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Add wrapper for PyASCIIObject state bitfield accesses based on bindgen

This commit is contained in:
Fabio Valentini 2023-03-05 20:03:14 +01:00
parent 713c02a910
commit 40d6d4797f
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GPG Key ID: 5AC5F572E5D410AF
5 changed files with 268 additions and 45 deletions
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1
newsfragments/3015.added.md Normal file
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@ -0,0 +1 @@
Support `PyASCIIObject` / `PyUnicode` and associated methods on big-endian architectures.

273
pyo3-ffi/src/cpython/unicodeobject.rs
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@ -30,6 +30,184 @@ use std::os::raw::{c_char, c_int, c_uint, c_void};
// skipped Py_UNICODE_HIGH_SURROGATE
// skipped Py_UNICODE_LOW_SURROGATE
// generated by bindgen v0.63.0 (with small adaptations)
#[repr(C)]
struct BitfieldUnit<Storage> {
storage: Storage,
}
impl<Storage> BitfieldUnit<Storage> {
#[inline]
pub const fn new(storage: Storage) -> Self {
Self { storage }
}
}
impl<Storage> BitfieldUnit<Storage>
where
Storage: AsRef<[u8]> + AsMut<[u8]>,
{
#[inline]
fn get_bit(&self, index: usize) -> bool {
debug_assert!(index / 8 < self.storage.as_ref().len());
let byte_index = index / 8;
let byte = self.storage.as_ref()[byte_index];
let bit_index = if cfg!(target_endian = "big") {
7 - (index % 8)
} else {
index % 8
};
let mask = 1 << bit_index;
byte & mask == mask
}
#[inline]
fn set_bit(&mut self, index: usize, val: bool) {
debug_assert!(index / 8 < self.storage.as_ref().len());
let byte_index = index / 8;
let byte = &mut self.storage.as_mut()[byte_index];
let bit_index = if cfg!(target_endian = "big") {
7 - (index % 8)
} else {
index % 8
};
let mask = 1 << bit_index;
if val {
*byte |= mask;
} else {
*byte &= !mask;
}
}
#[inline]
fn get(&self, bit_offset: usize, bit_width: u8) -> u64 {
debug_assert!(bit_width <= 64);
debug_assert!(bit_offset / 8 < self.storage.as_ref().len());
debug_assert!((bit_offset + (bit_width as usize)) / 8 <= self.storage.as_ref().len());
let mut val = 0;
for i in 0..(bit_width as usize) {
if self.get_bit(i + bit_offset) {
let index = if cfg!(target_endian = "big") {
bit_width as usize - 1 - i
} else {
i
};
val |= 1 << index;
}
}
val
}
#[inline]
fn set(&mut self, bit_offset: usize, bit_width: u8, val: u64) {
debug_assert!(bit_width <= 64);
debug_assert!(bit_offset / 8 < self.storage.as_ref().len());
debug_assert!((bit_offset + (bit_width as usize)) / 8 <= self.storage.as_ref().len());
for i in 0..(bit_width as usize) {
let mask = 1 << i;
let val_bit_is_set = val & mask == mask;
let index = if cfg!(target_endian = "big") {
bit_width as usize - 1 - i
} else {
i
};
self.set_bit(index + bit_offset, val_bit_is_set);
}
}
}
// generated by bindgen v0.63.0 (with small adaptations)
// The same code is generated for Python 3.7, 3.8, 3.9, 3.10, and 3.11, but the "ready" field
// has been removed from Python 3.12.
/// Wrapper around the `PyASCIIObject.state` bitfield with getters and setters that work
/// on most little- and big-endian architectures.
///
/// Memory layout of C bitfields is implementation defined, so these functions are still
/// unsafe. Users must verify that they work as expected on the architectures they target.
