Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
tree: 8df787d428
Fetching contributors…

Cannot retrieve contributors at this time

453 lines (416 sloc) 16.521 kb
require 'active_support/core_ext/hash/keys'
require 'active_support/core_ext/class/attribute'
require 'active_support/deprecation'
module ActiveModel
class MissingAttributeError < NoMethodError
end
# == Active Model Attribute Methods
#
# <tt>ActiveModel::AttributeMethods</tt> provides a way to add prefixes and suffixes
# to your methods as well as handling the creation of Active Record like class methods
# such as +table_name+.
#
# The requirements to implement ActiveModel::AttributeMethods are to:
#
# * <tt>include ActiveModel::AttributeMethods</tt> in your object
# * Call each Attribute Method module method you want to add, such as
# attribute_method_suffix or attribute_method_prefix
# * Call <tt>define_attribute_methods</tt> after the other methods are
# called.
# * Define the various generic +_attribute+ methods that you have declared
#
# A minimal implementation could be:
#
# class Person
# include ActiveModel::AttributeMethods
#
# attribute_method_affix :prefix => 'reset_', :suffix => '_to_default!'
# attribute_method_suffix '_contrived?'
# attribute_method_prefix 'clear_'
# define_attribute_methods ['name']
#
# attr_accessor :name
#
# private
#
# def attribute_contrived?(attr)
# true
# end
#
# def clear_attribute(attr)
# send("#{attr}=", nil)
# end
#
# def reset_attribute_to_default!(attr)
# send("#{attr}=", "Default Name")
# end
# end
#
# Note that whenever you include ActiveModel::AttributeMethods in your class,
# it requires you to implement an <tt>attributes</tt> method which returns a hash
# with each attribute name in your model as hash key and the attribute value as
# hash value.
#
# Hash keys must be strings.
#
module AttributeMethods
extend ActiveSupport::Concern
NAME_COMPILABLE_REGEXP = /\A[a-zA-Z_]\w*[!?=]?\z/
CALL_COMPILABLE_REGEXP = /\A[a-zA-Z_]\w*[!?]?\z/
included do
class_attribute :attribute_method_matchers, :instance_writer => false
self.attribute_method_matchers = [ClassMethods::AttributeMethodMatcher.new]
end
module ClassMethods
def define_attr_method(name, value=nil, deprecation_warning = true, &block) #:nodoc:
# This deprecation_warning param is for internal use so that we can silence
# the warning from Active Record, because we are implementing more specific
# messages there instead.
#
# It doesn't apply to the original_#{name} method as we want to warn if
# people are calling that regardless.
if deprecation_warning
ActiveSupport::Deprecation.warn("define_attr_method is deprecated and will be removed without replacement.")
end
sing = singleton_class
sing.class_eval <<-eorb, __FILE__, __LINE__ + 1
remove_possible_method :'original_#{name}'
remove_possible_method :'_original_#{name}'
alias_method :'_original_#{name}', :'#{name}'
define_method :'original_#{name}' do
ActiveSupport::Deprecation.warn(
"This method is generated by ActiveModel::AttributeMethods::ClassMethods#define_attr_method, " \
"which is deprecated and will be removed."
)
send(:'_original_#{name}')
end
eorb
if block_given?
sing.send :define_method, name, &block
else
# If we can compile the method name, do it. Otherwise use define_method.
# This is an important *optimization*, please don't change it. define_method
# has slower dispatch and consumes more memory.
if name =~ NAME_COMPILABLE_REGEXP
sing.class_eval <<-RUBY, __FILE__, __LINE__ + 1
def #{name}; #{value.nil? ? 'nil' : value.to_s.inspect}; end
RUBY
else
value = value.to_s if value
sing.send(:define_method, name) { value }
end
end
end
# Declares a method available for all attributes with the given prefix.
# Uses +method_missing+ and <tt>respond_to?</tt> to rewrite the method.
#
# #{prefix}#{attr}(*args, &block)
#
# to
#
# #{prefix}attribute(#{attr}, *args, &block)
#
# An instance method <tt>#{prefix}attribute</tt> must exist and accept
# at least the +attr+ argument.
#
# For example:
#
# class Person
#
# include ActiveModel::AttributeMethods
# attr_accessor :name
# attribute_method_prefix 'clear_'
# define_attribute_methods [:name]
#
# private
#
# def clear_attribute(attr)
# send("#{attr}=", nil)
# end
# end
#
# person = Person.new
# person.name = "Bob"
# person.name # => "Bob"
# person.clear_name
# person.name # => nil
def attribute_method_prefix(*prefixes)
self.attribute_method_matchers += prefixes.map { |prefix| AttributeMethodMatcher.new :prefix => prefix }
