477 lines
15 KiB
Scheme
477 lines
15 KiB
Scheme
;;; A Unix file port system to completely replace S48 file ports.
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;;; We use S48 extensible ports.
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;;; Copyright (c) 1993 by Olin Shivers.
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(define-record fdport-data
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channel
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revealed)
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(define max-fdport 255)
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; This stuff is _weak_.
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; Vector of weak pointers mapping fd -> fdport.
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(define (weak-vector-set! vector number set-me)
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(vector-set! vector number (make-weak-pointer set-me)))
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(define (weak-vector-ref vector number)
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(let ((ref (vector-ref vector number)))
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(if (weak-pointer? ref) (weak-pointer-ref ref) ref)))
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(define (strengthen-weak-vector-ref vector number)
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(vector-set! vector number (weak-vector-ref vector number)))
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(define (weaken-weak-vector-ref vector number)
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(weak-vector-set! vector number (weak-vector-ref vector number)))
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(define fdports (make-vector max-fdport #f))
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(define (install-fdport fdport)
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(let* ((fdport* (fdport-data fdport))
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(ch (fdport-data:channel fdport*))
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(ch-number (channel-os-index ch)))
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(if (fdport-data:revealed fdport*)
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(vector-set! fdports ch-number fdport)
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(weak-vector-set! fdports ch-number fdport))))
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(define (maybe-fdes->port fdes)
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(weak-vector-ref fdports fdes))
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;Hmm... these shouldn't be necessary. But still.
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;Fake defrec routines for backwards compatibility.
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(define (fdport-data:fd fdport*)
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(channel-os-index (fdport-data:channel fdport*)))
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(define (fdport-data:closed? fdport*)
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(eq? (channel-status (fdport-data:channel fdport*))
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(enum channel-status-option closed)))
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;Arbitrary, for now.
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(define buffer-size 255)
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(define open-fdchannel open-channel)
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(define (make-input-fdchannel fd)
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(open-fdchannel fd (enum channel-status-option input)))
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(define (make-output-fdchannel fd)
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(open-fdchannel fd (enum channel-status-option output)))
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;The two following routines are to build ports from stdin and stdout channels.
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(define (channel-port->input-fdport channel-port)
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(let ((p (make-input-port input-fdport-handler
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(make-fdport-data (channel-cell-ref (port-data channel-port)) 1)
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(make-code-vector buffer-size 0) 0 0)))
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(obtain-port-lock channel-port)
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(set-port-lock! p (port-lock channel-port))
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(set-port-locked?! p (port-locked? channel-port))
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(install-fdport p)
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(release-port-lock channel-port)
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p))
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(define (channel-port->output-fdport channel-port)
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(let ((p (make-output-port output-fdport-handler
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(make-fdport-data (channel-cell-ref(port-data channel-port)) 1)
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(make-code-vector buffer-size 0) 0 buffer-size)))
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(obtain-port-lock channel-port)
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(set-port-lock! p (port-lock channel-port))
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(set-port-locked?! p (port-locked? channel-port))
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(install-fdport p)
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(periodically-force-output! p)
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(release-port-lock channel-port)
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p))
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(define (alloc-input-fdport fd revealed)
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(make-input-port input-fdport-handler
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(make-fdport-data (make-input-fdchannel fd) revealed)
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(make-code-vector buffer-size 0) 0 0))
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(define (alloc-output-fdport fd revealed)
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(make-output-port output-fdport-handler
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(make-fdport-data (make-output-fdchannel fd) revealed)
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(make-code-vector buffer-size 0) 0 buffer-size))
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(define (make-input-fdport fd revealed)
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(let ((p (alloc-input-fdport fd revealed)))
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(install-fdport p)
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p))
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(define (make-output-fdport fd revealed)
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(let ((p (alloc-output-fdport fd revealed)))
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(periodically-force-output! p)
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(install-fdport p)
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p))
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(define (fdport? x)
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(cond ((or (and (input-port? x) (port-data x))
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(and (output-port? x) (port-data x)))
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=> (lambda (d) (fdport-data? d)))
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(else #f)))
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(define fdport-null-method (lambda (x) x #f))
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(define null-func (lambda args #t))
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(define (close-fdport* fdport*)
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(vector-set! fdports (channel-os-index (fdport-data:channel fdport*)) #f)
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(close-channel (fdport-data:channel fdport*)))
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;The handlers drop straight through to the convenient channel routines.
