Add additional target .netstandard2.0 +semver: minor

Author: calledude

AsyncMemoryCache/AsyncMemoryCache.cs

@@ -30,7 +30,12 @@ public sealed class AsyncMemoryCache<TKey, TValue> : IAsyncDisposable, IAsyncMem
 
 	public AsyncMemoryCache(IAsyncMemoryCacheConfiguration<TKey, TValue> configuration, ILogger<AsyncMemoryCache<TKey, TValue>>? logger = null)
 	{
+#if NET8_0_OR_GREATER
 		ArgumentNullException.ThrowIfNull(configuration);
+#else
+		if (configuration is null)
+			throw new ArgumentNullException(nameof(configuration));
+#endif
 
 		_configuration = configuration;
 		_cache = configuration.CacheBackingStore;

AsyncMemoryCache/AsyncMemoryCache.csproj

@@ -1,9 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
 	<PropertyGroup>
-		<TargetFramework>net8.0</TargetFramework>
+		<TargetFrameworks>net8.0;netstandard2.0</TargetFrameworks>
 		<Nullable>enable</Nullable>
 
+		<LangVersion>latest</LangVersion>
+
 		<EnableNETAnalyzers>true</EnableNETAnalyzers>
 		<AnalysisLevel>preview</AnalysisLevel>
 
@@ -34,10 +36,17 @@
 		</Description>
 	</PropertyGroup>
 
+	<ItemGroup Condition="$(TargetFramework) == 'netstandard2.0'">
+		<PackageReference Include="PolySharp" Version="1.14.1">
+			<PrivateAssets>all</PrivateAssets>
+			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+		</PackageReference>
+	</ItemGroup>
+	
 	<ItemGroup>
 		<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="8.0.0" />
 		<PackageReference Include="Nito.AsyncEx.Coordination" Version="5.1.2" />
-
+		
 		<PackageReference Include="Roslynator.Analyzers" Version="4.10.0">
 			<PrivateAssets>all</PrivateAssets>
 			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

AsyncMemoryCache/CacheEntityReference.cs

@@ -14,13 +14,20 @@ public sealed class CacheEntityReference<TKey, TValue> : IDisposable
 
 	public CacheEntityReference(CacheEntity<TKey, TValue> cacheEntity)
 	{
+#if NET8_0_OR_GREATER
 		ArgumentNullException.ThrowIfNull(cacheEntity);
+#else
+		if (cacheEntity is null)
+			throw new ArgumentNullException(nameof(cacheEntity));
+#endif
 
 		CacheEntity = cacheEntity;
 		_ = Interlocked.Increment(ref cacheEntity.References);
 	}
 
+#if NET8_0_OR_GREATER
 	[ExcludeFromCodeCoverage(Justification = "Finalizers are unreliable in tests")]
+#endif
 	~CacheEntityReference()
 	{
 		Dispose();

AsyncMemoryCache/EvictionBehaviors/DefaultEvictionBehavior.cs

@@ -8,22 +8,34 @@ namespace AsyncMemoryCache.EvictionBehaviors;
 
 public sealed class DefaultEvictionBehavior : IEvictionBehavior
 {
-	private readonly PeriodicTimer _timer;
 	private readonly CancellationTokenSource _cts;
+	private readonly TimeSpan _interval;
+#if NET8_0_OR_GREATER
+	private readonly PeriodicTimer _timer;
 	private Task? _workerTask;
 
 	public DefaultEvictionBehavior(TimeProvider? timeProvider = default, TimeSpan? evictionCheckInterval = default)
 	{
-		var interval = evictionCheckInterval ?? TimeSpan.FromSeconds(30);
-		_timer = new(interval, timeProvider ?? TimeProvider.System);
+		_interval = evictionCheckInterval ?? TimeSpan.FromSeconds(30);
+		_timer = new(_interval, timeProvider ?? TimeProvider.System);
+		_cts = new();
+	}
+#else
+	private Timer? _timer;
+
+	public DefaultEvictionBehavior(TimeSpan? evictionCheckInterval = default)
+	{
 		_cts = new();
+		_interval = evictionCheckInterval ?? TimeSpan.FromSeconds(30);
 	}
+#endif
 
