bitbake: implement command to get all possible targets and their dependencies

Add a new command generateTargetsTree() which returns a dependency tree of
possible targets (tasks and recipes) as well as their dependency information.

Optional parameter 'klass' also ensures any recipes which inherit the
specified class path (i.e. 'classes/image.bbclass') are included in the model

Signed-off-by: Joshua Lock <josh@linux.intel.com>

bitbake/lib/bb/event.py

@@ -350,6 +350,15 @@ class DepTreeGenerated(Event):
         Event.__init__(self)
         self._depgraph = depgraph
 
+class TargetsTreeGenerated(Event):
+    """
+    Event when a set of buildable targets has been generated
+    """
+
+    def __init__(self, model):
+        Event.__init__(self)
+        self._model = model
+
 class MsgBase(Event):
     """Base class for messages"""