Add ArrayPool<T>.Return(T[], int) extension

hendriklhf · hendriklhf · commit 3cd9a0369f5b · 2025-09-21T14:50:55.000+02:00
diff --git a/src/Components/Components/src/Microsoft.AspNetCore.Components.csproj b/src/Components/Components/src/Microsoft.AspNetCore.Components.csproj
@@ -26,6 +26,7 @@
     <Compile Include="$(SharedSourceRoot)UrlDecoder\UrlDecoder.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Metrics\MetricsConstants.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Components\ComponentsActivityLinkStore.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <Import Project="Microsoft.AspNetCore.Components.Routing.targets" />
diff --git a/src/Components/Components/src/NavigationManager.cs b/src/Components/Components/src/NavigationManager.cs
@@ -447,8 +447,7 @@ protected async ValueTask<bool> NotifyLocationChangingAsync(string uri, string?
                 }
                 finally
                 {
-                    locationChangingHandlersCopy.AsSpan(0, handlerCount).Clear();
-                    ArrayPool<Func<LocationChangingContext, ValueTask>>.Shared.Return(locationChangingHandlersCopy);
+                    ArrayPool<Func<LocationChangingContext, ValueTask>>.Shared.Return(locationChangingHandlersCopy, handlerCount);
                 }
             }
 
diff --git a/src/Components/Endpoints/src/FormMapping/Converters/CollectionAdapters/ArrayPoolBufferAdapter.cs b/src/Components/Endpoints/src/FormMapping/Converters/CollectionAdapters/ArrayPoolBufferAdapter.cs
@@ -21,10 +21,12 @@ public static PooledBuffer Add(ref PooledBuffer buffer, TElement element)
 
             if (RuntimeHelpers.IsReferenceOrContainsReferences<TElement>())
             {
-                buffer.Data.AsSpan(0, buffer.Count).Clear();
+                ArrayPool<TElement>.Shared.Return(buffer.Data, buffer.Count);
+            }
+            else
+            {
+                ArrayPool<TElement>.Shared.Return(buffer.Data);
             }
-
-            ArrayPool<TElement>.Shared.Return(buffer.Data);
 
             buffer.Data = newBuffer;
         }
@@ -39,10 +41,12 @@ public static TCollection ToResult(PooledBuffer buffer)
 
         if (RuntimeHelpers.IsReferenceOrContainsReferences<TElement>())
         {
-            buffer.Data.AsSpan(0, buffer.Count).Clear();
+            ArrayPool<TElement>.Shared.Return(buffer.Data, buffer.Count);
+        }
+        else
+        {
+            ArrayPool<TElement>.Shared.Return(buffer.Data);
         }
-
-        ArrayPool<TElement>.Shared.Return(buffer.Data);
 
         return result;
     }
diff --git a/src/Components/Endpoints/src/FormMapping/PrefixResolver.cs b/src/Components/Endpoints/src/FormMapping/PrefixResolver.cs
@@ -38,8 +38,7 @@ public void Dispose()
     {
         if (_sortedKeys != null)
         {
-            _sortedKeys.AsSpan(0, _length).Clear();
-            ArrayPool<FormKey>.Shared.Return(_sortedKeys);
+            ArrayPool<FormKey>.Shared.Return(_sortedKeys, _length);
         }
     }
 
diff --git a/src/Components/Endpoints/src/Microsoft.AspNetCore.Components.Endpoints.csproj b/src/Components/Endpoints/src/Microsoft.AspNetCore.Components.Endpoints.csproj
@@ -35,9 +35,8 @@
     <Compile Include="$(SharedSourceRoot)LinkerFlags.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Components\ComponentsActivityLinkStore.cs" LinkBase="Shared" />
     <Compile Include="$(ComponentsSharedSourceRoot)src\HotReloadManager.cs" LinkBase="HotReload" />
-
     <Compile Include="$(SharedSourceRoot)PropertyHelper\**\*.cs" />
-
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/Http/Http.Abstractions/src/Microsoft.AspNetCore.Http.Abstractions.csproj b/src/Http/Http.Abstractions/src/Microsoft.AspNetCore.Http.Abstractions.csproj
@@ -32,6 +32,7 @@ Microsoft.AspNetCore.Http.HttpResponse</Description>
     <Compile Include="$(SharedSourceRoot)Debugger\DictionaryItemDebugView.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Debugger\DictionaryDebugView.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)ValueStringBuilder\ValueListBuilder.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/Middleware/OutputCaching/src/Microsoft.AspNetCore.OutputCaching.csproj b/src/Middleware/OutputCaching/src/Microsoft.AspNetCore.OutputCaching.csproj
@@ -23,6 +23,7 @@
 
