feat: Add IntoOwned trait (parcel-bundler#597)

Author: kdy1

derive/src/into_owned.rs

@@ -2,15 +2,15 @@ use proc_macro::{self, TokenStream};
 use proc_macro2::Span;
 use quote::quote;
 use syn::{
-  parse_macro_input, Data, DataEnum, DeriveInput, Field, Fields, GenericArgument, Ident, Member, PathArguments,
-  Type,
+  parse_macro_input, parse_quote, Data, DataEnum, DeriveInput, Field, Fields, GenericArgument, Ident, Member,
+  PathArguments, Type,
 };
 
 pub(crate) fn derive_into_owned(input: TokenStream) -> TokenStream {
   let DeriveInput {
     ident: self_name,
     data,
-    generics,
+    mut generics,
     ..
   } = parse_macro_input!(input);
 
@@ -105,16 +105,61 @@ pub(crate) fn derive_into_owned(input: TokenStream) -> TokenStream {
     }
   };
 
-  let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
+  let orig_generics = generics.clone();
 
-  let into_owned = if generics.lifetimes().next().is_none() {
-    panic!("can't derive IntoOwned on a type without any lifetimes")
+  // Add generic bounds for all type parameters.
+  let mut type_param_names = vec![];
+
+  for ty in generics.type_params() {
+    type_param_names.push(ty.ident.clone());
+  }
+
+  for type_param in type_param_names {
+    generics.make_where_clause().predicates.push_value(parse_quote! {
+      #type_param: 'static + for<'aa> crate::traits::IntoOwned<'aa>
+    })
+  }
+
+  let has_lifetime = generics
+    .params
+    .first()
+    .map_or(false, |v| matches!(v, syn::GenericParam::Lifetime(..)));
+
+  // Prepend `'any` to generics
+  let any = syn::GenericParam::Lifetime(syn::LifetimeDef {
+    attrs: Default::default(),
+    lifetime: syn::Lifetime {
+      apostrophe: Span::call_site(),
+      ident: Ident::new("any", Span::call_site()),
+    },
+    colon_token: None,
+    bounds: Default::default(),
+  });
+  generics.params.insert(0, any.clone());
+
+  let (impl_generics, _, where_clause) = generics.split_for_impl();
+  let (_, ty_generics, _) = orig_generics.split_for_impl();
+
+  let into_owned = if !has_lifetime {
+    quote! {
+      impl #impl_generics crate::traits::IntoOwned<'any> for #self_name #ty_generics #where_clause {
+        type Owned = Self;
+
+        #[inline]
+        fn into_owned(self) -> Self {
+          self
+        }
+      }
+    }
   } else {
     let params = generics.type_params();
     quote! {
-      impl #impl_generics #self_name #ty_generics #where_clause {
+      impl #impl_generics crate::traits::IntoOwned<'any> for #self_name #ty_generics #where_clause {
+        type Owned = #self_name<'any, #(#params),*>;
         /// Consumes the value and returns an owned clone.
-        pub fn into_owned<'x>(self) -> #self_name<'x, #(#params),*> {
+        fn into_owned(self) -> Self::Owned {
+          use crate::traits::IntoOwned;
+
           #res
         }
       }

node/src/transformer.rs

@@ -3,6 +3,7 @@ use std::{
   ops::{Index, IndexMut},
 };
 
+use lightningcss::traits::IntoOwned;
 use lightningcss::{
   media_query::MediaFeatureValue,
   properties::{

src/error.rs

@@ -2,6 +2,8 @@
 
 use crate::properties::custom::Token;
 use crate::rules::Location;
+#[cfg(feature = "into_owned")]
+use crate::traits::IntoOwned;
 use crate::values::string::CowArcStr;
 use cssparser::{BasicParseErrorKind, ParseError, ParseErrorKind};
 use parcel_selectors::parser::SelectorParseErrorKind;

