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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
use crate::util::kw;
use proc_macro2::TokenStream;
use quote::{quote, ToTokens};
use syn::{
bracketed, parenthesized,
parse::{Nothing, Parse, ParseStream},
token::{Bracket, Paren},
Lit,
};
/// Default value
#[derive(Clone)]
pub enum DefaultValue {
Literal(Lit),
None(kw::None),
Some {
some: kw::Some,
paren: Paren,
inner: Box<DefaultValue>,
},
EmptySeq(Bracket),
}
impl ToTokens for DefaultValue {
fn to_tokens(&self, tokens: &mut TokenStream) {
match self {
DefaultValue::Literal(lit) => lit.to_tokens(tokens),
DefaultValue::None(kw) => kw.to_tokens(tokens),
DefaultValue::Some { inner, .. } => tokens.extend(quote! { Some(#inner) }),
DefaultValue::EmptySeq(_) => tokens.extend(quote! { [] }),
}
}
}
impl Parse for DefaultValue {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let lookahead = input.lookahead1();
if lookahead.peek(kw::None) {
let none_kw: kw::None = input.parse()?;
Ok(Self::None(none_kw))
} else if lookahead.peek(kw::Some) {
let some: kw::Some = input.parse()?;
let content;
let paren = parenthesized!(content in input);
Ok(Self::Some {
some,
paren,
inner: content.parse()?,
})
} else if lookahead.peek(Bracket) {
let content;
let bracket = bracketed!(content in input);
content.parse::<Nothing>()?;
Ok(Self::EmptySeq(bracket))
} else {
Ok(Self::Literal(input.parse()?))
}
}
}
impl DefaultValue {
fn metadata_calls(&self) -> syn::Result<TokenStream> {
match self {
DefaultValue::Literal(Lit::Int(i)) if !i.suffix().is_empty() => Err(
syn::Error::new_spanned(i, "integer literals with suffix not supported here"),
),
DefaultValue::Literal(Lit::Float(f)) if !f.suffix().is_empty() => Err(
syn::Error::new_spanned(f, "float literals with suffix not supported here"),
),
DefaultValue::Literal(Lit::Str(s)) => Ok(quote! {
.concat_value(::uniffi::metadata::codes::LIT_STR)
.concat_str(#s)
}),
DefaultValue::Literal(Lit::Int(i)) => {
let digits = i.base10_digits();
Ok(quote! {
.concat_value(::uniffi::metadata::codes::LIT_INT)
.concat_str(#digits)
})
}
DefaultValue::Literal(Lit::Float(f)) => {
let digits = f.base10_digits();
Ok(quote! {
.concat_value(::uniffi::metadata::codes::LIT_FLOAT)
.concat_str(#digits)
})
}
DefaultValue::Literal(Lit::Bool(b)) => Ok(quote! {
.concat_value(::uniffi::metadata::codes::LIT_BOOL)
.concat_bool(#b)
}),
DefaultValue::Literal(_) => Err(syn::Error::new_spanned(
self,
"this type of literal is not currently supported as a default",
)),
DefaultValue::EmptySeq(_) => Ok(quote! {
.concat_value(::uniffi::metadata::codes::LIT_EMPTY_SEQ)
}),
DefaultValue::None(_) => Ok(quote! {
.concat_value(::uniffi::metadata::codes::LIT_NONE)
}),
DefaultValue::Some { inner, .. } => {
let inner_calls = inner.metadata_calls()?;
Ok(quote! {
.concat_value(::uniffi::metadata::codes::LIT_SOME)
#inner_calls
})
}
}
}
}
pub fn default_value_metadata_calls(default: &Option<DefaultValue>) -> syn::Result<TokenStream> {
Ok(match default {
Some(default) => {
let metadata_calls = default.metadata_calls()?;
quote! {
.concat_bool(true)
#metadata_calls
}
}
None => quote! { .concat_bool(false) },
})
}