Add PyCell::borrow shortcuts to Py

This commit is contained in:
David Hewitt 2020-06-14 22:36:07 +01:00
parent a524699301
commit 925986c706
4 changed files with 69 additions and 10 deletions

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@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
### Added ### Added
- Add FFI definition `PyObject_AsFileDescriptor` [#938](https://github.com/PyO3/pyo3/pull/938) - Add FFI definition `PyObject_AsFileDescriptor` [#938](https://github.com/PyO3/pyo3/pull/938)
- Add `PyByteArray::data`, `PyByteArray::as_bytes`, and `PyByteArray::as_bytes_mut`. [#967](https://github.com/PyO3/pyo3/pull/967) - Add `PyByteArray::data`, `PyByteArray::as_bytes`, and `PyByteArray::as_bytes_mut`. [#967](https://github.com/PyO3/pyo3/pull/967)
- Add `Py::borrow`, `Py::borrow_mut`, `Py::try_borrow`, and `Py::try_borrow_mut` for accessing `#[pyclass]` values. [#976](https://github.com/PyO3/pyo3/pull/976)
### Changed ### Changed
- Simplify internals of `#[pyo3(get)]` attribute. (Remove the hidden API `GetPropertyValue`.) [#934](https://github.com/PyO3/pyo3/pull/934) - Simplify internals of `#[pyo3(get)]` attribute. (Remove the hidden API `GetPropertyValue`.) [#934](https://github.com/PyO3/pyo3/pull/934)

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@ -2,10 +2,11 @@
use crate::err::{PyErr, PyResult}; use crate::err::{PyErr, PyResult};
use crate::gil; use crate::gil;
use crate::object::PyObject; use crate::object::PyObject;
use crate::pycell::{PyBorrowError, PyBorrowMutError, PyCell};
use crate::type_object::PyBorrowFlagLayout; use crate::type_object::PyBorrowFlagLayout;
use crate::{ use crate::{
ffi, AsPyPointer, FromPyObject, IntoPy, IntoPyPointer, PyAny, PyCell, PyClass, ffi, AsPyPointer, FromPyObject, IntoPy, IntoPyPointer, PyAny, PyClass, PyClassInitializer,
PyClassInitializer, PyRef, PyRefMut, PyTypeInfo, Python, ToPyObject, PyRef, PyRefMut, PyTypeInfo, Python, ToPyObject,
}; };
use std::marker::PhantomData; use std::marker::PhantomData;
use std::mem; use std::mem;
@ -49,14 +50,13 @@ unsafe impl<T> Send for Py<T> {}
unsafe impl<T> Sync for Py<T> {} unsafe impl<T> Sync for Py<T> {}
impl<T> Py<T> { impl<T> Py<T>
/// Create a new instance `Py<T>`. where
/// T: PyClass,
/// You can crate [`PyCell::new`](../pycell/struct.PyCell.html#method.new) and `Py::from`, {
/// but this method can be more efficient. /// Create a new instance `Py<T>` of a `#[pyclass]` on the Python heap.
pub fn new(py: Python, value: impl Into<PyClassInitializer<T>>) -> PyResult<Py<T>> pub fn new(py: Python, value: impl Into<PyClassInitializer<T>>) -> PyResult<Py<T>>
where where
T: PyClass,
T::BaseLayout: PyBorrowFlagLayout<T::BaseType>, T::BaseLayout: PyBorrowFlagLayout<T::BaseType>,
{ {
let initializer = value.into(); let initializer = value.into();
@ -65,6 +65,57 @@ impl<T> Py<T> {
Ok(ob) Ok(ob)
} }
/// Immutably borrows the value `T`. This borrow lasts untill the returned `PyRef` exists.
///
/// Equivalent to `self.as_ref(py).borrow()` -
/// see [`PyCell::borrow`](../pycell/struct.PyCell.html#method.borrow)
///
/// # Panics
/// Panics if the value is currently mutably borrowed. For a non-panicking variant, use
/// [`try_borrow`](#method.try_borrow).
pub fn borrow<'py>(&'py self, py: Python<'py>) -> PyRef<'py, T> {
self.as_ref(py).borrow()
}
/// Mutably borrows the value `T`. This borrow lasts untill the returned `PyRefMut` exists.
///
/// Equivalent to `self.as_ref(py).borrow_mut()` -
/// see [`PyCell::borrow_mut`](../pycell/struct.PyCell.html#method.borrow_mut)
///
/// # Panics
/// Panics if the value is currently mutably borrowed. For a non-panicking variant, use
/// [`try_borrow_mut`](#method.try_borrow_mut).
pub fn borrow_mut<'py>(&'py self, py: Python<'py>) -> PyRefMut<'py, T> {
self.as_ref(py).borrow_mut()
}
/// Immutably borrows the value `T`, returning an error if the value is currently
/// mutably borrowed. This borrow lasts untill the returned `PyRef` exists.
///
/// This is the non-panicking variant of [`borrow`](#method.borrow).
///
/// Equivalent to `self.as_ref(py).try_borrow()` -
/// see [`PyCell::try_borrow`](../pycell/struct.PyCell.html#method.try_borrow)
pub fn try_borrow<'py>(&'py self, py: Python<'py>) -> Result<PyRef<'py, T>, PyBorrowError> {
self.as_ref(py).try_borrow()
}
/// Mutably borrows the value `T`, returning an error if the value is currently borrowed.
/// This borrow lasts untill the returned `PyRefMut` exists.
///
/// This is the non-panicking variant of [`borrow_mut`](#method.borrow_mut).
///
/// Equivalent to `self.as_ref(py).try_borrow_mut() -
/// see [`PyCell::try_borrow_mut`](../pycell/struct.PyCell.html#method.try_borrow_mut)
pub fn try_borrow_mut<'py>(
&'py self,
py: Python<'py>,
) -> Result<PyRefMut<'py, T>, PyBorrowMutError> {
self.as_ref(py).try_borrow_mut()
}
}
impl<T> Py<T> {
/// Creates a `Py<T>` instance for the given FFI pointer. /// Creates a `Py<T>` instance for the given FFI pointer.
/// ///
/// This moves ownership over the pointer into the `Py<T>`. /// This moves ownership over the pointer into the `Py<T>`.

