style: Remove nsCSSValue usage from font code.

Really sorry for the size of the patch.

Differential Revision: https://phabricator.services.mozilla.com/D7753

components/style/cbindgen.toml

@@ -6,7 +6,17 @@ autogen_warning = """/* DO NOT MODIFY THIS MANUALLY! This file was generated usi
  *   1. Get the latest cbindgen using `cargo install --force cbindgen`
  *      a. Alternatively, you can clone `https://github.com/eqrion/cbindgen` and use a tagged release
  *   2. Run `rustup run nightly cbindgen toolkit/library/rust/ --lockfile Cargo.lock --crate style -o layout/style/ServoStyleConsts.h`
- */"""
+ */
+class nsAtom;
+namespace mozilla {
+  namespace css {
+    struct URLValue;
+  }
+  // Work-around weird cbindgen renaming.
+  typedef css::URLValue StyleURLValue;
+  typedef nsAtom StylensAtom;
+}
+"""
 include_guard = "mozilla_ServoStyleConsts_h"
 include_version = true
 braces = "SameLine"
@@ -15,6 +25,10 @@ tab_width = 2
 language = "C++"
 namespaces = ["mozilla"]
 
+[parse]
+parse_deps = true
+include = ["cssparser"]
+
 [struct]
 derive_eq = true
 
@@ -25,9 +39,16 @@ derive_helper_methods = true
 prefix = "Style"
 include = [
   "StyleAppearance",
+  "StyleComputedFontStretchRange",
+  "StyleComputedFontStyleDescriptor",
+  "StyleComputedFontWeightRange",
   "StyleDisplay",
   "StyleDisplayMode",
   "StyleFillRule",
-  "StylePathCommand"
+  "StyleFontDisplay",
+  "StyleFontFaceSourceListComponent",
+  "StyleFontLanguageOverride",
+  "StylePathCommand",
+  "StyleUnicodeRange",
 ]
 item_types = ["enums", "structs", "typedefs"]

components/style/font_face.rs

@@ -24,7 +24,7 @@ use style_traits::values::SequenceWriter;
 use values::computed::font::FamilyName;
 use values::generics::font::FontStyle as GenericFontStyle;
 use values::specified::Angle;
-use values::specified::font::{AbsoluteFontWeight, FontStretch as SpecifiedFontStretch};
+use values::specified::font::{AbsoluteFontWeight, FontStretch};
 #[cfg(feature = "gecko")]
 use values::specified::font::{SpecifiedFontFeatureSettings, SpecifiedFontVariationSettings};
 use values::specified::font::SpecifiedFontStyle;
@@ -45,6 +45,19 @@ impl OneOrMoreSeparated for Source {
     type S = Comma;
 }
 
+/// A POD representation for Gecko. All pointers here are non-owned and as such
+/// can't outlive the rule they came from, but we can't enforce that via C++.
+///
+/// All the strings are of course utf8.
+#[cfg(feature = "gecko")]
+#[repr(u8)]
+#[allow(missing_docs)]
+pub enum FontFaceSourceListComponent {
+    Url(*const ::gecko_bindings::structs::mozilla::css::URLValue),
+    Local(*mut ::gecko_bindings::structs::nsAtom),
+    FormatHint { length: usize, utf8_bytes: *const u8 },
+}
+
 /// A `UrlSource` represents a font-face source that has been specified with a
 /// `url()` function.
 ///
@@ -84,6 +97,7 @@ impl ToCss for UrlSource {
 #[allow(missing_docs)]
 #[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
 #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
+#[repr(u8)]
 pub enum FontDisplay {
     Auto,
     Block,
@@ -92,41 +106,83 @@ pub enum FontDisplay {
     Optional,
 }
 
