Struct cpython::PySharedRefCell [−][src]
A mutable memory location shareable immutably across Python objects.
This is a RefCell that can also be borrowed immutably by another Python object.
The primary use case is to implement a Python iterator over a Rust
iterator. Since a Python object cannot hold a lifetime-bound object,
Iter<'a, T>
cannot be a data field of the Python iterator object.
PySharedRef::leak_immutable() provides a way around this issue.
py_class!(pub class List |py| { @shared data rust_vec: Vec<i32>; def __iter__(&self) -> PyResult<ListIterator> { let leaked = self.rust_vec(py).leak_immutable(); ListIterator::create_instance( py, RefCell::new(unsafe { leaked.map(py, |o| o.iter()) }), ) } }); py_class!(pub class ListIterator |py| { data rust_iter: RefCell<UnsafePyLeaked<Iter<'static, i32>>>; def __next__(&self) -> PyResult<Option<PyInt>> { let mut leaked = self.rust_iter(py).borrow_mut(); let mut iter = unsafe { leaked.try_borrow_mut(py)? }; Ok(iter.next().map(|v| v.to_py_object(py))) } def __iter__(&self) -> PyResult<Self> { Ok(self.clone_ref(py)) } });
The borrow rules are enforced dynamically in a similar manner to the Python iterator.
PySharedRefCell
is merely a data struct to be stored in a Python object.
Any further operation will be performed through PySharedRef, which is
a lifetime-bound reference to the PySharedRefCell
.
Implementations
impl<T> PySharedRefCell<T>
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pub fn new(value: T) -> PySharedRefCell<T>
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Creates a new PySharedRefCell
containing value
.
Trait Implementations
impl<T: Debug + ?Sized> Debug for PySharedRefCell<T>
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Auto Trait Implementations
impl<T> !RefUnwindSafe for PySharedRefCell<T>
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impl<T: ?Sized> Send for PySharedRefCell<T> where
T: Send,
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T: Send,
impl<T> !Sync for PySharedRefCell<T>
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impl<T: ?Sized> Unpin for PySharedRefCell<T> where
T: Unpin,
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T: Unpin,
impl<T: ?Sized> UnwindSafe for PySharedRefCell<T> where
T: UnwindSafe,
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T: UnwindSafe,
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,