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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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use cg;
use quote::Tokens;
use syn::{DeriveInput, Path};
use synstructure;
use to_css::CssVariantAttrs;
#[darling(attributes(parse), default)]
#[derive(Default, FromVariant)]
pub struct ParseVariantAttrs {
pub aliases: Option<String>,
pub condition: Option<Path>,
}
pub fn derive(input: DeriveInput) -> Tokens {
let name = &input.ident;
let s = synstructure::Structure::new(&input);
let mut saw_condition = false;
let match_body = s.variants().iter().fold(quote!(), |match_body, variant| {
let bindings = variant.bindings();
assert!(
bindings.is_empty(),
"Parse is only supported for single-variant enums for now"
);
let css_variant_attrs = cg::parse_variant_attrs_from_ast::<CssVariantAttrs>(&variant.ast());
let parse_attrs = cg::parse_variant_attrs_from_ast::<ParseVariantAttrs>(&variant.ast());
if css_variant_attrs.skip {
return match_body;
}
let identifier = cg::to_css_identifier(
&css_variant_attrs
.keyword
.unwrap_or(variant.ast().ident.as_ref().into()),
);
let ident = &variant.ast().ident;
saw_condition |= parse_attrs.condition.is_some();
let condition = match parse_attrs.condition {
Some(ref p) => quote! { if #p(context) },
None => quote!{},
};
let mut body = quote! {
#match_body
#identifier #condition => Ok(#name::#ident),
};
let aliases = match parse_attrs.aliases {
Some(aliases) => aliases,
None => return body,
};
for alias in aliases.split(",") {
body = quote! {
#body
#alias #condition => Ok(#name::#ident),
};
}
body
});
let context_ident = if saw_condition {
quote! { context }
} else {
quote! { _ }
};
let parse_body = if saw_condition {
quote! {
let location = input.current_source_location();
let ident = input.expect_ident()?;
match_ignore_ascii_case! { &ident,
#match_body
_ => Err(location.new_unexpected_token_error(
::cssparser::Token::Ident(ident.clone())
))
}
}
} else {
quote! { Self::parse(input) }
};
let parse_trait_impl = quote! {
impl ::parser::Parse for #name {
#[inline]
fn parse<'i, 't>(
#context_ident: &::parser::ParserContext,
input: &mut ::cssparser::Parser<'i, 't>,
) -> Result<Self, ::style_traits::ParseError<'i>> {
#parse_body
}
}
};
if saw_condition {
return parse_trait_impl;
}
// TODO(emilio): It'd be nice to get rid of these, but that makes the
// conversion harder...
let methods_impl = quote! {
impl #name {
/// Parse this keyword.
#[inline]
pub fn parse<'i, 't>(
input: &mut ::cssparser::Parser<'i, 't>,
) -> Result<Self, ::style_traits::ParseError<'i>> {
let location = input.current_source_location();
let ident = input.expect_ident()?;
Self::from_ident(ident.as_ref()).map_err(|()| {
location.new_unexpected_token_error(
::cssparser::Token::Ident(ident.clone())
)
})
}
/// Parse this keyword from a string slice.
#[inline]
pub fn from_ident(ident: &str) -> Result<Self, ()> {
match_ignore_ascii_case! { ident,
#match_body
_ => Err(()),
}
}
}
};
quote! {
#parse_trait_impl
#methods_impl
}
}
|
