Added IModelServiceFactory implemenation.

Author: grokys

src/GitHub.App/Factories/ModelServiceFactory.cs

@@ -0,0 +1,64 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.Threading;
+using System.Threading.Tasks;
+using GitHub.Models;
+using GitHub.Services;
+using Microsoft.VisualStudio.Shell;
+
+namespace GitHub.Factories
+{
+    [Export(typeof(IModelServiceFactory))]
+    [PartCreationPolicy(CreationPolicy.Shared)]
+    public sealed class ModelServiceFactory : IModelServiceFactory, IDisposable
+    {
+        readonly IApiClientFactory apiClientFactory;
+        readonly IHostCacheFactory hostCacheFactory;
+        readonly IAvatarProvider avatarProvider;
+        readonly Dictionary<IConnection, ModelService> cache = new Dictionary<IConnection, ModelService>();
+        readonly SemaphoreSlim cacheLock = new SemaphoreSlim(1);
+
+        [ImportingConstructor]
+        public ModelServiceFactory(
+            IApiClientFactory apiClientFactory,
+            IHostCacheFactory hostCacheFactory,
+            IAvatarProvider avatarProvider)
+        {
+            this.apiClientFactory = apiClientFactory;
+            this.hostCacheFactory = hostCacheFactory;
+            this.avatarProvider = avatarProvider;
+        }
+
+        public async Task<IModelService> CreateAsync(IConnection connection)
+        {
+            ModelService result;
+
+            await cacheLock.WaitAsync();
+
+            try
+            {
+                if (!cache.TryGetValue(connection, out result))
+                {
+                    result = new ModelService(
+                        await apiClientFactory.Create(connection.HostAddress),
+                        await hostCacheFactory.Create(connection.HostAddress),
+                        avatarProvider);
+                }
+            }
+            finally
+            {
+                cacheLock.Release();
+            }
+
+            return result;
+        }
+
+        public IModelService CreateBlocking(IConnection connection)
+        {
+            return ThreadHelper.JoinableTaskFactory.Run(() => CreateAsync(connection));
+        }
+
+        public void Dispose() => cacheLock.Dispose();
+    }
+}

src/GitHub.App/GitHub.App.csproj

@@ -127,6 +127,7 @@
     <Reference Include="WindowsBase" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Factories\ModelServiceFactory.cs" />
     <Compile Include="Models\IssueCommentModel.cs" />
     <Compile Include="Models\PullRequestReviewCommentModel.cs" />
     <Compile Include="Models\PullRequestDetailArgument.cs" />

src/UnitTests/UnitTests.csproj

@@ -227,8 +227,6 @@
     <Compile Include="GitHub.App\Models\ModelServiceTests.cs" />
     <Compile Include="GitHub.App\Controllers\UIControllerTests.cs" />
     <Compile Include="GitHub.App\Models\PullRequestModelTests.cs" />
-    <Compile Include="GitHub.App\Models\RepositoryHostsTests.cs" />
-    <Compile Include="GitHub.App\Models\RepositoryHostTests.cs" />
     <Compile Include="GitHub.App\Models\RepositoryModelTests.cs" />
     <Compile Include="GitHub.App\Services\AvatarProviderTests.cs" />
     <Compile Include="GitHub.App\Services\GitClientTests.cs" />