From cd2b26bc949d3a6f347d4dd2e2d27b502423ae73 Mon Sep 17 00:00:00 2001
From: Dariusz Komosinski <darek.komosinski@gmail.com>
Date: Fri, 1 May 2020 20:09:36 +0200
Subject: [PATCH] Add extra methods to LogicalExtensions and optimize a few
 methods as well.

---
 .../Platform/DefaultMenuInteractionHandler.cs |  2 +-
 .../ManagedFileChooser.xaml.cs                |  2 +-
 .../LogicalTree/LogicalExtensions.cs          | 93 ++++++++++++++++++-
 .../VisualTree/VisualExtensions.cs            | 14 ++-
 4 files changed, 105 insertions(+), 6 deletions(-)

diff --git a/src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs b/src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs
index 3715bc52a4..8ad622ba4a 100644
--- a/src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs
+++ b/src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs
@@ -392,7 +392,7 @@ namespace Avalonia.Controls.Platform
             {
                 var control = e.Source as ILogical;
 
-                if (!Menu.IsLogicalParentOf(control))
+                if (!Menu.IsLogicalAncestorOf(control))
                 {
                     Menu.Close();
                 }
diff --git a/src/Avalonia.Dialogs/ManagedFileChooser.xaml.cs b/src/Avalonia.Dialogs/ManagedFileChooser.xaml.cs
index b967b40c0d..616f260397 100644
--- a/src/Avalonia.Dialogs/ManagedFileChooser.xaml.cs
+++ b/src/Avalonia.Dialogs/ManagedFileChooser.xaml.cs
@@ -34,7 +34,7 @@ namespace Avalonia.Dialogs
                 return;
             }
 
-            var isQuickLink = _quickLinksRoot.IsLogicalParentOf(e.Source as Control);
+            var isQuickLink = _quickLinksRoot.IsLogicalAncestorOf(e.Source as Control);
             if (e.ClickCount == 2 || isQuickLink)
             {
                 if (model.ItemType == ManagedFileChooserItemType.File)
diff --git a/src/Avalonia.Styling/LogicalTree/LogicalExtensions.cs b/src/Avalonia.Styling/LogicalTree/LogicalExtensions.cs
index 1003375978..bd05796578 100644
--- a/src/Avalonia.Styling/LogicalTree/LogicalExtensions.cs
+++ b/src/Avalonia.Styling/LogicalTree/LogicalExtensions.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 
 namespace Avalonia.LogicalTree
 {
@@ -29,6 +28,35 @@ namespace Avalonia.LogicalTree
             }
         }
 
+        /// <summary>
+        /// Finds first ancestor of given type.
+        /// </summary>
+        /// <typeparam name="T">Ancestor type.</typeparam>
+        /// <param name="logical">The logical.</param>
+        /// <param name="includeSelf">If given logical should be included in search.</param>
+        /// <returns>First ancestor of given type.</returns>
+        public static T FindLogicalAncestorOfType<T>(this ILogical logical, bool includeSelf = false) where T : class
+        {
+            if (logical is null)
+            {
+                return null;
+            }
+
+            ILogical parent = includeSelf ? logical : logical.LogicalParent;
+
+            while (parent != null)
+            {
+                if (parent is T result)
+                {
+                    return result;
+                }
+
+                parent = parent.LogicalParent;
+            }
+
+            return null;
+        }
+
         public static IEnumerable<ILogical> GetLogicalChildren(this ILogical logical)
         {
             return logical.LogicalChildren;
@@ -57,6 +85,28 @@ namespace Avalonia.LogicalTree
             }
         }
 
+        /// <summary>
+        /// Finds first descendant of given type.
+        /// </summary>
+        /// <typeparam name="T">Descendant type.</typeparam>
+        /// <param name="logical">The logical.</param>
+        /// <param name="includeSelf">If given logical should be included in search.</param>
+        /// <returns>First descendant of given type.</returns>
+        public static T FindLogicalDescendantOfType<T>(this ILogical logical, bool includeSelf = false) where T : class
+        {
+            if (logical is null)
+            {
+                return null;
+            }
+
+            if (includeSelf && logical is T result)
+            {
+                return result;
+            }
+
+            return FindDescendantOfTypeCore<T>(logical);
+        }
+
         public static ILogical GetLogicalParent(this ILogical logical)
         {
             return logical.LogicalParent;
@@ -80,9 +130,46 @@ namespace Avalonia.LogicalTree
             }
         }
 
-        public static bool IsLogicalParentOf(this ILogical logical, ILogical target)
+        public static bool IsLogicalAncestorOf(this ILogical logical, ILogical target)
         {
-            return target.GetLogicalAncestors().Any(x => x == logical);
+            ILogical current = target?.LogicalParent;
+
+            while (current != null)
+            {
+                if (current == logical)
+                {
+                    return true;
+                }
+
+                current = current.LogicalParent;
+            }
+
+            return false;
+        }
+
+        private static T FindDescendantOfTypeCore<T>(ILogical logical) where T : class
+        {
+            var logicalChildren = logical.LogicalChildren;
+            var logicalChildrenCount = logicalChildren.Count;
+
+            for (var i = 0; i < logicalChildrenCount; i++)
+            {
+                ILogical child = logicalChildren[i];
+
+                if (child is T result)
+                {
+                    return result;
+                }
+
+                var childResult = FindDescendantOfTypeCore<T>(child);
+
+                if (!(childResult is null))
+                {
+                    return childResult;
+                }
+            }
+
+            return null;
         }
     }
 }
diff --git a/src/Avalonia.Visuals/VisualTree/VisualExtensions.cs b/src/Avalonia.Visuals/VisualTree/VisualExtensions.cs
index 4b3e757e7a..636aa6836e 100644
--- a/src/Avalonia.Visuals/VisualTree/VisualExtensions.cs
+++ b/src/Avalonia.Visuals/VisualTree/VisualExtensions.cs
@@ -377,7 +377,19 @@ namespace Avalonia.VisualTree
         /// </returns>
         public static bool IsVisualAncestorOf(this IVisual visual, IVisual target)
         {
-            return target.GetVisualAncestors().Any(x => x == visual);
+            IVisual current = target;
+
+            while (current != null)
+            {
+                if (current == visual)
+                {
+                    return true;
+                }
+
+                current = current.VisualParent;
+            }
+
+            return false;
         }
 
         public static IEnumerable<IVisual> SortByZIndex(this IEnumerable<IVisual> elements)