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# Retain for backward compatibility. Methods are now included in Class.
module ClassInheritableAttributes # :nodoc:
end
# Allows attributes to be shared within an inheritance hierarchy, but where each descendant gets a copy of
# their parents' attributes, instead of just a pointer to the same. This means that the child can add elements
# to, for example, an array without those additions being shared with either their parent, siblings, or
# children, which is unlike the regular class-level attributes that are shared across the entire hierarchy.
class Class # :nodoc:
def class_inheritable_reader(*syms)
syms.each do |sym|
class_eval <<-EOS
def self.#{sym}
read_inheritable_attribute(:#{sym})
end
def #{sym}
self.class.#{sym}
end
EOS
end
end
def class_inheritable_writer(*syms)
syms.each do |sym|
class_eval <<-EOS
def self.#{sym}=(obj)
write_inheritable_attribute(:#{sym}, obj)
end
def #{sym}=(obj)
self.class.#{sym} = obj
end
EOS
end
end
def class_inheritable_array_writer(*syms)
syms.each do |sym|
class_eval <<-EOS
def self.#{sym}=(obj)
write_inheritable_array(:#{sym}, obj)
end
def #{sym}=(obj)
self.class.#{sym} = obj
end
EOS
end
end
def class_inheritable_hash_writer(*syms)
syms.each do |sym|
class_eval <<-EOS
def self.#{sym}=(obj)
write_inheritable_hash(:#{sym}, obj)
end
def #{sym}=(obj)
self.class.#{sym} = obj
end
EOS
end
end
def class_inheritable_accessor(*syms)
class_inheritable_reader(*syms)
class_inheritable_writer(*syms)
end
def class_inheritable_array(*syms)
class_inheritable_reader(*syms)
class_inheritable_array_writer(*syms)
end
def class_inheritable_hash(*syms)
class_inheritable_reader(*syms)
class_inheritable_hash_writer(*syms)
end
def inheritable_attributes
@inheritable_attributes ||= {}
end
def write_inheritable_attribute(key, value)
inheritable_attributes[key] = value
end
def write_inheritable_array(key, elements)
write_inheritable_attribute(key, []) if read_inheritable_attribute(key).nil?
write_inheritable_attribute(key, read_inheritable_attribute(key) + elements)
end
def write_inheritable_hash(key, hash)
write_inheritable_attribute(key, {}) if read_inheritable_attribute(key).nil?
write_inheritable_attribute(key, read_inheritable_attribute(key).merge(hash))
end
def read_inheritable_attribute(key)
inheritable_attributes[key]
end
def reset_inheritable_attributes
inheritable_attributes.clear
end
private
def inherited_with_inheritable_attributes(child)
inherited_without_inheritable_attributes(child) if respond_to?(:inherited_without_inheritable_attributes)
child.instance_variable_set('@inheritable_attributes', inheritable_attributes.dup)
end
if respond_to?(:inherited)
alias_method :inherited_without_inheritable_attributes, :inherited
end
alias_method :inherited, :inherited_with_inheritable_attributes
end
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