use crate::{exceptions, PyErr};
#[cfg(min_const_generics)]
mod min_const_generics {
use super::invalid_sequence_length;
use crate::conversion::{AsPyPointer, IntoPyPointer};
use crate::types::PySequence;
use crate::{
ffi, FromPyObject, IntoPy, Py, PyAny, PyDowncastError, PyObject, PyResult, Python,
ToPyObject,
};
impl<T, const N: usize> IntoPy<PyObject> for [T; N]
where
T: IntoPy<PyObject>,
{
fn into_py(self, py: Python<'_>) -> PyObject {
unsafe {
#[allow(deprecated)] let elements = std::array::IntoIter::new(self);
let len = N as ffi::Py_ssize_t;
let ptr = ffi::PyList_New(len);
let list: Py<PyAny> = Py::from_owned_ptr(py, ptr);
for (i, obj) in (0..len).zip(elements) {
let obj = obj.into_py(py).into_ptr();
#[cfg(not(Py_LIMITED_API))]
ffi::PyList_SET_ITEM(ptr, i, obj);
#[cfg(Py_LIMITED_API)]
ffi::PyList_SetItem(ptr, i, obj);
}
list
}
}
}
impl<T, const N: usize> ToPyObject for [T; N]
where
T: ToPyObject,
{
fn to_object(&self, py: Python<'_>) -> PyObject {
self.as_ref().to_object(py)
}
}
impl<'a, T, const N: usize> FromPyObject<'a> for [T; N]
where
T: FromPyObject<'a>,
{
fn extract(obj: &'a PyAny) -> PyResult<Self> {
create_array_from_obj(obj)
}
}
fn create_array_from_obj<'s, T, const N: usize>(obj: &'s PyAny) -> PyResult<[T; N]>
where
T: FromPyObject<'s>,
{
let seq: &PySequence = unsafe {
if ffi::PySequence_Check(obj.as_ptr()) != 0 {
obj.downcast_unchecked()
} else {
return Err(PyDowncastError::new(obj, "Sequence").into());
}
};
let seq_len = seq.len()?;
if seq_len != N {
return Err(invalid_sequence_length(N, seq_len));
}
array_try_from_fn(|idx| seq.get_item(idx).and_then(PyAny::extract))
}
fn array_try_from_fn<E, F, T, const N: usize>(mut cb: F) -> Result<[T; N], E>
where
F: FnMut(usize) -> Result<T, E>,
{
struct ArrayGuard<T, const N: usize> {
dst: *mut T,
initialized: usize,
}
impl<T, const N: usize> Drop for ArrayGuard<T, N> {
fn drop(&mut self) {
debug_assert!(self.initialized <= N);
let initialized_part =
core::ptr::slice_from_raw_parts_mut(self.dst, self.initialized);
unsafe {
core::ptr::drop_in_place(initialized_part);
}
}
}
let mut array: core::mem::MaybeUninit<[T; N]> = core::mem::MaybeUninit::uninit();
let mut guard: ArrayGuard<T, N> = ArrayGuard {
dst: array.as_mut_ptr() as _,
initialized: 0,
};
unsafe {
let mut value_ptr = array.as_mut_ptr() as *mut T;
for i in 0..N {
core::ptr::write(value_ptr, cb(i)?);
value_ptr = value_ptr.offset(1);
guard.initialized += 1;
}
core::mem::forget(guard);
Ok(array.assume_init())
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::{
panic,
sync::atomic::{AtomicUsize, Ordering},
};
#[test]
fn array_try_from_fn() {
static DROP_COUNTER: AtomicUsize = AtomicUsize::new(0);
struct CountDrop;
impl Drop for CountDrop {
fn drop(&mut self) {
DROP_COUNTER.fetch_add(1, Ordering::SeqCst);
}
}
let _ = catch_unwind_silent(move || {
let _: Result<[CountDrop; 4], ()> = super::array_try_from_fn(|idx| {
#[allow(clippy::manual_assert)]
if idx == 2 {
panic!("peek a boo");
}
Ok(CountDrop)
});
});
assert_eq!(DROP_COUNTER.load(Ordering::SeqCst), 2);
}
#[test]
fn test_extract_bytearray_to_array() {
Python::with_gil(|py| {
let v: [u8; 33] = py
.eval(
"bytearray(b'abcabcabcabcabcabcabcabcabcabcabc')",
None,
None,
)
.unwrap()
.extract()
.unwrap();
assert!(&v == b"abcabcabcabcabcabcabcabcabcabcabc");
})
}
fn catch_unwind_silent<F, R>(f: F) -> std::thread::Result<R>
where
F: FnOnce() -> R + panic::UnwindSafe,
{
let prev_hook = panic::take_hook();
panic::set_hook(Box::new(|_| {}));
let result = panic::catch_unwind(f);
panic::set_hook(prev_hook);
result
}
}
}
#[cfg(not(min_const_generics))]
mod array_impls {
use super::invalid_sequence_length;
use crate::conversion::{AsPyPointer, IntoPyPointer};
use crate::types::PySequence;
use crate::{
ffi, FromPyObject, IntoPy, Py, PyAny, PyDowncastError, PyObject, PyResult, Python,
ToPyObject,
};
use std::mem::{transmute_copy, ManuallyDrop};
macro_rules! array_impls {
($($N:expr),+) => {
$(
impl<T> IntoPy<PyObject> for [T; $N]
where
T: IntoPy<PyObject>
{
fn into_py(self, py: Python<'_>) -> PyObject {
