Search - add search box control and implement search experience (#3590)

<!-- Enter a brief description/summary of your PR here. What does it fix/what does it change/how was it tested (even manually, if necessary)? -->
This is the PR for feature Search: #605 
This PR includes the newly introduced SearchBoxControl in TermControl dir, which is the search bar for the search experience. And the codes that enable Search in Windows Terminal. 

<!-- Other than the issue solved, is this relevant to any other issues/existing PRs? --> 
The PR that migrates the Conhost search module: microsoft/terminal#3279
Spec (still actively updating): microsoft/terminal#3299
<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist
* [x] Closes #605 
* [ ] CLA signed. If not, go over [here](https://cla.opensource.microsoft.com/microsoft/Terminal) and sign the CLA
* [ ] Tests added/passed
* [ ] Requires documentation to be updated
* [ ] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #xxx

<!-- Provide a more detailed description of the PR, other things fixed or any additional comments/features here -->
These functionalities are included in the search experience. 
1. Search in Terminal text buffer. 
2. Automatic wrap-around. 
3. Search up or down switch by clicking different buttons.
4. Search case sensitively/insensitively by clicking a button.                                                                                                                                                S. Move the search box to the top/bottom by clicking a button. 
6. Close by clicking 'X'. 
7. Open search by ctrl + F.

When the searchbox is open, the user could still interact with the terminal by clicking the terminal input area. 

While I already have the search functionalities, currently there are still some known to-do works and I will keep updating my PR:

1. Optimize the search box UI, this includes:
                                                  1) Theme adaptation. The search box background and font color 
                                                       should change according to the theme, 
                                                  2) Add background. Currently the elements in search box are all
                                                      transparent. However, we need a background. 
                                                  3) Move button should be highlighted once clicked. 
2. Accessibility: search process should be able to performed without mouse. Once the search box is focused, the user should be able to navigate between all interactive elements on the searchbox using keyboard. 

<!-- Describe how you validated the behavior. Add automated tests wherever possible, but list manual validation steps taken as well -->

To test:
1. checkout this branch.
2. Build the project. 
3. Start Windows Terminal and press Ctrl+F
4. The search box should appear on the top right corner.

doc/cascadia/SettingsSchema.md

@@ -137,7 +137,8 @@ Commands listed below are per the implementation in [`src/cascadia/TerminalApp/A
 - moveFocusRight
 - moveFocusUp
 - moveFocusDown
-- toggleFullscreen
+- toggleFullscreen
+- find
 
 ## Example Keys
 - ctrl+1

src/buffer/out/search.cpp

@@ -97,11 +97,7 @@ bool Search::FindNext()
 // - Takes the found word and selects it in the screen buffer
 void Search::Select() const
 {
-    // Only select if we've found something.
-    if (_coordSelStart != _coordSelEnd)
-    {
-        _uiaData.SelectNewRegion(_coordSelStart, _coordSelEnd);
-    }
+    _uiaData.SelectNewRegion(_coordSelStart, _coordSelEnd);
 }
 
 // Routine Description:
@@ -142,6 +138,7 @@ std::pair<COORD, COORD> Search::GetFoundLocation() const noexcept
 COORD Search::s_GetInitialAnchor(IUiaData& uiaData, const Direction direction)
 {
     const auto& textBuffer = uiaData.GetTextBuffer();
+    const COORD textBufferEndPosition = uiaData.GetTextBufferEndPosition();
     if (uiaData.IsSelectionActive())
     {
         auto anchor = uiaData.GetSelectionAnchor();
@@ -152,6 +149,10 @@ COORD Search::s_GetInitialAnchor(IUiaData& uiaData, const Direction direction)
         else
         {
             textBuffer.GetSize().DecrementInBoundsCircular(anchor);
+            // If the selection starts at (0, 0), we need to make sure
+            // it does not exceed the text buffer end position
+            anchor.X = std::min(textBufferEndPosition.X, anchor.X);
+            anchor.Y = std::min(textBufferEndPosition.Y, anchor.Y);
         }
         return anchor;
     }
@@ -163,8 +164,7 @@ COORD Search::s_GetInitialAnchor(IUiaData& uiaData, const Direction direction)
         }
         else
         {
-            const auto bufferSize = textBuffer.GetSize().Dimensions();
-            return { bufferSize.X - 1, bufferSize.Y - 1 };
+            return textBufferEndPosition;
         }
     }
 }
@@ -293,6 +293,26 @@ void Search::_UpdateNextPosition()
     {
         THROW_HR(E_NOTIMPL);
     }
+
+    // To reduce wrap-around time, if the next position is larger than
+    // the end position of the written text
+    // We put the next position to:
+    // Forward: (0, 0)
+    // Backward: the position of the end of the text buffer
+    const COORD bufferEndPosition = _uiaData.GetTextBufferEndPosition();
+
+    if (_coordNext.Y > bufferEndPosition.Y ||
+        (_coordNext.Y == bufferEndPosition.Y && _coordNext.X > bufferEndPosition.X))
+    {
+        if (_direction == Direction::Forward)
+        {
+            _coordNext = { 0 };
+        }
+        else
+        {
+            _coordNext = bufferEndPosition;
+        }
+    }
 }
 
