src/condition-variables.lisp

   1 ;;;; -*- 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 &key timeout)
  22   (signal-error-if-condition-wait-timeout timeout)
  23   (check-type condition-variable condition-var)
  24   (setf (condition-var-active condition-variable) nil)
  25   (release-lock lock)
  26   (do ()
  27       ((when (condition-var-active condition-variable)
  28          (acquire-lock lock)
  29          t))
  30     (thread-yield))
  31   t)
  32
  33 (define-condition-wait-compiler-macro)
  34
  35 (defun condition-notify (condition-variable)
  36   (check-type condition-variable condition-var)
  37   (with-lock-held ((condition-var-lock condition-variable))
  38     (setf (condition-var-active condition-variable) t)))