scopedec

BitFaster.Caching.UnitTests/Disposable.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using FluentAssertions;
+
+namespace BitFaster.Caching.UnitTests
+{
+    public class Disposable : IDisposable
+    {
+        public bool IsDisposed { get; set; }
+
+        public void Dispose()
+        {
+            this.IsDisposed.Should().BeFalse();
+            IsDisposed = true;
+        }
+    }
+}

BitFaster.Caching.UnitTests/DisposableValueFactory.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BitFaster.Caching.UnitTests
+{
+    public class DisposableValueFactory
+    {
+        public Disposable Disposable { get; } = new Disposable();
+
+        public Scoped<Disposable> Create(int key)
+        {
+            return new Scoped<Disposable>(this.Disposable);
+        }
+    }
+}

BitFaster.Caching.UnitTests/ScopedCacheTests.cs

@@ -0,0 +1,204 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using BitFaster.Caching.Lru;
+using FluentAssertions;
+using Xunit;
+
+namespace BitFaster.Caching.UnitTests
+{
+    public class ScopedCacheTests
+    {
+        private const int capacity = 6;
+        private readonly ScopedCache<int, Disposable> cache = new (new ConcurrentLru<int, Scoped<Disposable>>(capacity));
+
+        [Fact]
+        public void WhenInnerCacheIsNullCtorThrows()
+        {
+            Action constructor = () => { var x = new ScopedCache<int, Disposable>(null); };
+
+            constructor.Should().Throw<ArgumentNullException>();
+        }
+
+        [Fact]
+        public void WhenCreatedCapacityPropertyWrapsInnerCache()
+        {
+            this.cache.Capacity.Should().Be(capacity);
+        }
+
+        [Fact]
+        public void WhenItemIsAddedCountIsCorrect()
+        {
+            this.cache.Count.Should().Be(0);
+
+            this.cache.AddOrUpdate(1, new Disposable());
+
+            this.cache.Count.Should().Be(1);
+        }
+
+        [Fact]
+        public void WhenKeyDoesNotExistAddOrUpdateAddsNewItem()
+        {
+            var d = new Disposable();
+            this.cache.AddOrUpdate(1, d);
+
+            this.cache.ScopedTryGet(1, out var lifetime).Should().BeTrue();
+            lifetime.Value.Should().Be(d);
+        }
+
+        [Fact]
+        public void WhenKeyExistsAddOrUpdateUpdatesExistingItem()
+        {
+            var d1 = new Disposable();
+            var d2 = new Disposable();
+            this.cache.AddOrUpdate(1, d1);
+            this.cache.AddOrUpdate(1, d2);
+
+            this.cache.ScopedTryGet(1, out var lifetime).Should().BeTrue();
+            lifetime.Value.Should().Be(d2);
+        }
+
+        [Fact]
+        public void WhenItemUpdatedOldValueIsAliveUntilLifetimeCompletes()
+        {
+            var d1 = new Disposable();
+            var d2 = new Disposable();
+
+            // start a lifetime on 1
+            this.cache.AddOrUpdate(1, d1);
+            this.cache.ScopedTryGet(1, out var lifetime1).Should().BeTrue();
+
+            using (lifetime1)
+            {
+                // replace 1
+                this.cache.AddOrUpdate(1, d2);
+
+                // cache reflects replacement
+                this.cache.ScopedTryGet(1, out var lifetime2).Should().BeTrue();
+                lifetime2.Value.Should().Be(d2);
+
+                d1.IsDisposed.Should().BeFalse();
+            }
+
+            d1.IsDisposed.Should().BeTrue();
+        }
+
+        [Fact]
+        public void WhenClearedItemsAreDisposed()
+        {
+            var d = new Disposable();
+            this.cache.AddOrUpdate(1, d);
+
+            this.cache.Clear();
+
+            d.IsDisposed.Should().BeTrue();
+        }
+
+        [Fact]
+        public void WhenItemExistsTryGetReturnsLifetime()
+        {
+            this.cache.AddOrUpdate(1, new Disposable());
+            this.cache.ScopedTryGet(1, out var lifetime).Should().BeTrue();