src/media_query.rs

@@ -1,5 +1,4 @@
 //! Media queries.
-
 use crate::error::{ErrorWithLocation, MinifyError, MinifyErrorKind, ParserError, PrinterError};
 use crate::macros::enum_property;
 use crate::parser::starts_with_ignore_ascii_case;
@@ -11,6 +10,8 @@ use crate::rules::custom_media::CustomMediaRule;
 use crate::rules::Location;
 use crate::stylesheet::ParserOptions;
 use crate::targets::{should_compile, Targets};
+#[cfg(feature = "into_owned")]
+use crate::traits::IntoOwned;
 use crate::traits::{Parse, ToCss};
 use crate::values::ident::{DashedIdent, Ident};
 use crate::values::number::{CSSInteger, CSSNumber};
@@ -1257,6 +1258,7 @@ macro_rules! define_query_features {
 pub(crate) use define_query_features;
 
 define_query_features! {
+  #[cfg_attr(feature = "into_owned", derive(lightningcss_derive::IntoOwned))]
   /// A media query feature identifier.
   pub enum MediaFeatureId {
     /// The [width](https://w3c.github.io/csswg-drafts/mediaqueries-5/#width) media feature.

src/properties/custom.rs

@@ -180,6 +180,7 @@ impl<'i> UnparsedProperty<'i> {
   ) -> Result<super::Property<'x>, ()> {
     use super::Property;
     use crate::stylesheet::PrinterOptions;
+    use crate::traits::IntoOwned;
 
     // Substitute variables in the token list.
     self.value.substitute_variables(vars);

src/properties/mod.rs

@@ -128,6 +128,8 @@ use crate::parser::ParserOptions;
 use crate::prefixes::Feature;
 use crate::printer::{Printer, PrinterOptions};
 use crate::targets::Targets;
+#[cfg(feature = "into_owned")]
+use crate::traits::IntoOwned;
 use crate::traits::{Parse, ParseWithOptions, Shorthand, ToCss};
 use crate::values::number::{CSSInteger, CSSNumber};
 use crate::values::string::CowArcStr;

src/rules/container.rs

@@ -74,6 +74,7 @@ pub type ContainerSizeFeature<'i> = QueryFeature<'i, ContainerSizeFeatureId>;
 
 define_query_features! {
   /// A container query size feature identifier.
+  #[cfg_attr(feature = "into_owned", derive(lightningcss_derive::IntoOwned))]
   pub enum ContainerSizeFeatureId {
     /// The [width](https://w3c.github.io/csswg-drafts/css-contain-3/#width) size container feature.
     "width": Width = Length,

src/traits.rs

@@ -10,6 +10,38 @@ use crate::targets::{Browsers, Targets};
 use crate::vendor_prefix::VendorPrefix;
 use cssparser::*;
 
+/// A trait for things that can be cloned with a new lifetime.
+///
+/// `'any` lifeitme means the output should have `'static` lifetime.
+#[cfg(feature = "into_owned")]
+pub trait IntoOwned<'any> {
+  /// A variant of `Self` with a new lifetime.
+  type Owned: 'any;
+
+  /// Make lifetime of `self` `'static`.
+  fn into_owned(self) -> Self::Owned;
+}
+
+#[cfg(feature = "into_owned")]
+macro_rules! impl_into_owned {
+  ($t: ty) => {
+    impl<'a> IntoOwned<'a> for $t {
+      type Owned = Self;
+
+      #[inline]
+      fn into_owned(self) -> Self {
+        self
+      }
+    }
+  };
+  ($($t:ty),*) => {
+    $(impl_into_owned!($t);)*
+  };
+}
+
+#[cfg(feature = "into_owned")]
+impl_into_owned!(bool, f32, f64, u8, u16, u32, u64, u128, i8, i16, i32, i64, i128, usize, isize);
+
 /// Trait for things that can be parsed from CSS syntax.
 pub trait Parse<'i>: Sized {
   /// Parse a value of this type using an existing parser.

src/values/string.rs

@@ -129,9 +129,14 @@ impl<'a> CowArcStr<'a> {
       }
     }
   }
+}
+
+#[cfg(feature = "into_owned")]
+impl<'any> crate::traits::IntoOwned<'any> for CowArcStr<'_> {
+  type Owned = CowArcStr<'any>;
 
   /// Consumes the value and returns an owned clone.
-  pub fn into_owned<'x>(self) -> CowArcStr<'x> {
+  fn into_owned(self) -> Self::Owned {
     if self.borrowed_len_or_max != usize::MAX {
       CowArcStr::from(self.as_ref().to_owned())
     } else {