From ed3592a9809fad73e9caee2d321d06446d78c8d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Sun, 11 Jan 2015 23:04:07 +0100
Subject: [PATCH] derivations: Use sets for 'derivations-prerequisites'.
This yields a 46% improvement in 'derivation-prerequisites' invocations
on the Emacs derivation.
* guix/derivations.scm (derivation-prerequisites): Add 'input-set'
variable, and use it in iterations.
---
guix/derivations.scm | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/guix/derivations.scm b/guix/derivations.scm
index ec438e833c4..2f015089a3e 100644
--- a/guix/derivations.scm
+++ b/guix/derivations.scm
@@ -31,6 +31,7 @@ (define-module (guix derivations)
#:use-module (guix hash)
#:use-module (guix base32)
#:use-module (guix records)
+ #:use-module (guix sets)
#:export (<derivation>
derivation?
derivation-outputs
@@ -162,16 +163,18 @@ (define (derivation-input-output-paths input)
(define (derivation-prerequisites drv)
"Return the list of derivation-inputs required to build DRV, recursively."
- (let loop ((drv drv)
- (result '()))
- (let ((inputs (remove (cut member <> result) ; XXX: quadratic
+ (let loop ((drv drv)
+ (result '())
+ (input-set (set)))
+ (let ((inputs (remove (cut set-contains? input-set <>)
(derivation-inputs drv))))
- (fold loop
- (append inputs result)
- (map (lambda (i)
- (call-with-input-file (derivation-input-path i)
- read-derivation))
- inputs)))))
+ (fold2 loop
+ (append inputs result)
+ (fold set-insert input-set inputs)
+ (map (lambda (i)
+ (call-with-input-file (derivation-input-path i)
+ read-derivation))
+ inputs)))))
(define (offloadable-derivation? drv)
"Return true if DRV can be offloaded, false otherwise."
--
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