pyo3/pyclass.rs
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//! `PyClass` and related traits.
use crate::{
callback::IntoPyCallbackOutput, ffi, impl_::pyclass::PyClassImpl, IntoPy, PyObject, PyResult,
PyTypeInfo, Python,
};
use std::{cmp::Ordering, os::raw::c_int};
mod create_type_object;
mod gc;
pub(crate) use self::create_type_object::{create_type_object, PyClassTypeObject};
pub use self::gc::{PyTraverseError, PyVisit};
/// Types that can be used as Python classes.
///
/// The `#[pyclass]` attribute implements this trait for your Rust struct -
/// you shouldn't implement this trait directly.
#[allow(deprecated)]
#[cfg(feature = "gil-refs")]
pub trait PyClass: PyTypeInfo<AsRefTarget = crate::PyCell<Self>> + PyClassImpl {
/// Whether the pyclass is frozen.
///
/// This can be enabled via `#[pyclass(frozen)]`.
type Frozen: Frozen;
}
/// Types that can be used as Python classes.
///
/// The `#[pyclass]` attribute implements this trait for your Rust struct -
/// you shouldn't implement this trait directly.
#[cfg(not(feature = "gil-refs"))]
pub trait PyClass: PyTypeInfo + PyClassImpl {
/// Whether the pyclass is frozen.
///
/// This can be enabled via `#[pyclass(frozen)]`.
type Frozen: Frozen;
}
/// Operators for the `__richcmp__` method
#[derive(Debug, Clone, Copy)]
pub enum CompareOp {
/// The *less than* operator.
Lt = ffi::Py_LT as isize,
/// The *less than or equal to* operator.
Le = ffi::Py_LE as isize,
/// The equality operator.
Eq = ffi::Py_EQ as isize,
/// The *not equal to* operator.
Ne = ffi::Py_NE as isize,
/// The *greater than* operator.
Gt = ffi::Py_GT as isize,
/// The *greater than or equal to* operator.
Ge = ffi::Py_GE as isize,
}
impl CompareOp {
/// Conversion from the C enum.
pub fn from_raw(op: c_int) -> Option<Self> {
match op {
ffi::Py_LT => Some(CompareOp::Lt),
ffi::Py_LE => Some(CompareOp::Le),
ffi::Py_EQ => Some(CompareOp::Eq),
ffi::Py_NE => Some(CompareOp::Ne),
ffi::Py_GT => Some(CompareOp::Gt),
ffi::Py_GE => Some(CompareOp::Ge),
_ => None,
}
}
/// Returns if a Rust [`std::cmp::Ordering`] matches this ordering query.
///
/// Usage example:
///
/// ```rust
/// # use pyo3::prelude::*;
/// # use pyo3::class::basic::CompareOp;
///
/// #[pyclass]
/// struct Size {
/// size: usize,
/// }
///
/// #[pymethods]
/// impl Size {
/// fn __richcmp__(&self, other: &Size, op: CompareOp) -> bool {
/// op.matches(self.size.cmp(&other.size))
/// }
/// }
/// ```
pub fn matches(&self, result: Ordering) -> bool {
match self {
CompareOp::Eq => result == Ordering::Equal,
CompareOp::Ne => result != Ordering::Equal,
CompareOp::Lt => result == Ordering::Less,
CompareOp::Le => result != Ordering::Greater,
CompareOp::Gt => result == Ordering::Greater,
CompareOp::Ge => result != Ordering::Less,
}
}
}
/// Output of `__next__` which can either `yield` the next value in the iteration, or
/// `return` a value to raise `StopIteration` in Python.
///
/// Usage example:
///
/// ```rust
/// # #![allow(deprecated)]
/// use pyo3::prelude::*;
/// use pyo3::iter::IterNextOutput;
///
/// #[pyclass]
/// struct PyClassIter {
/// count: usize,
/// }
///
/// #[pymethods]
/// impl PyClassIter {
/// #[new]
/// pub fn new() -> Self {
/// PyClassIter { count: 0 }
/// }
///
/// fn __next__(&mut self) -> IterNextOutput<usize, &'static str> {
/// if self.count < 5 {
/// self.count += 1;
/// // Given an instance `counter`, First five `next(counter)` calls yield 1, 2, 3, 4, 5.
