factor/extra/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 ;
IN: concurrency.count-downs
! http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/CountDownLatch.html
TUPLE: count-down n promise ;
: count-down-check ( count-down -- )
dup count-down-n zero? [
t swap count-down-promise fulfill
] [ drop ] if ;
: <count-down> ( n -- count-down )
dup 0 < [ "Invalid count for count down" throw ] when
<promise> \ count-down construct-boa
dup count-down-check ;
: count-down ( count-down -- )
dup count-down-n dup zero? [
"Count down already done" throw
] [
1- over set-count-down-n
count-down-check
] if ;
: await-timeout ( count-down timeout -- )
>r count-down-promise r> ?promise-timeout drop ;
: await ( count-down -- )
f await-timeout ;
: spawn-stage ( quot count-down -- )
[ [ count-down ] curry compose ] keep
"Count down stage"
swap count-down-promise
promise-mailbox spawn-linked-to drop ;