Auto merge of #15331 - Manishearth:stylo-presattr, r=emilio,bz

Basic handling framework for presentation attributes in Stylo, with handling for font-size and color

https://bugzilla.mozilla.org/show_bug.cgi?id=1330041

r=emilio,bz

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6 files changed, 126 insertions, 24 deletions

diff --git a/components/script/dom/htmlfontelement.rs b/components/script/dom/htmlfontelement.rs
index 0eca01a47f9..80a0266595c 100644
--- a/components/script/dom/htmlfontelement.rs
+++ b/components/script/dom/htmlfontelement.rs
@@ -123,7 +123,7 @@ impl HTMLFontElementLayoutHelpers for LayoutJS<HTMLFontElement> {
 }
 
 /// https://html.spec.whatwg.org/multipage/#rules-for-parsing-a-legacy-font-size
-pub fn parse_legacy_font_size(mut input: &str) -> Option<&'static str> {
+fn parse_length(mut input: &str) -> Option<specified::Length> {
     // Steps 1 & 2 are not relevant
 
     // Step 3
@@ -153,8 +153,8 @@ pub fn parse_legacy_font_size(mut input: &str) -> Option<&'static str> {
 
     // Steps 6, 7, 8
     let mut value = match read_numbers(input_chars) {
-        (Some(v), _) => v,
-        (None, _) => return None,
+        (Some(v), _) if v >= 0 => v,
+        _ => return None,
     };
 
     // Step 9
@@ -165,18 +165,5 @@ pub fn parse_legacy_font_size(mut input: &str) -> Option<&'static str> {
     }
 
     // Steps 10, 11, 12
-    Some(match value {
-        n if n >= 7 => "xxx-large",
-        6 => "xx-large",
-        5 => "x-large",
-        4 => "large",
-        3 => "medium",
-        2 => "small",
-        n if n <= 1 => "x-small",
-        _ => unreachable!(),
-    })
-}
-
-fn parse_length(value: &str) -> Option<specified::Length> {
-    parse_legacy_font_size(&value).and_then(|parsed| specified::Length::from_str(&parsed))
+    Some(specified::Length::from_font_size_int(value as u8))
 }
diff --git a/components/style/gecko/wrapper.rs b/components/style/gecko/wrapper.rs
index b73db50a50b..872fc06486c 100644
--- a/components/style/gecko/wrapper.rs
+++ b/components/style/gecko/wrapper.rs
@@ -30,7 +30,8 @@ use gecko_bindings::bindings::{Gecko_IsUnvisitedLink, Gecko_IsVisitedLink, Gecko
 use gecko_bindings::bindings::{Gecko_SetNodeFlags, Gecko_UnsetNodeFlags};
 use gecko_bindings::bindings::Gecko_ClassOrClassList;
 use gecko_bindings::bindings::Gecko_GetAnimationRule;
-use gecko_bindings::bindings::Gecko_GetServoDeclarationBlock;
+use gecko_bindings::bindings::Gecko_GetHTMLPresentationAttrDeclarationBlock;
+use gecko_bindings::bindings::Gecko_GetStyleAttrDeclarationBlock;
 use gecko_bindings::bindings::Gecko_GetStyleContext;
 use gecko_bindings::structs;
 use gecko_bindings::structs::{RawGeckoElement, RawGeckoNode};
@@ -42,6 +43,7 @@ use parking_lot::RwLock;
 use parser::ParserContextExtraData;
 use properties::{ComputedValues, parse_style_attribute};
 use properties::PropertyDeclarationBlock;
+use rule_tree::CascadeLevel as ServoCascadeLevel;
 use selector_parser::{ElementExt, Snapshot};
 use selectors::Element;
 use selectors::parser::{AttrSelector, NamespaceConstraint};
@@ -385,7 +387,7 @@ impl<'le> TElement for GeckoElement<'le> {
     }
 
     fn style_attribute(&self) -> Option<&Arc<RwLock<PropertyDeclarationBlock>>> {
-        let declarations = unsafe { Gecko_GetServoDeclarationBlock(self.0) };
+        let declarations = unsafe { Gecko_GetStyleAttrDeclarationBlock(self.0) };
         declarations.map(|s| s.as_arc_opt()).unwrap_or(None)
     }
 
