Add shield to tab row when elevated (#11224)

## Summary of the Pull Request

Adds a visible indicator that a Terminal window is elevated. This icon can be disabled with `"showAdminShield" false` in the global settings.

## References

* spec'd in #8455 
* Also in https://github.com/microsoft/terminal/projects/5
* big picture: #5000

## PR Checklist
* [x] Closes #1939
* [x] I work here
* [n/a] Tests added/passed
* [ ] Requires documentation to be updated - yea probably

## Validation Steps Performed

![image](https://user-images.githubusercontent.com/18356694/133293009-4215e319-fbf9-4ca8-8af5-afe2fa8bb62d.png)

![image](https://user-images.githubusercontent.com/18356694/133292970-90cb17fd-16c7-429a-a25f-8457850eb278.png)

doc/cascadia/profiles.schema.json

@@ -1274,6 +1274,11 @@
           "description": "When set to true, the Terminal's notification icon will always be shown in the notification area.",
           "type": "boolean"
         },
+        "showAdminShield": {
+          "default": "true",
+          "description": "When set to true, the Terminal's tab row will display a shield icon when the Terminal is running with administrator privileges",
+          "type": "boolean"
+        },
         "useAcrylicInTabRow": {
           "default": "false",
           "description": "When set to true, the tab row will have an acrylic background with 50% opacity.",

src/cascadia/TerminalApp/Resources/en-US/Resources.resw

@@ -715,4 +715,7 @@
   <data name="InfoBarDismissButton.Content" xml:space="preserve">
     <value>Don't show again</value>
   </data>
+  <data name="ElevationShield.[using:Windows.UI.Xaml.Controls]ToolTipService.ToolTip" xml:space="preserve">
+    <value>This Terminal window is running as Admin</value>
+  </data>
 </root>

src/cascadia/TerminalApp/TabRowControl.h

@@ -4,6 +4,7 @@
 #pragma once
 
 #include "winrt/Microsoft.UI.Xaml.Controls.h"
+#include "../../cascadia/inc/cppwinrt_utils.h"
 
 #include "TabRowControl.g.h"
 
@@ -16,6 +17,9 @@ namespace winrt::TerminalApp::implementation
         void OnNewTabButtonClick(Windows::Foundation::IInspectable const& sender, Microsoft::UI::Xaml::Controls::SplitButtonClickEventArgs const& args);
         void OnNewTabButtonDrop(winrt::Windows::Foundation::IInspectable const& sender, winrt::Windows::UI::Xaml::DragEventArgs const& e);
         void OnNewTabButtonDragOver(winrt::Windows::Foundation::IInspectable const& sender, winrt::Windows::UI::Xaml::DragEventArgs const& e);
+
+        WINRT_CALLBACK(PropertyChanged, Windows::UI::Xaml::Data::PropertyChangedEventHandler);
+        WINRT_OBSERVABLE_PROPERTY(bool, ShowElevationShield, _PropertyChangedHandlers, false);
     };
 }
 

src/cascadia/TerminalApp/TabRowControl.idl

@@ -3,9 +3,11 @@
 
 namespace TerminalApp
 {
-    [default_interface] runtimeclass TabRowControl : Windows.UI.Xaml.Controls.ContentPresenter
+    [default_interface] runtimeclass TabRowControl : Windows.UI.Xaml.Controls.ContentPresenter,
+                                                     Windows.UI.Xaml.Data.INotifyPropertyChanged
     {
         TabRowControl();
         Microsoft.UI.Xaml.Controls.TabView TabView { get; };
+        Boolean ShowElevationShield;
     }
 }

src/cascadia/TerminalApp/TabRowControl.xaml

@@ -20,6 +20,17 @@
                  IsAddTabButtonVisible="false"
                  TabWidthMode="Equal">
 
