1 files changed, 531 insertions, 0 deletions
diff --git a/servo/components/style/values/computed/length.rs b/servo/components/style/values/computed/length.rs
new file mode 100644
index 0000000000..e75676a76d
--- /dev/null
+++ b/servo/components/style/values/computed/length.rs
@@ -0,0 +1,531 @@
+/* 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/. */
+
+//! `<length>` computed values, and related ones.
+
+use super::{Context, Number, ToComputedValue};
+use crate::values::animated::ToAnimatedValue;
+use crate::values::computed::NonNegativeNumber;
+use crate::values::generics::length as generics;
+use crate::values::generics::length::{
+    GenericLengthOrNumber, GenericLengthPercentageOrNormal, GenericMaxSize, GenericSize,
+};
+use crate::values::generics::NonNegative;
+use crate::values::specified::length::{AbsoluteLength, FontBaseSize, LineHeightBase};
+use crate::values::{specified, CSSFloat};
+use crate::Zero;
+use app_units::Au;
+use std::fmt::{self, Write};
+use std::ops::{Add, AddAssign, Div, Mul, MulAssign, Neg, Sub};
+use style_traits::{CSSPixel, CssWriter, ToCss};
+
+pub use super::image::Image;
+pub use super::length_percentage::{LengthPercentage, NonNegativeLengthPercentage};
+pub use crate::values::specified::url::UrlOrNone;
+pub use crate::values::specified::{Angle, BorderStyle, Time};
+
+impl ToComputedValue for specified::NoCalcLength {
+    type ComputedValue = Length;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
+        self.to_computed_value_with_base_size(
+            context,
+            FontBaseSize::CurrentStyle,
+            LineHeightBase::CurrentStyle,
+        )
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &Self::ComputedValue) -> Self {
+        Self::Absolute(AbsoluteLength::Px(computed.px()))
+    }
+}
+
+impl specified::NoCalcLength {
+    /// Computes a length with a given font-relative base size.
+    pub fn to_computed_value_with_base_size(
+        &self,
+        context: &Context,
+        base_size: FontBaseSize,
+        line_height_base: LineHeightBase,
+    ) -> Length {
+        match *self {
+            Self::Absolute(length) => length.to_computed_value(context),
+            Self::FontRelative(length) => {
+                length.to_computed_value(context, base_size, line_height_base)
+            },
+            Self::ViewportPercentage(length) => length.to_computed_value(context),
+            Self::ContainerRelative(length) => length.to_computed_value(context),
+            Self::ServoCharacterWidth(length) => length
+                .to_computed_value(context.style().get_font().clone_font_size().computed_size()),
+        }
+    }
+}
+
+impl ToComputedValue for specified::Length {
+    type ComputedValue = Length;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
+        match *self {
+            Self::NoCalc(l) => l.to_computed_value(context),
+            Self::Calc(ref calc) => {
+                let result = calc.to_computed_value(context);
+                debug_assert!(
+                    result.to_length().is_some(),
+                    "{:?} didn't resolve to a length: {:?}",
+                    calc,
+                    result,
+                );
+                result.to_length().unwrap_or_else(Length::zero)
+            },
+        }
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &Self::ComputedValue) -> Self {
+        Self::NoCalc(specified::NoCalcLength::from_computed_value(computed))
+    }
+}
+
+/// Some boilerplate to share between negative and non-negative
+/// length-percentage or auto.
+macro_rules! computed_length_percentage_or_auto {
+    ($inner:ty) => {
+        /// Returns the used value.
+        #[inline]
+        pub fn to_used_value(&self, percentage_basis: Au) -> Option<Au> {
+            match *self {
+                Self::Auto => None,
+                Self::LengthPercentage(ref lp) => Some(lp.to_used_value(percentage_basis)),
+            }
+        }
+
+        /// Returns true if the computed value is absolute 0 or 0%.
+        #[inline]
+        pub fn is_definitely_zero(&self) -> bool {
+            use crate::values::generics::length::LengthPercentageOrAuto::*;
+            match *self {
+                LengthPercentage(ref l) => l.is_definitely_zero(),
+                Auto => false,
+            }
+        }
+    };
+}
+
+/// A computed type for `<length-percentage> | auto`.