+macro_rules! impl_range {
+    ($range:ident, $component:ident) => {
+        impl Parse for $range {
+            fn parse<'i, 't>(
+                context: &ParserContext,
+                input: &mut Parser<'i, 't>,
+            ) -> Result<Self, ParseError<'i>> {
+                let first = $component::parse(context, input)?;
+                let second = input
+                    .try(|input| $component::parse(context, input))
+                    .unwrap_or_else(|_| first.clone());
+                Ok($range(first, second))
+            }
+        }
+        impl ToCss for $range {
+            fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+            where
+                W: fmt::Write,
+            {
+                self.0.to_css(dest)?;
+                if self.0 != self.1 {
+                    dest.write_str(" ")?;
+                    self.1.to_css(dest)?;
+                }
+                Ok(())
+            }
+        }
+    }
+}
+
 /// The font-weight descriptor:
 ///
 /// https://drafts.csswg.org/css-fonts-4/#descdef-font-face-font-weight
-#[derive(Clone, Debug, PartialEq, ToCss)]
-pub struct FontWeight(pub AbsoluteFontWeight, pub Option<AbsoluteFontWeight>);
+#[derive(Clone, Debug, PartialEq)]
+pub struct FontWeightRange(pub AbsoluteFontWeight, pub AbsoluteFontWeight);
+impl_range!(FontWeightRange, AbsoluteFontWeight);
 
-impl Parse for FontWeight {
-    fn parse<'i, 't>(
-        context: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<Self, ParseError<'i>> {
-        let first = AbsoluteFontWeight::parse(context, input)?;
-        let second = input
-            .try(|input| AbsoluteFontWeight::parse(context, input))
-            .ok();
-        Ok(FontWeight(first, second))
+/// The computed representation of the above so Gecko can read them easily.
+///
+/// This one is needed because cbindgen doesn't know how to generate
+/// specified::Number.
+#[repr(C)]
+#[allow(missing_docs)]
+pub struct ComputedFontWeightRange(f32, f32);
+
+impl FontWeightRange {
+    /// Returns a computed font-stretch range.
+    pub fn compute(&self) -> ComputedFontWeightRange {
+        ComputedFontWeightRange(self.0.compute().0, self.1.compute().0)
     }
 }
 
 /// The font-stretch descriptor:
 ///
 /// https://drafts.csswg.org/css-fonts-4/#descdef-font-face-font-stretch
-#[derive(Clone, Debug, PartialEq, ToCss)]
-pub struct FontStretch(pub SpecifiedFontStretch, pub Option<SpecifiedFontStretch>);
+#[derive(Clone, Debug, PartialEq,)]
+pub struct FontStretchRange(pub FontStretch, pub FontStretch);
+impl_range!(FontStretchRange, FontStretch);
 
-impl Parse for FontStretch {
-    fn parse<'i, 't>(
-        context: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<Self, ParseError<'i>> {
-        let first = SpecifiedFontStretch::parse(context, input)?;
-        let second = input
-            .try(|input| SpecifiedFontStretch::parse(context, input))
-            .ok();
-        Ok(FontStretch(first, second))
+/// The computed representation of the above, so that
+/// Gecko can read them easily.
+#[repr(C)]
+#[allow(missing_docs)]
+pub struct ComputedFontStretchRange(f32, f32);
+
+impl FontStretchRange {
+    /// Returns a computed font-stretch range.
+    pub fn compute(&self) -> ComputedFontStretchRange {
+        fn compute_stretch(s: &FontStretch) -> f32 {
+            match *s {
+                FontStretch::Keyword(ref kw) => kw.compute().0,
+                FontStretch::Stretch(ref p) => p.get(),
+                FontStretch::System(..) => unreachable!(),
+            }
+        }
+
+        ComputedFontStretchRange(compute_stretch(&self.0), compute_stretch(&self.1))
     }
 }
 
@@ -141,6 +197,16 @@ pub enum FontStyle {
     Oblique(Angle, Angle),
 }
 
+/// The computed representation of the above, with angles in degrees, so that
+/// Gecko can read them easily.
+#[repr(u8)]
+#[allow(missing_docs)]
+pub enum ComputedFontStyleDescriptor {
+    Normal,
+    Italic,
+    Oblique(f32, f32),
+}
+
 impl Parse for FontStyle {
     fn parse<'i, 't>(
         context: &ParserContext,
@@ -185,6 +251,22 @@ impl ToCss for FontStyle {
     }
 }
 
