Covering ArrayPoolMemoryManager and it's buffer. Took hours, but worth it!

src/ImageSharp/Memory/IBuffer{T}.cs

@@ -1,3 +1,6 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
 using System;
 
 namespace SixLabors.ImageSharp.Memory

src/ImageSharp/Memory/IManagedByteBuffer.cs

@@ -1,3 +1,6 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
 namespace SixLabors.ImageSharp.Memory
 {
     /// <summary>

src/ImageSharp/Memory/MemoryManager.cs

@@ -1,8 +1,5 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
 
 namespace SixLabors.ImageSharp.Memory
 {

tests/ImageSharp.Tests/Memory/ArrayPoolMemoryManagerTests.cs

@@ -1,3 +1,6 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
 // ReSharper disable InconsistentNaming
 namespace SixLabors.ImageSharp.Tests.Memory
 {
@@ -16,39 +19,31 @@ namespace SixLabors.ImageSharp.Tests.Memory
         private MemoryManager MemoryManager { get; } = new ArrayPoolMemoryManager(MaxPooledBufferSizeInBytes);
         
         /// <summary>
-        /// Rent 'n' buffers -> return all -> re-rent, verify if there is at least one in common.
+        /// Rent a buffer -> return it -> re-rent -> verify if it's span points to the previous location
         /// </summary>
-        private bool CheckIsPooled<T>(int size)
+        private bool CheckIsRentingPooledBuffer<T>(int length)
             where T : struct
         {
-            IBuffer<T> buf1 = this.MemoryManager.Allocate<T>(size);
-            IBuffer<T> buf2 = this.MemoryManager.Allocate<T>(size);
-            IBuffer<T> buf3 = this.MemoryManager.Allocate<T>(size);
-
-            ref T buf1FirstPrev = ref buf1.DangerousGetPinnableReference();
-            ref T buf2FirstPrev = ref buf2.DangerousGetPinnableReference();
-            ref T buf3FirstPrev = ref buf3.DangerousGetPinnableReference();
-
-            buf1.Dispose();
-            buf2.Dispose();
-            buf3.Dispose();
-
-            buf1 = this.MemoryManager.Allocate<T>(size);
-            buf2 = this.MemoryManager.Allocate<T>(size);
-            buf3 = this.MemoryManager.Allocate<T>(size);
-
-            bool same1 = Unsafe.AreSame(ref buf1FirstPrev, ref buf1.DangerousGetPinnableReference());
-            bool same2 = Unsafe.AreSame(ref buf2FirstPrev, ref buf2.DangerousGetPinnableReference());
-            bool same3 = Unsafe.AreSame(ref buf3FirstPrev, ref buf3.DangerousGetPinnableReference());
-
-            buf1.Dispose();
-            buf2.Dispose();
-            buf3.Dispose();
+            IBuffer<T> buffer = this.MemoryManager.Allocate<T>(length);
+            ref T ptrToPrevPosition0 = ref buffer.DangerousGetPinnableReference();
+            buffer.Dispose();
+            
+            buffer = this.MemoryManager.Allocate<T>(length);
+            bool sameBuffers = Unsafe.AreSame(ref ptrToPrevPosition0, ref buffer.DangerousGetPinnableReference());
+            buffer.Dispose();
+
+            return sameBuffers;
+        }
 
-            return same1 || same2 || same3;
+        public class BufferTests : BufferTestSuite
+        {
+            public BufferTests()
+                : base(new ArrayPoolMemoryManager(MaxPooledBufferSizeInBytes))
+            {
+            }
         }
 
-        [StructLayout(LayoutKind.Explicit, Size = MaxPooledBufferSizeInBytes / 4)]
+        [StructLayout(LayoutKind.Explicit, Size = MaxPooledBufferSizeInBytes / 5)]
         struct LargeStruct
         {
         }
@@ -59,7 +54,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
         [InlineData(MaxPooledBufferSizeInBytes - 1)]
         public void SmallBuffersArePooled_OfByte(int size)
         {
-            Assert.True(this.CheckIsPooled<byte>(size));
+            Assert.True(this.CheckIsRentingPooledBuffer<byte>(size));
         }
 
 
@@ -68,7 +63,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
         [InlineData(MaxPooledBufferSizeInBytes + 1)]
         public void LargeBuffersAreNotPooled_OfByte(int size)
         {
-            Assert.False(this.CheckIsPooled<byte>(size));
+            Assert.False(this.CheckIsRentingPooledBuffer<byte>(size));
         }
 
         [Fact]
@@ -76,7 +71,7 @@ namespace SixLabors.ImageSharp.Tests.Memory
         {
             int count = MaxPooledBufferSizeInBytes / sizeof(LargeStruct) - 1;
 
-            Assert.True(this.CheckIsPooled<LargeStruct>(count));
+            Assert.True(this.CheckIsRentingPooledBuffer<LargeStruct>(count));
         }
 
         [Fact]
@@ -84,7 +79,24 @@ namespace SixLabors.ImageSharp.Tests.Memory
         {
             int count = MaxPooledBufferSizeInBytes / sizeof(LargeStruct) + 1;
 
