factor/basis/concurrency/count-downs/count-downs.factor

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Factor
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! Copyright (C) 2008 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: dlists kernel math concurrency.promises
concurrency.mailboxes accessors fry ;
IN: concurrency.count-downs
! http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/CountDownLatch.html
TUPLE: count-down-tuple n promise ;
: count-down-check ( count-down -- )
dup n>> zero? [ t swap promise>> fulfill ] [ drop ] if ;
ERROR: invalid-count-down-count count ;
: <count-down> ( n -- count-down )
dup 0 < [ invalid-count-down-count ] when
<promise> \ count-down-tuple boa
dup count-down-check ;
ERROR: count-down-already-done ;
: count-down ( count-down -- )
dup n>> dup zero?
[ count-down-already-done ]
[ 1 - >>n count-down-check ] if ;
: await-timeout ( count-down timeout -- )
[ promise>> ] dip ?promise-timeout ?linked t assert= ;
: await ( count-down -- )
f await-timeout ;
: spawn-stage ( quot count-down -- )
[ '[ @ _ count-down ] ] keep
"Count down stage"
swap promise>> mailbox>> spawn-linked-to drop ;