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Diffstat (limited to 'ruby_1_9_3/lib/delegate.rb')
| -rw-r--r-- | ruby_1_9_3/lib/delegate.rb | 392 |
1 files changed, 0 insertions, 392 deletions
diff --git a/ruby_1_9_3/lib/delegate.rb b/ruby_1_9_3/lib/delegate.rb deleted file mode 100644 index 2086a721f9..0000000000 --- a/ruby_1_9_3/lib/delegate.rb +++ /dev/null @@ -1,392 +0,0 @@ -# = delegate -- Support for the Delegation Pattern -# -# Documentation by James Edward Gray II and Gavin Sinclair - -## -# This library provides three different ways to delegate method calls to an -# object. The easiest to use is SimpleDelegator. Pass an object to the -# constructor and all methods supported by the object will be delegated. This -# object can be changed later. -# -# Going a step further, the top level DelegateClass method allows you to easily -# setup delegation through class inheritance. This is considerably more -# flexible and thus probably the most common use for this library. -# -# Finally, if you need full control over the delegation scheme, you can inherit -# from the abstract class Delegator and customize as needed. (If you find -# yourself needing this control, have a look at Forwardable which is also in -# the standard library. It may suit your needs better.) -# -# SimpleDelegator's implementation serves as a nice example if the use of -# Delegator: -# -# class SimpleDelegator < Delegator -# def initialize(obj) -# super # pass obj to Delegator constructor, required -# @delegate_sd_obj = obj # store obj for future use -# end -# -# def __getobj__ -# @delegate_sd_obj # return object we are delegating to, required -# end -# -# def __setobj__(obj) -# @delegate_sd_obj = obj # change delegation object, -# # a feature we're providing -# end -# end -# -# == Notes -# -# Be advised, RDoc will not detect delegated methods. -# -class Delegator < BasicObject - kernel = ::Kernel.dup - kernel.class_eval do - [:to_s,:inspect,:=~,:!~,:===,:<=>,:eql?,:hash].each do |m| - undef_method m - end - end - include kernel - - # :stopdoc: - def self.const_missing(n) - ::Object.const_get(n) - end - # :startdoc: - - # - # Pass in the _obj_ to delegate method calls to. All methods supported by - # _obj_ will be delegated to. - # - def initialize(obj) - __setobj__(obj) - end - - # - # Handles the magic of delegation through \_\_getobj\_\_. - # - def method_missing(m, *args, &block) - target = self.__getobj__ - begin - target.respond_to?(m) ? target.__send__(m, *args, &block) : super(m, *args, &block) - ensure - $@.delete_if {|t| %r"\A#{Regexp.quote(__FILE__)}:#{__LINE__-2}:"o =~ t} if $@ - end - end - - # - # Checks for a method provided by this the delegate object by forwarding the - # call through \_\_getobj\_\_. - # - def respond_to_missing?(m, include_private) - r = self.__getobj__.respond_to?(m, include_private) - if r && include_private && !self.__getobj__.respond_to?(m, false) - warn "#{caller(3)[0]}: delegator does not forward private method \##{m}" - return false - end - r - end - - # - # Returns the methods available to this delegate object as the union - # of this object's and \_\_getobj\_\_ methods. - # - def methods - __getobj__.methods | super - end - - # - # Returns the methods available to this delegate object as the union - # of this object's and \_\_getobj\_\_ public methods. - # - def public_methods(all=true) - __getobj__.public_methods(all) | super - end - - # - # Returns the methods available to this delegate object as the union - # of this object's and \_\_getobj\_\_ protected methods. - # - def protected_methods(all=true) - __getobj__.protected_methods(all) | super - end - - # Note: no need to specialize private_methods, since they are not forwarded - - # - # Returns true if two objects are considered of equal value. - # - def ==(obj) - return true if obj.equal?(self) - self.__getobj__ == obj - end - - # - # Returns true if two objects are not considered of equal value. - # - def !=(obj) - return false if obj.equal?(self) - __getobj__ != obj - end - - def ! - !__getobj__ - end - - # - # This method must be overridden by subclasses and should return the object - # method calls are being delegated to. - # - def __getobj__ - raise NotImplementedError, "need to define `__getobj__'" - end - - # - # This method must be overridden by subclasses and change the object delegate - # to _obj_. - # - def __setobj__(obj) - raise NotImplementedError, "need to define `__setobj__'" - end - - # - # Serialization support for the object returned by \_\_getobj\_\_. - # - def marshal_dump - ivars = instance_variables.reject {|var| /\A@delegate_/ =~ var} - [ - :__v2__, - ivars, ivars.map{|var| instance_variable_get(var)}, - __getobj__ - ] - end - - # - # Reinitializes delegation from a serialized object. - # - def marshal_load(data) - version, vars, values, obj = data - if version == :__v2__ - vars.each_with_index{|var, i| instance_variable_set(var, values[i])} - __setobj__(obj) - else - __setobj__(data) - end - end - - def initialize_clone(obj) # :nodoc: - self.