undefine_attribute_methods
end
# Declares a method available for all attributes with the given suffix.
# Uses +method_missing+ and <tt>respond_to?</tt> to rewrite the method.
#
# #{attr}#{suffix}(*args, &block)
#
# to
#
# attribute#{suffix}(#{attr}, *args, &block)
#
# An <tt>attribute#{suffix}</tt> instance method must exist and accept at least
# the +attr+ argument.
#
# For example:
#
# class Person
#
# include ActiveModel::AttributeMethods
# attr_accessor :name
# attribute_method_suffix '_short?'
# define_attribute_methods [:name]
#
# private
#
# def attribute_short?(attr)
# send(attr).length < 5
# end
# end
#
# person = Person.new
# person.name = "Bob"
# person.name # => "Bob"
# person.name_short? # => true
def attribute_method_suffix(*suffixes)
self.attribute_method_matchers += suffixes.map { |suffix| AttributeMethodMatcher.new :suffix => suffix }
undefine_attribute_methods
end
# Declares a method available for all attributes with the given prefix
# and suffix. Uses +method_missing+ and <tt>respond_to?</tt> to rewrite
# the method.
#
# #{prefix}#{attr}#{suffix}(*args, &block)
#
# to
#
# #{prefix}attribute#{suffix}(#{attr}, *args, &block)
#
# An <tt>#{prefix}attribute#{suffix}</tt> instance method must exist and
# accept at least the +attr+ argument.
#
# For example:
#
# class Person
#
# include ActiveModel::AttributeMethods
# attr_accessor :name
# attribute_method_affix :prefix => 'reset_', :suffix => '_to_default!'
# define_attribute_methods [:name]
#
# private
#
# def reset_attribute_to_default!(attr)
# ...
# end
# end
#
# person = Person.new
# person.name # => 'Gem'
# person.reset_name_to_default!
# person.name # => 'Gemma'
def attribute_method_affix(*affixes)
self.attribute_method_matchers += affixes.map { |affix| AttributeMethodMatcher.new :prefix => affix[:prefix], :suffix => affix[:suffix] }
undefine_attribute_methods
end
def alias_attribute(new_name, old_name)
attribute_method_matchers.each do |matcher|
matcher_new = matcher.method_name(new_name).to_s
matcher_old = matcher.method_name(old_name).to_s
define_optimized_call self, matcher_new, matcher_old
end
end
# Declares the attributes that should be prefixed and suffixed by
# ActiveModel::AttributeMethods.
#
# To use, pass in an array of attribute names (as strings or symbols),
# be sure to declare +define_attribute_methods+ after you define any
# prefix, suffix or affix methods, or they will not hook in.
#
# class Person
#
# include ActiveModel::AttributeMethods
# attr_accessor :name, :age, :address
# attribute_method_prefix 'clear_'
#
# # Call to define_attribute_methods must appear after the
# # attribute_method_prefix, attribute_method_suffix or
# # attribute_method_affix declares.
# define_attribute_methods [:name, :age, :address]
#
# private
#
# def clear_attribute(attr)
# ...
# end
# end
def define_attribute_methods(attr_names)
attr_names.each { |attr_name| define_attribute_method(attr_name) }
end
def define_attribute_method(attr_name)
attribute_method_matchers.each do |matcher|
method_name = matcher.method_name(attr_name)
unless instance_method_already_implemented?(method_name)
generate_method = "define_method_#{matcher.method_missing_target}"
if respond_to?(generate_method)
send(generate_method, attr_name)
else
define_optimized_call generated_attribute_methods, method_name, matcher.method_missing_target, attr_name.to_s
end
end
end
attribute_method_matchers_cache.clear
end
# Removes all the previously dynamically defined methods from the class
def undefine_attribute_methods
generated_attribute_methods.module_eval do
instance_methods.each { |m| undef_method(m) }
end
attribute_method_matchers_cache.clear
end
# Returns true if the attribute methods defined have been generated.
def generated_attribute_methods #:nodoc:
@generated_attribute_methods ||= begin
mod = Module.new
include mod
mod
end
end
protected
def instance_method_already_implemented?(method_name)
generated_attribute_methods.method_defined?(method_name)
