Persist the low-memory-mode option to the registry

src/VisualStudio/Core/Impl/Options/AbstractLocalUserRegistryOptionSerializer.cs

@@ -0,0 +1,96 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
+using Microsoft.CodeAnalysis.Options;
+using Microsoft.CodeAnalysis.Options.Providers;
+using Microsoft.VisualStudio.Shell;
+using Microsoft.VisualStudio.Shell.Interop;
+using Microsoft.Win32;
+
+namespace Microsoft.VisualStudio.LanguageServices.Implementation.Options
+{
+    internal abstract class AbstractLocalUserRegistryOptionSerializer : ForegroundThreadAffinitizedObject, IOptionSerializer
+    {
+        /// <summary>
+        /// An object to gate access to <see cref="_registryKey"/>.
+        /// </summary>
+        private readonly object _gate = new object();
+        private readonly RegistryKey _registryKey;
+
+        protected abstract string GetCollectionPathForOption(OptionKey key);
+
+        public AbstractLocalUserRegistryOptionSerializer(IServiceProvider serviceProvider)
+            : base(assertIsForeground: true) // The VSRegistry.RegistryRoot call requires being on the UI thread or else it will marshal and risk deadlock
+        {
+            this._registryKey = VSRegistry.RegistryRoot(serviceProvider, __VsLocalRegistryType.RegType_UserSettings, writable: true);
+        }
+
+        bool IOptionSerializer.TryFetch(OptionKey optionKey, out object value)
+        {
+            var collectionPath = GetCollectionPathForOption(optionKey);
+            if (collectionPath == null)
+            {
+                value = null;
+                return false;
+            }
+
+            lock (_gate)
+            {
+                using (var subKey = this._registryKey.OpenSubKey(collectionPath))
+                {
+                    if (subKey == null)
+                    {
+                        value = null;
+                        return false;
+                    }
+
+                    // Options that are of type bool have to be serialized as integers
+                    if (optionKey.Option.Type == typeof(bool))
+                    {
+                        value = subKey.GetValue(optionKey.Option.Name, defaultValue: (bool)optionKey.Option.DefaultValue ? 1 : 0).Equals(1);
+                        return true;
+                    }
+                    else
+                    {
+                        // Otherwise we can just store normally
+                        value = subKey.GetValue(optionKey.Option.Name, defaultValue: optionKey.Option.DefaultValue);
+                        return true;
+                    }
+                }
+            }
+        }
+
+        bool IOptionSerializer.TryPersist(OptionKey optionKey, object value)
+        {
+            if (this._registryKey == null)
+            {
+                throw new InvalidOperationException();
+            }
+
+            var collectionPath = GetCollectionPathForOption(optionKey);
+            if (collectionPath == null)
+            {
+                return false;
+            }
+
+            lock (_gate)
+            {
+                using (var subKey = this._registryKey.CreateSubKey(collectionPath))
+                {
+                    // Options that are of type bool have to be serialized as integers
+                    if (optionKey.Option.Type == typeof(bool))
+                    {
+                        subKey.SetValue(optionKey.Option.Name, (bool)value ? 1 : 0, RegistryValueKind.DWord);
+                        return true;
+                    }
+                    else
+                    {
+                        subKey.SetValue(optionKey.Option.Name, value);
+                        return true;
+                    }
+                }
+            }
+        }
+    }
+}

src/VisualStudio/Core/Impl/Options/InternalOptionSerializer.cs

@@ -21,70 +21,46 @@ namespace Microsoft.VisualStudio.LanguageServices.Implementation.Options
         CacheOptions.FeatureName,
         InternalDiagnosticsOptions.OptionName,
         InternalSolutionCrawlerOptions.OptionName), Shared]
-    internal class InternalOptionSerializer : AbstractSettingStoreOptionSerializer
+    internal class InternalOptionSerializer : AbstractLocalUserRegistryOptionSerializer
     {
         [ImportingConstructor]
         public InternalOptionSerializer(SVsServiceProvider serviceProvider)
             : base(serviceProvider)
         {
         }
 
