From cc6799168a4923a0c0a2ae5d2199dd560fccb302 Mon Sep 17 00:00:00 2001 From: matz Date: Wed, 5 Oct 2005 16:15:16 +0000 Subject: * range.c (rb_range_beg_len): should return Qfalse for non-range object. * pack.c (EXTEND16): [ruby-dev:27383] * eval.c (set_trace_func): add rb_secure(4) to prevent adding tracing function. * lib/delegate.rb: document update from James Edward Gray II . [ruby-core:05942] * process.c (proc_daemon): should restrict execution on levels higher than $SAFE=2. suggested by URABE Shyouhei . * lib/forwardable.rb: replaced by new implementation from . [ruby-core:05899] * file.c (path_check_0): disallow sticky world writable directory in PATH (and $LOAD_PATH). [ruby-dev:27226] * numeric.c (fix_idiv): 1.div(1.0) should return integer value. [ruby-dev:27235] * lib/yaml.rb: require 'yaml/constants'. [ruby-core:5776] * lib/xmlrpc/client.rb (XMLRPC::Client::do_rpc): add charset information to content-type header.[ruby-core:5127] * lib/xmlrpc/server.rb (CGIServer::serve): ditto. * lib/xmlrpc/server.rb (ModRubyServer::serve): ditto. * lib/xmlrpc/server.rb (WEBrickServlet::service): ditto. * test/dbm/test_dbm.rb (TestDBM::test_s_open_error): remove test_s_open_error test to detect duplicate open. [ruby-dev:27202] * eval.c (splat_value): use to_a to splat non Array object. * object.c (nil_to_a): remove nil.to_a. [experimental] git-svn-id: http://svn.ruby-lang.org/repos/ruby/trunk@9349 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- lib/delegate.rb | 195 ++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 174 insertions(+), 21 deletions(-) (limited to 'lib/delegate.rb') diff --git a/lib/delegate.rb b/lib/delegate.rb index 83aaf292a..b54b57d7b 100644 --- a/lib/delegate.rb +++ b/lib/delegate.rb @@ -1,21 +1,119 @@ -# Delegation class that delegates even methods defined in super class, -# which can not be covered with normal method_missing hack. -# -# Delegator is the abstract delegation class. Need to redefine -# `__getobj__' method in the subclass. SimpleDelegator is the -# concrete subclass for simple delegation. +# = delegate -- Support for the Delegation Pattern # -# Usage: -# foo = Object.new -# foo2 = SimpleDelegator.new(foo) -# foo.hash == foo2.hash # => false +# Documentation by James Edward Gray II and Gavin Sinclair # -# Foo = DelegateClass(Array) +# == Introduction # -# class ExtArraydelegate.rb provides full-class delegation via the +# DelegateClass() method. For single-method delegation via +# def_delegator(), see forwardable.rb. +# +# == Examples +# +# === SimpleDelegator +# +# 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 +# +# === DelegateClass() +# +# Here's a sample of use from tempfile.rb. +# +# A _Tempfile_ object is really just a _File_ object with a few special rules +# about storage location and/or 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 +# +# === Delegator +# +# SimpleDelegator's implementation serves as a nice example here. +# +# class SimpleDelegator < Delegator +# def initialize(obj) +# super # pass obj to Delegator constructor, required +# @_sd_obj = obj # store obj for future use +# end +# +# def __getobj__ +# @_sd_obj # return object we are delegating to, required +# end +# +# def __setobj__(obj) +# @_sd_obj = obj # change delegation object, a feature we're providing +# end +# +# # ... +# end +# +# Delegator is an abstract class used to build delegator pattern objects from +# subclasses. Subclasses should redefine \_\_getobj\_\_. For a concrete +# implementation, see SimpleDelegator. +# class Delegator preserved = ["__id__", "object_id", "__send__", "respond_to?"] instance_methods.each do |m| @@ -23,10 +121,15 @@ class Delegator undef_method m end + # + # 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) begin target = self.__getobj__ @@ -40,42 +143,79 @@ class Delegator end end + # + # Checks for a method provided by this the delegate object by fowarding the + # call through \_\_getobj\_\_. + # def respond_to?(m) return true if super return self.__getobj__.respond_to?(m) 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 __getobj__ end + # Reinitializes delegation from a serialized object. def marshal_load(obj) __setobj__(obj) 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\_\_ . +# class SimpleDelegator Edward + # names.__setobj__(%w{Gavin Sinclair}) + # puts names[1] # => Sinclair + # def __setobj__(obj) raise ArgumentError, "cannot delegate to self" if self.equal?(obj) @_sd_obj = obj end + # Clone support for the object returned by \_\_getobj\_\_. def clone copy = super copy.__setobj__(__getobj__.clone) copy end + # Duplication support for the object returned by \_\_getobj\_\_. def dup copy = super copy.__setobj__(__getobj__.dup) @@ -83,10 +223,21 @@ class SimpleDelegator