[OE-core] [PATCH v2 2/2] utils.py: helper function for optional include files

[Patrick Ohly]

The main intention is to provide easy-to-use and read helper functions
for including files only when certain distro features are
set. Functionally they are the same as bb.utils.contains and
bb.utils.contains_any.

Distro features are part of the base configuration and thus safe to
use for conditional inclusion in recipes and bbappends, in contrast to
recipe variables which might still change during parsing. Therefore
the check is limited to DISTRO_FEATURES. This is the reason for having
this in OE-core instead of bitbake.

Default values are set so that no redundant parameters have to be
passed for conditional includes. As a secondary usage, the functions
can also be used in boolean checks.

Signed-off-by: Patrick Ohly <patrick.ohly at intel.com>
---
 meta/lib/oe/utils.py | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/meta/lib/oe/utils.py b/meta/lib/oe/utils.py
index 330a5ff..822d0cd 100644
--- a/meta/lib/oe/utils.py
+++ b/meta/lib/oe/utils.py
@@ -126,6 +126,46 @@ def features_backfill(var,d):
     if addfeatures:
         d.appendVar(var, " " + " ".join(addfeatures))
 
+def all_distro_features(d, features, truevalue="1", falsevalue=""):
+    """
+    Returns truevalue if *all* given features are set in DISTRO_FEATURES,
+    else falsevalue. The features can be given as single string or anything
+    that can be turned into a set.
+
+    This is a shorter, more flexible version of
+    bb.utils.contains("DISTRO_FEATURES", features, truevalue, falsevalue, d).
+
+    Without explicit true/false values it can be used directly where
+    Python expects a boolean:
+       if oe.utils.all_distro_features(d, "foo bar"):
+           bb.fatal("foo and bar are mutually exclusive DISTRO_FEATURES")
+
+    With just a truevalue, it can be used to include files that are meant to be
+    used only when requested via DISTRO_FEATURES:
+       require ${@ oe.utils.all_distro_features(d, "foo bar", "foo-and-bar.inc")
+    """
+    return bb.utils.contains("DISTRO_FEATURES", features, truevalue, falsevalue, d)
+
+def any_distro_features(d, features, truevalue="1", falsevalue=""):
+    """
+    Returns truevalue if at least *one* of the given features is set in DISTRO_FEATURES,
+    else falsevalue. The features can be given as single string or anything
+    that can be turned into a set.
+
+    This is a shorter, more flexible version of
+    bb.utils.contains_any("DISTRO_FEATURES", features, truevalue, falsevalue, d).
+
+    Without explicit true/false values it can be used directly where
+    Python expects a boolean:
+       if not oe.utils.any_distro_features(d, "foo bar"):
+           bb.fatal("foo, bar or both must be set in DISTRO_FEATURES")
+
+    With just a truevalue, it can be used to include files that are meant to be
+    used only when requested via DISTRO_FEATURES:
+       require ${@ oe.utils.any_distro_features(d, "foo bar", "foo-or-bar.inc")
+
+    """
+    return bb.utils.contains_any("DISTRO_FEATURES", features, truevalue, falsevalue, d)
 
 def packages_filter_out_system(d):
     """
-- 
git-series 0.9.1