0.9.2.43:

[sbcl.git] / src / code / thread.lisp

diff --git a/src/code/thread.lisp b/src/code/thread.lisp
index c5c7104..9671d60 100644 (file)
--- a/src/code/thread.lisp
+++ b/src/code/thread.lisp
@@ -1,31 +1,63 @@
-(in-package :sb!thread)
+;;;; support for threads needed at cross-compile time
 
-#+sb-xc-host
-(defun make-mutex (&key name value) nil)
+;;;; 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.
 
-#+sb-xc-host
-(defmacro with-recursive-lock ((mutex) &body body)
-  `(progn ,@body))
+(in-package "SB!THREAD")
 
-#-sb-xc-host
-(defmacro with-recursive-lock ((mutex) &body body)
-  (let ((cfp (gensym "CFP")))
-    `(let ((,cfp (ash (sb!sys:sap-int (sb!vm::current-fp) ) -2)))
-      (unless (and (mutex-value ,mutex)
-                  (SB!DI::control-stack-pointer-valid-p
-                   (sb!sys:int-sap (ash (mutex-value ,mutex) 2))))
-       (get-mutex ,mutex ,cfp))
-      (unwind-protect
-          (progn ,@body)
-       (when (eql (mutex-value ,mutex) ,cfp) (release-mutex ,mutex))))))
-
-(defun get-foreground ()
-  (when (not (eql (mutex-value *session-lock*)  (CURRENT-THREAD-ID)))
-    (get-mutex *session-lock*))
-  (sb!sys:enable-interrupt :sigint #'sb!unix::sigint-handler)
-  t)
+(sb!xc:defmacro with-mutex ((mutex &key value (wait-p t)) &body body)
+  #!+sb-doc
+  "Acquire MUTEX for the dynamic scope of BODY, setting it to
+NEW-VALUE or some suitable default value if NIL.  If WAIT-P is non-NIL
+and the mutex is in use, sleep until it is available"
+  #!-sb-thread (declare (ignore mutex value wait-p))
+  #!+sb-thread
+  (with-unique-names (got)
+    `(let ((,got (get-mutex ,mutex ,value ,wait-p)))
+      (when ,got
+        (unwind-protect
+             (locally ,@body)
+          (release-mutex ,mutex)))))
+  ;; KLUDGE: this separate expansion for (NOT SB-THREAD) is not
+  ;; strictly necessary; GET-MUTEX and RELEASE-MUTEX are implemented.
+  ;; However, there would be a (possibly slight) performance hit in
+  ;; using them.
+  #!-sb-thread
+  `(locally ,@body))
 
-(defun release-foreground ()
-  (sb!sys:enable-interrupt :sigint :ignore)
-  (release-mutex *session-lock*)
-  t)
+(sb!xc:defmacro with-recursive-lock ((mutex) &body body)
+  #!+sb-doc
+  "Acquires MUTEX for the dynamic scope of BODY. Within that scope
+further recursive lock attempts for the same mutex succeed. However,
+it is an error to mix WITH-MUTEX and WITH-RECURSIVE-LOCK for the same
+mutex."
+  #!-sb-thread (declare (ignore mutex))
+  #!+sb-thread
+  (with-unique-names (cfp inner-lock)
+    `(let ((,cfp (sb!kernel:current-fp))
+           (,inner-lock
+            (and (mutex-value ,mutex)
+                 (sb!vm:control-stack-pointer-valid-p
+                  (sb!sys:int-sap
+                   (sb!kernel:get-lisp-obj-address (mutex-value ,mutex)))))))
+      (unless ,inner-lock
+        ;; this punning with MAKE-LISP-OBJ depends for its safety on
+        ;; the frame pointer being a lispobj-aligned integer.  While
+        ;; it is, then MAKE-LISP-OBJ will always return a FIXNUM, so
+        ;; we're safe to do that.  Should this ever change, this
+        ;; MAKE-LISP-OBJ could return something that looks like a
+        ;; pointer, but pointing into neverneverland, which will
+        ;; confuse GC completely.  -- CSR, 2003-06-03
+        (get-mutex ,mutex (sb!kernel:make-lisp-obj (sb!sys:sap-int ,cfp))))
+      (unwind-protect
+           (locally ,@body)
+        (unless ,inner-lock
+          (release-mutex ,mutex)))))
+  #!-sb-thread
+  `(locally ,@body))