comparison rust/hg-cpython/src/ref_sharing.rs @ 43174:1c675c5fe5fe

rust-cpython: move borrow_mut() to PySharedRefCell

PySharedRefCell() will host almost all py_shared public functions. This change
is the first step.

borrow_mut() can be safely implemented since PySharedRefCell knows its inner
object is managed by its own py_shared_state.

43173:070a38737334

    pub fn as_ptr(&self) -> *mut T {
        self.inner.as_ptr()
    }

    pub unsafe fn borrow_mut(&self) -> RefMut<T> {
        // must be borrowed by self.py_shared_state(py).borrow_mut().
        self.inner.borrow_mut()
    }
}

/// Holds a mutable reference to data shared between Python and Rust.
pub struct PyRefMut<'a, T> {

        $inner_struct: ident,
        $data_member: ident,
        $leaked: ident,
    ) => {
        impl $name {
            fn borrow_mut<'a>(
                &'a self,
                py: Python<'a>,
            ) -> PyResult<crate::ref_sharing::PyRefMut<'a, $inner_struct>>
            {
                // assert $data_member type
                use crate::ref_sharing::PySharedRefCell;
                let data: &PySharedRefCell<_> = self.$data_member(py);
                data.py_shared_state
                    .borrow_mut(py, unsafe { data.borrow_mut() })
            }

            /// Returns a leaked reference and its management object.
            ///
            /// # Safety

43174:1c675c5fe5fe

    pub fn as_ptr(&self) -> *mut T {
        self.inner.as_ptr()
    }

    // TODO: maybe this should be named as try_borrow_mut(), and use
    // inner.try_borrow_mut(). The current implementation panics if
    // self.inner has been borrowed, but returns error if py_shared_state
    // refuses to borrow.
    pub fn borrow_mut<'a>(
        &'a self,
        py: Python<'a>,
    ) -> PyResult<PyRefMut<'a, T>> {
        self.py_shared_state.borrow_mut(py, self.inner.borrow_mut())
    }
}

/// Holds a mutable reference to data shared between Python and Rust.
pub struct PyRefMut<'a, T> {

        $inner_struct: ident,
        $data_member: ident,
        $leaked: ident,
    ) => {
        impl $name {
            // TODO: remove this function in favor of inner(py).borrow_mut()
            fn borrow_mut<'a>(
                &'a self,
                py: Python<'a>,
            ) -> PyResult<crate::ref_sharing::PyRefMut<'a, $inner_struct>>
            {
                // assert $data_member type
                use crate::ref_sharing::PySharedRefCell;
                let data: &PySharedRefCell<_> = self.$data_member(py);
                data.borrow_mut(py)
            }

            /// Returns a leaked reference and its management object.
            ///
            /// # Safety