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authorLudovic Courtès <ludo@gnu.org>2016-04-17 00:05:06 +0200
committerLudovic Courtès <ludo@gnu.org>2016-04-17 01:23:52 +0200
commit2447335625fb0b8fcb9aae0852d86eb6310188ce (patch)
tree730e1e2d7958b86d1fd353171b511a01f7862d61
parente9dffec1265233c3b37ef61538b51f121a420ffa (diff)
downloadguix-2447335625fb0b8fcb9aae0852d86eb6310188ce.tar
guix-2447335625fb0b8fcb9aae0852d86eb6310188ce.tar.gz
file-systems: Separate ENOENT catching from ext2 superblock reads.
* gnu/build/file-systems.scm (ENOENT-safe): New procedure. (read-ext2-superblock*): Rewrite in terms of it.
-rw-r--r--gnu/build/file-systems.scm36
1 files changed, 20 insertions, 16 deletions
diff --git a/gnu/build/file-systems.scm b/gnu/build/file-systems.scm
index 58ccf599d6..9af4f5ad1b 100644
--- a/gnu/build/file-systems.scm
+++ b/gnu/build/file-systems.scm
@@ -167,22 +167,26 @@ if DEVICE does not contain an ext2 file system."
(loop (cons name parts))
(loop parts))))))))))
-(define (read-ext2-superblock* device)
- "Like 'read-ext2-superblock', but return #f when DEVICE does not exist
-instead of throwing an exception."
- (catch 'system-error
- (lambda ()
- (read-ext2-superblock device))
- (lambda args
- ;; When running on the hand-made /dev,
- ;; 'disk-partitions' could return partitions for which
- ;; we have no /dev node. Handle that gracefully.
- (if (= ENOENT (system-error-errno args))
- (begin
- (format (current-error-port)
- "warning: device '~a' not found~%" device)
- #f)
- (apply throw args)))))
+(define (ENOENT-safe proc)
+ "Wrap the one-argument PROC such that ENOENT errors are caught and lead to a
+warning and #f as the result."
+ (lambda (device)
+ (catch 'system-error
+ (lambda ()
+ (proc device))
+ (lambda args
+ ;; When running on the hand-made /dev,
+ ;; 'disk-partitions' could return partitions for which
+ ;; we have no /dev node. Handle that gracefully.
+ (if (= ENOENT (system-error-errno args))
+ (begin
+ (format (current-error-port)
+ "warning: device '~a' not found~%" device)
+ #f)
+ (apply throw args))))))
+
+(define read-ext2-superblock*
+ (ENOENT-safe read-ext2-superblock))
(define (partition-predicate field =)
"Return a predicate that returns true if the FIELD of an ext2 superblock is