Refactoring with .NET 5 Unsafe APIs (#3510)

## Close #3509 
<!-- Add the relevant issue number after the "#" mentioned above (for ex: Fixes #1234) which will automatically close the issue once the PR is merged. -->

<!-- Add a brief overview here of the feature/bug & fix. -->

## PR Type
What kind of change does this PR introduce?
<!-- Please uncomment one or more that apply to this PR. -->

- Refactoring (no functional changes, no api changes)
<!-- - Build or CI related changes -->
<!-- - Documentation content changes -->
<!-- - Sample app changes -->
<!-- - Other... Please describe: -->


## What is the current behavior?
<!-- Please describe the current behavior that you are modifying, or link to a relevant issue. -->
There are a number of usages of `Unsafe.AsRef<T>(null)` and similar that are verbose.

## What is the new behavior?
<!-- Describe how was this issue resolved or changed? -->
These occurrences are replaced using the new `Unsafe.NullRef<T>()` and `Unsafe.IsNullRef<T>(...)` APIs.

## Notes

Leaving this as draft as the new `System.Runtime.CompilerServices.Unsafe` package is still in release candidate.

## PR Checklist

Please check if your PR fulfills the following requirements:

- [X] Tested code with current [supported SDKs](../readme.md#supported)
- [ ] ~~Pull Request has been submitted to the documentation repository [instructions](..\contributing.md#docs). Link: <!-- docs PR link -->~~
- [ ] ~~Sample in sample app has been added / updated (for bug fixes / features)~~
    - [ ] ~~Icon has been created (if new sample) following the [Thumbnail Style Guide and templates](https://github.com/windows-toolkit/WindowsCommunityToolkit-design-assets)~~
- [X] Tests for the changes have been added (for bug fixes / features) (if applicable)
- [X] Header has been added to all new source files (run *build/UpdateHeaders.bat*)
- [X] Contains **NO** breaking changes

Microsoft.Toolkit.HighPerformance/Box{T}.cs

@@ -78,7 +78,7 @@ public static Box<T> GetFrom(object obj)
  ThrowInvalidCastExceptionForGetFrom();
  }
 
- return Unsafe.As<Box<T>>(obj);
+ return Unsafe.As<Box<T>>(obj)!;
  }
 
  /// <summary>
@@ -94,7 +94,7 @@ public static Box<T> GetFrom(object obj)
  [MethodImpl(MethodImplOptions.AggressiveInlining)]
  public static Box<T> DangerousGetFrom(object obj)
  {
- return Unsafe.As<Box<T>>(obj);
+ return Unsafe.As<Box<T>>(obj)!;
  }
 
  /// <summary>
@@ -108,7 +108,7 @@ public static bool TryGetFrom(object obj, [NotNullWhen(true)] out Box<T>? box)
  {
  if (obj.GetType() == typeof(T))
  {
- box = Unsafe.As<Box<T>>(obj);
+ box = Unsafe.As<Box<T>>(obj)!;
 
  return true;
  }
@@ -145,7 +145,7 @@ public static implicit operator Box<T>(T value)
  // manually be implemented in the Box<T> type. For instance, boxing a float
  // and calling ToString() on it directly, on its boxed object or on a Box<T>
  // reference retrieved from it will produce the same result in all cases.
- return Unsafe.As<Box<T>>(value);
+ return Unsafe.As<Box<T>>(value)!;
  }
 
  /// <inheritdoc/>

Microsoft.Toolkit.HighPerformance/Buffers/StringPool.cs

@@ -422,11 +422,11 @@ public object SyncRoot
  /// <param name="value">The input <see cref="string"/> instance to cache.</param>
  /// <param name="hashcode">The precomputed hashcode for <paramref name="value"/>.</param>
  [MethodImpl(MethodImplOptions.AggressiveInlining)]
- public unsafe void Add(string value, int hashcode)
+ public void Add(string value, int hashcode)
  {
  ref string target = ref TryGet(value.AsSpan(), hashcode);
 
- if (Unsafe.AreSame(ref target, ref Unsafe.AsRef<string>(null)))
+ if (Unsafe.IsNullRef(ref target))
  {
  Insert(value, hashcode);
  }
@@ -443,11 +443,11 @@ public unsafe void Add(string value, int hashcode)
  /// <param name="hashcode">The precomputed hashcode for <paramref name="value"/>.</param>
  /// <returns>A <see cref="string"/> instance with the contents of <paramref name="value"/>.</returns>
  [MethodImpl(MethodImplOptions.AggressiveInlining)]
- public unsafe string GetOrAdd(string value, int hashcode)
+ public string GetOrAdd(string value, int hashcode)
  {
  ref string result = ref TryGet(value.AsSpan(), hashcode);
 
