Introduce ObjectPool and use it for ResilienceContext pooling

src/Polly.Core.Benchmarks/README.md

@@ -12,44 +12,44 @@ LaunchCount=2  WarmupCount=10
 
 ## PIPELINES
 
-|             Method | Components |        Mean |     Error |    StdDev | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
-|------------------- |----------- |------------:|----------:|----------:|------:|--------:|-------:|----------:|------------:|
-| ExecutePipeline_V7 |          1 |    71.29 ns |  1.309 ns |  1.959 ns |  1.00 |    0.00 | 0.0362 |     304 B |        1.00 |
-| ExecutePipeline_V8 |          1 |    92.93 ns |  1.398 ns |  2.049 ns |  1.30 |    0.05 | 0.0181 |     152 B |        0.50 |
-|                    |            |             |           |           |       |         |        |           |             |
-| ExecutePipeline_V7 |          2 |   164.39 ns |  5.294 ns |  7.592 ns |  1.00 |    0.00 | 0.0658 |     552 B |        1.00 |
-| ExecutePipeline_V8 |          2 |   126.74 ns |  1.198 ns |  1.755 ns |  0.77 |    0.04 | 0.0181 |     152 B |        0.28 |
-|                    |            |             |           |           |       |         |        |           |             |
-| ExecutePipeline_V7 |          5 |   540.07 ns | 16.941 ns | 24.832 ns |  1.00 |    0.00 | 0.1545 |    1296 B |        1.00 |
-| ExecutePipeline_V8 |          5 |   257.13 ns |  2.748 ns |  4.114 ns |  0.48 |    0.03 | 0.0181 |     152 B |        0.12 |
-|                    |            |             |           |           |       |         |        |           |             |
-| ExecutePipeline_V7 |         10 | 1,111.72 ns | 16.405 ns | 23.527 ns |  1.00 |    0.00 | 0.3014 |    2536 B |        1.00 |
-| ExecutePipeline_V8 |         10 |   467.93 ns |  6.546 ns |  9.388 ns |  0.42 |    0.01 | 0.0181 |     152 B |        0.06 |
+|             Method | Components |        Mean |     Error |     StdDev |      Median | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
+|------------------- |----------- |------------:|----------:|-----------:|------------:|------:|--------:|-------:|----------:|------------:|
+| ExecutePipeline_V7 |          1 |    74.78 ns |  1.555 ns |   2.279 ns |    75.63 ns |  1.00 |    0.00 | 0.0362 |     304 B |        1.00 |
+| ExecutePipeline_V8 |          1 |    85.69 ns |  0.500 ns |   0.732 ns |    85.36 ns |  1.15 |    0.04 |      - |         - |        0.00 |
+|                    |            |             |           |            |             |       |         |        |           |             |
+| ExecutePipeline_V7 |          2 |   165.37 ns |  1.157 ns |   1.732 ns |   165.59 ns |  1.00 |    0.00 | 0.0658 |     552 B |        1.00 |
+| ExecutePipeline_V8 |          2 |   119.10 ns |  0.653 ns |   0.915 ns |   119.63 ns |  0.72 |    0.01 |      - |         - |        0.00 |
+|                    |            |             |           |            |             |       |         |        |           |             |
+| ExecutePipeline_V7 |          5 |   533.97 ns |  7.327 ns |  10.967 ns |   536.79 ns |  1.00 |    0.00 | 0.1545 |    1296 B |        1.00 |
+| ExecutePipeline_V8 |          5 |   227.69 ns |  1.236 ns |   1.812 ns |   227.72 ns |  0.43 |    0.01 |      - |         - |        0.00 |
+|                    |            |             |           |            |             |       |         |        |           |             |
+| ExecutePipeline_V7 |         10 | 1,191.41 ns | 35.512 ns |  53.152 ns | 1,192.79 ns |  1.00 |    0.00 | 0.3014 |    2536 B |        1.00 |
+| ExecutePipeline_V8 |         10 |   557.95 ns | 76.434 ns | 112.036 ns |   505.58 ns |  0.47 |    0.09 |      - |         - |        0.00 |
 
