Auto merge of #16625 - birtles:smil-support, r=hiro,heycam

SMIL support for Gecko

PR for [Gecko bug 1355348](https://bugzilla.mozilla.org/show_bug.cgi?id=1355348)

---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because they are tested on the Gecko side

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---
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components/style/dom.rs

@@ -319,6 +319,11 @@ pub trait TElement : Eq + PartialEq + Debug + Hash + Sized + Copy + Clone +
     /// Get this element's style attribute.
     fn style_attribute(&self) -> Option<&Arc<Locked<PropertyDeclarationBlock>>>;
 
+    /// Get this element's SMIL override declarations.
+    fn get_smil_override(&self) -> Option<&Arc<Locked<PropertyDeclarationBlock>>> {
+        None
+    }
+
     /// Get this element's animation rules.
     fn get_animation_rules(&self, _pseudo: Option<&PseudoElement>) -> AnimationRules {
         AnimationRules(None, None)

components/style/gecko/wrapper.rs

@@ -38,6 +38,7 @@ use gecko_bindings::bindings::Gecko_ElementHasCSSTransitions;
 use gecko_bindings::bindings::Gecko_GetAnimationRule;
 use gecko_bindings::bindings::Gecko_GetExtraContentStyleDeclarations;
 use gecko_bindings::bindings::Gecko_GetHTMLPresentationAttrDeclarationBlock;
+use gecko_bindings::bindings::Gecko_GetSMILOverrideDeclarationBlock;
 use gecko_bindings::bindings::Gecko_GetStyleAttrDeclarationBlock;
 use gecko_bindings::bindings::Gecko_GetStyleContext;
 use gecko_bindings::bindings::Gecko_IsSignificantChild;
@@ -525,6 +526,11 @@ impl<'le> TElement for GeckoElement<'le> {
         declarations.map(|s| s.as_arc_opt()).unwrap_or(None)
     }
 
+    fn get_smil_override(&self) -> Option<&Arc<Locked<PropertyDeclarationBlock>>> {
+        let declarations = unsafe { Gecko_GetSMILOverrideDeclarationBlock(self.0) };
+        declarations.map(|s| s.as_arc_opt()).unwrap_or(None)
+    }
+
     fn get_animation_rules(&self, pseudo: Option<&PseudoElement>) -> AnimationRules {
         AnimationRules(self.get_animation_rule(pseudo),
                        self.get_transition_rule(pseudo))

components/style/gecko_bindings/bindings.rs

@@ -623,6 +623,11 @@ extern "C" {
                                       RawServoAnimationValueMapBorrowed)
      -> bool;
 }
+extern "C" {
+    pub fn Gecko_GetSMILOverrideDeclarationBlock(element:
+                                                     RawGeckoElementBorrowed)
+     -> RawServoDeclarationBlockStrongBorrowedOrNull;
+}
 extern "C" {
     pub fn Gecko_StyleAnimationsEquals(arg1:
                                            RawGeckoStyleAnimationListBorrowed,

components/style/matching.rs

@@ -19,7 +19,8 @@ use dom::{AnimationRules, SendElement, TElement, TNode};
 use font_metrics::FontMetricsProvider;
 use properties::{CascadeFlags, ComputedValues, SKIP_ROOT_AND_ITEM_BASED_DISPLAY_FIXUP, cascade};
 use properties::longhands::display::computed_value as display;
-use restyle_hints::{RESTYLE_STYLE_ATTRIBUTE, RESTYLE_CSS_ANIMATIONS, RESTYLE_CSS_TRANSITIONS, RestyleHint};
+use restyle_hints::{RESTYLE_CSS_ANIMATIONS, RESTYLE_CSS_TRANSITIONS, RestyleHint};
+use restyle_hints::{RESTYLE_STYLE_ATTRIBUTE, RESTYLE_SMIL};
 use rule_tree::{CascadeLevel, RuleTree, StrongRuleNode};
 use selector_parser::{PseudoElement, RestyleDamage, SelectorImpl};
 use selectors::bloom::BloomFilter;
@@ -882,6 +883,7 @@ pub trait MatchMethods : TElement {
 
