tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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to_animated_zero.rs (2579B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this
      3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
      4 
      5 use crate::animate::{AnimationFieldAttrs, AnimationInputAttrs, AnimationVariantAttrs};
      6 use crate::cg;
      7 use proc_macro2::TokenStream;
      8 use quote::TokenStreamExt;
      9 use syn;
     10 use synstructure;
     11 
     12 pub fn derive(mut input: syn::DeriveInput) -> TokenStream {
     13    let animation_input_attrs = cg::parse_input_attrs::<AnimationInputAttrs>(&input);
     14    let no_bound = animation_input_attrs.no_bound.unwrap_or_default();
     15    let mut where_clause = input.generics.where_clause.take();
     16    for param in input.generics.type_params() {
     17        if !no_bound.iter().any(|name| name.is_ident(&param.ident)) {
     18            cg::add_predicate(
     19                &mut where_clause,
     20                parse_quote!(#param: crate::values::animated::ToAnimatedZero),
     21            );
     22        }
     23    }
     24 
     25    let to_body = synstructure::Structure::new(&input).each_variant(|variant| {
     26        let attrs = cg::parse_variant_attrs_from_ast::<AnimationVariantAttrs>(&variant.ast());
     27        if attrs.error {
     28            return Some(quote! { Err(()) });
     29        }
     30        let (mapped, mapped_bindings) = cg::value(variant, "mapped");
     31        let bindings_pairs = variant.bindings().iter().zip(mapped_bindings);
     32        let mut computations = quote!();
     33        computations.append_all(bindings_pairs.map(|(binding, mapped_binding)| {
     34            let field_attrs = cg::parse_field_attrs::<AnimationFieldAttrs>(&binding.ast());
     35            if field_attrs.constant {
     36                quote! {
     37                    let #mapped_binding = std::clone::Clone::clone(#binding);
     38                }
     39            } else {
     40                quote! {
     41                    let #mapped_binding =
     42                        crate::values::animated::ToAnimatedZero::to_animated_zero(#binding)?;
     43                }
     44            }
     45        }));
     46        computations.append_all(quote! { Ok(#mapped) });
     47        Some(computations)
     48    });
     49    input.generics.where_clause = where_clause;
     50 
     51    let name = &input.ident;
     52    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
     53 
     54    quote! {
     55        impl #impl_generics crate::values::animated::ToAnimatedZero for #name #ty_generics #where_clause {
     56            #[allow(unused_variables)]
     57            #[inline]
     58            fn to_animated_zero(&self) -> Result<Self, ()> {
     59                match *self {
     60                    #to_body
     61                }
     62            }
     63        }
     64    }
     65 }