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use proc_macro2::Span;
use proc_macro2::TokenStream;
use std::fmt::Display;
pub fn print_err(msg: String, t: TokenStream) {
println!("Error: {} in '{}'", msg, t.to_string());
}
pub fn is_python(ty: &syn::Type) -> bool {
match ty {
syn::Type::Path(ref typath) => typath
.path
.segments
.last()
.map(|seg| seg.ident == "Python")
.unwrap_or(false),
_ => false,
}
}
pub fn option_type_argument(ty: &syn::Type) -> Option<&syn::Type> {
if let syn::Type::Path(syn::TypePath { path, .. }) = ty {
let seg = path.segments.last().filter(|s| s.ident == "Option")?;
if let syn::PathArguments::AngleBracketed(params) = &seg.arguments {
if let syn::GenericArgument::Type(ty) = params.args.first()? {
return Some(ty);
}
}
}
None
}
pub fn is_text_signature_attr(attr: &syn::Attribute) -> bool {
attr.path.is_ident("text_signature")
}
fn parse_text_signature_attr<T: Display + quote::ToTokens + ?Sized>(
attr: &syn::Attribute,
python_name: &T,
) -> syn::Result<Option<syn::LitStr>> {
if !is_text_signature_attr(attr) {
return Ok(None);
}
let python_name_str = python_name.to_string();
let python_name_str = python_name_str
.rsplit('.')
.next()
.map(str::trim)
.filter(|v| !v.is_empty())
.ok_or_else(|| {
syn::Error::new_spanned(
&python_name,
format!("failed to parse python name: {}", python_name),
)
})?;
match attr.parse_meta()? {
syn::Meta::NameValue(syn::MetaNameValue {
lit: syn::Lit::Str(lit),
..
}) => {
let value = lit.value();
if value.starts_with('(') && value.ends_with(')') {
Ok(Some(syn::LitStr::new(
&(python_name_str.to_owned() + &value),
lit.span(),
)))
} else {
Err(syn::Error::new_spanned(
lit,
"text_signature must start with \"(\" and end with \")\"",
))
}
}
meta => Err(syn::Error::new_spanned(
meta,
"text_signature must be of the form #[text_signature = \"\"]",
)),
}
}
pub fn parse_text_signature_attrs<T: Display + quote::ToTokens + ?Sized>(
attrs: &mut Vec<syn::Attribute>,
python_name: &T,
) -> syn::Result<Option<syn::LitStr>> {
let mut text_signature = None;
let mut attrs_out = Vec::with_capacity(attrs.len());
for attr in attrs.drain(..) {
if let Some(value) = parse_text_signature_attr(&attr, python_name)? {
if text_signature.is_some() {
return Err(syn::Error::new_spanned(
attr,
"text_signature attribute already specified previously",
));
} else {
text_signature = Some(value);
}
} else {
attrs_out.push(attr);
}
}
*attrs = attrs_out;
Ok(text_signature)
}
pub fn get_doc(
attrs: &[syn::Attribute],
text_signature: Option<syn::LitStr>,
null_terminated: bool,
) -> syn::Result<syn::LitStr> {
let mut doc = String::new();
let mut span = Span::call_site();
if let Some(text_signature) = text_signature {
span = text_signature.span();
doc.push_str(&text_signature.value());
doc.push_str("\n--\n\n");
}
let mut separator = "";
let mut first = true;
for attr in attrs.iter() {
if let Ok(syn::Meta::NameValue(ref metanv)) = attr.parse_meta() {
if metanv.path.is_ident("doc") {
if let syn::Lit::Str(ref litstr) = metanv.lit {
if first {
first = false;
span = litstr.span();
}
let d = litstr.value();
doc.push_str(separator);
if d.starts_with(' ') {
doc.push_str(&d[1..d.len()]);
} else {
doc.push_str(&d);
};
separator = "\n";
} else {
return Err(syn::Error::new_spanned(metanv, "Invalid doc comment"));
}
}
}
}
if null_terminated {
doc.push('\0');
}
Ok(syn::LitStr::new(&doc, span))
}