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derivations: Micro-optimize 'derivation'.

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* guix/derivations.scm (derivation->string): New procedure.
  (derivation-hash, derivation): Use it.
  Memoization here yields a 5% improvement on "guix build -e '(@ (gnu
  packages emacs) emacs)' -n --no-substitutes".
This commit is contained in:
Ludovic Courtès 2014-04-29 18:13:10 +02:00
parent 2c6b7c7d55
commit be4e38fb6f
1 changed files with 10 additions and 5 deletions
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15
guix/derivations.scm
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@ -435,6 +435,14 @@ that form."
port)
(display ")" port))))
(define derivation->string
(memoize
(lambda (drv)
"Return the external representation of DRV as a string."
(with-fluids ((%default-port-encoding "UTF-8"))
(call-with-output-string
(cut write-derivation drv <>))))))
(define* (derivation->output-path drv #:optional (output "out"))
"Return the store path of its output OUTPUT."
(let ((outputs (derivation-outputs drv)))
@ -517,9 +525,7 @@ in SIZE bytes."
;; the SHA256 port's `write' method gets called for every single
;; character.
(sha256
(with-fluids ((%default-port-encoding "UTF-8"))
(string->utf8 (call-with-output-string
(cut write-derivation drv <>)))))))))))
(string->utf8 (derivation->string drv)))))))))
(define (store-path type hash name) ; makeStorePath
"Return the store path for NAME/HASH/TYPE."
@ -685,8 +691,7 @@ derivations where the costs of data transfers would outweigh the benefits."
(drv (add-output-paths drv-masked)))
(let ((file (add-text-to-store store (string-append name ".drv")
(call-with-output-string
(cut write-derivation drv <>))
(derivation->string drv)
(map derivation-input-path
inputs))))
(set-file-name drv file))))