04/07: publish: Remove 'regexp-exec' call from the hot path.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit 33463986ba5093c7513c9dc7702a66929f504aa5
Author: Ludovic Courtès <address@hidden>
Date:   Fri Jul 21 14:48:52 2017 +0200

    publish: Remove 'regexp-exec' call from the hot path.
    
    * guix/scripts/publish.scm (extract-narinfo-hash): Rewrite without
    resorting to regexps.
---
 guix/scripts/publish.scm | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/guix/scripts/publish.scm b/guix/scripts/publish.scm
index a7e3e6d..cb1abc3 100644
--- a/guix/scripts/publish.scm
+++ b/guix/scripts/publish.scm
@@ -565,13 +565,13 @@ has the given HASH of type ALGO."
                                " speaking.  Welcome!")))
                          port)))))
 
-(define extract-narinfo-hash
-  (let ((regexp (make-regexp "^([a-df-np-sv-z0-9]{32}).narinfo$")))
-    (lambda (str)
-      "Return the hash within the narinfo resource string STR, or false if STR
+(define (extract-narinfo-hash str)
+  "Return the hash within the narinfo resource string STR, or false if STR
 is invalid."
-      (and=> (regexp-exec regexp str)
-             (cut match:substring <> 1)))))
+  (and (string-suffix? ".narinfo" str)
+       (let ((base (string-drop-right str 8)))
+         (and (string-every %nix-base32-charset base)
+              base))))
 
 (define (get-request? request)
   "Return #t if REQUEST uses the GET method."