+pub type LengthPercentageOrAuto = generics::GenericLengthPercentageOrAuto<LengthPercentage>;
+
+impl LengthPercentageOrAuto {
+    /// Clamps the value to a non-negative value.
+    pub fn clamp_to_non_negative(self) -> Self {
+        use crate::values::generics::length::LengthPercentageOrAuto::*;
+        match self {
+            LengthPercentage(l) => LengthPercentage(l.clamp_to_non_negative()),
+            Auto => Auto,
+        }
+    }
+
+    /// Convert to have a borrow inside the enum
+    pub fn as_ref(&self) -> generics::GenericLengthPercentageOrAuto<&LengthPercentage> {
+        use crate::values::generics::length::LengthPercentageOrAuto::*;
+        match *self {
+            LengthPercentage(ref lp) => LengthPercentage(lp),
+            Auto => Auto,
+        }
+    }
+
+    computed_length_percentage_or_auto!(LengthPercentage);
+}
+
+impl generics::GenericLengthPercentageOrAuto<&LengthPercentage> {
+    /// Resolves the percentage.
+    #[inline]
+    pub fn percentage_relative_to(&self, basis: Length) -> LengthOrAuto {
+        use crate::values::generics::length::LengthPercentageOrAuto::*;
+        match self {
+            LengthPercentage(length_percentage) => {
+                LengthPercentage(length_percentage.percentage_relative_to(basis))
+            },
+            Auto => Auto,
+        }
+    }
+
+    /// Maybe resolves the percentage.
+    #[inline]
+    pub fn maybe_percentage_relative_to(&self, basis: Option<Length>) -> LengthOrAuto {
+        use crate::values::generics::length::LengthPercentageOrAuto::*;
+        match self {
+            LengthPercentage(length_percentage) => length_percentage
+                .maybe_percentage_relative_to(basis)
+                .map_or(Auto, LengthPercentage),
+            Auto => Auto,
+        }
+    }
+}
+
+/// A wrapper of LengthPercentageOrAuto, whose value must be >= 0.
+pub type NonNegativeLengthPercentageOrAuto =
+    generics::GenericLengthPercentageOrAuto<NonNegativeLengthPercentage>;
+
+impl NonNegativeLengthPercentageOrAuto {
+    computed_length_percentage_or_auto!(NonNegativeLengthPercentage);
+}
+
+#[cfg(feature = "servo")]
+impl MaxSize {
+    /// Convert the computed value into used value.
+    #[inline]
+    pub fn to_used_value(&self, percentage_basis: Au) -> Option<Au> {
+        match *self {
+            GenericMaxSize::None => None,
+            GenericMaxSize::LengthPercentage(ref lp) => Some(lp.to_used_value(percentage_basis)),
+        }
+    }
+}
+
+impl Size {
+    /// Convert the computed value into used value.
+    #[inline]
+    #[cfg(feature = "servo")]
+    pub fn to_used_value(&self, percentage_basis: Au) -> Option<Au> {
+        match *self {
+            GenericSize::Auto => None,
+            GenericSize::LengthPercentage(ref lp) => Some(lp.to_used_value(percentage_basis)),
+        }
+    }
+
+    /// Returns true if the computed value is absolute 0 or 0%.
+    #[inline]
+    pub fn is_definitely_zero(&self) -> bool {
+        match *self {
+            Self::Auto => false,
+            Self::LengthPercentage(ref lp) => lp.is_definitely_zero(),
+            #[cfg(feature = "gecko")]
+            Self::MinContent |
+            Self::MaxContent |
+            Self::FitContent |
+            Self::MozAvailable |
+            Self::FitContentFunction(_) => false,
+        }
+    }
+}
+
+/// The computed `<length>` value.
+#[derive(
+    Animate,
+    Clone,
+    ComputeSquaredDistance,
+    Copy,
+    Deserialize,
+    MallocSizeOf,
+    PartialEq,
+    PartialOrd,
+    Serialize,
+    ToAnimatedValue,
+    ToAnimatedZero,
+    ToComputedValue,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(C)]
+pub struct CSSPixelLength(CSSFloat);
+
+impl fmt::Debug for CSSPixelLength {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(f)?;
+        f.write_str(" px")
+    }
+}
+
+impl CSSPixelLength {
+    /// Return a new CSSPixelLength.