#[repr(C)]
#[repr(align(4))]
struct PyASCIIObjectState {
_bitfield_align: [u8; 0],
_bitfield: BitfieldUnit<[u8; 4usize]>,
}
// c_uint and u32 are not necessarily the same type on all targets / architectures
#[allow(clippy::useless_transmute)]
impl PyASCIIObjectState {
#[inline]
unsafe fn interned(&self) -> c_uint {
std::mem::transmute(self._bitfield.get(0usize, 2u8) as u32)
}
#[inline]
unsafe fn set_interned(&mut self, val: c_uint) {
let val: u32 = std::mem::transmute(val);
self._bitfield.set(0usize, 2u8, val as u64)
}
#[inline]
unsafe fn kind(&self) -> c_uint {
std::mem::transmute(self._bitfield.get(2usize, 3u8) as u32)
}
#[inline]
unsafe fn set_kind(&mut self, val: c_uint) {
let val: u32 = std::mem::transmute(val);
self._bitfield.set(2usize, 3u8, val as u64)
}
#[inline]
unsafe fn compact(&self) -> c_uint {
std::mem::transmute(self._bitfield.get(5usize, 1u8) as u32)
}
#[inline]
unsafe fn set_compact(&mut self, val: c_uint) {
let val: u32 = std::mem::transmute(val);
self._bitfield.set(5usize, 1u8, val as u64)
}
#[inline]
unsafe fn ascii(&self) -> c_uint {
std::mem::transmute(self._bitfield.get(6usize, 1u8) as u32)
}
#[inline]
unsafe fn set_ascii(&mut self, val: c_uint) {
let val: u32 = std::mem::transmute(val);
self._bitfield.set(6usize, 1u8, val as u64)
}
#[inline]
unsafe fn ready(&self) -> c_uint {
std::mem::transmute(self._bitfield.get(7usize, 1u8) as u32)
}
#[inline]
unsafe fn set_ready(&mut self, val: c_uint) {
let val: u32 = std::mem::transmute(val);
self._bitfield.set(7usize, 1u8, val as u64)
}
}
impl From<u32> for PyASCIIObjectState {
#[inline]
fn from(value: u32) -> Self {
PyASCIIObjectState {
_bitfield_align: [],
_bitfield: BitfieldUnit::new(value.to_ne_bytes()),
}
}
}
impl From<PyASCIIObjectState> for u32 {
#[inline]
fn from(value: PyASCIIObjectState) -> Self {
u32::from_ne_bytes(value._bitfield.storage)
}
}
#[repr(C)]
pub struct PyASCIIObject {
pub ob_base: PyObject,
@ -52,34 +230,98 @@ pub struct PyASCIIObject {
}
/// Interacting with the bitfield is not actually well-defined, so we mark these APIs unsafe.
///
/// In addition, they are disabled on big-endian architectures to restrict this to most "common"
/// platforms, which are at least tested on CI and appear to be sound.
#[cfg(target_endian = "little")]
impl PyASCIIObject {
/// Get the `interned` field of the [`PyASCIIObject`] state bitfield.
///
/// Returns one of: [`SSTATE_NOT_INTERNED`], [`SSTATE_INTERNED_MORTAL`], [`SSTATE_INTERNED_IMMORTAL`]
#[inline]
pub unsafe fn interned(&self) -> c_uint {
self.state & 3
PyASCIIObjectState::from(self.state).interned()
}
/// Set the `interned` field of the [`PyASCIIObject`] state bitfield.
///
/// Calling this function with an argument that is not [`SSTATE_NOT_INTERNED`],
/// [`SSTATE_INTERNED_MORTAL`], or [`SSTATE_INTERNED_IMMORTAL`] is invalid.
#[inline]
pub unsafe fn set_interned(&mut self, val: c_uint) {
let mut state = PyASCIIObjectState::from(self.state);
state.set_interned(val);
self.state = u32::from(state);
}
/// Get the `kind` field of the [`PyASCIIObject`] state bitfield.
///
/// Returns one of: [`PyUnicode_WCHAR_KIND`], [`PyUnicode_1BYTE_KIND`], [`PyUnicode_2BYTE_KIND`],
/// [`PyUnicode_4BYTE_KIND`]
#[inline]
pub unsafe fn kind(&self) -> c_uint {
(self.state >> 2) & 7
PyASCIIObjectState::from(self.state).kind()
}
/// Set the `kind` field of the [`PyASCIIObject`] state bitfield.
///
/// Calling this function with an argument that is not [`PyUnicode_WCHAR_KIND`], [`PyUnicode_1BYTE_KIND`],
/// [`PyUnicode_2BYTE_KIND`], or [`PyUnicode_4BYTE_KIND`] is invalid.
#[inline]
pub unsafe fn set_kind(&mut self, val: c_uint) {
let mut state = PyASCIIObjectState::from(self.state);
state.set_kind(val);
self.state = u32::from(state);
}
/// Get the `compact` field of the [`PyASCIIObject`] state bitfield.
///
/// Returns either `0` or `1`.
#[inline]
pub unsafe fn compact(&self) -> c_uint {
(self.state >> 5) & 1
PyASCIIObjectState::from(self.state).compact()
}
/// Set the `compact` flag of the [`PyASCIIObject`] state bitfield.
///
/// Calling this function with an argument that is neither `0` nor `1` is invalid.
#[inline]
pub unsafe fn set_compact(&mut self, val: c_uint) {
let mut state = PyASCIIObjectState::from(self.state);
state.set_compact(val);
self.state = u32::from(state);
}
/// Get the `ascii` field of the [`PyASCIIObject`] state bitfield.
///
/// Returns either `0` or `1`.
#[inline]
pub unsafe fn ascii(&self) -> c_uint {
(self.state >> 6) & 1
PyASCIIObjectState::from(self.state).ascii()
}
/// Set the `ascii` flag of the [`PyASCIIObject`] state bitfield.
