# Copyright (c) 2006-2009 David Heinemeier Hansson
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
# Extracted From
# http://github.com/rails/rails/commit/971e2438d98326c994ec6d3ef8e37b7e868ed6e2
# Extends the class object with class and instance accessors for class attributes,
# just like the native attr* accessors for instance attributes.
#
# class Person
# cattr_accessor :hair_colors
# end
#
# Person.hair_colors = [:brown, :black, :blonde, :red]
class Class
def cattr_reader(*syms)
syms.flatten.each do |sym|
next if sym.is_a?(Hash)
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
unless defined? @@#{sym} # unless defined? @@hair_colors
@@#{sym} = nil # @@hair_colors = nil
end # end
#
def self.#{sym} # def self.hair_colors
@@#{sym} # @@hair_colors
end # end
#
def #{sym} # def hair_colors
@@#{sym} # @@hair_colors
end # end
EOS
end
end unless Class.respond_to?(:cattr_reader)
def cattr_writer(*syms)
options = syms.extract_options!
syms.flatten.each do |sym|
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
unless defined? @@#{sym} # unless defined? @@hair_colors
@@#{sym} = nil # @@hair_colors = nil
end # end
#
def self.#{sym}=(obj) # def self.hair_colors=(obj)
@@#{sym} = obj # @@hair_colors = obj
end # end
#
#{" #
def #{sym}=(obj) # def hair_colors=(obj)
@@#{sym} = obj # @@hair_colors = obj
end # end
" unless options[:instance_writer] == false } # # instance writer above is generated unless options[:instance_writer] == false
EOS
end
end unless Class.respond_to?(:cattr_writer)
def cattr_accessor(*syms)
cattr_reader(*syms)
cattr_writer(*syms)
end unless Class.respond_to?(:cattr_accessor)
# Defines class-level inheritable attribute reader. Attributes are available to subclasses,
# each subclass has a copy of parent's attribute.
#
# @param *syms<Array[#to_s]> Array of attributes to define inheritable reader for.
# @return <Array[#to_s]> Array of attributes converted into inheritable_readers.
#
# @api public
#
# @todo Do we want to block instance_reader via :instance_reader => false
# @todo It would be preferable that we do something with a Hash passed in
# (error out or do the same as other methods above) instead of silently
# moving on). In particular, this makes the return value of this function
# less useful.
def extlib_inheritable_reader(*ivars)
instance_reader = ivars.pop[:reader] if ivars.last.is_a?(Hash)
ivars.each do |ivar|
self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
def self.#{ivar}
return @#{ivar} if self.object_id == #{self.object_id} || defined?(@#{ivar})
ivar = superclass.#{ivar}
return nil if ivar.nil? && !#{self}.instance_variable_defined?("@#{ivar}")
@#{ivar} = ivar && !ivar.is_a?(Module) && !ivar.is_a?(Numeric) && !ivar.is_a?(TrueClass) && !ivar.is_a?(FalseClass) ? ivar.dup : ivar
end
RUBY
unless instance_reader == false
self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
def #{ivar}
self.class.#{ivar}
end
RUBY
end
end
end unless Class.respond_to?(:extlib_inheritable_reader)
# Defines class-level inheritable attribute writer. Attributes are available to subclasses,
# each subclass has a copy of parent's attribute.
#
# @param *syms<Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to
# define inheritable writer for.
# @option syms :instance_writer<Boolean> if true, instance-level inheritable attribute writer is defined.
# @return <Array[#to_s]> An Array of the attributes that were made into inheritable writers.
#
# @api public
#
# @todo We need a style for class_eval <<-HEREDOC. I'd like to make it
# class_eval(<<-RUBY, __FILE__, __LINE__), but we should codify it somewhere.
def extlib_inheritable_writer(*ivars)
instance_writer = ivars.pop[:writer] if ivars.last.is_a?(Hash)
ivars.each do |ivar|
self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
def self.#{ivar}=(obj)
@#{ivar} = obj
end
RUBY
unless instance_writer == false
self.class_eval <<-RUBY, __FILE__, __LINE__ + 1
def #{ivar}=(obj) self.class.#{ivar} = obj end
RUBY
end
self.send("#{ivar}=", yield) if block_given?
end
end unless Class.respond_to?(:extlib_inheritable_writer)
# Defines class-level inheritable attribute accessor. Attributes are available to subclasses,
# each subclass has a copy of parent's attribute.
#
# @param *syms<Array[*#to_s, Hash{:instance_writer => Boolean}]> Array of attributes to
# define inheritable accessor for.
# @option syms :instance_writer<Boolean> if true, instance-level inheritable attribute writer is defined.
# @return <Array[#to_s]> An Array of attributes turned into inheritable accessors.
#
# @api public
def extlib_inheritable_accessor(*syms, &block)
extlib_inheritable_reader(*syms)
extlib_inheritable_writer(*syms, &block)
end unless Class.respond_to?(:extlib_inheritable_accessor)
end
class Array
# Extracts options from a set of arguments. Removes and returns the last
# element in the array if it's a hash, otherwise returns a blank hash.
#
# def options(*args)
# args.extract_options!
# end
#
# options(1, 2) # => {}
# options(1, 2, :a => :b) # => {:a=>:b}
def extract_options!
last.is_a?(::Hash) ? pop : {}
end unless Array.new.respond_to?(:extract_options!)
# Wraps the object in an Array unless it's an Array. Converts the
# object to an Array using #to_ary if it implements that.
def self.wrap(object)
case object
when nil
[]
when self
object
else
if object.respond_to?(:to_ary)
object.to_ary
else
[object]
end
end
end unless Array.respond_to?(:wrap)
end