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#
# Copyright 2014 Seth Vargo <sethvargo@gmail.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
require_relative 'cleanroom/errors'
require_relative 'cleanroom/version'
module Cleanroom
#
# Callback for when this module is included.
#
# @param [Class] base
#
def self.included(base)
base.send(:extend, ClassMethods)
base.send(:include, InstanceMethods)
end
#
# Callback for when this module is included.
#
# @param [Class] base
#
def self.extended(base)
base.send(:extend, ClassMethods)
base.send(:include, InstanceMethods)
end
#
# Class methods
#
module ClassMethods
#
# Evaluate the file in the context of the cleanroom.
#
# @param [Class] instance
# the instance of the class to evaluate against
# @param [String] filepath
# the path of the file to evaluate
#
def evaluate_file(instance, filepath)
absolute_path = File.expand_path(filepath)
file_contents = IO.read(absolute_path)
evaluate(instance, file_contents, absolute_path, 1)
end
#
# Evaluate the string or block in the context of the cleanroom.
#
# @param [Class] instance
# the instance of the class to evaluate against
# @param [Array<String>] args
# the args to +instance_eval+
# @param [Proc] block
# the block to +instance_eval+
#
def evaluate(instance, *args, &block)
cleanroom.new(instance).instance_eval(*args, &block)
end
#
# Expose the given method to the DSL.
#
# @param [Symbol] name
#
def expose(name)
unless public_method_defined?(name)
raise NameError, "undefined method `#{name}' for class `#{self.name}'"
end
exposed_methods[name] = true
end
#
# The list of exposed methods.
#
# @return [Hash]
#
def exposed_methods
@exposed_methods ||= from_superclass(:exposed_methods, {}).dup
end
private
#
# The cleanroom instance for this class. This method is intentionally
# NOT cached!
#
# @return [Class]
#
def cleanroom
exposed = exposed_methods.keys
parent = self.name || 'Anonymous'
Class.new(Object) do
class << self
def class_eval
raise Cleanroom::InaccessibleError.new(:class_eval, self)
end
def instance_eval
raise Cleanroom::InaccessibleError.new(:instance_eval, self)
end
end
define_method(:initialize) do |instance|
define_singleton_method(:__instance__) do
unless caller[0].include?(__FILE__)
raise Cleanroom::InaccessibleError.new(:__instance__, self)
end
instance
end
end
exposed.each do |exposed_method|
define_method(exposed_method) do |*args, &block|
__instance__.public_send(exposed_method, *args, &block)
end
end
define_method(:class_eval) do
raise Cleanroom::InaccessibleError.new(:class_eval, self)
end
define_method(:inspect) do
"#<#{parent} (Cleanroom)>"
end
alias_method :to_s, :inspect
end
end
#
# Get the value from the superclass, if it responds, otherwise return
# +default+. Since class instance variables are **not** inherited upon
# subclassing, this is a required check to ensure subclasses inherit
# exposed DSL methods.
#
# @param [Symbol] m
# the name of the method to find
# @param [Object] default
# the default value to return if not found
#
def from_superclass(m, default = nil)
return default if superclass == Cleanroom
superclass.respond_to?(m) ? superclass.send(m) : default
end
end
#
# Instance Mehtods
#
module InstanceMethods
#
# Evaluate the file against the current instance.
#
# @param (see Cleanroom.evaluate_file)
# @return [self]
#
def evaluate_file(filepath)
self.class.evaluate_file(self, filepath)
self
end
#
# Evaluate the contents against the current instance.
#
# @param (see Cleanroom.evaluate_file)
# @return [self]
#
def evaluate(*args, &block)
self.class.evaluate(self, *args, &block)
self
end
end
end
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