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;;; -*- indent-tabs-mode: nil; coding: latin-1-unix -*-
;;;
;;; swank-rpc.lisp -- Pass remote calls and responses between lisp systems.
;;;
;;; Created 2010, Terje Norderhaug <terje@in-progress.com>
;;;
;;; This code has been placed in the Public Domain. All warranties
;;; are disclaimed.
;;;
;;(declaim (optimize (debug 3) (safety 3) (speed 2)))
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(defpackage #:swank-rpc
(:use :cl)
(:export
#:read-message
#:swank-reader-error
#:swank-reader-error.packet
#:swank-reader-error.cause
#:write-message))
(in-package :swank-rpc)
;;;;; Input
(define-condition swank-reader-error (reader-error)
((packet :type string :initarg :packet
:reader swank-reader-error.packet)
(cause :type reader-error :initarg :cause
:reader swank-reader-error.cause)))
(defun read-message (stream package)
(let ((packet (read-packet stream)))
(handler-case (values (read-form packet package))
(reader-error (c)
(error 'swank-reader-error
:packet packet :cause c)))))
(defun read-packet (stream)
(let* ((length (parse-header stream))
(octets (read-chunk stream length)))
(handler-case (swank-backend:utf8-to-string octets)
(error (c)
(break "In read-packet error handler")
(error 'swank-reader-error
:packet (asciify octets)
:cause c)))))
(defun asciify (packet)
(with-output-to-string (*standard-output*)
(loop for code across (etypecase packet
(string (map 'vector #'char-code packet))
(vector packet))
do (cond ((<= code #x7f) (write-char (code-char code)))
(t (format t "\\x~x" code))))))
(defun parse-header (stream)
(parse-integer (map 'string #'code-char (read-chunk stream 6))
:radix 16))
(defun read-chunk (stream length)
(let* ((buffer (make-array length :element-type '(unsigned-byte 8)))
(count (read-sequence buffer stream)))
(cond ((= count length)
buffer)
((zerop count)
(error 'end-of-file :stream stream))
(t
(error "Short read: length=~D count=~D" length count)))))
;; FIXME: no one ever tested this and will probably not work.
(defparameter *validate-input* nil
"Set to true to require input that strictly conforms to the protocol")
(defun read-form (string package)
(with-standard-io-syntax
(let ((*package* package))
(if *validate-input*
(validating-read string)
(read-from-string string)))))
(defun validating-read (string)
(with-input-from-string (*standard-input* string)
(simple-read)))
(defun simple-read ()
"Read a form that conforms to the protocol, otherwise signal an error."
(let ((c (read-char)))
(case c
(#\" (with-output-to-string (*standard-output*)
(loop for c = (read-char) do
(case c
(#\" (return))
(#\\ (write-char (read-char)))
(t (write-char c))))))
(#\( (loop collect (simple-read)
while (ecase (read-char)
(#\) nil)
(#\space t))))
(#\' `(quote ,(simple-read)))
(t (let ((string (with-output-to-string (*standard-output*)
(loop for ch = c then (read-char nil nil) do
(case ch
((nil) (return))
(#\\ (write-char (read-char)))
((#\space #\)) (unread-char ch)(return))
(t (write-char ch)))))))
(cond ((digit-char-p c) (parse-integer string))
((intern string))))))))
;;;;; Output
(defun write-message (message package stream)
(let* ((string (prin1-to-string-for-emacs message package))
(octets (handler-case (swank-backend:string-to-utf8 string)
(error (c) (encoding-error c string))))
(length (length octets)))
(write-header stream length)
(write-sequence octets stream)
(finish-output stream)))
;; FIXME: for now just tell emacs that we and an encoding problem.
(defun encoding-error (condition string)
(swank-backend:string-to-utf8
(prin1-to-string-for-emacs
`(:reader-error
,(asciify string)
,(format nil "Error during string-to-utf8: ~a"
(or (ignore-errors (asciify (princ-to-string condition)))
(asciify (princ-to-string (type-of condition))))))
(find-package :cl))))
(defun write-header (stream length)
(declare (type (unsigned-byte 24) length))
;;(format *trace-output* "length: ~d (#x~x)~%" length length)
(loop for c across (format nil "~6,'0x" length)
do (write-byte (char-code c) stream)))
(defun prin1-to-string-for-emacs (object package)
(with-standard-io-syntax
(let ((*print-case* :downcase)
(*print-readably* nil)
(*print-pretty* nil)
(*package* package))
(prin1-to-string object))))
#| TEST/DEMO:
(defparameter *transport*
(with-output-to-string (out)
(write-message '(:message (hello "world")) *package* out)
(write-message '(:return 5) *package* out)
(write-message '(:emacs-rex NIL) *package* out)))
*transport*
(with-input-from-string (in *transport*)
(loop while (peek-char T in NIL)
collect (read-message in *package*)))
|#