1 files changed, 52 insertions, 0 deletions
diff --git a/src/Core/Impl/Features/FeatureCookie.cs b/src/Core/Impl/Features/FeatureCookie.cs
new file mode 100644
index 0000000..7d884f8
--- /dev/null
+++ b/src/Core/Impl/Features/FeatureCookie.cs
@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Microsoft.VisualStudio.Utilities.Features.Implementation
+{
+    internal class FeatureCookie : IFeatureCookie
+    {
+        public string FeatureName { get; private set; }
+
+        public event EventHandler<FeatureChangedEventArgs> StateChanged;
+
+        public bool IsEnabled
+        {
+            get => this.featureIsEnabled;
+            private set
+            {
+                if (this.featureIsEnabled == value)
+                    return;
+
+                this.featureIsEnabled = value;
+                StateChanged?.Invoke(this, new FeatureChangedEventArgs(FeatureName, value));
+            }
+        }
+
+
+        private bool featureIsEnabled;
+        private IEnumerable<string> aliases;
+        private FeatureService service;
+
+        internal FeatureCookie(string featureName, IEnumerable<string> aliases, FeatureService service)
+        {
+            FeatureName = featureName;
+            this.aliases = aliases;
+            this.service = service;
+
+            IsEnabled = service.IsEnabled(FeatureName);
+            this.service.StateUpdated += OnStateUpdated;
+        }
+
+        /// <summary>
+        /// Recalculates <see cref="IsEnabled" /> after pertinent feature or its base feature has updated.
+        /// </summary>
+        private void OnStateUpdated(object sender, FeatureUpdatedEventArgs args)
+        {
+            if (aliases.Contains(args.FeatureName))
+            {
+                IsEnabled = this.service.IsEnabled(this.FeatureName);
+            }
+        }
+    }
+}