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Copy pathdescrobject.rs
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266 lines (247 loc) · 8.96 KB
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use crate::PyObject;
use crate::methodobject::{PyMethodDef, build_method_def};
use crate::object::PyTypeObject;
use crate::pystate::with_vm;
use crate::util::{CStrExt, FfiPtrExt};
use core::ffi::{c_char, c_int, c_void};
use rustpython_vm::builtins::{
DescriptorMemberDef, MemberAccess, MemberKind, PyDescriptorOwned, PyGetSet, PyMappingProxy,
PyMemberDescriptor, PyMemberFlags, PyType,
};
use rustpython_vm::common::lock::PyRwLock;
use rustpython_vm::function::{ItemDoc, PySetterValue};
use rustpython_vm::{Py, PyObjectRef, PyPayload, PyRef, PyResult, VirtualMachine};
#[repr(C)]
pub struct PyGetSetDef {
pub name: *const c_char,
pub get:
Option<unsafe extern "C" fn(slf: *mut PyObject, closure: *mut c_void) -> *mut PyObject>,
pub set: Option<
unsafe extern "C" fn(
slf: *mut PyObject,
value: *mut PyObject,
closure: *mut c_void,
) -> c_int,
>,
pub doc: *const c_char,
pub closure: *mut c_void,
}
impl PyGetSetDef {
pub(crate) fn iter<'a>(mut defs: *const Self) -> impl Iterator<Item = &'a Self> {
core::iter::from_fn(move || {
let def = unsafe { &*defs };
if def.name.is_null() {
None
} else {
defs = unsafe { defs.add(1) };
Some(def)
}
})
}
pub(crate) fn build(
&self,
ty: &'static Py<PyType>,
vm: &VirtualMachine,
) -> PyResult<PyRef<PyGetSet>> {
let name = unsafe { self.name.try_as_str(vm) }?;
let closure = self.closure as usize;
let descriptor = match (self.get, self.set) {
(Some(get), Some(set)) => vm.ctx.new_static_getset(
name,
ty,
move |obj: PyObjectRef, vm: &VirtualMachine| -> PyResult<PyObjectRef> {
unsafe {
get(obj.as_raw().cast_mut(), closure as *mut c_void).assume_owned_or_err(vm)
}
},
move |obj: PyObjectRef, value: PySetterValue, vm: &VirtualMachine| unsafe {
let closure = closure as *mut c_void;
let value = value.unwrap_or_none(vm);
let result = set(obj.as_raw().cast_mut(), value.as_raw().cast_mut(), closure);
if result == 0 {
Ok(())
} else {
Err(vm.take_raised_exception().unwrap_or_else(|| {
vm.new_system_error(
"C setter returned error but did not set an exception",
)
}))
}
},
),
(Some(get), None) => vm.ctx.new_readonly_getset(
name,
ty,
move |obj: PyObjectRef, vm: &VirtualMachine| -> PyResult<PyObjectRef> {
unsafe {
get(obj.as_raw().cast_mut(), closure as *mut c_void).assume_owned_or_err(vm)
}
},
),
(None, Some(set)) => vm.ctx.new_static_getset(
name,
ty,
move |_obj: PyObjectRef, vm: &VirtualMachine| -> PyResult<PyObjectRef> {
Err(vm.new_attribute_error("unreadable attribute"))
},
move |obj: PyObjectRef, value: PySetterValue, vm: &VirtualMachine| unsafe {
let closure = closure as *mut c_void;
let value = value.unwrap_or_none(vm);
let result = set(obj.as_raw().cast_mut(), value.as_raw().cast_mut(), closure);
if result == 0 {
Ok(())
} else {
Err(vm.take_raised_exception().unwrap_or_else(|| {
vm.new_system_error(
"C setter returned error but did not set an exception",
)
}))
}
},
),
(None, None) => vm.ctx.new_readonly_getset(
name,
ty,
move |_obj: PyObjectRef, vm: &VirtualMachine| -> PyResult<PyObjectRef> {
Err(vm.new_attribute_error("unreadable attribute"))
},
),
};
Ok(descriptor)
}
}
#[repr(C)]
pub struct PyMemberDef {
pub name: *const c_char,
pub type_code: c_int,
pub offset: isize,
pub flags: c_int,
pub doc: *const c_char,
}
impl PyMemberDef {
pub(crate) fn iter<'a>(mut defs: *const Self) -> impl Iterator<Item = &'a Self> {
core::iter::from_fn(move || {
let def = unsafe { &*defs };
if def.name.is_null() {
None
} else {
defs = unsafe { defs.add(1) };
Some(def)
}
})
}
pub(crate) fn build(
&self,
ty: &Py<PyType>,
vm: &VirtualMachine,
) -> PyResult<PyRef<PyMemberDescriptor>> {
let name = unsafe { self.name.try_as_str(vm) }?;
let Some(kind) = MemberKind::from_i32(self.type_code) else {
return Err(vm.new_system_error(format!(
"PyDescr_NewMember does not support member type code {}",
self.type_code
)));
};
let mut offset = self.offset;
// Unknown bits belong to the extension and are kept.
