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-rw-r--r--activesupport/lib/active_support/core_ext/module/delegation.rb52
1 files changed, 52 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb
index ee8adae1cb..b927059c6b 100644
--- a/activesupport/lib/active_support/core_ext/module/delegation.rb
+++ b/activesupport/lib/active_support/core_ext/module/delegation.rb
@@ -156,4 +156,56 @@ class Module
end
end
end
+
+ def delegate!(*methods)
+ ActiveSupport::Deprecation.warn('Delegating to non-public methods is deprecated.', caller)
+
+ options = methods.pop
+ unless options.is_a?(Hash) && to = options[:to]
+ raise ArgumentError, "Delegation needs a target. Supply an options hash with a :to key as the last argument (e.g. delegate :hello, :to => :greeter)."
+ end
+ prefix, to, allow_nil = options[:prefix], options[:to], options[:allow_nil]
+
+ if prefix == true && to.to_s =~ /^[^a-z_]/
+ raise ArgumentError, "Can only automatically set the delegation prefix when delegating to a method."
+ end
+
+ method_prefix =
+ if prefix
+ "#{prefix == true ? to : prefix}_"
+ else
+ ''
+ end
+
+ file, line = caller.first.split(':', 2)
+ line = line.to_i
+
+ methods.each do |method|
+ method = method.to_s
+
+ if allow_nil
+ module_eval(<<-EOS, file, line - 2)
+ def #{method_prefix}#{method}(*args, &block) # def customer_name(*args, &block)
+ if #{to} || #{to}.respond_to?(:#{method}) # if client || client.respond_to?(:name)
+ #{to}.__send__(:#{method}, *args, &block) # client.__send__(:name, *args, &block)
+ end # end
+ end # end
+ EOS
+ else
+ exception = %(raise "#{self}##{method_prefix}#{method} delegated to #{to}.#{method}, but #{to} is nil: \#{self.inspect}")
+
+ module_eval(<<-EOS, file, line - 1)
+ def #{method_prefix}#{method}(*args, &block) # def customer_name(*args, &block)
+ #{to}.__send__(:#{method}, *args, &block) # client.__send__(:name, *args, &block)
+ rescue NoMethodError # rescue NoMethodError
+ if #{to}.nil? # if client.nil?
+ #{exception} # # add helpful message to the exception
+ else # else
+ raise # raise
+ end # end
+ end # end
+ EOS
+ end
+ end
+ end
end