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0a4129cb7a
This patch was provided by Rafael França and greatly improves performance when an exception is raised. [Bug #11461] Before: Calculating ------------------------------------- default 86.209k i/100ms default raising 2.209k i/100ms ------------------------------------------------- default 1.953M (±11.0%) i/s - 9.655M default raising 21.826k (±13.5%) i/s - 108.241k After: Calculating ------------------------------------- default 72.211k i/100ms default raising 34.288k i/100ms ------------------------------------------------- default 2.013M (±18.7%) i/s - 9.460M default raising 623.950k (± 9.7%) i/s - 3.120M Benchmark: require 'delegate' require 'benchmark/ips' class Foo def name 'foo' end def bla raise end end class Bar < DelegateClass(Foo) end bar = Bar.new(Foo.new) Benchmark.ips do |b| b.report('default') { bar.name } b.report('default raising') { bar.bla rescue nil } end git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51806 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
405 lines
10 KiB
Ruby
405 lines
10 KiB
Ruby
# = delegate -- Support for the Delegation Pattern
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#
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# Documentation by James Edward Gray II and Gavin Sinclair
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##
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# This library provides three different ways to delegate method calls to an
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# object. The easiest to use is SimpleDelegator. Pass an object to the
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# constructor and all methods supported by the object will be delegated. This
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# object can be changed later.
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#
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# Going a step further, the top level DelegateClass method allows you to easily
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# setup delegation through class inheritance. This is considerably more
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# flexible and thus probably the most common use for this library.
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#
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# Finally, if you need full control over the delegation scheme, you can inherit
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# from the abstract class Delegator and customize as needed. (If you find
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# yourself needing this control, have a look at Forwardable which is also in
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# the standard library. It may suit your needs better.)
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#
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# SimpleDelegator's implementation serves as a nice example of the use of
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# Delegator:
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#
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# class SimpleDelegator < Delegator
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# def __getobj__
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# @delegate_sd_obj # return object we are delegating to, required
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# end
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#
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# def __setobj__(obj)
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# @delegate_sd_obj = obj # change delegation object,
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# # a feature we're providing
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# end
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# end
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#
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# == Notes
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#
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# Be advised, RDoc will not detect delegated methods.
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#
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class Delegator < BasicObject
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kernel = ::Kernel.dup
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kernel.class_eval do
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alias __raise__ raise
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[:to_s,:inspect,:=~,:!~,:===,:<=>,:eql?,:hash].each do |m|
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undef_method m
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end
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private_instance_methods.each do |m|
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if /\Ablock_given\?\z|iterator\?\z|\A__.*__\z/ =~ m
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next
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end
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undef_method m
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end
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end
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include kernel
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# :stopdoc:
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def self.const_missing(n)
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::Object.const_get(n)
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end
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# :startdoc:
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##
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# :method: raise
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# Use __raise__ if your Delegator does not have a object to delegate the
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# raise method call.
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#
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#
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# Pass in the _obj_ to delegate method calls to. All methods supported by
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# _obj_ will be delegated to.
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#
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def initialize(obj)
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__setobj__(obj)
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end
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#
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# Handles the magic of delegation through \_\_getobj\_\_.
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#
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def method_missing(m, *args, &block)
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r = true
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target = self.__getobj__ {r = false}
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if r && target.respond_to?(m)
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target.__send__(m, *args, &block)
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elsif ::Kernel.respond_to?(m, true)
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::Kernel.instance_method(m).bind(self).(*args, &block)
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else
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super(m, *args, &block)
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end
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end
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#
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# Checks for a method provided by this the delegate object by forwarding the
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# call through \_\_getobj\_\_.
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#
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def respond_to_missing?(m, include_private)
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r = true
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target = self.__getobj__ {r = false}
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r &&= target.respond_to?(m, include_private)
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if r && include_private && !target.respond_to?(m, false)
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warn "#{caller(3)[0]}: delegator does not forward private method \##{m}"
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return false
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end
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r
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end
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#
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# Returns the methods available to this delegate object as the union
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# of this object's and \_\_getobj\_\_ methods.