+
+            lifetime.Should().NotBeNull();
+        }
+
+        [Fact]
+        public void WhenItemDoesNotExistTryGetReturnsFalse()
+        {
+            this.cache.ScopedTryGet(1, out var lifetime).Should().BeFalse();
+        }
+
+        [Fact]
+        public void WhenScopeIsDisposedTryGetReturnsFalse()
+        {
+            var scope = new Scoped<Disposable>(new Disposable());
+
+            this.cache.ScopedGetOrAdd(1, k => scope);
+
+            scope.Dispose();
+
+            this.cache.ScopedTryGet(1, out var lifetime).Should().BeFalse();
+        }
+
+        [Fact]
+        public void WhenKeyDoesNotExistGetOrAddAddsValue()
+        {
+            this.cache.ScopedGetOrAdd(1, k => new Scoped<Disposable>(new Disposable()));
+
+            this.cache.ScopedTryGet(1, out var lifetime).Should().BeTrue();
+        }
+
+        [Fact]
+        public async Task WhenKeyDoesNotExistGetOrAddAsyncAddsValue()
+        {
+            await this.cache.ScopedGetOrAddAsync(1, k => Task.FromResult(new Scoped<Disposable>(new Disposable())));
+
+            this.cache.ScopedTryGet(1, out var lifetime).Should().BeTrue();
+        }
+
+        [Fact]
+        public void GetOrAddDisposedScopeThrows()
+        {
+            var scope = new Scoped<Disposable>(new Disposable());
+            scope.Dispose();
+
+
+            Action getOrAdd = () => { this.cache.ScopedGetOrAdd(1, k => scope); };
+
+            getOrAdd.Should().Throw<InvalidOperationException>();
+        }
+
+        [Fact]
+        public void GetOrAddAsyncDisposedScopeThrows()
+        {
+            var scope = new Scoped<Disposable>(new Disposable());
+            scope.Dispose();
+
+            Func<Task> getOrAdd = async () => { await this.cache.ScopedGetOrAddAsync(1, k => Task.FromResult(scope)); };
+
+            getOrAdd.Should().ThrowAsync<InvalidOperationException>();
+        }
+
+        [Fact]
+        public void WhenCacheContainsValuesTrim1RemovesColdestValue()
+        {
+            this.cache.AddOrUpdate(0, new Disposable());
+            this.cache.AddOrUpdate(1, new Disposable());
+            this.cache.AddOrUpdate(2, new Disposable());
+
+            this.cache.Trim(1);
+
+            this.cache.ScopedTryGet(0, out var lifetime).Should().BeFalse();
+        }
+
+        [Fact]
+        public void WhenKeyDoesNotExistTryRemoveReturnsFalse() 
+        {
+            this.cache.TryRemove(1).Should().BeFalse();
+        }
+
+        [Fact]
+        public void WhenKeyExistsTryRemoveReturnsTrue() 
+        {
+            this.cache.AddOrUpdate(1, new Disposable());
+            this.cache.TryRemove(1).Should().BeTrue();
+        }
+
+        [Fact]
+        public void WhenKeyDoesNotExistTryUpdateReturnsFalse() 
+        {
+            this.cache.TryUpdate(1, new Disposable()).Should().BeFalse();
+        }
+
+        [Fact]
+        public void WhenKeyExistsTryUpdateReturnsTrue() 
+        {
+            this.cache.AddOrUpdate(1, new Disposable());
+
+            this.cache.TryUpdate(1, new Disposable()).Should().BeTrue();
+        }
+    }
+}

BitFaster.Caching.UnitTests/ScopedTests.cs

@@ -77,26 +77,5 @@ public void WhenScopedIsCreatedFromCacheItemHasExpectedLifetime()
 
             valueFactory.Disposable.IsDisposed.Should().BeTrue();
         }
-
-        private class DisposableValueFactory
-        {
-            public Disposable Disposable { get; } = new Disposable();
-
-            public Scoped<Disposable> Create(int key)
-            {
-                return new Scoped<Disposable>(this.Disposable);
-            }
-        }
-
-        private class Disposable : IDisposable
-        {
-            public bool IsDisposed { get; set; }
-
-            public void Dispose()
-            {
-                this.IsDisposed.Should().BeFalse();
-                IsDisposed = true;
-            }
-        }
     }
 }

