Replace builder order graph with just a single artifact

The artifact's build dependencies replace the build order graph
from previously.

4 files changed, 54 insertions, 36 deletions

diff --git a/morphlib/artifact.py b/morphlib/artifact.py
index ccde11d4..3bb2a520 100644
--- a/morphlib/artifact.py
+++ b/morphlib/artifact.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2012  Codethink Limited
+# Copyright (C) 2012, 2013  Codethink Limited
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -63,3 +63,24 @@ class Artifact(object):
 
     def __str__(self):  # pragma: no cover
         return '%s|%s' % (self.source, self.name)
+
+    def walk(self): # pragma: no cover
+        '''Return list of an artifact and its build dependencies.
+        
+        The artifacts are returned in depth-first order: an artifact
+        is returned only after all of its dependencies.
+        
+        '''
+        
+        done = set()
+        
+        def depth_first(a):
+            for dep in a.dependencies:
+                for ret in depth_first(dep):
+                    yield ret
+            if a not in done:
+                done.add(a)
+                yield a
+
+        return list(depth_first(self))
+
diff --git a/morphlib/buildcommand.py b/morphlib/buildcommand.py
index 907676fa..c12735bb 100644
--- a/morphlib/buildcommand.py
+++ b/morphlib/buildcommand.py
@@ -48,8 +48,8 @@ class BuildCommand(object):
         for repo_name, ref, filename in self.app.itertriplets(args):
             self.app.status(msg='Building %(repo_name)s %(ref)s %(filename)s',
                             repo_name=repo_name, ref=ref, filename=filename)
-            order = self.compute_build_order(repo_name, ref, filename)
-            self.build_in_order(order)
+            artifact = self.get_artifact_object(repo_name, ref, filename)
+            self.build_in_order(artifact)
 
         self.app.status(msg='Build ends successfully', chatty=True)
 
@@ -72,7 +72,14 @@ class BuildCommand(object):
     def new_repo_caches(self):
         return morphlib.util.new_repo_caches(self.app)
 
-    def compute_build_order(self, repo_name, ref, filename):
+    def get_artifact_object(self, repo_name, ref, filename):
+        '''Create an Artifact object representing the given triplet.'''
+        
+        order = self._compute_build_order(repo_name, ref, filename)
+        artifact = order.groups[-1][-1]
+        return artifact
+
+    def _compute_build_order(self, repo_name, ref, filename):
         '''Compute build order for a triplet.'''
         self.app.status(msg='Figuring out the right build order')
 
@@ -158,24 +165,13 @@ class BuildCommand(object):
                          other.morphology['kind'],
                          wanted))
 
-    def build_in_order(self, order):
+    def build_in_order(self, artifact):
         '''Build everything specified in a build order.'''
         self.app.status(msg='Building according to build ordering',
                         chatty=True)
-        for group in order.groups:
-            self.build_artifacts(group)
-
-    def build_artifacts(self, artifacts):
-        '''Build a set of artifact.
-
-        Typically, this would be a build group, but might be anything.
-        At this level of abstraction we don't care.
 
-        '''
-
-        self.app.status(msg='Building a set of artifacts', chatty=True)
-        for artifact in artifacts:
-            self.build_artifact(artifact)
+        for a in artifact.walk():
+            self.build_artifact(a)
 
     def build_artifact(self, artifact):
         '''Build one artifact.
@@ -287,7 +283,9 @@ class BuildCommand(object):
                 self.app.status(msg='Fetching to local cache: '
                                     'artifact %(name)s',
                                 name=artifact.name)
-                copy(self.rac.get(artifact), self.lac.put(artifact))
+                rac_file = self.rac.get(artifact)
+                lac_file = self.lac.put(artifact)
+                copy(rac_file, lac_file)
 
             if artifact.source.morphology.needs_artifact_metadata_cached:
                 if not self.lac.has_artifact_metadata(artifact, 'meta'):
diff --git a/morphlib/plugins/deploy_plugin.py b/morphlib/plugins/deploy_plugin.py
index 79715e13..f9a345ff 100644
--- a/morphlib/plugins/deploy_plugin.py
+++ b/morphlib/plugins/deploy_plugin.py
@@ -100,11 +100,10 @@ class DeployPlugin(cliapp.Plugin):
 
         # Run the build.
         build_ref = build_repos[branch_root]['build-ref']
-        order = build_command.compute_build_order(
+        artifact = build_command.get_artifact_object(
             build_branch_root,
             build_ref,
             system_name + '.morph')
-        artifact = order.groups[-1][-1]
 
         if push:
             self.other.delete_remote_build_refs(build_repos)
diff --git a/morphlib/plugins/graphing_plugin.py b/morphlib/plugins/graphing_plugin.py
index c719f6e4..8c4ea2ef 100644
--- a/morphlib/plugins/graphing_plugin.py
+++ b/morphlib/plugins/graphing_plugin.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2012  Codethink Limited
+# Copyright (C) 2012, 2013  Codethink Limited
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -37,7 +37,7 @@ class GraphingPlugin(cliapp.Plugin):
                                 '%(repo_name)s %(ref)s %(filename)s',
                             repo_name=repo_name, ref=ref, filename=filename)
             builder = morphlib.buildcommand.BuildCommand(self.app)
-            order = builder.compute_build_order(repo_name, ref, filename)
+            artifact = builder.get_artifact_object(repo_name, ref, filename)
 
             basename, ext = os.path.splitext(filename)
             dot_filename = basename + '.gv'
@@ -53,17 +53,17 @@ class GraphingPlugin(cliapp.Plugin):
 
             with open(dot_filename, 'w') as f:
                 f.write('digraph "%s" {\n' % basename)
-                for i, group in enumerate(order.groups):
-                    for artifact in group:
-                        f.write(
-                            '  "%s" [shape=%s];\n' %
-                            (artifact.name,
-                             shape_name[artifact.source.morphology['kind']]))
-                        for dep in artifact.dependencies:
-                            if artifact.source.morphology['kind'] == 'stratum':
-                                if dep.dependents == [artifact]:
-                                    f.write(dep_fmt %
-                                            (artifact.name, dep.name))
-                            else:
-                                f.write(dep_fmt % (artifact.name, dep.name))
+                for a in artifact.walk():
+                    f.write(
+                        '  "%s" [shape=%s];\n' %
+                        (a.name,
+                         shape_name[a.source.morphology['kind']]))
+                    for dep in a.dependencies:
+                        if a.source.morphology['kind'] == 'stratum':
+                            if dep.dependents == [a]:
+                                f.write(dep_fmt %
+                                        (a.name, dep.name))
+                        else:
+                            f.write(dep_fmt % (a.name, dep.name))
                 f.write('}\n')
+