   <ItemGroup>
     <Compile Include="$(RepoRoot)src\Shared\TaskToApm.cs" Link="Streams\TaskToApm.cs" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
 </Project>
diff --git a/src/Middleware/OutputCaching/src/OutputCacheEntryFormatter.cs b/src/Middleware/OutputCaching/src/OutputCacheEntryFormatter.cs
@@ -46,15 +46,11 @@ public static async ValueTask StoreAsync(string key, OutputCacheEntry value, Has
         {
             if (store is IOutputCacheBufferStore bufferStore)
             {
-                await bufferStore.SetAsync(key, new(buffer.GetCommittedMemory()), CopyToLeasedMemory(tags, out var lease), duration, cancellationToken);
+                ReadOnlyMemory<string> leasedTags = CopyToLeasedMemory(tags, out var lease);
+                await bufferStore.SetAsync(key, new(buffer.GetCommittedMemory()), leasedTags, duration, cancellationToken);
                 if (lease is not null)
                 {
-                    if (tags is not null)
-                    {
-                        lease.AsSpan(0, tags.Count).Clear();
-                    }
-
-                    ArrayPool<string>.Shared.Return(lease);
+                    ArrayPool<string>.Shared.Return(lease, leasedTags.Length);
                 }
             }
             else
diff --git a/src/Middleware/OutputCaching/src/RecyclableArrayBufferWriter.cs b/src/Middleware/OutputCaching/src/RecyclableArrayBufferWriter.cs
@@ -40,10 +40,12 @@ public void Dispose()
         {
             if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())
             {
-                tmp.AsSpan(0, count).Clear();
+                ArrayPool<T>.Shared.Return(tmp, count);
+            }
+            else
+            {
+                ArrayPool<T>.Shared.Return(tmp);
             }
-
-            ArrayPool<T>.Shared.Return(tmp);
         }
     }
 
@@ -129,10 +131,12 @@ private void CheckAndResizeBuffer(int sizeHint)
             {
                 if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())
                 {
-                    oldArray.AsSpan(0, _index).Clear();
+                    ArrayPool<T>.Shared.Return(oldArray, _index);
+                }
+                else
+                {
+                    ArrayPool<T>.Shared.Return(oldArray);
                 }
-
-                ArrayPool<T>.Shared.Return(oldArray);
             }
         }
 
diff --git a/src/Middleware/WebSockets/src/Microsoft.AspNetCore.WebSockets.csproj b/src/Middleware/WebSockets/src/Microsoft.AspNetCore.WebSockets.csproj
@@ -19,6 +19,7 @@
 
   <ItemGroup>
     <Compile Include="$(SharedSourceRoot)ValueStringBuilder\**\*.cs" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/Mvc/Mvc.NewtonsoftJson/src/JsonArrayPool.cs b/src/Mvc/Mvc.NewtonsoftJson/src/JsonArrayPool.cs
@@ -29,9 +29,11 @@ public void Return(T[]? array)
 
         if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())
         {
-            array.AsSpan().Clear();
+            _inner.Return(array, array.Length);
+        }
+        else
+        {
+            _inner.Return(array);
         }
-
-        _inner.Return(array);
     }
 }
diff --git a/src/Mvc/Mvc.NewtonsoftJson/src/Microsoft.AspNetCore.Mvc.NewtonsoftJson.csproj b/src/Mvc/Mvc.NewtonsoftJson/src/Microsoft.AspNetCore.Mvc.NewtonsoftJson.csproj
@@ -26,6 +26,7 @@
     <Compile Include="..\..\Mvc.Core\src\Infrastructure\AsyncEnumerableReader.cs" />
     <Compile Include="$(SharedSourceRoot)ThrowHelpers\ArgumentNullThrowHelper.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)CallerArgument\CallerArgumentExpressionAttribute.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/Shared/Buffers/ArrayPoolExtensions.cs b/src/Shared/Buffers/ArrayPoolExtensions.cs
@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Buffers;
+
+internal static class ArrayPoolExtensions
+{
+    public static void Return<T>(this ArrayPool<T> pool, T[] array, int lengthToClear)
+    {
+        array.AsSpan(0, lengthToClear).Clear();
+        pool.Return(array);
+    }
+}
diff --git a/src/Shared/ValueStringBuilder/ValueListBuilder.cs b/src/Shared/ValueStringBuilder/ValueListBuilder.cs
@@ -63,10 +63,12 @@ public void Dispose()
 
             if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())
             {
-                toReturn.AsSpan(0, _pos).Clear();
+                ArrayPool<T>.Shared.Return(toReturn, _pos);
+            }
+            else
+            {
+                ArrayPool<T>.Shared.Return(toReturn);
             }
-
-            ArrayPool<T>.Shared.Return(toReturn);
         }
     }
 
