persist_data: make SQLTable a context manager

This can be used for more control over the underlying transactions.  Unlike
the context manager of, say, a file object, we can still use the object even
after the end of a given with block, as the context manager exit only ensures
we've committed to the database, not that we have closed the database.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/bb/persist_data.py b/lib/bb/persist_data.py
index aa2ede4b9..af96b76f4 100644
--- a/lib/bb/persist_data.py
+++ b/lib/bb/persist_data.py
@@ -55,6 +55,13 @@ class SQLTable(collections.MutableMapping):
     def _execute(self, *query):
         return self.cursor.execute(*query)
 
+    def __enter__(self):
+        self.cursor.__enter__()
+        return self
+
+    def __exit__(self, *excinfo):
+        self.cursor.__exit__(*excinfo)
+
     def __getitem__(self, key):
         data = self._execute("SELECT * from %s where key=?;" %
                              self.table, [key])