;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018 Mathieu Othacehe <m.othacehe@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu installer newt timezone)
  #:use-module (gnu installer steps)
  #:use-module (gnu installer timezone)
  #:use-module (gnu installer newt page)
  #:use-module (guix i18n)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (ice-9 match)
  #:use-module (ice-9 receive)
  #:use-module (newt)
  #:export (run-timezone-page))

;; Information textbox width.
(define info-textbox-width (make-parameter 40))

(define (fill-timezones listbox timezones)
  "Fill the given LISTBOX with TIMEZONES. Return an association list
correlating listbox keys with timezones."
  (map (lambda (timezone)
         (let ((key (append-entry-to-listbox listbox timezone)))
           (cons key timezone)))
       timezones))

(define (run-timezone-page zonetab)
  "Run a page displaying available timezones, grouped by regions. The user is
invited to select a timezone. The selected timezone, under Posix format is
returned."
  (define (all-but-last list)
    (reverse (cdr (reverse list))))

  (define (run-page timezone-tree)
    (define (loop path)
      ;; XXX: Translation of time zones isn't perfect here because the
      ;; "iso_3166-1" domain contains translation for "territories" (like
      ;; "Antarctic") but not for continents (like "Africa").
      (let ((timezones (locate-children timezone-tree path)))
        (run-listbox-selection-page
         #:title (G_ "Timezone")
         #:info-text (G_ "Please select a timezone.")
         #:listbox-items timezones
         #:listbox-item->text (cut gettext <> "iso_3166-1")
         #:button-text (if (null? path)
                           (G_ "Exit")
                           (G_ "Back"))
         #:button-callback-procedure
         (if (null? path)
             (lambda _
               (abort-to-prompt 'installer-step 'abort))
             (lambda _
               (loop (all-but-last path))))
         #:listbox-callback-procedure
         (lambda (timezone)
           (let* ((timezone* (append path (list timezone)))
                  (tz (timezone->posix-tz timezone*)))
             (if (timezone-has-child? timezone-tree timezone*)
                 (loop timezone*)
                 tz))))))
    (loop '()))

  (let ((timezone-tree (zonetab->timezone-tree zonetab)))
    (run-page timezone-tree)))
o ~4% of the space savings
afforded by deduplication.

Not considering these files for deduplication speeds up file insertion
in the store and, more importantly, leaves 'removeUnusedLinks' with
fewer entries to traverse, thereby speeding it up proportionally.

Partly fixes &lt;https://issues.guix.gnu.org/24937&gt;.

* config-daemon.ac: Remove symlink hard link check and CAN_LINK_SYMLINK
definition.
* guix/store/deduplication.scm (%deduplication-minimum-size): New
variable.
(deduplicate)[loop]: Do not recurse when FILE's size is below
%DEDUPLICATION-MINIMUM-SIZE.
(dump-port): New procedure.
(dump-file/deduplicate)[hash]: Turn into...
[dump-and-compute-hash]: ... this thunk.
Call 'deduplicate' only when SIZE is greater than
%DEDUPLICATION-MINIMUM-SIZE; otherwise call 'dump-port'.
* nix/libstore/gc.cc (LocalStore::removeUnusedLinks): Drop files where
st.st_size &lt; deduplicationMinSize.
* nix/libstore/local-store.hh (deduplicationMinSize): New declaration.
* nix/libstore/optimise-store.cc (deduplicationMinSize): New variable.
(LocalStore::optimisePath_): Return when PATH is a symlink or smaller
than 'deduplicationMinSize'.
* tests/derivations.scm ("identical files are deduplicated"): Produce
files bigger than %DEDUPLICATION-MINIMUM-SIZE.
* tests/nar.scm ("restore-file-set with directories (signed, valid)"):
Likewise.
* tests/store-deduplication.scm ("deduplicate, below %deduplication-minimum-size"):
New test.
("deduplicate", "deduplicate, ENOSPC"): Produce files bigger than
%DEDUPLICATION-MINIMUM-SIZE.
* tests/store.scm ("substitute, deduplication"): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>