_scheduler/scheduler.py: Adhere to policy on private symbols

Also added Scheduler.jobs_suspended() context manager to
use in the App instead of exposing Scheduler.suspend_jobs()
and Scheduler.resume_jobs() along with signal callback connect
and disconnect APIs, this keeps things more private in the
scheduler.

This is a part of issue #285

1 files changed, 5 insertions, 9 deletions

diff --git a/buildstream/_frontend/app.py b/buildstream/_frontend/app.py
index db9c97b84..f4336956d 100644
--- a/buildstream/_frontend/app.py
+++ b/buildstream/_frontend/app.py
@@ -778,16 +778,12 @@ class App():
 
     @contextmanager
     def _interrupted(self):
-        self.scheduler.disconnect_signals()
-
         self._status.clear()
-        self.scheduler.suspend_jobs()
-
-        yield
-
-        self._maybe_render_status()
-        self.scheduler.resume_jobs()
-        self.scheduler.connect_signals()
+        try:
+            with self.scheduler.jobs_suspended():
+                yield
+        finally:
+            self._maybe_render_status()
 
     # Some validation routines for project initialization
     #