diff options
Diffstat (limited to 'guix/utils.scm')
-rw-r--r-- | guix/utils.scm | 46 |
1 files changed, 45 insertions, 1 deletions
diff --git a/guix/utils.scm b/guix/utils.scm index a5f64f97a9..2ffecbfab9 100644 --- a/guix/utils.scm +++ b/guix/utils.scm @@ -19,9 +19,12 @@ (define-module (guix utils) #:use-module (srfi srfi-1) #:use-module (srfi srfi-26) + #:use-module (srfi srfi-39) #:use-module (srfi srfi-60) #:use-module (rnrs bytevectors) #:use-module (ice-9 format) + #:autoload (ice-9 popen) (open-pipe*) + #:autoload (ice-9 rdelim) (read-line) #:use-module ((chop hash) #:select (bytevector-hash hash-method/sha256)) @@ -29,7 +32,12 @@ bytevector->base32-string bytevector->nix-base32-string bytevector->base16-string - sha256)) + sha256 + + %nixpkgs-directory + nixpkgs-derivation + + memoize)) ;;; @@ -198,3 +206,39 @@ the previous application or INIT." "Return the SHA256 of BV as a bytevector." (bytevector-hash hash-method/sha256 bv)) + + +;;; +;;; Nixpkgs. +;;; + +(define %nixpkgs-directory + (make-parameter (getenv "NIXPKGS"))) + +(define (nixpkgs-derivation attribute) + "Return the derivation path of ATTRIBUTE in Nixpkgs." + (let* ((p (open-pipe* OPEN_READ "nix-instantiate" "-A" + attribute (%nixpkgs-directory))) + (l (read-line p)) + (s (close-pipe p))) + (and (zero? (status:exit-val s)) + (not (eof-object? l)) + l))) + + +;;; +;;; Miscellaneous. +;;; + +(define (memoize proc) + "Return a memoizing version of PROC." + (let ((cache (make-hash-table))) + (lambda args + (let ((results (hash-ref cache args))) + (if results + (apply values results) + (let ((results (call-with-values (lambda () + (apply proc args)) + list))) + (hash-set! cache args results) + (apply values results))))))) |