servo: Merge #15175 - Interpolate servo animation values and add them to the cascade (from BorisChiou:animation/interpolate_and_cascade); r=heycam

These are the servo-side changes for [bug 1317209](https://bugzilla.mozilla.org/show_bug.cgi?id=1317209). @Manishearth, @emilio, and @heycam have already reviewed them there. Please merge these patches until the gecko-side changes for [bug 1317209](https://bugzilla.mozilla.org/show_bug.cgi?id=1317209) is landed.

---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix [bug 1317209](https://bugzilla.mozilla.org/show_bug.cgi?id=1317209).
- [X] These changes do not require tests because there are existing tests for this in mozilla-central

Source-Repo: https://github.com/servo/servo
Source-Revision: e4a1cb6f87ac1ba2035c833dca5d9619edeefb8d

servo/components/style/build_gecko.rs

@@ -491,6 +491,7 @@ mod bindings {
             "RawGeckoNode",
             "RawGeckoAnimationValueList",
             "RawServoAnimationValue",
+            "RawServoAnimationValueList",
             "RawGeckoPresContext",
             "RawGeckoPresContextOwned",
             "ThreadSafeURIHolder",
@@ -593,6 +594,7 @@ mod bindings {
         let servo_borrow_types = [
             "nsCSSValue",
             "RawGeckoAnimationValueList",
+            "RawServoAnimationValueList",
         ];
         for &ty in structs_types.iter() {
             builder = builder.hide_type(ty)

servo/components/style/dom.rs

@@ -227,6 +227,11 @@ pub trait PresentationalHintsSynthetizer {
         where V: Push<ApplicableDeclarationBlock>;
 }
 
+/// The animation rules. The first one is for Animation cascade level, and the second one is for
+/// Transition cascade level.
+pub struct AnimationRules(pub Option<Arc<RwLock<PropertyDeclarationBlock>>>,
+                          pub Option<Arc<RwLock<PropertyDeclarationBlock>>>);
+
 /// The element trait, the main abstraction the style crate acts over.
 pub trait TElement : PartialEq + Debug + Sized + Copy + Clone + ElementExt + PresentationalHintsSynthetizer {
     /// The concrete node type.
@@ -248,6 +253,11 @@ pub trait TElement : PartialEq + Debug + Sized + Copy + Clone + ElementExt + Pre
     /// Get this element's style attribute.
     fn style_attribute(&self) -> Option<&Arc<RwLock<PropertyDeclarationBlock>>>;
 
+    /// Get this element's animation rules.
+    fn get_animation_rules(&self, _pseudo: Option<&PseudoElement>) -> AnimationRules {
+        AnimationRules(None, None)
+    }
+
     /// Get this element's state, for non-tree-structural pseudos.
     fn get_state(&self) -> ElementState;
 

servo/components/style/gecko/wrapper.rs

@@ -16,7 +16,7 @@
 
 use atomic_refcell::AtomicRefCell;
 use data::ElementData;
-use dom::{LayoutIterator, NodeInfo, TElement, TNode, UnsafeNode};
+use dom::{AnimationRules, LayoutIterator, NodeInfo, TElement, TNode, UnsafeNode};
 use dom::{OpaqueNode, PresentationalHintsSynthetizer};
 use element_state::ElementState;
 use error_reporting::StdoutErrorReporter;
@@ -30,10 +30,12 @@ use gecko_bindings::bindings::{Gecko_IsLink, Gecko_IsRootElement, Gecko_MatchesE
 use gecko_bindings::bindings::{Gecko_IsUnvisitedLink, Gecko_IsVisitedLink, Gecko_Namespace};
 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_GetStyleContext;
 use gecko_bindings::structs;
 use gecko_bindings::structs::{RawGeckoElement, RawGeckoNode};
 use gecko_bindings::structs::{nsIAtom, nsIContent, nsStyleContext};
+use gecko_bindings::structs::EffectCompositor_CascadeLevel as CascadeLevel;
 use gecko_bindings::structs::NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO;
 use gecko_bindings::structs::NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE;
 use parking_lot::RwLock;
@@ -335,6 +337,15 @@ impl<'le> TElement for GeckoElement<'le> {
         declarations.map(|s| s.as_arc_opt()).unwrap_or(None)
     }
 