+impl FontStyle {
+    /// Returns a computed font-style descriptor.
+    pub fn compute(&self) -> ComputedFontStyleDescriptor {
+        match *self {
+            FontStyle::Normal => ComputedFontStyleDescriptor::Normal,
+            FontStyle::Italic => ComputedFontStyleDescriptor::Italic,
+            FontStyle::Oblique(ref first, ref second) => {
+                ComputedFontStyleDescriptor::Oblique(
+                    SpecifiedFontStyle::compute_angle_degrees(first),
+                    SpecifiedFontStyle::compute_angle_degrees(second),
+                )
+            }
+        }
+    }
+}
+
 /// Parse the block inside a `@font-face` rule.
 ///
 /// Note that the prelude parsing code lives in the `stylesheets` module.
@@ -459,10 +541,10 @@ font_face_descriptors! {
         "font-style" style / mStyle: FontStyle,
 
         /// The weight of this font face.
-        "font-weight" weight / mWeight: FontWeight,
+        "font-weight" weight / mWeight: FontWeightRange,
 
         /// The stretch of this font face.
-        "font-stretch" stretch / mStretch: FontStretch,
+        "font-stretch" stretch / mStretch: FontStretchRange,
 
         /// The display of this font face.
         "font-display" display / mDisplay: FontDisplay,

components/style/gecko/rules.rs

@@ -4,139 +4,10 @@
 
 //! Bindings for CSS Rule objects
 
-use byteorder::{BigEndian, WriteBytesExt};
 use counter_style::{self, CounterBound};
-use cssparser::UnicodeRange;
-use font_face::{FontDisplay, FontWeight, FontStretch, FontStyle, Source};
+use font_face::Source;
 use gecko_bindings::structs::{self, nsCSSValue};
 use gecko_bindings::sugar::ns_css_value::ToNsCssValue;
-use properties::longhands::font_language_override;
-use std::str;
-use values::computed::font::FamilyName;
-use values::generics::font::FontTag;
-use values::specified::font::{AbsoluteFontWeight, FontStretch as SpecifiedFontStretch};
-use values::specified::font::{SpecifiedFontFeatureSettings, SpecifiedFontVariationSettings};
-use values::specified::font::SpecifiedFontStyle;
-
-impl<'a> ToNsCssValue for &'a FamilyName {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        nscssvalue.set_string_from_atom(&self.name)
-    }
-}
-
-impl<'a> ToNsCssValue for &'a SpecifiedFontStretch {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        let number = match *self {
-            SpecifiedFontStretch::Stretch(ref p) => p.get(),
-            SpecifiedFontStretch::Keyword(ref kw) => kw.compute().0,
-            SpecifiedFontStretch::System(..) => unreachable!(),
-        };
-        nscssvalue.set_font_stretch(number);
-    }
-}
-
-impl<'a> ToNsCssValue for &'a AbsoluteFontWeight {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        nscssvalue.set_font_weight(self.compute().0)
-    }
-}
-
-impl ToNsCssValue for FontTag {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        let mut raw = [0u8; 4];
-        (&mut raw[..]).write_u32::<BigEndian>(self.0).unwrap();
-        nscssvalue.set_string(str::from_utf8(&raw).unwrap());
-    }
-}
-
-impl<'a> ToNsCssValue for &'a SpecifiedFontFeatureSettings {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        if self.0.is_empty() {
-            nscssvalue.set_normal();
-            return;
-        }
-
-        nscssvalue.set_pair_list(self.0.iter().map(|entry| {
-            let mut index = nsCSSValue::null();
-            index.set_integer(entry.value.value());
-            (entry.tag.into(), index)
-        }))
-    }
-}
-
-impl<'a> ToNsCssValue for &'a SpecifiedFontVariationSettings {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        if self.0.is_empty() {
-            nscssvalue.set_normal();
-            return;
-        }
-
-        nscssvalue.set_pair_list(self.0.iter().map(|entry| {
-            let mut value = nsCSSValue::null();
-            value.set_number(entry.value.into());
-            (entry.tag.into(), value)
-        }))
-    }
-}
-
-macro_rules! descriptor_range_conversion {
-    ($name:ident) => {
-        impl<'a> ToNsCssValue for &'a $name {
-            fn convert(self, nscssvalue: &mut nsCSSValue) {
-                let $name(ref first, ref second) = *self;
-                let second = match *second {
-                    None => {
-                        nscssvalue.set_from(first);
-                        return;
-                    },
-                    Some(ref second) => second,
-                };
-
-                let mut a = nsCSSValue::null();
-                let mut b = nsCSSValue::null();
-
-                a.set_from(first);
-                b.set_from(second);
-
-                nscssvalue.set_pair(&a, &b);
-            }
-        }
-    };
-}
-
-descriptor_range_conversion!(FontWeight);
-descriptor_range_conversion!(FontStretch);
-
-impl<'a> ToNsCssValue for &'a FontStyle {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        match *self {
-            FontStyle::Normal => nscssvalue.set_normal(),
-            FontStyle::Italic => nscssvalue.set_enum(structs::NS_FONT_STYLE_ITALIC as i32),
-            FontStyle::Oblique(ref first, ref second) => {
-                let mut a = nsCSSValue::null();
-                let mut b = nsCSSValue::null();
-
-                a.set_font_style(SpecifiedFontStyle::compute_angle(first).degrees());
-                b.set_font_style(SpecifiedFontStyle::compute_angle(second).degrees());
-
-                nscssvalue.set_pair(&a, &b);
-            },
-        }
-    }
-}
-
-impl<'a> ToNsCssValue for &'a font_language_override::SpecifiedValue {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        match *self {
-            font_language_override::SpecifiedValue::Normal => nscssvalue.set_normal(),
-            font_language_override::SpecifiedValue::Override(ref lang) => {
-                nscssvalue.set_string(&*lang)
-            },
-            // This path is unreachable because the descriptor is only specified by the user.
-            font_language_override::SpecifiedValue::System(_) => unreachable!(),
-        }
-    }
-}
 