 ## TIMEOUT
 
-|            Method |     Mean |   Error |   StdDev | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
-|------------------ |---------:|--------:|---------:|------:|--------:|-------:|----------:|------------:|
-| ExecuteTimeout_V7 | 287.1 ns | 9.20 ns | 12.59 ns |  1.00 |    0.00 | 0.0868 |     728 B |        1.00 |
-| ExecuteTimeout_V8 | 272.9 ns | 3.16 ns |  4.54 ns |  0.95 |    0.04 | 0.0439 |     368 B |        0.51 |
+|            Method |     Mean |   Error |  StdDev | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
+|------------------ |---------:|--------:|--------:|------:|--------:|-------:|----------:|------------:|
+| ExecuteTimeout_V7 | 281.5 ns | 5.76 ns | 8.08 ns |  1.00 |    0.00 | 0.0868 |     728 B |        1.00 |
+| ExecuteTimeout_V8 | 268.9 ns | 3.86 ns | 5.53 ns |  0.96 |    0.04 | 0.0257 |     216 B |        0.30 |
 
 ## RETRY
 
 |          Method |     Mean |   Error |  StdDev | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
 |---------------- |---------:|--------:|--------:|------:|--------:|-------:|----------:|------------:|
-| ExecuteRetry_V7 | 162.5 ns | 2.33 ns | 3.34 ns |  1.00 |    0.00 | 0.0687 |     576 B |        1.00 |
-| ExecuteRetry_V8 | 152.3 ns | 1.31 ns | 1.93 ns |  0.94 |    0.02 | 0.0181 |     152 B |        0.26 |
+| ExecuteRetry_V7 | 169.8 ns | 4.98 ns | 6.98 ns |  1.00 |    0.00 | 0.0687 |     576 B |        1.00 |
+| ExecuteRetry_V8 | 144.9 ns | 2.35 ns | 3.52 ns |  0.85 |    0.04 |      - |         - |        0.00 |
 
 ## RATE LIMITER
 
-|                Method |     Mean |   Error |  StdDev | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
-|---------------------- |---------:|--------:|--------:|------:|--------:|-------:|----------:|------------:|
-| ExecuteRateLimiter_V7 | 173.8 ns | 2.33 ns | 3.48 ns |  1.00 |    0.00 | 0.0448 |     376 B |        1.00 |
-| ExecuteRateLimiter_V8 | 207.9 ns | 2.06 ns | 2.89 ns |  1.19 |    0.03 | 0.0229 |     192 B |        0.51 |
+|                Method |     Mean |    Error |   StdDev | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
+|---------------------- |---------:|---------:|---------:|------:|--------:|-------:|----------:|------------:|
+| ExecuteRateLimiter_V7 | 190.8 ns | 10.01 ns | 14.98 ns |  1.00 |    0.00 | 0.0448 |     376 B |        1.00 |
+| ExecuteRateLimiter_V8 | 199.6 ns |  2.54 ns |  3.64 ns |  1.05 |    0.09 | 0.0048 |      40 B |        0.11 |
 