@@ -483,10 +485,16 @@ impl<'le> PartialEq for GeckoElement<'le> {
 }
 
 impl<'le> PresentationalHintsSynthetizer for GeckoElement<'le> {
-    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, _hints: &mut V)
+    fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, hints: &mut V)
         where V: Push<ApplicableDeclarationBlock>,
     {
-        // FIXME(bholley) - Need to implement this.
+        let declarations = unsafe { Gecko_GetHTMLPresentationAttrDeclarationBlock(self.0) };
+        let declarations = declarations.and_then(|s| s.as_arc_opt());
+        if let Some(decl) = declarations {
+            hints.push(
+                ApplicableDeclarationBlock::from_declarations(Clone::clone(decl), ServoCascadeLevel::PresHints)
+            );
+        }
     }
 }
 
diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index eafce93ea25..b16d0a442b3 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -499,7 +499,11 @@ extern "C" {
      -> u32;
 }
 extern "C" {
-    pub fn Gecko_GetServoDeclarationBlock(element: RawGeckoElementBorrowed)
+    pub fn Gecko_GetStyleAttrDeclarationBlock(element: RawGeckoElementBorrowed)
+     -> RawServoDeclarationBlockStrongBorrowedOrNull;
+}
+extern "C" {
+    pub fn Gecko_GetHTMLPresentationAttrDeclarationBlock(element: RawGeckoElementBorrowed)
      -> RawServoDeclarationBlockStrongBorrowedOrNull;
 }
 extern "C" {
@@ -1392,6 +1396,13 @@ extern "C" {
                                                          nsCSSPropertyID);
 }
 extern "C" {
+    pub fn Servo_DeclarationBlock_AddPresValue(declarations:
+                                                   RawServoDeclarationBlockBorrowed,
+                                               property: nsCSSPropertyID,
+                                               css_value:
+                                                   nsCSSValueBorrowedMut);
+}
+extern "C" {
     pub fn Servo_CSSSupports2(name: *const nsACString_internal,
                               value: *const nsACString_internal) -> bool;
 }
diff --git a/components/style/gecko_bindings/sugar/ns_css_value.rs b/components/style/gecko_bindings/sugar/ns_css_value.rs
index 3f125b13311..0eb9dc5c90c 100644
--- a/components/style/gecko_bindings/sugar/ns_css_value.rs
+++ b/components/style/gecko_bindings/sugar/ns_css_value.rs
@@ -12,7 +12,7 @@ use gecko_bindings::bindings::Gecko_CSSValue_GetPercentage;
 use gecko_bindings::bindings::Gecko_CSSValue_SetAbsoluteLength;
 use gecko_bindings::bindings::Gecko_CSSValue_SetCalc;
 use gecko_bindings::bindings::Gecko_CSSValue_SetPercentage;
-use gecko_bindings::structs::{nsCSSValue, nsCSSUnit, nsCSSValue_Array};
+use gecko_bindings::structs::{nsCSSValue, nsCSSUnit, nsCSSValue_Array, nscolor};
 use std::mem;
 use std::ops::Index;
 use std::slice;
@@ -34,6 +34,28 @@ impl nsCSSValue {
         unsafe { *self.mValue.mInt.as_ref() }
     }
 
+    /// Checks if it is an integer and returns it if so
+    pub fn integer(&self) -> Option<i32> {
+        if self.mUnit == nsCSSUnit::eCSSUnit_Integer ||
+           self.mUnit == nsCSSUnit::eCSSUnit_Enumerated ||
+           self.mUnit == nsCSSUnit::eCSSUnit_EnumColor {
+            Some(unsafe { *self.mValue.mInt.as_ref() })
+        } else {
+            None
+        }
+    }
+
+    /// Checks if it is an RGBA color, returning it if so
+    /// Only use it with colors set by SetColorValue(),
+    /// which always sets RGBA colors
+    pub fn color_value(&self) -> Option<nscolor> {
+        if self.mUnit == nsCSSUnit::eCSSUnit_RGBAColor {
+            Some(unsafe { *self.mValue.mColor.as_ref() })
+        } else {
+            None
+        }
+    }
+
     /// Returns this nsCSSValue value as a floating point value, unchecked in
     /// release builds.
     pub fn float_unchecked(&self) -> f32 {
diff --git a/components/style/values/specified/length.rs b/components/style/values/specified/length.rs
index 9cc284fd774..351c692cc9a 100644
--- a/components/style/values/specified/length.rs
+++ b/components/style/values/specified/length.rs
@@ -293,6 +293,20 @@ impl NoCalcLength {
         })
     }
 