+    #[inline]
+    pub fn new(px: CSSFloat) -> Self {
+        CSSPixelLength(px)
+    }
+
+    /// Returns a normalized (NaN turned to zero) version of this length.
+    #[inline]
+    pub fn normalized(self) -> Self {
+        Self::new(crate::values::normalize(self.0))
+    }
+
+    /// Returns a finite (normalized and clamped to float min and max) version of this length.
+    #[inline]
+    pub fn finite(self) -> Self {
+        Self::new(crate::values::normalize(self.0).min(f32::MAX).max(f32::MIN))
+    }
+
+    /// Scale the length by a given amount.
+    #[inline]
+    pub fn scale_by(self, scale: CSSFloat) -> Self {
+        CSSPixelLength(self.0 * scale)
+    }
+
+    /// Return the containing pixel value.
+    #[inline]
+    pub fn px(self) -> CSSFloat {
+        self.0
+    }
+
+    /// Return the length with app_unit i32 type.
+    #[inline]
+    pub fn to_i32_au(self) -> i32 {
+        Au::from(self).0
+    }
+
+    /// Return the absolute value of this length.
+    #[inline]
+    pub fn abs(self) -> Self {
+        CSSPixelLength::new(self.0.abs())
+    }
+
+    /// Return the clamped value of this length.
+    #[inline]
+    pub fn clamp_to_non_negative(self) -> Self {
+        CSSPixelLength::new(self.0.max(0.))
+    }
+
+    /// Returns the minimum between `self` and `other`.
+    #[inline]
+    pub fn min(self, other: Self) -> Self {
+        CSSPixelLength::new(self.0.min(other.0))
+    }
+
+    /// Returns the maximum between `self` and `other`.
+    #[inline]
+    pub fn max(self, other: Self) -> Self {
+        CSSPixelLength::new(self.0.max(other.0))
+    }
+
+    /// Sets `self` to the maximum between `self` and `other`.
+    #[inline]
+    pub fn max_assign(&mut self, other: Self) {
+        *self = self.max(other);
+    }
+
+    /// Clamp the value to a lower bound and an optional upper bound.
+    ///
+    /// Can be used for example with `min-width` and `max-width`.
+    #[inline]
+    pub fn clamp_between_extremums(self, min_size: Self, max_size: Option<Self>) -> Self {
+        self.clamp_below_max(max_size).max(min_size)
+    }
+
+    /// Clamp the value to an optional upper bound.
+    ///
+    /// Can be used for example with `max-width`.
+    #[inline]
+    pub fn clamp_below_max(self, max_size: Option<Self>) -> Self {
+        match max_size {
+            None => self,
+            Some(max_size) => self.min(max_size),
+        }
+    }
+}
+
+impl num_traits::Zero for CSSPixelLength {
+    fn zero() -> Self {
+        CSSPixelLength::new(0.)
+    }
+
+    fn is_zero(&self) -> bool {
+        self.px() == 0.
+    }
+}
+
+impl ToCss for CSSPixelLength {
+    #[inline]
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
+        self.0.to_css(dest)?;
+        dest.write_str("px")
+    }
+}
+
+impl std::iter::Sum for CSSPixelLength {
+    fn sum<I: Iterator<Item = Self>>(iter: I) -> Self {
+        iter.fold(Length::zero(), Add::add)
+    }
+}
+
+impl Add for CSSPixelLength {
+    type Output = Self;
+
+    #[inline]
+    fn add(self, other: Self) -> Self {
+        Self::new(self.px() + other.px())
+    }
+}
+
+impl AddAssign for CSSPixelLength {
+    #[inline]
+    fn add_assign(&mut self, other: Self) {
+        self.0 += other.0;
+    }
+}
+
+impl Div for CSSPixelLength {
+    type Output = CSSFloat;
+
+    #[inline]
+    fn div(self, other: Self) -> CSSFloat {
+        self.px() / other.px()
+    }
+}
+
+impl Div<CSSFloat> for CSSPixelLength {
+    type Output = Self;
+
+    #[inline]
+    fn div(self, other: CSSFloat) -> Self {
+        Self::new(self.px() / other)
+    }
+}
+