BitFaster.Caching/ICache.cs

@@ -38,7 +38,7 @@ public interface ICache<K, V>
         /// <param name="key">The key of the element to add.</param>
         /// <param name="valueFactory">The factory function used to generate a value for the key.</param>
         /// <returns>The value for the key. This will be either the existing value for the key if the key is already 
-        /// in the cache, or the new value if the key was not in the dictionary.</returns>
+        /// in the cache, or the new value if the key was not in the cache.</returns>
         V GetOrAdd(K key, Func<K, V> valueFactory);
 
         /// <summary>

BitFaster.Caching/IScopedCache.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BitFaster.Caching
+{
+    /// <summary>
+    /// Represents a generic cache of key/scoped IDisposable value pairs.
+    /// </summary>
+    /// <typeparam name="K">The type of keys in the cache.</typeparam>
+    /// <typeparam name="V">The type of values in the cache.</typeparam>
+    public interface IScopedCache<K, V> where V : IDisposable
+    {
+        /// <summary>
+        /// Gets the total number of items that can be stored in the cache.
+        /// </summary>
+        int Capacity { get; }
+
+        /// <summary>
+        /// Gets the number of items currently held in the cache.
+        /// </summary>
+        int Count { get; }
+
+        /// <summary>
+        /// Attempts to create a lifetime for the value associated with the specified key from the cache
+        /// </summary>
+        /// <param name="key">The key of the value to get.</param>
+        /// <param name="lifetime">When this method returns, contains a lifetime for the object from the cache that has the specified key, or the default value of the type if the operation failed.</param>
+        /// <returns>true if the key was found in the cache; otherwise, false.</returns>
+        bool ScopedTryGet(K key, out Lifetime<V> lifetime);
+
+        /// <summary>
+        /// Adds a key/scoped value pair to the cache if the key does not already exist. Returns a lifetime for either the new value, or the 
+        /// existing value if the key already exists.
+        /// </summary>
+        /// <param name="key">The key of the element to add.</param>
+        /// <param name="valueFactory">The factory function used to generate a scoped value for the key.</param>
+        /// <returns>The lifetime for the value associated with the key. The lifetime will be either reference the existing value for the key if the key is already 
+        /// in the cache, or the new value if the key was not in the cache.</returns>
+        Lifetime<V> ScopedGetOrAdd(K key, Func<K, Scoped<V>> valueFactory);
+
+        /// <summary>
+        /// Adds a key/scoped value pair to the cache if the key does not already exist. Returns a lifetime for either the new value, or the 
+        /// existing value if the key already exists.
+        /// </summary>
+        /// <param name="key">The key of the element to add.</param>
+        /// <param name="valueFactory">The factory function used to asynchronously generate a scoped value for the key.</param>
+        /// <returns>A task that represents the asynchronous ScopedGetOrAdd operation.</returns>
+        Task<Lifetime<V>> ScopedGetOrAddAsync(K key, Func<K, Task<Scoped<V>>> valueFactory);
+
+        /// <summary>
+        /// Attempts to remove the value that has the specified key.
+        /// </summary>
+        /// <param name="key">The key of the element to remove.</param>
+        /// <returns>true if the object was removed successfully; otherwise, false.</returns>
+        bool TryRemove(K key);
+
+        /// <summary>
+        /// Attempts to update the value that has the specified key.
+        /// </summary>
+        /// <param name="key">The key of the element to update.</param>
+        /// <param name="value">The new value.</param>
+        /// <returns>true if the object was updated successfully; otherwise, false.</returns>
+        bool TryUpdate(K key, V value);
+
+        /// <summary>
+        /// Adds a key/value pair to the cache if the key does not already exist, or updates a key/value pair if the 
+        /// key already exists.
+        /// </summary>
+        /// <param name="key">The key of the element to update.</param>
+        /// <param name="value">The new value.</param>
+        void AddOrUpdate(K key, V value);
+
+        /// <summary>
+        /// Removes all keys and values from the cache.
+        /// </summary>
+        void Clear();
+
+        /// <summary>
+        /// Trim the specified number of items from the cache.
+        /// </summary>
+        /// <param name="itemCount">The number of items to remove.</param>
+        void Trim(int itemCount);
+    }
+}