Bridge interrupted phased retargets

src/state.rs

@@ -7,7 +7,8 @@ use {
             RetainedToplevel,
             expand_damage_rect,
             multiphase::{
-                MultiphaseRequest, MultiphaseWindow, MultiphaseWindowHierarchy,
+                MultiphasePhase, MultiphasePlan, MultiphasePlanFailure, MultiphaseRequest,
+                MultiphaseWindow, MultiphaseWindowHierarchy,
                 partition_motion_groups, plan_no_overlap_with_diagnostics, validate_phase_paths,
             },
             spawn_in_start_rect,
@@ -205,6 +206,56 @@ fn layout_animation_group_uses_plain(
         .any(|&idx| candidates[idx].style == AnimationStyle::Plain)
 }
 
+fn bridged_retarget_plan(
+    request: &MultiphaseRequest,
+    candidates: &[LayoutAnimationCandidate],
+    group: &[usize],
+    bridge_paths: &[Vec<(Rect, Rect)>],
+    bridge_phase_count: usize,
+    follow_phases: &[MultiphasePhase],
+) -> Result<MultiphasePlan, MultiphasePlanFailure> {
+    let mut paths = vec![];
+    for (group_pos, &idx) in group.iter().enumerate() {
+        let candidate = &candidates[idx];
+        let window = request.windows[group_pos];
+        let Some(bridge_path) = bridge_paths.get(group_pos) else {
+            return Err(MultiphasePlanFailure::NoPattern);
+        };
+        let mut path = bridge_path.clone();
+        let mut current = path
+            .last()
+            .map(|(_, to)| *to)
+            .unwrap_or(window.from);
+        while path.len() < bridge_phase_count {
+            path.push((current, current));
+        }
+        if current != candidate.old {
+            return Err(MultiphasePlanFailure::NoPattern);
+        }
+        for phase in follow_phases {
+            match phase
+                .steps
+                .iter()
+                .find(|step| step.node_id == candidate.node_id)
+            {
+                Some(step) => {
+                    if step.from != current {
+                        return Err(MultiphasePlanFailure::NoPattern);
+                    }
+                    path.push((step.from, step.to));
+                    current = step.to;
+                }
+                None => path.push((current, current)),
+            }
+        }
+        if current != window.to {
+            return Err(MultiphasePlanFailure::NoPattern);
+        }
+        paths.push(path);
+    }
+    validate_phase_paths(request, &paths)
+}
+
 pub struct State {
     pub pid: c::pid_t,
     pub kb_ctx: KbvmContext,
@@ -1721,6 +1772,9 @@ impl State {
         if self.start_existing_phased_retarget(candidates, windows, group, &request, now_nsec) {
             return true;
         }
+        if self.start_bridged_phased_retarget(candidates, windows, group, &request, now_nsec) {
+            return true;
+        }
         let plan = match plan_no_overlap_with_diagnostics(&request) {
             Ok(plan) => plan,
             Err(diagnostic) => {
@@ -1770,6 +1824,97 @@ impl State {
         self.start_multiphase_plan(candidates, windows, group, &plan.phases, now_nsec)
     }
 