 // Routine Description:

src/buffer/out/search.h

@@ -59,7 +59,7 @@ class Search final
 
 private:
     wchar_t _ApplySensitivity(const wchar_t wch) const noexcept;
-    bool Search::_FindNeedleInHaystackAt(const COORD pos, COORD& start, COORD& end) const;
+    bool _FindNeedleInHaystackAt(const COORD pos, COORD& start, COORD& end) const;
     bool _CompareChars(const std::wstring_view one, const std::wstring_view two) const noexcept;
     void _UpdateNextPosition();
 

src/cascadia/TerminalApp/AppActionHandlers.cpp

@@ -214,6 +214,13 @@ namespace winrt::TerminalApp::implementation
         }
     }
 
+    void TerminalPage::_HandleFind(const IInspectable& /*sender*/,
+                                   const TerminalApp::ActionEventArgs& args)
+    {
+        _Find();
+        args.Handled(true);
+    }
+
     void TerminalPage::_HandleResetFontSize(const IInspectable& /*sender*/,
                                             const TerminalApp::ActionEventArgs& args)
     {
@@ -228,5 +235,4 @@ namespace winrt::TerminalApp::implementation
         _ToggleFullscreen();
         args.Handled(true);
     }
-
 }

src/cascadia/TerminalApp/AppKeyBindingsSerialization.cpp

@@ -77,6 +77,7 @@ static constexpr std::string_view MoveFocusLeftKey{ "moveFocusLeft" }; // Legacy
 static constexpr std::string_view MoveFocusRightKey{ "moveFocusRight" }; // Legacy
 static constexpr std::string_view MoveFocusUpKey{ "moveFocusUp" }; // Legacy
 static constexpr std::string_view MoveFocusDownKey{ "moveFocusDown" }; // Legacy
+static constexpr std::string_view FindKey{ "find" };
 static constexpr std::string_view ToggleFullscreenKey{ "toggleFullscreen" };
 
 // Specifically use a map here over an unordered_map. We want to be able to
@@ -142,6 +143,7 @@ static const std::map<std::string_view, ShortcutAction, std::less<>> commandName
     { ToggleFullscreenKey, ShortcutAction::ToggleFullscreen },
     { SplitPaneKey, ShortcutAction::SplitPane },
     { UnboundKey, ShortcutAction::Invalid },
+    { FindKey, ShortcutAction::Find },
 };
 
 // Function Description:

src/cascadia/TerminalApp/ShortcutActionDispatch.cpp

@@ -180,6 +180,11 @@ namespace winrt::TerminalApp::implementation
             _AdjustFontSizeHandlers(*this, *eventArgs);
             break;
         }
+        case ShortcutAction::Find:
+        {
+            _FindHandlers(*this, *eventArgs);
+            break;
+        }
         case ShortcutAction::ResetFontSize:
         {
             _ResetFontSizeHandlers(*this, *eventArgs);

src/cascadia/TerminalApp/ShortcutActionDispatch.h

@@ -44,6 +44,7 @@ namespace winrt::TerminalApp::implementation
         TYPED_EVENT(ScrollDownPage,    TerminalApp::ShortcutActionDispatch, TerminalApp::ActionEventArgs);
         TYPED_EVENT(OpenSettings,      TerminalApp::ShortcutActionDispatch, TerminalApp::ActionEventArgs);
         TYPED_EVENT(ResizePane,        TerminalApp::ShortcutActionDispatch, TerminalApp::ActionEventArgs);
+        TYPED_EVENT(Find,              TerminalApp::ShortcutActionDispatch, TerminalApp::ActionEventArgs);
         TYPED_EVENT(MoveFocus,         TerminalApp::ShortcutActionDispatch, TerminalApp::ActionEventArgs);
         TYPED_EVENT(ToggleFullscreen,  TerminalApp::ShortcutActionDispatch, TerminalApp::ActionEventArgs);
         // clang-format on

