Change how MorphologyLoader instances are created

Loading .morph files is becoming a bit more complicated, as we need to
deal with the VERSION file, and possibly soon with a DEFAULTS file as
well.

The logic of loading and parsing .morph files is done either in the
sourceresolver module, or the morphloader module. This change means that
all users of the latter module can use the get hold of a
MorphologyLoader instance with VERSION already parsed. If DEFAULTS is
added then it is also simple to parse DEFAULTS.

Change-Id: Ib33756e9dbd078e38f12dd7f776c89584b178959

1 files changed, 13 insertions, 10 deletions

diff --git a/morphlib/buildbranch.py b/morphlib/buildbranch.py
index e16bf2b4..6cec97fb 100644
--- a/morphlib/buildbranch.py
+++ b/morphlib/buildbranch.py
@@ -159,27 +159,31 @@ class BuildBranch(object):
             sha1 = gd.store_blob(loader.save_to_string(morphology))
             yield 0o100644, sha1, morphology.filename
 
+    def get_morphology_loader(self):
+        if self._sb:
+            return self._sb.get_morphology_loader()
+        else:
+            return self._root.get_morphology_loader()
+
     def load_all_morphologies(self, loader):
         if self._sb:
-            return self._sb.load_all_morphologies(loader)
+            return self._sb.load_all_morphologies()
         else:
-            return self._root.load_all_morphologies(loader)
+            return self._root.load_all_morphologies()
 
-    def inject_build_refs(self, loader, use_local_repos,
-                          inject_cb=lambda **kwargs: None):
+    def inject_build_refs(self, use_local_repos, inject_cb=lambda **kwargs:
+                          None):
         '''Update system and stratum morphologies to point to our branch.
 
         For all edited repositories, this alter the temporary GitIndex
         of the morphs repositories to point their temporary build branch
         versions.
 
-        `loader` is a MorphologyLoader that is used to convert morphology
-        files into their in-memory representations and back again.
-
         '''
         root_repo = self._root.remote_url
         root_ref = self._root.HEAD
         morphs = morphlib.morphset.MorphologySet()
+        loader = self.get_morphology_loader()
 
         for morph in self.load_all_morphologies(loader):
             morphs.add_morphology(morph)
@@ -362,7 +366,7 @@ class BuildBranch(object):
 
 
 @contextlib.contextmanager
-def pushed_build_branch(bb, loader, changes_need_pushing, name, email,
+def pushed_build_branch(bb, changes_need_pushing, name, email,
                         build_uuid, status):
     with contextlib.closing(bb) as bb:
         def report_add(gd, build_ref, changed):
@@ -385,8 +389,7 @@ def pushed_build_branch(bb, loader, changes_need_pushing, name, email,
             status(msg='Injecting temporary build refs '\
                            'into morphologies in %(dirname)s',
                        dirname=gd.dirname, chatty=True)
-        bb.inject_build_refs(loader=loader,
-                             use_local_repos=not changes_need_pushing,
+        bb.inject_build_refs(use_local_repos=not changes_need_pushing,
                              inject_cb=report_inject)
 
         def report_commit(gd, build_ref):