How to move a value out of tokio RwLock/Mutex

[ActivePeter]

I'm using protobuf and it need the vec to construct bytes, but the vec is in RwLock and cannot be moved. Is there any way to move the data without cloning the vec?

[hawkw]

Try using std::mem::take;

use tokio::sync::RwLock;
use std::mem;

let rwlock = RwLock::new(Vec::new());

// ...

// use `mem::take` to move the `Vec` out of the `RwLock`.
let mut write = lock.write().await;
let the_vec = mem::take(&mut *write);

// now, we have the `Vec` and can pass it into whatever function we need
do_something_with_the_vec(the_vec);

take will move the Vec out of the RwLock, replacing it with the value of Vec::default (an empty vector), and return it. The RwLock will then contain a new empty Vec, which you can use again.

Alternatively, if you want to replace the value inside the RwLock with something other than Vec::default, you can use std::mem::replace instead. This functions similarly to mem::take, but it allows you to provide a replacement value.

[ActivePeter]

Thank you so much.

[Darksonn]

For cases where you have ownership of the lock, you can call the into_inner method which consumes the lock and returns the contents.