- if (!Unsafe.AreSame(ref result, ref Unsafe.AsRef<string>(null)))
+ if (!Unsafe.IsNullRef(ref result))
  {
  return result;
  }
@@ -464,11 +464,11 @@ public unsafe string GetOrAdd(string value, int hashcode)
  /// <param name="hashcode">The precomputed hashcode for <paramref name="span"/>.</param>
  /// <returns>A <see cref="string"/> instance with the contents of <paramref name="span"/>, cached if possible.</returns>
  [MethodImpl(MethodImplOptions.AggressiveInlining)]
- public unsafe string GetOrAdd(ReadOnlySpan<char> span, int hashcode)
+ public string GetOrAdd(ReadOnlySpan<char> span, int hashcode)
  {
  ref string result = ref TryGet(span, hashcode);
 
- if (!Unsafe.AreSame(ref result, ref Unsafe.AsRef<string>(null)))
+ if (!Unsafe.IsNullRef(ref result))
  {
  return result;
  }
@@ -488,11 +488,11 @@ public unsafe string GetOrAdd(ReadOnlySpan<char> span, int hashcode)
  /// <param name="value">The resulting cached <see cref="string"/> instance, if present</param>
  /// <returns>Whether or not the target <see cref="string"/> instance was found.</returns>
  [MethodImpl(MethodImplOptions.AggressiveInlining)]
- public unsafe bool TryGet(ReadOnlySpan<char> span, int hashcode, [NotNullWhen(true)] out string? value)
+ public bool TryGet(ReadOnlySpan<char> span, int hashcode, [NotNullWhen(true)] out string? value)
  {
  ref string result = ref TryGet(span, hashcode);
 
- if (!Unsafe.AreSame(ref result, ref Unsafe.AsRef<string>(null)))
+ if (!Unsafe.IsNullRef(ref result))
  {
  value = result;
 
@@ -527,7 +527,7 @@ public void Reset()
  private unsafe ref string TryGet(ReadOnlySpan<char> span, int hashcode)
  {
  ref MapEntry mapEntriesRef = ref this.mapEntries.DangerousGetReference();
- ref MapEntry entry = ref Unsafe.AsRef<MapEntry>(null);
+ ref MapEntry entry = ref Unsafe.NullRef<MapEntry>();
  int
  length = this.buckets.Length,
  bucketIndex = hashcode & (length - 1);
@@ -547,7 +547,7 @@ private unsafe ref string TryGet(ReadOnlySpan<char> span, int hashcode)
  }
  }
 
- return ref Unsafe.AsRef<string>(null);
+ return ref Unsafe.NullRef<string>();
  }
 
  /// <summary>

Microsoft.Toolkit.HighPerformance/Extensions/ArrayExtensions.1D.cs

@@ -31,7 +31,7 @@ public static partial class ArrayExtensions
  public static ref T DangerousGetReference<T>(this T[] array)
  {
 #if NETCORE_RUNTIME
- var arrayData = Unsafe.As<RawArrayData>(array);
+ var arrayData = Unsafe.As<RawArrayData>(array)!;
  ref T r0 = ref Unsafe.As<byte, T>(ref arrayData.Data);
 
  return ref r0;
@@ -55,7 +55,7 @@ public static ref T DangerousGetReference<T>(this T[] array)
  public static ref T DangerousGetReferenceAt<T>(this T[] array, int i)
  {
 #if NETCORE_RUNTIME
- var arrayData = Unsafe.As<RawArrayData>(array);
+ var arrayData = Unsafe.As<RawArrayData>(array)!;
  ref T r0 = ref Unsafe.As<byte, T>(ref arrayData.Data);
  ref T ri = ref Unsafe.Add(ref r0, (nint)(uint)i);
 

