Skip Invalidation unless you're my immediate child

dotnet · Nov 4, 2024 · 0afbdca · 0afbdca
1 parent e8c96c5
commit 0afbdca
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Showing 4 changed files with 129 additions and 17 deletions.
diff --git a/src/Controls/src/Core/LegacyLayouts/Layout.cs b/src/Controls/src/Core/LegacyLayouts/Layout.cs
@@ -341,10 +341,12 @@ protected virtual void InvalidateLayout()
 		[Obsolete("Use ArrangeOverride")]
 		protected abstract void LayoutChildren(double x, double y, double width, double height);
 
-		internal override void OnChildMeasureInvalidatedInternal(VisualElement child, InvalidationTrigger trigger)
+		internal override void OnChildMeasureInvalidatedInternal(VisualElement child, InvalidationTrigger trigger, int depth)
 		{
+			CurrentInvalidationDepth = depth;
 			// TODO: once we remove old Xamarin public signatures we can invoke `OnChildMeasureInvalidated(VisualElement, InvalidationTrigger)` directly
 			OnChildMeasureInvalidated(child, new InvalidationEventArgs(trigger));
+			CurrentInvalidationDepth = 0;
 		}
 
 		/// <summary>
@@ -356,8 +358,10 @@ internal override void OnChildMeasureInvalidatedInternal(VisualElement child, In
 		/// <remarks>This method has a default implementation and application developers must call the base implementation.</remarks>
 		protected void OnChildMeasureInvalidated(object sender, EventArgs e)
 		{
+			var depth = CurrentInvalidationDepth;
+			CurrentInvalidationDepth = 0;
 			InvalidationTrigger trigger = (e as InvalidationEventArgs)?.Trigger ?? InvalidationTrigger.Undefined;
-			OnChildMeasureInvalidated((VisualElement)sender, trigger);
+			OnChildMeasureInvalidated((VisualElement)sender, trigger, depth);
 			OnChildMeasureInvalidated();
 		}
 
@@ -531,7 +535,7 @@ internal static void LayoutChildIntoBoundingRegion(View child, Rect region, Size
 			child.Layout(region);
 		}
 
-		internal virtual void OnChildMeasureInvalidated(VisualElement child, InvalidationTrigger trigger)
+		internal virtual void OnChildMeasureInvalidated(VisualElement child, InvalidationTrigger trigger, int depth)
 		{
 			IReadOnlyList<Element> children = LogicalChildrenInternal;
 			int count = children.Count;
@@ -557,13 +561,24 @@ internal virtual void OnChildMeasureInvalidated(VisualElement child, Invalidatio
 				}
 			}
 
-			if (trigger == InvalidationTrigger.RendererReady)
+			if (depth <= 1)
 			{
-				InvalidateMeasureInternal(InvalidationTrigger.RendererReady);
+
+				CurrentInvalidationDepth = depth;
+				if (trigger == InvalidationTrigger.RendererReady)
+				{
+					InvalidateMeasureInternal(InvalidationTrigger.RendererReady);
+				}
+				else
+				{
+					InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
+				}
+
+				CurrentInvalidationDepth = 0;
 			}
 			else
 			{
-				InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
+				FireMeasureChanged(trigger, depth);
 			}
 		}
 

diff --git a/src/Controls/src/Core/Page/Page.cs b/src/Controls/src/Core/Page/Page.cs
@@ -500,10 +500,13 @@ protected override void OnBindingContextChanged()
 				SetInheritedBindingContext(TitleView, BindingContext);
 		}
 
-		internal override void OnChildMeasureInvalidatedInternal(VisualElement child, InvalidationTrigger trigger)
+
+		internal override void OnChildMeasureInvalidatedInternal(VisualElement child, InvalidationTrigger trigger, int depth)
 		{
+			CurrentInvalidationDepth = depth;
 			// TODO: once we remove old Xamarin public signatures we can invoke `OnChildMeasureInvalidated(VisualElement, InvalidationTrigger)` directly
 			OnChildMeasureInvalidated(child, new InvalidationEventArgs(trigger));
+			CurrentInvalidationDepth = 0;
 		}
 
 		/// <summary>
@@ -514,7 +517,9 @@ internal override void OnChildMeasureInvalidatedInternal(VisualElement child, In
 		protected virtual void OnChildMeasureInvalidated(object sender, EventArgs e)
 		{
 			InvalidationTrigger trigger = (e as InvalidationEventArgs)?.Trigger ?? InvalidationTrigger.Undefined;
-			OnChildMeasureInvalidated((VisualElement)sender, trigger);
+			var depth = CurrentInvalidationDepth;
+			CurrentInvalidationDepth = 0;
+			OnChildMeasureInvalidated((VisualElement)sender, trigger, depth);
 		}
 
 		/// <summary>
@@ -593,7 +598,7 @@ protected void UpdateChildrenLayout()
 			}
 		}
 
-		internal virtual void OnChildMeasureInvalidated(VisualElement child, InvalidationTrigger trigger)
+		internal virtual void OnChildMeasureInvalidated(VisualElement child, InvalidationTrigger trigger, int depth)
 		{
 			var container = this as IPageContainer<Page>;
 			if (container != null)
@@ -613,7 +618,16 @@ internal virtual void OnChildMeasureInvalidated(VisualElement child, Invalidatio
 				}
 			}
 