         let stylist = &context.shared.stylist;
         let style_attribute = self.style_attribute();
+        let smil_override = self.get_smil_override();
         let animation_rules = self.get_animation_rules(None);
         let mut rule_nodes_changed = false;
         let bloom = context.thread_local.bloom_filter.filter();
@@ -895,6 +897,7 @@ pub trait MatchMethods : TElement {
         *relations = stylist.push_applicable_declarations(self,
                                                           Some(bloom),
                                                           style_attribute,
+                                                          smil_override,
                                                           animation_rules,
                                                           None,
                                                           &context.shared.guards,
@@ -952,7 +955,9 @@ pub trait MatchMethods : TElement {
             };
             stylist.push_applicable_declarations(self,
                                                  Some(bloom_filter),
-                                                 None, pseudo_animation_rules,
+                                                 None,
+                                                 None,
+                                                 pseudo_animation_rules,
                                                  Some(&pseudo),
                                                  &guards,
                                                  &mut applicable_declarations,
@@ -1068,12 +1073,18 @@ pub trait MatchMethods : TElement {
                 }
             };
 
-            // RESTYLE_CSS_ANIMATIONS or RESTYLE_CSS_TRANSITIONS is processed prior to other
+            // Animation restyle hints are processed prior to other restyle hints in the
-            // restyle hints in the name of animation-only traversal. Rest of restyle hints
+            // animation-only traversal. Non-animation restyle hints will be processed in
-            // will be processed in a subsequent normal traversal.
+            // a subsequent normal traversal.
             if hint.intersects(RestyleHint::for_animations()) {
                 debug_assert!(context.shared.traversal_flags.for_animation_only());
 
+                if hint.contains(RESTYLE_SMIL) {
+                    replace_rule_node(CascadeLevel::SMILOverride,
+                                      self.get_smil_override(),
+                                      primary_rules);
+                }
+
                 use data::EagerPseudoStyles;
                 let mut replace_rule_node_for_animation = |level: CascadeLevel,
                                                            primary_rules: &mut StrongRuleNode,
@@ -1330,7 +1341,7 @@ pub trait MatchMethods : TElement {
         let relevant_style = pseudo_style.unwrap_or(primary_style);
         let rule_node = &relevant_style.rules;
         let without_animation_rules =
-            shared_context.stylist.rule_tree.remove_animation_and_transition_rules(rule_node);
+            shared_context.stylist.rule_tree.remove_animation_rules(rule_node);
         if without_animation_rules == *rule_node {
             // Note that unwrapping here is fine, because the style is
             // only incomplete during the styling process.

components/style/restyle_hints.rs

@@ -62,6 +62,11 @@ bitflags! {
         /// attribute has changed, and this change didn't have any other
         /// dependencies.
         const RESTYLE_STYLE_ATTRIBUTE = 0x40,
+
+        /// Replace the style data coming from SMIL animations without updating
+        /// any other style data. This hint is only processed in animation-only
+        /// traversal which is prior to normal traversal.
+        const RESTYLE_SMIL = 0x80,
     }
 }
 
@@ -95,19 +100,22 @@ pub fn assert_restyle_hints_match() {
         nsRestyleHint_eRestyle_CSSTransitions => RESTYLE_CSS_TRANSITIONS,
         nsRestyleHint_eRestyle_CSSAnimations => RESTYLE_CSS_ANIMATIONS,
         nsRestyleHint_eRestyle_StyleAttribute => RESTYLE_STYLE_ATTRIBUTE,
+        nsRestyleHint_eRestyle_StyleAttribute_Animations => RESTYLE_SMIL,
     }
 }
 
 impl RestyleHint {
     /// The subset hints that affect the styling of a single element during the
     /// traversal.
+    #[inline]
     pub fn for_self() -> Self {
-        RESTYLE_SELF | RESTYLE_STYLE_ATTRIBUTE | RESTYLE_CSS_ANIMATIONS | RESTYLE_CSS_TRANSITIONS
+        RESTYLE_SELF | RESTYLE_STYLE_ATTRIBUTE | Self::for_animations()
     }
 
