Subject: [PATCH 1/2] guix: Add compression module.

From: Mathieu Othacehe <[email-masked]>
Date: Thu, 8 Sep 2022 17:30:32 +0200

Move the compression record to a dedicated module so that it can be used
outside (guix scripts pack) module.

* guix/scripts/pack.scm (<compressor>, %compressors, lookup-compressor): Move
it to ...
* guix/compression.scm: ... this new file.
* Makefile.am (MODULES): Add it.
---
 Makefile.am           |  1 +
 guix/compression.scm  | 69 +++++++++++++++++++++++++++++++++++++++++++
 guix/scripts/pack.scm | 46 ++---------------------------
 3 files changed, 72 insertions(+), 44 deletions(-)
 create mode 100644 guix/compression.scm

diff --git a/Makefile.am b/Makefile.am
index 22dcc43f99..65b2ec4612 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -80,6 +80,7 @@ MODULES =					\
   guix/base32.scm				\
   guix/base64.scm				\
   guix/ci.scm					\
+  guix/compression.scm				\
   guix/cpio.scm					\
   guix/cpu.scm					\
   guix/deprecation.scm				\
diff --git a/guix/compression.scm b/guix/compression.scm
new file mode 100644
index 0000000000..10ec4a7cda
--- /dev/null
+++ b/guix/compression.scm
@@ -0,0 +1,69 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2022 Mathieu Othacehe <[email-masked]>
+;;;
+;;; 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 (guix compression)
+  #:use-module (guix gexp)
+  #:use-module (guix ui)
+  #:use-module ((gnu packages compression) #:hide (zip))
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-9)
+  #:use-module (ice-9 match)
+  #:export (compressor
+            compressor?
+            compressor-name
+            compressor-extension
+            compressor-command
+            %compressors
+            lookup-compressor))
+
+;; Type of a compression tool.
+(define-record-type <compressor>
+  (compressor name extension command)
+  compressor?
+  (name       compressor-name)      ;string (e.g., "gzip")
+  (extension  compressor-extension) ;string (e.g., ".lz")
+  (command    compressor-command))  ;gexp (e.g., #~(list "/gnu/store/…/gzip"
+                                    ;                    "-9n" ))
+
+(define %compressors
+  ;; Available compression tools.
+  (list (compressor "gzip"  ".gz"
+                    #~(list #+(file-append gzip "/bin/gzip") "-9n"))
+        (compressor "lzip"  ".lz"
+                    #~(list #+(file-append lzip "/bin/lzip") "-9"))
+        (compressor "xz"    ".xz"
+                    #~(append (list #+(file-append xz "/bin/xz")
+                                    "-e")
+                              (%xz-parallel-args)))
+        (compressor "bzip2" ".bz2"
+                    #~(list #+(file-append bzip2 "/bin/bzip2") "-9"))
+        (compressor "zstd" ".zst"
+                    ;; The default level 3 compresses better than gzip in a
+                    ;; fraction of the time, while the highest level 19
+                    ;; (de)compresses more slowly and worse than xz.
+                    #~(list #+(file-append zstd "/bin/zstd") "-3"))
+        (compressor "none" "" #f)))
+
+(define (lookup-compressor name)
+  "Return the compressor object called NAME.  Error out if it could not be
+found."
+  (or (find (match-lambda
+              (($ <compressor> name*)
+               (string=? name* name)))
+            %compressors)
+      (leave (G_ "~a: compressor not found~%") name)))
diff --git a/guix/scripts/pack.scm b/guix/scripts/pack.scm
index d3ee69840c..0331ec7b04 100644
--- a/guix/scripts/pack.scm
+++ b/guix/scripts/pack.scm
@@ -27,6 +27,7 @@
 (define-module (guix scripts pack)
   #:use-module (guix scripts)
   #:use-module (guix ui)
+  #:use-module (guix compression)
   #:use-module (guix gexp)
   #:use-module ((guix build utils) #:select (%xz-parallel-args))
   #:use-module (guix utils)
@@ -61,13 +62,7 @@ (define-module (guix scripts pack)
   #:use-module (srfi srfi-26)
   #:use-module (srfi srfi-37)
   #:use-module (ice-9 match)
-  #:export (compressor?
-            compressor-name
-            compressor-extension
-            compressor-command
-            %compressors
-            lookup-compressor
-            self-contained-tarball
+  #:export (self-contained-tarball
             debian-archive
             docker-image
             squashfs-image
@@ -75,34 +70,6 @@ (define-module (guix scripts pack)
             %formats
             guix-pack))
 
-;; Type of a compression tool.
-(define-record-type <compressor>
-  (compressor name extension command)
-  compressor?
-  (name       compressor-name)      ;string (e.g., "gzip")
-  (extension  compressor-extension) ;string (e.g., ".lz")
-  (command    compressor-command))  ;gexp (e.g., #~(list "/gnu/store/…/gzip"
-                                    ;                    "-9n" ))
-
-(define %compressors
-  ;; Available compression tools.
-  (list (compressor "gzip"  ".gz"
-                    #~(list #+(file-append gzip "/bin/gzip") "-9n"))
-        (compressor "lzip"  ".lz"
-                    #~(list #+(file-append lzip "/bin/lzip") "-9"))
-        (compressor "xz"    ".xz"
-                    #~(append (list #+(file-append xz "/bin/xz")
-                                    "-e")
-                              (%xz-parallel-args)))
-        (compressor "bzip2" ".bz2"
-                    #~(list #+(file-append bzip2 "/bin/bzip2") "-9"))
-        (compressor "zstd" ".zst"
-                    ;; The default level 3 compresses better than gzip in a
-                    ;; fraction of the time, while the highest level 19
-                    ;; (de)compresses more slowly and worse than xz.
-                    #~(list #+(file-append zstd "/bin/zstd") "-3"))
-        (compressor "none" "" #f)))
-
 ;; This one is only for use in this module, so don't put it in %compressors.
 (define bootstrap-xz
   (compressor "bootstrap-xz" ".xz"
@@ -110,15 +77,6 @@ (define bootstrap-xz
                               "-e")
                         (%xz-parallel-args))))
 
-(define (lookup-compressor name)
-  "Return the compressor object called NAME.  Error out if it could not be
-found."
-  (or (find (match-lambda
-              (($ <compressor> name*)
-               (string=? name* name)))
-            %compressors)
-      (leave (G_ "~a: compressor not found~%") name)))
-
 (define not-config?
   ;; Select (guix …) and (gnu …) modules, except (guix config).
   (match-lambda
-- 
2.37.2