-        protected override Tuple<string, string> GetCollectionPathAndPropertyNameForOption(IOption key, string languageName)
+        protected override string GetCollectionPathForOption(OptionKey key)
         {
-            if (key.Feature == EditorComponentOnOffOptions.OptionName)
+            if (key.Option.Feature == EditorComponentOnOffOptions.OptionName)
             {
-                return Tuple.Create(@"Roslyn\Internal\OnOff\Components", key.Name);
+                return @"Roslyn\Internal\OnOff\Components";
             }
-            else if (key.Feature == InternalFeatureOnOffOptions.OptionName)
+            else if (key.Option.Feature == InternalFeatureOnOffOptions.OptionName)
             {
-                return Tuple.Create(@"Roslyn\Internal\OnOff\Features", key.Name);
+                return @"Roslyn\Internal\OnOff\Features";
             }
-            else if (key.Feature == PerformanceFunctionIdOptionsProvider.Name)
+            else if (key.Option.Feature == PerformanceFunctionIdOptionsProvider.Name)
             {
-                return Tuple.Create(@"Roslyn\Internal\Performance\FunctionId", key.Name);
+                return @"Roslyn\Internal\Performance\FunctionId";
             }
-            else if (key.Feature == LoggerOptions.FeatureName)
+            else if (key.Option.Feature == LoggerOptions.FeatureName)
             {
-                return Tuple.Create(@"Roslyn\Internal\Performance\Logger", key.Name);
+                return @"Roslyn\Internal\Performance\Logger";
             }
-            else if (key.Feature == InternalDiagnosticsOptions.OptionName)
+            else if (key.Option.Feature == InternalDiagnosticsOptions.OptionName)
             {
-                return Tuple.Create(@"Roslyn\Internal\Diagnostics", key.Name);
+                return @"Roslyn\Internal\Diagnostics";
             }
-            else if (key.Feature == InternalSolutionCrawlerOptions.OptionName)
+            else if (key.Option.Feature == InternalSolutionCrawlerOptions.OptionName)
             {
-                return Tuple.Create(@"Roslyn\Internal\SolutionCrawler", key.Name);
+                return @"Roslyn\Internal\SolutionCrawler";
             }
-            else if (key.Feature == CacheOptions.FeatureName)
+            else if (key.Option.Feature == CacheOptions.FeatureName)
             {
-                return Tuple.Create(@"Roslyn\Internal\Performance\Cache", key.Name);
+                return @"Roslyn\Internal\Performance\Cache";
             }
 
             throw ExceptionUtilities.Unreachable;
         }
-
-        public override bool TryFetch(OptionKey optionKey, out object value)
-        {
-            switch (optionKey.Option.Feature)
-            {
-                case CacheOptions.FeatureName:
-                case InternalSolutionCrawlerOptions.OptionName:
-                    return TryFetch(optionKey, (r, k, o) => r.GetValue(k, defaultValue: o.DefaultValue), out value);
-            }
-
-            return base.TryFetch(optionKey, out value);
-        }
-
-        public override bool TryPersist(OptionKey optionKey, object value)
-        {
-            switch (optionKey.Option.Feature)
-            {
-                case CacheOptions.FeatureName:
-                case InternalSolutionCrawlerOptions.OptionName:
-                    return TryPersist(optionKey, value, (r, k, o, v) => r.SetValue(k, v, o.Type == typeof(int) ? RegistryValueKind.DWord : RegistryValueKind.QWord));
-            }
-
-            return base.TryPersist(optionKey, value);
-        }
     }
 }

src/VisualStudio/Core/Impl/ServicesVisualStudioImpl.csproj

@@ -244,7 +244,7 @@
     <Compile Include="Options\AbstractOptionPageControl.cs" />
     <Compile Include="Options\AbstractRadioButtonViewModel.cs" />
     <Compile Include="Options\AbstractSettingsManagerOptionSerializer.cs" />
-    <Compile Include="Options\AbstractSettingStoreOptionSerializer.cs" />
+    <Compile Include="Options\AbstractLocalUserRegistryOptionSerializer.cs" />
     <Compile Include="Options\CheckBoxViewModel.cs" />
     <Compile Include="Options\HeaderItemViewModel.cs" />
     <Compile Include="Options\OptionBinding.cs" />