Add System.Threading.Lock (#10)

PolyShim.Tests/Net90/LockTests.cs

@@ -0,0 +1,93 @@
+using System.Threading;
+using FluentAssertions;
+using Xunit;
+
+namespace PolyShim.Tests.Net90;
+
+public class LockTests
+{
+    [Fact]
+    public void Enter_Test()
+    {
+        // Arrange
+        var syncRoot = new Lock();
+
+        // Act & assert
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+        syncRoot.Enter();
+        syncRoot.IsHeldByCurrentThread.Should().BeTrue();
+    }
+
+    [Fact]
+    public void TryEnter_Test()
+    {
+        // Arrange
+        var syncRoot = new Lock();
+
+        // Act & assert
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+        syncRoot.TryEnter().Should().BeTrue();
+        syncRoot.IsHeldByCurrentThread.Should().BeTrue();
+    }
+
+    [Fact]
+    public void TryEnter_Timeout_Test()
+    {
+        // Arrange
+        var syncRoot = new Lock();
+
+        // Act & assert
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+        syncRoot.TryEnter(100).Should().BeTrue();
+        syncRoot.IsHeldByCurrentThread.Should().BeTrue();
+    }
+
+    [Fact]
+    public void Exit_Test()
+    {
+        // Arrange
+        var syncRoot = new Lock();
+
+        // Act & assert
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+        syncRoot.Enter();
+        syncRoot.IsHeldByCurrentThread.Should().BeTrue();
+        syncRoot.Exit();
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+    }
+
+    [Fact]
+    public void EnterScope_Test()
+    {
+        // Arrange
+        var syncRoot = new Lock();
+
+        // Act & assert
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+        using (syncRoot.EnterScope())
+        {
+            syncRoot.IsHeldByCurrentThread.Should().BeTrue();
+        }
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+    }
+
+    [Fact]
+    public void EnterScope_Layered_Test()
+    {
+        // Arrange
+        var syncRoot = new Lock();
+
+        // Act & assert
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+        using (syncRoot.EnterScope())
+        {
+            syncRoot.IsHeldByCurrentThread.Should().BeTrue();
+            using (syncRoot.EnterScope())
+            {
+                syncRoot.IsHeldByCurrentThread.Should().BeTrue();
+            }
+            syncRoot.IsHeldByCurrentThread.Should().BeTrue();
+        }
+        syncRoot.IsHeldByCurrentThread.Should().BeFalse();
+    }
+}

PolyShim/Net90/Lock.cs

@@ -0,0 +1,42 @@
+#if (NETCOREAPP && !NET9_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+#pragma warning disable CS9216
+// ReSharper disable RedundantUsingDirective
+// ReSharper disable CheckNamespace
+// ReSharper disable InconsistentNaming
+// ReSharper disable PartialTypeWithSinglePart
+
+namespace System.Threading;
+
+internal partial class Lock
+{
+#if (NETCOREAPP) || (NETFRAMEWORK && NET45_OR_GREATER) || (NETSTANDARD)
+    public bool IsHeldByCurrentThread => Monitor.IsEntered(this);
+#endif
+
+    public void Enter() => Monitor.Enter(this);
+
+    public bool TryEnter() => Monitor.TryEnter(this);
+
+    public bool TryEnter(TimeSpan timeout) => Monitor.TryEnter(this, timeout);
+
+    public bool TryEnter(int millisecondsTimeout) =>
+        TryEnter(TimeSpan.FromMilliseconds(millisecondsTimeout));
+
+    public void Exit() => Monitor.Exit(this);
+
+    public Scope EnterScope()
+    {
+        Enter();
+        return new Scope(this);
+    }
+}
+
+internal partial class Lock
+{
+    public readonly ref struct Scope(Lock owner)
+    {
+        public void Dispose() => owner.Exit();
+    }
+}
+#endif