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#
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def methods(all=true)
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__getobj__.methods(all) | super
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end
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#
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# Returns the methods available to this delegate object as the union
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# of this object's and \_\_getobj\_\_ public methods.
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#
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def public_methods(all=true)
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__getobj__.public_methods(all) | super
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end
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#
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# Returns the methods available to this delegate object as the union
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# of this object's and \_\_getobj\_\_ protected methods.
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#
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def protected_methods(all=true)
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__getobj__.protected_methods(all) | super
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end
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# Note: no need to specialize private_methods, since they are not forwarded
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#
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# Returns true if two objects are considered of equal value.
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#
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def ==(obj)
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return true if obj.equal?(self)
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self.__getobj__ == obj
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end
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#
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# Returns true if two objects are not considered of equal value.
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#
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def !=(obj)
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return false if obj.equal?(self)
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__getobj__ != obj
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end
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#
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# Delegates ! to the \_\_getobj\_\_
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#
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def !
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!__getobj__
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end
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#
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# This method must be overridden by subclasses and should return the object
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# method calls are being delegated to.
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#
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def __getobj__
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__raise__ ::NotImplementedError, "need to define `__getobj__'"
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end
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#
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# This method must be overridden by subclasses and change the object delegate
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# to _obj_.
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#
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def __setobj__(obj)
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__raise__ ::NotImplementedError, "need to define `__setobj__'"
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end
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#
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# Serialization support for the object returned by \_\_getobj\_\_.
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#
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def marshal_dump
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ivars = instance_variables.reject {|var| /\A@delegate_/ =~ var}
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[
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:__v2__,
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ivars, ivars.map{|var| instance_variable_get(var)},
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__getobj__
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]
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end
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#
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# Reinitializes delegation from a serialized object.
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#
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def marshal_load(data)
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version, vars, values, obj = data
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if version == :__v2__
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vars.each_with_index{|var, i| instance_variable_set(var, values[i])}
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__setobj__(obj)
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else
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__setobj__(data)
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end
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end
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def initialize_clone(obj) # :nodoc:
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self.__setobj__(obj.__getobj__.clone)
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end
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def initialize_dup(obj) # :nodoc:
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self.__setobj__(obj.__getobj__.dup)
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end
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private :initialize_clone, :initialize_dup
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##
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# :method: trust
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# Trust both the object returned by \_\_getobj\_\_ and self.
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#
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##
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# :method: untrust
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# Untrust both the object returned by \_\_getobj\_\_ and self.
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#
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##
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# :method: taint
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# Taint both the object returned by \_\_getobj\_\_ and self.
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#
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##
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# :method: untaint
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# Untaint both the object returned by \_\_getobj\_\_ and self.
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#
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##
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# :method: freeze
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# Freeze both the object returned by \_\_getobj\_\_ and self.
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#
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[:trust, :untrust, :taint, :untaint, :freeze].each do |method|
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define_method method do
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__getobj__.send(method)
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super()
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end
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end
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@delegator_api = self.public_instance_methods
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def self.public_api # :nodoc:
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@delegator_api
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end
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end
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##
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# A concrete implementation of Delegator, this class provides the means to
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# delegate all supported method calls to the object passed into the constructor
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# and even to change the object being delegated to at a later time with
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# #__setobj__.
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#
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# class User
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# def born_on
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# Date.new(1989, 9, 10)
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# end
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# end
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#
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# class UserDecorator < SimpleDelegator
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# def birth_year
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# born_on.year
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# end
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# end
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#
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# decorated_user = UserDecorator.new(User.new)
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# decorated_user.birth_year #=> 1989
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# decorated_user.__getobj__ #=> #<User: ...>
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#
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# A SimpleDelegator instance can take advantage of the fact that SimpleDelegator
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# is a subclass of +Delegator+ to call <tt>super</tt> to have methods called on
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# the object being delegated to.