-			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
+			if (depth <= 1)
+			{
+				CurrentInvalidationDepth = depth;
+				InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
+				CurrentInvalidationDepth = 0;
+			}
+			else
+			{
+				FireMeasureChanged(trigger, depth);
+			}
 		}
 
 		internal void OnAppearing(Action action)

diff --git a/src/Controls/src/Core/VisualElement/VisualElement.cs b/src/Controls/src/Core/VisualElement/VisualElement.cs
@@ -1370,6 +1370,11 @@ public void InvalidateMeasureNonVirtual(InvalidationTrigger trigger)
 		}
 
 		internal virtual void InvalidateMeasureInternal(InvalidationTrigger trigger)
+		{
+			InvalidateMeasureInternal(trigger, CurrentInvalidationDepth);
+		}
+
+		internal void InvalidateMeasureInternal(InvalidationTrigger trigger, int depth)
 		{
 			_measureCache.Clear();
 
@@ -1388,11 +1393,21 @@ internal virtual void InvalidateMeasureInternal(InvalidationTrigger trigger)
 					break;
 			}
 
+			FireMeasureChanged(trigger, depth);
+		}
+
+		private protected void FireMeasureChanged(InvalidationTrigger trigger, int depth)
+		{
 			MeasureInvalidated?.Invoke(this, new InvalidationEventArgs(trigger));
-			(Parent as VisualElement)?.OnChildMeasureInvalidatedInternal(this, trigger);
+			(Parent as VisualElement)?.OnChildMeasureInvalidatedInternal(this, trigger, ++depth);
 		}
+
+		// We don't want to change the execution path of Page or Layout when they are calling "InvalidationMeasure"
+		// If you look at page it calls OnChildMeasureInvalidated from OnChildMeasureInvalidatedInternal
+		// Because OnChildMeasureInvalidated is public API and the user might override it, we need to keep it as is
+		private protected int CurrentInvalidationDepth {get; set; }
 
-		internal virtual void OnChildMeasureInvalidatedInternal(VisualElement child, InvalidationTrigger trigger)
+		internal virtual void OnChildMeasureInvalidatedInternal(VisualElement child, InvalidationTrigger trigger, int depth)
 		{
 			switch (trigger)
 			{
@@ -1404,17 +1419,14 @@ internal virtual void OnChildMeasureInvalidatedInternal(VisualElement child, Inv
 				case InvalidationTrigger.RendererReady:
 				// Undefined happens in many cases, including when `IsVisible` changes
 				case InvalidationTrigger.Undefined:
-					MeasureInvalidated?.Invoke(this, new InvalidationEventArgs(trigger));
-					(Parent as VisualElement)?.OnChildMeasureInvalidatedInternal(this, trigger);
+					FireMeasureChanged(trigger, depth);
 					return;
 				default:
 					// When visibility changes `InvalidationTrigger.Undefined` is used,
 					// so here we're sure that visibility didn't change
 					if (child.IsVisible)
 					{
-						// We need to invalidate measures only if child is actually visible
-						MeasureInvalidated?.Invoke(this, new InvalidationEventArgs(InvalidationTrigger.MeasureChanged));
-						(Parent as VisualElement)?.OnChildMeasureInvalidatedInternal(this, InvalidationTrigger.MeasureChanged);
+						FireMeasureChanged(InvalidationTrigger.MeasureChanged, depth);
 					}
 					return;
 			}

diff --git a/src/Controls/tests/Core.UnitTests/PageTests.cs b/src/Controls/tests/Core.UnitTests/PageTests.cs
@@ -549,5 +549,76 @@ public void LogicalChildrenDontAddToPagesInternalChildren()
 			Assert.Contains(customControl, page.LogicalChildrenInternal);
 			Assert.Contains(customControl, ((IVisualTreeElement)page).GetVisualChildren());
 		}
+
+		[Fact]
+		public void MeasureInvalidatedPropagatesUpTree()
+		{
+			var label = new Label(){
+				IsPlatformEnabled = true
+			};
+
+			var scrollView = new ScrollViewCheck()
+			{
+				Content = new VerticalStackLayout()
+				{
+					Children = { new ContentView { Content = label, IsPlatformEnabled = true } },
+					IsPlatformEnabled = true
+				},
+				IsPlatformEnabled = true
+			};
+
+			var page = new InvalidatePageCheck()
+			{
+				Content = scrollView
+			};
+
+			var window = new TestWindow(page);
+
+			int fired = 0;
+			page.MeasureInvalidated += (sender, args) =>
+			{
+				fired++;
+			};
+
+			page.Fired = 0;
+			scrollView.Fired = 0;
+			label.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
+			Assert.Equal(1, fired);
+			Assert.Equal(0, page.Fired);
+			Assert.Equal(0, scrollView.Fired);
+			page.Content.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
+			Assert.Equal(1, page.Fired);
+		}
+
+		class ScrollViewCheck : ScrollView
+		{
+			public int Fired { get; set; }
+
+			public ScrollViewCheck()
+			{
+
+			}
+
+			internal override void InvalidateMeasureInternal(InvalidationTrigger trigger)
+			{
+				base.InvalidateMeasureInternal(trigger);
+				Fired++;
+			}
+		}
+
+		class InvalidatePageCheck : ContentPage
+		{
+			public int Fired { get; set; }
+
+			public InvalidatePageCheck()
+			{
+
+			}
+
+			internal override void InvalidateMeasureInternal(InvalidationTrigger trigger)
+			{
+				Fired++;
+			}
+		}
 	}
 }