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pyproto.rs
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pyproto.rs
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// Copyright (c) 2017-present PyO3 Project and Contributors
use crate::defs;
use crate::method::{FnSpec, FnType};
use crate::proto_method::impl_method_proto;
use crate::pyfunction::PyFunctionOptions;
use crate::pymethod;
use proc_macro2::{Span, TokenStream};
use quote::quote;
use quote::ToTokens;
use std::collections::HashSet;
use syn::spanned::Spanned;
pub fn build_py_proto(ast: &mut syn::ItemImpl) -> syn::Result<TokenStream> {
let (path, proto) = if let Some((_, path, _)) = &mut ast.trait_ {
let proto = match path.segments.last() {
Some(segment) if segment.ident == "PyObjectProtocol" => &defs::OBJECT,
Some(segment) if segment.ident == "PyAsyncProtocol" => &defs::ASYNC,
Some(segment) if segment.ident == "PyMappingProtocol" => &defs::MAPPING,
Some(segment) if segment.ident == "PyIterProtocol" => &defs::ITER,
Some(segment) if segment.ident == "PySequenceProtocol" => &defs::SEQ,
Some(segment) if segment.ident == "PyNumberProtocol" => &defs::NUM,
Some(segment) if segment.ident == "PyDescrProtocol" => &defs::DESCR,
Some(segment) if segment.ident == "PyBufferProtocol" => &defs::BUFFER,
Some(segment) if segment.ident == "PyGCProtocol" => &defs::GC,
_ => bail_spanned!(path.span() => "unrecognised trait for #[pyproto]"),
};
(path, proto)
} else {
bail_spanned!(
ast.span() => "#[pyproto] can only be used with protocol trait implementations"
);
};
let tokens = impl_proto_impl(&ast.self_ty, &mut ast.items, proto)?;
// attach lifetime
let mut seg = path.segments.pop().unwrap().into_value();
seg.arguments = syn::PathArguments::AngleBracketed(syn::parse_quote! {<'p>});
path.segments.push(seg);
ast.generics.params = syn::parse_quote! {'p};
Ok(tokens)
}
fn impl_proto_impl(
ty: &syn::Type,
impls: &mut [syn::ImplItem],
proto: &defs::Proto,
) -> syn::Result<TokenStream> {
let mut trait_impls = TokenStream::new();
let mut py_methods = Vec::new();
let mut method_names = HashSet::new();
let module = proto.module();
for iimpl in impls.iter_mut() {
if let syn::ImplItem::Method(met) = iimpl {
// impl Py~Protocol<'p> { type = ... }
if let Some(m) = proto.get_proto(&met.sig.ident) {
impl_method_proto(ty, &mut met.sig, &module, m)?.to_tokens(&mut trait_impls);
// Insert the method to the HashSet
method_names.insert(met.sig.ident.to_string());
}
// Add non-slot methods to inventory like `#[pymethods]`
if let Some(m) = proto.get_method(&met.sig.ident) {
let fn_spec =
FnSpec::parse(&mut met.sig, &mut met.attrs, PyFunctionOptions::default())?;
let flags = if m.can_coexist {
// We need METH_COEXIST here to prevent __add__ from overriding __radd__
Some(quote!(_pyo3::ffi::METH_COEXIST))
} else {
None
};
let method = if let FnType::Fn(_) = &fn_spec.tp {
pymethod::impl_py_method_def(ty, &fn_spec, flags)?
} else {
bail_spanned!(
met.sig.span() => "expected method with receiver for #[pyproto] method"
);
};
py_methods.push(method);
}
}
}
let items = impl_proto_items(method_names, py_methods, ty, proto);
Ok(quote! {
const _: () = {
use ::pyo3 as _pyo3; // pyproto doesn't support specifying #[pyo3(crate)]
#trait_impls
#items
};
})
}
fn impl_proto_items(
method_names: HashSet<String>,
py_methods: Vec<TokenStream>,
ty: &syn::Type,
proto: &defs::Proto,
) -> TokenStream {
if method_names.is_empty() && py_methods.is_empty() {
return TokenStream::default();
}
let module = proto.module();
let items_trait = proto.items_trait();
let items_trait_items = proto.items_trait_items();
let mut tokens = proto
.slot_defs(method_names)
.map(|def| {
let slot = syn::Ident::new(def.slot, Span::call_site());
let slot_impl = syn::Ident::new(def.slot_impl, Span::call_site());
quote! {{
_pyo3::ffi::PyType_Slot {
slot: _pyo3::ffi::#slot,
pfunc: #module::#slot_impl::<#ty> as _
}
}}
})
.peekable();
if tokens.peek().is_none() {
return TokenStream::default();
}
quote! {
impl _pyo3::impl_::pyclass::#items_trait<#ty>
for _pyo3::impl_::pyclass::PyClassImplCollector<#ty>
{
fn #items_trait_items(self) -> &'static _pyo3::impl_::pyclass::PyClassItems {
static ITEMS: _pyo3::impl_::pyclass::PyClassItems = _pyo3::impl_::pyclass::PyClassItems {
methods: &[#(#py_methods),*],
slots: &[#(#tokens),*]
};
&ITEMS
}
}
}
}