+    /// https://drafts.csswg.org/css-fonts-3/#font-size-prop
+    pub fn from_font_size_int(i: u8) -> Self {
+        let au = match i {
+            0 | 1 => Au::from_px(FONT_MEDIUM_PX) * 3 / 4,
+            2 => Au::from_px(FONT_MEDIUM_PX) * 8 / 9,
+            3 => Au::from_px(FONT_MEDIUM_PX),
+            4 => Au::from_px(FONT_MEDIUM_PX) * 6 / 5,
+            5 => Au::from_px(FONT_MEDIUM_PX) * 3 / 2,
+            6 => Au::from_px(FONT_MEDIUM_PX) * 2,
+            _ => Au::from_px(FONT_MEDIUM_PX) * 3,
+        };
+        NoCalcLength::Absolute(au)
+    }
+
     /// Parse a given absolute or relative dimension.
     pub fn parse_dimension(value: CSSFloat, unit: &str) -> Result<NoCalcLength, ()> {
         match_ignore_ascii_case! { unit,
@@ -429,6 +443,11 @@ impl Length {
         NoCalcLength::parse_dimension(value, unit).map(Length::NoCalc)
     }
 
+    /// https://drafts.csswg.org/css-fonts-3/#font-size-prop
+    pub fn from_font_size_int(i: u8) -> Self {
+        Length::NoCalc(NoCalcLength::from_font_size_int(i))
+    }
+
     #[inline]
     fn parse_internal(input: &mut Parser, context: AllowedNumericType) -> Result<Length, ()> {
         match try!(input.next()) {
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 5de30623403..e075843a114 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -34,7 +34,7 @@ use style::gecko_bindings::bindings::{RawServoStyleSetBorrowed, RawServoStyleSet
 use style::gecko_bindings::bindings::{RawServoStyleSheetBorrowed, ServoComputedValuesBorrowed};
 use style::gecko_bindings::bindings::{RawServoStyleSheetStrong, ServoComputedValuesStrong};
 use style::gecko_bindings::bindings::{ServoCssRulesBorrowed, ServoCssRulesStrong};
-use style::gecko_bindings::bindings::{nsACString, nsAString};
+use style::gecko_bindings::bindings::{nsACString, nsCSSValueBorrowedMut, nsAString};
 use style::gecko_bindings::bindings::Gecko_AnimationAppendKeyframe;
 use style::gecko_bindings::bindings::RawGeckoAnimationValueListBorrowedMut;
 use style::gecko_bindings::bindings::RawGeckoElementBorrowed;
@@ -947,6 +947,61 @@ pub extern "C" fn Servo_DeclarationBlock_RemovePropertyById(declarations: RawSer
 }
 
 #[no_mangle]
+pub extern "C" fn Servo_DeclarationBlock_AddPresValue(declarations: RawServoDeclarationBlockBorrowed,
+                                                      property: nsCSSPropertyID,
+                                                      css_value: nsCSSValueBorrowedMut) {
+    use style::gecko::values::convert_nscolor_to_rgba;
+    use style::properties::{DeclaredValue, LonghandId, PropertyDeclaration, PropertyId, longhands};
+    use style::values::specified;
+
+    let declarations = RwLock::<PropertyDeclarationBlock>::as_arc(&declarations);
+    let prop = PropertyId::from_nscsspropertyid(property);
+
+    let long = match prop {
+        Ok(PropertyId::Longhand(long)) => long,
+        _ => {
+            error!("stylo: unknown presentation property with id {:?}", property);
+            return
+        }
+    };
+    let decl = match long {
+        LonghandId::FontSize => {
+            if let Some(int) = css_value.integer() {
+                PropertyDeclaration::FontSize(DeclaredValue::Value(
+                    longhands::font_size::SpecifiedValue(
+                        specified::LengthOrPercentage::Length(
+                            specified::NoCalcLength::from_font_size_int(int as u8)
+                        )
+                    )
+                ))
+            } else {
+                error!("stylo: got unexpected non-integer value for font-size presentation attribute");
+                return
+            }
+        }
+        LonghandId::Color => {
+            if let Some(color) = css_value.color_value() {
+                PropertyDeclaration::Color(DeclaredValue::Value(
+                    specified::CSSRGBA {
+                        parsed: convert_nscolor_to_rgba(color),
+                        authored: None
+                    }
+                ))
+            } else {
+                error!("stylo: got unexpected non-integer value for color presentation attribute");
+                return
+            }
+        }
+        _ => {
+            error!("stylo: cannot handle longhand {:?} from presentation attribute", long);
+            return
+        }
+    };
+    declarations.write().declarations.push((decl, Importance::Normal));
+
+}
+
+#[no_mangle]
 pub extern "C" fn Servo_CSSSupports2(property: *const nsACString, value: *const nsACString) -> bool {
     let property = unsafe { property.as_ref().unwrap().as_str_unchecked() };
     let id =  if let Ok(id) = PropertyId::parse(property.into()) {