_accessor
   #   class SuperUser < User
   #     store_accessor :settings, :privileges, :servants
   #   end
+  #
+  # The stored attribute names can be retrieved using +stored_attributes+.
+  #
+  #   User.stored_attributes[:settings] # [:color, :homepage]
   module Store
     extend ActiveSupport::Concern
 
+    included do
+      class_attribute :stored_attributes, instance_accessor: false
+      self.stored_attributes = {}
+    end
+
     module ClassMethods
       def store(store_attribute, options = {})
-        serialize store_attribute, Hash
+        serialize store_attribute, IndifferentCoder.new(options[:coder])
         store_accessor(store_attribute, options[:accessors]) if options.has_key? :accessors
       end
 
       def store_accessor(store_attribute, *keys)
-        keys.flatten.each do |key|
+        keys = keys.flatten
+        keys.each do |key|
           define_method("#{key}=") do |value|
-            send("#{store_attribute}=", {}) unless send(store_attribute).is_a?(Hash)
-            send(store_attribute)[key] = value
-            send("#{store_attribute}_will_change!")
+            attribute = initialize_store_attribute(store_attribute)
+            if value != attribute[key]
+              send :"#{store_attribute}_will_change!"
+              attribute[key] = value
+            end
           end
 
           define_method(key) do
-            send("#{store_attribute}=", {}) unless send(store_attribute).is_a?(Hash)
-            send(store_attribute)[key]
+            initialize_store_attribute(store_attribute)[key]
+          end
+        end
+
+        self.stored_attributes[store_attribute] ||= []
+        self.stored_attributes[store_attribute] |= keys
+      end
+    end
+
+    private
+      def initialize_store_attribute(store_attribute)
+        attribute = send(store_attribute)
+        unless attribute.is_a?(HashWithIndifferentAccess)
+          attribute = IndifferentCoder.as_indifferent_hash(attribute)
+          send :"#{store_attribute}=", attribute
+        end
+        attribute
+      end
+
+    class IndifferentCoder
+      def initialize(coder_or_class_name)
+        @coder =
+          if coder_or_class_name.respond_to?(:load) && coder_or_class_name.respond_to?(:dump)
+            coder_or_class_name
+          else
+            ActiveRecord::Coders::YAMLColumn.new(coder_or_class_name || Object)
           end
+      end
+
+      def dump(obj)
+        @coder.dump self.class.as_indifferent_hash(obj)
+      end
+
+      def load(yaml)
+        self.class.as_indifferent_hash @coder.load(yaml)
+      end
+
+      def self.as_indifferent_hash(obj)
+        case obj
+        when HashWithIndifferentAccess
+          obj
+        when Hash
+          obj.with_indifferent_access
+        else
+          HashWithIndifferentAccess.new
         end
       end
     end