+impl MulAssign<CSSFloat> for CSSPixelLength {
+    #[inline]
+    fn mul_assign(&mut self, other: CSSFloat) {
+        self.0 *= other;
+    }
+}
+
+impl Mul<CSSFloat> for CSSPixelLength {
+    type Output = Self;
+
+    #[inline]
+    fn mul(self, other: CSSFloat) -> Self {
+        Self::new(self.px() * other)
+    }
+}
+
+impl Neg for CSSPixelLength {
+    type Output = Self;
+
+    #[inline]
+    fn neg(self) -> Self {
+        CSSPixelLength::new(-self.0)
+    }
+}
+
+impl Sub for CSSPixelLength {
+    type Output = Self;
+
+    #[inline]
+    fn sub(self, other: Self) -> Self {
+        Self::new(self.px() - other.px())
+    }
+}
+
+impl From<CSSPixelLength> for Au {
+    #[inline]
+    fn from(len: CSSPixelLength) -> Self {
+        Au::from_f32_px(len.0)
+    }
+}
+
+impl From<Au> for CSSPixelLength {
+    #[inline]
+    fn from(len: Au) -> Self {
+        CSSPixelLength::new(len.to_f32_px())
+    }
+}
+
+impl From<CSSPixelLength> for euclid::Length<CSSFloat, CSSPixel> {
+    #[inline]
+    fn from(length: CSSPixelLength) -> Self {
+        Self::new(length.0)
+    }
+}
+
+/// An alias of computed `<length>` value.
+pub type Length = CSSPixelLength;
+
+/// Either a computed `<length>` or the `auto` keyword.
+pub type LengthOrAuto = generics::GenericLengthPercentageOrAuto<Length>;
+
+/// Either a non-negative `<length>` or the `auto` keyword.
+pub type NonNegativeLengthOrAuto = generics::GenericLengthPercentageOrAuto<NonNegativeLength>;
+
+/// Either a computed `<length>` or a `<number>` value.
+pub type LengthOrNumber = GenericLengthOrNumber<Length, Number>;
+
+/// A wrapper of Length, whose value must be >= 0.
+pub type NonNegativeLength = NonNegative<Length>;
+
+impl ToAnimatedValue for NonNegativeLength {
+    type AnimatedValue = Length;
+
+    #[inline]
+    fn to_animated_value(self) -> Self::AnimatedValue {
+        self.0
+    }
+
+    #[inline]
+    fn from_animated_value(animated: Self::AnimatedValue) -> Self {
+        NonNegativeLength::new(animated.px().max(0.))
+    }
+}
+
+impl NonNegativeLength {
+    /// Create a NonNegativeLength.
+    #[inline]
+    pub fn new(px: CSSFloat) -> Self {
+        NonNegative(Length::new(px.max(0.)))
+    }
+
+    /// Return the pixel value of |NonNegativeLength|.
+    #[inline]
+    pub fn px(&self) -> CSSFloat {
+        self.0.px()
+    }
+
+    #[inline]
+    /// Ensures it is non negative
+    pub fn clamp(self) -> Self {
+        if (self.0).0 < 0. {
+            Self::zero()
+        } else {
+            self
+        }
+    }
+}
+
+impl From<Length> for NonNegativeLength {
+    #[inline]
+    fn from(len: Length) -> Self {
+        NonNegative(len)
+    }
+}
+
+impl From<Au> for NonNegativeLength {
+    #[inline]
+    fn from(au: Au) -> Self {
+        NonNegative(au.into())
+    }
+}
+
+impl From<NonNegativeLength> for Au {
+    #[inline]
+    fn from(non_negative_len: NonNegativeLength) -> Self {
+        Au::from(non_negative_len.0)
+    }
+}
+
+/// Either a computed NonNegativeLengthPercentage or the `normal` keyword.
+pub type NonNegativeLengthPercentageOrNormal =
+    GenericLengthPercentageOrNormal<NonNegativeLengthPercentage>;
+
+/// Either a non-negative `<length>` or a `<number>`.
+pub type NonNegativeLengthOrNumber = GenericLengthOrNumber<NonNegativeLength, NonNegativeNumber>;
+
+/// A computed value for `min-width`, `min-height`, `width` or `height` property.
+pub type Size = GenericSize<NonNegativeLengthPercentage>;
+
+/// A computed value for `max-width` or `min-height` property.
+pub type MaxSize = GenericMaxSize<NonNegativeLengthPercentage>;