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store: 'references/substitutes' caches its results.

* guix/store.scm (%reference-cache): New variable.
(references/substitutes): Use it.
wip-check
Ludovic Courtès 7 years ago
parent
commit
f09aea1b58
  1. 18
      guix/store.scm

18
guix/store.scm

@ -726,14 +726,23 @@ error if there is no such root."
"Return the list of references of PATH."
store-path-list))
(define %reference-cache
;; Brute-force cache mapping store items to their list of references.
;; Caching matters because when building a profile in the presence of
;; grafts, we keep calling 'graft-derivation', which in turn calls
;; 'references/substitutes' many times with the same arguments. Ideally we
;; would use a cache associated with the daemon connection instead (XXX).
(make-hash-table 100))
(define (references/substitutes store items)
"Return the list of list of references of ITEMS; the result has the same
length as ITEMS. Query substitute information for any item missing from the
store at once. Raise a '&nix-protocol-error' exception if reference
information for one of ITEMS is missing."
(let* ((local-refs (map (lambda (item)
(guard (c ((nix-protocol-error? c) #f))
(references store item)))
(or (hash-ref %reference-cache item)
(guard (c ((nix-protocol-error? c) #f))
(references store item))))
items))
(missing (fold-right (lambda (item local-ref result)
(if local-ref
@ -757,7 +766,10 @@ the list of references")
(result '()))
(match items
(()
(reverse result))
(let ((result (reverse result)))
(for-each (cut hash-set! %reference-cache <> <>)
items result)
result))
((item items ...)
(match local-refs
((#f tail ...)

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