pyo3/pyo3-derive-backend/src/method.rs

552 lines
19 KiB
Rust

// Copyright (c) 2017-present PyO3 Project and Contributors
use crate::pyfunction::Argument;
use crate::pyfunction::{parse_name_attribute, PyFunctionAttr};
use crate::utils;
use proc_macro2::TokenStream;
use quote::quote;
use quote::ToTokens;
use syn::ext::IdentExt;
use syn::spanned::Spanned;
#[derive(Clone, PartialEq, Debug)]
pub struct FnArg<'a> {
pub name: &'a syn::Ident,
pub by_ref: &'a Option<syn::token::Ref>,
pub mutability: &'a Option<syn::token::Mut>,
pub ty: &'a syn::Type,
pub optional: Option<&'a syn::Type>,
pub py: bool,
pub reference: bool,
}
#[derive(Clone, PartialEq, Debug)]
pub enum FnType {
Getter,
Setter,
Fn,
FnNew,
FnCall,
FnClass,
FnStatic,
PySelf(syn::TypeReference),
}
#[derive(Clone, PartialEq, Debug)]
pub struct FnSpec<'a> {
pub tp: FnType,
// Rust function name
pub name: &'a syn::Ident,
// Wrapped python name. This should not have any leading r#.
// r# can be removed by syn::ext::IdentExt::unraw()
pub python_name: syn::Ident,
pub attrs: Vec<Argument>,
pub args: Vec<FnArg<'a>>,
pub output: syn::Type,
pub doc: syn::LitStr,
}
pub fn get_return_info(output: &syn::ReturnType) -> syn::Type {
match output {
syn::ReturnType::Default => syn::Type::Infer(syn::parse_quote! {_}),
syn::ReturnType::Type(_, ref ty) => *ty.clone(),
}
}
impl<'a> FnSpec<'a> {
/// Parser function signature and function attributes
pub fn parse(
sig: &'a syn::Signature,
meth_attrs: &mut Vec<syn::Attribute>,
allow_custom_name: bool,
) -> syn::Result<FnSpec<'a>> {
let name = &sig.ident;
let MethodAttributes {
ty: mut fn_type,
args: fn_attrs,
mut python_name,
} = parse_method_attributes(meth_attrs, allow_custom_name)?;
let mut has_self = false;
let mut arguments = Vec::new();
for input in sig.inputs.iter() {
match input {
syn::FnArg::Receiver(_) => {
has_self = true;
}
syn::FnArg::Typed(syn::PatType {
ref pat, ref ty, ..
}) => {
// skip first argument (cls)
if fn_type == FnType::FnClass && !has_self {
has_self = true;
continue;
}
let (ident, by_ref, mutability) = match **pat {
syn::Pat::Ident(syn::PatIdent {
ref ident,
ref by_ref,
ref mutability,
..
}) => (ident, by_ref, mutability),
_ => {
return Err(syn::Error::new_spanned(pat, "unsupported argument"));
}
};
let py = crate::utils::if_type_is_python(ty);
let opt = check_arg_ty_and_optional(name, ty);
arguments.push(FnArg {
name: ident,
by_ref,
mutability,
// mode: mode,
ty,
optional: opt,
py,
reference: is_ref(name, ty),
});
}
}
}
let ty = get_return_info(&sig.output);
if fn_type == FnType::Fn && !has_self {
if arguments.is_empty() {
return Err(syn::Error::new_spanned(
name,
"Static method needs #[staticmethod] attribute",
));
}
let tp = match arguments.remove(0).ty {
syn::Type::Reference(r) => replace_self(r)?,
x => return Err(syn::Error::new_spanned(x, "Invalid type as custom self")),
};
fn_type = FnType::PySelf(tp);
}
// "Tweak" getter / setter names: strip off set_ and get_ if needed
if let FnType::Getter | FnType::Setter = &fn_type {
if python_name.is_none() {
let prefix = match &fn_type {
FnType::Getter => "get_",
FnType::Setter => "set_",
_ => unreachable!(),
};
let ident = sig.ident.unraw().to_string();
if ident.starts_with(prefix) {
python_name = Some(syn::Ident::new(&ident[prefix.len()..], ident.span()))
}
}
}
let python_name = python_name.unwrap_or_else(|| name.unraw());
let mut parse_erroneous_text_signature = |error_msg: &str| {
// try to parse anyway to give better error messages
if let Some(text_signature) =
utils::parse_text_signature_attrs(meth_attrs, &python_name)?
{
Err(syn::Error::new_spanned(text_signature, error_msg))
} else {
Ok(None)
}
};
let text_signature = match &fn_type {
FnType::Fn | FnType::PySelf(_) | FnType::FnClass | FnType::FnStatic => {
utils::parse_text_signature_attrs(&mut *meth_attrs, name)?
}
FnType::FnNew => parse_erroneous_text_signature(
"text_signature not allowed on __new__; if you want to add a signature on \
__new__, put it on the struct definition instead",
)?,
FnType::FnCall | FnType::Getter | FnType::Setter => {
parse_erroneous_text_signature("text_signature not allowed with this attribute")?
