-(in-package "SB!THREAD")
+;;;; support for threads in the target machine
-(sb!alien::define-alien-routine ("create_thread" %create-thread)
- sb!alien:unsigned-long
- (lisp-fun-address sb!alien:unsigned-long))
+;;;; This software is part of the SBCL system. See the README file for
+;;;; more information.
+;;;;
+;;;; This software is derived from the CMU CL system, which was
+;;;; written at Carnegie Mellon University and released into the
+;;;; public domain. The software is in the public domain and is
+;;;; provided with absolutely no warranty. See the COPYING and CREDITS
+;;;; files for more information.
-(defun make-thread (function)
- (let ((real-function (coerce function 'function)))
- (%create-thread
- (sb!kernel:get-lisp-obj-address
- (lambda ()
- ;; in time we'll move some of the binding presently done in C
- ;; here too
- (let ((sb!kernel::*restart-clusters* nil)
- (sb!impl::*descriptor-handlers* nil); serve-event
- (sb!impl::*available-buffers* nil)) ;for fd-stream
- ;; can't use handling-end-of-the-world, because that flushes
- ;; output streams, and we don't necessarily have any (or we
- ;; could be sharing them)
- (sb!sys:enable-interrupt :sigint :ignore)
- (sb!unix:unix-exit
- (catch 'sb!impl::%end-of-the-world
- (with-simple-restart
- (destroy-thread
- (format nil "~~@<Destroy this thread (~A)~~@:>"
- (current-thread-id)))
- (funcall real-function))
- 0))))))))
+(in-package "SB!THREAD")
-(defun destroy-thread (thread-id)
- (sb!unix:unix-kill thread-id :sigterm)
- ;; may have been stopped for some reason, so now wake it up to
- ;; deliver the TERM
- (sb!unix:unix-kill thread-id :sigcont))
-
-;; Conventional wisdom says that it's a bad idea to use these unless
-;; you really need to. Use a lock or a waitqueue instead
-(defun suspend-thread (thread-id)
- (sb!unix:unix-kill thread-id :sigstop))
-(defun resume-thread (thread-id)
- (sb!unix:unix-kill thread-id :sigcont))
+;;; FIXME it would be good to define what a thread id is or isn't (our
+;;; current assumption is that it's a fixnum). It so happens that on
+;;; Linux it's a pid, but it might not be on posix thread implementations
-(defun current-thread-id ()
- (sb!sys:sap-int
- (sb!vm::current-thread-offset-sap sb!vm::thread-pid-slot)))
+(define-alien-routine ("create_thread" %create-thread)
+ unsigned-long
+ (lisp-fun-address unsigned-long))
-;;;; iterate over the in-memory threads
+(define-alien-routine reap-dead-threads void)
-(defun mapcar-threads (function)
- "Call FUNCTION once for each known thread, giving it the thread structure as argument"
- (let ((function (coerce function 'function)))
- (loop for thread = (alien-sap (extern-alien "all_threads" (* t)))
- then (sb!sys:sap-ref-sap thread (* 4 sb!vm::thread-next-slot))
- until (sb!sys:sap= thread (sb!sys:int-sap 0))
- collect (funcall function thread))))
+(defvar *session* nil)
;;;; queues, locks
;; spinlocks use 0 as "free" value: higher-level locks use NIL
+(declaim (inline get-spinlock release-spinlock))
+
(defun get-spinlock (lock offset new-value)
(declare (optimize (speed 3) (safety 0)))
(loop until
(eql (sb!vm::%instance-set-conditional lock offset 0 new-value) 0)))
+;; this should do nothing if we didn't own the lock, so safe to use in
+;; unwind-protect cleanups when lock acquisition failed for some reason
+(defun release-spinlock (lock offset our-value)
+ (declare (optimize (speed 3) (safety 0)))
+ (sb!vm::%instance-set-conditional lock offset our-value 0))
+
(defmacro with-spinlock ((queue) &body body)
- (let ((pid (gensym "PID")))
- `(unwind-protect
- (let ((,pid (current-thread-id)))
- (get-spinlock ,queue 2 ,pid)
- ,@body)
- (setf (waitqueue-lock ,queue) 0))))
+ (with-unique-names (pid)
+ `(let ((,pid (current-thread-id)))
+ (unwind-protect
+ (progn
+ (get-spinlock ,queue 2 ,pid)
+ ,@body)
+ (release-spinlock ,queue 2 ,pid)))))
+
;;;; the higher-level locking operations are based on waitqueues
+(declaim (inline waitqueue-data-address mutex-value-address))
+
(defstruct waitqueue
- (name nil :type (or null simple-base-string))
+ (name nil :type (or null simple-string))
(lock 0)
(data nil))
+;;; The bare 4 here and 5 below are offsets of the slots in the struct.
