Struct MultiUseContextCallback

pub struct MultiUseContextCallback<'func, Cur: Sandbox, F>
where
    F: FnOnce(&mut MultiUseGuestCallContext) -> Result<()> + 'func,
{ /* private fields */ }

A TransitionMetadata that calls a callback. The callback function takes a mutable reference to a MultiUseGuestCallContext and returns a Result<()> to signify success or failure of the function.

The function use the context to call guest functions.

Construct one of these by passing your callback to MultiUseContextCallback::from, as in the following code (assuming MySandbox is a Sandbox implementation):

let my_cb_fn: dyn FnOnce(&mut MultiUseGuestCallContext) -> Result<()> = |_sbox| {
    println!("hello world!");
};
let mutating_cb = MultiUseContextCallback::from(my_cb_fn);

Implementations

impl<Cur: Sandbox, F> MultiUseContextCallback<'_, Cur, F>

where F: FnOnce(&mut MultiUseGuestCallContext) -> Result<()>,

pub fn call(self, cur: &mut MultiUseGuestCallContext) -> Result<()>

Invokes the callback on the provided guest context

Trait Implementations

impl<'a, F> EvolvableSandbox<MultiUseSandbox, MultiUseSandbox, MultiUseContextCallback<'a, MultiUseSandbox, F>> for MultiUseSandbox

where F: FnOnce(&mut MultiUseGuestCallContext) -> Result<()> + 'a,

fn evolve( self, transition_func: MultiUseContextCallback<'a, MultiUseSandbox, F>, ) -> Result<MultiUseSandbox>

The purpose of this function is to allow multiple states to be associated with a single MultiUseSandbox.

An implementation such as HyperlightJs or HyperlightWasm can use this to call guest functions to load JS or WASM code and then evolve the sandbox causing state to be captured. The new MultiUseSandbox can then be used to call guest functions to execute the loaded code.

The evolve function creates a new MultiUseCallContext which is then passed to a callback function allowing the callback function to call guest functions as part of the evolve process, once the callback function is complete the context is finished using a crate internal method that does not restore the prior state of the Sandbox. It then creates a mew memory snapshot on the snapshot stack and returns the MultiUseSandbox

impl<'a, Cur: Sandbox, F> From<F> for MultiUseContextCallback<'a, Cur, F>

where F: FnOnce(&mut MultiUseGuestCallContext) -> Result<()> + 'a,

fn from(val: F) -> Self

Converts to this type from the input type.

impl<Cur: Sandbox, Next: Sandbox, F> TransitionMetadata<Cur, Next> for MultiUseContextCallback<'_, Cur, F>

where F: FnOnce(&mut MultiUseGuestCallContext) -> Result<()>,