From f4a3a0e76b1f1b3dc279b771f8ea7bf632943528 Mon Sep 17 00:00:00 2001
From: Anton Firszov <antonfir@gmail.com>
Date: Fri, 27 Aug 2021 16:56:57 +0200
Subject: [PATCH] fix ManagedBufferBase pinning behavior

---
 .../Allocators/Internals/ManagedBufferBase.cs |  4 ++--
 .../ArrayPoolMemoryAllocatorTests.cs          | 17 ++++++++++++++++
 .../SimpleGcMemoryAllocatorTests.cs           | 20 ++++++++++++++++++-
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/ImageSharp/Memory/Allocators/Internals/ManagedBufferBase.cs b/src/ImageSharp/Memory/Allocators/Internals/ManagedBufferBase.cs
index 3f54e335e..f88c3a5f4 100644
--- a/src/ImageSharp/Memory/Allocators/Internals/ManagedBufferBase.cs
+++ b/src/ImageSharp/Memory/Allocators/Internals/ManagedBufferBase.cs
@@ -24,7 +24,7 @@ namespace SixLabors.ImageSharp.Memory.Internals
             }
 
             void* ptr = (void*)this.pinHandle.AddrOfPinnedObject();
-            return new MemoryHandle(ptr, this.pinHandle);
+            return new MemoryHandle(ptr, this.pinHandle, this);
         }
 
         /// <inheritdoc />
@@ -42,4 +42,4 @@ namespace SixLabors.ImageSharp.Memory.Internals
         /// <returns>The pinnable <see cref="object"/>.</returns>
         protected abstract object GetPinnableObject();
     }
-}
\ No newline at end of file
+}
diff --git a/tests/ImageSharp.Tests/Memory/Allocators/ArrayPoolMemoryAllocatorTests.cs b/tests/ImageSharp.Tests/Memory/Allocators/ArrayPoolMemoryAllocatorTests.cs
index 7620d63de..dd53b0b56 100644
--- a/tests/ImageSharp.Tests/Memory/Allocators/ArrayPoolMemoryAllocatorTests.cs
+++ b/tests/ImageSharp.Tests/Memory/Allocators/ArrayPoolMemoryAllocatorTests.cs
@@ -114,6 +114,23 @@ namespace SixLabors.ImageSharp.Tests.Memory.Allocators
             }
         }
 
+        [Fact]
+        public unsafe void Allocate_MemoryIsPinnableMultipleTimes()
+        {
+            ArrayPoolMemoryAllocator allocator = this.LocalFixture.MemoryAllocator;
+            using IMemoryOwner<byte> memoryOwner = allocator.Allocate<byte>(100);
+
+            using (MemoryHandle pin = memoryOwner.Memory.Pin())
+            {
+                Assert.NotEqual(IntPtr.Zero, (IntPtr)pin.Pointer);
+            }
+
+            using (MemoryHandle pin = memoryOwner.Memory.Pin())
+            {
+                Assert.NotEqual(IntPtr.Zero, (IntPtr)pin.Pointer);
+            }
+        }
+
         [Theory]
         [InlineData(false)]
         [InlineData(true)]
diff --git a/tests/ImageSharp.Tests/Memory/Allocators/SimpleGcMemoryAllocatorTests.cs b/tests/ImageSharp.Tests/Memory/Allocators/SimpleGcMemoryAllocatorTests.cs
index 8e7b30567..0e1f99725 100644
--- a/tests/ImageSharp.Tests/Memory/Allocators/SimpleGcMemoryAllocatorTests.cs
+++ b/tests/ImageSharp.Tests/Memory/Allocators/SimpleGcMemoryAllocatorTests.cs
@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System;
+using System.Buffers;
 using System.Runtime.InteropServices;
 using SixLabors.ImageSharp.Memory;
 using Xunit;
@@ -36,9 +37,26 @@ namespace SixLabors.ImageSharp.Tests.Memory.Allocators
             Assert.Equal("length", ex.ParamName);
         }
 
+        [Fact]
+        public unsafe void Allocate_MemoryIsPinnableMultipleTimes()
+        {
+            SimpleGcMemoryAllocator allocator = this.MemoryAllocator;
+            using IMemoryOwner<byte> memoryOwner = allocator.Allocate<byte>(100);
+
+            using (MemoryHandle pin = memoryOwner.Memory.Pin())
+            {
+                Assert.NotEqual(IntPtr.Zero, (IntPtr)pin.Pointer);
+            }
+
+            using (MemoryHandle pin = memoryOwner.Memory.Pin())
+            {
+                Assert.NotEqual(IntPtr.Zero, (IntPtr)pin.Pointer);
+            }
+        }
+
         [StructLayout(LayoutKind.Explicit, Size = 512)]
         private struct BigStruct
         {
         }
     }
-}
\ No newline at end of file
+}