+;;; There ought to be some better way to get these numbers
+(defun waitqueue-data-address (lock)
+ (declare (optimize (speed 3)))
+ (sb!ext:truly-the
+ (unsigned-byte 32)
+ (+ (sb!kernel:get-lisp-obj-address lock)
+ (- (* 4 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag))))
+
(defstruct (mutex (:include waitqueue))
(value nil))
-(sb!alien:define-alien-routine "block_sigcont" void)
-(sb!alien:define-alien-routine "unblock_sigcont_and_sleep" void)
-
-(defun wait-on-queue (queue &optional lock)
- (let ((pid (current-thread-id)))
- ;; FIXME what should happen if we get interrupted when we've blocked
- ;; the sigcont? For that matter, can we get interrupted?
- (block-sigcont)
- (when lock (release-mutex lock))
- (get-spinlock queue 2 pid)
- (pushnew pid (waitqueue-data queue))
- (setf (waitqueue-lock queue) 0)
- (unblock-sigcont-and-sleep)))
-
-(defun dequeue (queue)
- (let ((pid (current-thread-id)))
- (get-spinlock queue 2 pid)
- (setf (waitqueue-data queue)
- (delete pid (waitqueue-data queue)))
- (setf (waitqueue-lock queue) 0)))
-
-(defun signal-queue-head (queue)
- (let ((pid (current-thread-id)))
- (get-spinlock queue 2 pid)
- (let ((h (car (waitqueue-data queue))))
- (setf (waitqueue-lock queue) 0)
- (when h
- (sb!unix:unix-kill h :sigcont)))))
+(defun mutex-value-address (lock)
+ (declare (optimize (speed 3)))
+ (sb!ext:truly-the
+ (unsigned-byte 32)
+ (+ (sb!kernel:get-lisp-obj-address lock)
+ (- (* 5 sb!vm:n-word-bytes) sb!vm:instance-pointer-lowtag))))
+
+(declaim (inline futex-wait futex-wake))
+(sb!alien:define-alien-routine
+ "futex_wait" int (word unsigned-long) (old-value unsigned-long))
+(sb!alien:define-alien-routine
+ "futex_wake" int (word unsigned-long) (n unsigned-long))
+
;;;; mutex
(defun get-mutex (lock &optional new-value (wait-p t))
- (declare (type mutex lock))
- (let ((pid (current-thread-id)))
+ "Acquire LOCK, setting it to NEW-VALUE or some suitable default value
+if NIL. If WAIT-P is non-NIL and the lock is in use, sleep until it
+is available"
+ (declare (type mutex lock) (optimize (speed 3)))
+ (let ((pid (current-thread-id))
+ old)
(unless new-value (setf new-value pid))
- (assert (not (eql new-value (mutex-value lock))))
+ (when (eql new-value (mutex-value lock))
+ (warn "recursive lock attempt ~S~%" lock))
(loop
(unless
- ;; args are object slot-num old-value new-value
- (sb!vm::%instance-set-conditional lock 4 nil new-value)
- (dequeue lock)
+ (setf old (sb!vm::%instance-set-conditional lock 4 nil new-value))
(return t))
(unless wait-p (return nil))
- (wait-on-queue lock nil))))
+ (futex-wait (mutex-value-address lock)
+ (sb!kernel:get-lisp-obj-address old)))))
-(defun release-mutex (lock &optional (new-value nil))
+(defun release-mutex (lock)
(declare (type mutex lock))
- (let ((old-value (mutex-value lock))
- (t1 nil))
- (loop
- (unless
- ;; args are object slot-num old-value new-value
- (eql old-value
- (setf t1
- (sb!vm::%instance-set-conditional lock 4 old-value new-value)))
- (signal-queue-head lock)
- (return t))
- (setf old-value t1))))
-
-(defmacro with-mutex ((mutex &key value (wait-p t)) &body body)
- (let ((block (gensym "NIL")))
- `(unwind-protect
- (block ,block
- (unless (get-mutex ,mutex ,value ,wait-p) (return-from ,block nil))
- ,@body)
- (release-mutex ,mutex))))
-
+ (setf (mutex-value lock) nil)
+ (futex-wake (mutex-value-address lock) 1))
;;;; condition variables
"Atomically release LOCK and enqueue ourselves on QUEUE. Another
thread may subsequently notify us using CONDITION-NOTIFY, at which
time we reacquire LOCK and return to the caller."
