Cleaned up code for old runtimes.

Package/Core/Collections/Internal/ConcurrentQueueSegmentInternal.cs

@@ -4,13 +4,7 @@
 #undef PROMISE_DEBUG
 #endif
 
-using System;
-// ArrayPool for old runtime is in Proto.Promises.Collections namespace.
-#if (NETCOREAPP || NETSTANDARD2_0_OR_GREATER || UNITY_2021_2_OR_NEWER)
 using System.Buffers;
-#else
-using Proto.Promises.Collections;
-#endif
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;

Package/Core/Collections/Internal/PoolBackedDequeInternal.cs

@@ -5,12 +5,7 @@
 #endif
 
 using System;
-// ArrayPool for old runtime is in Proto.Promises.Collections namespace.
-#if (NETCOREAPP || NETSTANDARD2_0_OR_GREATER || UNITY_2021_2_OR_NEWER)
 using System.Buffers;
-#else
-using Proto.Promises.Collections;
-#endif
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 

Package/Core/Collections/TempCollection.cs

@@ -5,9 +5,7 @@
 #endif
 
 using System;
-#if UNITY_2021_2_OR_NEWER || !UNITY_2018_3_OR_NEWER
 using System.Buffers;
-#endif
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;

Package/Core/ForOldRuntime/ArrayPool/ArrayPool.cs

@@ -1,13 +1,12 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-// Different namespace to avoid collisions if someone else brings in the ArrayPool package.
-namespace Proto.Promises.Collections
-{
-    // We reference the nuget package for the nuget builds, but to not have any nuget dependencies in Unity, we include the source.
-    // ArrayPool was added in netstandard2.1, so we only need this in Unity versions older than 2021.2.
+// We reference the nuget package for the nuget builds, but to not have any nuget dependencies in Unity, we include the source.
+// ArrayPool was added in netstandard2.1, so we only need this in Unity versions older than 2021.2.
 #if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
 
+namespace System.Buffers
+{
     /// <summary>
     /// Provides a resource pool that enables reusing instances of arrays.
     /// </summary>
@@ -25,7 +24,7 @@ internal abstract class ArrayPool<T>
     {
         // Store the shared ArrayPool in a field of its derived sealed type so the Jit can "see" the exact type
         // when the Shared property is inlined which will allow it to devirtualize calls made on it.
-        private static readonly TlsOverPerCoreLockedStacksArrayPool<T> s_shared = new TlsOverPerCoreLockedStacksArrayPool<T>();
+        private static readonly SharedArrayPool<T> s_shared = new SharedArrayPool<T>();
 
         /// <summary>
         /// Retrieves a shared <see cref="ArrayPool{T}"/> instance.
@@ -81,6 +80,6 @@ internal abstract class ArrayPool<T>
         /// </remarks>
         public abstract void Return(T[] array, bool clearArray = false);
     }
+}
 
-#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-}
+#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER

Package/Core/ForOldRuntime/ArrayPool/TlsOverPerCoreLockedStacksArrayPool.cs → Package/Core/ForOldRuntime/ArrayPool/SharedArrayPool.cs

@@ -3,19 +3,13 @@
 
 // Modified to work in Unity/netstandard2.0 without using the nuget package.
 // Hooks up to Promise.Manager.ClearObjectPool() event instead of using Gen2GC callbacks.
-
 #if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
+
 using System.Runtime.CompilerServices;
 using System.Threading;
-#endif
 
-namespace Proto.Promises.Collections
+namespace System.Buffers
 {
-#if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-
     /// <summary>
     /// Provides an ArrayPool implementation meant to be used as the singleton returned from ArrayPool.Shared.
     /// </summary>
@@ -26,7 +20,7 @@ namespace Proto.Promises.Collections
     /// checking its processor number, because multiple threads could interleave on the same core, and because
     /// a thread is allowed to check other core's buckets if its core's bucket is empty/full.
     /// </remarks>
-    internal sealed partial class TlsOverPerCoreLockedStacksArrayPool<T> : ArrayPool<T>
+    internal sealed partial class SharedArrayPool<T> : ArrayPool<T>
     {
         /// <summary>The number of buckets (array sizes) in the pool, one for each array length, starting from length 16.</summary>
         private const int NumBuckets = 17; // Utilities.SelectBucketIndex(2*1024*1024)
@@ -44,7 +38,7 @@ internal sealed partial class TlsOverPerCoreLockedStacksArrayPool<T> : ArrayPool
         private readonly PerCoreLockedStacks[] _buckets = new PerCoreLockedStacks[NumBuckets];
 
         /// <summary>Initialize the pool.</summary>
-        public TlsOverPerCoreLockedStacksArrayPool()
+        public SharedArrayPool()
         {
             var sizes = new int[NumBuckets];
             for (int i = 0; i < sizes.Length; i++)
@@ -54,7 +48,7 @@ public TlsOverPerCoreLockedStacksArrayPool()
             _bucketArraySizes = sizes;
 
             // Hook up to Promise.Manage.ClearObjectPool() event.
-            Internal.AddClearPoolListener(Trim);
+            Proto.Promises.Internal.AddClearPoolListener(Trim);
         }
 
         /// <summary>Allocate a new PerCoreLockedStacks and try to store it into the <see cref="_buckets"/> array.</summary>
@@ -271,6 +265,6 @@ public void Trim(uint tickCount, int id, int bucketSize)
             }
         }
     }
+}
 
-#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-}
+#endif

Package/Core/ForOldRuntime/ArrayPool/Utilities.cs

@@ -2,15 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 #if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-using System;
+
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
-#endif
 