__setobj__(obj.__getobj__.clone) - end - def initialize_dup(obj) # :nodoc: - self.__setobj__(obj.__getobj__.dup) - end - private :initialize_clone, :initialize_dup - - ## - # :method: trust - # Trust both the object returned by \_\_getobj\_\_ and self. - # - - ## - # :method: untrust - # Untrust both the object returned by \_\_getobj\_\_ and self. - # - - ## - # :method: taint - # Taint both the object returned by \_\_getobj\_\_ and self. - # - - ## - # :method: untaint - # Untaint both the object returned by \_\_getobj\_\_ and self. - # - - ## - # :method: freeze - # Freeze both the object returned by \_\_getobj\_\_ and self. - # - - [:trust, :untrust, :taint, :untaint, :freeze].each do |method| - define_method method do - __getobj__.send(method) - super() - end - end - - @delegator_api = self.public_instance_methods - def self.public_api # :nodoc: - @delegator_api - end -end - -## -# A concrete implementation of Delegator, this class provides the means to -# delegate all supported method calls to the object passed into the constructor -# and even to change the object being delegated to at a later time with -# #__setobj__. -# -# Here's a simple example that takes advantage of the fact that -# SimpleDelegator's delegation object can be changed at any time. -# -# class Stats -# def initialize -# @source = SimpleDelegator.new([]) -# end -# -# def stats(records) -# @source.__setobj__(records) -# -# "Elements: #{@source.size}\n" + -# " Non-Nil: #{@source.compact.size}\n" + -# " Unique: #{@source.uniq.size}\n" -# end -# end -# -# s = Stats.new -# puts s.stats(%w{James Edward Gray II}) -# puts -# puts s.stats([1, 2, 3, nil, 4, 5, 1, 2]) -# -# Prints: -# -# Elements: 4 -# Non-Nil: 4 -# Unique: 4 -# -# Elements: 8 -# Non-Nil: 7 -# Unique: 6 -# -class SimpleDelegator<Delegator - # Returns the current object method calls are being delegated to. - def __getobj__ - @delegate_sd_obj - end - - # - # Changes the delegate object to _obj_. - # - # It's important to note that this does *not* cause SimpleDelegator's methods - # to change. Because of this, you probably only want to change delegation - # to objects of the same type as the original delegate. - # - # Here's an example of changing the delegation object. - # - # names = SimpleDelegator.new(%w{James Edward Gray II}) - # puts names[1] # => Edward - # names.__setobj__(%w{Gavin Sinclair}) - # puts names[1] # => Sinclair - # - def __setobj__(obj) - raise ArgumentError, "cannot delegate to self" if self.equal?(obj) - @delegate_sd_obj = obj - end -end - -# :stopdoc: -def Delegator.delegating_block(mid) - lambda do |*args, &block| - target = self.__getobj__ - begin - target.__send__(mid, *args, &block) - ensure - $@.delete_if {|t| /\A#{Regexp.quote(__FILE__)}:#{__LINE__-2}:/o =~ t} if $@ - end - end -end -# :startdoc: - -# -# The primary interface to this library. Use to setup delegation when defining -# your class. -# -# class MyClass < DelegateClass(ClassToDelegateTo) # Step 1 -# def initialize -# super(obj_of_ClassToDelegateTo) # Step 2 -# end -# end -# -# Here's a sample of use from Tempfile which is really a File object with a -# few special rules about storage location and when the File should be -# deleted. That makes for an almost textbook perfect example of how to use -# delegation. -# -# class Tempfile < DelegateClass(File) -# # constant and class member data initialization... -# -# def initialize(basename, tmpdir=Dir::tmpdir) -# # build up file path/name in var tmpname... -# -# @tmpfile = File.open(tmpname, File::RDWR|File::CREAT|File::EXCL, 0600) -# -# # ... -# -# super(@tmpfile) -# -# # below this point, all methods of File are supported... -# end -# -# # ... -# end -# -def DelegateClass(superclass) - klass = Class.new(Delegator) - methods = superclass.instance_methods - methods -= ::Delegator.public_api - methods -= [:to_s,:inspect,:=~,:!~,:===] - klass.module_eval do - def __getobj__ # :nodoc: - @delegate_dc_obj - end - def __setobj__(obj) # :nodoc: - raise ArgumentError, "cannot delegate to self" if self.equal?(obj) - @delegate_dc_obj = obj - end - methods.each do |method| - define_method(method, Delegator.delegating_block(method)) - end - end - klass.define_singleton_method :public_instance_methods do |all=true| - super(all) - superclass.protected_instance_methods - end - klass.define_singleton_method :protected_instance_methods do |all=true| - super(all) | superclass.protected_instance_methods - end - return klass -end - -# :enddoc: - -if __FILE__ == $0 - class ExtArray<DelegateClass(Array) - def initialize() - super([]) - end - end - - ary = ExtArray.new - p ary.class - ary.push 25 - p ary - ary.push 42 - ary.each {|x| p x} - - foo = Object.new - def foo.test - 25 - end - def foo.iter - yield self - end - def foo.error - raise 'this is OK' - end - foo2 = SimpleDelegator.new(foo) - p foo2 - foo2.instance_eval{print "foo\n"} - p foo.test == foo2.test # => true - p foo2.iter{[55,true]} # => true - foo2.error # raise error! -end |