- (unwind-protect
- (wait-on-queue queue lock)
- ;; If we are interrupted while waiting, we should do these things
- ;; before returning. Ideally, in the case of an unhandled signal,
- ;; we should do them before entering the debugger, but this is
- ;; better than nothing.
- (dequeue queue)
- (get-mutex lock)))
+ (assert lock)
+ (let ((value (mutex-value lock)))
+ (unwind-protect
+ (let ((me (current-thread-id)))
+ ;; XXX we should do something to ensure that the result of this setf
+ ;; is visible to all CPUs
+ (setf (waitqueue-data queue) me)
+ (release-mutex lock)
+ ;; Now we go to sleep using futex-wait. If anyone else
+ ;; manages to grab LOCK and call CONDITION-NOTIFY during
+ ;; this comment, it will change queue->data, and so
+ ;; futex-wait returns immediately instead of sleeping.
+ ;; Ergo, no lost wakeup
+ (futex-wait (waitqueue-data-address queue)
+ (sb!kernel:get-lisp-obj-address me)))
+ ;; If we are interrupted while waiting, we should do these things
+ ;; before returning. Ideally, in the case of an unhandled signal,
+ ;; we should do them before entering the debugger, but this is
+ ;; better than nothing.
+ (get-mutex lock value))))
+
(defun condition-notify (queue)
"Notify one of the processes waiting on QUEUE"
- (signal-queue-head queue))
+ (let ((me (current-thread-id)))
+ ;; no problem if >1 thread notifies during the comment in
+ ;; condition-wait: as long as the value in queue-data isn't the
+ ;; waiting thread's id, it matters not what it is
+ ;; XXX we should do something to ensure that the result of this setf
+ ;; is visible to all CPUs
+ (setf (waitqueue-data queue) me)
+ (futex-wake (waitqueue-data-address queue) 1)))
+
+(defun condition-broadcast (queue)
+ (let ((me (current-thread-id)))
+ (setf (waitqueue-data queue) me)
+ (futex-wake (waitqueue-data-address queue) (ash 1 30))))
+(defun make-thread (function)
+ (let* ((real-function (coerce function 'function))
+ (tid
+ (%create-thread
+ (sb!kernel:get-lisp-obj-address
+ (lambda ()
+ ;; in time we'll move some of the binding presently done in C
+ ;; here too
+ (let ((sb!kernel::*restart-clusters* nil)
+ (sb!kernel::*handler-clusters* nil)
+ (sb!kernel::*condition-restarts* nil)
+ (sb!impl::*descriptor-handlers* nil) ; serve-event
+ (sb!impl::*available-buffers* nil)) ;for fd-stream
+ ;; can't use handling-end-of-the-world, because that flushes
+ ;; output streams, and we don't necessarily have any (or we
+ ;; could be sharing them)
+ (catch 'sb!impl::%end-of-the-world
+ (with-simple-restart
+ (terminate-thread
+ (format nil "~~@<Terminate this thread (~A)~~@:>"
+ (current-thread-id)))
+ ;; now that most things have a chance to work
+ ;; properly without messing up other threads, it's
+ ;; time to enable signals
+ (sb!unix::reset-signal-mask)
+ (funcall real-function))
+ 0))
+ (values))))))
+ (when (zerop tid) (error "Can't create a new thread"))
+ (with-mutex ((session-lock *session*))
+ (pushnew tid (session-threads *session*)))
+ tid))
-;;;; multiple independent listeners
+(defun destroy-thread (thread-id)
+ "Deprecated. Soon to be removed or reimplemented using pthread_cancel."
