diff options
Diffstat (limited to 'lib/singleton.rb')
| -rw-r--r-- | lib/singleton.rb | 110 |
1 files changed, 57 insertions, 53 deletions
diff --git a/lib/singleton.rb b/lib/singleton.rb index 3ab048f5a3..404eaf7101 100644 --- a/lib/singleton.rb +++ b/lib/singleton.rb @@ -44,60 +44,64 @@ # of a previous state of ``the instance'' - see third example. # module Singleton - def Singleton.included (klass) - # should this be checked? - # raise TypeError.new "..." if klass.type == Module - class << klass - def inherited(sub_klass) - # @__instance__ takes on one of the following values - # * nil - before (and after a failed) creation - # * false - during creation - # * sub_class instance - after a successful creation - sub_klass.instance_eval { @__instance__ = nil } - def sub_klass.instance - unless @__instance__.nil? - # is the extra flexiblity having the hook method - # _wait() around ever useful? - _wait() - # check for instance creation - return @__instance__ if @__instance__ - end - Thread.critical = true - unless @__instance__ - @__instance__ = false - Thread.critical = false - begin - @__instance__ = new - ensure - if @__instance__ - define_method(:instance) {@__instance__ } - else - # failed instance creation - @__instance__ = nil - end - end - else - Thread.critical = false - end - return @__instance__ - end - end - def _load(str) - instance - end - def _wait - sleep(0.05) while false.equal?(@__instance__) - end - private :new, :allocate - # hook methods are also marked private - private :_load,:_wait - end - klass.inherited klass - end - private - def _dump(depth) - return "" + def Singleton.included (klass) + # should this be checked? + # raise TypeError.new "..." if klass.type == Module + klass.module_eval { + undef_method :clone + undef_method :dup + } + class << klass + def inherited(sub_klass) + # @__instance__ takes on one of the following values + # * nil - before (and after a failed) creation + # * false - during creation + # * sub_class instance - after a successful creation + sub_klass.instance_eval { @__instance__ = nil } + def sub_klass.instance + unless @__instance__.nil? + # is the extra flexiblity having the hook method + # _wait() around ever useful? + _wait() + # check for instance creation + return @__instance__ if @__instance__ + end + Thread.critical = true + unless @__instance__ + @__instance__ = false + Thread.critical = false + begin + @__instance__ = new + ensure + if @__instance__ + define_method(:instance) {@__instance__ } + else + # failed instance creation + @__instance__ = nil + end + end + else + Thread.critical = false + end + return @__instance__ + end + end + def _load(str) + instance + end + def _wait + sleep(0.05) while false.equal?(@__instance__) + end + private :new, :allocate + # hook methods are also marked private + private :_load,:_wait end + klass.inherited klass + end + private + def _dump(depth) + return "" + end end if __FILE__ == $0 |