struct ArrayGuard<T> {
elements: [ManuallyDrop<T>; $N],
start: usize,
}
impl<T> Drop for ArrayGuard<T> {
fn drop(&mut self) {
unsafe {
let needs_drop = self.elements.get_mut(self.start..).unwrap();
for item in needs_drop {
ManuallyDrop::drop(item);
}
}
}
}
unsafe {
let ptr = ffi::PyList_New($N as ffi::Py_ssize_t);
let list: Py<PyAny> = Py::from_owned_ptr(py, ptr);
let slf = ManuallyDrop::new(self);
let mut guard = ArrayGuard {
elements: transmute_copy(&slf),
start: 0
};
for i in 0..$N {
let obj: T = ManuallyDrop::take(&mut guard.elements[i]);
guard.start += 1;
let obj = obj.into_py(py).into_ptr();
#[cfg(not(Py_LIMITED_API))]
ffi::PyList_SET_ITEM(ptr, i as ffi::Py_ssize_t, obj);
#[cfg(Py_LIMITED_API)]
ffi::PyList_SetItem(ptr, i as ffi::Py_ssize_t, obj);
}
std::mem::forget(guard);
list
}
}
}
impl<T> ToPyObject for [T; $N]
where
T: ToPyObject,
{
fn to_object(&self, py: Python<'_>) -> PyObject {
self.as_ref().to_object(py)
}
}
impl<'a, T> FromPyObject<'a> for [T; $N]
where
T: Copy + Default + FromPyObject<'a>,
{
fn extract(obj: &'a PyAny) -> PyResult<Self> {
let mut array = [T::default(); $N];
extract_sequence_into_slice(obj, &mut array)?;
Ok(array)
}
}
)+
}
}
#[cfg(not(min_const_generics))]
array_impls!(
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 26, 27, 28, 29, 30, 31, 32
);
#[cfg(not(min_const_generics))]
fn extract_sequence_into_slice<'s, T>(obj: &'s PyAny, slice: &mut [T]) -> PyResult<()>
where
T: FromPyObject<'s>,
{
let seq: &PySequence = unsafe {
if ffi::PySequence_Check(obj.as_ptr()) != 0 {
obj.downcast_unchecked()
} else {
return Err(PyDowncastError::new(obj, "Sequence").into());
}
};
let seq_len = seq.len()?;
if seq_len != slice.len() {
return Err(invalid_sequence_length(slice.len(), seq_len));
}
for (value, item) in slice.iter_mut().zip(seq.iter()?) {
*value = item?.extract::<T>()?;
}
Ok(())
}
}
fn invalid_sequence_length(expected: usize, actual: usize) -> PyErr {
exceptions::PyValueError::new_err(format!(
"expected a sequence of length {} (got {})",
expected, actual
))
}
#[cfg(test)]
mod tests {
use crate::{types::PyList, IntoPy, PyResult, Python, ToPyObject};
#[test]
fn test_extract_small_bytearray_to_array() {
Python::with_gil(|py| {
let v: [u8; 3] = py
.eval("bytearray(b'abc')", None, None)
.unwrap()
.extract()
.unwrap();
assert!(&v == b"abc");
});
}
#[test]
fn test_topyobject_array_conversion() {
Python::with_gil(|py| {
let array: [f32; 4] = [0.0, -16.0, 16.0, 42.0];
let pyobject = array.to_object(py);
let pylist: &PyList = pyobject.extract(py).unwrap();
assert_eq!(pylist[0].extract::<f32>().unwrap(), 0.0);
assert_eq!(pylist[1].extract::<f32>().unwrap(), -16.0);
assert_eq!(pylist[2].extract::<f32>().unwrap(), 16.0);
assert_eq!(pylist[3].extract::<f32>().unwrap(), 42.0);
});
}
#[test]
fn test_extract_invalid_sequence_length() {
Python::with_gil(|py| {
let v: PyResult<[u8; 3]> = py
.eval("bytearray(b'abcdefg')", None, None)
.unwrap()
.extract();
assert_eq!(
v.unwrap_err().to_string(),
"ValueError: expected a sequence of length 3 (got 7)"
);
})
}
#[test]
fn test_intopy_array_conversion() {
Python::with_gil(|py| {
let array: [f32; 4] = [0.0, -16.0, 16.0, 42.0];
let pyobject = array.into_py(py);
let pylist: &PyList = pyobject.extract(py).unwrap();
assert_eq!(pylist[0].extract::<f32>().unwrap(), 0.0);
assert_eq!(pylist[1].extract::<f32>().unwrap(), -16.0);
assert_eq!(pylist[2].extract::<f32>().unwrap(), 16.0);
assert_eq!(pylist[3].extract::<f32>().unwrap(), 42.0);
});
}
#[test]
fn test_extract_non_iterable_to_array() {
Python::with_gil(|py| {
let v = py.eval("42", None, None).unwrap();
v.extract::<i32>().unwrap();
v.extract::<[i32; 1]>().unwrap_err();
});
}
#[cfg(feature = "macros")]
#[test]
fn test_pyclass_intopy_array_conversion() {
#[crate::pyclass(crate = "crate")]
struct Foo;
Python::with_gil(|py| {
let array: [Foo; 8] = [Foo, Foo, Foo, Foo, Foo, Foo, Foo, Foo];
let pyobject = array.into_py(py);
let list: &PyList = pyobject.downcast(py).unwrap();
let _cell: &crate::PyCell<Foo> = list.get_item(4).unwrap().extract().unwrap();
});
}
}