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module ActiveRecord
module AttributeMethods
module Read
extend ActiveSupport::Concern
included do
attribute_method_suffix ""
end
module ClassMethods
protected
def define_attribute_method(attr_name)
if self.serialized_attributes[attr_name]
define_read_method_for_serialized_attribute(attr_name)
else
define_read_method(attr_name.to_sym, attr_name, columns_hash[attr_name])
end
end
private
# Define read method for serialized attribute.
def define_read_method_for_serialized_attribute(attr_name)
evaluate_attribute_method attr_name, "def #{attr_name}; unserialize_attribute('#{attr_name}'); end", attr_name
end
# Define an attribute reader method. Cope with nil column.
def define_read_method(symbol, attr_name, column)
cast_code = column.type_cast_code('v') if column
access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
unless attr_name.to_s == self.primary_key.to_s
access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
end
if cache_attribute?(attr_name)
access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
end
evaluate_attribute_method attr_name, "def #{symbol}; #{access_code}; end", attr_name
end
end
# 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)).
def read_attribute(attr_name)
attr_name = attr_name.to_s
if !(value = @attributes[attr_name]).nil?
if column = column_for_attribute(attr_name)
if unserializable_attribute?(attr_name, column)
unserialize_attribute(attr_name)
else
column.type_cast(value)
end
else
value
end
else
nil
end
end
# Returns true if the attribute is of a text column and marked for serialization.
def unserializable_attribute?(attr_name, column)
column.text? && self.class.serialized_attributes[attr_name]
end
# Returns the unserialized object of the attribute.
def unserialize_attribute(attr_name)
unserialized_object = object_from_yaml(@attributes[attr_name])
if unserialized_object.is_a?(self.class.serialized_attributes[attr_name]) || unserialized_object.nil?
@attributes.frozen? ? unserialized_object : @attributes[attr_name] = unserialized_object
else
raise SerializationTypeMismatch,
"#{attr_name} was supposed to be a #{self.class.serialized_attributes[attr_name]}, but was a #{unserialized_object.class.to_s}"
end
end
private
def attribute(attribute_name)
read_attribute(attribute_name)
end
end
end
end
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