+        <mux:TabView.TabStripHeader>
+            <!--  EA18 is the "Shield" glyph  -->
+            <FontIcon x:Uid="ElevationShield"
+                      Margin="9,4,0,0"
+                      FontFamily="Segoe MDL2 Assets"
+                      FontSize="16"
+                      Foreground="{ThemeResource SystemControlForegroundBaseMediumBrush}"
+                      Glyph="&#xEA18;"
+                      Visibility="{x:Bind ShowElevationShield, Mode=OneWay}" />
+        </mux:TabView.TabStripHeader>
+
         <mux:TabView.TabStripFooter>
             <mux:SplitButton x:Name="NewTabButton"
                              x:Uid="NewTabSplitButton"

src/cascadia/TerminalApp/TerminalPage.cpp

@@ -118,6 +118,29 @@ namespace winrt::TerminalApp::implementation
         _systemRowsToScroll = _ReadSystemRowsToScroll();
     }
 
+    bool TerminalPage::IsElevated() const noexcept
+    {
+        // use C++11 magic statics to make sure we only do this once.
+        // This won't change over the lifetime of the application
+
+        static const bool isElevated = []() {
+            // *** THIS IS A SINGLETON ***
+            auto result = false;
+
+            // GH#2455 - Make sure to try/catch calls to Application::Current,
+            // because that _won't_ be an instance of TerminalApp::App in the
+            // LocalTests
+            try
+            {
+                result = ::winrt::Windows::UI::Xaml::Application::Current().as<::winrt::TerminalApp::App>().Logic().IsElevated();
+            }
+            CATCH_LOG();
+            return result;
+        }();
+
+        return isElevated;
+    }
+
     void TerminalPage::Create()
     {
         // Hookup the key bindings
@@ -128,19 +151,7 @@ namespace winrt::TerminalApp::implementation
         _tabView = _tabRow.TabView();
         _rearranging = false;
 
-        // GH#2455 - Make sure to try/catch calls to Application::Current,
-        // because that _won't_ be an instance of TerminalApp::App in the
-        // LocalTests
-        auto isElevated = false;
-        try
-        {
-            // GH#3581 - There's a platform limitation that causes us to crash when we rearrange tabs.
-            // Xaml tries to send a drag visual (to wit: a screenshot) to the drag hosting process,
-            // but that process is running at a different IL than us.
-            // For now, we're disabling elevated drag.
-            isElevated = ::winrt::Windows::UI::Xaml::Application::Current().as<::winrt::TerminalApp::App>().Logic().IsElevated();
-        }
-        CATCH_LOG();
+        const auto isElevated = IsElevated();
 
         if (_settings.GlobalSettings().UseAcrylicInTabRow())
         {
@@ -267,6 +278,8 @@ namespace winrt::TerminalApp::implementation
         // Setup mouse vanish attributes
         SystemParametersInfoW(SPI_GETMOUSEVANISH, 0, &_shouldMouseVanish, false);
 
+        _tabRow.ShowElevationShield(IsElevated() && _settings.GlobalSettings().ShowAdminShield());
+
         // Store cursor, so we can restore it, e.g., after mouse vanishing
         // (we'll need to adapt this logic once we make cursor context aware)
         try
@@ -2242,6 +2255,8 @@ namespace winrt::TerminalApp::implementation
         // enabled application-wide, so we don't need to check it each time we
         // want to create an animation.
         WUX::Media::Animation::Timeline::AllowDependentAnimations(!_settings.GlobalSettings().DisableAnimations());
+
+        _tabRow.ShowElevationShield(IsElevated() && _settings.GlobalSettings().ShowAdminShield());
     }
 
     // This is a helper to aid in sorting commands by their `Name`s, alphabetically.

src/cascadia/TerminalApp/TerminalPage.h

@@ -115,6 +115,7 @@ namespace winrt::TerminalApp::implementation
         winrt::hstring WindowIdForDisplay() const noexcept;
         winrt::hstring WindowNameForDisplay() const noexcept;
         bool IsQuakeWindow() const noexcept;
+        bool IsElevated() const noexcept;
 
