Add support for transitionrun events

These events are triggered as soon as a transition is added to the list
of running transitions. This will allow better test coverage while
reworking the transitions and animations processing model.

1 files changed, 78 insertions, 55 deletions

diff --git a/components/layout/animation.rs b/components/layout/animation.rs
index 185b6d9c9d1..57db0abda42 100644
--- a/components/layout/animation.rs
+++ b/components/layout/animation.rs
@@ -15,54 +15,62 @@ use script_traits::UntrustedNodeAddress;
 use script_traits::{
     AnimationState, ConstellationControlMsg, LayoutMsg as ConstellationMsg, TransitionEventType,
 };
-use style::animation::{update_style_for_animation, Animation, ElementAnimationState};
+use style::animation::{
+    update_style_for_animation, Animation, ElementAnimationState, PropertyAnimation,
+};
 use style::dom::TElement;
 use style::font_metrics::ServoMetricsProvider;
 use style::selector_parser::RestyleDamage;
 use style::timer::Timer;
 
+/// Collect newly transitioning nodes, which is used by the script process during
+/// forced, synchronous reflows to root DOM nodes for the duration of their transitions.
+pub fn collect_newly_transitioning_nodes(
+    animation_states: &FxHashMap<OpaqueNode, ElementAnimationState>,
+    mut out: Option<&mut Vec<UntrustedNodeAddress>>,
+) {
+    // This extends the output vector with an iterator that contains a copy of the node
+    // address for every new animation. This is a bit goofy, but the script thread
+    // currently stores a rooted node for every property that is transitioning.
+    if let Some(ref mut out) = out {
+        out.extend(animation_states.iter().flat_map(|(node, state)| {
+            let num_transitions = state
+                .new_animations
+                .iter()
+                .filter(|animation| animation.is_transition())
+                .count();
+            std::iter::repeat(node.to_untrusted_node_address()).take(num_transitions)
+        }));
+    }
+}
+
 /// Processes any new animations that were discovered after style recalculation. Also
 /// finish any animations that have completed, inserting them into `finished_animations`.
-pub fn update_animation_states<E>(
+pub fn update_animation_states(
     constellation_chan: &IpcSender<ConstellationMsg>,
     script_chan: &IpcSender<ConstellationControlMsg>,
     animation_states: &mut FxHashMap<OpaqueNode, ElementAnimationState>,
     invalid_nodes: FxHashSet<OpaqueNode>,
-    mut newly_transitioning_nodes: Option<&mut Vec<UntrustedNodeAddress>>,
     pipeline_id: PipelineId,
     timer: &Timer,
-) where
-    E: TElement,
-{
+) {
     let had_running_animations = animation_states
         .values()
         .any(|state| !state.running_animations.is_empty());
 
+    // Cancel all animations on any invalid nodes. These entries will later
+    // be removed from the list of states, because their states will become
+    // empty.
     for node in &invalid_nodes {
         if let Some(mut state) = animation_states.remove(node) {
             state.cancel_all_animations();
-            send_events_for_cancelled_animations(script_chan, &mut state, pipeline_id);
         }
     }
 
     let now = timer.seconds();
     let mut have_running_animations = false;
     for (node, animation_state) in animation_states.iter_mut() {
-        // TODO(mrobinson): This should really be triggering transitionrun messages
-        // on the script thread.
-        if let Some(ref mut newly_transitioning_nodes) = newly_transitioning_nodes {
-            let number_of_new_transitions = animation_state
-                .new_animations
-                .iter()
-                .filter(|animation| animation.is_transition())
-                .count();
-            for _ in 0..number_of_new_transitions {
-                newly_transitioning_nodes.push(node.to_untrusted_node_address());
-            }
-        }
-
-        update_animation_state::<E>(script_chan, animation_state, pipeline_id, now);
-
+        update_animation_state(script_chan, animation_state, pipeline_id, now, *node);
         have_running_animations =
             have_running_animations || !animation_state.running_animations.is_empty();
     }
@@ -85,16 +93,37 @@ pub fn update_animation_states<E>(
         .unwrap();
 }
 
