[PATCH v2] use xz and gzip on host (outside chroot)

[Felix Moessbauer <felix.moessbauer@siemens.com>]

From: Adriaan Schmidt <adriaan.schmidt@siemens.com>

This patch significantly speeds up the final image compression
as the compression itself is no longer emulated.

For gzip, no additional dep has to be installed on the system,
for xz the xz-utils package has to be installed but this will
be required from bitbake 2.0 on anyways.

Signed-off-by: Adriaan Schmidt <adriaan.schmidt@siemens.com>
Acked-by: Felix Moessbauer <felix.moessbauer@siemens.com>
---
 doc/user_manual.md              | 3 ++-
 meta/classes/imagetypes.bbclass | 8 ++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/doc/user_manual.md b/doc/user_manual.md
index 546ae75c..932bfbe5 100644
--- a/doc/user_manual.md
+++ b/doc/user_manual.md
@@ -83,7 +83,8 @@ apt install \
   reprepro \
   sudo \
   git-buildpackage \
-  pristine-tar
+  pristine-tar \
+  xz-utils
 ```
 
 Additional setup is required since `sbuild` is now used for package build.
diff --git a/meta/classes/imagetypes.bbclass b/meta/classes/imagetypes.bbclass
index 1e8e223d..319e9dc8 100644
--- a/meta/classes/imagetypes.bbclass
+++ b/meta/classes/imagetypes.bbclass
@@ -95,13 +95,13 @@ IMAGE_CMD_ubi[depends] = "${PN}:do_transform_template"
 # image conversions
 IMAGE_CONVERSIONS = "gz xz"
 
-CONVERSION_CMD_gz = "${SUDO_CHROOT} sh -c 'gzip -f -9 -n -c --rsyncable ${IMAGE_FILE_CHROOT} > ${IMAGE_FILE_CHROOT}.gz'"
-CONVERSION_DEPS_gz = "gzip"
+CONVERSION_CMD_gz ?= "gzip -f -9 -n -c --rsyncable ${IMAGE_FILE_HOST} > ${IMAGE_FILE_HOST}.gz"
+CONVERSION_DEPS_gz ?= ""
 
 XZ_MEMLIMIT ?= "50%"
 XZ_THREADS ?= "${@oe.utils.cpu_count(at_least=2)}"
 XZ_THREADS[vardepvalue] = "1"
 XZ_OPTIONS ?= "--memlimit=${XZ_MEMLIMIT} --threads=${XZ_THREADS}"
 XZ_OPTIONS[vardepsexclude] += "XZ_MEMLIMIT XZ_THREADS"
-CONVERSION_CMD_xz = "${SUDO_CHROOT} sh -c 'xz -c ${XZ_OPTIONS} ${IMAGE_FILE_CHROOT} > ${IMAGE_FILE_CHROOT}.xz'"
-CONVERSION_DEPS_xz = "xz-utils"
+CONVERSION_CMD_xz ?= "xz -c ${XZ_OPTIONS} ${IMAGE_FILE_HOST} > ${IMAGE_FILE_HOST}.xz"
+CONVERSION_DEPS_xz ?= ""
-- 
2.30.2