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;;; **********************************************************************
;;; This code was written as part of the CMU Common Lisp project at
;;; Carnegie Mellon University, and has been placed in the public domain.
;;;
(ext:file-comment
"$Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/code/fd-stream.lisp,v 1.82 2005/02/21 17:14:28 rtoy Exp $")
;;; **********************************************************************
;;;
;;; Streams for UNIX file descriptors.
;;;
;;; Written by William Lott, July 1989 - January 1990.
;;; Some tuning by Rob MacLachlan.
;;;
;;; **********************************************************************
(in-package "SYSTEM")
(export '(fd-stream fd-stream-p fd-stream-fd make-fd-stream
io-timeout beep *beep-function* output-raw-bytes
*tty* *stdin* *stdout* *stderr*))
(in-package "EXTENSIONS")
(export '(*backup-extension*))
(in-package "LISP")
(export '(file-stream file-string-length))
;;;; Buffer manipulation routines.
(defvar *available-buffers* ()
"List of available buffers. Each buffer is an sap pointing to
bytes-per-buffer of memory.")
(defconstant bytes-per-buffer (* 4 1024)
"Number of bytes per buffer.")
;; This limit is rather arbitrary
(defconstant max-stream-element-size 1024
"The maximum supported byte size for a stream element-type.")
;;; Returns the next available buffer, creating one if necessary.
;;;
(defun next-available-buffer ()
(if *available-buffers*
(pop *available-buffers*)
(allocate-system-memory bytes-per-buffer)))
;;;; Superclass defined by the ANSI Spec
(defstruct (file-stream
(:include lisp-stream)
(:constructor nil)
(:copier nil)))
(defstruct (fd-stream
(:print-function %print-fd-stream)
(:constructor %make-fd-stream)
(misc #'fd-stream-misc-routine)))
(name nil) ; The name of this stream
(file nil) ; The file this stream is for
;;
;; The backup file namestring for the old file, for :if-exists :rename or
;; :rename-and-delete.
(original nil :type (or simple-string null))
;;
;;; Number of bytes per element.
(element-size 1 :type index)
(element-type 'base-char) ; The type of element being transfered.
;;
;; Controls when the output buffer is flushed.
(buffering :full :type (member :full :line :none))
;;
;; Character position if known.
(char-pos nil :type (or index null))
;;
;; T if input is waiting on FD. :EOF if we hit EOF.
(listen nil :type (member nil t :eof))
;;
(ibuf-sap nil :type (or system-area-pointer null))
(ibuf-length nil :type (or index null))
(ibuf-head 0 :type index)
(ibuf-tail 0 :type index)
(obuf-sap nil :type (or system-area-pointer null))
(obuf-length nil :type (or index null))
(obuf-tail 0 :type index)
;; Output flushed, but not written due to non-blocking io.
(output-later nil)
(handler nil)
;;
;; Timeout specified for this stream, or NIL if none.
(timeout nil :type (or index null))
;;
;; Pathname of the file this stream is opened to (returned by PATHNAME.)
(pathname nil :type (or pathname null)))
(declare (ignore depth) (stream stream))
(format stream "#<Stream for ~A>"
(fd-stream-name fd-stream)))
(define-condition io-timeout (stream-error)
((direction :reader io-timeout-direction :initarg :direction))
(:report
(lambda (condition stream)
(format stream "Timeout ~(~A~)ing ~S."
(io-timeout-direction condition)
(stream-error-stream condition)))))
;;;; Output routines and related noise.
(defvar *output-routines* ()
"List of all available output routines. Each element is a list of the
element-type output, the kind of buffering, the function name, and the number
of bytes per element.")
;;; DO-OUTPUT-LATER -- internal
;;;
;;; Called by the server when we can write to the given file descriptor.
;;; Attempt to write the data again. If it worked, remove the data from the
;;; output-later list. If it didn't work, something is wrong.
;;;
(defun do-output-later (stream)
(let* ((stuff (pop (fd-stream-output-later stream)))
(base (car stuff))
(start (cadr stuff))
(end (caddr stuff))
(declare (type index start end length))
(error "Write would have blocked, but SERVER told us to go.")
(error "While writing ~S: ~A"
((eql count length) ; Hot damn, it worked.
(when reuse-sap
(push base *available-buffers*)))
(fd-stream-output-later stream))))))
(unless (fd-stream-output-later stream)
(system:remove-fd-handler (fd-stream-handler stream))
(setf (fd-stream-handler stream) nil)))
;;; OUTPUT-LATER -- internal
;;;
;;; Arrange to output the string when we can write on the file descriptor.
(defun output-later (stream base start end reuse-sap)
(cond ((null (fd-stream-output-later stream))
(setf (fd-stream-output-later stream)
(list (list base start end reuse-sap)))
(setf (fd-stream-handler stream)
(system:add-fd-handler (fd-stream-fd stream)
:output
#'(lambda (fd)
(declare (ignore fd))
(do-output-later stream)))))
(t
(nconc (fd-stream-output-later stream)
(list (list base start end reuse-sap)))))
(when reuse-sap
(setf (fd-stream-obuf-sap stream) new-buffer)
(setf (fd-stream-obuf-length stream) bytes-per-buffer))))
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