end
private
# The methods +method_missing+ and +respond_to?+ of this module are
# invoked often in a typical rails, both of which invoke the method
# +match_attribute_method?+. The latter method iterates through an
# array doing regular expression matches, which results in a lot of
# object creations. Most of the times it returns a +nil+ match. As the
# match result is always the same given a +method_name+, this cache is
# used to alleviate the GC, which ultimately also speeds up the app
# significantly (in our case our test suite finishes 10% faster with
# this cache).
def attribute_method_matchers_cache #:nodoc:
@attribute_method_matchers_cache ||= {}
end
def attribute_method_matcher(method_name) #:nodoc:
if attribute_method_matchers_cache.key?(method_name)
attribute_method_matchers_cache[method_name]
else
# Must try to match prefixes/suffixes first, or else the matcher with no prefix/suffix
# will match every time.
matchers = attribute_method_matchers.partition(&:plain?).reverse.flatten(1)
match = nil
matchers.detect { |method| match = method.match(method_name) }
attribute_method_matchers_cache[method_name] = match
end
end
# Define a method `name` in `mod` that dispatches to `send`
# using the given `extra` args. This fallbacks `define_method`
# and `send` if the given names cannot be compiled.
def define_optimized_call(mod, name, send, *extra) #:nodoc:
if name =~ NAME_COMPILABLE_REGEXP
defn = "def #{name}(*args)"
else
defn = "define_method(:'#{name}') do |*args|"
end
extra = (extra.map(&:inspect) << "*args").join(", ")
if send =~ CALL_COMPILABLE_REGEXP
target = "#{send}(#{extra})"
else
target = "send(:'#{send}', #{extra})"
end
mod.module_eval <<-RUBY, __FILE__, __LINE__ + 1
#{defn}
#{target}
end
RUBY
end
class AttributeMethodMatcher
attr_reader :prefix, :suffix, :method_missing_target
AttributeMethodMatch = Struct.new(:target, :attr_name, :method_name)
def initialize(options = {})
options.symbolize_keys!
if options[:prefix] == '' || options[:suffix] == ''
ActiveSupport::Deprecation.warn(
"Specifying an empty prefix/suffix for an attribute method is no longer " \
"necessary. If the un-prefixed/suffixed version of the method has not been " \
"defined when `define_attribute_methods` is called, it will be defined " \
"automatically."
)
end
@prefix, @suffix = options[:prefix] || '', options[:suffix] || ''
@regex = /^(#{Regexp.escape(@prefix)})(.+?)(#{Regexp.escape(@suffix)})$/
@method_missing_target = "#{@prefix}attribute#{@suffix}"
@method_name = "#{prefix}%s#{suffix}"
end
def match(method_name)
if @regex =~ method_name
AttributeMethodMatch.new(method_missing_target, $2, method_name)
else
nil
end
end
def method_name(attr_name)
@method_name % attr_name
end
def plain?
prefix.empty? && suffix.empty?
end
end
end
# Allows access to the object attributes, which are held in the
# <tt>@attributes</tt> hash, as though they were first-class methods. So a
# Person class with a name attribute can use Person#name and Person#name=
# and never directly use the attributes hash -- except for multiple assigns
# with ActiveRecord#attributes=. A Milestone class can also ask
# Milestone#completed? to test that the completed attribute is not +nil+
# or 0.
#
# It's also possible to instantiate related objects, so a Client class
# belonging to the clients table with a +master_id+ foreign key can
# instantiate master through Client#master.
def method_missing(method, *args, &block)
if respond_to_without_attributes?(method, true)
super
else
match = match_attribute_method?(method.to_s)
match ? attribute_missing(match, *args, &block) : super
end
end
# attribute_missing is like method_missing, but for attributes. When method_missing is
# called we check to see if there is a matching attribute method. If so, we call
# attribute_missing to dispatch the attribute. This method can be overloaded to
# customise the behaviour.
def attribute_missing(match, *args, &block)
__send__(match.target, match.attr_name, *args, &block)
end
# A Person object with a name attribute can ask <tt>person.respond_to?(:name)</tt>,
# <tt>person.respond_to?(:name=)</tt>, and <tt>person.respond_to?(:name?)</tt>
# which will all return +true+.
alias :respond_to_without_attributes? :respond_to?
def respond_to?(method, include_private_methods = false)
if super
true
elsif !include_private_methods && super(method, true)
# If we're here then we haven't found among non-private methods
# but found among all methods. Which means that the given method is private.
false
else
!match_attribute_method?(method.to_s).nil?
end
end
protected
def attribute_method?(attr_name)
attributes.include?(attr_name)
end
private
# Returns a struct representing the matching attribute method.
# The struct's attributes are prefix, base and suffix.
def match_attribute_method?(method_name)
match = self.class.send(:attribute_method_matcher, method_name)
match && attribute_method?(match.attr_name) ? match : nil
end
def missing_attribute(attr_name, stack)
raise ActiveModel::MissingAttributeError, "missing attribute: #{attr_name}", stack
end
end
end
Jump to Line
Something went wrong with that request. Please try again.