Microsoft.Toolkit.HighPerformance/Extensions/ArrayExtensions.2D.cs

@@ -33,7 +33,7 @@ public static partial class ArrayExtensions
  public static ref T DangerousGetReference<T>(this T[,] array)
  {
 #if NETCORE_RUNTIME
- var arrayData = Unsafe.As<RawArray2DData>(array);
+ var arrayData = Unsafe.As<RawArray2DData>(array)!;
  ref T r0 = ref Unsafe.As<byte, T>(ref arrayData.Data);
 
  return ref r0;
@@ -63,7 +63,7 @@ public static ref T DangerousGetReference<T>(this T[,] array)
  public static ref T DangerousGetReferenceAt<T>(this T[,] array, int i, int j)
  {
 #if NETCORE_RUNTIME
- var arrayData = Unsafe.As<RawArray2DData>(array);
+ var arrayData = Unsafe.As<RawArray2DData>(array)!;
  nint offset = ((nint)(uint)i * (nint)(uint)arrayData.Width) + (nint)(uint)j;
  ref T r0 = ref Unsafe.As<byte, T>(ref arrayData.Data);
  ref T ri = ref Unsafe.Add(ref r0, offset);

Microsoft.Toolkit.HighPerformance/Extensions/ArrayExtensions.3D.cs

@@ -32,7 +32,7 @@ public static partial class ArrayExtensions
  public static ref T DangerousGetReference<T>(this T[,,] array)
  {
 #if NETCORE_RUNTIME
- var arrayData = Unsafe.As<RawArray3DData>(array);
+ var arrayData = Unsafe.As<RawArray3DData>(array)!;
  ref T r0 = ref Unsafe.As<byte, T>(ref arrayData.Data);
 
  return ref r0;
@@ -63,7 +63,7 @@ public static ref T DangerousGetReference<T>(this T[,,] array)
  public static ref T DangerousGetReferenceAt<T>(this T[,,] array, int i, int j, int k)
  {
 #if NETCORE_RUNTIME
- var arrayData = Unsafe.As<RawArray3DData>(array);
+ var arrayData = Unsafe.As<RawArray3DData>(array)!;
  nint offset =
  ((nint)(uint)i * (nint)(uint)arrayData.Height * (nint)(uint)arrayData.Width) +
  ((nint)(uint)j * (nint)(uint)arrayData.Width) + (nint)(uint)k;

Microsoft.Toolkit.HighPerformance/Extensions/ObjectExtensions.cs

@@ -31,7 +31,7 @@ public static class ObjectExtensions
  [MethodImpl(MethodImplOptions.AggressiveInlining)]
  public static IntPtr DangerousGetObjectDataByteOffset<T>(this object obj, ref T data)
  {
- var rawObj = Unsafe.As<RawObjectData>(obj);
+ var rawObj = Unsafe.As<RawObjectData>(obj)!;
  ref byte r0 = ref rawObj.Data;
  ref byte r1 = ref Unsafe.As<T, byte>(ref data);
 
@@ -55,7 +55,7 @@ public static IntPtr DangerousGetObjectDataByteOffset<T>(this object obj, ref T
  [MethodImpl(MethodImplOptions.AggressiveInlining)]
  public static ref T DangerousGetObjectDataReferenceAt<T>(this object obj, IntPtr offset)
  {
- var rawObj = Unsafe.As<RawObjectData>(obj);
+ var rawObj = Unsafe.As<RawObjectData>(obj)!;
  ref byte r0 = ref rawObj.Data;
  ref byte r1 = ref Unsafe.AddByteOffset(ref r0, offset);
  ref T r2 = ref Unsafe.As<byte, T>(ref r1);

Microsoft.Toolkit.HighPerformance/Extensions/StringExtensions.cs

@@ -31,7 +31,7 @@ public static ref char DangerousGetReference(this string text)
 #if NETCOREAPP3_1
  return ref Unsafe.AsRef(text.GetPinnableReference());
 #elif NETCOREAPP2_1
- var stringData = Unsafe.As<RawStringData>(text);
+ var stringData = Unsafe.As<RawStringData>(text)!;
 
  return ref stringData.Data;
 #else
@@ -53,7 +53,7 @@ public static ref char DangerousGetReferenceAt(this string text, int i)
 #if NETCOREAPP3_1
  ref char r0 = ref Unsafe.AsRef(text.GetPinnableReference());
 #elif NETCOREAPP2_1
- ref char r0 = ref Unsafe.As<RawStringData>(text).Data;
+ ref char r0 = ref Unsafe.As<RawStringData>(text)!.Data;
 #else
  ref char r0 = ref MemoryMarshal.GetReference(text.AsSpan());
 #endif

Microsoft.Toolkit.HighPerformance/Memory/Memory2D{T}.cs

@@ -772,7 +772,7 @@ public bool TryGetMemory(out Memory<T> memory)
  }
  else if (typeof(T) == typeof(char) && this.instance.GetType() == typeof(string))
  {
- string text = Unsafe.As<string>(this.instance);
+ string text = Unsafe.As<string>(this.instance)!;
  int index = text.AsSpan().IndexOf(in text.DangerousGetObjectDataReferenceAt<char>(this.offset));
  ReadOnlyMemory<char> temp = text.AsMemory(index, (int)Length);
 
