+class DatabaseCache:
+ def __init__(self):
+ try:
+ from notmuch2 import Database
+ self._notmuch = Database()
+ except ImportError:
+ self._notmuch = None
+ self._known = {}
+
+ def known(self,id):
+ if id in self._known:
+ return self._known[id];
+
+ if self._notmuch:
+ try:
+ _ = self._notmuch.find(id)
+ self._known[id] = True
+ except LookupError:
+ self._known[id] = False
+ else:
+ (_, stdout, stderr) = _spawn(
+ args=['notmuch', 'search', '--output=files', 'id:{0}'.format(id)],
+ stdout=_subprocess.PIPE,
+ wait=True)
+ self._known[id] = stdout != None
+ return self._known[id]