+    fn get_animation_rules(&self, pseudo: Option<&PseudoElement>) -> AnimationRules {
+        let atom_ptr = pseudo.map(|p| p.as_atom().as_ptr()).unwrap_or(ptr::null_mut());
+        unsafe {
+            AnimationRules(
+                Gecko_GetAnimationRule(self.0, atom_ptr, CascadeLevel::Animations).into_arc_opt(),
+                Gecko_GetAnimationRule(self.0, atom_ptr, CascadeLevel::Transitions).into_arc_opt())
+        }
+    }
+
     fn get_state(&self) -> ElementState {
         unsafe {
             ElementState::from_bits_truncate(Gecko_ElementState(self.0))

servo/components/style/gecko_bindings/bindings.rs

@@ -3,11 +3,13 @@
 pub use nsstring::{nsACString, nsAString};
 type nsACString_internal = nsACString;
 type nsAString_internal = nsAString;
+use gecko_bindings::structs::EffectCompositor_CascadeLevel;
 use gecko_bindings::structs::RawGeckoDocument;
 use gecko_bindings::structs::RawGeckoElement;
 use gecko_bindings::structs::RawGeckoNode;
 use gecko_bindings::structs::RawGeckoAnimationValueList;
 use gecko_bindings::structs::RawServoAnimationValue;
+use gecko_bindings::structs::RawServoAnimationValueBorrowedList;
 use gecko_bindings::structs::RawGeckoPresContext;
 use gecko_bindings::structs::RawGeckoPresContextOwned;
 use gecko_bindings::structs::ThreadSafeURIHolder;
@@ -224,6 +226,8 @@ pub type RawGeckoAnimationValueListBorrowed<'a> = &'a RawGeckoAnimationValueList
 pub type RawGeckoAnimationValueListBorrowedOrNull<'a> = Option<&'a RawGeckoAnimationValueList>;
 pub type RawGeckoAnimationValueListBorrowedMut<'a> = &'a mut RawGeckoAnimationValueList;
 pub type RawGeckoAnimationValueListBorrowedMutOrNull<'a> = Option<&'a mut RawGeckoAnimationValueList>;
+pub type RawServoAnimationValueBorrowedListBorrowed<'a> = &'a RawServoAnimationValueBorrowedList;
+pub type RawServoAnimationValueBorrowedListBorrowedOrNull<'a> = Option<&'a RawServoAnimationValueBorrowedList>;
 
 extern "C" {
     pub fn Gecko_EnsureTArrayCapacity(aArray: *mut ::std::os::raw::c_void,
@@ -498,6 +502,12 @@ extern "C" {
     pub fn Gecko_GetServoDeclarationBlock(element: RawGeckoElementBorrowed)
      -> RawServoDeclarationBlockStrongBorrowedOrNull;
 }
+extern "C" {
+    pub fn Gecko_GetAnimationRule(element: RawGeckoElementBorrowed,
+                                  aAtom: *mut nsIAtom,
+                                  aCascadeLevel: EffectCompositor_CascadeLevel)
+     -> RawServoDeclarationBlockStrong;
+}
 extern "C" {
     pub fn Gecko_Atomize(aString: *const ::std::os::raw::c_char, aLength: u32)
      -> *mut nsIAtom;
@@ -1217,6 +1227,16 @@ extern "C" {
                                                  ServoComputedValuesBorrowed)
      -> ServoComputedValuesStrong;
 }
+extern "C" {
+    pub fn Servo_AnimationValues_Interpolate(from: RawServoAnimationValueBorrowed,
+                                             to: RawServoAnimationValueBorrowed,
+                                             progress: f64)
+     -> RawServoAnimationValueStrong;
+}
+extern "C" {
+    pub fn Servo_AnimationValues_Uncompute(value: RawServoAnimationValueBorrowedListBorrowed)
+     -> RawServoDeclarationBlockStrong;
+}
 extern "C" {
     pub fn Servo_AnimationValues_Populate(arg1:
                                               RawGeckoAnimationValueListBorrowedMut,

servo/components/style/gecko_bindings/structs_debug.rs

@@ -5273,6 +5273,12 @@ pub mod root {
         impl Clone for StyleComplexColor {
             fn clone(&self) -> Self { *self }
         }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum EffectCompositor_CascadeLevel {
+            Animations = 0,
+            Transitions = 1,
+        }
         #[repr(C)]
         #[derive(Debug)]
         pub struct PropertyStyleAnimationValuePair {
@@ -17953,6 +17959,10 @@ pub mod root {
     pub type RawGeckoPresContextBorrowedMut = *mut root::RawGeckoPresContext;
     pub type RawGeckoAnimationValueListBorrowedMut =
         *mut root::RawGeckoAnimationValueList;
+    pub type RawServoAnimationValueBorrowedList =
+        root::nsTArray<*const root::RawServoAnimationValue>;
+    pub type RawServoAnimationValueBorrowedListBorrowed =
+        *const root::RawServoAnimationValueBorrowedList;
     #[repr(u32)]
     #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
     pub enum nsCSSTokenSerializationType {