@@ -103,10 +105,12 @@ private void Grow(int additionalCapacityRequired = 1)
         {
             if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())
             {
-                toReturn.AsSpan(0, _pos).Clear();
+                ArrayPool<T>.Shared.Return(toReturn, _pos);
+            }
+            else
+            {
+                ArrayPool<T>.Shared.Return(toReturn);
             }
-
-            ArrayPool<T>.Shared.Return(toReturn);
         }
     }
 }
diff --git a/src/Shared/test/Shared.Tests/ArrayPoolExtensionsTests.cs b/src/Shared/test/Shared.Tests/ArrayPoolExtensionsTests.cs
@@ -0,0 +1,21 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Buffers;
+
+public sealed class ArrayPoolExtensionsTests
+{
+    [Fact]
+    public void Return_PartiallyClearsArray_WithSpecifiedLengthToClear()
+    {
+        ArrayPool<int> pool = ArrayPool<int>.Create();
+        int[] array = pool.Rent(64);
+
+        array.AsSpan().Fill(int.MaxValue);
+
+        pool.Return(array, 42);
+
+        Assert.True(array.AsSpan(0, 42).IndexOfAnyExcept(0) < 0);
+        Assert.True(array.AsSpan(42).IndexOfAnyExcept(int.MaxValue) < 0);
+    }
+}
diff --git a/src/Shared/test/Shared.Tests/Microsoft.AspNetCore.Shared.Tests.csproj b/src/Shared/test/Shared.Tests/Microsoft.AspNetCore.Shared.Tests.csproj
@@ -42,6 +42,7 @@
     <Compile Include="$(SharedSourceRoot)Debugger\DictionaryItemDebugView.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Debugger\DictionaryDebugView.cs" LinkBase="Shared" />
     <Compile Include="$(SharedSourceRoot)Debugger\StringValuesDictionaryDebugView.cs" LinkBase="Shared" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/SignalR/common/Protocols.NewtonsoftJson/src/Microsoft.AspNetCore.SignalR.Protocols.NewtonsoftJson.csproj b/src/SignalR/common/Protocols.NewtonsoftJson/src/Microsoft.AspNetCore.SignalR.Protocols.NewtonsoftJson.csproj
@@ -18,6 +18,7 @@
     <Compile Include="$(SignalRSharedSourceRoot)Utf8BufferTextWriter.cs" Link="Utf8BufferTextWriter.cs" />
     <Compile Include="$(SignalRSharedSourceRoot)MemoryBufferWriter.cs" Link="MemoryBufferWriter.cs" />
     <Compile Include="$(SignalRSharedSourceRoot)TryGetReturnType.cs" Link="TryGetReturnType.cs" />
+    <Compile Include="$(SharedSourceRoot)Buffers\ArrayPoolExtensions.cs" LinkBase="Shared" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/SignalR/common/Shared/JsonUtils.cs b/src/SignalR/common/Shared/JsonUtils.cs
@@ -223,10 +223,12 @@ public void Return(T[]? array)
             if (!typeof(T).IsPrimitive)
 #endif
             {
-                array.AsSpan().Clear();
+                _inner.Return(array, array.Length);
+            }
+            else
+            {
+                _inner.Return(array);
             }
-
-            _inner.Return(array);
         }
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -447,8 +447,7 @@ protected async ValueTask<bool> NotifyLocationChangingAsync(string uri, string?`
`447`	`447`	`}`
`448`	`448`	`finally`
`449`	`449`	`{`
`450`		`- locationChangingHandlersCopy.AsSpan(0, handlerCount).Clear();`
`451`		`- ArrayPool<Func<LocationChangingContext, ValueTask>>.Shared.Return(locationChangingHandlersCopy);`
	`450`	`+ ArrayPool<Func<LocationChangingContext, ValueTask>>.Shared.Return(locationChangingHandlersCopy, handlerCount);`
`452`	`451`	`}`
`453`	`452`	`}`
`454`	`453`
Original file line number	Diff line number	Diff line change