src/cascadia/TerminalApp/ShortcutActionDispatch.idl

@@ -61,6 +61,7 @@ namespace TerminalApp
         MoveFocusRight, // Legacy
         MoveFocusUp, // Legacy
         MoveFocusDown, // Legacy
+        Find,
         ToggleFullscreen,
         OpenSettings
     };
@@ -97,6 +98,7 @@ namespace TerminalApp
         event Windows.Foundation.TypedEventHandler<ShortcutActionDispatch, ActionEventArgs> ScrollDownPage;
         event Windows.Foundation.TypedEventHandler<ShortcutActionDispatch, ActionEventArgs> OpenSettings;
         event Windows.Foundation.TypedEventHandler<ShortcutActionDispatch, ActionEventArgs> ResizePane;
+        event Windows.Foundation.TypedEventHandler<ShortcutActionDispatch, ActionEventArgs> Find;
         event Windows.Foundation.TypedEventHandler<ShortcutActionDispatch, ActionEventArgs> MoveFocus;
         event Windows.Foundation.TypedEventHandler<ShortcutActionDispatch, ActionEventArgs> ToggleFullscreen;
     }

src/cascadia/TerminalApp/TerminalPage.cpp

@@ -630,7 +630,6 @@ namespace winrt::TerminalApp::implementation
         // Hook up the ShortcutActionDispatch object's events to our handlers.
         // They should all be hooked up here, regardless of whether or not
         // there's an actual keychord for them.
-
         _actionDispatch->OpenNewTabDropdown({ this, &TerminalPage::_HandleOpenNewTabDropdown });
         _actionDispatch->DuplicateTab({ this, &TerminalPage::_HandleDuplicateTab });
         _actionDispatch->CloseTab({ this, &TerminalPage::_HandleCloseTab });
@@ -651,6 +650,7 @@ namespace winrt::TerminalApp::implementation
         _actionDispatch->MoveFocus({ this, &TerminalPage::_HandleMoveFocus });
         _actionDispatch->CopyText({ this, &TerminalPage::_HandleCopyText });
         _actionDispatch->AdjustFontSize({ this, &TerminalPage::_HandleAdjustFontSize });
+        _actionDispatch->Find({ this, &TerminalPage::_HandleFind });
         _actionDispatch->ResetFontSize({ this, &TerminalPage::_HandleResetFontSize });
         _actionDispatch->ToggleFullscreen({ this, &TerminalPage::_HandleToggleFullscreen });
     }
@@ -1417,6 +1417,20 @@ namespace winrt::TerminalApp::implementation
         }
     }
 
+    // Method Description:
+    // - Called when the user tries to do a search using keybindings.
+    //   This will tell the current focused terminal control to create
+    //   a search box and enable find process.
+    // Arguments:
+    // - <none>
+    // Return Value:
+    // - <none>
+    void TerminalPage::_Find()
+    {
+        const auto termControl = _GetActiveControl();
+        termControl.CreateSearchBoxControl();
+    }
+
     // Method Description:
     // - Toggles fullscreen mode. Hides the tab row, and raises our
     //   ToggleFullscreen event.

src/cascadia/TerminalApp/TerminalPage.h

@@ -122,6 +122,8 @@ namespace winrt::TerminalApp::implementation
         void _OnContentSizeChanged(const IInspectable& /*sender*/, Windows::UI::Xaml::SizeChangedEventArgs const& e);
         void _OnTabCloseRequested(const IInspectable& sender, const Microsoft::UI::Xaml::Controls::TabViewTabCloseRequestedEventArgs& eventArgs);
 
+        void _Find();
+
         void _RefreshUIForSettingsReload();
 
         void _ToggleFullscreen();
@@ -148,6 +150,7 @@ namespace winrt::TerminalApp::implementation
         void _HandleCopyText(const IInspectable& sender, const TerminalApp::ActionEventArgs& args);
         void _HandleCloseWindow(const IInspectable&, const TerminalApp::ActionEventArgs& args);
         void _HandleAdjustFontSize(const IInspectable& sender, const TerminalApp::ActionEventArgs& args);
+        void _HandleFind(const IInspectable& sender, const TerminalApp::ActionEventArgs& args);
         void _HandleResetFontSize(const IInspectable& sender, const TerminalApp::ActionEventArgs& args);
         void _HandleToggleFullscreen(const IInspectable& sender, const TerminalApp::ActionEventArgs& args);
 #pragma endregion

src/cascadia/TerminalApp/defaults.json

@@ -245,6 +245,7 @@
         { "command": { "action": "switchToTab", "index": 6 }, "keys": ["ctrl+alt+7"] },
         { "command": { "action": "switchToTab", "index": 7 }, "keys": ["ctrl+alt+8"] },
         { "command": { "action": "switchToTab", "index": 8 }, "keys": ["ctrl+alt+9"] },
+        { "command": "find", "keys": [ "ctrl+shift+f" ] },
         { "command": "toggleFullscreen", "keys": [ "alt+enter" ] },
         { "command": "toggleFullscreen", "keys": [ "f11" ] }
     ]