-            Assert.False(this.CheckIsPooled<LargeStruct>(count));
+            Assert.False(this.CheckIsRentingPooledBuffer<LargeStruct>(count));
+        }
+
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void CleaningRequests_AreControlledByAllocationParameter_Clean(bool clean)
+        {
+            using (IBuffer<int> firstAlloc = this.MemoryManager.Allocate<int>(42))
+            {
+                firstAlloc.Span.Fill(666);
+            }
+
+            using (IBuffer<int> secondAlloc = this.MemoryManager.Allocate<int>(42, clean))
+            {
+                int expected = clean ? 0 : 666;
+                Assert.Equal(expected, secondAlloc.Span[0]);
+            }
         }
     }
 }

tests/ImageSharp.Tests/Memory/BufferTestSuite.cs

@@ -0,0 +1,285 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Runtime.CompilerServices;
+using SixLabors.ImageSharp.Memory;
+using Xunit;
+// ReSharper disable InconsistentNaming
+
+namespace SixLabors.ImageSharp.Tests.Memory
+{
+    
+
+    /// <summary>
+    /// Inherit this class to test an <see cref="IBuffer{T}"/> implementation (provided by <see cref="MemoryManager"/>).
+    /// </summary>
+    public abstract class BufferTestSuite
+    {
+        protected BufferTestSuite(MemoryManager memoryManager)
+        {
+            this.MemoryManager = memoryManager;
+        }
+
+        protected MemoryManager MemoryManager { get; }
+
+        public struct CustomStruct : IEquatable<CustomStruct>
+        {
+            public long A;
+
+            public byte B;
+
+            public float C;
+
+            public CustomStruct(long a, byte b, float c)
+            {
+                this.A = a;
+                this.B = b;
+                this.C = c;
+            }
+
+            public bool Equals(CustomStruct other)
+            {
+                return this.A == other.A && this.B == other.B && this.C.Equals(other.C);
+            }
+
+            public override bool Equals(object obj)
+            {
+                if (ReferenceEquals(null, obj)) return false;
+                return obj is CustomStruct && this.Equals((CustomStruct)obj);
+            }
+
+            public override int GetHashCode()
+            {
+                unchecked
+                {
+                    int hashCode = this.A.GetHashCode();
+                    hashCode = (hashCode * 397) ^ this.B.GetHashCode();
+                    hashCode = (hashCode * 397) ^ this.C.GetHashCode();
+                    return hashCode;
+                }
+            }
+        }
+
+        public static readonly TheoryData<int> LenthValues = new TheoryData<int> { 0, 1, 7, 1023, 1024 };
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void HasCorrectLength_byte(int desiredLength)
+        {
+            this.TestHasCorrectLength<byte>(desiredLength);
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void HasCorrectLength_float(int desiredLength)
+        {
+            this.TestHasCorrectLength<float>(desiredLength);
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void HasCorrectLength_CustomStruct(int desiredLength)
+        {
+            this.TestHasCorrectLength<CustomStruct>(desiredLength);
+        }
+
+        private void TestHasCorrectLength<T>(int desiredLength)
+            where T : struct
+        {
+            using (IBuffer<T> buffer = this.MemoryManager.Allocate<T>(desiredLength))
+            {
+                Assert.Equal(desiredLength, buffer.Span.Length);
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void CanAllocateCleanBuffer_byte(int desiredLength)
+        {
+            this.TestCanAllocateCleanBuffer<byte>(desiredLength, false);
+            this.TestCanAllocateCleanBuffer<byte>(desiredLength, true);
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void CanAllocateCleanBuffer_double(int desiredLength)
+        {
+            this.TestCanAllocateCleanBuffer<double>(desiredLength);
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void CanAllocateCleanBuffer_CustomStruct(int desiredLength)
+        {
+            this.TestCanAllocateCleanBuffer<CustomStruct>(desiredLength);
+        }
+
+        private IBuffer<T> Allocate<T>(int desiredLength, bool clean, bool managedByteBuffer)
+            where T : struct
+        {
+            if (managedByteBuffer)
+            {
+                if (!(this.MemoryManager.AllocateManagedByteBuffer(desiredLength, clean) is IBuffer<T> buffer))
+                {
+                    throw new InvalidOperationException("typeof(T) != typeof(byte)");
+                }
+
+                return buffer;
+            }
+
+            return this.MemoryManager.Allocate<T>(desiredLength, clean);
+        }
+
+        private void TestCanAllocateCleanBuffer<T>(int desiredLength, bool testManagedByteBuffer = false)
+            where T : struct, IEquatable<T>
+        {
+            ReadOnlySpan<T> expected = new T[desiredLength];
+
+            for (int i = 0; i < 10; i++)
+            {
+                using (IBuffer<T> buffer = this.Allocate<T>(desiredLength, true, testManagedByteBuffer))
+                {
+                    Assert.True(buffer.Span.SequenceEqual(expected));
+                }
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void SpanPropertyIsAlwaysTheSame_int(int desiredLength)