+ (terminate-thread thread-id))
+
+;;; a moderate degree of care is expected for use of interrupt-thread,
+;;; due to its nature: if you interrupt a thread that was holding
+;;; important locks then do something that turns out to need those
+;;; locks, you probably won't like the effect. Used with thought
+;;; though, it's a good deal gentler than the last-resort functions above
+
+(define-condition interrupt-thread-error (error)
+ ((thread :reader interrupt-thread-error-thread :initarg :thread)
+ (errno :reader interrupt-thread-error-errno :initarg :errno))
+ (:report (lambda (c s)
+ (format s "interrupt thread ~A failed (~A: ~A)"
+ (interrupt-thread-error-thread c)
+ (interrupt-thread-error-errno c)
+ (strerror (interrupt-thread-error-errno c))))))
+
+(defun interrupt-thread (thread function)
+ "Interrupt THREAD and make it run FUNCTION."
+ (let ((function (coerce function 'function)))
+ (multiple-value-bind (res err)
+ (sb!unix::syscall ("interrupt_thread"
+ sb!alien:unsigned-long sb!alien:unsigned-long)
+ thread
+ thread
+ (sb!kernel:get-lisp-obj-address function))
+ (unless res
+ (error 'interrupt-thread-error :thread thread :errno err)))))
+
+
+(defun terminate-thread (thread-id)
+ "Terminate the thread identified by THREAD-ID, by causing it to run
+SB-EXT:QUIT - the usual cleanup forms will be evaluated"
+ (interrupt-thread thread-id 'sb!ext:quit))
+
+(declaim (inline current-thread-id))
+(defun current-thread-id ()
+ (sb!sys:sap-int
+ (sb!vm::current-thread-offset-sap sb!vm::thread-os-thread-slot)))
-(defvar *session-lock* nil)
+;;;; iterate over the in-memory threads
+
+(defun mapcar-threads (function)
+ "Call FUNCTION once for each known thread, giving it the thread structure as argument"
+ (let ((function (coerce function 'function)))
+ (loop for thread = (alien-sap (extern-alien "all_threads" (* t)))
+ then (sb!sys:sap-ref-sap thread (* sb!vm:n-word-bytes
+ sb!vm::thread-next-slot))
+ until (sb!sys:sap= thread (sb!sys:int-sap 0))
+ collect (funcall function thread))))
+
+(defun thread-sap-from-id (id)
+ (let ((thread (alien-sap (extern-alien "all_threads" (* t)))))
+ (loop
+ (when (sb!sys:sap= thread (sb!sys:int-sap 0)) (return nil))
+ ;; FIXME: 32/64 bit
+ (let ((pid (sb!sys:sap-ref-32 thread (* sb!vm:n-word-bytes
+ sb!vm::thread-os-thread-slot))))
+ (when (= pid id) (return thread))
+ (setf thread (sb!sys:sap-ref-sap thread (* sb!vm:n-word-bytes
+ sb!vm::thread-next-slot)))))))
+
+;;; internal use only. If you think you need to use this, either you
+;;; are an SBCL developer, are doing something that you should discuss
+;;; with an SBCL developer first, or are doing something that you
+;;; should probably discuss with a professional psychiatrist first
+(defun symbol-value-in-thread (symbol thread-id)
+ (let ((thread (thread-sap-from-id thread-id)))
+ (when thread
+ (let* ((index (sb!vm::symbol-tls-index symbol))
+ (tl-val (sb!sys:sap-ref-word thread
+ (* sb!vm:n-word-bytes index))))
+ (if (eql tl-val sb!vm::unbound-marker-widetag)
+ (sb!vm::symbol-global-value symbol)
+ (sb!kernel:make-lisp-obj tl-val))))))
+
+;;;; job control, independent listeners
+
+(defstruct session
+ (lock (make-mutex :name "session lock"))
+ (threads nil)
+ (interactive-threads nil)
+ (interactive-threads-queue (make-waitqueue)))
+
+(defun new-session ()
+ (let ((tid (current-thread-id)))
