db/utils: move is_subdir_of() to the single place it is used in

1 files changed, 9 insertions, 2 deletions

diff --git a/alot/db/manager.py b/alot/db/manager.py
index 4d1bb5b2..888e9404 100644
--- a/alot/db/manager.py
+++ b/alot/db/manager.py
@@ -18,9 +18,16 @@ from .errors import DatabaseLockedError
 from .errors import DatabaseROError
 from .errors import NonexistantObjectError
 from .thread import Thread
-from .utils import is_subdir_of
 from ..settings.const import settings
 
+def _is_subdir_of(subpath, superpath):
+    # make both absolute
+    superpath = os.path.realpath(superpath)
+    subpath = os.path.realpath(subpath)
+
+    # return true, if the common prefix of both is equal to directory
+    # e.g. /a/b/c/d.rst and directory is /a/b, the common prefix is /a/b
+    return os.path.commonprefix([subpath, superpath]) == superpath
 
 class FillPipeProcess(multiprocessing.Process):
 
@@ -415,7 +422,7 @@ class DBManager:
 
         if self.ro:
             raise DatabaseROError()
-        if not is_subdir_of(path, self.path):
+        if not _is_subdir_of(path, self.path):
             msg = 'message path %s ' % path
             msg += ' is not below notmuchs '
             msg += 'root path (%s)' % self.path