+        {
+            this.TestSpanPropertyIsAlwaysTheSame<int>(desiredLength);
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void SpanPropertyIsAlwaysTheSame_byte(int desiredLength)
+        {
+            this.TestSpanPropertyIsAlwaysTheSame<byte>(desiredLength, false);
+            this.TestSpanPropertyIsAlwaysTheSame<byte>(desiredLength, true);
+        }
+
+        private void TestSpanPropertyIsAlwaysTheSame<T>(int desiredLength, bool testManagedByteBuffer = false)
+            where T : struct
+        {
+            using (IBuffer<T> buffer = this.Allocate<T>(desiredLength, false, testManagedByteBuffer))
+            {
+                ref T a = ref buffer.Span.DangerousGetPinnableReference();
+                ref T b = ref buffer.Span.DangerousGetPinnableReference();
+                ref T c = ref buffer.Span.DangerousGetPinnableReference();
+
+                Assert.True(Unsafe.AreSame(ref a, ref b));
+                Assert.True(Unsafe.AreSame(ref b, ref c));
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void WriteAndReadElements_float(int desiredLength)
+        {
+            this.TestWriteAndReadElements<float>(desiredLength, x => x * 1.2f);
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void WriteAndReadElements_byte(int desiredLength)
+        {
+            this.TestWriteAndReadElements<byte>(desiredLength, x => (byte)(x+1), false);
+            this.TestWriteAndReadElements<byte>(desiredLength, x => (byte)(x + 1), true);
+        }
+
+        private void TestWriteAndReadElements<T>(int desiredLength, Func<int, T> getExpectedValue, bool testManagedByteBuffer = false)
+            where T : struct
+        {
+            using (IBuffer<T> buffer = this.Allocate<T>(desiredLength, false, testManagedByteBuffer))
+            {
+                T[] expectedVals = new T[buffer.Length()];
+
+                for (int i = 0; i < buffer.Length(); i++)
+                {
+                    Span<T> span = buffer.Span;
+                    expectedVals[i] = getExpectedValue(i);
+                    span[i] = expectedVals[i];
+                }
+
+                for (int i = 0; i < buffer.Length(); i++)
+                {
+                    Span<T> span = buffer.Span;
+                    Assert.Equal(expectedVals[i], span[i]);
+                }
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void IndexingSpan_WhenOutOfRange_Throws_byte(int desiredLength)
+        {
+            this.TestIndexOutOfRangeShouldThrow<byte>(desiredLength, false);
+            this.TestIndexOutOfRangeShouldThrow<byte>(desiredLength, true);
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void IndexingSpan_WhenOutOfRange_Throws_long(int desiredLength)
+        {
+            this.TestIndexOutOfRangeShouldThrow<long>(desiredLength);
+        }
+
+        [Theory]
+        [MemberData(nameof(LenthValues))]
+        public void IndexingSpan_WhenOutOfRange_Throws_CustomStruct(int desiredLength)
+        {
+            this.TestIndexOutOfRangeShouldThrow<CustomStruct>(desiredLength);
+        }
+
+        private T TestIndexOutOfRangeShouldThrow<T>(int desiredLength, bool testManagedByteBuffer = false)
+            where T : struct, IEquatable<T>
+        {
+            var dummy = default(T);
+
+            using (IBuffer<T> buffer = this.Allocate<T>(desiredLength, false, testManagedByteBuffer))
+            {
+                Assert.ThrowsAny<Exception>(
+                    () =>
+                        {
+                            Span<T> span = buffer.Span;
+                            dummy = span[desiredLength];
+                        });
+
+                Assert.ThrowsAny<Exception>(
+                    () =>
+                        {
+                            Span<T> span = buffer.Span;
+                            dummy = span[desiredLength + 1];
+                        });
+
+                Assert.ThrowsAny<Exception>(
+                    () =>
+                        {
+                            Span<T> span = buffer.Span;
+                            dummy = span[desiredLength + 42];
+                        });
+            }
+
+            return dummy;
+        }
+
+        [Theory]
+        [InlineData(1)]
+        [InlineData(7)]
+        [InlineData(1024)]
+        [InlineData(6666)]
+        public void ManagedByteBuffer_ArrayIsCorrect(int desiredLength)
+        {
+            using (IManagedByteBuffer buffer = this.MemoryManager.AllocateManagedByteBuffer(desiredLength))
+            {
+                ref byte array0 = ref buffer.Array[0];
+                ref byte span0 = ref buffer.DangerousGetPinnableReference();
+
+                Assert.True(Unsafe.AreSame(ref span0, ref array0));
+                Assert.True(buffer.Array.Length >= buffer.Span.Length);
+            }
+        }
+    }
+}

tests/ImageSharp.Tests/Memory/SimpleManagedMemoryManagerTests.cs

@@ -0,0 +1,15 @@
+namespace SixLabors.ImageSharp.Tests.Memory
+{
+    using SixLabors.ImageSharp.Memory;
+
+    public class SimpleManagedMemoryManagerTests
+    {
+        public class BufferTests : BufferTestSuite
+        {
+            public BufferTests()
+                : base(new SimpleManagedMemoryManager())
+            {
+            }
+        }
+    }
+}