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perf: cache portal split-divider regions off the hover/keyboard hot path (#18, upstream #6587) #30

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arzafran merged 2 commits into from
Jun 25, 2026
Merged

perf: cache portal split-divider regions off the hover/keyboard hot path (#18, upstream #6587) #30

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fe7ad93
fix: portal-hittest-cache (issue #6587) [salvaged from ultracode work…
arzafran Jun 25, 2026
c6662b4
fix: invalidate divider-region cache on split structure changes (#658…
arzafran Jun 25, 2026
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145 changes: 78 additions & 67 deletions Sources/BrowserWindowPortal.swift
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -276,6 +276,9 @@ final class WindowBrowserHostView: NSView {
private struct DividerRegion {
let rectInWindow: NSRect
let isVertical: Bool
/// True when the split view that owns this divider is a descendant of the
/// portal host view (i.e. an inspector/internal split, not an app-layout split).
let isInHostedContent: Bool
}

private struct DividerHit {
Expand Down Expand Up @@ -325,6 +328,9 @@ final class WindowBrowserHostView: NSView {
private var activeDividerCursorKind: DividerCursorKind?
private var hostedInspectorDividerDrag: HostedInspectorDividerDragState?
private var lastHostedInspectorLayoutBoundsSize: NSSize?
// PERF: Cache split-divider regions to avoid recursive view-tree walk on every
// pointer event. Invalidated on any geometry change.
private var cachedDividerRegions: [DividerRegion]?

deinit {
if let trackingArea {
Expand Down Expand Up @@ -376,6 +382,7 @@ final class WindowBrowserHostView: NSView {

override func viewDidMoveToWindow() {
super.viewDidMoveToWindow()
cachedDividerRegions = nil
if window == nil {
clearActiveDividerCursor(restoreArrow: false)
}
Expand All @@ -384,11 +391,13 @@ final class WindowBrowserHostView: NSView {

override func setFrameSize(_ newSize: NSSize) {
super.setFrameSize(newSize)
cachedDividerRegions = nil
window?.invalidateCursorRects(for: self)
}

override func setFrameOrigin(_ newOrigin: NSPoint) {
super.setFrameOrigin(newOrigin)
cachedDividerRegions = nil
window?.invalidateCursorRects(for: self)
}

Expand Down Expand Up @@ -419,9 +428,14 @@ final class WindowBrowserHostView: NSView {

override func resetCursorRects() {
super.resetCursorRects()
guard let rootView = dividerSearchRootView() else { return }
var regions: [DividerRegion] = []
Self.collectSplitDividerRegions(in: rootView, into: &regions)
// A split add/remove can change divider geometry without changing the host
// frame, so frame-hook invalidation alone is insufficient (#6587 review).
// Drop the cache here so the warm below reflects current structure;
// resetCursorRects is driven by invalidateCursorRects, not per pointer event.
cachedDividerRegions = nil
guard window != nil else { return }
// Warms the cache. Subsequent pointer events avoid the recursive walk.
let regions = dividerRegions()
let expansion: CGFloat = 4
for region in regions {
var rectInHost = convert(region.rectInWindow, from: nil)
Expand Down Expand Up @@ -468,6 +482,27 @@ final class WindowBrowserHostView: NSView {
}

override func hitTest(_ point: NSPoint) -> NSView? {
// PERF: hitTest is called on EVERY event including keyboard. Keep non-pointer
// path minimal. Mirror the isPointerEvent guard from WindowTerminalHostView.
let currentEvent = NSApp.currentEvent
let isPointerEvent: Bool
switch currentEvent?.type {
case .mouseMoved, .mouseEntered, .mouseExited,
.leftMouseDown, .leftMouseUp, .leftMouseDragged,
.rightMouseDown, .rightMouseUp, .rightMouseDragged,
.otherMouseDown, .otherMouseUp, .otherMouseDragged,
.scrollWheel, .cursorUpdate:
isPointerEvent = true
default:
isPointerEvent = false
}

if !isPointerEvent {
// Non-pointer event: skip divider/drag routing, just do standard hit testing.
let hitView = super.hitTest(point)
return hitView === self ? nil : hitView
}

let dividerHit = splitDividerHit(at: point)
let hostedInspectorHit = dividerHit == nil ? hostedInspectorDividerHit(at: point) : nil
updateDividerCursor(at: point, dividerHit: dividerHit, hostedInspectorHit: hostedInspectorHit)
Expand Down Expand Up @@ -825,11 +860,36 @@ final class WindowBrowserHostView: NSView {
}
}