servo/components/style/gecko_bindings/structs_release.rs

@@ -5191,6 +5191,12 @@ pub mod root {
         impl Clone for StyleComplexColor {
             fn clone(&self) -> Self { *self }
         }
+        #[repr(u32)]
+        #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+        pub enum EffectCompositor_CascadeLevel {
+            Animations = 0,
+            Transitions = 1,
+        }
         #[repr(C)]
         #[derive(Debug)]
         pub struct PropertyStyleAnimationValuePair {
@@ -17726,6 +17732,10 @@ pub mod root {
     pub type RawGeckoPresContextBorrowedMut = *mut root::RawGeckoPresContext;
     pub type RawGeckoAnimationValueListBorrowedMut =
         *mut root::RawGeckoAnimationValueList;
+    pub type RawServoAnimationValueBorrowedList =
+        root::nsTArray<*const root::RawServoAnimationValue>;
+    pub type RawServoAnimationValueBorrowedListBorrowed =
+        *const root::RawServoAnimationValueBorrowedList;
     #[repr(u32)]
     #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
     pub enum nsCSSTokenSerializationType {

servo/components/style/matching.rs

@@ -589,12 +589,14 @@ pub trait MatchMethods : TElement {
         let mut applicable_declarations: Vec<ApplicableDeclarationBlock> = Vec::with_capacity(16);
         let stylist = &context.shared.stylist;
         let style_attribute = self.style_attribute();
+        let animation_rules = self.get_animation_rules(None);
 
         // Compute the primary rule node.
         let mut primary_relations =
             stylist.push_applicable_declarations(self,
                                                  parent_bf,
                                                  style_attribute,
+                                                 animation_rules,
                                                  None,
                                                  &mut applicable_declarations,
                                                  MatchingReason::ForStyling);
@@ -604,7 +606,9 @@ pub trait MatchMethods : TElement {
         let mut per_pseudo: PseudoRuleNodes = HashMap::with_hasher(Default::default());
         SelectorImpl::each_eagerly_cascaded_pseudo_element(|pseudo| {
             debug_assert!(applicable_declarations.is_empty());
+            let pseudo_animation_rules = self.get_animation_rules(Some(&pseudo));
             stylist.push_applicable_declarations(self, parent_bf, None,
+                                                 pseudo_animation_rules,
                                                  Some(&pseudo.clone()),
                                                  &mut applicable_declarations,
                                                  MatchingReason::ForStyling);

servo/components/style/stylist.rs

@@ -8,7 +8,7 @@
 
 use {Atom, LocalName};
 use data::ComputedStyle;
-use dom::{PresentationalHintsSynthetizer, TElement};
+use dom::{AnimationRules, PresentationalHintsSynthetizer, TElement};
 use error_reporting::StdoutErrorReporter;
 use keyframes::KeyframesAnimation;
 use media_queries::Device;
@@ -21,6 +21,7 @@ use rule_tree::{RuleTree, StrongRuleNode, StyleSource};
 use selector_parser::{ElementExt, SelectorImpl, PseudoElement, Snapshot};
 use selectors::Element;
 use selectors::bloom::BloomFilter;
+use selectors::matching::{AFFECTED_BY_ANIMATIONS, AFFECTED_BY_TRANSITIONS};
 use selectors::matching::{AFFECTED_BY_STYLE_ATTRIBUTE, AFFECTED_BY_PRESENTATIONAL_HINTS};
 use selectors::matching::{MatchingReason, StyleRelations, matches_complex_selector};
 use selectors::parser::{Selector, SimpleSelector, LocalName as LocalNameSelector, ComplexSelector};
@@ -386,6 +387,7 @@ impl Stylist {
         self.push_applicable_declarations(element,
                                           None,
                                           None,
+                                          AnimationRules(None, None),
                                           Some(pseudo),
                                           &mut declarations,
                                           MatchingReason::ForStyling);
@@ -490,6 +492,7 @@ impl Stylist {
                                         element: &E,
                                         parent_bf: Option<&BloomFilter>,
                                         style_attribute: Option<&Arc<RwLock<PropertyDeclarationBlock>>>,
+                                        animation_rules: AnimationRules,
                                         pseudo_element: Option<&PseudoElement>,
                                         applicable_declarations: &mut V,
                                         reason: MatchingReason) -> StyleRelations
@@ -560,7 +563,18 @@ impl Stylist {
 
             debug!("style attr: {:?}", relations);
 
-            // Step 5: Author-supplied `!important` rules.
+            // Step 5: 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 {
+                relations |= AFFECTED_BY_ANIMATIONS;
+                Push::push(
+                    applicable_declarations,
+                    ApplicableDeclarationBlock::from_declarations(anim.clone(), Importance::Normal));
+            }
+            debug!("animation: {:?}", relations);
+
+            // Step 6: Author-supplied `!important` rules.
             map.author.get_all_matching_rules(element,
                                               parent_bf,
                                               applicable_declarations,
@@ -570,7 +584,7 @@ impl Stylist {
 
             debug!("author important: {:?}", relations);
 
