diff options
Diffstat (limited to 'guix/utils.scm')
| -rw-r--r-- | guix/utils.scm | 48 |
1 files changed, 47 insertions, 1 deletions
diff --git a/guix/utils.scm b/guix/utils.scm index 0b09affffd..7c8e914c01 100644 --- a/guix/utils.scm +++ b/guix/utils.scm @@ -25,6 +25,7 @@ #:use-module (srfi srfi-60) #:use-module (rnrs bytevectors) #:use-module ((rnrs io ports) #:select (put-bytevector)) + #:use-module ((guix build utils) #:select (dump-port)) #:use-module (ice-9 vlist) #:use-module (ice-9 format) #:autoload (ice-9 popen) (open-pipe*) @@ -63,7 +64,8 @@ string-tokenize* file-extension call-with-temporary-output-file - fold2)) + fold2 + filtered-port)) ;;; @@ -156,6 +158,50 @@ evaluate to a simple datum." ;;; +;;; Filtering & pipes. +;;; + +(define (filtered-port command input) + "Return an input port where data drained from INPUT is filtered through +COMMAND (a list). In addition, return a list of PIDs that the caller must +wait." + (let loop ((input input) + (pids '())) + (if (file-port? input) + (match (pipe) + ((in . out) + (match (primitive-fork) + (0 + (close-port in) + (close-port (current-input-port)) + (dup2 (fileno input) 0) + (close-port (current-output-port)) + (dup2 (fileno out) 1) + (apply execl (car command) command)) + (child + (close-port out) + (values in (cons child pids)))))) + + ;; INPUT is not a file port, so fork just for the sake of tunneling it + ;; through a file port. + (match (pipe) + ((in . out) + (match (primitive-fork) + (0 + (dynamic-wind + (const #t) + (lambda () + (close-port in) + (dump-port input out)) + (lambda () + (false-if-exception (close out)) + (primitive-exit 0)))) + (child + (close-port out) + (loop in (cons child pids))))))))) + + +;;; ;;; Nixpkgs. ;;; |