+ (make-session :threads (list tid)
+ :interactive-threads (list tid))))
+
+(defun init-job-control ()
+ (setf *session* (new-session)))
+
+(defun %delete-thread-from-session (tid session)
+ (with-mutex ((session-lock session))
+ (setf (session-threads session)
+ (delete tid (session-threads session))
+ (session-interactive-threads session)
+ (delete tid (session-interactive-threads session)))))
+
+(defun call-with-new-session (fn)
+ (%delete-thread-from-session (current-thread-id) *session*)
+ (let ((*session* (new-session))) (funcall fn)))
+
+(defmacro with-new-session (args &body forms)
+ (declare (ignore args)) ;for extensibility
+ (sb!int:with-unique-names (fb-name)
+ `(labels ((,fb-name () ,@forms))
+ (call-with-new-session (function ,fb-name)))))
+
+;;; Remove thread id TID from its session, if it has one. This is
+;;; called from C mark_thread_dead().
+(defun handle-thread-exit (tid)
+ (when *session*
+ (%delete-thread-from-session tid *session*)))
+
+(defun terminate-session ()
+ "Kill all threads in session except for this one. Does nothing if current
+thread is not the foreground thread"
+ (reap-dead-threads)
+ ;; FIXME: threads created in other threads may escape termination
+ (let* ((tid (current-thread-id))
+ (to-kill
+ (with-mutex ((session-lock *session*))
+ (and (eql tid (car (session-interactive-threads *session*)))
+ (session-threads *session*)))))
+ ;; do the kill after dropping the mutex; unwind forms in dying
+ ;; threads may want to do session things
+ (dolist (p to-kill)
+ (unless (eql p tid)
+ ;; terminate the thread but don't be surprised if it has
+ ;; exited in the meantime
+ (handler-case (terminate-thread p)
+ (interrupt-thread-error ()))))))
+
+;;; called from top of invoke-debugger
+(defun debugger-wait-until-foreground-thread (stream)
+ "Returns T if thread had been running in background, NIL if it was
+interactive."
+ (declare (ignore stream))
+ (prog1
+ (with-mutex ((session-lock *session*))
+ (not (member (current-thread-id)
+ (session-interactive-threads *session*))))
+ (get-foreground)))
+
+
+(defun get-foreground ()
+ (let ((was-foreground t))
+ (loop
+ (with-mutex ((session-lock *session*))
+ (let ((tid (current-thread-id))
+ (int-t (session-interactive-threads *session*)))
+ (when (eql (car int-t) tid)
+ (unless was-foreground
+ (format *query-io* "Resuming thread ~A~%" tid))
+ (return-from get-foreground t))
+ (setf was-foreground nil)
+ (unless (member tid int-t)
+ (setf (cdr (last int-t))
+ (list tid)))
+ (condition-wait
+ (session-interactive-threads-queue *session*)
+ (session-lock *session*)))))))
+
+(defun release-foreground (&optional next)
+ "Background this thread. If NEXT is supplied, arrange for it to have the foreground next"
+ (with-mutex ((session-lock *session*))
+ (let ((tid (current-thread-id)))
+ (setf (session-interactive-threads *session*)
+ (delete tid (session-interactive-threads *session*)))
+ (when next
+ (setf (session-interactive-threads *session*)
+ (list* next
+ (delete next (session-interactive-threads *session*)))))
+ (condition-broadcast (session-interactive-threads-queue *session*)))))
+
+(defun foreground-thread ()
+ (car (session-interactive-threads *session*)))
(defun make-listener-thread (tty-name)
(assert (probe-file tty-name))
- ;; FIXME probably still need to do some tty stuff to get signals
- ;; delivered correctly.
