07/15: utils: Add call-with-temporary-directory.

[David Thompson]

davexunit pushed a commit to branch wip-container
in repository guix.

commit a3eb988d0d4443993f344d3cf64542f7ea6a34d7
Author: David Thompson <address@hidden>
Date:   Wed Jun 24 21:16:11 2015 -0400

    utils: Add call-with-temporary-directory.
    
    * guix/utils.scm (call-with-temporary-directory): New procedure.
---
 guix/utils.scm |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/guix/utils.scm b/guix/utils.scm
index a2ade2b..44913c6 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -30,7 +30,7 @@
   #:use-module (rnrs bytevectors)
   #:use-module ((rnrs io ports) #:select (put-bytevector))
   #:use-module ((guix build utils) #:select (dump-port))
-  #:use-module ((guix build syscalls) #:select (errno))
+  #:use-module ((guix build syscalls) #:select (errno mkdtemp!))
   #:use-module (ice-9 vlist)
   #:use-module (ice-9 format)
   #:autoload   (ice-9 popen)  (open-pipe*)
@@ -77,6 +77,7 @@
             file-extension
             file-sans-extension
             call-with-temporary-output-file
+            call-with-temporary-directory
             with-atomic-file-output
             fold2
             fold-tree
@@ -652,6 +653,19 @@ call."
         (false-if-exception (close out))
         (false-if-exception (delete-file template))))))
 
+(define (call-with-temporary-directory proc)
+  "Call PROC with a name of a temporary directory; close the directory and
+delete it when leaving the dynamic extent of this call."
+  (let* ((directory (or (getenv "TMPDIR") "/tmp"))
+         (template  (string-append directory "/guix-directory.XXXXXX"))
+         (tmp-dir   (mkdtemp! template)))
+    (dynamic-wind
+      (const #t)
+      (lambda ()
+        (proc tmp-dir))
+      (lambda ()
+        (false-if-exception (rmdir tmp-dir))))))
+
 (define (with-atomic-file-output file proc)
   "Call PROC with an output port for the file that is going to replace FILE.
 Upon success, FILE is atomically replaced by what has been written to the