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(define input-fdport-handler
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(make-port-handler
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(lambda (fdport*)
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(list 'input-fdport (fdport-data:channel fdport*)))
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close-fdport*
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(lambda (fdport* buffer start needed)
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(channel-read buffer start needed (fdport-data:channel fdport*)))
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(lambda (fdport* owner)
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(steal-channel! (fdport-data:channel fdport*) owner))))
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(define output-fdport-handler
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(make-port-handler
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(lambda (fdport*)
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(list 'output-fdport (fdport-data:channel fdport*)))
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close-fdport*
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(lambda (fdport* buffer start count)
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(channel-write buffer start count (fdport-data:channel fdport*)))
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(lambda (fdport* owner)
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(steal-channel! (fdport-data:channel fdport*) owner))))
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(define fdport-data port-data)
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; That was easy.
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(define (set-port-buffering port policy . maybe-size)
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(warn "JMG: use of set-port-buffering"))
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;;; Open & Close
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;;; ------------
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(define (open-file fname flags . maybe-mode)
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(let ((fd (apply open-fdes fname flags maybe-mode))
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(access (bitwise-and flags open/access-mask)))
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((if (or (= access open/read) (= access open/read+write))
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make-input-fdport
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make-output-fdport)
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fd 0)))
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(define (open-input-file fname . maybe-flags)
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(let ((flags (:optional maybe-flags 0)))
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(open-file fname (deposit-bit-field flags open/access-mask open/read))))
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(define (open-output-file fname . rest)
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(let* ((flags (if (pair? rest) (car rest)
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(bitwise-ior open/create open/truncate))) ; default
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(maybe-mode (if (null? rest) '() (cdr rest)))
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(flags (deposit-bit-field flags open/access-mask open/write)))
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(apply open-file fname flags maybe-mode)))
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;;; All these revealed-count-hacking procs have atomicity problems.
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;;; They need to run uninterrupted.
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;;; (port-locks should do the trick -df)
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;;; (what else has atomicity problems? -df)
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(define (increment-revealed-count port delta)
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(obtain-port-lock port)
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(let* ((data (fdport-data port))
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(count (fdport-data:revealed data))
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(newcount (+ count delta)))
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(set-fdport-data:revealed data newcount)
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(if (and (zero? count) (> newcount 0)) ; We just became revealed,
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(begin
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(strengthen-weak-vector-ref fdports (fdport-data:fd data))
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(%set-cloexec (fdport-data:fd data) #f)))); so don't close on exec().
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(release-port-lock port))
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(define (release-port-handle port)
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(check-arg fdport? port port->fdes)
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(obtain-port-lock port)
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(let* ((data (fdport-data port))
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(rev (fdport-data:revealed data)))
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(if (not (zero? rev))
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; (set-fdport-data:old-revealed data
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; (- (fdport-data:old-revealed data) 1))
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(let ((new-rev (- rev 1)))
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(set-fdport-data:revealed data new-rev)
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(if (zero? new-rev) ; We just became unrevealed, so
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(begin ; the fd can be closed on exec.
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(weaken-weak-vector-ref fdports (fdport-data:fd data))
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(%set-cloexec (fdport-data:fd data) #t))))))
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(release-port-lock port))
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(define (port-revealed port)
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(let ((count (fdport-data:revealed
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(fdport-data
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(check-arg fdport? port port-revealed)))))
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(and (not (zero? count)) count)))
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(define (fdes->port fd port-maker) ; local proc.
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(cond ((maybe-fdes->port fd) =>
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(lambda (p)
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(increment-revealed-count p 1)
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p))
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(else (port-maker fd 1))))
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(define (fdes->inport fd) (fdes->port fd make-input-fdport))
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(define (fdes->outport fd) (fdes->port fd make-output-fdport))
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(define (port->fdes port)
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(check-arg open-fdport? port port->fdes)
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(let ((data (fdport-data port)))
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(increment-revealed-count port 1)
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(fdport-data:fd data)))
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(define (call/fdes fd/port proc)
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(cond ((integer? fd/port)
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(proc fd/port))
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((fdport? fd/port)
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(let ((port fd/port))
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(dynamic-wind
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(lambda ()
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(if (not port) (error "Can't throw back into call/fdes.")))
