Add size based eviction to MemoryCache

Caching.sln

@@ -1,6 +1,6 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.26228.9
+VisualStudioVersion = 15.0.26621.2
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.Extensions.Caching.Memory", "src\Microsoft.Extensions.Caching.Memory\Microsoft.Extensions.Caching.Memory.csproj", "{966D16D8-5D4E-4433-9DA7-F53EE44B7EE7}"
 EndProject
@@ -243,4 +243,7 @@ Global
 		{17E332EB-D18D-4BF5-BCA5-989E36C78B79} = {459E1593-2C11-42CB-AD17-F7597E69E5D2}
 		{ADF83AC7-3776-4E62-A222-C6979C32DD2D} = {9E78AA8E-7870-46DE-A49F-856F5A0A9166}
 	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {30FC4CB3-9789-4A49-939D-03398DBE03E0}
+	EndGlobalSection
 EndGlobal

src/Microsoft.Extensions.Caching.Abstractions/CacheEntryExtensions.cs

@@ -133,6 +133,24 @@ public static ICacheEntry SetValue(
             return entry;
         }
 
+        /// <summary>
+        /// Sets the size of the cache entry value.
+        /// </summary>
+        /// <param name="entry"></param>
+        /// <param name="size"></param>
+        public static ICacheEntry SetSize(
+            this ICacheEntry entry,
+            long size)
+        {
+            if (size < 0)
+            {
+                throw new ArgumentOutOfRangeException(nameof(size), size, $"{nameof(size)} must be non-negative.");
+            }
+
+            entry.Size = size;
+            return entry;
+        }
+
         /// <summary>
         /// Applies the values of an existing <see cref="MemoryCacheEntryOptions"/> to the entry.
         /// </summary>
@@ -149,6 +167,7 @@ public static ICacheEntry SetOptions(this ICacheEntry entry, MemoryCacheEntryOpt
             entry.AbsoluteExpirationRelativeToNow = options.AbsoluteExpirationRelativeToNow;
             entry.SlidingExpiration = options.SlidingExpiration;
             entry.Priority = options.Priority;
+            entry.Size = options.Size;
 
             foreach (var expirationToken in options.ExpirationTokens)
             {

src/Microsoft.Extensions.Caching.Abstractions/EvictionReason.cs

@@ -28,7 +28,7 @@ public enum EvictionReason
         TokenExpired,
 
         /// <summary>
-        /// GC, overflow
+        /// Overflow
         /// </summary>
         Capacity,
     }

src/Microsoft.Extensions.Caching.Abstractions/ICacheEntry.cs

@@ -26,7 +26,7 @@ public interface ICacheEntry : IDisposable
         /// Gets or sets an absolute expiration date for the cache entry.
         /// </summary>
         DateTimeOffset? AbsoluteExpiration { get; set; }
-        
+
         /// <summary>
         /// Gets or sets an absolute expiration time, relative to now.
         /// </summary>
@@ -50,9 +50,13 @@ public interface ICacheEntry : IDisposable
 
         /// <summary>
         /// Gets or sets the priority for keeping the cache entry in the cache during a
-        /// memory pressure triggered cleanup. The default is <see cref="CacheItemPriority.Normal"/>.
+        ///  cleanup. The default is <see cref="CacheItemPriority.Normal"/>.
         /// </summary>
         CacheItemPriority Priority { get; set; }
 
+        /// <summary>
+        /// Gets or set the size of the cache entry value.
+        /// </summary>
+        long? Size { get; set; }
     }
 }

src/Microsoft.Extensions.Caching.Abstractions/MemoryCacheEntryExtensions.cs

@@ -21,6 +21,24 @@ public static MemoryCacheEntryOptions SetPriority(
             return options;
         }
 
+        /// <summary>
+        /// Sets the size of the cache entry value.
+        /// </summary>
+        /// <param name="options"></param>
+        /// <param name="size"></param>
+        public static MemoryCacheEntryOptions SetSize(
+            this MemoryCacheEntryOptions options,
+            long size)
+        {
+            if (size < 0)
+            {
+                throw new ArgumentOutOfRangeException(nameof(size), size, $"{nameof(size)} must be non-negative.");
+            }
+
+            options.Size = size;
+            return options;
+        }
+
         /// <summary>
         /// Expire the cache entry if the given <see cref="IChangeToken"/> expires.
         /// </summary>

src/Microsoft.Extensions.Caching.Abstractions/MemoryCacheEntryOptions.cs

@@ -12,6 +12,7 @@ public class MemoryCacheEntryOptions
         private DateTimeOffset? _absoluteExpiration;
         private TimeSpan? _absoluteExpirationRelativeToNow;
         private TimeSpan? _slidingExpiration;
+        private long? _size;
 
         /// <summary>
         /// Gets or sets an absolute expiration date for the cache entry.
@@ -90,5 +91,22 @@ public TimeSpan? SlidingExpiration
         /// memory pressure triggered cleanup. The default is <see cref="CacheItemPriority.Normal"/>.
         /// </summary>
         public CacheItemPriority Priority { get; set; } = CacheItemPriority.Normal;
+
+        /// <summary>
+        /// Gets or sets the size of the cache entry value.
+        /// </summary>
+        public long? Size
+        {
+            get => _size;
+            set
+            {
+                if (value < 0)
+                {
+                    throw new ArgumentOutOfRangeException(nameof(value), value, $"{nameof(value)} must be non-negative.");
+                }
+
+                _size = value;
+            }
+        }
     }
 }

src/Microsoft.Extensions.Caching.Abstractions/breakingchanges.netcore.json

@@ -58,5 +58,15 @@
     "TypeId": "public static class Microsoft.Extensions.Caching.Distributed.DistributedCacheExtensions",
     "MemberId": "public static System.Threading.Tasks.Task<System.String> GetStringAsync(this Microsoft.Extensions.Caching.Distributed.IDistributedCache cache, System.String key)",
     "Kind": "Removal"
+  },
+  {
+    "TypeId": "public interface Microsoft.Extensions.Caching.Memory.ICacheEntry : System.IDisposable",
+    "MemberId": "System.Nullable<System.Int64> get_Size()",
+    "Kind": "Addition"
+  },
+  {
+    "TypeId": "public interface Microsoft.Extensions.Caching.Memory.ICacheEntry : System.IDisposable",
+    "MemberId": "System.Void set_Size(System.Nullable<System.Int64> value)",
+    "Kind": "Addition"
   }
 ]

src/Microsoft.Extensions.Caching.Memory/CacheEntry.cs

@@ -23,6 +23,7 @@ internal class CacheEntry : ICacheEntry
         internal DateTimeOffset? _absoluteExpiration;
         internal TimeSpan? _absoluteExpirationRelativeToNow;
         private TimeSpan? _slidingExpiration;
+        private long? _size;
         private IDisposable _scope;
 
         internal readonly object _lock = new object();
@@ -153,6 +154,23 @@ public IList<PostEvictionCallbackRegistration> PostEvictionCallbacks
         /// </summary>
         public CacheItemPriority Priority { get; set; } = CacheItemPriority.Normal;
 
+        /// <summary>
+        /// Gets or sets the size of the cache entry value.
+        /// </summary>
+        public long? Size
+        {
+            get => _size;
+            set
+            {
+                if (value < 0)
+                {
+                    throw new ArgumentOutOfRangeException(nameof(value), value, $"{nameof(value)} must be non-negative.");
+                }
+
+                _size = value;
+            }
+        }
+
         public object Key { get; private set; }
 
         public object Value { get; set; }