// PERF: Returns the cached divider regions (including isInHostedContent), computing
// and caching on first call. The cache is invalidated by setFrameSize / setFrameOrigin /
// viewDidMoveToWindow. Do NOT call from non-pointer-event paths.
private func dividerRegions() -> [DividerRegion] {
if let cached = cachedDividerRegions { return cached }
guard let rootView = dividerSearchRootView() else {
cachedDividerRegions = []
return []
}
var regions: [DividerRegion] = []
Self.collectSplitDividerRegions(in: rootView, hostView: self, into: &regions)
cachedDividerRegions = regions
return regions
}

private func splitDividerHit(at point: NSPoint) -> DividerHit? {
guard window != nil else { return nil }
let windowPoint = convert(point, to: nil)
guard let rootView = dividerSearchRootView() else { return nil }
return Self.dividerHit(at: windowPoint, in: rootView, hostView: self)
let expansion: CGFloat = 5
for region in dividerRegions() {
// Mirror the original dividerHit expansion: expand in all directions.
let expanded = region.rectInWindow.insetBy(dx: -expansion, dy: -expansion)
if expanded.contains(windowPoint) {
return DividerHit(
kind: region.isVertical ? .vertical : .horizontal,
isInHostedContent: region.isInHostedContent
)
}
}
return nil
}

private func dividerSearchRootView() -> NSView? {
Expand Down Expand Up @@ -1084,65 +1144,6 @@ final class WindowBrowserHostView: NSView {
#endif
return (pageFrame, inspectorFrame)
}
private static func dividerHit(
at windowPoint: NSPoint,
in view: NSView,
hostView: WindowBrowserHostView
) -> DividerHit? {
guard !view.isHidden else { return nil }

if let splitView = view as? NSSplitView {
let pointInSplit = splitView.convert(windowPoint, from: nil)
if splitView.bounds.contains(pointInSplit) {
let expansion: CGFloat = 5
let dividerCount = max(0, splitView.arrangedSubviews.count - 1)
for dividerIndex in 0..<dividerCount {
let first = splitView.arrangedSubviews[dividerIndex].frame
let second = splitView.arrangedSubviews[dividerIndex + 1].frame
let thickness = splitView.dividerThickness
let dividerRect: NSRect
if splitView.isVertical {
// Keep divider hit-testing active even when one side is nearly collapsed,
// so users can drag the divider back out from the border.
// But ignore transient states where both panes are effectively 0-width.
guard first.width > 1 || second.width > 1 else { continue }
let x = max(0, first.maxX)
dividerRect = NSRect(
x: x,
y: 0,
width: thickness,
height: splitView.bounds.height
)
} else {
// Same behavior for horizontal splits with a near-zero-height pane.
guard first.height > 1 || second.height > 1 else { continue }
let y = max(0, first.maxY)
dividerRect = NSRect(
x: 0,
y: y,
width: splitView.bounds.width,
height: thickness
)
}
let expanded = dividerRect.insetBy(dx: -expansion, dy: -expansion)
if expanded.contains(pointInSplit) {
return DividerHit(
kind: splitView.isVertical ? .vertical : .horizontal,
isInHostedContent: splitView.isDescendant(of: hostView)
)
}
}
}
}

for subview in view.subviews.reversed() {
if let hit = dividerHit(at: windowPoint, in: subview, hostView: hostView) {
return hit
}
}

return nil
}

private static func verticalOverlap(between lhs: NSRect, and rhs: NSRect) -> CGFloat {
max(0, min(lhs.maxY, rhs.maxY) - max(lhs.minY, rhs.minY))
Expand Down Expand Up @@ -1187,7 +1188,11 @@ final class WindowBrowserHostView: NSView {
view.frame.height > 1
}

private static func collectSplitDividerRegions(in view: NSView, into result: inout [DividerRegion]) {
private static func collectSplitDividerRegions(
in view: NSView,
hostView: WindowBrowserHostView,
into result: inout [DividerRegion]
) {
guard !view.isHidden else { return }

if let splitView = view as? NSSplitView {
Expand All @@ -1211,14 +1216,15 @@ final class WindowBrowserHostView: NSView {
result.append(
DividerRegion(
rectInWindow: dividerRectInWindow,
isVertical: splitView.isVertical
isVertical: splitView.isVertical,
isInHostedContent: splitView.isDescendant(of: hostView)
)
)
}
}

for subview in view.subviews {
collectSplitDividerRegions(in: subview, into: &result)
collectSplitDividerRegions(in: subview, hostView: hostView, into: &result)
}
}