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#
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# class SuperArray < SimpleDelegator
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# def [](*args)
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# super + 1
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# end
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# end
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#
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# SuperArray.new([1])[0] #=> 2
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#
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# Here's a simple example that takes advantage of the fact that
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# SimpleDelegator's delegation object can be changed at any time.
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#
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# class Stats
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# def initialize
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# @source = SimpleDelegator.new([])
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# end
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#
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# def stats(records)
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# @source.__setobj__(records)
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#
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# "Elements: #{@source.size}\n" +
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# " Non-Nil: #{@source.compact.size}\n" +
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# " Unique: #{@source.uniq.size}\n"
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# end
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# end
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#
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# s = Stats.new
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# puts s.stats(%w{James Edward Gray II})
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# puts
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# puts s.stats([1, 2, 3, nil, 4, 5, 1, 2])
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#
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# Prints:
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#
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# Elements: 4
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# Non-Nil: 4
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# Unique: 4
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#
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# Elements: 8
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# Non-Nil: 7
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# Unique: 6
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#
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class SimpleDelegator<Delegator
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# Returns the current object method calls are being delegated to.
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def __getobj__
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unless defined?(@delegate_sd_obj)
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return yield if block_given?
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__raise__ ::ArgumentError, "not delegated"
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end
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@delegate_sd_obj
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end
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#
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# Changes the delegate object to _obj_.
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#
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# It's important to note that this does *not* cause SimpleDelegator's methods
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# to change. Because of this, you probably only want to change delegation
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# to objects of the same type as the original delegate.
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#
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# Here's an example of changing the delegation object.
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#
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# names = SimpleDelegator.new(%w{James Edward Gray II})
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# puts names[1] # => Edward
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# names.__setobj__(%w{Gavin Sinclair})
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# puts names[1] # => Sinclair
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#
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def __setobj__(obj)
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__raise__ ::ArgumentError, "cannot delegate to self" if self.equal?(obj)
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@delegate_sd_obj = obj
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end
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end
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def Delegator.delegating_block(mid) # :nodoc:
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lambda do |*args, &block|
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target = self.__getobj__
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target.__send__(mid, *args, &block)
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end
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end
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#
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# The primary interface to this library. Use to setup delegation when defining
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# your class.
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#
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# class MyClass < DelegateClass(ClassToDelegateTo) # Step 1
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# def initialize
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# super(obj_of_ClassToDelegateTo) # Step 2
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# end
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# end
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#
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# Here's a sample of use from Tempfile which is really a File object with a
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# few special rules about storage location and when the File should be
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# deleted. That makes for an almost textbook perfect example of how to use
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# delegation.
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#
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# class Tempfile < DelegateClass(File)
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# # constant and class member data initialization...
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#
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# def initialize(basename, tmpdir=Dir::tmpdir)
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# # build up file path/name in var tmpname...
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#
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# @tmpfile = File.open(tmpname, File::RDWR|File::CREAT|File::EXCL, 0600)
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#
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# # ...
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#
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# super(@tmpfile)
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#
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# # below this point, all methods of File are supported...
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# end
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#
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# # ...
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# end
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#
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def DelegateClass(superclass)
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klass = Class.new(Delegator)
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methods = superclass.instance_methods
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methods -= ::Delegator.public_api
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methods -= [:to_s,:inspect,:=~,:!~,:===]
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klass.module_eval do
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def __getobj__ # :nodoc:
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unless defined?(@delegate_dc_obj)
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return yield if block_given?
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__raise__ ::ArgumentError, "not delegated"
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end
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@delegate_dc_obj
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end
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def __setobj__(obj) # :nodoc:
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__raise__ ::ArgumentError, "cannot delegate to self" if self.equal?(obj)
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@delegate_dc_obj = obj
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end
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methods.each do |method|
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define_method(method, Delegator.delegating_block(method))
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end
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end
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klass.define_singleton_method :public_instance_methods do |all=true|
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super(all) - superclass.protected_instance_methods
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end
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klass.define_singleton_method :protected_instance_methods do |all=true|
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super(all) | superclass.protected_instance_methods
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end
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return klass
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end
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