-pub fn update_animation_state<E>(
-    script_chan: &IpcSender<ConstellationControlMsg>,
+pub fn update_animation_state(
+    script_channel: &IpcSender<ConstellationControlMsg>,
     animation_state: &mut ElementAnimationState,
     pipeline_id: PipelineId,
     now: f64,
-) where
-    E: TElement,
-{
-    send_events_for_cancelled_animations(script_chan, animation_state, pipeline_id);
+    node: OpaqueNode,
+) {
+    let send_transition_event = |property_animation: &PropertyAnimation, event_type| {
+        script_channel
+            .send(ConstellationControlMsg::TransitionEvent {
+                pipeline_id,
+                event_type,
+                node: node.to_untrusted_node_address(),
+                property_name: property_animation.property_name().into(),
+                elapsed_time: property_animation.duration,
+            })
+            .unwrap()
+    };
 
+    handle_cancelled_animations(animation_state, send_transition_event);
+    handle_running_animations(animation_state, now, send_transition_event);
+    handle_new_animations(animation_state, send_transition_event);
+}
+
+/// Walk through the list of running animations and remove all of the ones that
+/// have ended.
+pub fn handle_running_animations(
+    animation_state: &mut ElementAnimationState,
+    now: f64,
+    mut send_transition_event: impl FnMut(&PropertyAnimation, TransitionEventType),
+) {
     let mut running_animations =
         std::mem::replace(&mut animation_state.running_animations, Vec::new());
     for mut running_animation in running_animations.drain(..) {
@@ -115,46 +144,25 @@ pub fn update_animation_state<E>(
             animation_state.running_animations.push(running_animation);
         } else {
             debug!("Finishing transition: {:?}", running_animation);
-            if let Animation::Transition(node, _, ref property_animation) = running_animation {
-                script_chan
-                    .send(ConstellationControlMsg::TransitionEvent {
-                        pipeline_id,
-                        event_type: TransitionEventType::TransitionEnd,
-                        node: node.to_untrusted_node_address(),
-                        property_name: property_animation.property_name().into(),
-                        elapsed_time: property_animation.duration,
-                    })
-                    .unwrap();
+            if let Animation::Transition(_, _, ref property_animation) = running_animation {
+                send_transition_event(property_animation, TransitionEventType::TransitionEnd);
             }
             animation_state.finished_animations.push(running_animation);
         }
     }
-
-    animation_state
-        .running_animations
-        .append(&mut animation_state.new_animations);
 }
 
 /// Send events for cancelled animations. Currently this only handles cancelled
 /// transitions, but eventually this should handle cancelled CSS animations as
 /// well.
-pub fn send_events_for_cancelled_animations(
-    script_channel: &IpcSender<ConstellationControlMsg>,
+pub fn handle_cancelled_animations(
     animation_state: &mut ElementAnimationState,
-    pipeline_id: PipelineId,
+    mut send_transition_event: impl FnMut(&PropertyAnimation, TransitionEventType),
 ) {
     for animation in animation_state.cancelled_animations.drain(..) {
         match animation {
-            Animation::Transition(node, _, ref property_animation) => {
-                script_channel
-                    .send(ConstellationControlMsg::TransitionEvent {
-                        pipeline_id,
-                        event_type: TransitionEventType::TransitionCancel,
-                        node: node.to_untrusted_node_address(),
-                        property_name: property_animation.property_name().into(),
-                        elapsed_time: property_animation.duration,
-                    })
-                    .unwrap();
+            Animation::Transition(_, _, ref property_animation) => {
+                send_transition_event(property_animation, TransitionEventType::TransitionCancel)
             },
             Animation::Keyframes(..) => {
                 warn!("Got unexpected animation in finished transitions list.")
@@ -163,6 +171,21 @@ pub fn send_events_for_cancelled_animations(
     }
 }
 
+pub fn handle_new_animations(
+    animation_state: &mut ElementAnimationState,
+    mut send_transition_event: impl FnMut(&PropertyAnimation, TransitionEventType),
+) {
+    for animation in animation_state.new_animations.drain(..) {
+        match animation {
+            Animation::Transition(_, _, ref property_animation) => {
+                send_transition_event(property_animation, TransitionEventType::TransitionRun)
+            },
+            Animation::Keyframes(..) => {},
+        }
+        animation_state.running_animations.push(animation);
+    }
+}
+
 /// Recalculates style for a set of animations. This does *not* run with the DOM
 /// lock held. Returns a set of nodes associated with animations that are no longer
 /// valid.