Add support for dragging and dropping paths onto the Terminal

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

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
-  <!-- 
-    Microsoft ResX Schema 
-    
+  <!--
+    Microsoft ResX Schema
+
     Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
+
+    The primary goals of this format is to allow a simple XML format
+    that is mostly human readable. The generation and parsing of the
+    various data types are done through the TypeConverter classes
     associated with the data types.
-    
+
     Example:
-    
+
     ... ado.net/XML headers & schema ...
     <resheader name="resmimetype">text/microsoft-resx</resheader>
     <resheader name="version">2.0</resheader>
@@ -26,36 +26,36 @@
         <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
         <comment>This is a comment</comment>
     </data>
-                
-    There are any number of "resheader" rows that contain simple 
+
+    There are any number of "resheader" rows that contain simple
     name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
+
+    Each data row contains a name, and value. The row also contains a
+    type or mimetype. Type corresponds to a .NET class that support
+    text/value conversion through the TypeConverter architecture.
+    Classes that don't support this are serialized and stored with the
     mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
+
+    The mimetype is used for serialized objects, and tells the
+    ResXResourceReader how to depersist the object. This is currently not
     extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format
+    that the ResXResourceWriter will generate, however the reader can
     read any of the formats listed below.
-    
+
     mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
             : and then encoded with base64 encoding.
-    
+
     mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
             : and then encoded with base64 encoding.
 
     mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
+    value   : The object must be serialized into a byte array
             : using a System.ComponentModel.TypeConverter
             : and then encoded with base64 encoding.
     -->
@@ -137,4 +137,7 @@
     <value>Find...</value>
     <comment>The placeholder text in the search dialog TextBox</comment>
   </data>
-</root>
+  <data name="DragFileCaption" xml:space="preserve">
+    <value>Copy path to file</value>
+  </data>
+</root>

src/cascadia/TerminalControl/TermControl.cpp

@@ -9,6 +9,7 @@
 #include <Utf16Parser.hpp>
 #include <Utils.h>
 #include <WinUser.h>
+#include <LibraryResources.h>
 #include "..\..\types\inc\GlyphWidth.hpp"
 
 #include "TermControl.g.cpp"
@@ -21,6 +22,7 @@ using namespace winrt::Windows::UI::Xaml::Automation::Peers;
 using namespace winrt::Windows::UI::Core;
 using namespace winrt::Windows::System;
 using namespace winrt::Microsoft::Terminal::Settings;
+using namespace winrt::Windows::ApplicationModel::DataTransfer;
 
 namespace winrt::Microsoft::Terminal::TerminalControl::implementation
 {
@@ -162,6 +164,10 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         _connectionStateChangedRevoker = _connection.StateChanged(winrt::auto_revoke, [this](auto&& /*s*/, auto&& /*v*/) {
             _ConnectionStateChangedHandlers(*this, nullptr);
         });
+
+        _root.AllowDrop(true);
+        _root.Drop({ get_weak(), &TermControl::_DragDropHandler });
+        _root.DragOver({ get_weak(), &TermControl::_DragOverHandler });
     }
 
     // Method Description:
@@ -1390,6 +1396,12 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         }
     }
 
+    // Method Description:
+    // - Writes the given sequence as input to the active terminal connection,
+    // Arguments:
+    // - wstr: the string of characters to write to the terminal connection.
+    // Return Value:
+    // - <none>
     void TermControl::_SendInputToConnection(const std::wstring& wstr)
     {
         _connection.WriteInput(wstr);
@@ -2150,6 +2162,95 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         return std::pow(cursorDistanceFromBorder, 2.0) / 25.0 + 2.0;
     }
 
