;;;; cl-scopes/util/async - utilities for asynchronous (concurrent / parallel) operations

(defpackage :scopes/util/async
  (:use :common-lisp)
  (:local-nicknames (:lp :lparallel)
                    (:lpq :lparallel.queue))
  (:export #:init #:finish #:make-ch #:make-mb #:rcv #:try-rcv #:snd 
           #:submit-task #:receive-result #:try-receive-result))

(in-package :scopes/util/async)

;;;; general definitions (lparallel wrappers)

(defun init ()
  (when (null lp:*kernel*)
    (format t "async:init ~a ~%" 
             (setf lp:*kernel* (lp:make-kernel (serapeum:count-cpus))))))

(defun finish ()
  (when lp:*kernel*
    (lp:end-kernel)))

;;;; higher-level mailbox / task / channel combination

(defclass mailbox ()
  ((queue :reader queue :initform (lpq:make-queue))
   (channel :reader channel :initform (lp:make-channel))))

(defun make-mb ()
  (make-instance 'mailbox))

(defun rcv (mb)
  (lpq:pop-queue (queue mb)))

(defun try-rcv (mb)
  (lpq:peek-queue (queue mb)))

(defun snd (mb msg)
  (lpq:push-queue msg (queue mb)))

(defun submit-task (mb job)
  (lp:submit-task (channel mb) job))

(defun receive-result (mb)
  (lp:receive-result (channel mb)))

(defun try-receive-result (mb)
  (lp:try-receive-result (channel mb)))