servo/components/style_derive/to_animated_value.rs
2019-04-12 12:20:14 +02:00

43 lines
1.4 KiB
Rust

/* 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 https://mozilla.org/MPL/2.0/. */
use proc_macro2::TokenStream;
use syn::DeriveInput;
use synstructure::BindStyle;
use to_computed_value;
pub fn derive(input: DeriveInput) -> TokenStream {
let trait_impl = |from_body, to_body| {
quote! {
#[inline]
fn from_animated_value(animated: Self::AnimatedValue) -> Self {
match animated {
#from_body
}
}
#[inline]
fn to_animated_value(self) -> Self::AnimatedValue {
match self {
#to_body
}
}
}
};
// TODO(emilio): Consider optimizing away non-generic cases as well?
let non_generic_implementation = || None;
to_computed_value::derive_to_value(
input,
parse_quote!(crate::values::animated::ToAnimatedValue),
parse_quote!(AnimatedValue),
BindStyle::Move,
|_| false,
|binding| quote!(crate::values::animated::ToAnimatedValue::from_animated_value(#binding)),
|binding| quote!(crate::values::animated::ToAnimatedValue::to_animated_value(#binding)),
trait_impl,
non_generic_implementation,
)
}