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Optimize `write-derivation' and `derivation-path->output-path'. 

* guix/derivations.scm (write-derivation): Explicitly use
  `simple-format'.
  (derivation-path->output-path): Memoize.
This commit is contained in:
Ludovic Courtès 2012-09-01 19:21:06 +02:00
parent f39bd08ad2
commit aaa848f3af
1 changed files with 12 additions and 5 deletions
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11
guix/derivations.scm
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@ -200,6 +200,10 @@ available in STORE, recursively."
"Write the ATerm-like serialization of DRV to PORT. See Section 2.4 of
Eelco Dolstra's PhD dissertation for an overview of a previous version of
that form."
;; Make sure we're using the faster implementation.
(define format simple-format)
(define (list->string lst)
(string-append "[" (string-join lst ",") "]"))
@ -269,12 +273,15 @@ that form."
(string<? (car e1) (car e2))))))
(display ")" port))))
(define* (derivation-path->output-path path #:optional (output "out"))
(define derivation-path->output-path
;; This procedure is called frequently, so memoize it.
(memoize
(lambda* (path #:optional (output "out"))
"Read the derivation from PATH (`/nix/store/xxx.drv'), and return the store
path of its output OUTPUT."
(let* ((drv (call-with-input-file path read-derivation))
(outputs (derivation-outputs drv)))
(and=> (assoc-ref outputs output) derivation-output-path)))
(and=> (assoc-ref outputs output) derivation-output-path)))))
;;;