style: Use cbindgen for clip / -moz-image-region.

This also fixes some of the issues with -moz-image-region, where we just minted
an auto out of the blue.

Differential Revision: https://phabricator.services.mozilla.com/D43474

components/style/values/computed/mod.rs

@@ -683,11 +683,11 @@ impl From<CSSInteger> for PositiveInteger {
 /// A computed positive `<integer>` value or `none`.
 pub type PositiveIntegerOrNone = Either<PositiveInteger, None_>;
 
-/// rect(...)
-pub type ClipRect = generics::ClipRect<LengthOrAuto>;
+/// rect(...) | auto
+pub type ClipRect = generics::GenericClipRect<LengthOrAuto>;
 
 /// rect(...) | auto
-pub type ClipRectOrAuto = Either<ClipRect, Auto>;
+pub type ClipRectOrAuto = generics::GenericClipRectOrAuto<ClipRect>;
 
 /// The computed value of a grid `<track-breadth>`
 pub type TrackBreadth = GenericTrackBreadth<LengthPercentage>;
@@ -707,18 +707,3 @@ pub type GridLine = GenericGridLine<Integer>;
 
 /// `<grid-template-rows> | <grid-template-columns>`
 pub type GridTemplateComponent = GenericGridTemplateComponent<LengthPercentage, Integer>;
-
-impl ClipRectOrAuto {
-    /// Return an auto (default for clip-rect and image-region) value
-    pub fn auto() -> Self {
-        Either::Second(Auto)
-    }
-
-    /// Check if it is auto
-    pub fn is_auto(&self) -> bool {
-        match *self {
-            Either::Second(_) => true,
-            _ => false,
-        }
-    }
-}

components/style/values/generics/mod.rs

@@ -272,9 +272,47 @@ pub struct ZeroToOne<T>(pub T);
     ToShmem,
 )]
 #[css(function = "rect", comma)]
-pub struct ClipRect<LengthOrAuto> {
+#[repr(C)]
+pub struct GenericClipRect<LengthOrAuto> {
     pub top: LengthOrAuto,
     pub right: LengthOrAuto,
     pub bottom: LengthOrAuto,
     pub left: LengthOrAuto,
 }
+
+pub use self::GenericClipRect as ClipRect;
+
+/// Either a clip-rect or `auto`.
+#[allow(missing_docs)]
+#[derive(
+    Animate,
+    Clone,
+    ComputeSquaredDistance,
+    Copy,
+    Debug,
+    MallocSizeOf,
+    Parse,
+    PartialEq,
+    SpecifiedValueInfo,
+    ToAnimatedValue,
+    ToAnimatedZero,
+    ToComputedValue,
+    ToCss,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(C, u8)]
+pub enum GenericClipRectOrAuto<R> {
+    Auto,
+    Rect(R),
+}
+
+pub use self::GenericClipRectOrAuto as ClipRectOrAuto;
+
+impl<L> ClipRectOrAuto<L> {
+    /// Returns the `auto` value.
+    #[inline]
+    pub fn auto() -> Self {
+        ClipRectOrAuto::Auto
+    }
+}

components/style/values/specified/mod.rs

@@ -13,7 +13,7 @@ use super::generics::grid::{GridLine as GenericGridLine, TrackBreadth as Generic
 use super::generics::grid::{TrackList as GenericTrackList, TrackSize as GenericTrackSize};
 use super::generics::transform::IsParallelTo;
 use super::generics::{self, GreaterThanOrEqualToOne, NonNegative};
-use super::{Auto, CSSFloat, CSSInteger, Either, None_};
+use super::{CSSFloat, CSSInteger, Either, None_};
 use crate::context::QuirksMode;
 use crate::parser::{Parse, ParserContext};
 use crate::values::serialize_atom_identifier;
@@ -639,7 +639,7 @@ pub type GridLine = GenericGridLine<Integer>;
 pub type GridTemplateComponent = GenericGridTemplateComponent<LengthPercentage, Integer>;
 
 /// rect(...)
-pub type ClipRect = generics::ClipRect<LengthOrAuto>;
+pub type ClipRect = generics::GenericClipRect<LengthOrAuto>;
 
 impl Parse for ClipRect {
     fn parse<'i, 't>(
@@ -652,7 +652,7 @@ impl Parse for ClipRect {
 
 impl ClipRect {
     /// Parses a rect(<top>, <left>, <bottom>, <right>), allowing quirks.
-    pub fn parse_quirky<'i, 't>(
+    fn parse_quirky<'i, 't>(
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
         allow_quirks: AllowQuirks,
@@ -696,7 +696,7 @@ impl ClipRect {
 }
 
 /// rect(...) | auto
-pub type ClipRectOrAuto = Either<ClipRect, Auto>;
+pub type ClipRectOrAuto = generics::GenericClipRectOrAuto<ClipRect>;
 
 impl ClipRectOrAuto {
     /// Parses a ClipRect or Auto, allowing quirks.
@@ -706,10 +706,10 @@ impl ClipRectOrAuto {
         allow_quirks: AllowQuirks,
     ) -> Result<Self, ParseError<'i>> {
         if let Ok(v) = input.try(|i| ClipRect::parse_quirky(context, i, allow_quirks)) {
-            Ok(Either::First(v))
-        } else {
-            Auto::parse(context, input).map(Either::Second)
+            return Ok(generics::GenericClipRectOrAuto::Rect(v))
         }
+        input.expect_ident_matching("auto")?;
+        Ok(generics::GenericClipRectOrAuto::Auto)
     }
 }