Method join

crates/wasmtime/src/runtime/component/concurrent.rs:4820–4848

Move this `Waitable` to the specified set (when `set` is `Some(_)`) or remove it from any set it may currently belong to (when `set` is `None`).

(&self, state: &mut ConcurrentState, set: Option<TableId<WaitableSet>>)

    /// remove it from any set it may currently belong to (when `set` is
    /// `None`).
    fn join(&self, state: &mut ConcurrentState, set: Option<TableId<WaitableSet>>) -> Result<()> {
        log::trace!("waitable {self:?} join set {set:?}");

        let old = mem::replace(&mut self.common(state)?.set, set);

        if let Some(old) = old {
            match *self {
                Waitable::Host(id) => state.remove_child(id, old),
                Waitable::Guest(id) => state.remove_child(id, old),
                Waitable::Transmit(id) => state.remove_child(id, old),
            }?;

            state.get_mut(old)?.ready.remove(self);
        }

        if let Some(set) = set {
            match *self {
                Waitable::Host(id) => state.add_child(id, set),
                Waitable::Guest(id) => state.add_child(id, set),
                Waitable::Transmit(id) => state.add_child(id, set),
            }?;

            if self.common(state)?.event.is_some() {
                self.mark_ready(state)?;
            }
        }

        Ok(())
    }

    /// Retrieve mutable access to the `WaitableCommon` for this `Waitable`.
    fn common<'a>(&self, state: &'a mut ConcurrentState) -> Result<&'a mut WaitableCommon> {