///
/// Calling this function with an argument that is neither `0` nor `1` is invalid.
#[inline]
pub unsafe fn set_ascii(&mut self, val: c_uint) {
let mut state = PyASCIIObjectState::from(self.state);
state.set_ascii(val);
self.state = u32::from(state);
}
/// Get the `ready` field of the [`PyASCIIObject`] state bitfield.
///
/// Returns either `0` or `1`.
#[inline]
pub unsafe fn ready(&self) -> c_uint {
(self.state >> 7) & 1
PyASCIIObjectState::from(self.state).ready()
}
/// Set the `ready` flag of the [`PyASCIIObject`] state bitfield.
///
/// Calling this function with an argument that is neither `0` nor `1` is invalid.
#[inline]
pub unsafe fn set_ready(&mut self, val: c_uint) {
let mut state = PyASCIIObjectState::from(self.state);
state.set_ready(val);
self.state = u32::from(state);
}
}
@ -120,7 +362,6 @@ pub const SSTATE_INTERNED_MORTAL: c_uint = 1;
pub const SSTATE_INTERNED_IMMORTAL: c_uint = 2;
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_IS_ASCII(op: *mut PyObject) -> c_uint {
debug_assert!(crate::PyUnicode_Check(op) != 0);
debug_assert!(PyUnicode_IS_READY(op) != 0);
@ -129,13 +370,11 @@ pub unsafe fn PyUnicode_IS_ASCII(op: *mut PyObject) -> c_uint {
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_IS_COMPACT(op: *mut PyObject) -> c_uint {
(*(op as *mut PyASCIIObject)).compact()
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_IS_COMPACT_ASCII(op: *mut PyObject) -> c_uint {
((*(op as *mut PyASCIIObject)).ascii() != 0 && PyUnicode_IS_COMPACT(op) != 0).into()
}
@ -149,25 +388,21 @@ pub const PyUnicode_2BYTE_KIND: c_uint = 2;
pub const PyUnicode_4BYTE_KIND: c_uint = 4;
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_1BYTE_DATA(op: *mut PyObject) -> *mut Py_UCS1 {
PyUnicode_DATA(op) as *mut Py_UCS1
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_2BYTE_DATA(op: *mut PyObject) -> *mut Py_UCS2 {
PyUnicode_DATA(op) as *mut Py_UCS2
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_4BYTE_DATA(op: *mut PyObject) -> *mut Py_UCS4 {
PyUnicode_DATA(op) as *mut Py_UCS4
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_KIND(op: *mut PyObject) -> c_uint {
debug_assert!(crate::PyUnicode_Check(op) != 0);
debug_assert!(PyUnicode_IS_READY(op) != 0);
@ -176,7 +411,6 @@ pub unsafe fn PyUnicode_KIND(op: *mut PyObject) -> c_uint {
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn _PyUnicode_COMPACT_DATA(op: *mut PyObject) -> *mut c_void {
if PyUnicode_IS_ASCII(op) != 0 {
(op as *mut PyASCIIObject).offset(1) as *mut c_void
@ -186,7 +420,6 @@ pub unsafe fn _PyUnicode_COMPACT_DATA(op: *mut PyObject) -> *mut c_void {
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn _PyUnicode_NONCOMPACT_DATA(op: *mut PyObject) -> *mut c_void {
debug_assert!(!(*(op as *mut PyUnicodeObject)).data.any.is_null());
@ -194,7 +427,6 @@ pub unsafe fn _PyUnicode_NONCOMPACT_DATA(op: *mut PyObject) -> *mut c_void {
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_DATA(op: *mut PyObject) -> *mut c_void {
debug_assert!(crate::PyUnicode_Check(op) != 0);
@ -210,7 +442,6 @@ pub unsafe fn PyUnicode_DATA(op: *mut PyObject) -> *mut c_void {
// skipped PyUnicode_READ_CHAR
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_GET_LENGTH(op: *mut PyObject) -> Py_ssize_t {
debug_assert!(crate::PyUnicode_Check(op) != 0);
debug_assert!(PyUnicode_IS_READY(op) != 0);
@ -219,7 +450,6 @@ pub unsafe fn PyUnicode_GET_LENGTH(op: *mut PyObject) -> Py_ssize_t {
}
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_IS_READY(op: *mut PyObject) -> c_uint {
(*(op as *mut PyASCIIObject)).ready()
}
@ -227,7 +457,6 @@ pub unsafe fn PyUnicode_IS_READY(op: *mut PyObject) -> c_uint {
#[cfg(not(Py_3_12))]
#[cfg_attr(Py_3_10, deprecated(note = "Python 3.10"))]
#[inline]
#[cfg(target_endian = "little")]
pub unsafe fn PyUnicode_READY(op: *mut PyObject) -> c_int {
debug_assert!(crate::PyUnicode_Check(op) != 0);

17
src/ffi/tests.rs
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@ -1,9 +1,7 @@
