[OE-core] [RFC v2 1/9] bluetooth.bbclass: simplify recipe inference of bluetooth provider

[Peter A. Bigot]

Defines ${BLUEZ} to be the provider of bluez services as specified by
DISTRO_FEATURES.

Example recipe fragment:
  inherit bluetooth
  PACKAGECONFIG ??= "${@bb.utils.contains('DISTRO_FEATURES', 'bluetooth', '${BLUEZ}', '', d)}
  PACKAGECONFIG[bluez4] = "--enable-bluetooth,--disable-bluetooth,bluez4"
  PACKAGECONFIG[bluez5] = "--enable-bluez5,--disable-bluez5,bluez5"

Signed-off-by: Peter A. Bigot <pab at pabigot.com>
---
 meta/classes/bluetooth.bbclass | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 meta/classes/bluetooth.bbclass

diff --git a/meta/classes/bluetooth.bbclass b/meta/classes/bluetooth.bbclass
new file mode 100644
index 0000000..f88b4ae
--- /dev/null
+++ b/meta/classes/bluetooth.bbclass
@@ -0,0 +1,14 @@
+# Avoid code duplication in bluetooth-dependent recipes.
+
+# Define a variable that expands to the recipe (package) providing core
+# bluetooth support on the platform:
+# "" if bluetooth is not in DISTRO_FEATURES
+# else "bluez5" if bluez5 is in DISTRO_FEATURES
+# else "bluez4"
+
+# Use this with:
+#  inherit bluetooth
+#  PACKAGECONFIG ??= "${@bb.utils.contains('DISTRO_FEATURES', 'bluetooth', '${BLUEZ}', '', d)}
+#  PACKAGECONFIG[bluez4] = "--enable-bluez4,--disable-bluez4,bluez4"
+
+BLUEZ ?= "${@bb.utils.contains('DISTRO_FEATURES', 'bluetooth', bb.utils.contains('DISTRO_FEATURES', 'bluez5', 'bluez5', 'bluez4', d), '', d)}"
-- 
1.8.5.5