0.9.8.38:

[sbcl.git] / src / code / host-c-call.lisp

diff --git a/src/code/host-c-call.lisp b/src/code/host-c-call.lisp
index b7730f1..8050231 100644 (file)
--- a/src/code/host-c-call.lisp
+++ b/src/code/host-c-call.lisp
@@ -14,9 +14,8 @@
 (define-alien-type-class (c-string :include pointer :include-args (to)))
 
 (define-alien-type-translator c-string ()
-  (make-alien-c-string-type :to
-                           (parse-alien-type 'char
-                                             (sb!kernel::make-null-lexenv))))
+  (make-alien-c-string-type
+   :to (parse-alien-type 'char (sb!kernel:make-null-lexenv))))
 
 (define-alien-type-method (c-string :unparse) (type)
   (declare (ignore type))
@@ -24,7 +23,7 @@
 
 (define-alien-type-method (c-string :lisp-rep) (type)
   (declare (ignore type))
-  '(or simple-base-string null (alien (* char))))
+  '(or simple-string null (alien (* char))))
 
 (define-alien-type-method (c-string :naturalize-gen) (type alien)
   (declare (ignore type))
@@ -37,6 +36,63 @@
   `(etypecase ,value
      (null (int-sap 0))
      ((alien (* char)) (alien-sap ,value))
-     (simple-base-string (vector-sap ,value))))
+     ;; FIXME: GC safety alert! These SAPs are not safe, since the
+     ;; Lisp string can move. This is not hard to arrange, for example
+     ;; the following will fail very quickly on a SB-UNICODE build:
+     ;;
+     ;;   (setf (bytes-consed-between-gcs) 4096)
+     ;;   (define-alien-routine "strcmp" int (s1 c-string) (s2 c-string))
+     ;;
+     ;;   (loop
+     ;;     (let ((string "hello, world"))
+     ;;       (assert (zerop (strcmp string string)))))
+     ;;
+     ;; (This will appear to work on post-0.9.8.19 GENCGC, since
+     ;;  the GC no longer zeroes memory immediately after releasing
+     ;;  it after a minor GC. Either enabling the READ_PROTECT_FREE_PAGES
+     ;;  #define in gencgc.c or modifying the example so that a major
+     ;;  GC will occasionally be triggered would unmask the bug).
+     ;;
+     ;; The SIMPLE-BASE-STRING case will generally be very hard to
+     ;; trigger on GENCGC (even when threaded) thanks to GC
+     ;; conservativeness. It's mostly a problem on cheneygc.
+     ;; -- JES, 2006-01-13
+     (simple-base-string (vector-sap ,value))
+     ;; This case, on the other hand, will cause trouble on GENCGC, since
+     ;; we're taking the SAP of a immediately discarded temporary -> the
+     ;; conservativeness doesn't protect us.
+     ;; -- JES, 2006-01-13
+     (simple-string (vector-sap (coerce ,value 'simple-base-string)))))
+
+(/show0 "host-c-call.lisp 42")
+
+(define-alien-type-class (utf8-string :include pointer :include-args (to)))
+
+(define-alien-type-translator utf8-string ()
+  (make-alien-utf8-string-type
+   :to (parse-alien-type 'char (sb!kernel:make-null-lexenv))))
+
+(define-alien-type-method (utf8-string :unparse) (type)
+  (declare (ignore type))
+  'utf8-string)
+
+(define-alien-type-method (utf8-string :lisp-rep) (type)
+  (declare (ignore type))
+  '(or simple-string null (alien (* char))))
+
+(define-alien-type-method (utf8-string :naturalize-gen) (type alien)
+  (declare (ignore type))
+  `(if (zerop (sap-int ,alien))
+       nil
+       (%naturalize-utf8-string ,alien)))
+
+(define-alien-type-method (utf8-string :deport-gen) (type value)
+  (declare (ignore type))
+  `(etypecase ,value
+     (null (int-sap 0))
+     ((alien (* char)) (alien-sap ,value))
+     ;; See the C-STRING :DEPORT-GEN comments for GC safety issues.
+     (simple-base-string (vector-sap ,value))
+     (simple-string (vector-sap (%deport-utf8-string ,value)))))
 
 (/show0 "host-c-call.lisp end of file")