-            // Step 6: `!important` style attributes.
+            // Step 7: `!important` style attributes.
             if let Some(sa) = style_attribute {
                 if sa.read().any_important() {
                     relations |= AFFECTED_BY_STYLE_ATTRIBUTE;
@@ -582,7 +596,7 @@ impl Stylist {
 
             debug!("style attr important: {:?}", relations);
 
-            // Step 7: User `!important` rules.
+            // Step 8: User `!important` rules.
             map.user.get_all_matching_rules(element,
                                             parent_bf,
                                             applicable_declarations,
@@ -595,7 +609,7 @@ impl Stylist {
             debug!("skipping non-agent rules");
         }
 
-        // Step 8: UA `!important` rules.
+        // Step 9: UA `!important` rules.
         map.user_agent.get_all_matching_rules(element,
                                               parent_bf,
                                               applicable_declarations,
@@ -605,6 +619,16 @@ impl Stylist {
 
         debug!("UA important: {:?}", relations);
 
+        // Step 10: Transitions.
+        // The transitions sheet (CSS transitions that are tied to CSS markup)
+        if let Some(anim) = animation_rules.1 {
+            relations |= AFFECTED_BY_TRANSITIONS;
+            Push::push(
+                applicable_declarations,
+                ApplicableDeclarationBlock::from_declarations(anim.clone(), Importance::Normal));
+        }
+        debug!("transition: {:?}", relations);
+
         debug!("push_applicable_declarations: shareable: {:?}", relations);
 
         relations

servo/ports/geckolib/glue.rs

@@ -39,6 +39,8 @@ use style::gecko_bindings::bindings::RawGeckoAnimationValueListBorrowedMut;
 use style::gecko_bindings::bindings::RawGeckoElementBorrowed;
 use style::gecko_bindings::bindings::RawGeckoPresContextBorrowed;
 use style::gecko_bindings::bindings::RawServoAnimationValueBorrowed;
+use style::gecko_bindings::bindings::RawServoAnimationValueBorrowedListBorrowed;
+use style::gecko_bindings::bindings::RawServoAnimationValueStrong;
 use style::gecko_bindings::bindings::RawServoImportRuleBorrowed;
 use style::gecko_bindings::bindings::ServoComputedValuesBorrowedOrNull;
 use style::gecko_bindings::bindings::nsTArrayBorrowed_uintptr_t;
@@ -58,7 +60,7 @@ use style::parser::{ParserContext, ParserContextExtraData};
 use style::properties::{CascadeFlags, ComputedValues, Importance, PropertyDeclaration};
 use style::properties::{PropertyDeclarationParseResult, PropertyDeclarationBlock, PropertyId};
 use style::properties::{apply_declarations, parse_one_declaration};
-use style::properties::animated_properties::AnimationValue;
+use style::properties::animated_properties::{AnimationValue, Interpolate};
 use style::restyle_hints::RestyleHint;
 use style::selector_parser::PseudoElementCascadeType;
 use style::sequential;
@@ -165,6 +167,39 @@ pub extern "C" fn Servo_TraverseSubtree(root: RawGeckoElementBorrowed,
                      behavior == structs::TraversalRootBehavior::UnstyledChildrenOnly);
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_AnimationValues_Interpolate(from: RawServoAnimationValueBorrowed,
+                                                    to: RawServoAnimationValueBorrowed,
+                                                    progress: f64)
+     -> RawServoAnimationValueStrong
+{
+    let from_value = AnimationValue::as_arc(&from);
+    let to_value = AnimationValue::as_arc(&to);
+    if let Ok(value) = from_value.interpolate(to_value, progress) {
+        Arc::new(value).into_strong()
+    } else {
+        RawServoAnimationValueStrong::null()
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_AnimationValues_Uncompute(value: RawServoAnimationValueBorrowedListBorrowed)
+     -> RawServoDeclarationBlockStrong
+{
+    let uncomputed_values = value.into_iter()
+                                 .map(|v| {
+                                     let raw_anim = unsafe { v.as_ref().unwrap() };
+                                     let anim = AnimationValue::as_arc(&raw_anim);
+                                     (anim.uncompute(), Importance::Normal)
+                                 })
+                                 .collect();
+
+    Arc::new(RwLock::new(PropertyDeclarationBlock {
+        declarations: uncomputed_values,
+        important_count: 0,
+    })).into_strong()
+}
+
 /// Takes a ServoAnimationValues and populates it with the animation values corresponding
 /// to a given property declaration block
 #[no_mangle]