[MacRuby-devel] [MacRuby] #477: Need GCD wrapper for dispatch_once

[MacRuby]

#477: Need GCD wrapper for dispatch_once
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 Reporter:  ernest.prabhakar@…          |       Owner:  lsansonetti@…        
     Type:  enhancement                 |      Status:  new                  
 Priority:  minor                       |   Milestone:  MacRuby 0.5          
Component:  MacRuby                     |    Keywords:                       
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Comment(by lsansonetti@…):

 The only way I see to implement this (without hacking the compiler) is to
 keep a static map of dispatch_once_t structures dynamically allocated on
 the fly and using the position of the caller within the stack frame as the
 unique id (key). However, accessing the table in a thread-safe manner will
 imply to keep it protected with a lock. I therefore wonder if all of this
 is really worth doing, since a call to Dispatch.once will be costlier than
 expected, and very similar to the following pure-Ruby code (which should
 even run faster):

 {{{
   @lock = Mutex.new
   ..
   @lock.synchronize do
     @called ||= false
     unless @called
       do_stuff
       @called = true
     end
   end
 }}}

-- 
Ticket URL: <http://www.macruby.org/trac/ticket/477#comment:6>
MacRuby <http://macruby.org/>