From 89ceb86ad415ea92450ebda60359a7ee0ec79eb6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Mon, 3 Jun 2019 16:24:31 +0200
Subject: [PATCH] syscalls: 'with-file-lock' expands to a call to
 'call-with-file-lock'.

* guix/build/syscalls.scm (call-with-file-lock): New procedure.
(with-file-lock): Expand to a call to 'call-with-file-lock'.
---
 guix/build/syscalls.scm | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 04fbebb8a2..3af41f2cf5 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -1083,17 +1083,19 @@ exception if it's already taken."
   (close-port port)
   #t)
 
-(define-syntax-rule (with-file-lock file exp ...)
-  "Wait to acquire a lock on FILE and evaluate EXP in that context."
+(define (call-with-file-lock file thunk)
   (let ((port (lock-file file)))
     (dynamic-wind
       (lambda ()
         #t)
-      (lambda ()
-        exp ...)
+      thunk
       (lambda ()
         (unlock-file port)))))
 
+(define-syntax-rule (with-file-lock file exp ...)
+  "Wait to acquire a lock on FILE and evaluate EXP in that context."
+  (call-with-file-lock file (lambda () exp ...)))
+
 
 ;;;
 ;;; Miscellaneous, aka. 'prctl'.