Method with_store

crates/debugger/src/lib.rs:442–497

Perform some action on the contained `Store` while not running. This may only be invoked before the inner body finishes and when it is paused; that is, when the `Debuggee` is initially created and after any call to `run()` returns a result other than `DebugRunResult::Finished`. If an earlier `run()` invocation was canceled, it must be re-invoked and return successfully before a query is made. Th

(
        &mut self,
        f: F,
    )

    /// This is cancel-safe; if canceled, the result of the query will
    /// be dropped.
    pub async fn with_store<
        F: FnOnce(StoreContextMut<'_, T>) -> R + Send + 'static,
        R: Send + 'static,
    >(
        &mut self,
        f: F,
    ) -> Result<R> {
        if let Some(store) = self.store.as_mut() {
            return Ok(f(store.as_context_mut()));
        }

        self.wait_for_initial().await?;

        match self.state {
            DebuggeeState::Initial => unreachable!(),
            DebuggeeState::Queried => {
                // Earlier query canceled; drop its response first.
                let response =
                    self.out_rx.recv().await.ok_or_else(|| {
                        wasmtime::format_err!("Premature close of debugger channel")
                    })?;
                assert!(matches!(response, Response::QueryResponse(_)));
                self.state = DebuggeeState::Paused;
            }
            DebuggeeState::Running => {
                // Results from a canceled `run()`; `run()` must
                // complete before this can be invoked.
                panic!("Cannot query in Running state");
            }
            DebuggeeState::Complete => {
                panic!("Cannot query when complete");
            }
            DebuggeeState::Paused => {
                // OK -- this is the state we want.
            }
        }

        log::trace!("sending query in with_store");
        self.in_tx
            .send(Command::Query(Box::new(|store| Box::new(f(store)))))
            .await
            .map_err(|_| wasmtime::format_err!("Premature close of debugger channel"))?;
        self.state = DebuggeeState::Queried;

        let response = self
            .out_rx
            .recv()
            .await
            .ok_or_else(|| wasmtime::format_err!("Premature close of debugger channel"))?;
        let Response::QueryResponse(resp) = response else {
            wasmtime::bail!("Incorrect response from debugger task");
        };
        self.state = DebuggeeState::Paused;

        Ok(*resp.downcast::<R>().expect("type mismatch"))
    }
}