distrooverrides: Move back to classes whilst it's usage is clarified

(From OE-Core rev: eb56f89a9b2163bdb8c91dbdc33696fea052d032)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/meta/classes/distrooverrides.bbclass b/meta/classes/distrooverrides.bbclass
new file mode 100644
index 0000000000..8d9d7cda7d
--- /dev/null
+++ b/meta/classes/distrooverrides.bbclass
@@ -0,0 +1,38 @@
+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: MIT
+#
+
+# Turns certain DISTRO_FEATURES into overrides with the same
+# name plus a df- prefix. Ensures that these special
+# distro features remain set also for native and nativesdk
+# recipes, so that these overrides can also be used there.
+#
+# This makes it simpler to write .bbappends that only change the
+# task signatures of the recipe if the change is really enabled,
+# for example with:
+#   do_install:append:df-my-feature () { ... }
+# where "my-feature" is a DISTRO_FEATURE.
+#
+# The class is meant to be used in a layer.conf or distro
+# .inc file with:
+# INHERIT += "distrooverrides"
+# DISTRO_FEATURES_OVERRIDES += "my-feature"
+#
+# Beware that this part of OVERRIDES changes during parsing, so usage
+# of these overrides should be limited to .bb and .bbappend files,
+# because then DISTRO_FEATURES is final.
+
+DISTRO_FEATURES_OVERRIDES ?= ""
+DISTRO_FEATURES_OVERRIDES[doc] = "A space-separated list of <feature> entries. \
+Each entry is added to OVERRIDES as df-<feature> if <feature> is in DISTRO_FEATURES."
+
+DISTRO_FEATURES_FILTER_NATIVE:append = " ${DISTRO_FEATURES_OVERRIDES}"
+DISTRO_FEATURES_FILTER_NATIVESDK:append = " ${DISTRO_FEATURES_OVERRIDES}"
+
+# If DISTRO_FEATURES_OVERRIDES or DISTRO_FEATURES show up in a task
+# signature because of this line, then the task dependency on
+# OVERRIDES itself should be fixed. Excluding these two variables
+# with DISTROOVERRIDES[vardepsexclude] would just work around the problem.
+DISTROOVERRIDES .= "${@ ''.join([':df-' + x for x in sorted(set(d.getVar('DISTRO_FEATURES_OVERRIDES').split()) & set((d.getVar('DISTRO_FEATURES') or '').split()))]) }"