use crate::ffi::*;
use crate::{types::PyDict, AsPyPointer, IntoPy, Py, PyAny, Python};
#[cfg(target_endian = "little")]
use crate::types::PyString;
#[cfg(target_endian = "little")]
use libc::wchar_t;
#[cfg_attr(target_arch = "wasm32", ignore)] // DateTime import fails on wasm for mysterious reasons
@ -108,7 +106,6 @@ fn test_timezone_from_offset_and_name() {
})
}
#[cfg(target_endian = "little")]
#[test]
fn ascii_object_bitfield() {
let ob_base: PyObject = unsafe { std::mem::zeroed() };
@ -118,7 +115,7 @@ fn ascii_object_bitfield() {
length: 0,
#[cfg(not(PyPy))]
hash: 0,
state: 0,
state: 0u32,
wstr: std::ptr::null_mut() as *mut wchar_t,
};
@ -130,27 +127,26 @@ fn ascii_object_bitfield() {
assert_eq!(o.ready(), 0);
for i in 0..4 {
o.state = i;
o.set_interned(i);
assert_eq!(o.interned(), i);
}
for i in 0..8 {
o.state = i << 2;
o.set_kind(i);
assert_eq!(o.kind(), i);
}
o.state = 1 << 5;
o.set_compact(1);
assert_eq!(o.compact(), 1);
o.state = 1 << 6;
o.set_ascii(1);
assert_eq!(o.ascii(), 1);
o.state = 1 << 7;
o.set_ready(1);
assert_eq!(o.ready(), 1);
}
}
#[cfg(target_endian = "little")]
#[test]
#[cfg_attr(Py_3_10, allow(deprecated))]
fn ascii() {
@ -191,7 +187,6 @@ fn ascii() {
})
}
#[cfg(target_endian = "little")]
#[test]
#[cfg_attr(Py_3_10, allow(deprecated))]
fn ucs4() {

2
src/types/mod.rs
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@ -36,7 +36,7 @@ pub use self::pysuper::PySuper;
pub use self::sequence::PySequence;
pub use self::set::PySet;
pub use self::slice::{PySlice, PySliceIndices};
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
pub use self::string::PyStringData;
pub use self::string::{PyString, PyString as PyUnicode};
pub use self::traceback::PyTraceback;

20
src/types/string.rs
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@ -1,6 +1,6 @@
// Copyright (c) 2017-present PyO3 Project and Contributors
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
use crate::exceptions::PyUnicodeDecodeError;
use crate::types::PyBytes;
use crate::{ffi, AsPyPointer, PyAny, PyResult, Python};
@ -12,7 +12,7 @@ use std::str;
///
/// Python internally stores strings in various representations. This enumeration
/// represents those variations.
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum PyStringData<'a> {
/// UCS1 representation.
@ -25,7 +25,7 @@ pub enum PyStringData<'a> {
Ucs4(&'a [u32]),
}
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
impl<'a> PyStringData<'a> {
/// Obtain the raw bytes backing this instance as a [u8] slice.
pub fn as_bytes(&self) -> &[u8] {
@ -238,9 +238,7 @@ impl PyString {
///
/// By using this API, you accept responsibility for testing that PyStringData behaves as
/// expected on the targets where you plan to distribute your software.
///
/// For example, it is known not to work on big-endian platforms.
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
pub unsafe fn data(&self) -> PyResult<PyStringData<'_>> {
let ptr = self.as_ptr();
@ -284,7 +282,7 @@ mod tests {
use super::*;
use crate::Python;
use crate::{PyObject, ToPyObject};
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
use std::borrow::Cow;
#[test]
@ -347,7 +345,7 @@ mod tests {
}
#[test]
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
fn test_string_data_ucs1() {
Python::with_gil(|py| {
let s = PyString::new(py, "hello, world");
@ -360,7 +358,7 @@ mod tests {
}
#[test]
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
fn test_string_data_ucs1_invalid() {
Python::with_gil(|py| {
// 0xfe is not allowed in UTF-8.
@ -386,7 +384,7 @@ mod tests {
}
#[test]
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
fn test_string_data_ucs2() {
Python::with_gil(|py| {
let s = py.eval("'foo\\ud800'", None, None).unwrap();
@ -428,7 +426,7 @@ mod tests {
}
#[test]
#[cfg(all(not(Py_LIMITED_API), target_endian = "little"))]
#[cfg(not(Py_LIMITED_API))]
fn test_string_data_ucs4() {
Python::with_gil(|py| {
let s = "哈哈🐈";