oe.packagegroup: add code for package groups

This includes some utility functions for dealing with groups of packages
defined in the metadata.  Metadata syntax:

    PACKAGE_GROUP_<group> = "<list of packages>"

If the packages in the group are optional:

    PACKAGE_GROUP_<group>[optional] = "1"

Signed-off-by: Chris Larson <chris_larson@mentor.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/lib/oe/packagegroup.py b/lib/oe/packagegroup.py
new file mode 100644
index 0000000000..6dc9cd7e28
--- /dev/null
+++ b/lib/oe/packagegroup.py
@@ -0,0 +1,15 @@
+def is_optional(group, d):
+    return bool(d.getVarFlag("PACKAGE_GROUP_%s" % group, "optional"))
+
+def packages(groups, d):
+    from itertools import chain
+    return chain.from_iterable(d.getVar("PACKAGE_GROUP_%s" % group, True).split()
+                               for group in groups)
+
+def required_packages(groups, d):
+    req = filter(lambda group: not is_optional(group, d), groups)
+    return " ".join(packages(req, d))
+
+def optional_packages(groups, d):
+    opt = filter(lambda group: is_optional(group, d), groups)
+    return " ".join(packages(opt, d))