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# frozen_string_literal: true
# Extends the module object with class/module and instance accessors for
# class/module attributes, just like the native attr* accessors for instance
# attributes, but does so on a per-thread basis.
#
# So the values are scoped within the Thread.current space under the class name
# of the module.
class Module
# Defines a per-thread class attribute and creates class and instance reader methods.
# The underlying per-thread class variable is set to +nil+, if it is not previously defined.
#
# module Current
# thread_mattr_reader :user
# end
#
# Current.user # => nil
# Thread.current[:attr_Current_user] = "DHH"
# Current.user # => "DHH"
#
# The attribute name must be a valid method name in Ruby.
#
# module Foo
# thread_mattr_reader :"1_Badname"
# end
# # => NameError: invalid attribute name: 1_Badname
#
# To omit the instance reader method, pass
# <tt>instance_reader: false</tt> or <tt>instance_accessor: false</tt>.
#
# class Current
# thread_mattr_reader :user, instance_reader: false
# end
#
# Current.new.user # => NoMethodError
def thread_mattr_reader(*syms, instance_reader: true, instance_accessor: true) # :nodoc:
syms.each do |sym|
raise NameError.new("invalid attribute name: #{sym}") unless /^[_A-Za-z]\w*$/.match?(sym)
# The following generated method concatenates `name` because we want it
# to work with inheritance via polymorphism.
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def self.#{sym}
Thread.current["attr_" + name + "_#{sym}"]
end
EOS
if instance_reader && instance_accessor
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def #{sym}
self.class.#{sym}
end
EOS
end
end
end
alias :thread_cattr_reader :thread_mattr_reader
# Defines a per-thread class attribute and creates a class and instance writer methods to
# allow assignment to the attribute.
#
# module Current
# thread_mattr_writer :user
# end
#
# Current.user = "DHH"
# Thread.current[:attr_Current_user] # => "DHH"
#
# To omit the instance writer method, pass
# <tt>instance_writer: false</tt> or <tt>instance_accessor: false</tt>.
#
# class Current
# thread_mattr_writer :user, instance_writer: false
# end
#
# Current.new.user = "DHH" # => NoMethodError
def thread_mattr_writer(*syms, instance_writer: true, instance_accessor: true) # :nodoc:
syms.each do |sym|
raise NameError.new("invalid attribute name: #{sym}") unless /^[_A-Za-z]\w*$/.match?(sym)
# The following generated method concatenates `name` because we want it
# to work with inheritance via polymorphism.
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def self.#{sym}=(obj)
Thread.current["attr_" + name + "_#{sym}"] = obj
end
EOS
if instance_writer && instance_accessor
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def #{sym}=(obj)
self.class.#{sym} = obj
end
EOS
end
end
end
alias :thread_cattr_writer :thread_mattr_writer
# Defines both class and instance accessors for class attributes.
#
# class Account
# thread_mattr_accessor :user
# end
#
# Account.user = "DHH"
# Account.user # => "DHH"
# Account.new.user # => "DHH"
#
# If a subclass changes the value, the parent class' value is not changed.
# Similarly, if the parent class changes the value, the value of subclasses
# is not changed.
#
# class Customer < Account
# end
#
# Customer.user = "Rafael"
# Customer.user # => "Rafael"
# Account.user # => "DHH"
#
# To omit the instance writer method, pass <tt>instance_writer: false</tt>.
# To omit the instance reader method, pass <tt>instance_reader: false</tt>.
#
# class Current
# thread_mattr_accessor :user, instance_writer: false, instance_reader: false
# end
#
# Current.new.user = "DHH" # => NoMethodError
# Current.new.user # => NoMethodError
#
# Or pass <tt>instance_accessor: false</tt>, to omit both instance methods.
#
# class Current
# thread_mattr_accessor :user, instance_accessor: false
# end
#
# Current.new.user = "DHH" # => NoMethodError
# Current.new.user # => NoMethodError
def thread_mattr_accessor(*syms, instance_reader: true, instance_writer: true, instance_accessor: true)
thread_mattr_reader(*syms, instance_reader: instance_reader, instance_accessor: instance_accessor)
thread_mattr_writer(*syms, instance_writer: instance_writer, instance_accessor: instance_accessor)
end
alias :thread_cattr_accessor :thread_mattr_accessor
end
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