The previous implementation had some slightly questionable memory safety
properties (older versions of PyO3 didn't uphold the Rust aliasing rules
and would thus create multiple &mut references to #[pyclass] objects).
This explains why Backend has internal Mutex<T>s even though all of its
methods took &mut self.
The solution is to simply make all methods take &self, which luckily
doesn't pose too make issues -- most of the code inside Backend already
has sufficient locking. The only two things which needed to be
explicitly handled where:
1. "self.runtime" which was fairly easy to handle. All usages of
the Runtime only require an immutable reference to create a new
Handle, so we could switch to OnceCell which provides
lazy-initialisation semantics without needing a more heavy-handed
Mutex<tokio::runtime::Handle>.
2. "self.sync_abort" was simply wrapped in a Mutex<>, though some of the
odd semantics of sync_abort (not being able to handle multiple
processes synchronising at the same time) become pretty obvious with
this change (for now we just log a warning in that case). In
addition, switch to an RAII-style guard to make sure we don't forget
to clear the abort_handle.
As a result, we now no longer break Rust's aliasing rules and we can
build with newer versions of PyO3 which have runtime checks for these
things (and build on stable Rust).
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
This reverts commit cf247baf77.
The separate read and write timeouts were causing syncs to fail - a
long full upload would time out due to no read activity for example.
Reverting until a better fix can be put in place.
This reverts commit abe90d0772.
trust-dns has introduced its own issues, such as when resolv.conf is
inaccessible, or contains hostnames with certain characters
- tag list stored in a separate DB table
- non-wildcard searches now do full unicode case folding
(eg tag:masse matches 'Maße')
- wildcard matches do simple unicode case folding
- some functions haven't been updated yet, so ascii folding will
continue to be used in some operations
The progress handling code needs a rethink, as we now have two separate
ways to flag that the media sync should abort. In the future, it may
make sense to switch to polling the backend for progress, instead of
passing a callback in.
