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cs: fix retention of late will executors

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A late will executor must stay live as long as it has finalizations
registered.
This commit is contained in:
Matthew Flatt 2019-05-02 17:30:53 -06:00
parent 8f5f0a4330
commit 358764faac
1 changed files with 9 additions and 5 deletions
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14
racket/src/cs/rumble/will-executor.ss
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@ -14,16 +14,17 @@
(define-thread-local the-stubborn-will-stacks (make-weak-eq-hashtable)) (define-thread-local the-stubborn-will-stacks (make-weak-eq-hashtable))
(define-record-type (will-executor create-will-executor will-executor?) (define-record-type (will-executor create-will-executor will-executor?)
(fields guardian will-stacks (mutable ready) notify)) (fields guardian will-stacks (mutable ready) notify stubborn?))
(define (make-will-executor notify) (define (make-will-executor notify)
(create-will-executor the-will-guardian the-will-stacks '() notify)) (create-will-executor the-will-guardian the-will-stacks '() notify #f))
;; A "stubborn" will executor corresponds to an ordered guardian. It ;; A "stubborn" will executor corresponds to an ordered guardian. It
;; doesn't need to make any guarantees about order for multiple ;; doesn't need to make any guarantees about order for multiple
;; registrations, so use a fresh guardian each time. ;; registrations, so use a fresh guardian each time.
;; A stubborn executor is treated a little specially in `will-register`.
(define (make-stubborn-will-executor notify) (define (make-stubborn-will-executor notify)
(create-will-executor the-stubborn-will-guardian the-stubborn-will-stacks '() notify)) (create-will-executor the-stubborn-will-guardian the-stubborn-will-stacks '() notify #t))
(define/who (will-register executor v proc) (define/who (will-register executor v proc)
(check who will-executor? executor) (check who will-executor? executor)
@ -34,8 +35,11 @@
;; unreachable, then we can drop the finalizer procedure. That ;; unreachable, then we can drop the finalizer procedure. That
;; pattern prevents unbreakable cycles by an untrusted process ;; pattern prevents unbreakable cycles by an untrusted process
;; that has no access to a will executor that outlives the ;; that has no access to a will executor that outlives the
;; process. ;; process. But stubborn will executors persist as long as
[e+proc (ephemeron-cons executor proc)]) ;; a will is registered.
[e+proc (if (will-executor-stubborn? executor)
(cons executor proc)
(ephemeron-cons executor proc))])
(hashtable-set! (will-executor-will-stacks executor) v (cons e+proc l)) (hashtable-set! (will-executor-will-stacks executor) v (cons e+proc l))
(when (null? l) (when (null? l)
((will-executor-guardian executor) v))) ((will-executor-guardian executor) v)))