Class: Class

Inherits:
Object show all
Defined in:
lib/blather/core_ext/active_support/inheritable_attributes.rb

Overview

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.

Constant Summary collapse

EMPTY_INHERITABLE_ATTRIBUTES =

Prevent this constant from being created multiple times

{}.freeze

Instance Method Summary collapse

Instance Method Details

#class_inheritable_accessor(*syms) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 53

def class_inheritable_accessor(*syms)
  class_inheritable_reader(*syms)
  class_inheritable_writer(*syms)
end

#class_inheritable_array(*syms) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 58

def class_inheritable_array(*syms)
  class_inheritable_reader(*syms)
  class_inheritable_array_writer(*syms)
end

#class_inheritable_array_writer(*syms) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 33

def class_inheritable_array_writer(*syms)
  syms.each do |sym|
    class_eval <<-EOS
      def self.#{sym}=(obj)
        write_inheritable_array(:#{sym}, obj)
      end
    EOS
  end
end

#class_inheritable_hash(*syms) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 63

def class_inheritable_hash(*syms)
  class_inheritable_reader(*syms)
  class_inheritable_hash_writer(*syms)
end

#class_inheritable_hash_writer(*syms) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 43

def class_inheritable_hash_writer(*syms)
  syms.each do |sym|
    class_eval <<-EOS
      def self.#{sym}=(obj)
        write_inheritable_hash(:#{sym}, obj)
      end
    EOS
  end
end

#class_inheritable_reader(*syms) ⇒ Object

:nodoc:



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 8

def class_inheritable_reader(*syms)
  syms.each do |sym|
    next if sym.is_a?(Hash)
    class_eval <<-EOS
      def self.#{sym}
        read_inheritable_attribute(:#{sym})
      end

      def #{sym}
        self.class.#{sym}
      end
    EOS
  end
end

#class_inheritable_writer(*syms) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 23

def class_inheritable_writer(*syms)
  syms.each do |sym|
    class_eval <<-EOS
      def self.#{sym}=(obj)
        write_inheritable_attribute(:#{sym}, obj)
      end
    EOS
  end
end

#inheritable_attributes ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 68

def inheritable_attributes
  @inheritable_attributes ||= EMPTY_INHERITABLE_ATTRIBUTES
end

#read_inheritable_attribute(key) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 89

def read_inheritable_attribute(key)
  inheritable_attributes[key]
end

#reset_inheritable_attributes ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 93

def reset_inheritable_attributes
  @inheritable_attributes = EMPTY_INHERITABLE_ATTRIBUTES
end

#write_inheritable_array(key, elements) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 79

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

#write_inheritable_attribute(key, value) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 72

def write_inheritable_attribute(key, value)
  if inheritable_attributes.equal?(EMPTY_INHERITABLE_ATTRIBUTES)
    @inheritable_attributes = {}
  end
  inheritable_attributes[key] = value
end

#write_inheritable_hash(key, hash) ⇒ Object 



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# File 'lib/blather/core_ext/active_support/inheritable_attributes.rb', line 84

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