src/condition-variables.lisp

   1 ;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; indent-tabs-mode: nil -*-
   2
   3 #|
   4 Copyright 2006, 2007 Greg Pfeil
   5
   6 Distributed under the MIT license (see LICENSE file)
   7 |#
   8
   9 (in-package #:bordeaux-threads)
  10
  11 ;;; This file provides a portable implementation of condition
  12 ;;; variables (given a working WITH-LOCK-HELD and THREAD-YIELD), and
  13 ;;; should be used if there is no condition variable implementation in
  14 ;;; the host Lisp.
  15
  16 (defstruct condition-var
  17   name
  18   lock
  19   active)
  20
  21 (defun condition-wait (condition-variable lock)
  22   (check-type condition-variable condition-var)
  23   (setf (condition-var-active condition-variable) nil)
  24   (release-lock lock)
  25   (do ()
  26       ((when (condition-var-active condition-variable)
  27          (acquire-lock lock)
  28          t))
  29     (thread-yield)))
  30
  31 (defun condition-notify (condition-variable)
  32   (check-type condition-variable condition-var)
  33   (with-lock-held ((condition-var-lock condition-variable))
  34     (setf (condition-var-active condition-variable) t)))