proc_macro/bridge/
closure.rs

1//! Closure type (equivalent to `&mut dyn FnMut(Buffer) -> Buffer`) that's `repr(C)`.
2
3use std::marker::PhantomData;
4
5use super::Buffer;
6
7#[repr(C)]
8pub(super) struct Closure<'a> {
9    call: extern "C" fn(*mut Env, Buffer) -> Buffer,
10    env: *mut Env,
11    // Prevent Send and Sync impls.
12    //
13    // The `'a` lifetime parameter represents the lifetime of `Env`.
14    _marker: PhantomData<*mut &'a mut ()>,
15}
16
17struct Env;
18
19impl<'a, F: FnMut(Buffer) -> Buffer> From<&'a mut F> for Closure<'a> {
20    fn from(f: &'a mut F) -> Self {
21        extern "C" fn call<F: FnMut(Buffer) -> Buffer>(env: *mut Env, arg: Buffer) -> Buffer {
22            unsafe { (*(env as *mut _ as *mut F))(arg) }
23        }
24        Closure { call: call::<F>, env: f as *mut _ as *mut Env, _marker: PhantomData }
25    }
26}
27
28impl<'a> Closure<'a> {
29    pub(super) fn call(&mut self, arg: Buffer) -> Buffer {
30        (self.call)(self.env, arg)
31    }
32}
proc_macro/bridge/closure.rs

proc_macro/bridge/
closure.rs
