49 lines
1.4 KiB
Racket
49 lines
1.4 KiB
Racket
#lang racket/base
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(require racket/match)
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(require "codec.rkt")
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(require "os-big-bang.rkt")
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(require "os-udp.rkt")
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(provide (struct-out set-timer)
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(struct-out timer-expired)
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timer-driver
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timer-relay)
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(struct set-timer (label msecs relative?) #:prefab)
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(struct timer-expired (label msecs) #:prefab)
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;; Something like this should be part of racket
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(define (timer-evt msecs relative?)
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(wrap-evt (alarm-evt (if relative? (+ (current-inexact-milliseconds) msecs) msecs))
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(lambda (_) (current-inexact-milliseconds))))
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(define (timer-driver [self-id 'timer-driver])
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(os-big-bang 'no-state
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(subscribe 'timer-setter
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(message-handlers w
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[(set-timer label msecs relative?)
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(transition w
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(subscribe label
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(ground-message-handler w
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[((list self-id label)
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(timer-evt msecs relative?)
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=> now)
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(transition w
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(unsubscribe label)
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(send-message (timer-expired label now)))])))]))))
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(define (timer-relay [self-id 'timer-relay])
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(os-big-bang 'no-state
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(subscribe 'timer-relay
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(message-handlers w
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[(set-timer label msecs relative?)
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(transition w
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(send-meta-message (set-timer (list self-id label) msecs relative?))
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(subscribe label
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(meta-message-handlers w
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[(timer-expired (list (== self-id) (== label)) now)
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(transition w
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(unsubscribe label)
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(send-message (timer-expired label now)))])))]))))
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