source: branches/home/psmith/restructure/src/protocol/yarpc/yarpc-state-machine.lisp

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Copyright (c) 2007
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(in-package :nio-yarpc)

(declaim (optimize (debug 3) (speed 3) (space 0)))

;; YetAnotherRPC state machine
;;
;; A server that processes remote procedure calls and returns results
;;
(defclass yarpc-state-machine (state-machine)
  (
   (result-queue :initform (nio-utils:concurrent-queue)
                 :accessor result-queue
                 :documentation "The queue used to return results from an external thread to the nio thread")))

(defparameter job-queue (nio-utils:concurrent-queue)
  "The queue used to hand off work from the NIO thread to an external thread for execution")

(defparameter yarpc-pf (yarpc-packet-factory))

(defmethod get-packet-factory((sm yarpc-state-machine))
  yarpc-pf)

(defmethod print-object ((sm yarpc-state-machine) stream)
  (format stream "#<YARPC-STATE-MACHINE ~A >" (call-next-method sm nil)))

(defconstant STATE-INITIALISED 0)
(defconstant STATE-SEND-RESPONSE 1)

(defun run-job(&key (blocking t))
#+nio-debug  (format-log t "yarpc-state-machine:run-job - Server toplevel waiting for job~%")
  (let ((server-job (nio-utils:take nio-yarpc:job-queue :blocking-call blocking)))
    (when server-job 
      (destructuring-bind (job request-id result-queue) server-job
#+nio-debug     (format-log t "yarpc-state-machine:run-job - Server received job ~A~%" job)
        (nio-utils:add result-queue (list request-id (nio-yarpc:execute-call job)))))))

(defmethod process-timeout((sm yarpc-state-machine)))

(defmethod process-outgoing-packet((sm yarpc-state-machine))
#+nio-debug2  (format-log t "yarpc-state-machine:process-outgoing-packet - called, polling the results-queue ~%" )
  (let ((server-job (nio-utils:take (result-queue sm) :blocking-call nil)))
    (when server-job
      (destructuring-bind (request-id result) server-job
#+nio-debug     (format-log t "yarpc-state-machine:process-outgoing-packet - got :request-id ~A result ~A ~%" request-id result)
        (method-response-packet result :request-id request-id)))))

;Process a call method packet by placing it in the job-queue
(defmethod process-incoming-packet ((sm yarpc-state-machine) (call call-method-packet))
#+nio-debug  (format-log t "yarpc-state-machine:process-incoming-packet - called :sm ~A :packet ~A~%" sm call)
  (nio-utils:add job-queue (list (call-string call) (request-id call) (result-queue sm))))



;;TODO move somewhere suitable

(defparameter *remote-fns* nil)

(defun register-remote-fn(name)
    (push name *remote-fns*))

(defmacro defremote (name args &rest body)
  `(progn 
     (defun ,name (,@args) ,@body)
     (register-remote-fn #',name)))

(defremote test-rpc-list()
  (list 3 "as" 's (code-char #x2211)))

(defremote test-rpc-string(a b c)
  (format nil "response - ~A ~A ~A ~A~%" a b c (code-char #x2211)))

(define-condition authorization-error (error) ())

(defun execute-call (call-string)
  (handler-case
      (let* ((rpc-call-list (read-from-string call-string ))
             (fn (member (symbol-function (first rpc-call-list)) *remote-fns* )))
#+nio-debug     (format-log t "yarpc-state-machine:execute-call - fn ~A authorised? : ~A~%" (symbol-function (first rpc-call-list)) fn)
        (if fn
            (eval rpc-call-list)
            (error 'authorization-error)))
    (reader-error (re) (format-log t "yarpc-state-machine:execute-call - reader error on call-string ~A ~%" re))))

;;end move TODO





;  (handler-case
;    (let ((result (execute-call (call-string call))))
;      (when result 
;       (let ((response-packet (progn 
;                                  (setf state STATE-SEND-RESPONSE)
;                                  (queue-outgoing-packet sm (method-response-packet result)))))
;          t)))
;    (reader-error (re) (format t "No such function ~A~%" (call-string call)))
;    (authorization-error (ae) (format t "Function not declared with defremote ~A~%" (call-string call))))