@@ -786,16 +786,13 @@ public bool TryGetMemory(out Memory<T> memory)
  }
  else if (this.instance is MemoryManager<T> memoryManager)
  {
- unsafe
- {
- // If the object is a MemoryManager<T>, just slice it as needed
- memory = memoryManager.Memory.Slice((int)(void*)this.offset, this.height * this.width);
- }
+ // If the object is a MemoryManager<T>, just slice it as needed
+ memory = memoryManager.Memory.Slice((int)(nint)this.offset, this.height * this.width);
  }
  else if (this.instance.GetType() == typeof(T[]))
  {
  // If it's a T[] array, also handle the initial offset
- T[] array = Unsafe.As<T[]>(this.instance);
+ T[] array = Unsafe.As<T[]>(this.instance)!;
  int index = array.AsSpan().IndexOf(ref array.DangerousGetObjectDataReferenceAt<T>(this.offset));
 
  memory = array.AsMemory(index, this.height * this.width);

Microsoft.Toolkit.HighPerformance/Memory/ReadOnlyMemory2D{T}.cs

@@ -794,24 +794,21 @@ public bool TryGetMemory(out ReadOnlyMemory<T> memory)
  // difference between the start of the Span<char> (which directly wraps just the actual character data
  // within the string), and the input reference, which we can get from the byte offset in use. The result
  // is the character index which we can use to create the final Memory<char> instance.
- string text = Unsafe.As<string>(this.instance);
+ string text = Unsafe.As<string>(this.instance)!;
  int index = text.AsSpan().IndexOf(in text.DangerousGetObjectDataReferenceAt<char>(this.offset));
  ReadOnlyMemory<char> temp = text.AsMemory(index, (int)Length);
 
  memory = Unsafe.As<ReadOnlyMemory<char>, ReadOnlyMemory<T>>(ref temp);
  }
  else if (this.instance is MemoryManager<T> memoryManager)
  {
- unsafe
- {
- // If the object is a MemoryManager<T>, just slice it as needed
- memory = memoryManager.Memory.Slice((int)(void*)this.offset, this.height * this.width);
- }
+ // If the object is a MemoryManager<T>, just slice it as needed
+ memory = memoryManager.Memory.Slice((int)(nint)this.offset, this.height * this.width);
  }
  else if (this.instance.GetType() == typeof(T[]))
  {
  // If it's a T[] array, also handle the initial offset
- T[] array = Unsafe.As<T[]>(this.instance);
+ T[] array = Unsafe.As<T[]>(this.instance)!;
  int index = array.AsSpan().IndexOf(ref array.DangerousGetObjectDataReferenceAt<T>(this.offset));
 
  memory = array.AsMemory(index, this.height * this.width);

Microsoft.Toolkit.HighPerformance/Microsoft.Toolkit.HighPerformance.csproj

@@ -41,7 +41,7 @@
  <PackageReference Include="System.Numerics.Vectors" Version="4.5.0" />
  <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" />
  <PackageReference Include="System.Threading.Tasks.Parallel" Version="4.3.0" />
- <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.7.1" />
+ <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="5.0.0" />
  </ItemGroup>
  </When>
  <When Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
@@ -51,14 +51,14 @@
  <PackageReference Include="Microsoft.Bcl.HashCode" Version="1.1.0" />
  <PackageReference Include="System.Memory" Version="4.5.4" />
  <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" />
- <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.7.1" />
+ <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="5.0.0" />
  </ItemGroup>
  </When>
  <When Condition=" '$(TargetFramework)' == 'netstandard2.1' ">
  <ItemGroup>
 
  <!-- .NET Standard 2.1 doesn't have the Unsafe type -->
- <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.7.1" />
+ <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="5.0.0" />
  </ItemGroup>
  <PropertyGroup>
 
@@ -76,6 +76,9 @@
  </PropertyGroup>
  </When>
  <When Condition=" '$(TargetFramework)' == 'netcoreapp3.1' ">
+ <ItemGroup>
+ <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="5.0.0" />
+ </ItemGroup>
  <PropertyGroup>
 
  <!-- NETCORE_RUNTIME: to avoid issues with APIs that assume a specific memory layout, we define a
@@ -89,7 +92,7 @@
  </When>
  <When Condition=" '$(TargetFramework)' == 'netcoreapp2.1' ">
  <ItemGroup>
- <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.7.1" />
+ <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="5.0.0" />
  </ItemGroup>
  <PropertyGroup>
  <DefineConstants>SPAN_RUNTIME_SUPPORT;NETCORE_RUNTIME</DefineConstants>