 ## STRATEGY PIPELINE (TIMEOUT + RETRY + TIMEOUT + RATE LIMITER)
 
-|                     Method |     Mean |     Error |    StdDev |   Median | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
-|--------------------------- |---------:|----------:|----------:|---------:|------:|--------:|-------:|----------:|------------:|
-| ExecuteStrategyPipeline_V7 | 1.207 us | 0.0201 us | 0.0295 us | 1.202 us |  1.00 |    0.00 | 0.2861 |    2400 B |        1.00 |
-| ExecuteStrategyPipeline_V8 | 1.117 us | 0.0297 us | 0.0407 us | 1.118 us |  0.93 |    0.05 | 0.0935 |     792 B |        0.33 |
+|                     Method |     Mean |     Error |    StdDev | Ratio | RatioSD |   Gen0 | Allocated | Alloc Ratio |
+|--------------------------- |---------:|----------:|----------:|------:|--------:|-------:|----------:|------------:|
+| ExecuteStrategyPipeline_V7 | 1.321 us | 0.0355 us | 0.0520 us |  1.00 |    0.00 | 0.2861 |    2400 B |        1.00 |
+| ExecuteStrategyPipeline_V8 | 1.126 us | 0.0193 us | 0.0283 us |  0.85 |    0.03 | 0.0763 |     640 B |        0.27 |

src/Polly.Core.Tests/ExecutionRejectedExceptionTests.cs

@@ -1,11 +1,11 @@
-namespace Polly.Core.Tests.Timeout;
+namespace Polly.Core.Tests;
 
 public class ExecutionRejectedExceptionTests
 {
     [Fact]
     public void Ctor_Ok()
     {
-        new CustomException().Message.Should().Be("Exception of type 'Polly.Core.Tests.Timeout.ExecutionRejectedExceptionTests+CustomException' was thrown.");
+        new CustomException().Message.Should().Be("Exception of type 'Polly.Core.Tests.ExecutionRejectedExceptionTests+CustomException' was thrown.");
         new CustomException("Dummy").Message.Should().Be("Dummy");
     }
 

src/Polly.Core.Tests/Utils/BinarySerializationUtil.cs → src/Polly.Core.Tests/Helpers/BinarySerializationUtil.cs

@@ -2,7 +2,7 @@
 
 using System;
 
-namespace Polly.Core.Tests.Utils;
+namespace Polly.Core.Tests.Helpers;
 
 /// <summary>
 /// Utility that serializes and deserializes the exceptions using the binary formatter.

src/Polly.Core.Tests/Utils/FakeTimeProvider.cs → src/Polly.Core.Tests/Helpers/FakeTimeProvider.cs

@@ -1,7 +1,7 @@
 using Moq;
 using Polly.Utils;
 
-namespace Polly.Core.Tests.Utils;
+namespace Polly.Core.Tests.Helpers;
 
 internal class FakeTimeProvider : Mock<TimeProvider>
 {

src/Polly.Core.Tests/Utils/TestArguments.cs → src/Polly.Core.Tests/Helpers/TestArguments.cs

@@ -1,6 +1,6 @@
 using Polly.Strategy;
 
-namespace Polly.Core.Tests.Utils;
+namespace Polly.Core.Tests.Helpers;
 
 public class TestArguments : IResilienceArguments
 {

src/Polly.Core.Tests/Utils/TestResilienceStrategy.cs → src/Polly.Core.Tests/Helpers/TestResilienceStrategy.cs

@@ -1,4 +1,4 @@
-namespace Polly.Core.Tests.Utils;
+namespace Polly.Core.Tests.Helpers;
 
 public class TestResilienceStrategy : ResilienceStrategy
 {

src/Polly.Core.Tests/Utils/TestUtils.cs → src/Polly.Core.Tests/Helpers/TestUtils.cs

@@ -1,4 +1,4 @@
-namespace Polly.Core.Tests.Utils;
+namespace Polly.Core.Tests.Helpers;
 
 #pragma warning disable CA1031 // Do not catch general exception types
 

src/Polly.Core.Tests/Polly.Core.Tests.csproj

@@ -16,6 +16,6 @@
   </ItemGroup>
 
   <ItemGroup>
-    <Using Include="Polly.Core.Tests.Utils" />
+    <Using Include="Polly.Core.Tests.Helpers" />
   </ItemGroup>
 </Project>

src/Polly.Core.Tests/Registry/StrategyId.cs

@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-
 namespace Polly.Core.Tests.Registry;
 
 public record StrategyId(Type Type, string BuilderName, string InstanceName = "")

src/Polly.Core.Tests/ResilienceContextTests.cs

@@ -16,6 +16,16 @@ public void Get_EnsureDefaults()
         AssertDefaults(context);
     }
 
