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use crate::Symbol; use proc_macro2::TokenStream; use std::fmt::Display; use std::str::FromStr; use syn::punctuated::Punctuated; use syn::{ Attribute, Error, GenericArgument, Lit, Meta, PathArguments, PathSegment, Type, TypePath, }; #[inline] pub fn unwrap_punctuated_first<T, P>( punctuated: &Punctuated<T, P>, error: Error, ) -> Result<&T, Error> { match punctuated.first() { Some(s) => Ok(s), None => Err(error), } } #[inline] pub fn get_nested_type<'a>( segment: &'a PathSegment, message: &'static str, ) -> Result<&'a Type, Error> { let error = Error::new_spanned(segment, message); match &segment.arguments { PathArguments::AngleBracketed(argument) => { match unwrap_punctuated_first(&argument.args, error.clone())? { GenericArgument::Type(nested_type) => Ok(nested_type), _ => Err(error), } } _ => Err(error), } } pub fn get_nested_types<'a>( segment: &'a PathSegment, message: &'static str, ) -> Result<Vec<&'a Type>, Error> { let error = Error::new_spanned(segment, message); match &segment.arguments { PathArguments::AngleBracketed(arguments) => arguments .args .iter() .map(|argument| match argument { GenericArgument::Type(nested_type) => Ok(nested_type), _ => Err(error.clone()), }) .collect(), _ => Err(error), } } #[inline] pub fn unwrap_type_path<'a>(ty: &'a Type, message: &'static str) -> Result<&'a TypePath, Error> { match ty { Type::Path(type_path) => Ok(type_path), _ => Err(Error::new_spanned(ty, message)), } } #[inline] pub fn get_lit_str<U: Display>(lit: &Lit, ident: &U) -> Result<String, Error> { match lit { Lit::Str(lit_str) => Ok(lit_str.value()), _ => Err(Error::new_spanned( lit, format!("expected {} lit to be a string", ident), )), } } #[inline] pub fn get_lit_as_string<U: Display>(lit: &Lit, ident: &U) -> Result<String, Error> { match lit { Lit::Str(lit_str) => Ok(lit_str.value()), Lit::Int(lit_int) => Ok(lit_int.to_string()), Lit::Float(lit_float) => Ok(lit_float.to_string()), Lit::Bool(lit_bool) => Ok(lit_bool.value.to_string()), _ => Err(Error::new_spanned( lit, format!("expected {} lit to be a string/integer/float/boll", ident), )), } } #[inline] pub fn get_lit_int<T: FromStr, U: Display>(lit: &Lit, ident: &U) -> Result<T, Error> where <T as std::str::FromStr>::Err: std::fmt::Display, { match lit { Lit::Int(lit_int) => Ok(lit_int.base10_parse().unwrap()), _ => Err(Error::new_spanned( lit, format!("expected {} lit to be a integer", ident), )), } } #[inline] pub fn get_lit_float<T: FromStr, U: Display>(lit: &Lit, ident: &U) -> Result<T, Error> where <T as std::str::FromStr>::Err: std::fmt::Display, { match lit { Lit::Float(lit_float) => Ok(lit_float.base10_parse().unwrap()), _ => Err(Error::new_spanned( lit, format!("expected {} lit to be a float", ident), )), } } #[inline] pub fn get_lit_bool<U: Display>(lit: &Lit, ident: &U) -> Result<bool, Error> { match lit { Lit::Bool(lit_bool) => Ok(lit_bool.value), _ => Err(Error::new_spanned( lit, format!("expected {} lit to be a bool", ident), )), } } pub fn get_mod_path(attrs: &[Attribute]) -> Result<Option<TokenStream>, Error> { let mut mod_path = None; for attr in attrs.iter() { if attr.path == Symbol::new("mod_path") { let meta = attr.parse_meta()?; mod_path = match &meta { Meta::NameValue(mod_path_value) => { let mod_path_str = get_lit_str( &mod_path_value.lit, mod_path_value.path.get_ident().as_ref().unwrap(), )?; Some( TokenStream::from_str(mod_path_str.as_str()) .map_err(|_| Error::new_spanned(&meta, "Invalid mod_path"))?, ) } _ => None, } } } Ok(mod_path) }