Factor out UsageTrackingCommand

Author: jcansdale

src/GitHub.App/Commands/UsageTrackingCommand.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Windows.Input;
+using System.Linq.Expressions;
+using GitHub.Models;
+using GitHub.Services;
+using GitHub.Extensions;
+
+namespace GitHub.Commands
+{
+    /// <summary>
+    /// A proxy <see cref="ICommand"/> that increments a usage counter after executing the command.
+    /// </summary>
+    public class UsageTrackingCommand : ICommand
+    {
+        readonly ICommand command;
+        readonly Lazy<IUsageTracker> usageTracker;
+        readonly Expression<Func<UsageModel.MeasuresModel, int>> counter;
+
+        /// <summary>
+        /// The usage tracker and counter to increment after the target command is executed.
+        /// </summary>
+        /// <param name="usageTracker">The usage tracker.</param>
+        /// <param name="counter">The counter to increment.</param>
+        /// <param name="command">The target command.</param>
+        public UsageTrackingCommand(
+            Lazy<IUsageTracker> usageTracker, Expression<Func<UsageModel.MeasuresModel, int>> counter,
+            ICommand command)
+        {
+            this.command = command;
+            this.usageTracker = usageTracker;
+            this.counter = counter;
+        }
+
+        public event EventHandler CanExecuteChanged
+        {
+            add { command.CanExecuteChanged += value; }
+            remove { command.CanExecuteChanged -= value; }
+        }
+
+        public bool CanExecute(object parameter)
+        {
+            return command.CanExecute(parameter);
+        }
+
+        public void Execute(object parameter)
+        {
+            command.Execute(parameter);
+            usageTracker.Value.IncrementCounter(counter).Forget();
+        }
+    }
+}

src/GitHub.App/GitHub.App.csproj

@@ -205,6 +205,7 @@
     <Reference Include="WindowsBase" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Commands\UsageTrackingCommand.cs" />
     <Compile Include="Factories\ViewViewModelFactory.cs" />
     <Compile Include="Factories\ModelServiceFactory.cs" />
     <Compile Include="Models\IssueCommentModel.cs" />

src/GitHub.InlineReviews/Services/PullRequestStatusBarManager.cs

@@ -5,14 +5,12 @@
 using System.Windows.Controls.Primitives;
 using System.ComponentModel.Composition;
 using System.Reactive.Linq;
-using System.Linq.Expressions;
 using GitHub.Commands;
 using GitHub.InlineReviews.Views;
 using GitHub.InlineReviews.ViewModels;
 using GitHub.Services;
 using GitHub.Models;
 using GitHub.Logging;
-using GitHub.Extensions;
 using Serilog;
 using ReactiveUI;
 
@@ -45,10 +43,10 @@ public PullRequestStatusBarManager(
             Lazy<IPullRequestSessionManager> pullRequestSessionManager,
             Lazy<ITeamExplorerContext> teamExplorerContext)
         {
-            this.openPullRequestsCommand = new UsageTrackingCommand(openPullRequestsCommand,
-                usageTracker, x => x.NumberOfStatusBarOpenPullRequestList);
-            this.showCurrentPullRequestCommand = new UsageTrackingCommand(showCurrentPullRequestCommand,
-                usageTracker, x => x.NumberOfShowCurrentPullRequest);
+            this.openPullRequestsCommand = new UsageTrackingCommand(usageTracker,
+                x => x.NumberOfStatusBarOpenPullRequestList, openPullRequestsCommand);
+            this.showCurrentPullRequestCommand = new UsageTrackingCommand(usageTracker,
+                x => x.NumberOfShowCurrentPullRequest, showCurrentPullRequestCommand);
 
             this.pullRequestSessionManager = pullRequestSessionManager;
             this.teamExplorerContext = teamExplorerContext;
@@ -143,37 +141,5 @@ StatusBar FindSccStatusBar(Window mainWindow)
             var contentControl = mainWindow?.Template?.FindName(StatusBarPartName, mainWindow) as ContentControl;
             return contentControl?.Content as StatusBar;
         }
-
-        class UsageTrackingCommand : ICommand
-        {
-            readonly ICommand command;
-            readonly Lazy<IUsageTracker> usageTracker;
-            readonly Expression<Func<UsageModel.MeasuresModel, int>> counter;
-
-            internal UsageTrackingCommand(ICommand command, Lazy<IUsageTracker> usageTracker,
-                Expression<Func<UsageModel.MeasuresModel, int>> counter)
-            {
-                this.command = command;
-                this.usageTracker = usageTracker;
-                this.counter = counter;
-            }
-
-            public event EventHandler CanExecuteChanged
-            {
-                add { command.CanExecuteChanged += value; }
-                remove { command.CanExecuteChanged -= value; }
-            }
-
-            public bool CanExecute(object parameter)
-            {
-                return command.CanExecute(parameter);
-            }
-
-            public void Execute(object parameter)
-            {
-                command.Execute(parameter);
-                usageTracker.Value.IncrementCounter(counter).Forget();
-            }
-        }
     }
 }