+    [Fact]
+    public void Get_EnsurePooled()
+    {
+        var context = ResilienceContext.Get();
+
+        ResilienceContext.Return(context);
+
+        ResilienceContext.Get().Should().BeSameAs(context);
+    }
+
     [Fact]
     public void Return_Null_Throws()
     {

src/Polly.Core.Tests/Retry/RetryDelayGeneratorTests.cs

@@ -1,8 +1,5 @@
-using System;
-using System.Threading.Tasks;
 using Polly.Retry;
 using Polly.Strategy;
-using Xunit;
 
 namespace Polly.Core.Tests.Retry;
 

src/Polly.Core.Tests/Retry/RetryHelperTests.cs

@@ -1,4 +1,3 @@
-using System;
 using Polly.Retry;
 
 namespace Polly.Core.Tests.Retry;

src/Polly.Core.Tests/Retry/RetryResilienceStrategyBuilderExtensionsTests.cs

@@ -1,7 +1,6 @@
 using System.ComponentModel.DataAnnotations;
 using Polly.Builder;
 using Polly.Retry;
-using Xunit;
 
 namespace Polly.Core.Tests.Retry;
 

src/Polly.Core.Tests/Strategy/OutcomeEventTests.cs

@@ -1,5 +1,3 @@
-using System;
-using System.Threading.Tasks;
 using Polly.Strategy;
 
 namespace Polly.Core.Tests.Strategy;

src/Polly.Core.Tests/Strategy/OutcomeGeneratorTests.cs

@@ -1,5 +1,3 @@
-using System;
-using System.Threading.Tasks;
 using Polly.Strategy;
 
 namespace Polly.Core.Tests.Strategy;

src/Polly.Core.Tests/Strategy/OutcomePredicateTests.cs

@@ -1,5 +1,3 @@
-using System;
-using System.Threading.Tasks;
 using Polly.Strategy;
 
 namespace Polly.Core.Tests.Strategy;

src/Polly.Core.Tests/Strategy/OutcomeTests.cs

@@ -1,4 +1,3 @@
-using System;
 using Polly.Strategy;
 
 namespace Polly.Core.Tests.Strategy;

src/Polly.Core.Tests/Strategy/SimpleEventTests.cs

@@ -1,14 +1,14 @@
 using Polly.Strategy;
 
-namespace Polly.Core.Tests.Timeout;
+namespace Polly.Core.Tests.Strategy;
 
 public class SimpleEventTests
 {
     [Fact]
     public async Task Add_EnsureOrdering()
     {
         var ev = new DummyEvent();
-        List<int> raisedEvents = new List<int>();
+        var raisedEvents = new List<int>();
 
         ev.Add(() => raisedEvents.Add(1));
         ev.Add(args => raisedEvents.Add(2));
@@ -41,7 +41,7 @@ public async Task CreateHandler_Ok(int count)
         var ev = new DummyEvent();
         var events = new List<int>();
 
-        for (int i = 0; i < count; i++)
+        for (var i = 0; i < count; i++)
         {
             ev.Add(() => events.Add(i));
         }

src/Polly.Core.Tests/Timeout/TimeoutAttributeTests.cs

@@ -1,4 +1,3 @@
-using System.ComponentModel.DataAnnotations;
 using Polly.Timeout;
 
 namespace Polly.Core.Tests.Timeout;

src/Polly.Core.Tests/Timeout/TimeoutStrategyOptionsTests.cs

@@ -1,7 +1,6 @@
 using System.ComponentModel.DataAnnotations;
 using Polly.Timeout;
 using Polly.Utils;
-using Xunit;
 
 namespace Polly.Core.Tests.Timeout;
 

src/Polly.Core.Tests/Timeout/TimeoutUtilTests.cs

@@ -1,6 +1,4 @@
-using System;
 using Polly.Timeout;
-using Xunit;
 
