From 276a33963143e02174b85d3165a0e66ff7951b45 Mon Sep 17 00:00:00 2001
From: h3xds1nz <gamingshard@protonmail.com>
Date: Sat, 29 Mar 2025 20:39:23 +0100
Subject: [PATCH 1/2] Avoid boxing booleans allocations in UncommonField<bool>
---
.../System/Windows/UncommonField.cs | 25 ++++++++-----------
1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/UncommonField.cs b/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/UncommonField.cs
index 89757905d9c..c149054da8c 100644
--- a/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/UncommonField.cs
+++ b/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/UncommonField.cs
@@ -1,4 +1,4 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
@@ -44,24 +44,21 @@ public void SetValue(DependencyObject instance, T value)
EntryIndex entryIndex = instance.LookupEntry(_globalIndex);
- // Set the value if it's not the default, otherwise remove the value.
- if (!object.ReferenceEquals(value, _defaultValue))
+ // Special case boolean operations to avoid boxing with (mostly) UIA code paths
+ if (typeof(T) == typeof(bool))
{
- object valueObject;
-
- if (typeof(T) == typeof(bool))
- {
- // Use shared boxed instances rather than creating new objects for each SetValue call.
- valueObject = BooleanBoxes.Box(Unsafe.As<T, bool>(ref value));
- }
- else
- {
- valueObject = value;
- }
+ // Use shared boxed instances rather than creating new objects for each SetValue call.
+ object valueObject = BooleanBoxes.Box(Unsafe.BitCast<T, bool>(value));
instance.SetEffectiveValue(entryIndex, dp: null, _globalIndex, metadata: null, valueObject, BaseValueSourceInternal.Local);
_hasBeenSet = true;
}
+ // Set the value if it's not the default, otherwise remove the value.
+ else if (!ReferenceEquals(value, _defaultValue))
+ {
+ instance.SetEffectiveValue(entryIndex, dp: null, _globalIndex, metadata: null, value, BaseValueSourceInternal.Local);
+ _hasBeenSet = true;
+ }
else
{
instance.UnsetEffectiveValue(entryIndex, dp: null, metadata: null);
From eb11ad5af192b9356259084b1d592387f0a14b53 Mon Sep 17 00:00:00 2001
From: h3xds1nz <gamingshard@protonmail.com>
Date: Sun, 30 Mar 2025 21:05:57 +0200
Subject: [PATCH 2/2] Clean up the class, add some comments
---
.../System/Windows/UncommonField.cs | 57 +++++++++----------
1 file changed, 27 insertions(+), 30 deletions(-)
diff --git a/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/UncommonField.cs b/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/UncommonField.cs
index c149054da8c..d858a0316f6 100644
--- a/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/UncommonField.cs
+++ b/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/Windows/UncommonField.cs
@@ -10,31 +10,44 @@ namespace System.Windows
internal class UncommonField<T>
{
/// <summary>
- /// Create a new UncommonField.
+ /// Zero-based, globally unique index, retrieved via <see cref="DependencyProperty.GetUniqueGlobalIndex"/>.
/// </summary>
- public UncommonField() : this(default(T))
+ internal int GlobalIndex { get; }
+
+ /// <summary>
+ /// Determines the default value for this field, assigned during initial construction.
+ /// </summary>
+ private readonly T _defaultValue;
+ /// <summary>
+ /// An optimization detail representing whether a non-default value is currently stored.
+ /// </summary>
+ private bool _hasBeenSet;
+
+ /// <summary>
+ /// Create a new UncommonField. Stores <see langword="default"/>(<typeparamref name="T"/>) value as default.
+ /// </summary>
+ public UncommonField() : this(default)
{
}
/// <summary>
- /// Create a new UncommonField.
+ /// Create a new UncommonField.
/// </summary>
/// <param name="defaultValue">The default value of the field.</param>
public UncommonField(T defaultValue)
{
_defaultValue = defaultValue;
- _hasBeenSet = false;
lock (DependencyProperty.Synchronized)
{
- _globalIndex = DependencyProperty.GetUniqueGlobalIndex(null, null);
+ GlobalIndex = DependencyProperty.GetUniqueGlobalIndex(null, null);
DependencyProperty.RegisteredPropertyList.Add();
}
}
/// <summary>
- /// Write the given value onto a DependencyObject instance.
+ /// Write the given value onto a DependencyObject instance.
/// </summary>
/// <param name="instance">The DependencyObject on which to set the value.</param>
/// <param name="value">The value to set.</param>
@@ -42,7 +55,7 @@ public void SetValue(DependencyObject instance, T value)
{
ArgumentNullException.ThrowIfNull(instance);
- EntryIndex entryIndex = instance.LookupEntry(_globalIndex);
+ EntryIndex entryIndex = instance.LookupEntry(GlobalIndex);
// Special case boolean operations to avoid boxing with (mostly) UIA code paths
if (typeof(T) == typeof(bool))
@@ -50,13 +63,13 @@ public void SetValue(DependencyObject instance, T value)
// Use shared boxed instances rather than creating new objects for each SetValue call.
object valueObject = BooleanBoxes.Box(Unsafe.BitCast<T, bool>(value));
- instance.SetEffectiveValue(entryIndex, dp: null, _globalIndex, metadata: null, valueObject, BaseValueSourceInternal.Local);
+ instance.SetEffectiveValue(entryIndex, dp: null, GlobalIndex, metadata: null, valueObject, BaseValueSourceInternal.Local);
_hasBeenSet = true;
}
// Set the value if it's not the default, otherwise remove the value.
else if (!ReferenceEquals(value, _defaultValue))
{
- instance.SetEffectiveValue(entryIndex, dp: null, _globalIndex, metadata: null, value, BaseValueSourceInternal.Local);
+ instance.SetEffectiveValue(entryIndex, dp: null, GlobalIndex, metadata: null, value, BaseValueSourceInternal.Local);
_hasBeenSet = true;
}
else
@@ -66,7 +79,7 @@ public void SetValue(DependencyObject instance, T value)
}
/// <summary>
- /// Read the value of this field on a DependencyObject instance.
+ /// Read the value of this field on a DependencyObject instance.
/// </summary>
/// <param name="instance">The DependencyObject from which to get the value.</param>
/// <returns></returns>
@@ -76,7 +89,7 @@ public T GetValue(DependencyObject instance)
if (_hasBeenSet)
{
- EntryIndex entryIndex = instance.LookupEntry(_globalIndex);
+ EntryIndex entryIndex = instance.LookupEntry(GlobalIndex);
if (entryIndex.Found)
{
@@ -97,32 +110,16 @@ public T GetValue(DependencyObject instance)
/// <summary>
- /// Clear this field from the given DependencyObject instance.
+ /// Clear this field from the given DependencyObject instance.
/// </summary>
- /// <param name="instance"></param>
+ /// <param name="instance">An instance on which to clear the value from.</param>
public void ClearValue(DependencyObject instance)
{
ArgumentNullException.ThrowIfNull(instance);
- EntryIndex entryIndex = instance.LookupEntry(_globalIndex);
+ EntryIndex entryIndex = instance.LookupEntry(GlobalIndex);
instance.UnsetEffectiveValue(entryIndex, dp: null, metadata: null);
}
-
- internal int GlobalIndex
- {
- get
- {
- return _globalIndex;
- }
- }
-
- #region Private Fields
-
- private T _defaultValue;
- private int _globalIndex;
- private bool _hasBeenSet;
-
- #endregion
}
}