source: branches/home/psmith/restructure/src/io/nodes.lisp

#|
Copyright (c) 2007
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(in-package :nio)

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


;;concept of a remote socket with properties e.g. stats, connection attempts etc
(defclass node()
  ((family :initform :unknown :initarg :family)
   (remote-host :initarg :remote-host
                :initform nil
                :accessor remote-host)
   (remote-port :initarg :remote-port
                :initform nil
                :accessor remote-port)
   (last-connect-attempt :initform nil
                         :accessor last-connect-attempt
                         :documentation "Time we last attempted a connection")
   (retry-delay :initform 60
                :accessor retry-delay
                :documentation "The delay to wait (in secs) after the last-connection-attempt before trying to connect again (10 mins)")
   (active-conn :initform nil
                :accessor active-conn
                :documentation "If we are connected to this remote socket this is set to the SM")))

(defun node(host port)
  (make-instance 'node :remote-host host :remote-port port))

;(node-from-socket-repn "192.168.1.1:1234")
(defun node-from-socket-repn(socket)
  (let ((colon-idx (search ":" socket)))
    (if colon-idx
        (node (subseq socket 0 colon-idx) (parse-integer (subseq socket (+ colon-idx 1))))
        (error 'parse-error))))


(defmethod print-object ((a-node node) stream)
  (with-slots (remote-host remote-port last-connect-attempt retry-delay active-conn) a-node
    (format stream "#<NODE :remote-host ~A :remote-port ~A :last-connect-attempt ~A :retry-delay ~A :active-conn ~A>" 
            remote-host remote-port last-connect-attempt retry-delay active-conn)))


(defparameter *nodes-list* nil
  "List of nodes to connect to")

(defun load-nodes (filename)
  (with-open-file (stream filename)
    (loop for line = (read-line stream nil nil) do
         (push (node-from-socket-repn line) *nodes-list*))))


;;returns floating point (high-res) next allowed connect time
(defun get-next-allowed-connect-time(node)
  (if (null (last-connect-attempt node))
      (get-universal-high-res)
      (+ (last-connect-attempt node) (retry-delay node))))

(defun allowed-to-connect(node)
  (if (null (last-connect-attempt node))
      t
      (and (not (active-conn node)) (< (+ (last-connect-attempt node) (retry-delay node))  (get-universal-high-res)))))

(defun update-last-connect-attempt(node)
  (setf (last-connect-attempt node) (get-universal-high-res)))

;;iterates over the nodes list looking for nodes that are ready to be connected to
;;i.e. the SM is null and the next-allowed-connect time has expired
(defmacro with-connect-ready-nodes ((node) &rest body)
  `(dolist (,node *nodes-list*)
     (when (allowed-to-connect ,node) ,@body)))


(defmacro with-connected-nodes ((node) &rest body)
  `(dolist (,node *nodes-list*)
     (when (active-conn ,node) ,@body)))

(defun connected-nodes-count()
  (let ((count 0))
    (with-connected-nodes (node)
      (incf count))
    count))