diff --git a/CHANGELOG.md b/CHANGELOG.md index 0e75f883efb..4bb32448f8b 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0. - Support PyPy 3.7. [#1538](https://github.com/PyO3/pyo3/pull/1538) ### Added +- Add conversions for `[T; N]` for all `N` on Rust 1.51 and up. [#1128](https://github.com/PyO3/pyo3/pull/1128) - Add conversions between `OsStr`/`OsString`/`Path`/`PathBuf` and Python strings. [#1379](https://github.com/PyO3/pyo3/pull/1379) - Add `#[pyo3(from_py_with = "...")]` attribute for function arguments and struct fields to override the default from-Python conversion. [#1411](https://github.com/PyO3/pyo3/pull/1411) - Add FFI definition `PyCFunction_CheckExact` for Python 3.9 and later. [#1425](https://github.com/PyO3/pyo3/pull/1425) diff --git a/build.rs b/build.rs index 55e4b08b420..c67e92bc204 100644 --- a/build.rs +++ b/build.rs @@ -746,6 +746,17 @@ fn ensure_python_version(interpreter_config: &InterpreterConfig) -> Result<()> { Ok(()) } +fn rustc_minor_version() -> Option { + let rustc = env::var_os("RUSTC")?; + let output = Command::new(rustc).arg("--version").output().ok()?; + let version = core::str::from_utf8(&output.stdout).ok()?; + let mut pieces = version.split('.'); + if pieces.next() != Some("rustc 1") { + return None; + } + pieces.next()?.parse().ok() +} + fn emit_cargo_configuration(interpreter_config: &InterpreterConfig) -> Result<()> { let target_os = cargo_env_var("CARGO_CFG_TARGET_OS").unwrap(); let is_extension_module = cargo_env_var("CARGO_FEATURE_EXTENSION_MODULE").is_some(); @@ -850,6 +861,12 @@ fn emit_cargo_configuration(interpreter_config: &InterpreterConfig) -> Result<() println!("cargo:rustc-cfg=py_sys_config=\"{}\"", flag) } + // Enable use of const generics on Rust 1.51 and greater + + if rustc_minor_version().unwrap_or(0) >= 51 { + println!("cargo:rustc-cfg=min_const_generics"); + } + Ok(()) } diff --git a/src/conversions/array.rs b/src/conversions/array.rs new file mode 100644 index 00000000000..1be641a0f07 --- /dev/null +++ b/src/conversions/array.rs @@ -0,0 +1,288 @@ +use crate::{exceptions, PyErr}; + +#[cfg(min_const_generics)] +mod min_const_generics { + use super::invalid_sequence_length; + use crate::{FromPyObject, IntoPy, PyAny, PyObject, PyResult, PyTryFrom, Python, ToPyObject}; + + impl IntoPy for [T; N] + where + T: ToPyObject, + { + fn into_py(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>, + { + #[cfg(not(feature = "nightly"))] + fn extract(obj: &'a PyAny) -> PyResult { + create_array_from_obj(obj) + } + + #[cfg(feature = "nightly")] + default fn extract(obj: &'a PyAny) -> PyResult { + create_array_from_obj(obj) + } + } + + #[cfg(feature = "nightly")] + impl<'source, T, const N: usize> FromPyObject<'source> for [T; N] + where + for<'a> T: Default + FromPyObject<'a> + crate::buffer::Element, + { + fn extract(obj: &'source PyAny) -> PyResult { + use crate::{AsPyPointer, PyNativeType}; + // first try buffer protocol + if unsafe { crate::ffi::PyObject_CheckBuffer(obj.as_ptr()) } == 1 { + if let Ok(buf) = crate::buffer::PyBuffer::get(obj) { + let mut array = [T::default(); N]; + if buf.dimensions() == 1 && buf.copy_to_slice(obj.py(), &mut array).is_ok() { + buf.release(obj.py()); + return Ok(array); + } + buf.release(obj.py()); + } + } + 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 = ::try_from(obj)?; + let seq_len = seq.len()? as usize; + if seq_len != N { + return Err(invalid_sequence_length(N, seq_len)); + } + array_try_from_fn(|idx| seq.get_item(idx as isize).and_then(PyAny::extract)) + } + + // TODO use std::array::try_from_fn, if that stabilises: + // (https://github.com/rust-lang/rust/pull/75644) + fn array_try_from_fn(mut cb: F) -> Result<[T; N], E> + where + F: FnMut(usize) -> Result, + { + // Helper to safely create arrays since the standard library doesn't + // provide one yet. Shouldn't be necessary in the future. + struct ArrayGuard { + dst: *mut T, + initialized: usize, + } + + impl Drop for ArrayGuard { + 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); + } + } + } + + // [MaybeUninit; N] would be "nicer" but is actually difficult to create - there are nightly + // APIs which would make this easier. + let mut array: core::mem::MaybeUninit<[T; N]> = core::mem::MaybeUninit::uninit(); + let mut guard: ArrayGuard = 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 test { + 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| { + 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"); + }) + } + + // https://stackoverflow.com/a/59211505 + fn catch_unwind_silent(f: F) -> std::thread::Result + 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::{FromPyObject, IntoPy, PyAny, PyObject, PyResult, PyTryFrom, Python, ToPyObject}; + + macro_rules! array_impls { + ($($N:expr),+) => { + $( + impl IntoPy for [T; $N] + where + T: ToPyObject + { + fn into_py(self, py: Python) -> PyObject { + self.as_ref().to_object(py) + } + } + + impl<'a, T> FromPyObject<'a> for [T; $N] + where + T: Copy + Default + FromPyObject<'a>, + { + #[cfg(not(feature = "nightly"))] + fn extract(obj: &'a PyAny) -> PyResult { + let mut array = [T::default(); $N]; + extract_sequence_into_slice(obj, &mut array)?; + Ok(array) + } + + #[cfg(feature = "nightly")] + default fn extract(obj: &'a PyAny) -> PyResult { + let mut array = [T::default(); $N]; + extract_sequence_into_slice(obj, &mut array)?; + Ok(array) + } + } + + #[cfg(feature = "nightly")] + impl<'source, T> FromPyObject<'source> for [T; $N] + where + for<'a> T: Default + FromPyObject<'a> + crate::buffer::Element, + { + fn extract(obj: &'source PyAny) -> PyResult { + let mut array = [T::default(); $N]; + // first try buffer protocol + if unsafe { crate::ffi::PyObject_CheckBuffer(obj.as_ptr()) } == 1 { + if let Ok(buf) = crate::buffer::PyBuffer::get(obj) { + if buf.dimensions() == 1 && buf.copy_to_slice(obj.py(), &mut array).is_ok() { + buf.release(obj.py()); + return Ok(array); + } + buf.release(obj.py()); + } + } + // fall back to sequence protocol + 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 = ::try_from(obj)?; + let seq_len = seq.len()? as usize; + 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::()?; + } + 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 test { + use crate::{PyResult, Python}; + + #[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_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)" + ); + }) + } +} diff --git a/src/conversions/mod.rs b/src/conversions/mod.rs index a7ccff995ac..60c57fc96a0 100644 --- a/src/conversions/mod.rs +++ b/src/conversions/mod.rs @@ -1,5 +1,5 @@ -//! This module contains conversions between non-String Rust object and their string representation -//! in Python +//! This module contains conversions between various Rust object and their representation in Python. +mod array; mod osstr; mod path; diff --git a/src/types/list.rs b/src/types/list.rs index 4a0586e4fcd..019693b12b5 100644 --- a/src/types/list.rs +++ b/src/types/list.rs @@ -178,26 +178,6 @@ where } } -macro_rules! array_impls { - ($($N:expr),+) => { - $( - impl IntoPy for [T; $N] - where - T: ToPyObject - { - fn into_py(self, py: Python) -> PyObject { - self.as_ref().to_object(py) - } - } - )+ - } -} - -array_impls!( - 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, - 26, 27, 28, 29, 30, 31, 32 -); - impl ToPyObject for Vec where T: ToPyObject, diff --git a/src/types/sequence.rs b/src/types/sequence.rs index 423021d02a3..6432c4a06d0 100644 --- a/src/types/sequence.rs +++ b/src/types/sequence.rs @@ -1,7 +1,6 @@ // Copyright (c) 2017-present PyO3 Project and Contributors use crate::err::{self, PyDowncastError, PyErr, PyResult}; -use crate::exceptions; use crate::ffi::{self, Py_ssize_t}; use crate::instance::PyNativeType; use crate::types::{PyAny, PyList, PyTuple}; @@ -257,59 +256,6 @@ impl PySequence { } } -macro_rules! array_impls { - ($($N:expr),+) => { - $( - impl<'a, T> FromPyObject<'a> for [T; $N] - where - T: Copy + Default + FromPyObject<'a>, - { - #[cfg(not(feature = "nightly"))] - fn extract(obj: &'a PyAny) -> PyResult { - let mut array = [T::default(); $N]; - extract_sequence_into_slice(obj, &mut array)?; - Ok(array) - } - - #[cfg(feature = "nightly")] - default fn extract(obj: &'a PyAny) -> PyResult { - let mut array = [T::default(); $N]; - extract_sequence_into_slice(obj, &mut array)?; - Ok(array) - } - } - - #[cfg(feature = "nightly")] - impl<'source, T> FromPyObject<'source> for [T; $N] - where - for<'a> T: Default + FromPyObject<'a> + crate::buffer::Element, - { - fn extract(obj: &'source PyAny) -> PyResult { - let mut array = [T::default(); $N]; - // first try buffer protocol - if unsafe { ffi::PyObject_CheckBuffer(obj.as_ptr()) } == 1 { - if let Ok(buf) = crate::buffer::PyBuffer::get(obj) { - if buf.dimensions() == 1 && buf.copy_to_slice(obj.py(), &mut array).is_ok() { - buf.release(obj.py()); - return Ok(array); - } - buf.release(obj.py()); - } - } - // fall back to sequence protocol - extract_sequence_into_slice(obj, &mut array)?; - Ok(array) - } - } - )+ - } -} - -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 -); - impl<'a, T> FromPyObject<'a> for Vec where T: FromPyObject<'a>, @@ -357,22 +303,6 @@ where Ok(v) } -fn extract_sequence_into_slice<'s, T>(obj: &'s PyAny, slice: &mut [T]) -> PyResult<()> -where - T: FromPyObject<'s>, -{ - let seq = ::try_from(obj)?; - if seq.len()? as usize != slice.len() { - return Err(exceptions::PyBufferError::new_err( - "Slice length does not match buffer length.", - )); - } - for (value, item) in slice.iter_mut().zip(seq.iter()?) { - *value = item?.extract::()?; - } - Ok(()) -} - impl<'v> PyTryFrom<'v> for PySequence { fn try_from>(value: V) -> Result<&'v PySequence, PyDowncastError<'v>> { let value = value.into(); @@ -706,18 +636,6 @@ mod test { assert!(v == [1, 2, 3, 4]); } - #[test] - fn test_extract_bytearray_to_array() { - let gil = Python::acquire_gil(); - let py = gil.python(); - let v: [u8; 3] = py - .eval("bytearray(b'abc')", None, None) - .unwrap() - .extract() - .unwrap(); - assert!(&v == b"abc"); - } - #[test] fn test_extract_bytearray_to_vec() { let gil = Python::acquire_gil();