From f20fd89fc02454f41ec4844c3ddf03b7edbe2639 Mon Sep 17 00:00:00 2001
From: Pavol Rusnak <pavol@rusnak.io>
Date: Fri, 24 Apr 2020 18:12:42 +0200
Subject: [PATCH] iso-image: use zstd for compression

---
 nixos/lib/make-iso9660-image.nix             | 4 ++--
 nixos/lib/make-iso9660-image.sh              | 9 +++++++--
 nixos/modules/installer/cd-dvd/iso-image.nix | 2 +-
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/nixos/lib/make-iso9660-image.nix b/nixos/lib/make-iso9660-image.nix
index 0f3f2b5b523..be8ad9912db 100644
--- a/nixos/lib/make-iso9660-image.nix
+++ b/nixos/lib/make-iso9660-image.nix
@@ -34,7 +34,7 @@
 , # The path (outside the ISO file system) of the isohybrid-mbr image.
   isohybridMbrImage ? ""
 
-, # Whether to compress the resulting ISO image with bzip2.
+, # Whether to compress the resulting ISO image with zstd.
   compressImage ? false
 
 , # The volume ID.
@@ -48,7 +48,7 @@ assert usbBootable -> isohybridMbrImage != "";
 stdenv.mkDerivation {
   name = isoName;
   builder = ./make-iso9660-image.sh;
-  buildInputs = [ xorriso syslinux ];
+  buildInputs = [ xorriso syslinux zstd ];
 
   inherit isoName bootable bootImage compressImage volumeID efiBootImage efiBootable isohybridMbrImage usbBootable;
 
diff --git a/nixos/lib/make-iso9660-image.sh b/nixos/lib/make-iso9660-image.sh
index d4633d2c8d1..eb9edcd7026 100644
--- a/nixos/lib/make-iso9660-image.sh
+++ b/nixos/lib/make-iso9660-image.sh
@@ -129,9 +129,14 @@ fi
 
 if test -n "$compressImage"; then
     echo "Compressing image..."
-    bzip2 $out/iso/$isoName
+    zstd -T$NIX_BUILD_CORES $out/iso/$isoName
 fi
 
 mkdir -p $out/nix-support
 echo $system > $out/nix-support/system
-echo "file iso $out/iso/$isoName" >> $out/nix-support/hydra-build-products
+
+if test -n "$compressImage"; then
+    echo "file iso $out/iso/$isoName.zst" >> $out/nix-support/hydra-build-products
+else
+    echo "file iso $out/iso/$isoName" >> $out/nix-support/hydra-build-products
+fi
diff --git a/nixos/modules/installer/cd-dvd/iso-image.nix b/nixos/modules/installer/cd-dvd/iso-image.nix
index cce7cc235ec..1cd2252ecf2 100644
--- a/nixos/modules/installer/cd-dvd/iso-image.nix
+++ b/nixos/modules/installer/cd-dvd/iso-image.nix
@@ -413,7 +413,7 @@ in
       default = false;
       description = ''
         Whether the ISO image should be compressed using
-        <command>bzip2</command>.
+        <command>zstd</command>.
       '';
     };