зеркало из https://github.com/mozilla/gecko-dev.git
66 строки
2.5 KiB
Rust
66 строки
2.5 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 https://mozilla.org/MPL/2.0/. */
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use crate::animate::{AnimationFieldAttrs, AnimationInputAttrs, AnimationVariantAttrs};
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use derive_common::cg;
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use proc_macro2::TokenStream;
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use quote::TokenStreamExt;
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use syn;
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use synstructure;
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pub fn derive(mut input: syn::DeriveInput) -> TokenStream {
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let animation_input_attrs = cg::parse_input_attrs::<AnimationInputAttrs>(&input);
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let no_bound = animation_input_attrs.no_bound.unwrap_or_default();
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let mut where_clause = input.generics.where_clause.take();
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for param in input.generics.type_params() {
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if !no_bound.iter().any(|name| name.is_ident(¶m.ident)) {
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cg::add_predicate(
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&mut where_clause,
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parse_quote!(#param: crate::values::animated::ToAnimatedZero),
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);
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}
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}
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let to_body = synstructure::Structure::new(&input).each_variant(|variant| {
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let attrs = cg::parse_variant_attrs_from_ast::<AnimationVariantAttrs>(&variant.ast());
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if attrs.error {
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return Some(quote! { Err(()) });
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}
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let (mapped, mapped_bindings) = cg::value(variant, "mapped");
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let bindings_pairs = variant.bindings().iter().zip(mapped_bindings);
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let mut computations = quote!();
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computations.append_all(bindings_pairs.map(|(binding, mapped_binding)| {
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let field_attrs = cg::parse_field_attrs::<AnimationFieldAttrs>(&binding.ast());
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if field_attrs.constant {
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quote! {
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let #mapped_binding = std::clone::Clone::clone(#binding);
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}
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} else {
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quote! {
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let #mapped_binding =
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crate::values::animated::ToAnimatedZero::to_animated_zero(#binding)?;
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}
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}
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}));
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computations.append_all(quote! { Ok(#mapped) });
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Some(computations)
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});
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input.generics.where_clause = where_clause;
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let name = &input.ident;
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let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
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quote! {
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impl #impl_generics crate::values::animated::ToAnimatedZero for #name #ty_generics #where_clause {
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#[allow(unused_variables)]
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#[inline]
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fn to_animated_zero(&self) -> Result<Self, ()> {
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match *self {
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#to_body
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}
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}
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}
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}
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}
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