}
};
let doc = utils::get_doc(&meth_attrs, text_signature, true)?;
Ok(FnSpec {
tp: fn_type,
name,
python_name,
attrs: fn_attrs,
args: arguments,
output: ty,
doc,
})
}
pub fn is_args(&self, name: &syn::Ident) -> bool {
for s in self.attrs.iter() {
if let Argument::VarArgs(ref path) = s {
return path.is_ident(name);
}
}
false
}
pub fn accept_args(&self) -> bool {
for s in self.attrs.iter() {
match *s {
Argument::VarArgs(_) => return true,
Argument::VarArgsSeparator => return true,
_ => (),
}
}
false
}
pub fn is_kwargs(&self, name: &syn::Ident) -> bool {
for s in self.attrs.iter() {
if let Argument::KeywordArgs(ref path) = s {
return path.is_ident(name);
}
}
false
}
pub fn accept_kwargs(&self) -> bool {
for s in self.attrs.iter() {
if let Argument::KeywordArgs(_) = s {
return true;
}
}
false
}
pub fn default_value(&self, name: &syn::Ident) -> Option<TokenStream> {
for s in self.attrs.iter() {
match *s {
Argument::Arg(ref path, ref opt) => {
if path.is_ident(name) {
if let Some(ref val) = opt {
let i: syn::Expr = syn::parse_str(&val).unwrap();
return Some(i.into_token_stream());
}
}
}
Argument::Kwarg(ref path, ref opt) => {
if path.is_ident(name) {
let i: syn::Expr = syn::parse_str(&opt).unwrap();
return Some(quote!(#i));
}
}
_ => (),
}
}
None
}
pub fn is_kw_only(&self, name: &syn::Ident) -> bool {
for s in self.attrs.iter() {
if let Argument::Kwarg(ref path, _) = s {
if path.is_ident(name) {
return true;
}
}
}
false
}
}
pub fn is_ref(name: &syn::Ident, ty: &syn::Type) -> bool {
match ty {
syn::Type::Reference(_) => return true,
syn::Type::Path(syn::TypePath { ref path, .. }) => {
if let Some(segment) = path.segments.last() {
if "Option" == segment.ident.to_string().as_str() {
match segment.arguments {
syn::PathArguments::AngleBracketed(ref params) => {
if params.args.len() != 1 {
panic!("argument type is not supported by python method: {:?} ({:?}) {:?}",
name,
ty,
path);
}
let last = &params.args[params.args.len() - 1];
if let syn::GenericArgument::Type(syn::Type::Reference(_)) = last {
return true;
}
}
_ => {
panic!(
"argument type is not supported by python method: {:?} ({:?}) {:?}",
name, ty, path
);
}
}
}
}
}
_ => (),
}
false
}
pub fn check_arg_ty_and_optional<'a>(
name: &'a syn::Ident,
ty: &'a syn::Type,
) -> Option<&'a syn::Type> {
match ty {
syn::Type::Path(syn::TypePath { ref path, .. }) => {
//if let Some(ref qs) = qs {
// panic!("explicit Self type in a 'qualified path' is not supported: {:?} - {:?}",
// name, qs);
//}
if let Some(segment) = path.segments.last() {
match segment.ident.to_string().as_str() {
"Option" => match segment.arguments {
syn::PathArguments::AngleBracketed(ref params) => {
if params.args.len() != 1 {
panic!("argument type is not supported by python method: {:?} ({:?}) {:?}",
name,
ty,
path);
}
match &params.args[0] {
syn::GenericArgument::Type(ref ty) => Some(ty),
_ => panic!("argument type is not supported by python method: {:?} ({:?}) {:?}",
name,
ty,
path),
}
}
_ => {
panic!(
"argument type is not supported by python method: {:?} ({:?}) {:?}",
name, ty, path
);
}
},
_ => None,
}
} else {
None
}
}
_ => {
None
//panic!("argument type is not supported by python method: {:?} ({:?})",
//name,
//ty);
}
}
}
#[derive(Clone, PartialEq, Debug)]
struct MethodAttributes {
ty: FnType,
args: Vec<Argument>,
python_name: Option<syn::Ident>,
}
fn parse_method_attributes(
attrs: &mut Vec<syn::Attribute>,
allow_custom_name: bool,
) -> syn::Result<MethodAttributes> {
let mut new_attrs = Vec::new();
let mut args = Vec::new();
let mut res: Option<FnType> = None;
let mut property_name = None;
for attr in attrs.iter() {
match attr.parse_meta()? {
syn::Meta::Path(ref name) => {
if name.is_ident("new") || name.is_ident("__new__") {
res = Some(FnType::FnNew)
} else if name.is_ident("init") || name.is_ident("__init__") {
return Err(syn::Error::new_spanned(
name,
"#[init] is disabled from PyO3 0.9.0",
));
} else if name.is_ident("call") || name.is_ident("__call__") {
res = Some(FnType::FnCall)
} else if name.is_ident("classmethod") {
res = Some(FnType::FnClass)
} else if name.is_ident("staticmethod") {
res = Some(FnType::FnStatic)
} else if name.is_ident("setter") || name.is_ident("getter") {
if let syn::AttrStyle::Inner(_) = attr.style {
return Err(syn::Error::new_spanned(
attr,
"Inner style attribute is not supported for setter and getter",
));
}
if res != None {
return Err(syn::Error::new_spanned(
attr,
"setter/getter attribute can not be used mutiple times",
));
}
if name.is_ident("setter") {
res = Some(FnType::Setter)
} else {
res = Some(FnType::Getter)
}
} else {
new_attrs.push(attr.clone())
}
}
syn::Meta::List(syn::MetaList {
ref path,
ref nested,
..
