/usr/lib/ruby/vendor_ruby/active_support/concern.rb is in ruby-activesupport-3.2 3.2.16-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 | require 'active_support/deprecation'
module ActiveSupport
# A typical module looks like this:
#
# module M
# def self.included(base)
# base.extend ClassMethods
# base.class_eval do
# scope :disabled, where(:disabled => true)
# end
# end
#
# module ClassMethods
# ...
# end
# end
#
# By using <tt>ActiveSupport::Concern</tt> the above module could instead be written as:
#
# require 'active_support/concern'
#
# module M
# extend ActiveSupport::Concern
#
# included do
# scope :disabled, where(:disabled => true)
# end
#
# module ClassMethods
# ...
# end
# end
#
# Moreover, it gracefully handles module dependencies. Given a +Foo+ module and a +Bar+
# module which depends on the former, we would typically write the following:
#
# module Foo
# def self.included(base)
# base.class_eval do
# def self.method_injected_by_foo
# ...
# end
# end
# end
# end
#
# module Bar
# def self.included(base)
# base.method_injected_by_foo
# end
# end
#
# class Host
# include Foo # We need to include this dependency for Bar
# include Bar # Bar is the module that Host really needs
# end
#
# But why should +Host+ care about +Bar+'s dependencies, namely +Foo+? We could try to hide
# these from +Host+ directly including +Foo+ in +Bar+:
#
# module Bar
# include Foo
# def self.included(base)
# base.method_injected_by_foo
# end
# end
#
# class Host
# include Bar
# end
#
# Unfortunately this won't work, since when +Foo+ is included, its <tt>base</tt> is the +Bar+ module,
# not the +Host+ class. With <tt>ActiveSupport::Concern</tt>, module dependencies are properly resolved:
#
# require 'active_support/concern'
#
# module Foo
# extend ActiveSupport::Concern
# included do
# class_eval do
# def self.method_injected_by_foo
# ...
# end
# end
# end
# end
#
# module Bar
# extend ActiveSupport::Concern
# include Foo
#
# included do
# self.method_injected_by_foo
# end
# end
#
# class Host
# include Bar # works, Bar takes care now of its dependencies
# end
#
module Concern
def self.extended(base)
base.instance_variable_set("@_dependencies", [])
end
def append_features(base)
if base.instance_variable_defined?("@_dependencies")
base.instance_variable_get("@_dependencies") << self
return false
else
return false if base < self
@_dependencies.each { |dep| base.send(:include, dep) }
super
base.extend const_get("ClassMethods") if const_defined?("ClassMethods")
if const_defined?("InstanceMethods")
base.send :include, const_get("InstanceMethods")
ActiveSupport::Deprecation.warn "The InstanceMethods module inside ActiveSupport::Concern will be " \
"no longer included automatically. Please define instance methods directly in #{self} instead.", caller
end
base.class_eval(&@_included_block) if instance_variable_defined?("@_included_block")
end
end
def included(base = nil, &block)
if base.nil?
@_included_block = block
else
super
end
end
end
end
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