 namespace Polly.Core.Tests.Timeout;
 public class TimeoutUtilTests

src/Polly.Core.Tests/Utils/ObjectPoolTests.cs

@@ -0,0 +1,111 @@
+using Polly.Utils;
+
+namespace Polly.Core.Tests.Utils;
+
+public class ObjectPoolTests
+{
+    [Fact]
+    public void GetAnd_ReturnObject_SameInstance()
+    {
+        // Arrange
+        var pool = new ObjectPool<object>(() => new object(), _ => true);
+
+        var obj1 = pool.Get();
+        pool.Return(obj1);
+
+        // Act
+        var obj2 = pool.Get();
+
+        // Assert
+        Assert.Same(obj1, obj2);
+    }
+
+    [Fact]
+    public void MaxCapacity_Ok()
+    {
+        ObjectPool<object>.MaxCapacity.Should().Be((Environment.ProcessorCount * 2) - 1);
+    }
+
+    [Fact]
+    public void MaxCapacity_Respected()
+    {
+        // Arrange
+        var pool = new ObjectPool<object>(() => new object(), _ => true);
+        var items1 = GetStoreReturn(pool);
+
+        // Act
+        var items2 = GetStoreReturn(pool);
+
+        // Assert
+        items1.Should().BeEquivalentTo(items2);
+    }
+
+    [Fact]
+    public void MaxCapacityOverflow_Respected()
+    {
+        // Arrange
+        var count = ObjectPool<object>.MaxCapacity + 10;
+        var pool = new ObjectPool<object>(() => new object(), _ => true);
+        var items1 = GetStoreReturn(pool, count);
+
+        // Act
+        var items2 = GetStoreReturn(pool, count);
+
+        // Assert
+        items1.Last().Should().NotBeSameAs(items2.Last());
+    }
+
+    [Fact]
+    public void CreatedByPolicy()
+    {
+        // Arrange
+        var policy = new ListPolicy();
+        var pool = new ObjectPool<List<int>>(ListPolicy.Create, ListPolicy.Return);
+
+        // Act
+        var list = pool.Get();
+
+        // Assert
+        Assert.Equal(17, list.Capacity);
+    }
+
+    [Fact]
+    public void Return_RejectedByPolicy()
+    {
+        // Arrange
+        var policy = new ListPolicy();
+        var pool = new ObjectPool<List<int>>(ListPolicy.Create, ListPolicy.Return);
+        var list1 = pool.Get();
+        list1.Capacity = 20;
+
+        // Act
+        pool.Return(list1);
+        var list2 = pool.Get();
+
+        // Assert
+        Assert.NotSame(list1, list2);
+    }
+
+    private static List<object> GetStoreReturn(ObjectPool<object> pool, int? count = null)
+    {
+        var items = new List<object>();
+        for (int i = 0; i < (count ?? ObjectPool<object>.MaxCapacity); i++)
+        {
+            items.Add(pool.Get());
+        }
+
+        foreach (var item in items)
+        {
+            pool.Return(item);
+        }
+
+        return items;
+    }
+
+    private class ListPolicy
+    {
+        public static List<int> Create() => new(17);
+
+        public static bool Return(List<int> obj) => obj.Capacity == 17;
+    }
+}

src/Polly.Core.Tests/Utils/TimeSpanAttributeTests.cs

@@ -1,4 +1,3 @@
-using System;
 using System.ComponentModel.DataAnnotations;
 
 namespace Polly.Core.Tests.Utils;

src/Polly.Core.Tests/Utils/ValidationContextExtensions.cs → src/Polly.Core.Tests/Utils/ValidationContextExtensionsTests.cs

@@ -2,7 +2,7 @@
 
 namespace Polly.Core.Tests.Utils;
 
-public class ValidationContextExtensions
+public class ValidationContextExtensionsTests
 {
     [Fact]
     public void GetMemberName_Ok()