[PATCH v2 2/5] ref-manual: variables.rst: document spdx-create class variables

[michael.opdenacker@bootlin.com]

From: Michael Opdenacker <michael.opdenacker@bootlin.com>

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
---
 documentation/ref-manual/variables.rst | 82 ++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index dc6eccb314..0cc73a234c 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -7284,6 +7284,88 @@ system and gives an overview of their function and contents.
 
          You can specify only a single URL in :term:`SOURCE_MIRROR_URL`.
 
+   :term:`SPDX_ARCHIVE_PACKAGED`
+      This option allows to add to :term:`SPDX` output compressed archives
+      of the files in the generated target packages.
+
+      Such archives are available in
+      ``tmp/deploy/spdx/MACHINE/packages/packagename.tar.zst``
+      under the :term:`Build Directory`.
+
+      Enable this option as follows::
+
+         SPDX_ARCHIVE_PACKAGED = "1"
+
+      According to our tests on release 4.1 "langdale", building
+      ``core-image-minimal`` for the ``qemux86-64`` machine, enabling this
+      option multiplied the size of the ``tmp/deploy/spdx`` directory by a
+      factor of 13 (+1.6 GiB for this image), compared to just using the
+      :ref:`create-spdx <ref-classes-create-spdx>` class with no option.
+
+      Note that this option doesn't increase the size of :term:`SPDX`
+      files in ``tmp/deploy/images/MACHINE``.
+
+   :term:`SPDX_ARCHIVE_SOURCES`
+      This option allows to add to :term:`SPDX` output compressed archives
+      of the sources for packages installed on the target. It currently
+      only works when :term:`SPDX_INCLUDE_SOURCES` is set.
+
+      This is one way of fulfilling "source code access" license
+      requirements.
+
+      Such source archives are available in
+      ``tmp/deploy/spdx/MACHINE/recipes/recipe-packagename.tar.zst``
+      under the :term:`Build Directory`.
+
+      Enable this option as follows::
+
+         SPDX_INCLUDE_SOURCES = "1"
+         SPDX_ARCHIVE_SOURCES = "1"
+
+      According to our tests on release 4.1 "langdale", building
+      ``core-image-minimal`` for the ``qemux86-64`` machine, enabling
+      these options multiplied the size of the ``tmp/deploy/spdx``
+      directory by a factor of 11 (+1.4 GiB for this image),
+      compared to just using the :ref:`create-spdx <ref-classes-create-spdx>`
+      class with no option.
+
+      Note that using this option only marginally increases the size
+      of the :term:`SPDX` output in ``tmp/deploy/images/MACHINE/``
+      (+ 0.07\% with the tested image), compared to just enabling
+      :term:`SPDX_INCLUDE_SOURCES`.
+
+   :term:`SPDX_INCLUDE_SOURCES`
+      This option allows to add a description of the source files used to build
+      the host tools and the target packages, to the ``spdx.json`` files in
+      ``tmp/deploy/spdx/MACHINE/recipes/`` under the :term:`Build Directory`.
+      As a consequence, the ``spdx.json`` files under the ``by-namespace`` and
+      ``packages`` subdirectories in ``tmp/deploy/spdx/MACHINE`` are also
+      modified to include references to such source file descriptions.
+
+      Enable this option as follows::
+
+         SPDX_INCLUDE_SOURCES = "1"
+
+      According to our tests on release 4.1 "langdale", building
+      ``core-image-minimal`` for the ``qemux86-64`` machine, enabling
+      this option multiplied the total size of the ``tmp/deploy/spdx``
+      directory by a factor of 3  (+291 MiB for this image),
+      and the size of the ``IMAGE-MACHINE.spdx.tar.zst`` in
+      ``tmp/deploy/images/MACHINE`` by a factor of 130 (+15 MiB for this
+      image), compared to just using the
+      :ref:`create-spdx <ref-classes-create-spdx>` class with no option.
+
+   :term:`SPDX_PRETTY`
+      This option makes the SPDX output more human-readable, using
+      identation and newlines, instead of the default output in a
+      single line::
+
+         SPDX_PRETTY = "1"
+
+      The generated SPDX files are approximately 20% bigger, but
+      this option is recommended if you want to inspect the SPDX
+      output files with a text editor.
+
    :term:`SPDXLICENSEMAP`
       Maps commonly used license names to their SPDX counterparts found in
       ``meta/files/common-licenses/``. For the default :term:`SPDXLICENSEMAP`
-- 
2.34.1