     /// The subset hints that are used for animation restyle.
+    #[inline]
     pub fn for_animations() -> Self {
-        RESTYLE_CSS_ANIMATIONS | RESTYLE_CSS_TRANSITIONS
+        RESTYLE_SMIL | RESTYLE_CSS_ANIMATIONS | RESTYLE_CSS_TRANSITIONS
     }
 }
 

components/style/rule_tree/mod.rs

@@ -254,19 +254,19 @@ impl RuleTree {
         path.parent().unwrap().clone()
     }
 
-    /// Returns new rule node without Animations and Transitions level rules.
+    /// Returns new rule node without rules from declarative animations.
-    pub fn remove_animation_and_transition_rules(&self, path: &StrongRuleNode) -> StrongRuleNode {
+    pub fn remove_animation_rules(&self, path: &StrongRuleNode) -> StrongRuleNode {
-        // Return a clone if there is neither animation nor transition level.
+        // Return a clone if there are no animation rules.
         if !path.has_animation_or_transition_rules() {
             return path.clone();
         }
 
-        let iter = path.self_and_ancestors().take_while(|node| node.cascade_level() >= CascadeLevel::Animations);
+        let iter = path.self_and_ancestors().take_while(
+            |node| node.cascade_level() >= CascadeLevel::SMILOverride);
         let mut last = path;
         let mut children = vec![];
         for node in iter {
-            if node.cascade_level() != CascadeLevel::Animations &&
+            if node.cascade_level().is_animation() {
-               node.cascade_level() != CascadeLevel::Transitions {
                 children.push((node.get().source.clone().unwrap(), node.cascade_level()));
             }
             last = node;
@@ -301,6 +301,8 @@ pub enum CascadeLevel {
     AuthorNormal,
     /// Style attribute normal rules.
     StyleAttributeNormal,
+    /// SVG SMIL animations.
+    SMILOverride,
     /// CSS animations and script-generated animations.
     Animations,
     /// Author-supplied important rules.
@@ -333,6 +335,7 @@ impl CascadeLevel {
         match *self {
             CascadeLevel::Transitions |
             CascadeLevel::Animations |
+            CascadeLevel::SMILOverride |
             CascadeLevel::StyleAttributeNormal |
             CascadeLevel::StyleAttributeImportant => true,
             _ => false,
@@ -362,6 +365,17 @@ impl CascadeLevel {
             Importance::Normal
         }
     }
+
+    /// Returns whether this cascade level represents an animation rules.
+    #[inline]
+    pub fn is_animation(&self) -> bool {
+        match *self {
+            CascadeLevel::SMILOverride |
+            CascadeLevel::Animations |
+            CascadeLevel::Transitions => true,
+            _ => false,
+        }
+    }
 }
 
 struct RuleNode {
@@ -780,8 +794,8 @@ impl StrongRuleNode {
     /// Returns true if there is either animation or transition level rule.
     pub fn has_animation_or_transition_rules(&self) -> bool {
         self.self_and_ancestors()
-            .take_while(|node| node.cascade_level() >= CascadeLevel::Animations)
+            .take_while(|node| node.cascade_level() >= CascadeLevel::SMILOverride)
-            .any(|node| matches!(node.cascade_level(), CascadeLevel::Animations | CascadeLevel::Transitions))
+            .any(|node| node.cascade_level().is_animation())
     }
 }
 

components/style/stylist.rs

@@ -510,6 +510,7 @@ impl Stylist {
 
 
         self.push_applicable_declarations(element,
+                                          None,
                                           None,
                                           None,
                                           AnimationRules(None, None),
@@ -631,6 +632,7 @@ impl Stylist {
                                         element: &E,
                                         parent_bf: Option<&BloomFilter>,
                                         style_attribute: Option<&Arc<Locked<PropertyDeclarationBlock>>>,
+                                        smil_override: Option<&Arc<Locked<PropertyDeclarationBlock>>>,
                                         animation_rules: AnimationRules,
                                         pseudo_element: Option<&PseudoElement>,
                                         guards: &StylesheetGuards,
@@ -711,7 +713,17 @@ impl Stylist {
 
             debug!("style attr: {:?}", relations);
 
