зеркало из https://github.com/github/ruby.git
129 строки
2.6 KiB
Ruby
129 строки
2.6 KiB
Ruby
# Delegation class that delegates even methods defined in super class,
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# which can not be covered with normal method_missing hack.
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#
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# Delegator is the abstract delegation class. Need to redefine
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# `__getobj__' method in the subclass. SimpleDelegator is the
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# concrete subclass for simple delegation.
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#
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# Usage:
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# foo = Object.new
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# foo2 = SimpleDelegator.new(foo)
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# foo.hash == foo2.hash # => false
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#
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# Foo = DelegateClass(Array)
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#
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# class ExtArray<DelegateClass(Array)
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# ...
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# end
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class Delegator
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def initialize(obj)
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preserved = ::Kernel.instance_methods
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preserved -= ["to_s","to_a","inspect","==","=~","==="]
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for t in self.type.ancestors
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preserved |= t.instance_methods
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preserved |= t.private_instance_methods
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preserved |= t.protected_instance_methods
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break if t == Delegator
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end
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for method in obj.methods
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next if preserved.include? method
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begin
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eval <<-EOS
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def self.#{method}(*args, &block)
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begin
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__getobj__.__send__(:#{method}, *args, &block)
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rescue Exception
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$@.delete_if{|s| /:in `__getobj__'$/ =~ s} #`
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$@.delete_if{|s| /^\\(eval\\):/ =~ s}
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raise
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end
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end
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EOS
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rescue SyntaxError
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raise NameError, "invalid identifier %s" % method, caller(4)
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end
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end
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end
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def __getobj__
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raise NotImplementError, "need to define `__getobj__'"
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end
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end
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class SimpleDelegator<Delegator
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def initialize(obj)
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super
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@obj = obj
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end
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def __getobj__
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@obj
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end
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def __setobj__(obj)
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@obj = obj
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end
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end
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# backward compatibility ^_^;;;
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Delegater = Delegator
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SimpleDelegater = SimpleDelegator
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#
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def DelegateClass(superclass)
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klass = Class.new
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methods = superclass.instance_methods(true)
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methods -= ::Kernel.instance_methods
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methods |= ["to_s","to_a","inspect","==","=~","==="]
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klass.module_eval <<-EOS
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def initialize(obj)
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@obj = obj
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end
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EOS
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for method in methods
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begin
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klass.module_eval <<-EOS
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def #{method}(*args, &block)
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begin
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@obj.__send__(:#{method}, *args, &block)
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rescue
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$@[0,2] = nil
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raise
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end
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end
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EOS
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rescue SyntaxError
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raise NameError, "invalid identifier %s" % method, caller(3)
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end
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end
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return klass;
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end
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if __FILE__ == $0
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class ExtArray<DelegateClass(Array)
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def initialize()
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super([])
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end
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end
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ary = ExtArray.new
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p ary.type
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ary.push 25
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p ary
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foo = Object.new
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def foo.test
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25
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end
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def foo.error
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raise 'this is OK'
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end
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foo2 = SimpleDelegator.new(foo)
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p foo.test == foo2.test # => true
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foo2.error # raise error!
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end
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