comparison rust/hg-cpython/src/ref_sharing.rs @ 43175:a1908eb08342

rust-cpython: mark PySharedState as Sync so &'PySharedState can be Send

The goal is to store &'static PySharedState in $leaked struct, which allows
us to move the $leaked struct out of the macro. Currently, it depends on
inner.$data_member(py), which can't be generalized.

PySharedState is Sync because any mutation or read operation is synchronized
by the Python GIL, py: Python<'a>, which should guarantee that &'PySharedState
can be sent to another thread.

43174:1c675c5fe5fe

pub struct PySharedState {
    leak_count: Cell<usize>,
    mutably_borrowed: Cell<bool>,
}

impl PySharedState {
    pub fn borrow_mut<'a, T>(
        &'a self,
        py: Python<'a>,
        pyrefmut: RefMut<'a, T>,

43175:a1908eb08342

pub struct PySharedState {
    leak_count: Cell<usize>,
    mutably_borrowed: Cell<bool>,
}

// &PySharedState can be Send because any access to inner cells is
// synchronized by the GIL.
unsafe impl Sync for PySharedState {}

impl PySharedState {
    pub fn borrow_mut<'a, T>(
        &'a self,
        py: Python<'a>,
        pyrefmut: RefMut<'a, T>,