typed-racket/collects/unstable/logging.rkt
Vincent St-Amour 2acacf1284 Add with-logging-to-port to unstable.
original commit: 8d96133681a1302c9395485b969049c9a072d552
2011-05-31 19:14:38 -04:00

39 lines
1.6 KiB
Racket

#lang racket/base
(require racket/contract)
(define (with-logging-to-port port level proc)
(let* ([logger (make-logger #f (current-logger))]
[receiver (make-log-receiver logger level)]
[stop-chan (make-channel)]
[t (thread (lambda ()
(define (output-event l)
(displayln (vector-ref l 1) ; actual message
port))
(define (clear-events)
(let ([l (sync/timeout 0 receiver)])
(when l ; still something to read
(output-event l)
(clear-events))))
(let loop ()
(let ([l (sync receiver stop-chan)])
(cond [(eq? l 'stop)
;; we received all the events we were supposed
;; to get, read them all (w/o waiting), then
;; stop
(clear-events)]
[else ; keep going
(output-event l)
(loop)])))))])
(begin0
(parameterize ([current-logger logger])
(proc))
(channel-put stop-chan 'stop) ; stop the receiver thread
(thread-wait t))))
(provide/contract [with-logging-to-port
(-> output-port?
(or/c 'fatal 'error 'warning 'info 'debug)
(-> any)
any)])