Expand Down Expand Up @@ -2324,6 +2330,11 @@ final class WindowBrowserPortal: NSObject {
reason: "externalGeometry"
)
}
// Split add/remove fires this (via NSSplitView.didResizeSubviewsNotification)
// without changing the host frame, so force a cursor-rect rebuild → the host
// drops its stale divider-region cache (see resetCursorRects) and the new
// divider is grabbable (#6587 review).
hostView.window?.invalidateCursorRects(for: hostView)
}

@discardableResult
Expand Down
53 changes: 47 additions & 6 deletions Sources/TerminalWindowPortal.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,9 @@ final class WindowTerminalHostView: NSView {
private var sidebarDividerMissCount = 0
private var trackingArea: NSTrackingArea?
private var activeDividerCursorKind: DividerCursorKind?
// PERF: Cache split-divider regions to avoid recursive view-tree walk on every
// pointer event. Invalidated on any geometry change.
private var cachedDividerRegions: [DividerRegion]?
#if DEBUG
private var lastDragRouteSignature: String?
#endif
Expand All @@ -63,6 +66,7 @@ final class WindowTerminalHostView: NSView {

override func viewDidMoveToWindow() {
super.viewDidMoveToWindow()
cachedDividerRegions = nil
if window == nil {
clearActiveDividerCursor(restoreArrow: false)
}
Expand All @@ -71,19 +75,28 @@ final class WindowTerminalHostView: NSView {

override func setFrameSize(_ newSize: NSSize) {
super.setFrameSize(newSize)
cachedDividerRegions = nil
window?.invalidateCursorRects(for: self)
}

override func setFrameOrigin(_ newOrigin: NSPoint) {
super.setFrameOrigin(newOrigin)
cachedDividerRegions = nil
window?.invalidateCursorRects(for: self)
}

override func resetCursorRects() {
super.resetCursorRects()
guard let window, let rootView = window.contentView else { return }
var regions: [DividerRegion] = []
Self.collectSplitDividerRegions(in: rootView, into: &regions)
// A split add/remove can change divider geometry without changing the host
// frame, so the frame-hook invalidation alone is insufficient (#6587 review).
// Drop the cache here so the warm below always reflects current structure;
// resetCursorRects is driven by invalidateCursorRects, not per pointer event,
// so this keeps the cache fresh per cursor-rect cycle without re-walking the
// tree on every hover.
cachedDividerRegions = nil
guard window != nil else { return }
// Warms the cache. Subsequent pointer events avoid the recursive walk.
let regions = dividerRegions()
let expansion: CGFloat = 4
for region in regions {
var rectInHost = convert(region.rectInWindow, from: nil)
Expand Down Expand Up @@ -275,11 +288,33 @@ final class WindowTerminalHostView: NSView {
}
}

// PERF: Returns the cached divider regions, computing and caching on first call.
// The cache is invalidated by setFrameSize / setFrameOrigin / viewDidMoveToWindow.
// Do NOT call from non-pointer-event paths.
private func dividerRegions() -> [DividerRegion] {
if let cached = cachedDividerRegions { return cached }
guard let rootView = window?.contentView else {
cachedDividerRegions = []
return []
}
var regions: [DividerRegion] = []
Self.collectSplitDividerRegions(in: rootView, into: &regions)
cachedDividerRegions = regions
return regions
}

private func splitDividerCursorKind(at point: NSPoint) -> DividerCursorKind? {
guard let window else { return nil }
guard window != nil else { return nil }
let windowPoint = convert(point, to: nil)
guard let rootView = window.contentView else { return nil }
return Self.dividerCursorKind(at: windowPoint, in: rootView)
let expansion: CGFloat = 5
for region in dividerRegions() {
// Mirror the original dividerCursorKind expansion: expand in all directions.
let expanded = region.rectInWindow.insetBy(dx: -expansion, dy: -expansion)
if expanded.contains(windowPoint) {
return region.isVertical ? .vertical : .horizontal
}
}
return nil
}

static func hasSplitDivider(atScreenPoint screenPoint: NSPoint, in window: NSWindow) -> Bool {
Expand Down Expand Up @@ -774,6 +809,12 @@ final class WindowTerminalPortal: NSObject {
synchronizeLayoutHierarchy()
synchronizeAllHostedViews(excluding: nil)
reconcileVisibleHostedViewsAfterGeometrySync(reason: "portal.externalGeometrySync")
// This fires on NSSplitView.didResizeSubviewsNotification (split add/remove),
// which can change divider geometry without changing the host frame — so the
// host's frame hooks never run. Force a cursor-rect rebuild so the host drops
// its stale divider-region cache (see resetCursorRects) and the new divider is
// grabbable (#6587 review).
hostView.window?.invalidateCursorRects(for: hostView)
}

private func ensureDividerOverlayOnTop() {
Expand Down
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