`@@ -21,10 +21,12 @@ public static PooledBuffer Add(ref PooledBuffer buffer, TElement element)`
`21`	`21`
`22`	`22`	`if (RuntimeHelpers.IsReferenceOrContainsReferences<TElement>())`
`23`	`23`	`{`
`24`		`- buffer.Data.AsSpan(0, buffer.Count).Clear();`
	`24`	`+ ArrayPool<TElement>.Shared.Return(buffer.Data, buffer.Count);`
	`25`	`+ }`
	`26`	`+ else`
	`27`	`+ {`
	`28`	`+ ArrayPool<TElement>.Shared.Return(buffer.Data);`
`25`	`29`	`}`
`26`		`-`
`27`		`- ArrayPool<TElement>.Shared.Return(buffer.Data);`
`28`	`30`
`29`	`31`	`buffer.Data = newBuffer;`
`30`	`32`	`}`
`@@ -39,10 +41,12 @@ public static TCollection ToResult(PooledBuffer buffer)`
`39`	`41`
`40`	`42`	`if (RuntimeHelpers.IsReferenceOrContainsReferences<TElement>())`
`41`	`43`	`{`
`42`		`- buffer.Data.AsSpan(0, buffer.Count).Clear();`
	`44`	`+ ArrayPool<TElement>.Shared.Return(buffer.Data, buffer.Count);`
	`45`	`+ }`
	`46`	`+ else`
	`47`	`+ {`
	`48`	`+ ArrayPool<TElement>.Shared.Return(buffer.Data);`
`43`	`49`	`}`
`44`		`-`
`45`		`- ArrayPool<TElement>.Shared.Return(buffer.Data);`
`46`	`50`
`47`	`51`	`return result;`
`48`	`52`	`}`
Original file line number	Diff line number	Diff line change
`@@ -38,8 +38,7 @@ public void Dispose()`
`38`	`38`	`{`
`39`	`39`	`if (_sortedKeys != null)`
`40`	`40`	`{`
`41`		`- _sortedKeys.AsSpan(0, _length).Clear();`
`42`		`- ArrayPool<FormKey>.Shared.Return(_sortedKeys);`
	`41`	`+ ArrayPool<FormKey>.Shared.Return(_sortedKeys, _length);`
`43`	`42`	`}`
`44`	`43`	`}`
`45`	`44`
Original file line number	Diff line number	Diff line change
`@@ -46,15 +46,11 @@ public static async ValueTask StoreAsync(string key, OutputCacheEntry value, Has`
`46`	`46`	`{`
`47`	`47`	`if (store is IOutputCacheBufferStore bufferStore)`
`48`	`48`	`{`
`49`		`- await bufferStore.SetAsync(key, new(buffer.GetCommittedMemory()), CopyToLeasedMemory(tags, out var lease), duration, cancellationToken);`
	`49`	`+ ReadOnlyMemory<string> leasedTags = CopyToLeasedMemory(tags, out var lease);`
	`50`	`+ await bufferStore.SetAsync(key, new(buffer.GetCommittedMemory()), leasedTags, duration, cancellationToken);`
`50`	`51`	`if (lease is not null)`
`51`	`52`	`{`
`52`		`- if (tags is not null)`
`53`		`- {`
`54`		`- lease.AsSpan(0, tags.Count).Clear();`
`55`		`- }`
`56`		`-`
`57`		`- ArrayPool<string>.Shared.Return(lease);`
	`53`	`+ ArrayPool<string>.Shared.Return(lease, leasedTags.Length);`
`58`	`54`	`}`
`59`	`55`	`}`
`60`	`56`	`else`
Original file line number	Diff line number	Diff line change
`@@ -40,10 +40,12 @@ public void Dispose()`
`40`	`40`	`{`
`41`	`41`	`if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())`
`42`	`42`	`{`
`43`		`- tmp.AsSpan(0, count).Clear();`
	`43`	`+ ArrayPool<T>.Shared.Return(tmp, count);`
	`44`	`+ }`
	`45`	`+ else`
	`46`	`+ {`
	`47`	`+ ArrayPool<T>.Shared.Return(tmp);`
`44`	`48`	`}`
`45`		`-`
`46`		`- ArrayPool<T>.Shared.Return(tmp);`
`47`	`49`	`}`
`48`	`50`	`}`
`49`	`51`
`@@ -129,10 +131,12 @@ private void CheckAndResizeBuffer(int sizeHint)`
`129`	`131`	`{`
`130`	`132`	`if (RuntimeHelpers.IsReferenceOrContainsReferences<T>())`
`131`	`133`	`{`
`132`		`- oldArray.AsSpan(0, _index).Clear();`
	`134`	`+ ArrayPool<T>.Shared.Return(oldArray, _index);`
	`135`	`+ }`
	`136`	`+ else`
	`137`	`+ {`
	`138`	`+ ArrayPool<T>.Shared.Return(oldArray);`
`133`	`139`	`}`
`134`		`-`
`135`		`- ArrayPool<T>.Shared.Return(oldArray);`
`136`	`140`	`}`
`137`	`141`	`}`
`138`	`142`