extra/concurrency/count-downs/count-downs.factor

   1 ! Copyright (C) 2008 Slava Pestov.\r
   2 ! See http://factorcode.org/license.txt for BSD license.\r
   3 USING: dlists kernel math concurrency.promises\r
   4 concurrency.mailboxes debugger accessors ;\r
   5 IN: concurrency.count-downs\r
   6 \r
   7 ! http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/CountDownLatch.html\r
   8 \r
   9 TUPLE: count-down n promise ;\r
  10 \r
  11 : count-down-check ( count-down -- )\r
  12     dup n>> zero? [ t swap promise>> fulfill ] [ drop ] if ;\r
  13 \r
  14 : <count-down> ( n -- count-down )\r
  15     dup 0 < [ "Invalid count for count down" throw ] when\r
  16     <promise> \ count-down boa\r
  17     dup count-down-check ;\r
  18 \r
  19 : count-down ( count-down -- )\r
  20     dup n>> dup zero?\r
  21     [ "Count down already done" throw ]\r
  22     [ 1- >>n count-down-check ] if ;\r
  23 \r
  24 : await-timeout ( count-down timeout -- )\r
  25     >r promise>> r> ?promise-timeout ?linked t assert= ;\r
  26 \r
  27 : await ( count-down -- )\r
  28     f await-timeout ;\r
  29 \r
  30 : spawn-stage ( quot count-down -- )\r
  31     [ [ count-down ] curry compose ] keep\r
  32     "Count down stage"\r
  33     swap promise>> mailbox>> spawn-linked-to drop ;\r