1 files changed, 194 insertions, 27 deletions

diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index d7bfaa5655..39ea885246 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -7,35 +7,51 @@ module ActiveRecord
     extend ActiveSupport::Concern
     include ActiveModel::AttributeMethods
 
+    included do
+      include Read
+      include Write
+      include BeforeTypeCast
+      include Query
+      include PrimaryKey
+      include TimeZoneConversion
+      include Dirty
+      include Serialization
+
+      # Returns the value of the attribute identified by <tt>attr_name</tt> after it has been typecast (for example,
+      # "2004-12-12" in a data column is cast to a date object, like Date.new(2004, 12, 12)).
+      # (Alias for the protected read_attribute method).
+      def [](attr_name)
+        read_attribute(attr_name)
+      end
+
+      # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+.
+      # (Alias for the protected write_attribute method).
+      def []=(attr_name, value)
+        write_attribute(attr_name, value)
+      end
+    end
+
     module ClassMethods
       # Generates all the attribute related methods for columns in the database
       # accessors, mutators and query methods.
       def define_attribute_methods
-        return if attribute_methods_generated?
-
-        if base_class == self
+        # Use a mutex; we don't want two thread simaltaneously trying to define
+        # attribute methods.
+        @attribute_methods_mutex.synchronize do
+          return if attribute_methods_generated?
+          superclass.define_attribute_methods unless self == base_class
           super(column_names)
           @attribute_methods_generated = true
-        else
-          base_class.define_attribute_methods
         end
       end
 
       def attribute_methods_generated?
-        if base_class == self
-          @attribute_methods_generated ||= false
-        else
-          base_class.attribute_methods_generated?
-        end
+        @attribute_methods_generated ||= false
       end
 
-      def undefine_attribute_methods(*args)
-        if base_class == self
-          super
-          @attribute_methods_generated = false
-        else
-          base_class.undefine_attribute_methods(*args)
-        end
+      def undefine_attribute_methods
+        super if attribute_methods_generated?
+        @attribute_methods_generated = false
       end
 
       def instance_method_already_implemented?(method_name)
@@ -43,19 +59,46 @@ module ActiveRecord
           raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord"
         end
 
-        super
+        if [Base, Model].include?(active_record_super)
+          super
+        else
+          # If B < A and A defines its own attribute method, then we don't want to overwrite that.
+          defined = method_defined_within?(method_name, superclass, superclass.generated_attribute_methods)
+          defined && !ActiveRecord::Base.method_defined?(method_name) || super
+        end
       end
 
       # A method name is 'dangerous' if it is already defined by Active Record, but
       # not by any ancestors. (So 'puts' is not dangerous but 'save' is.)
-      def dangerous_attribute_method?(method_name)
-        active_record = ActiveRecord::Base
-        superclass    = ActiveRecord::Base.superclass
+      def dangerous_attribute_method?(name)
+        method_defined_within?(name, Base)
+      end
+
+      def method_defined_within?(name, klass, sup = klass.superclass)
+        if klass.method_defined?(name) || klass.private_method_defined?(name)
+          if sup.method_defined?(name) || sup.private_method_defined?(name)
+            klass.instance_method(name).owner != sup.instance_method(name).owner
+          else
+            true
+          end
+        else
+          false
+        end
+      end
 
-        (active_record.method_defined?(method_name) ||
-         active_record.private_method_defined?(method_name)) &&
-        !superclass.method_defined?(method_name) &&
-        !superclass.private_method_defined?(method_name)
+      def attribute_method?(attribute)
+        super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, '')))
+      end
+
+      # Returns an array of column names as strings if it's not
+      # an abstract class and table exists.
+      # Otherwise it returns an empty array.
+      def attribute_names
+        @attribute_names ||= if !abstract_class? && table_exists?
+            column_names
+          else
+            []
+          end
       end
     end
 
