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gnupdate: Improve error handling for pipes.

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* maintainers/scripts/gnu/gnupdate (pipe-failed?): New procedure.
  (nix-prefetch-url): Use it.
  (gnupdate)[nixpkgs->snix]: New procedure.
  Use it.

svn path=/nixpkgs/trunk/; revision=26160
This commit is contained in:
Ludovic Courtès 2011-03-04 13:18:56 +00:00
parent f084b30926
commit cc02933305
1 changed files with 32 additions and 12 deletions
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44
maintainers/scripts/gnu/gnupdate
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@ -277,18 +277,27 @@ exec ${GUILE-guile} -L "$PWD" -l "$0" \
"--strict" "--eval-only" "--xml"
script)))
(define (pipe-failed? pipe)
"Close pipe and return its status if it failed."
(let ((status (close-pipe pipe)))
(if (or (status:term-sig status)
(not (= (status:exit-val status) 0)))
status
#f)))
(define (nix-prefetch-url url)
;; Download URL in the Nix store and return the base32-encoded SHA256 hash
;; of the file at URL
(let* ((pipe (open-pipe* OPEN_READ "nix-prefetch-url" url))
(hash (read-line pipe)))
(close-pipe pipe)
(if (eof-object? hash)
(if (or (pipe-failed? pipe)
(eof-object? hash))
(values #f #f)
(let* ((pipe (open-pipe* OPEN_READ "nix-store" "--print-fixed-path"
"sha256" hash (basename url)))
"sha256" hash (basename url)))
(path (read-line pipe)))
(if (eof-object? path)
(if (or (pipe-failed? pipe)
(eof-object? path))
(values #f #f)
(values (string-trim-both hash) (string-trim-both path)))))))
@ -815,20 +824,31 @@ pairs. Example: (\"mit-scheme-9.0.1\" . \"/gnu/mit-scheme/stable.pkg/9.0.1\").
(define (gnupdate . args)
;; Assume Nixpkgs is under $NIXPKGS or ~/src/nixpkgs.
(define (nixpkgs->snix xml-file)
(format (current-error-port) "evaluating Nixpkgs...~%")
(let* ((home (getenv "HOME"))
(xml (if xml-file
(open-input-file xml-file)
(open-nixpkgs (or (getenv "NIXPKGS")
(string-append home "/src/nixpkgs")))))
(snix (xml->snix xml)))
(if (not xml-file)
(let ((status (pipe-failed? xml)))
(if status
(begin
(format (current-error-port) "`nix-instantiate' failed: ~A~%"
status)
(exit 1)))))
snix))
(let* ((opts (args-fold (cdr args) %options
(lambda (opt name arg result)
(error "unrecognized option `~A'" name))
(lambda (operand result)
(error "extraneous argument `~A'" operand))
'()))
(home (getenv "HOME"))
(path (or (getenv "NIXPKGS")
(string-append home "/src/nixpkgs")))
(snix (begin
(format (current-error-port) "parsing XML...~%")
(xml->snix
(or (and=> (assoc-ref opts 'xml-file) open-input-file)
(open-nixpkgs path)))))
(snix (nixpkgs->snix (assoc-ref opts 'xml-file)))
(packages (match snix
(('snix _ ('attribute-set attributes))
attributes)