| //! Closure type (equivalent to `&mut dyn FnMut(A) -> R`) that's `repr(C)`. |
| |
| use std::marker::PhantomData; |
| |
| #[repr(C)] |
| pub struct Closure<'a, A, R> { |
| call: unsafe extern "C" fn(*mut Env, A) -> R, |
| env: *mut Env, |
| // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual way of doing |
| // this, but that requires unstable features. rust-analyzer uses this code |
| // and avoids unstable features. |
| // |
| // The `'a` lifetime parameter represents the lifetime of `Env`. |
| _marker: PhantomData<*mut &'a mut ()>, |
| } |
| |
| struct Env; |
| |
| impl<'a, A, R, F: FnMut(A) -> R> From<&'a mut F> for Closure<'a, A, R> { |
| fn from(f: &'a mut F) -> Self { |
| unsafe extern "C" fn call<A, R, F: FnMut(A) -> R>(env: *mut Env, arg: A) -> R { |
| (*(env as *mut _ as *mut F))(arg) |
| } |
| Closure { call: call::<A, R, F>, env: f as *mut _ as *mut Env, _marker: PhantomData } |
| } |
| } |
| |
| impl<'a, A, R> Closure<'a, A, R> { |
| pub fn call(&mut self, arg: A) -> R { |
| unsafe { (self.call)(self.env, arg) } |
| } |
| } |