promise.rb in promise-0.3.1

- old
+ new

@@ -15,11 +15,11 @@
 #   x + 5     # => 15
 #
 class Promise < defined?(BasicObject) ? BasicObject : ::Object
   NOT_SET = ::Object.new.freeze
 
-  instance_methods.each { |m| undef_method m unless m.to_s =~ /__/ }
+  instance_methods.each { |m| undef_method m unless m =~ /^(__.*|object_id)$/ }
 
   ##
   # Creates a new promise.
   #
   # @example Lazily evaluate a database call
@@ -27,11 +27,11 @@
   #
   # @yield  [] The block to evaluate lazily.
   # @see    Kernel#promise
   def initialize(&block)
     if block.arity > 0
-      raise ArgumentError, "Cannot store a promise that requires an argument"
+      ::Kernel.raise ::ArgumentError, "Cannot store a promise that requires an argument"
     end
     @block  = block
     @mutex  = ::Mutex.new
     @result = NOT_SET
     @error  = NOT_SET
@@ -41,47 +41,54 @@
   # Force the evaluation of this promise immediately
   #
   # @return [Object]
   def __force__
     @mutex.synchronize do
-      if !__forced?
+      if @result.equal?(NOT_SET) && @error.equal?(NOT_SET)
         begin
           @result = @block.call
         rescue ::Exception => e
           @error = e
         end
       end
-    end unless __forced?
+    end if @result.equal?(NOT_SET) && @error.equal?(NOT_SET)
     # BasicObject won't send raise to Kernel
     @error.equal?(NOT_SET) ? @result : ::Kernel.raise(@error)
   end
   alias_method :force, :__force__
 
   ##
   # Does this promise support the given method?
   #
-  # @param  [Symbol]
-  # @return [true, false]
-  def respond_to?(method)
-    :__forced?.equal?(method) || :force.equal?(method) || :__force__.equal?(method) || __force__.respond_to?(method)
+  # @param  [Symbol, Boolean]
+  # @return [Boolean]
+  def respond_to?(method, include_all=false)
+    # If the promised object implements marshal_dump, Marshal will use it in
+    # preference to our _dump, so make sure that doesn't happen.
+    return false if :marshal_dump.equal?(method)
+
+    :_dump.equal?(method) ||  # for Marshal
+      :force.equal?(method) ||
+      :__force__.equal?(method) ||
+      __force__.respond_to?(method, include_all)
   end
 
   ##
-  # Returns true if klass.equal?(Promise) or the underlying block returns an
-  # instance of the given klass
+  # Method used by Marshal to serialize the object.  Forces evaluation.
   #
-  # @param [Class]
-  # @return [true, false]
-  def is_a?(klass)
-    klass.equal?(::Promise) || __force__.is_a?(klass)
+  # @param  [Integer] limit -- refer to Marshal doc
+  # @return [Object]
+  def _dump(limit)
+    ::Marshal.dump(__force__, limit)
   end
 
   ##
-  # Returns true if this promise has finished executing
+  # Method used by Marshal to deserialize the object.
   #
-  # @return [true, false]
-  def __forced?
-    !(@result.equal?(NOT_SET) && @error.equal?(NOT_SET))
+  # @param  [Object]
+  # @return [Promise]
+  def self._load(obj)
+    ::Marshal.load(obj)
   end
 
   private
 
   def method_missing(method, *args, &block)