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(lambda () (proc (port->fdes port)))
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(lambda ()
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(release-port-handle port)
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(set! port #f)))))
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(else (error "Not a file descriptor or fdport." fd/port))))
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;;; Don't mess with the revealed count in the port case
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;;; -- just sneakily grab the fdes and run.
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(define (sleazy-call/fdes fd/port proc)
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(proc (cond ((integer? fd/port) fd/port)
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((fdport? fd/port) (fdport-data:fd (fdport-data fd/port)))
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(else (error "Not a file descriptor or fdport." fd/port)))))
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;;; Random predicates and arg checkers
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;;; ----------------------------------
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(define (open-fdport-data? x)
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(and (fdport-data? x)
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(not (fdport-data:closed? x))))
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(define (open-fdport? x)
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(and (fdport? x) (or (open-output-port? x) (open-input-port? x))))
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(define (fdport-open? port)
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(check-arg fdport? port fdport-open?)
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(not (fdport-data:closed? (port-data port))))
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;;; Initialise the system
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;;; ---------------------
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;;; JMG: should be deprecated-proc
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(define error-output-port
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current-error-port)
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(define old-inport #f) ; Just because.
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(define old-outport #f)
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(define old-errport #f)
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(define (init-fdports!)
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(if (not (fdport? (current-input-port)))
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(set! old-inport (current-input-port)))
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(if (not (fdport? (current-output-port)))
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(set! old-outport (current-output-port)))
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(if (not (fdport? (current-error-port)))
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(set! old-errport (current-error-port)))
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(set-fluid! $current-input-port (channel-port->input-fdport (current-input-port)))
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(set-fluid! $current-output-port (channel-port->output-fdport (current-output-port)))
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(set-fluid! $current-error-port (channel-port->output-fdport (current-error-port)))
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(set-fluid! $current-noise-port (make-null-output-port)))
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;;; Generic port operations
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;;; -----------------------
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;;; (close-after port f)
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;;; Apply F to PORT. When F returns, close PORT, then return F's result.
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;;; Does nothing special if you throw out or throw in.
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(define (close-after port f)
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(receive vals (f port)
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(close port)
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(apply values vals)))
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(define (close port/fd)
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((cond ((integer? port/fd) close-fdes)
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((output-port? port/fd) close-output-port)
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((input-port? port/fd) close-input-port)
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(else (error "Not file-descriptor or port" port/fd))) port/fd))
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;;; If this fd has an associated input or output port,
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;;; move it to a new fd, freeing this one up.
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(define (evict-ports fd)
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(cond ((maybe-fdes->port fd) => ; Shouldn't bump the revealed count.
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(lambda (port)
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(%move-fdport (%dup fd) port 0)))))
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(define (%move-fdport fd port new-revealed)
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(obtain-port-lock port)
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(let* ((fdport* (fdport-data port))
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(ch (fdport-data:channel fdport*))
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(old-fd (channel-os-index ch))
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(old-vector-ref (vector-ref fdports old-fd)))
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(set-fdport-data:revealed fdport* new-revealed)
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(vector-set! fdports old-fd #f)
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(close-channel ch)
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(set-fdport-data:channel
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fdport*
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((if (input-port? port) make-input-fdchannel make-output-fdchannel) fd))
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(vector-set! fdports fd old-vector-ref)
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(%set-cloexec fd (not new-revealed)))
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(release-port-lock port)
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#f) ; JMG: It used to return #f on succes in 0.5.1, so we do the same
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(define (close-fdes fd)
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(evict-ports fd)
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(%close-fdes fd))
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(define (flush-fdport fdport)
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(check-arg fdport? fdport flush-fdport)
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(force-output fdport))
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(define (flush-all-ports)
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(let loop ((i 0))
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(if (< i max-fdport)
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(begin
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(let ((fdport (weak-vector-ref fdports i)))
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(if (and fdport (output-port? fdport) ) (flush-fdport fdport)))
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(loop (+ i 1))))))
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;;; Extend R4RS i/o ops to handle file descriptors.
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;;; -----------------------------------------------
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(define s48-char-ready? (structure-ref scheme char-ready?))
