Changes to be able to quit the application via exit inside a CLI prompt. (#746)

* Changes to be able to quit the application via exit inside a CLI prompt.

src/cascadia/TerminalApp/App.cpp

@@ -827,12 +827,11 @@ namespace winrt::TerminalApp::implementation
     // - tabViewItem: the TabViewItem in the TabView that is being removed.
     void App::_RemoveTabViewItem(const IInspectable& tabViewItem)
     {
-        // TODO: GitHub:627: Need a better story for what should happen when the last tab is closed.
-        if (_tabs.size() <= 1)
+        // To close the window here, we need to close the hosting window.
+        if (_tabs.size() == 1)
         {
-            return;
+            _lastTabClosedHandlers();
         }
-
         uint32_t tabIndexFromControl = 0;
         _tabView.Items().IndexOf(tabViewItem, tabIndexFromControl);
 
@@ -885,4 +884,5 @@ namespace winrt::TerminalApp::implementation
     // Winrt events need a method for adding a callback to the event and removing the callback.
     // These macros will define them both for you.
     DEFINE_EVENT(App, TitleChanged, _titleChangeHandlers, TerminalControl::TitleChangedEventArgs);
+    DEFINE_EVENT(App, LastTabClosed, _lastTabClosedHandlers, winrt::TerminalApp::LastTabClosedEventArgs);
 }

src/cascadia/TerminalApp/App.h

@@ -44,6 +44,7 @@ namespace winrt::TerminalApp::implementation
 
         // -------------------------------- WinRT Events ---------------------------------
         DECLARE_EVENT(TitleChanged, _titleChangeHandlers, winrt::Microsoft::Terminal::TerminalControl::TitleChangedEventArgs);
+        DECLARE_EVENT(LastTabClosed, _lastTabClosedHandlers, winrt::TerminalApp::LastTabClosedEventArgs);
 
     private:
         App(Windows::UI::Xaml::Markup::IXamlMetadataProvider const& parentProvider);

src/cascadia/TerminalApp/App.idl

@@ -3,6 +3,7 @@
 
 namespace TerminalApp
 {
+    delegate void LastTabClosedEventArgs();
     [default_interface]
     runtimeclass App : Microsoft.UI.Xaml.Markup.XamlApplication
     {
@@ -24,6 +25,7 @@ namespace TerminalApp
         Boolean GetShowTabsInTitlebar();
 
         event Microsoft.Terminal.TerminalControl.TitleChangedEventArgs TitleChanged;
+        event LastTabClosedEventArgs LastTabClosed;
 
         String GetTitle();
 

src/cascadia/WindowsTerminal/AppHost.cpp

@@ -70,6 +70,7 @@ void AppHost::Initialize()
     _app.Create();
 
     _app.TitleChanged({ this, &AppHost::AppTitleChanged });
+    _app.LastTabClosed({ this, &AppHost::LastTabClosed });
 
     AppTitleChanged(_app.GetTitle());
 
@@ -93,6 +94,16 @@ void AppHost::AppTitleChanged(winrt::hstring newTitle)
     _window->UpdateTitle(newTitle.c_str());
 }
 
+// Method Description:
+// - Called when no tab is remaining to close the window.
+// Arguments:
+// - <none>
+// Return Value:
+// - <none>
+void AppHost::LastTabClosed() {
+    _window->Close();
+}
+
 // Method Description:
 // - Resize the window we're about to create to the appropriate dimensions, as
 //   specified in the settings. This will be called during the handling of

src/cascadia/WindowsTerminal/AppHost.h

@@ -15,7 +15,7 @@ public:
     virtual ~AppHost();
 
     void AppTitleChanged(winrt::hstring newTitle);
-
+    void LastTabClosed();
     void Initialize();
 
 private:

src/cascadia/WindowsTerminal/IslandWindow.cpp

@@ -61,6 +61,17 @@ void IslandWindow::MakeWindow() noexcept
 
 }
 
+// Method Description:
+// - Called when no tab is remaining to close the window.
+// Arguments:
+// - <none>
+// Return Value:
+// - <none>
+void IslandWindow::Close()
+{
+    PostQuitMessage(0);
+}
+
 // Method Description:
 // - Set a callback to be called when we process a WM_CREATE message. This gives
 //   the AppHost a chance to resize the window to the propoer size.

src/cascadia/WindowsTerminal/IslandWindow.h

@@ -13,7 +13,7 @@ public:
     virtual ~IslandWindow() override;
 
     void MakeWindow() noexcept;
-
+    void Close();
     virtual void OnSize();
 
     virtual LRESULT MessageHandler(UINT const message, WPARAM const wparam, LPARAM const lparam) noexcept override;