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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /servo/components/style_derive/animate.rs
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'servo/components/style_derive/animate.rs')
-rw-r--r--servo/components/style_derive/animate.rs135
1 files changed, 135 insertions, 0 deletions
diff --git a/servo/components/style_derive/animate.rs b/servo/components/style_derive/animate.rs
new file mode 100644
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+++ b/servo/components/style_derive/animate.rs
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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 https://mozilla.org/MPL/2.0/. */
+
+use darling::util::PathList;
+use derive_common::cg;
+use proc_macro2::TokenStream;
+use quote::TokenStreamExt;
+use syn::{DeriveInput, WhereClause};
+use synstructure::{Structure, VariantInfo};
+
+pub fn derive(mut input: DeriveInput) -> TokenStream {
+ let animation_input_attrs = cg::parse_input_attrs::<AnimationInputAttrs>(&input);
+
+ let no_bound = animation_input_attrs.no_bound.unwrap_or_default();
+ let mut where_clause = input.generics.where_clause.take();
+ for param in input.generics.type_params() {
+ if !no_bound.iter().any(|name| name.is_ident(&param.ident)) {
+ cg::add_predicate(
+ &mut where_clause,
+ parse_quote!(#param: crate::values::animated::Animate),
+ );
+ }
+ }
+ let (mut match_body, needs_catchall_branch) = {
+ let s = Structure::new(&input);
+ let needs_catchall_branch = s.variants().len() > 1;
+ let match_body = s.variants().iter().fold(quote!(), |body, variant| {
+ let arm = derive_variant_arm(variant, &mut where_clause);
+ quote! { #body #arm }
+ });
+ (match_body, needs_catchall_branch)
+ };
+
+ input.generics.where_clause = where_clause;
+
+ if needs_catchall_branch {
+ // This ideally shouldn't be needed, but see
+ // https://github.com/rust-lang/rust/issues/68867
+ match_body.append_all(quote! { _ => unsafe { debug_unreachable!() } });
+ }
+
+ let name = &input.ident;
+ let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+
+ quote! {
+ impl #impl_generics crate::values::animated::Animate for #name #ty_generics #where_clause {
+ #[allow(unused_variables, unused_imports)]
+ #[inline]
+ fn animate(
+ &self,
+ other: &Self,
+ procedure: crate::values::animated::Procedure,
+ ) -> Result<Self, ()> {
+ if std::mem::discriminant(self) != std::mem::discriminant(other) {
+ return Err(());
+ }
+ match (self, other) {
+ #match_body
+ }
+ }
+ }
+ }
+}
+
+fn derive_variant_arm(
+ variant: &VariantInfo,
+ where_clause: &mut Option<WhereClause>,
+) -> TokenStream {
+ let variant_attrs = cg::parse_variant_attrs_from_ast::<AnimationVariantAttrs>(&variant.ast());
+ let (this_pattern, this_info) = cg::ref_pattern(&variant, "this");
+ let (other_pattern, other_info) = cg::ref_pattern(&variant, "other");
+
+ if variant_attrs.error {
+ return quote! {
+ (&#this_pattern, &#other_pattern) => Err(()),
+ };
+ }
+
+ let (result_value, result_info) = cg::value(&variant, "result");
+ let mut computations = quote!();
+ let iter = result_info.iter().zip(this_info.iter().zip(&other_info));
+ computations.append_all(iter.map(|(result, (this, other))| {
+ let field_attrs = cg::parse_field_attrs::<AnimationFieldAttrs>(&result.ast());
+ if field_attrs.field_bound {
+ let ty = &this.ast().ty;
+ cg::add_predicate(
+ where_clause,
+ parse_quote!(#ty: crate::values::animated::Animate),
+ );
+ }
+ if field_attrs.constant {
+ quote! {
+ if #this != #other {
+ return Err(());
+ }
+ let #result = std::clone::Clone::clone(#this);
+ }
+ } else {
+ quote! {
+ let #result =
+ crate::values::animated::Animate::animate(#this, #other, procedure)?;
+ }
+ }
+ }));
+
+ quote! {
+ (&#this_pattern, &#other_pattern) => {
+ #computations
+ Ok(#result_value)
+ }
+ }
+}
+
+#[derive(Default, FromDeriveInput)]
+#[darling(attributes(animation), default)]
+pub struct AnimationInputAttrs {
+ pub no_bound: Option<PathList>,
+}
+
+#[derive(Default, FromVariant)]
+#[darling(attributes(animation), default)]
+pub struct AnimationVariantAttrs {
+ pub error: bool,
+ // Only here because of structs, where the struct definition acts as a
+ // variant itself.
+ pub no_bound: Option<PathList>,
+}
+
+#[derive(Default, FromField)]
+#[darling(attributes(animation), default)]
+pub struct AnimationFieldAttrs {
+ pub constant: bool,
+ pub field_bound: bool,
+}