+    fn start_bridged_phased_retarget(
+        self: &Rc<Self>,
+        candidates: &[LayoutAnimationCandidate],
+        windows: &[MultiphaseWindow],
+        group: &[usize],
+        request: &MultiphaseRequest,
+        now_nsec: u64,
+    ) -> bool {
+        let mut bridge_paths = vec![];
+        let mut bridge_phase_count = 0;
+        let mut has_bridge = false;
+        for &idx in group {
+            let candidate = &candidates[idx];
+            let window = windows[idx];
+            if window.from == candidate.old {
+                bridge_paths.push(vec![]);
+                continue;
+            }
+            let Some(path) =
+                self.animations
+                    .phased_route_to(candidate.node_id, candidate.old, now_nsec)
+            else {
+                return false;
+            };
+            if !path.is_empty() {
+                has_bridge = true;
+                bridge_phase_count = bridge_phase_count.max(path.len());
+            }
+            bridge_paths.push(path);
+        }
+        if !has_bridge {
+            return false;
+        }
+
+        let settled_windows: Vec<_> = group
+            .iter()
+            .map(|&idx| {
+                let candidate = &candidates[idx];
+                MultiphaseWindow::with_hierarchy(
+                    candidate.node_id,
+                    candidate.old,
+                    candidate.new,
+                    candidate.hierarchy,
+                )
+            })
+            .collect();
+        let Some(first) = settled_windows.first() else {
+            return false;
+        };
+        let mut bounds = first.from.union(first.to);
+        for window in &settled_windows[1..] {
+            bounds = bounds.union(window.from).union(window.to);
+        }
+        let settled_request = MultiphaseRequest {
+            bounds,
+            windows: settled_windows,
+            clearance: self.layout_animation_clearance(),
+        };
+        let follow_plan = match plan_no_overlap_with_diagnostics(&settled_request) {
+            Ok(plan) => plan,
+            Err(diagnostic) => {
+                log::debug!(
+                    "bridged phased retarget follow-up rejected for group {:?}: {:?}",
+                    group,
+                    diagnostic
+                );
+                return false;
+            }
+        };
+        let plan = match bridged_retarget_plan(
+            request,
+            candidates,
+            group,
+            &bridge_paths,
+            bridge_phase_count,
+            &follow_plan.phases,
+        ) {
+            Ok(plan) => plan,
+            Err(error) => {
+                log::debug!(
+                    "bridged phased retarget rejected for group {:?}: {:?}",
+                    group,
+                    error
+                );
+                return false;
+            }
+        };
+        log::debug!("bridging active phased animation for group {:?}", group);
+        self.start_multiphase_plan(candidates, windows, group, &plan.phases, now_nsec)
+    }
+
     fn start_multiphase_plan(
         self: &Rc<Self>,
         candidates: &[LayoutAnimationCandidate],
@@ -2512,10 +2657,24 @@ mod tests {
     }
 
     fn candidate(node_id: u32, style: AnimationStyle) -> LayoutAnimationCandidate {
+        candidate_rects(
+            node_id,
+            rect(0, 0, 100, 100),
+            rect(100, 0, 200, 100),
+            style,
+        )
+    }
+
+    fn candidate_rects(
+        node_id: u32,
+        old: Rect,
+        new: Rect,
+        style: AnimationStyle,
+    ) -> LayoutAnimationCandidate {
         LayoutAnimationCandidate {
             node_id: NodeId(node_id),
-            old: rect(0, 0, 100, 100),
+            old,
-            new: rect(100, 0, 200, 100),
+            new,
             curve: AnimationCurve::Linear,
             style,
             hierarchy: MultiphaseWindowHierarchy::default(),
@@ -2533,6 +2692,57 @@ mod tests {
         assert!(layout_animation_group_uses_plain(&candidates, &[0, 1]));
     }
 
+    #[test]
+    fn bridged_retarget_handles_second_rotation_interrupt() {
+        let a_left = rect(0, 0, 100, 100);
+        let c_mid = rect(100, 0, 200, 100);
+        let c_left = a_left;
+        let a_mid = c_mid;
+        let c_current = rect(150, 50, 250, 100);
+        let c_mid_lane = rect(100, 50, 200, 100);
+        let candidates = vec![
+            candidate_rects(1, a_left, a_mid, AnimationStyle::Multiphase),
+            candidate_rects(3, c_mid, c_left, AnimationStyle::Multiphase),
+        ];
+        let request = MultiphaseRequest {
+            bounds: rect(0, 0, 250, 100),
+            windows: vec![
+                MultiphaseWindow::new(NodeId(1), a_left, a_mid),
+                MultiphaseWindow::new(NodeId(3), c_current, c_left),
+            ],
+            clearance: 0,
+        };
+        let settled_request = MultiphaseRequest {
+            bounds: rect(0, 0, 200, 100),
+            windows: vec![
+                MultiphaseWindow::new(NodeId(1), a_left, a_mid),
+                MultiphaseWindow::new(NodeId(3), c_mid, c_left),
+            ],
+            clearance: 0,
+        };
+        let follow_plan = plan_no_overlap_with_diagnostics(&settled_request).unwrap();
+        let bridge_paths = vec![vec![], vec![(c_current, c_mid_lane), (c_mid_lane, c_mid)]];
+
+        let plan = bridged_retarget_plan(
+            &request,
+            &candidates,
+            &[0, 1],
+            &bridge_paths,
+            2,
+            &follow_plan.phases,
+        )
+        .unwrap();
+
+        assert!(plan
+            .phases
+            .iter()
+            .any(|phase| phase.steps.iter().any(|step| step.node_id == NodeId(1))));
+        assert!(plan
+            .phases
+            .iter()
+            .any(|phase| phase.steps.iter().any(|step| step.node_id == NodeId(3))));
+    }
+
     #[test]
     fn layout_animation_candidates_coalesce_duplicate_nodes() {
         let source = MultiphaseHierarchyPosition {