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@ -166,8 +166,11 @@ pub struct PyCell<T: PyClass> {
unsafe impl<T: PyClass> PyNativeType for PyCell<T> {} unsafe impl<T: PyClass> PyNativeType for PyCell<T> {}
impl<T: PyClass> PyCell<T> { impl<T: PyClass> PyCell<T> {
/// Make new `PyCell` on the Python heap and returns the reference of it. /// Make a new `PyCell` on the Python heap and return the reference to it.
/// ///
/// In cases where the value in the cell does not need to be accessed immediately after
/// creation, consider [`Py::new`](../instance/struct.Py.html#method.new) as a more efficient
/// alternative.
pub fn new(py: Python, value: impl Into<PyClassInitializer<T>>) -> PyResult<&Self> pub fn new(py: Python, value: impl Into<PyClassInitializer<T>>) -> PyResult<&Self>
where where
T::BaseLayout: PyBorrowFlagLayout<T::BaseType>, T::BaseLayout: PyBorrowFlagLayout<T::BaseType>,

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@ -73,7 +73,11 @@ pub unsafe fn tp_free_fallback(obj: *mut ffi::PyObject) {
/// The `#[pyclass]` attribute automatically implements this trait for your Rust struct, /// The `#[pyclass]` attribute automatically implements this trait for your Rust struct,
/// so you don't have to use this trait directly. /// so you don't have to use this trait directly.
pub trait PyClass: pub trait PyClass:
PyTypeInfo<Layout = PyCell<Self>> + Sized + PyClassAlloc + PyMethods + Send PyTypeInfo<Layout = PyCell<Self>, AsRefTarget = PyCell<Self>>
+ Sized
+ PyClassAlloc
+ PyMethods
+ Send
{ {
/// Specify this class has `#[pyclass(dict)]` or not. /// Specify this class has `#[pyclass(dict)]` or not.
type Dict: PyClassDict; type Dict: PyClassDict;