diff options
Diffstat (limited to 'activerecord/lib/active_record/attribute_methods/read.rb')
| -rw-r--r-- | activerecord/lib/active_record/attribute_methods/read.rb | 78 |
1 files changed, 55 insertions, 23 deletions
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb index 506f5d75f9..1cf3aba41c 100644 --- a/activerecord/lib/active_record/attribute_methods/read.rb +++ b/activerecord/lib/active_record/attribute_methods/read.rb @@ -1,6 +1,38 @@ +require 'active_support/core_ext/module/method_transplanting' + module ActiveRecord module AttributeMethods module Read + ReaderMethodCache = Class.new(AttributeMethodCache) { + private + # We want to generate the methods via module_eval rather than + # define_method, because define_method is slower on dispatch. + # Evaluating many similar methods may use more memory as the instruction + # sequences are duplicated and cached (in MRI). define_method may + # be slower on dispatch, but if you're careful about the closure + # created, then define_method will consume much less memory. + # + # But sometimes the database might return columns with + # characters that are not allowed in normal method names (like + # 'my_column(omg)'. So to work around this we first define with + # the __temp__ identifier, and then use alias method to rename + # it to what we want. + # + # We are also defining a constant to hold the frozen string of + # the attribute name. Using a constant means that we do not have + # to allocate an object on each call to the attribute method. + # Making it frozen means that it doesn't get duped when used to + # key the @attributes_cache in read_attribute. + def method_body(method_name, const_name) + <<-EOMETHOD + def #{method_name} + name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{const_name} + read_attribute(name) { |n| missing_attribute(n, caller) } + end + EOMETHOD + end + }.new + extend ActiveSupport::Concern ATTRIBUTE_TYPES_CACHED_BY_DEFAULT = [:datetime, :timestamp, :time, :date] @@ -32,30 +64,30 @@ module ActiveRecord protected - # We want to generate the methods via module_eval rather than - # define_method, because define_method is slower on dispatch and - # uses more memory (because it creates a closure). - # - # But sometimes the database might return columns with - # characters that are not allowed in normal method names (like - # 'my_column(omg)'. So to work around this we first define with - # the __temp__ identifier, and then use alias method to rename - # it to what we want. - # - # We are also defining a constant to hold the frozen string of - # the attribute name. Using a constant means that we do not have - # to allocate an object on each call to the attribute method. - # Making it frozen means that it doesn't get duped when used to - # key the @attributes_cache in read_attribute. - def define_method_attribute(name) - safe_name = name.unpack('h*').first - generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1 - def __temp__#{safe_name} - read_attribute(AttrNames::ATTR_#{safe_name}) { |n| missing_attribute(n, caller) } + if Module.methods_transplantable? + def define_method_attribute(name) + method = ReaderMethodCache[name] + generated_attribute_methods.module_eval { define_method name, method } + end + else + def define_method_attribute(name) + safe_name = name.unpack('h*').first + temp_method = "__temp__#{safe_name}" + + ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name + + generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1 + def #{temp_method} + name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name} + read_attribute(name) { |n| missing_attribute(n, caller) } + end + STR + + generated_attribute_methods.module_eval do + alias_method name, temp_method + undef_method temp_method end - alias_method #{name.inspect}, :__temp__#{safe_name} - undef_method :__temp__#{safe_name} - STR + end end private |