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08b5d999f0
This is a sub-PR of #19015 r? emilio --- - [x] `./mach build -d` does not report any errors - [x] `./mach test-tidy` does not report any errors - [x] These changes fix #19582 - [x] These changes do not require tests Source-Repo: https://github.com/servo/servo Source-Revision: 8aba41d951d63a09cc6c12cba7ed200ea4396544 --HG-- extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear extra : subtree_revision : 24b27ac8fd2e837f365610ecd737993588b6ea98
121 lines
3.6 KiB
Rust
121 lines
3.6 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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use cg;
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use quote::Tokens;
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use syn::DeriveInput;
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use synstructure;
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pub fn derive(input: DeriveInput) -> Tokens {
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let name = &input.ident;
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let trait_path = &["style_traits", "ToCss"];
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let (impl_generics, ty_generics, mut where_clause) =
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cg::trait_parts(&input, trait_path);
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let input_attrs = cg::parse_input_attrs::<CssInputAttrs>(&input);
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let style = synstructure::BindStyle::Ref.into();
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let match_body = synstructure::each_variant(&input, &style, |bindings, variant| {
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let mut identifier = cg::to_css_identifier(variant.ident.as_ref());
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let variant_attrs = cg::parse_variant_attrs::<CssVariantAttrs>(variant);
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let separator = if variant_attrs.comma { ", " } else { " " };
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if variant_attrs.dimension {
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assert_eq!(bindings.len(), 1);
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assert!(!variant_attrs.function, "That makes no sense");
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}
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let mut expr = if !bindings.is_empty() {
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let mut expr = quote! {};
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if variant_attrs.iterable {
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assert_eq!(bindings.len(), 1);
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let binding = &bindings[0];
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expr = quote! {
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#expr
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for item in #binding.iter() {
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writer.item(item)?;
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}
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};
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} else {
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for binding in bindings {
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where_clause.add_trait_bound(&binding.field.ty);
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expr = quote! {
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#expr
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writer.item(#binding)?;
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};
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}
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}
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quote! {{
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let mut writer = ::style_traits::values::SequenceWriter::new(&mut *dest, #separator);
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#expr
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Ok(())
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}}
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} else {
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quote! {
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::std::fmt::Write::write_str(dest, #identifier)
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}
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};
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if variant_attrs.dimension {
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expr = quote! {
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#expr?;
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::std::fmt::Write::write_str(dest, #identifier)
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}
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} else if variant_attrs.function {
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identifier.push_str("(");
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expr = quote! {
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::std::fmt::Write::write_str(dest, #identifier)?;
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#expr?;
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::std::fmt::Write::write_str(dest, ")")
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}
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}
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Some(expr)
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});
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let mut impls = quote! {
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impl #impl_generics ::style_traits::ToCss for #name #ty_generics #where_clause {
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#[allow(unused_variables)]
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#[inline]
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fn to_css<W>(&self, dest: &mut W) -> ::std::fmt::Result
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where
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W: ::std::fmt::Write
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{
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match *self {
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#match_body
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}
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}
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}
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};
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if input_attrs.derive_debug {
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impls.append(quote! {
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impl #impl_generics ::std::fmt::Debug for #name #ty_generics #where_clause {
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fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
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::style_traits::ToCss::to_css(self, f)
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}
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}
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});
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}
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impls
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}
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#[darling(attributes(css), default)]
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#[derive(Default, FromDeriveInput)]
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struct CssInputAttrs {
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derive_debug: bool,
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function: bool,
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comma: bool,
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}
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#[darling(attributes(css), default)]
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#[derive(Default, FromVariant)]
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struct CssVariantAttrs {
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function: bool,
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iterable: bool,
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comma: bool,
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dimension: bool,
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}
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