Teach Uploader to ignore files unless they've changed

- specifically we compare the ctime, mtime and size with the
entry in magic-folder db.

diff --git a/src/allmydata/frontends/magic_folder.py b/src/allmydata/frontends/magic_folder.py
index 1ca638e874682d0c8d751f81420091e8fa9bafd2..11590d569fc5a77204938168e55699c70473005c 100644 (file)
--- a/src/allmydata/frontends/magic_folder.py
+++ b/src/allmydata/frontends/magic_folder.py
@@ -336,6 +336,8 @@ class Uploader(QueueMixin):
                     version = 0
                 elif self._db.is_new_file_time(abspath_u, relpath_u):
                     version += 1
+                else:
+                    return None
 
                 uploadable = FileName(abspath_u, self._client.convergence)
                 d2 = self._upload_dirnode.add_file(encoded_name_u, uploadable, metadata={"version":version}, overwrite=True)