10/13: utils: Add 'switch-symlinks', moved from (guix ui).

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit 3bb168b0997d2ba2ef15e8eef2890582c8a6df9c
Author: Ludovic Courtès <address@hidden>
Date:   Mon Oct 26 22:17:25 2015 +0100

    utils: Add 'switch-symlinks', moved from (guix ui).
    
    * guix/ui.scm (switch-symlinks): Move to...
    * guix/utils.scm: ... here.  New procedure.
    * guix/scripts/pull.scm: Use it.
---
 guix/scripts/pull.scm |    1 +
 guix/ui.scm           |    8 --------
 guix/utils.scm        |    8 ++++++++
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/guix/scripts/pull.scm b/guix/scripts/pull.scm
index 56ee9ac..a4824e4 100644
--- a/guix/scripts/pull.scm
+++ b/guix/scripts/pull.scm
@@ -18,6 +18,7 @@
 
 (define-module (guix scripts pull)
   #:use-module (guix ui)
+  #:use-module (guix utils)
   #:use-module (guix scripts)
   #:use-module (guix store)
   #:use-module (guix config)
diff --git a/guix/ui.scm b/guix/ui.scm
index c45c50f..b7ed5e7 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -73,7 +73,6 @@
             read/eval
             read/eval-package-expression
             location->string
-            switch-symlinks
             config-directory
             fill-paragraph
             texi->plain-text
@@ -715,13 +714,6 @@ replacement if PORT is not Unicode-capable."
     (($ <location> file line column)
      (format #f "~a:~a:~a" file line column))))
 
-(define (switch-symlinks link target)
-  "Atomically switch LINK, a symbolic link, to point to TARGET.  Works
-both when LINK already exists and when it does not."
-  (let ((pivot (string-append link ".new")))
-    (symlink target pivot)
-    (rename-file pivot link)))
-
 (define (config-directory)
   "Return the name of the configuration directory, after making sure that it
 exists.  Honor the XDG specs,
diff --git a/guix/utils.scm b/guix/utils.scm
index f1317ac..1542e86 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -74,6 +74,7 @@
             arguments-from-environment-variable
             file-extension
             file-sans-extension
+            switch-symlinks
             call-with-temporary-output-file
             call-with-temporary-directory
             with-atomic-file-output
@@ -557,6 +558,13 @@ minor version numbers from version-string."
         (substring file 0 dot)
         file)))
 
+(define (switch-symlinks link target)
+  "Atomically switch LINK, a symbolic link, to point to TARGET.  Works
+both when LINK already exists and when it does not."
+  (let ((pivot (string-append link ".new")))
+    (symlink target pivot)
+    (rename-file pivot link)))
+
 (define* (string-replace-substring str substr replacement
                                    #:optional
                                    (start 0)