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(define s48-read-char (structure-ref scheme read-char))
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(define-simple-syntax
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(define-r4rs-input (name arg ...) stream s48name body ...)
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(define (name arg ... . maybe-i/o)
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(let ((stream (:optional maybe-i/o (current-input-port))))
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(cond ((input-port? stream) (s48name arg ... stream))
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((integer? stream) body ...)
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(else (error "Not a port or file descriptor" stream))))))
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(define-r4rs-input (char-ready?) input s48-char-ready?
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(%char-ready-fdes? input))
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(define-r4rs-input (read-char) input s48-read-char
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(read-fdes-char input))
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;structure refs changed to get reference from scheme -dalbertz
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(define s48-display (structure-ref scheme display))
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(define s48-newline (structure-ref scheme newline))
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(define s48-write (structure-ref scheme write))
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(define s48-write-char (structure-ref scheme write-char))
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(define s48-format (structure-ref formats format))
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(define s48-force-output (structure-ref i/o force-output))
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(define-simple-syntax
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(define-r4rs-output (name arg ...) stream s48name body ...)
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(define (name arg ... . maybe-i/o)
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(let ((stream (:optional maybe-i/o (current-output-port))))
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(cond ((output-port? stream) (s48name arg ... stream))
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((integer? stream) body ...)
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(else (error "Not a port or file descriptor" stream))))))
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;;; This one depends upon S48's string ports.
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(define-r4rs-output (display object) output s48-display
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(let ((sp (make-string-output-port)))
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(display object sp)
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(write-string (string-output-port-output sp) output)))
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(define-r4rs-output (newline) output s48-newline
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(write-fdes-char #\newline output))
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(define-r4rs-output (write object) output s48-write
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(let ((sp (make-string-output-port)))
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(write object sp)
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(write-string (string-output-port-output sp) output)))
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(define-r4rs-output (write-char char) output s48-write-char
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(write-fdes-char char output))
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;;; S48's force-output doesn't default to forcing (current-output-port).
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(define-r4rs-output (force-output) output s48-force-output
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(values)) ; Do nothing if applied to a file descriptor.
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(define (format dest cstring . args)
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(if (integer? dest)
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(write-string (apply s48-format #f cstring args) dest)
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(apply s48-format dest cstring args)))
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;;; with-current-foo-port procs
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;;; ---------------------------
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(define (with-current-input-port* port thunk)
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(let-fluid $current-input-port port thunk))
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(define (with-current-output-port* port thunk)
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(let-fluid $current-output-port port thunk))
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(define (with-current-error-port* port thunk)
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(let-fluid $current-error-port port thunk))
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(define-simple-syntax (with-current-input-port port body ...)
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(with-current-input-port* port (lambda () body ...)))
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(define-simple-syntax (with-current-output-port port body ...)
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(with-current-output-port* port (lambda () body ...)))
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(define-simple-syntax (with-current-error-port port body ...)
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(with-current-error-port* port (lambda () body ...)))
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;;; set-foo-port! procs
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;;; -------------------
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;;; Side-effecting variants of with-current-input-port* and friends.
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(define (set-current-input-port! port) (set-fluid! $current-input-port port))
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(define (set-current-output-port! port) (set-fluid! $current-output-port port))
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(define (set-current-error-port! port) (set-fluid! $current-error-port port))
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;;; call-with-foo-file with-foo-to-file
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;;; -----------------------------------
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;;; Copied straight from rts/port.scm, but re-defined in this module,
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;;; closed over my versions of open-input-file and open-output-file.
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(define (call-with-mumble-file open close)
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(lambda (string proc)
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(let ((port #f))
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(dynamic-wind (lambda ()
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(if port
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(warn "throwing back into a call-with-...put-file"
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string)
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(set! port (open string))))
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(lambda () (proc port))
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(lambda ()
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(if port
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(close port)))))))
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(define call-with-input-file
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(call-with-mumble-file open-input-file close-input-port))
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(define call-with-output-file
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(call-with-mumble-file open-output-file close-output-port))
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(define (with-input-from-file string thunk)
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(call-with-input-file string
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(lambda (port)
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(let-fluid $current-input-port port thunk))))
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|
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(define (with-output-to-file string thunk)
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(call-with-output-file string
|
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(lambda (port)
|
|
(let-fluid $current-output-port port thunk))))
|