Trait HotFunction 

pub trait HotFunction<Args, Marker> {
    type Return;
    type Real;

    // Required methods
    fn call_it(&mut self, args: Args) -> Self::Return;
    unsafe fn call_as_ptr(&mut self, _args: Args) -> Self::Return;
}

A trait that enables types to be hot-patched.

This trait is only implemented for FnMut types which naturally includes function pointers and closures that can be re-ran. FnOnce closures are currently not supported since the hot-patching system we use implies that the function can be called multiple times.

Required Associated Types

type Return

The return type of the function.

type Real

The real function type. This is meant to be a function pointer. When we call call_as_ptr, we will transmute the function to this type and call it.

Required Methods

fn call_it(&mut self, args: Args) -> Self::Return

Call the HotFunction with the given arguments.

Why

“rust-call” isn’t stable, so we wrap the underlying call with our own, giving it a stable vtable entry. This is more important than it seems since this function becomes “real” and can be hot-patched.

unsafe fn call_as_ptr(&mut self, _args: Args) -> Self::Return

Call the HotFunction as if it were a function pointer.

Safety

This is only safe if the underlying type is a function (function pointer or virtual/fat pointer). Using this will use the JumpTable to find the patched function and call it.

Implementors