-namespace Proto.Promises.Collections
+namespace System.Buffers
 {
-#if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-
     internal static class Utilities
     {
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -46,6 +43,6 @@ private static int Log2SoftwareFallback(uint value)
             return (int) Math.Log(value, 2);
         }
     }
+}
 
-#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-}
+#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER

Package/Core/ForOldRuntime/Span/ArraySortHelper.cs

@@ -2,6 +2,9 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+// TODO: Unity hasn't adopted .Net 5+ yet, and they usually use different compilation symbols than .Net SDK, so we'll have to update the compilation symbols here once Unity finally does adopt it.
+#if !NET5_0_OR_GREATER
+
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -12,8 +15,6 @@
 // Using Proto.Promises namespace instead of the original System.Runtime.CompilerServices, and wrapped in Internal class.
 namespace Proto.Promises
 {
-    // TODO: Unity hasn't adopted .Net 5+ yet, and they usually use different compilation symbols than .Net SDK, so we'll have to update the compilation symbols here once Unity finally does adopt it.
-#if !NET5_0_OR_GREATER
     partial class Internal
     {
         internal static class IntrospectiveSortUtilities
@@ -220,5 +221,6 @@ private static void InsertionSort<TComparer>(Span<T> keys, TComparer comparer) w
             }
         }
     }
-#endif // !NET5_0_OR_GREATER
 }
+
+#endif // !NET5_0_OR_GREATER

Package/Core/ForOldRuntime/Span/ReadOnlySpan.cs

@@ -1,3 +1,7 @@
+// ReadOnlySpan is part of netstandard2.1, and we use the Span nuget package in netstandard2.0,
+// but we don't use nuget packages in Unity, so we have to implement it ourselves.
+#if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
+
 using System.ComponentModel;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
@@ -6,9 +10,6 @@
 
 namespace System
 {
-    // ReadOnlySpan is part of netstandard2.1, and we use the Span nuget package in netstandard2.0,
-    // but we don't use nuget packages in Unity, so we have to implement it ourselves.
-#if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
     internal readonly ref struct ReadOnlySpan<T>
     {
         private readonly Span<T> _span;
@@ -110,5 +111,6 @@ public T Current
 
         internal void CopyTo(Span<T> destination) => _span.CopyTo(destination);
     }
-#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-}
+}
+
+#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER

Package/Core/ForOldRuntime/Span/Span.cs

@@ -1,3 +1,7 @@
+// Span is part of netstandard2.1, and we use the Span nuget package in netstandard2.0,
+// but we don't use nuget packages in Unity, so we have to implement it ourselves.
+#if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
+
 using System.ComponentModel;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
@@ -6,9 +10,6 @@
 
 namespace System
 {
-    // Span is part of netstandard2.1, and we use the Span nuget package in netstandard2.0,
-    // but we don't use nuget packages in Unity, so we have to implement it ourselves.
-#if UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
     internal readonly ref struct Span<T>
     {
         // We only use it as a view over an array, not using pointers.
@@ -133,5 +134,6 @@ internal void CopyTo(Span<T> destination)
             }
         }
     }
-#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER
-}
+}
+
+#endif // UNITY_2018_3_OR_NEWER && !UNITY_2021_2_OR_NEWER

Package/Core/ForOldRuntime/Span/SpanExtensions.cs

@@ -1,12 +1,13 @@
+// TODO: Unity hasn't adopted .Net 5+ yet, and they usually use different compilation symbols than .Net SDK, so we'll have to update the compilation symbols here once Unity finally does adopt it.
+#if !NET5_0_OR_GREATER
+
 using System;
 using System.Collections.Generic;
 
 namespace Proto.Promises
 {
     partial class Internal
     {
-        // TODO: Unity hasn't adopted .Net 5+ yet, and they usually use different compilation symbols than .Net SDK, so we'll have to update the compilation symbols here once Unity finally does adopt it.
-#if !NET5_0_OR_GREATER
         // Span Sort extensions only exist in .Net 5+, so we pulled the ArraySortHelper code directly from the dotnet/runtime repository.
         // We could use Array.Sort, but depending on the runtime, it allocates on one overload or the other.
         // Since we're targeting netstandard which can be used in any runtime, we want to avoid any allocations,
@@ -22,6 +23,7 @@ public static void Sort<T>(this Span<T> span)
         // AsSpan extension exists in netstandard2.1 and in the Span nuget package. We only add this in Unity where we're not using nuget packages.
         public static Span<T> AsSpan<T>(this T[] array, int start)
             => new Span<T>(array, start, array.Length);
-#endif
     }
-}
+}
+
+#endif

Package/Core/ForOldRuntime/StackTraceHiddenAttribute.cs

@@ -1,9 +1,7 @@
 // TODO: Unity hasn't adopted .Net 6+ yet, and they usually use different compilation symbols than .Net SDK, so we'll have to update the compilation symbols here once Unity finally does adopt it.
 #if !NET6_0_OR_GREATER
 
-using System;
-
-namespace Proto.Promises
+namespace System.Diagnostics
 {
     // This doesn't actually do anything before .Net 6, this is just to make it so we don't need to #if NET6_0_OR_GREATER at every place the attribute is used.
     [AttributeUsage(AttributeTargets.Class | AttributeTargets.Constructor | AttributeTargets.Method | AttributeTargets.Struct, Inherited = false)]

Package/Core/Linq/Internal/PoolBackedQueueInternal.cs

@@ -5,12 +5,7 @@
 #endif
 
 using System;
-// ArrayPool for old runtime is in Proto.Promises.Collections namespace.
-#if (NETCOREAPP || NETSTANDARD2_0_OR_GREATER || UNITY_2021_2_OR_NEWER)
 using System.Buffers;
-#else
-using Proto.Promises.Collections;
-#endif
 using System.Diagnostics;
 using System.Runtime.CompilerServices;