 	public void Start<TKey, TValue>(IAsyncMemoryCacheConfiguration<TKey, TValue> configuration, ILogger<AsyncMemoryCache<TKey, TValue>> logger)
 		where TKey : notnull
 		where TValue : IAsyncDisposable
 	{
-		logger.LogTrace("Starting evictionbehavior - expiry check interval {Interval}.", _timer.Period);
+		logger.LogTrace("Starting evictionbehavior - expiry check interval {Interval}.", _interval);
+#if NET8_0_OR_GREATER
 		_workerTask = Task.Factory.StartNew(async () =>
 		{
 			try
@@ -37,10 +49,14 @@ public void Start<TKey, TValue>(IAsyncMemoryCacheConfiguration<TKey, TValue> con
 			{
 				logger.LogTrace("CancellationToken was cancelled.");
 			}
+
+			logger.LogTrace("Stopping behavior.");
 		}, _cts.Token, TaskCreationOptions.LongRunning, TaskScheduler.Default)
 		.Unwrap();
 
-		logger.LogTrace("Stopping behavior.");
+#else
+		_timer = new(async _ => await CheckExpiredItems(configuration, logger).ConfigureAwait(false), null, 0, (uint)_interval.TotalMilliseconds);
+#endif
 	}
 
 	private static async Task CheckExpiredItems<TKey, TValue>(IAsyncMemoryCacheConfiguration<TKey, TValue> configuration, ILogger<AsyncMemoryCache<TKey, TValue>> logger)
@@ -83,6 +99,7 @@ private static async Task CheckExpiredItems<TKey, TValue>(IAsyncMemoryCacheConfi
 		logger.LogTrace("Done checking expired items. Evicted {EvictedItemsCount} items.", expiredItems.Count);
 	}
 
+#if NET8_0_OR_GREATER
 	public async ValueTask DisposeAsync()
 	{
 		_timer.Dispose();
@@ -95,4 +112,14 @@ public async ValueTask DisposeAsync()
 
 		_cts.Dispose();
 	}
+#else
+	public ValueTask DisposeAsync()
+	{
+		_timer?.Dispose();
+		_cts.Cancel();
+		_cts.Dispose();
+
+		return default;
+	}
+#endif
 }

AsyncMemoryCache/EvictionBehaviors/EvictionBehavior.cs

@@ -5,7 +5,11 @@ namespace AsyncMemoryCache.EvictionBehaviors;
 
 public static class EvictionBehavior
 {
+#if NET8_0_OR_GREATER
 	public static readonly IEvictionBehavior Default = new DefaultEvictionBehavior(TimeProvider.System);
+#else
+	public static readonly IEvictionBehavior Default = new DefaultEvictionBehavior();
+#endif
 	public static readonly IEvictionBehavior Disabled = new NoOpEvictionBehavior();
 }
 

AsyncMemoryCache/EvictionBehaviors/NoOpEvictionBehavior.cs

@@ -5,7 +5,9 @@
 
 namespace AsyncMemoryCache.EvictionBehaviors;
 
+#if NET8_0_OR_GREATER
 [ExcludeFromCodeCoverage(Justification = "Nothing to test")]
+#endif
 internal sealed class NoOpEvictionBehavior : IEvictionBehavior
 {
 	public void Start<TKey, TValue>(IAsyncMemoryCacheConfiguration<TKey, TValue> configuration, ILogger<AsyncMemoryCache<TKey, TValue>>? logger)
@@ -14,5 +16,9 @@ public void Start<TKey, TValue>(IAsyncMemoryCacheConfiguration<TKey, TValue> con
 	{
 	}
 
+#if NET8_0_OR_GREATER
 	public ValueTask DisposeAsync() => ValueTask.CompletedTask;
+#else
+	public ValueTask DisposeAsync() => default;
+#endif
 }

AsyncMemoryCache/ExpirationStrategy/AbsoluteExpirationStrategy.cs

@@ -15,7 +15,9 @@ internal AbsoluteExpirationStrategy(DateTimeOffset expiryDate)
 	public bool IsExpired()
 		=> DateTimeOffset.UtcNow > AbsoluteExpiration;
 
+#if NET8_0_OR_GREATER
 	[ExcludeFromCodeCoverage(Justification = "Empty implementation")]
+#endif
 	public void CacheEntityAccessed()
 	{
 	}