Struct ErasedWeakFn 

pub struct ErasedWeakFn<VTable: VTableMetaDropInPlace + 'static, Ret, Arg: ?Sized = ()> { /* private fields */ }

Runs a stored function on a mapped object as long as that object is still alive.

Create one from a VRcMapped and a function with VRcMapped::downgrade_erased_fn, then call Self::upgrade_and_call whenever you want to run the function on the object, passing the argument it expects (&() if it takes none). Once every strong reference to the object is gone, upgrade_and_call returns None and the function is not run.

The type is only parameterized by the argument and return types, not by the type of the mapped object, so code that stores an ErasedWeakFn is compiled once no matter how many mapped types it is used with.

Implementations

impl<VTable: VTableMetaDropInPlace + 'static, Ret, Arg: ?Sized> ErasedWeakFn<VTable, Ret, Arg>

pub fn upgrade_and_call(&self, arg: &Arg) -> Option<Ret>

Run the stored function on the object with arg, or return None if the object has been dropped.