/// IterNextOutput::Yield(self.count)
/// } else {
/// // At the sixth time, we get a `StopIteration` with `'Ended'`.
/// // try:
/// // next(counter)
/// // except StopIteration as e:
/// // assert e.value == 'Ended'
/// IterNextOutput::Return("Ended")
/// }
/// }
/// }
/// ```
#[deprecated(since = "0.21.0", note = "Use `Option` or `PyStopIteration` instead.")]
pub enum IterNextOutput<T, U> {
/// The value yielded by the iterator.
Yield(T),
/// The `StopIteration` object.
Return(U),
}
/// Alias of `IterNextOutput` with `PyObject` yield & return values.
#[deprecated(since = "0.21.0", note = "Use `Option` or `PyStopIteration` instead.")]
#[allow(deprecated)]
pub type PyIterNextOutput = IterNextOutput<PyObject, PyObject>;
#[allow(deprecated)]
impl<T, U> IntoPyCallbackOutput<*mut ffi::PyObject> for IterNextOutput<T, U>
where
T: IntoPy<PyObject>,
U: IntoPy<PyObject>,
{
fn convert(self, py: Python<'_>) -> PyResult<*mut ffi::PyObject> {
match self {
IterNextOutput::Yield(o) => Ok(o.into_py(py).into_ptr()),
IterNextOutput::Return(o) => {
Err(crate::exceptions::PyStopIteration::new_err(o.into_py(py)))
}
}
}
}
/// Output of `__anext__`.
///
/// <https://docs.python.org/3/reference/expressions.html#agen.__anext__>
#[deprecated(
since = "0.21.0",
note = "Use `Option` or `PyStopAsyncIteration` instead."
)]
pub enum IterANextOutput<T, U> {
/// An expression which the generator yielded.
Yield(T),
/// A `StopAsyncIteration` object.
Return(U),
}
/// An [IterANextOutput] of Python objects.
#[deprecated(
since = "0.21.0",
note = "Use `Option` or `PyStopAsyncIteration` instead."
)]
#[allow(deprecated)]
pub type PyIterANextOutput = IterANextOutput<PyObject, PyObject>;
#[allow(deprecated)]
impl<T, U> IntoPyCallbackOutput<*mut ffi::PyObject> for IterANextOutput<T, U>
where
T: IntoPy<PyObject>,
U: IntoPy<PyObject>,
{
fn convert(self, py: Python<'_>) -> PyResult<*mut ffi::PyObject> {
match self {
IterANextOutput::Yield(o) => Ok(o.into_py(py).into_ptr()),
IterANextOutput::Return(o) => Err(crate::exceptions::PyStopAsyncIteration::new_err(
o.into_py(py),
)),
}
}
}
/// A workaround for [associated const equality](https://github.com/rust-lang/rust/issues/92827).
///
/// This serves to have True / False values in the [`PyClass`] trait's `Frozen` type.
#[doc(hidden)]
pub mod boolean_struct {
pub(crate) mod private {
use super::*;
/// A way to "seal" the boolean traits.
pub trait Boolean {
const VALUE: bool;
}
impl Boolean for True {
const VALUE: bool = true;
}
impl Boolean for False {
const VALUE: bool = false;
}
}
pub struct True(());
pub struct False(());
}
/// A trait which is used to describe whether a `#[pyclass]` is frozen.
#[doc(hidden)]
pub trait Frozen: boolean_struct::private::Boolean {}
impl Frozen for boolean_struct::True {}
impl Frozen for boolean_struct::False {}
mod tests {
#[test]
fn test_compare_op_matches() {
use super::CompareOp;
use std::cmp::Ordering;
assert!(CompareOp::Eq.matches(Ordering::Equal));
assert!(CompareOp::Ne.matches(Ordering::Less));
assert!(CompareOp::Ge.matches(Ordering::Greater));
assert!(CompareOp::Gt.matches(Ordering::Greater));
assert!(CompareOp::Le.matches(Ordering::Equal));
assert!(CompareOp::Lt.matches(Ordering::Less));
}
}