-            // Step 5: Animations.
+            // Step 5: SMIL override.
+            // Declarations from SVG SMIL animation elements.
+            if let Some(so) = smil_override {
+                Push::push(
+                    applicable_declarations,
+                    ApplicableDeclarationBlock::from_declarations(so.clone(),
+                                                                  CascadeLevel::SMILOverride));
+            }
+            debug!("SMIL: {:?}", relations);
+
+            // Step 6: Animations.
             // The animations sheet (CSS animations, script-generated animations,
             // and CSS transitions that are no longer tied to CSS markup)
             if let Some(anim) = animation_rules.0 {
@@ -722,7 +734,7 @@ impl Stylist {
             }
             debug!("animation: {:?}", relations);
 
-            // Step 6: Author-supplied `!important` rules.
+            // Step 7: Author-supplied `!important` rules.
             map.author.get_all_matching_rules(element,
                                               parent_bf,
                                               applicable_declarations,
@@ -732,7 +744,7 @@ impl Stylist {
 
             debug!("author important: {:?}", relations);
 
-            // Step 7: `!important` style attributes.
+            // Step 8: `!important` style attributes.
             if let Some(sa) = style_attribute {
                 if sa.read_with(guards.author).any_important() {
                     relations |= AFFECTED_BY_STYLE_ATTRIBUTE;
@@ -745,7 +757,7 @@ impl Stylist {
 
             debug!("style attr important: {:?}", relations);
 
-            // Step 8: User `!important` rules.
+            // Step 9: User `!important` rules.
             map.user.get_all_matching_rules(element,
                                             parent_bf,
                                             applicable_declarations,
@@ -758,7 +770,7 @@ impl Stylist {
             debug!("skipping non-agent rules");
         }
 
-        // Step 9: UA `!important` rules.
+        // Step 10: UA `!important` rules.
         map.user_agent.get_all_matching_rules(element,
                                               parent_bf,
                                               applicable_declarations,
@@ -768,7 +780,7 @@ impl Stylist {
 
         debug!("UA important: {:?}", relations);
 
-        // Step 10: Transitions.
+        // Step 11: Transitions.
         // The transitions sheet (CSS transitions that are tied to CSS markup)
         if let Some(anim) = animation_rules.1 {
             Push::push(

ports/geckolib/glue.rs

@@ -1795,19 +1795,17 @@ pub extern "C" fn Servo_NoteExplicitHints(element: RawGeckoElementBorrowed,
     let damage = GeckoRestyleDamage::new(change_hint);
     debug!("Servo_NoteExplicitHints: {:?}, restyle_hint={:?}, change_hint={:?}",
            element, restyle_hint, change_hint);
-    debug_assert!(restyle_hint == structs::nsRestyleHint_eRestyle_CSSAnimations ||
+
-                  restyle_hint == structs::nsRestyleHint_eRestyle_CSSTransitions ||
+    let restyle_hint: RestyleHint = restyle_hint.into();
-                  (restyle_hint.0 & (structs::nsRestyleHint_eRestyle_CSSAnimations.0 |
+    debug_assert!(RestyleHint::for_animations().contains(restyle_hint) ||
-                                     structs::nsRestyleHint_eRestyle_CSSTransitions.0)) == 0,
+                  !RestyleHint::for_animations().intersects(restyle_hint),
-                  "eRestyle_CSSAnimations or eRestyle_CSSTransitions should only appear by itself");
+                  "Animation restyle hints should not appear with non-animation restyle hints");
 
     let mut maybe_data = element.mutate_data();
     let maybe_restyle_data = maybe_data.as_mut().and_then(|d| unsafe {
-        maybe_restyle(d, element, restyle_hint == structs::nsRestyleHint_eRestyle_CSSAnimations ||
+        maybe_restyle(d, element, restyle_hint.intersects(RestyleHint::for_animations()))
-                                  restyle_hint == structs::nsRestyleHint_eRestyle_CSSTransitions)
     });
     if let Some(restyle_data) = maybe_restyle_data {
-        let restyle_hint: RestyleHint = restyle_hint.into();
         restyle_data.hint.insert(&restyle_hint.into());
         restyle_data.damage |= damage;
     } else {