@@ -94,9 +137,133 @@ module ActiveRecord
       super
     end
 
+    # Returns true if the given attribute is in the attributes hash
+    def has_attribute?(attr_name)
+      @attributes.has_key?(attr_name.to_s)
+    end
+
+    # Returns an array of names for the attributes available on this object.
+    def attribute_names
+      @attributes.keys
+    end
+
+    # Returns a hash of all the attributes with their names as keys and the values of the attributes as values.
+    def attributes
+      Hash[@attributes.map { |name, _| [name, read_attribute(name)] }]
+    end
+
+    # Returns an <tt>#inspect</tt>-like string for the value of the
+    # attribute +attr_name+. String attributes are truncated upto 50
+    # characters, and Date and Time attributes are returned in the
+    # <tt>:db</tt> format. Other attributes return the value of
+    # <tt>#inspect</tt> without modification.
+    #
+    #   person = Person.create!(:name => "David Heinemeier Hansson " * 3)
+    #
+    #   person.attribute_for_inspect(:name)
+    #   # => '"David Heinemeier Hansson David Heinemeier Hansson D..."'
+    #
+    #   person.attribute_for_inspect(:created_at)
+    #   # => '"2009-01-12 04:48:57"'
+    def attribute_for_inspect(attr_name)
+      value = read_attribute(attr_name)
+
+      if value.is_a?(String) && value.length > 50
+        "#{value[0..50]}...".inspect
+      elsif value.is_a?(Date) || value.is_a?(Time)
+        %("#{value.to_s(:db)}")
+      else
+        value.inspect
+      end
+    end
+
+    # Returns true if the specified +attribute+ has been set by the user or by a database load and is neither
+    # nil nor empty? (the latter only applies to objects that respond to empty?, most notably Strings).
+    def attribute_present?(attribute)
+      value = read_attribute(attribute)
+      !value.nil? && !(value.respond_to?(:empty?) && value.empty?)
+    end
+
+    # Returns the column object for the named attribute.
+    def column_for_attribute(name)
+      # FIXME: should this return a null object for columns that don't exist?
+      self.class.columns_hash[name.to_s]
+    end
+
     protected
-      def attribute_method?(attr_name)
-        attr_name == 'id' || (defined?(@attributes) && @attributes.include?(attr_name))
+
+    def clone_attributes(reader_method = :read_attribute, attributes = {})
+      attribute_names.each do |name|
+        attributes[name] = clone_attribute_value(reader_method, name)
+      end
+      attributes
+    end
+
+    def clone_attribute_value(reader_method, attribute_name)
+      value = send(reader_method, attribute_name)
+      value.duplicable? ? value.clone : value
+    rescue TypeError, NoMethodError
+      value
+    end
+
+    def arel_attributes_with_values_for_create(pk_attribute_allowed)
+      arel_attributes_with_values(attributes_for_create(pk_attribute_allowed))
+    end
+
+    def arel_attributes_with_values_for_update(attribute_names)
+      arel_attributes_with_values(attributes_for_update(attribute_names))
+    end
+
+    def attribute_method?(attr_name)
+      defined?(@attributes) && @attributes.include?(attr_name)
+    end
+
+    private
+
+    # Returns a Hash of the Arel::Attributes and attribute values that have been
+    # type casted for use in an Arel insert/update method.
+    def arel_attributes_with_values(attribute_names)
+      attrs = {}
+      arel_table = self.class.arel_table
+
+      attribute_names.each do |name|
+        attrs[arel_table[name]] = typecasted_attribute_value(name)
+      end
+      attrs
+    end
+
+    # Filters the primary keys and readonly attributes from the attribute names.
+    def attributes_for_update(attribute_names)
+      attribute_names.select do |name|
+        column_for_attribute(name) && !pk_attribute?(name) && !readonly_attribute?(name)
       end
+    end
+
+    # Filters out the primary keys, from the attribute names, when the primary
+    # key is to be generated (e.g. the id attribute has no value).
+    def attributes_for_create(pk_attribute_allowed)
+      @attributes.keys.select do |name|
+        column_for_attribute(name) && (pk_attribute_allowed || !pk_attribute?(name))
+      end
+    end
+
+    def readonly_attribute?(name)
+      self.class.readonly_attributes.include?(name)
+    end
+
+    def pk_attribute?(name)
+      column_for_attribute(name).primary
+    end
+
+    def typecasted_attribute_value(name)
+      if self.class.serialized_attributes.include?(name)
+        @attributes[name].serialized_value
+      else
+        # FIXME: we need @attributes to be used consistently.
+        # If the values stored in @attributes were already typecasted, this code
+        # could be simplified
+        read_attribute(name)
+      end
+    end
   end
 end