let mut flags = PyMemberFlags::from_bits_retain(self.flags);
// Extension members never carry the internal atomic-storage bit.
flags.remove(PyMemberFlags::ATOMIC);
if flags.contains(PyMemberFlags::RELATIVE_OFFSET) {
// type creation adds tp_basicsize and clears the flag before GetOne.
// `slots.basicsize` is already the full tp_basicsize.
offset += ty.slots.basicsize as isize;
flags.remove(PyMemberFlags::RELATIVE_OFFSET);
}
let doc = unsafe { self.doc.try_as_str_opt(vm) }?.map_or(ItemDoc::NONE, |doc| {
let text: &'static str = Box::leak(doc.to_owned().into_boxed_str());
ItemDoc::static_text(text)
});
let descriptor = PyMemberDescriptor {
common: PyDescriptorOwned {
typ: ty.to_owned(),
name: vm.ctx.intern_str(name),
qualname: PyRwLock::new(None),
},
member: DescriptorMemberDef {
name: name.to_owned(),
kind,
offset,
flags,
doc,
},
// `offset` is a byte offset from the object to the field.
access: MemberAccess::Offset,
};
Ok(descriptor.into_ref(&vm.ctx))
}
}
#[unsafe(no_mangle)]
pub unsafe extern "C" fn PyDictProxy_New(mapping: *mut PyObject) -> *mut PyObject {
with_vm(|vm| {
let mapping = unsafe { mapping.assume_borrowed() }.to_owned();
Ok(PyMappingProxy::from_object(mapping, vm)?.into_ref(&vm.ctx))
})
}
#[unsafe(no_mangle)]
pub unsafe extern "C" fn PyDescr_NewMethod(
typ: *mut PyTypeObject,
method: *mut PyMethodDef,
) -> *mut PyObject {
with_vm(|vm| {
let method = build_method_def(vm, unsafe { &*method }, true)?;
Ok(method.build_method(unsafe { typ.assume_borrowed() }, vm))
})
}
#[unsafe(no_mangle)]
pub unsafe extern "C" fn PyDescr_NewClassMethod(
typ: *mut PyTypeObject,
method: *mut PyMethodDef,
) -> *mut PyObject {
with_vm(|vm| {
let method = build_method_def(vm, unsafe { &*method }, true)?;
Ok(method.build_method(unsafe { typ.assume_borrowed() }, vm))
})
}
#[unsafe(no_mangle)]
pub unsafe extern "C" fn PyDescr_NewGetSet(
typ: *mut PyTypeObject,
getset: *mut PyGetSetDef,
) -> *mut PyObject {
with_vm(|vm| unsafe { &*getset }.build(unsafe { typ.assume_borrowed() }, vm))
}
#[unsafe(no_mangle)]
pub unsafe extern "C" fn PyDescr_NewMember(
typ: *mut PyTypeObject,
member: *mut PyMemberDef,
) -> *mut PyObject {
with_vm(|vm| Ok(unsafe { &*member }.build(unsafe { typ.assume_borrowed() }, vm)))
}
#[unsafe(no_mangle)]
pub unsafe extern "C" fn PyWrapper_New(descr: *mut PyObject, obj: *mut PyObject) -> *mut PyObject {
with_vm(|vm| {
let descr = unsafe { descr.assume_borrowed() };
let obj = unsafe { obj.assume_borrowed() };
vm.call_special_method(
descr,
vm.ctx.names.__get__,
(obj.to_owned(), obj.class().to_owned()),
)
})
}
#[cfg(test)]
mod tests {
use pyo3::prelude::*;
use pyo3::types::{PyDict, PyInt, PyMappingProxy};
#[test]
fn proxy_reads_items() {
Python::attach(|py| {
let dict = PyDict::new(py);
dict.set_item("x", 7).unwrap();
let mapping = dict.as_mapping();
let proxy = PyMappingProxy::new(py, mapping);
let value = proxy.get_item("x").unwrap().cast_into::<PyInt>().unwrap();
assert_eq!(value, 7);
})
}
}