 impl<'a> ToNsCssValue for &'a Vec<Source> {
     fn convert(self, nscssvalue: &mut nsCSSValue) {
@@ -175,31 +46,6 @@ impl<'a> ToNsCssValue for &'a Vec<Source> {
     }
 }
 
-impl<'a> ToNsCssValue for &'a Vec<UnicodeRange> {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        let target_ranges = nscssvalue
-            .set_array((self.len() * 2) as i32)
-            .as_mut_slice()
-            .chunks_mut(2);
-        for (range, target) in self.iter().zip(target_ranges) {
-            target[0].set_integer(range.start as i32);
-            target[1].set_integer(range.end as i32);
-        }
-    }
-}
-
-impl<'a> ToNsCssValue for &'a FontDisplay {
-    fn convert(self, nscssvalue: &mut nsCSSValue) {
-        nscssvalue.set_enum(match *self {
-            FontDisplay::Auto => structs::NS_FONT_DISPLAY_AUTO,
-            FontDisplay::Block => structs::NS_FONT_DISPLAY_BLOCK,
-            FontDisplay::Swap => structs::NS_FONT_DISPLAY_SWAP,
-            FontDisplay::Fallback => structs::NS_FONT_DISPLAY_FALLBACK,
-            FontDisplay::Optional => structs::NS_FONT_DISPLAY_OPTIONAL,
-        } as i32)
-    }
-}
-
 impl<'a> ToNsCssValue for &'a counter_style::System {
     fn convert(self, nscssvalue: &mut nsCSSValue) {
         use counter_style::System::*;

components/style/gecko_bindings/sugar/ns_css_value.rs

@@ -177,21 +177,6 @@ impl nsCSSValue {
         self.set_string_from_atom_internal(s, nsCSSUnit::eCSSUnit_Local_Font);
     }
 
-    /// Set to a font stretch.
-    pub fn set_font_stretch(&mut self, s: f32) {
-        unsafe { bindings::Gecko_CSSValue_SetFontStretch(self, s) }
-    }
-
-    /// Set to a font style
-    pub fn set_font_style(&mut self, s: f32) {
-        unsafe { bindings::Gecko_CSSValue_SetFontSlantStyle(self, s) }
-    }
-
-    /// Set to a font weight
-    pub fn set_font_weight(&mut self, w: f32) {
-        unsafe { bindings::Gecko_CSSValue_SetFontWeight(self, w) }
-    }
-
     fn set_int_internal(&mut self, value: i32, unit: nsCSSUnit) {
         unsafe { bindings::Gecko_CSSValue_SetInt(self, value, unit) }
     }

components/style/values/computed/font.rs

@@ -747,6 +747,7 @@ pub type FontVariationSettings = FontSettings<VariationValue<Number>>;
 /// it and store it as a 32-bit integer
 /// (see http://www.microsoft.com/typography/otspec/languagetags.htm).
 #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq)]
+#[repr(C)]
 pub struct FontLanguageOverride(pub u32);
 
