60 lines
2.0 KiB
Racket
60 lines
2.0 KiB
Racket
#lang racket/base
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(require racket/set)
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(require racket/match)
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(require racket/list)
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(require "core.rkt")
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(require "gestalt.rkt")
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(provide (struct-out event)
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run-ground)
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(struct event (descriptor values) #:prefab)
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(define (event-handler descriptor)
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(handle-evt descriptor (lambda vs (send (event descriptor vs)))))
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(define event-projection (compile-gestalt-projection (event ?! ?)))
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(define (extract-active-events gestalt)
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(define es (matcher-key-set (gestalt-project gestalt 0 0 #f event-projection)))
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;; TODO: how should the following error be handled, ideally?
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;; In principle, security restrictions should make it impossible.
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;; But absent those, what should be done? Should an offending
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;; process be identified and terminated?
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(when (not es) (error 'extract-active-events "User program subscribed to wildcard event"))
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(for/list [(ev (in-set es))]
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(match-define (vector e) ev)
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(event-handler e)))
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(define idle-handler
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(handle-evt (system-idle-evt) (lambda _ #f)))
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(define (run-ground . boot-actions)
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(let await-interrupt ((inert? #f) (p (spawn-world boot-actions)) (active-events '()))
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(define event-list (if inert?
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active-events
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(cons idle-handler active-events)))
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(if (null? event-list)
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(begin (log-info "run-ground: Terminating because inert")
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(void))
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(let ((e (apply sync event-list)))
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(match (deliver-event e -2 p)
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[#f ;; inert
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(await-interrupt #t p active-events)]
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[(transition new-state actions)
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(let process-actions ((actions (flatten actions)) (active-events active-events))
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(match actions
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['()
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(await-interrupt #f (struct-copy process p [state new-state]) active-events)]
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[(cons a actions)
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(match a
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[(routing-update gestalt)
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(process-actions actions (extract-active-events gestalt))]
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[(quit)
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(log-info "run-ground: Terminating by request")
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(void)]
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[_
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(log-warning "run-ground: ignoring useless meta-action ~v" a)
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(process-actions actions active-events)])]))])))))
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