Microsoft.Toolkit.Uwp/Helpers/ColorHelper.cs

@@ -3,7 +3,9 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Globalization;
 using System.Reflection;
+using Microsoft.Toolkit.Diagnostics;
 using Windows.UI;
 using Color = Windows.UI.Color;
 
@@ -22,10 +24,7 @@ public static class ColorHelper
  /// <returns>The created <see cref="Color"/>.</returns>
  public static Color ToColor(this string colorString)
  {
- if (string.IsNullOrEmpty(colorString))
- {
- throw new ArgumentException(nameof(colorString));
- }
+ Guard.IsNotNullOrEmpty(colorString, nameof(colorString));
 
  if (colorString[0] == '#')
  {
@@ -80,8 +79,7 @@ public static Color ToColor(this string colorString)
  return Color.FromArgb(255, r, g, b);
  }
 
- default:
- throw new FormatException(string.Format("The {0} string passed in the colorString argument is not a recognized Color format.", colorString));
+ default: return ThrowHelper.ThrowFormatException<Color>("The string passed in the colorString argument is not a recognized Color format.");
  }
  }
 
@@ -91,24 +89,24 @@ public static Color ToColor(this string colorString)
 
  if (values.Length == 4)
  {
- var scA = double.Parse(values[0].Substring(3));
- var scR = double.Parse(values[1]);
- var scG = double.Parse(values[2]);
- var scB = double.Parse(values[3]);
+ var scA = double.Parse(values[0].Substring(3), CultureInfo.InvariantCulture);
+ var scR = double.Parse(values[1], CultureInfo.InvariantCulture);
+ var scG = double.Parse(values[2], CultureInfo.InvariantCulture);
+ var scB = double.Parse(values[3], CultureInfo.InvariantCulture);
 
  return Color.FromArgb((byte)(scA * 255), (byte)(scR * 255), (byte)(scG * 255), (byte)(scB * 255));
  }
 
  if (values.Length == 3)
  {
- var scR = double.Parse(values[0].Substring(3));
- var scG = double.Parse(values[1]);
- var scB = double.Parse(values[2]);
+ var scR = double.Parse(values[0].Substring(3), CultureInfo.InvariantCulture);
+ var scG = double.Parse(values[1], CultureInfo.InvariantCulture);
+ var scB = double.Parse(values[2], CultureInfo.InvariantCulture);
 
  return Color.FromArgb(255, (byte)(scR * 255), (byte)(scG * 255), (byte)(scB * 255));
  }
 
- throw new FormatException(string.Format("The {0} string passed in the colorString argument is not a recognized Color format (sc#[scA,]scR,scG,scB).", colorString));
+ return ThrowHelper.ThrowFormatException<Color>("The string passed in the colorString argument is not a recognized Color format (sc#[scA,]scR,scG,scB).");
  }
 
  var prop = typeof(Colors).GetTypeInfo().GetDeclaredProperty(colorString);
@@ -118,7 +116,7 @@ public static Color ToColor(this string colorString)
  return (Color)prop.GetValue(null);
  }
 
- throw new FormatException(string.Format("The {0} string passed in the colorString argument is not a recognized Color.", colorString));
+ return ThrowHelper.ThrowFormatException<Color>("The string passed in the colorString argument is not a recognized Color.");
  }
 
  /// <summary>

UnitTests/UnitTests.HighPerformance.NetCore/UnitTests.HighPerformance.NetCore.csproj

@@ -9,7 +9,7 @@
 
  <!-- .NET Core 2.1 doesn't have the Unsafe type -->
  <ItemGroup Condition=" '$(TargetFramework)' == 'netcoreapp2.1' ">
- <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="4.7.1" />
+ <PackageReference Include="System.Runtime.CompilerServices.Unsafe" Version="5.0.0" />
  </ItemGroup>
 
  <ItemGroup>

UnitTests/UnitTests.HighPerformance.UWP/UnitTests.HighPerformance.UWP.csproj

@@ -160,7 +160,7 @@
  <Version>1.4.0</Version>
  </PackageReference>
  <PackageReference Include="System.Runtime.CompilerServices.Unsafe">
- <Version>4.7.1</Version>
+ <Version>5.0.0</Version>
  </PackageReference>
  </ItemGroup>
  <ItemGroup>