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Copy pathbuffer.rs
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317 lines (277 loc) · 9.21 KB
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use crate::{
AsObject, PyObject, PyObjectRef, PyResult, TryFromBorrowedObject, TryFromObject,
VirtualMachine,
builtins::{PyBytes, PyStr, PyStrRef},
common::borrow::{BorrowedValue, BorrowedValueMut},
protocol::{BufferFlags, PyBuffer},
};
// Python/getargs.c
/// any bytes-like object. Like the `y*` format code for `PyArg_Parse` in CPython.
#[derive(Debug, Traverse)]
pub struct ArgBytesLike(PyBuffer);
impl PyObject {
pub fn try_bytes_like<F, R>(&self, vm: &VirtualMachine, f: F) -> PyResult<R>
where
F: FnOnce(&[u8]) -> R,
{
let buffer = PyBuffer::from_object(vm, self, BufferFlags::SIMPLE)?;
buffer
.as_contiguous()
.map(|x| f(&x))
.ok_or_else(|| vm.new_buffer_error("non-contiguous buffer is not a bytes-like object"))
}
pub fn try_rw_bytes_like<F, R>(&self, vm: &VirtualMachine, f: F) -> PyResult<R>
where
F: FnOnce(&mut [u8]) -> R,
{
let buffer = PyBuffer::from_object(vm, self, BufferFlags::WRITABLE)?;
buffer
.as_contiguous_mut()
.map(|mut x| f(&mut x))
.ok_or_else(|| vm.new_type_error("buffer is not a read-write bytes-like object"))
}
}
impl ArgBytesLike {
#[must_use]
pub fn borrow_buf(&self) -> BorrowedValue<'_, [u8]> {
unsafe { self.0.contiguous_unchecked() }
}
pub fn with_ref<F, R>(&self, f: F) -> R
where
F: FnOnce(&[u8]) -> R,
{
f(&self.borrow_buf())
}
/// The bytes to hand to an operation that may wait, and whatever keeps
/// them readable while it does.
///
/// `borrow_buf` may answer with a lock that every other thread writing to
/// the same object waits on, and a thread waiting on a lock never reaches
/// a safepoint, so keeping one across a wait for a peer, a pipe or a
/// signal stops the world from being stopped at all. Only storage owned
/// by `bytes` can be borrowed across that wait. Other exporters are copied:
/// an unlocked or readonly buffer may still alias writable raw memory.
pub fn borrow_buf_unlocked(&self, vm: &VirtualMachine) -> PyResult<UnlockedBuf<'_>> {
let borrowed = self.borrow_buf();
if !borrowed.is_locked() && self.source_object().downcast_ref::<PyBytes>().is_some() {
return Ok(UnlockedBuf::Borrowed(borrowed));
}
let mut copy = Vec::new();
copy.try_reserve_exact(borrowed.len())
.map_err(|_| vm.no_memory_error())?;
copy.extend_from_slice(&borrowed);
Ok(UnlockedBuf::Copied(copy))
}
#[must_use]
pub const fn len(&self) -> usize {
self.0.desc.len
}
/// The width of one item. Callers that read the buffer as bytes rather
/// than as whatever it holds have to ask, since a contiguous buffer of
/// wider items is contiguous all the same.
#[must_use]
pub const fn itemsize(&self) -> usize {
self.0.desc.itemsize
}
#[must_use]
pub const fn is_empty(&self) -> bool {
self.len() == 0
}
#[must_use]
pub fn as_object(&self) -> &PyObject {
&self.0.obj
}
/// The object whose storage is borrowed while this buffer is read: a view
/// borrows the object it looks at, not itself.
#[must_use]
pub fn source_object(&self) -> &PyObject {
self.0
.obj
.downcast_ref::<crate::builtins::PyMemoryView>()
.map_or(&self.0.obj, |view| view.viewed_object())
}
}
impl From<ArgBytesLike> for PyBuffer {
fn from(buffer: ArgBytesLike) -> Self {
buffer.0
}
}
impl From<ArgBytesLike> for PyObjectRef {
fn from(buffer: ArgBytesLike) -> Self {
buffer.as_object().to_owned()
}
}
impl ArgBytesLike {
fn from_request(vm: &VirtualMachine, obj: &PyObject, flags: BufferFlags) -> PyResult<Self> {
let buffer = PyBuffer::from_object(vm, obj, flags)?;
if buffer.desc.is_contiguous() {
Ok(Self(buffer))
} else {
Err(vm.new_buffer_error("non-contiguous buffer is not a bytes-like object"))
}
}
}
impl<'a> TryFromBorrowedObject<'a> for ArgBytesLike {
fn try_from_borrowed_object(vm: &VirtualMachine, obj: &'a PyObject) -> PyResult<Self> {
Self::from_request(vm, obj, BufferFlags::SIMPLE)
}
}
/// A bytes-like object asked for as `PyBUF_CONTIG_RO`, which is what a shape is
/// requested with rather than assumed.