 impl FontLanguageOverride {

components/style/values/computed/percentage.rs

@@ -27,6 +27,7 @@ use values::generics::NonNegative;
     ToAnimatedZero,
     ToComputedValue,
 )]
+#[repr(C)]
 pub struct Percentage(pub CSSFloat);
 
 impl Percentage {

components/style/values/specified/font.rs

@@ -292,14 +292,16 @@ pub const FONT_STYLE_OBLIQUE_MAX_ANGLE_DEGREES: f32 = 90.;
 pub const FONT_STYLE_OBLIQUE_MIN_ANGLE_DEGREES: f32 = -90.;
 
 impl SpecifiedFontStyle {
-    /// Gets a clamped angle from a specified Angle.
-    pub fn compute_angle(angle: &Angle) -> ComputedAngle {
-        ComputedAngle::Deg(
-            angle
-                .degrees()
-                .max(FONT_STYLE_OBLIQUE_MIN_ANGLE_DEGREES)
-                .min(FONT_STYLE_OBLIQUE_MAX_ANGLE_DEGREES),
-        )
+    /// Gets a clamped angle in degrees from a specified Angle.
+    pub fn compute_angle_degrees(angle: &Angle) -> f32 {
+        angle
+            .degrees()
+            .max(FONT_STYLE_OBLIQUE_MIN_ANGLE_DEGREES)
+            .min(FONT_STYLE_OBLIQUE_MAX_ANGLE_DEGREES)
+    }
+
+    fn compute_angle(angle: &Angle) -> ComputedAngle {
+        ComputedAngle::Deg(Self::compute_angle_degrees(angle))
     }
 
     /// Parse a suitable angle for font-style: oblique.
@@ -380,6 +382,7 @@ impl Parse for FontStyle {
 /// https://drafts.csswg.org/css-fonts-4/#font-stretch-prop
 #[allow(missing_docs)]
 #[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss)]
+#[repr(u8)]
 pub enum FontStretch {
     Stretch(Percentage),
     Keyword(FontStretchKeyword),
@@ -2057,6 +2060,29 @@ impl FontLanguageOverride {
         FontLanguageOverride::Normal
     }
 
+    /// The ToComputedValue implementation for non-system-font
+    /// FontLanguageOverride, used for @font-face descriptors.
+    #[inline]
+    pub fn compute_non_system(&self) -> computed::FontLanguageOverride {
+        match *self {
+            FontLanguageOverride::Normal => computed::FontLanguageOverride(0),
+            FontLanguageOverride::Override(ref lang) => {
+                if lang.is_empty() || lang.len() > 4 {
+                    return computed::FontLanguageOverride(0);
+                }
+                let mut bytes = [b' '; 4];
+                for (byte, lang_byte) in bytes.iter_mut().zip(lang.as_bytes()) {
+                    if !lang_byte.is_ascii() {
+                        return computed::FontLanguageOverride(0);
+                    }
+                    *byte = *lang_byte;
+                }
+                computed::FontLanguageOverride(BigEndian::read_u32(&bytes))
+            },
+            FontLanguageOverride::System(..) => unreachable!(),
+        }
+    }
+
     system_font_methods!(FontLanguageOverride, font_language_override);
 }
 
@@ -2066,19 +2092,8 @@ impl ToComputedValue for FontLanguageOverride {
     #[inline]
     fn to_computed_value(&self, context: &Context) -> computed::FontLanguageOverride {
         match *self {
-            FontLanguageOverride::Normal => computed::FontLanguageOverride(0),
-            FontLanguageOverride::Override(ref lang) => {
-                if lang.is_empty() || lang.len() > 4 || !lang.is_ascii() {
-                    return computed::FontLanguageOverride(0);
-                }
-                let mut computed_lang = lang.to_string();
-                while computed_lang.len() < 4 {
-                    computed_lang.push(' ');
-                }
-                let bytes = computed_lang.into_bytes();
-                computed::FontLanguageOverride(BigEndian::read_u32(&bytes))
-            },
             FontLanguageOverride::System(_) => self.compute_system(context),
+            _ => self.compute_non_system(),
         }
     }
     #[inline]