- ;; FIXME
(let* ((in (sb!unix:unix-open (namestring tty-name) sb!unix:o_rdwr #o666))
(out (sb!unix:unix-dup in))
(err (sb!unix:unix-dup in)))
(labels ((thread-repl ()
(sb!unix::unix-setsid)
- (let* ((*session-lock*
- (make-mutex :name (format nil "lock for ~A" tty-name)))
- (sb!impl::*stdin*
- (sb!sys:make-fd-stream in :input t :buffering :line))
+ (let* ((sb!impl::*stdin*
+ (sb!sys:make-fd-stream in :input t :buffering :line :dual-channel-p t))
(sb!impl::*stdout*
- (sb!sys:make-fd-stream out :output t :buffering :line))
+ (sb!sys:make-fd-stream out :output t :buffering :line :dual-channel-p t))
(sb!impl::*stderr*
- (sb!sys:make-fd-stream err :output t :buffering :line))
+ (sb!sys:make-fd-stream err :output t :buffering :line :dual-channel-p t))
(sb!impl::*tty*
- (sb!sys:make-fd-stream err :input t :output t :buffering :line))
+ (sb!sys:make-fd-stream err :input t :output t :buffering :line :dual-channel-p t))
(sb!impl::*descriptor-handlers* nil))
- (get-mutex *session-lock*)
- (sb!sys:enable-interrupt :sigint #'sb!unix::sigint-handler)
- (unwind-protect
- (sb!impl::toplevel-repl nil)
- (sb!int:flush-standard-output-streams)))))
+ (with-new-session ()
+ (unwind-protect
+ (sb!impl::toplevel-repl nil)
+ (sb!int:flush-standard-output-streams))))))
(make-thread #'thread-repl))))
-
-;;;; job control
-
-(defvar *background-threads-wait-for-debugger* t)
-;;; may be T, NIL, or a function called with a stream and thread id
-;;; as its two arguments, returning NIl or T
-
-;;; called from top of invoke-debugger
-(defun debugger-wait-until-foreground-thread (stream)
- "Returns T if thread had been running in background, NIL if it was
-already the foreground thread, or transfers control to the first applicable
-restart if *BACKGROUND-THREADS-WAIT-FOR-DEBUGGER* says to do that instead"
- (let* ((wait-p *background-threads-wait-for-debugger*)
- (*background-threads-wait-for-debugger* nil)
- (lock *session-lock*))
- (when (not (eql (mutex-value lock) (CURRENT-THREAD-ID)))
- (when (functionp wait-p)
- (setf wait-p
- (funcall wait-p stream (CURRENT-THREAD-ID))))
- (cond (wait-p (get-foreground))
- (t (invoke-restart (car (compute-restarts))))))))
-
-;;; install this with (setf SB!INT:*REPL-PROMPT-FUN* #'thread-prompt-fun)
-;;; One day it will be default
-(defun thread-repl-prompt-fun (out-stream)
- (let ((lock *session-lock*))
- (get-foreground)
- (let ((stopped-threads (waitqueue-data lock)))
- (when stopped-threads
- (format out-stream "~{~&Thread ~A suspended~}~%" stopped-threads))
- (sb!impl::repl-prompt-fun out-stream))))
-
-(defun resume-stopped-thread (id)
- (let ((pid (current-thread-id))
- (lock *session-lock*))
- (with-spinlock (lock)
- (setf (waitqueue-data lock)
- (cons id (delete id (waitqueue-data lock)))))
- (release-foreground)))
-
-(defstruct rwlock
- (name nil :type (or null simple-base-string))
- (value 0 :type fixnum)
- (max-readers nil :type (or fixnum null))
- (max-writers 1 :type fixnum))
-#+nil
-(macrolet
- ((make-rwlocking-function (lock-fn unlock-fn increment limit test)
- (let ((do-update '(when (eql old-value
- (sb!vm::%instance-set-conditional
- lock 2 old-value new-value))
- (return (values t old-value))))
- (vars `((timeout (and timeout (+ (get-internal-real-time) timeout)))
- old-value
- new-value
- (limit ,limit))))
- (labels ((do-setfs (v) `(setf old-value (rwlock-value lock)
- new-value (,v old-value ,increment))))