#[derive(Debug, Traverse)]
pub struct ArgContiguousBytesLike(ArgBytesLike);
impl core::ops::Deref for ArgContiguousBytesLike {
type Target = ArgBytesLike;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl<'a> TryFromBorrowedObject<'a> for ArgContiguousBytesLike {
fn try_from_borrowed_object(vm: &VirtualMachine, obj: &'a PyObject) -> PyResult<Self> {
ArgBytesLike::from_request(vm, obj, BufferFlags::CONTIG_RO).map(Self)
}
}
/// Bytes that stay readable across a wait, from [`ArgBytesLike::borrow_buf_unlocked`].
#[derive(Debug)]
pub enum UnlockedBuf<'a> {
Borrowed(BorrowedValue<'a, [u8]>),
Copied(Vec<u8>),
}
impl core::ops::Deref for UnlockedBuf<'_> {
type Target = [u8];
fn deref(&self) -> &[u8] {
match self {
Self::Borrowed(b) => b,
Self::Copied(v) => v,
}
}
}
/// A memory buffer, read-write access. Like the `w*` format code for `PyArg_Parse` in CPython.
#[derive(Debug, Traverse)]
pub struct ArgMemoryBuffer(PyBuffer);
impl ArgMemoryBuffer {
#[must_use]
pub fn borrow_buf_mut(&self) -> BorrowedValueMut<'_, [u8]> {
unsafe { self.0.contiguous_mut_unchecked() }
}
pub fn with_ref<F, R>(&self, f: F) -> R
where
F: FnOnce(&mut [u8]) -> R,
{
f(&mut self.borrow_buf_mut())
}
#[must_use]
pub const fn len(&self) -> usize {
self.0.desc.len
}
#[must_use]
pub const fn is_empty(&self) -> bool {
self.len() == 0
}
/// The object whose storage is borrowed while this buffer is written: a
/// view borrows the object it looks at, not itself.
#[must_use]
pub fn source_object(&self) -> &PyObject {
self.0
.obj
.downcast_ref::<crate::builtins::PyMemoryView>()
.map_or(&self.0.obj, |view| view.viewed_object())
}
}
impl From<ArgMemoryBuffer> for PyBuffer {
fn from(buffer: ArgMemoryBuffer) -> Self {
buffer.0
}
}
impl<'a> TryFromBorrowedObject<'a> for ArgMemoryBuffer {
fn try_from_borrowed_object(vm: &VirtualMachine, obj: &'a PyObject) -> PyResult<Self> {
let buffer = PyBuffer::from_object(vm, obj, BufferFlags::WRITABLE).map_err(|exc| {
if obj.check_buffer() {
// An exporter that cannot serve the request leaves the argument
// simply the wrong kind of object, as `PyArg_Parse` reports it.
vm.new_type_error("buffer is not a read-write bytes-like object")
} else {
exc
}
})?;
if !buffer.desc.is_contiguous() {
Err(vm.new_buffer_error("non-contiguous buffer is not a bytes-like object"))
} else if buffer.desc.readonly {
Err(vm.new_type_error("buffer is not a read-write bytes-like object"))
} else {
Ok(Self(buffer))
}
}
}
/// A text string or bytes-like object. Like the `s*` format code for `PyArg_Parse` in CPython.
pub enum ArgStrOrBytesLike {
Buf(ArgBytesLike),
Str(PyStrRef),
}
impl ArgStrOrBytesLike {
#[must_use]
pub fn as_object(&self) -> &PyObject {
match self {
Self::Buf(b) => b.as_object(),
Self::Str(s) => s.as_object(),
}
}
}
impl TryFromObject for ArgStrOrBytesLike {
fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self> {
obj.downcast()
.map(Self::Str)
.or_else(|obj| ArgBytesLike::try_from_object(vm, obj).map(Self::Buf))
}
}
impl ArgStrOrBytesLike {
#[must_use]
pub fn borrow_bytes(&self) -> BorrowedValue<'_, [u8]> {
match self {
Self::Buf(b) => b.borrow_buf(),
Self::Str(s) => s.as_bytes().into(),
}
}
}
#[derive(Debug)]
pub enum ArgAsciiBuffer {
String(PyStrRef),
Buffer(ArgBytesLike),
}
impl TryFromObject for ArgAsciiBuffer {
fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self> {
match obj.downcast::<PyStr>() {
Ok(string) => {
if string.as_wtf8().is_ascii() {
Ok(Self::String(string))
} else {
Err(vm.new_value_error("string argument should contain only ASCII characters"))
}
}
Err(obj) => ArgBytesLike::try_from_object(vm, obj).map(ArgAsciiBuffer::Buffer),
}
}
}
impl ArgAsciiBuffer {
#[must_use]
pub fn len(&self) -> usize {
match self {
Self::String(s) => s.as_wtf8().len(),
Self::Buffer(buffer) => buffer.len(),
}
}
#[must_use]
pub fn is_empty(&self) -> bool {
self.len() == 0
}
#[inline]
pub fn with_ref<F, R>(&self, f: F) -> R
where
F: FnOnce(&[u8]) -> R,
{
match self {
Self::String(s) => f(s.as_bytes()),
Self::Buffer(buffer) => buffer.with_ref(f),
}
}
}