;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; indent-tabs-mode: nil -*-

#|

Copyright 2006, 2007 Greg Pfeil

Distributed under the MIT license (see LICENSE file)
|#

(in-package #:bordeaux-threads)

;;; documentation on the OpenMCL Threads interface can be found at
;;; http://openmcl.clozure.com/Doc/Programming-with-Threads.html

(deftype thread ()
  'ccl:process)

;;; Thread Creation

(defun %make-thread (function name)

  (ccl:process-run-function name function))

(defun current-thread ()

  ccl:*current-process*)

(defun threadp (object)
  (typep object 'ccl:process))

(defun thread-name (thread)

  (ccl:process-name thread))

;;; Resource contention: locks and recursive locks

(defun make-lock (&optional name)

  (ccl:make-lock (or name "Anonymous lock")))

(defun acquire-lock (lock &optional (wait-p t))

  (if wait-p
      (ccl:grab-lock lock)
      (ccl:try-lock lock)))

(defun release-lock (lock)

  (ccl:release-lock lock))

(defmacro with-lock-held ((place) &body body)
  `(ccl:with-lock-grabbed (,place)
     ,@body))

(defun make-recursive-lock (&optional name)

  (ccl:make-lock (or name "Anonymous recursive lock")))

(defun acquire-recursive-lock (lock)

  (ccl:grab-lock lock))

(defun release-recursive-lock (lock)

  (ccl:release-lock lock))

(defmacro with-recursive-lock-held ((place) &body body)
  `(ccl:with-lock-grabbed (,place)
     ,@body))

;;; Resource contention: condition variables

(defun make-condition-variable (&key name)
  (declare (ignore name))

  (ccl:make-semaphore))

(defun condition-wait (condition-variable lock)

  (release-lock lock)

  (unwind-protect

       (ccl:wait-on-semaphore condition-variable)

    (acquire-lock lock t)))

(defun condition-notify (condition-variable)

  (ccl:signal-semaphore condition-variable))

(defun thread-yield ()

  (ccl:process-allow-schedule))

;;; Introspection/debugging

(defun all-threads ()

  (ccl:all-processes))

(defun interrupt-thread (thread function &rest args)

  (declare (dynamic-extent args))

  (apply #'ccl:process-interrupt thread function args))

(defun destroy-thread (thread)
  (signal-error-if-current-thread thread)

  (ccl:process-kill thread))

(defun thread-alive-p (thread)

  (ccl::process-active-p thread))

(defun join-thread (thread)
  (ccl:join-process thread))