Replace IntegerOrAuto with ZIndex

It's its only use.

components/style/values/computed/mod.rs

@@ -68,7 +68,7 @@ pub use self::list::{ListStyleImage, Quotes};
 pub use self::list::ListStyleType;
 pub use self::outline::OutlineStyle;
 pub use self::percentage::Percentage;
-pub use self::position::{Position, GridAutoFlow, GridTemplateAreas};
+pub use self::position::{GridAutoFlow, GridTemplateAreas, Position, ZIndex};
 pub use self::pointing::Cursor;
 #[cfg(feature = "gecko")]
 pub use self::pointing::CursorImage;
@@ -524,20 +524,6 @@ pub type Opacity = CSSFloat;
 /// A `<integer>` value.
 pub type Integer = CSSInteger;
 
-/// <integer> | auto
-pub type IntegerOrAuto = Either<CSSInteger, Auto>;
-
-impl IntegerOrAuto {
-    /// Returns the integer value if it is an integer, otherwise return
-    /// the given value.
-    pub fn integer_or(&self, auto_value: CSSInteger) -> CSSInteger {
-        match *self {
-            Either::First(n) => n,
-            Either::Second(Auto) => auto_value,
-        }
-    }
-}
-
 /// A wrapper of Integer, but only accept a value >= 1.
 pub type PositiveInteger = GreaterThanOrEqualToOne<CSSInteger>;
 

components/style/values/computed/position.rs

@@ -9,8 +9,9 @@
 
 use std::fmt::{self, Write};
 use style_traits::{CssWriter, ToCss};
-use values::computed::{LengthOrPercentage, Percentage};
+use values::computed::{Integer, LengthOrPercentage, Percentage};
 use values::generics::position::Position as GenericPosition;
+use values::generics::position::ZIndex as GenericZIndex;
 pub use values::specified::position::{GridAutoFlow, GridTemplateAreas};
 
 /// The computed value of a CSS `<position>`
@@ -49,3 +50,6 @@ impl ToCss for Position {
         self.vertical.to_css(dest)
     }
 }
+
+/// A computed value for the `z-index` property.
+pub type ZIndex = GenericZIndex<Integer>;

components/style/values/generics/position.rs

@@ -24,3 +24,36 @@ impl<H, V> Position<H, V> {
         }
     }
 }
+
+/// A generic value for the `z-index` property.
+#[derive(Animate, Clone, ComputeSquaredDistance, Copy, Debug)]
+#[derive(MallocSizeOf, PartialEq, ToAnimatedZero, ToComputedValue, ToCss)]
+pub enum ZIndex<Integer> {
+    /// An integer value.
+    Integer(Integer),
+    /// The keyword `auto`.
+    Auto,
+}
+
+impl<Integer> ZIndex<Integer> {
+    /// Returns `auto`
+    #[inline]
+    pub fn auto() -> Self {
+        ZIndex::Auto
+    }
+
+    /// Returns whether `self` is `auto`.
+    #[inline]
+    pub fn is_auto(self) -> bool {
+        matches!(self, ZIndex::Auto)
+    }
+
+    /// Returns the integer value if it is an integer, or `auto`.
+    #[inline]
+    pub fn integer_or(self, auto: Integer) -> Integer {
+        match self {
+            ZIndex::Integer(n) => n,
+            ZIndex::Auto => auto,
+        }
+    }
+}

components/style/values/specified/mod.rs

@@ -61,7 +61,8 @@ pub use self::list::ListStyleType;
 pub use self::outline::OutlineStyle;
 pub use self::rect::LengthOrNumberRect;
 pub use self::percentage::Percentage;
-pub use self::position::{Position, PositionComponent, GridAutoFlow, GridTemplateAreas};
+pub use self::position::{GridAutoFlow, GridTemplateAreas, Position};
+pub use self::position::{PositionComponent, ZIndex};
 pub use self::pointing::Cursor;
 #[cfg(feature = "gecko")]
 pub use self::pointing::CursorImage;
@@ -518,24 +519,6 @@ impl ToCss for Integer {
     }
 }
 
-/// <integer> | auto
-pub type IntegerOrAuto = Either<Integer, Auto>;
-
-impl IntegerOrAuto {
-    /// Parse `auto` or a positive integer.
-    pub fn parse_positive<'i, 't>(
-        context: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<IntegerOrAuto, ParseError<'i>> {
-        match IntegerOrAuto::parse(context, input) {
-            Ok(Either::First(integer)) if integer.value() <= 0 => {
-                Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
-            }
-            result => result,
-        }
-    }
-}
-
 /// A wrapper of Integer, with value >= 1.
 pub type PositiveInteger = GreaterThanOrEqualToOne<Integer>;
 

components/style/values/specified/position.rs

@@ -20,7 +20,8 @@ use values::{Either, None_};
 use values::computed::{CalcLengthOrPercentage, LengthOrPercentage as ComputedLengthOrPercentage};
 use values::computed::{Context, Percentage, ToComputedValue};
 use values::generics::position::Position as GenericPosition;
-use values::specified::{AllowQuirks, LengthOrPercentage};
+use values::generics::position::ZIndex as GenericZIndex;
+use values::specified::{AllowQuirks, Integer, LengthOrPercentage};
 use values::specified::transform::OriginComponent;
 
 /// The specified value of a CSS `<position>`
@@ -702,3 +703,18 @@ impl GridTemplateAreas {
         Either::Second(None_)
     }
 }
+
+/// A specified value for the `z-index` property.
+pub type ZIndex = GenericZIndex<Integer>;
+
+impl Parse for ZIndex {
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        if input.try(|i| i.expect_ident_matching("auto")).is_ok() {
+            return Ok(GenericZIndex::Auto);
+        }
+        Ok(GenericZIndex::Integer(Integer::parse(context, input)?))
+    }
+}