- `(progn
- (defun ,lock-fn (lock timeout)
- (declare (type rwlock lock))
- (let ,vars
- (loop
- ,(do-setfs '+)
- (when ,test
- ,do-update)
- (when (sleep-a-bit timeout) (return nil)) ;expired
- )))
- ;; unlock doesn't need timeout or test-in-range
- (defun ,unlock-fn (lock)
- (declare (type rwlock lock))
- (declare (ignorable limit))
- (let ,(cdr vars)
- (loop
- ,(do-setfs '-)
- ,do-update))))))))
-
- (make-rwlocking-function %lock-for-reading %unlock-for-reading 1
- (rwlock-max-readers lock)
- (and (>= old-value 0)
- (or (null limit) (<= new-value limit))))
- (make-rwlocking-function %lock-for-writing %unlock-for-writing -1
- (- (rwlock-max-writers lock))
- (and (<= old-value 0)
- (>= new-value limit))))
-#+nil
-(defun get-rwlock (lock direction &optional timeout)
- (ecase direction
- (:read (%lock-for-reading lock timeout))
- (:write (%lock-for-writing lock timeout))))
-#+nil
-(defun free-rwlock (lock direction)
- (ecase direction
- (:read (%unlock-for-reading lock))
- (:write (%unlock-for-writing lock))))
-
-;;;; beyond this point all is commented.
-
-;;; Lock-Wait-With-Timeout -- Internal
-;;;
-;;; Wait with a timeout for the lock to be free and acquire it for the
-;;; *current-process*.
-;;;
-#+nil
-(defun lock-wait-with-timeout (lock whostate timeout)
- (declare (type lock lock))
- (process-wait-with-timeout
- whostate timeout
- #'(lambda ()
- (declare (optimize (speed 3)))
- #-i486
- (unless (lock-process lock)
- (setf (lock-process lock) *current-process*))
- #+i486
- (null (kernel:%instance-set-conditional
- lock 2 nil *current-process*)))))
-
-;;; With-Lock-Held -- Public
-;;;
-#+nil
-(defmacro with-lock-held ((lock &optional (whostate "Lock Wait")
- &key (wait t) timeout)
- &body body)
- "Execute the body with the lock held. If the lock is held by another
- process then the current process waits until the lock is released or
- an optional timeout is reached. The optional wait timeout is a time in
- seconds acceptable to process-wait-with-timeout. The results of the
- body are return upon success and NIL is return if the timeout is
- reached. When the wait key is NIL and the lock is held by another
- process then NIL is return immediately without processing the body."
- (let ((have-lock (gensym)))
- `(let ((,have-lock (eq (lock-process ,lock) *current-process*)))
- (unwind-protect
- ,(cond ((and timeout wait)
- `(progn
- (when (and (error-check-lock-p ,lock) ,have-lock)
- (error "Dead lock"))
- (when (or ,have-lock
- #+i486 (null (kernel:%instance-set-conditional
- ,lock 2 nil *current-process*))
- #-i486 (seize-lock ,lock)
- (if ,timeout
- (lock-wait-with-timeout
- ,lock ,whostate ,timeout)
- (lock-wait ,lock ,whostate)))
- ,@body)))
- (wait
- `(progn
- (when (and (error-check-lock-p ,lock) ,have-lock)
- (error "Dead lock"))
- (unless (or ,have-lock
- #+i486 (null (kernel:%instance-set-conditional
- ,lock 2 nil *current-process*))
- #-i486 (seize-lock ,lock))
- (lock-wait ,lock ,whostate))
- ,@body))
- (t
- `(when (or (and (recursive-lock-p ,lock) ,have-lock)
- #+i486 (null (kernel:%instance-set-conditional
- ,lock 2 nil *current-process*))
- #-i486 (seize-lock ,lock))
- ,@body)))
- (unless ,have-lock
- #+i486 (kernel:%instance-set-conditional
- ,lock 2 *current-process* nil)
- #-i486 (when (eq (lock-process ,lock) *current-process*)
- (setf (lock-process ,lock) nil)))))))
-
-
-
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