         WINRT_CALLBACK(PropertyChanged, Windows::UI::Xaml::Data::PropertyChangedEventHandler);
 

src/cascadia/TerminalSettingsModel/GlobalAppSettings.cpp

@@ -51,6 +51,7 @@ static constexpr std::string_view TrimBlockSelectionKey{ "trimBlockSelection" };
 static constexpr std::string_view AlwaysShowNotificationIconKey{ "alwaysShowNotificationIcon" };
 static constexpr std::string_view MinimizeToNotificationAreaKey{ "minimizeToNotificationArea" };
 static constexpr std::string_view DisabledProfileSourcesKey{ "disabledProfileSources" };
+static constexpr std::string_view ShowAdminShieldKey{ "showAdminShield" };
 
 static constexpr std::string_view DebugFeaturesKey{ "debugFeatures" };
 
@@ -121,6 +122,8 @@ winrt::com_ptr<GlobalAppSettings> GlobalAppSettings::Copy() const
     globals->_MinimizeToNotificationArea = _MinimizeToNotificationArea;
     globals->_AlwaysShowNotificationIcon = _AlwaysShowNotificationIcon;
     globals->_DisabledProfileSources = _DisabledProfileSources;
+    globals->_ShowAdminShield = _ShowAdminShield;
+
     globals->_UnparsedDefaultProfile = _UnparsedDefaultProfile;
 
     globals->_defaultProfile = _defaultProfile;
@@ -227,6 +230,8 @@ void GlobalAppSettings::LayerJson(const Json::Value& json)
     JsonUtils::GetValueForKey(json, AlwaysShowNotificationIconKey, _AlwaysShowNotificationIcon);
     JsonUtils::GetValueForKey(json, DisabledProfileSourcesKey, _DisabledProfileSources);
 
+    JsonUtils::GetValueForKey(json, ShowAdminShieldKey, _ShowAdminShield);
+
     static constexpr std::array bindingsKeys{ LegacyKeybindingsKey, ActionsKey };
     for (const auto& jsonKey : bindingsKeys)
     {
@@ -324,6 +329,7 @@ Json::Value GlobalAppSettings::ToJson() const
     JsonUtils::SetValueForKey(json, MinimizeToNotificationAreaKey,  _MinimizeToNotificationArea);
     JsonUtils::SetValueForKey(json, AlwaysShowNotificationIconKey,  _AlwaysShowNotificationIcon);
     JsonUtils::SetValueForKey(json, DisabledProfileSourcesKey,      _DisabledProfileSources);
+    JsonUtils::SetValueForKey(json, ShowAdminShieldKey,             _ShowAdminShield);
     // clang-format on
 
     json[JsonKey(ActionsKey)] = _actionMap->ToJson();

src/cascadia/TerminalSettingsModel/GlobalAppSettings.h

@@ -99,6 +99,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         INHERITABLE_SETTING(Model::GlobalAppSettings, bool, AlwaysShowNotificationIcon, false);
         INHERITABLE_SETTING(Model::GlobalAppSettings, winrt::Windows::Foundation::Collections::IVector<winrt::hstring>, DisabledProfileSources, nullptr);
         INHERITABLE_SETTING(Model::GlobalAppSettings, hstring, UnparsedDefaultProfile, L"");
+        INHERITABLE_SETTING(Model::GlobalAppSettings, bool, ShowAdminShield, true);
 
     private:
 #ifdef NDEBUG

src/cascadia/TerminalSettingsModel/GlobalAppSettings.idl

@@ -84,6 +84,7 @@ namespace Microsoft.Terminal.Settings.Model
         INHERITABLE_SETTING(Boolean, MinimizeToNotificationArea);
         INHERITABLE_SETTING(Boolean, AlwaysShowNotificationIcon);
         INHERITABLE_SETTING(IVector<String>, DisabledProfileSources);
+        INHERITABLE_SETTING(Boolean, ShowAdminShield);
 
         Windows.Foundation.Collections.IMapView<String, ColorScheme> ColorSchemes();
         void AddColorScheme(ColorScheme scheme);

src/cascadia/TerminalSettingsModel/defaults.json

@@ -20,6 +20,7 @@
     "showTerminalTitleInTitlebar": true,
     "tabWidthMode": "equal",
     "tabSwitcherMode": "inOrder",
+    "showAdminShield": true,
 
     // Miscellaneous
     "confirmCloseAllTabs": true,