}) => {
if path.is_ident("new") {
res = Some(FnType::FnNew)
} else if path.is_ident("init") {
return Err(syn::Error::new_spanned(
path,
"#[init] is disabled from PyO3 0.9.0",
));
} else if path.is_ident("call") {
res = Some(FnType::FnCall)
} else if path.is_ident("setter") || path.is_ident("getter") {
if let syn::AttrStyle::Inner(_) = attr.style {
return Err(syn::Error::new_spanned(
attr,
"Inner style attribute is not supported for setter and getter",
));
}
if res != None {
return Err(syn::Error::new_spanned(
attr,
"setter/getter attribute can not be used mutiple times",
));
}
if nested.len() != 1 {
return Err(syn::Error::new_spanned(
attr,
"setter/getter requires one value",
));
}
res = if path.is_ident("setter") {
Some(FnType::Setter)
} else {
Some(FnType::Getter)
};
property_name = match nested.first().unwrap() {
syn::NestedMeta::Meta(syn::Meta::Path(ref w)) if w.segments.len() == 1 => {
Some(w.segments[0].ident.clone())
}
syn::NestedMeta::Lit(ref lit) => match *lit {
syn::Lit::Str(ref s) => Some(s.parse()?),
_ => {
return Err(syn::Error::new_spanned(
lit,
"setter/getter attribute requires str value",
))
}
},
_ => {
return Err(syn::Error::new_spanned(
nested.first().unwrap(),
"expected ident or string literal for property name",
))
}
};
} else if path.is_ident("args") {
let attrs = PyFunctionAttr::from_meta(nested)?;
args.extend(attrs.arguments)
} else {
new_attrs.push(attr.clone())
}
}
syn::Meta::NameValue(_) => new_attrs.push(attr.clone()),
}
}
attrs.clear();
attrs.extend(new_attrs);
let ty = res.unwrap_or(FnType::Fn);
let python_name = if allow_custom_name {
parse_method_name_attribute(&ty, attrs, property_name)?
} else {
property_name
};
Ok(MethodAttributes {
ty,
args,
python_name,
})
}
fn parse_method_name_attribute(
ty: &FnType,
attrs: &mut Vec<syn::Attribute>,
property_name: Option<syn::Ident>,
) -> syn::Result<Option<syn::Ident>> {
let name = parse_name_attribute(attrs)?;
// Reject some invalid combinations
if let Some(name) = &name {
match ty {
FnType::FnNew | FnType::FnCall | FnType::Getter | FnType::Setter => {
return Err(syn::Error::new_spanned(
name,
"name not allowed with this attribute",
))
}
_ => {}
}
}
// Thanks to check above we can be sure that this generates the right python name
Ok(match ty {
FnType::FnNew => Some(syn::Ident::new("__new__", proc_macro2::Span::call_site())),
FnType::FnCall => Some(syn::Ident::new("__call__", proc_macro2::Span::call_site())),
FnType::Getter | FnType::Setter => property_name,
_ => name,
})
}
// Replace &A<Self> with &A<_>
fn replace_self(refn: &syn::TypeReference) -> syn::Result<syn::TypeReference> {
fn infer(span: proc_macro2::Span) -> syn::GenericArgument {
syn::GenericArgument::Type(syn::Type::Infer(syn::TypeInfer {
underscore_token: syn::token::Underscore { spans: [span] },
}))
}
let mut res = refn.to_owned();
let tp = match &mut *res.elem {
syn::Type::Path(p) => p,
_ => return Err(syn::Error::new_spanned(refn, "unsupported argument")),
};
for seg in &mut tp.path.segments {
if let syn::PathArguments::AngleBracketed(ref mut g) = seg.arguments {
let mut args = syn::punctuated::Punctuated::new();
for arg in &g.args {
let mut add_arg = true;
if let syn::GenericArgument::Lifetime(_) = arg {
add_arg = false;
}
if let syn::GenericArgument::Type(syn::Type::Path(p)) = arg {
if p.path.segments.len() == 1 && p.path.segments[0].ident == "Self" {
args.push(infer(p.span()));
add_arg = false;
}
}
if add_arg {
args.push(arg.clone());
}
}
g.args = args;
}
}
res.lifetime = None;
Ok(res)
}