+    // Method Description:
+    // - Async handler for the "Drop" event. If a file was dropped onto our
+    //   root, we'll try to get the path of the file dropped onto us, and write
+    //   the full path of the file to our terminal connection. Like conhost, if
+    //   the path contains a space, we'll wrap the path in quotes.
+    // - Unlike conhost, if multiple files are dropped onto the terminal, we'll
+    //   write all the paths to the terminal, separated by spaces.
+    // Arguments:
+    // - e: The DragEventArgs from the Drop event
+    // Return Value:
+    // - <none>
+    winrt::fire_and_forget TermControl::_DoDragDrop(DragEventArgs const e)
+    {
+        if (e.DataView().Contains(StandardDataFormats::StorageItems()))
+        {
+            auto items = co_await e.DataView().GetStorageItemsAsync();
+            if (items.Size() > 0)
+            {
+                std::wstring allPaths;
+                for (auto item : items)
+                {
+                    // Join the paths with spaces
+                    if (!allPaths.empty())
+                    {
+                        allPaths += L" ";
+                    }
+
+                    std::wstring fullPath{ item.Path() };
+                    const auto containsSpaces = std::find(fullPath.begin(),
+                                                          fullPath.end(),
+                                                          L' ') != fullPath.end();
+
+                    auto lock = _terminal->LockForWriting();
+
+                    if (containsSpaces)
+                    {
+                        fullPath.insert(0, L"\"");
+                        fullPath += L"\"";
+                    }
+
+                    allPaths += fullPath;
+                }
+                _SendInputToConnection(allPaths);
+            }
+        }
+    }
+
+    // Method Description:
+    // - Synchronous handler for the "Drop" event. We'll dispatch the async
+    //   _DoDragDrop method to handle this, because getting information about
+    //   the file that was potentially dropped onto us must be done off the UI
+    //   thread.
+    // Arguments:
+    // - e: The DragEventArgs from the Drop event
+    // Return Value:
+    // - <none>
+    void TermControl::_DragDropHandler(Windows::Foundation::IInspectable const& /*sender*/,
+                                       DragEventArgs const& e)
+    {
+        // Dispatch an async method to handle the drop event.
+        _DoDragDrop(e);
+    }
+
+    // Method Description:
+    // - Handle the DragOver event. We'll signal that the drag operation we
+    //   support is the "copy" operation, and we'll also customize the
+    //   appearance of the drag-drop UI, by removing the preview and setting a
+    //   custom caption. For more information, see
+    //   https://docs.microsoft.com/en-us/windows/uwp/design/input/drag-and-drop#customize-the-ui
+    // Arguments:
+    // - e: The DragEventArgs from the DragOver event
+    // Return Value:
+    // - <none>
+    void TermControl::_DragOverHandler(Windows::Foundation::IInspectable const& /*sender*/,
+                                       DragEventArgs const& e)
+    {
+        // Make sure to set the AcceptedOperation, so that we can later recieve the path in the Drop event
+        e.AcceptedOperation(winrt::Windows::ApplicationModel::DataTransfer::DataPackageOperation::Copy);
+
+        // Sets custom UI text
+        e.DragUIOverride().Caption(RS_(L"DragFileCaption"));
+        // Sets if the caption is visible
+        e.DragUIOverride().IsCaptionVisible(true);
+        // Sets if the dragged content is visible
+        e.DragUIOverride().IsContentVisible(false);
+        // Sets if the glyph is visibile
+        e.DragUIOverride().IsGlyphVisible(false);
+    }
+
     // -------------------------------- WinRT Events ---------------------------------
     // Winrt events need a method for adding a callback to the event and removing the callback.
     // These macros will define them both for you.

src/cascadia/TerminalControl/TermControl.h

@@ -187,6 +187,9 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         void _ScrollbarChangeHandler(Windows::Foundation::IInspectable const& sender, Windows::UI::Xaml::Controls::Primitives::RangeBaseValueChangedEventArgs const& e);
         void _GotFocusHandler(Windows::Foundation::IInspectable const& sender, Windows::UI::Xaml::RoutedEventArgs const& e);
         void _LostFocusHandler(Windows::Foundation::IInspectable const& sender, Windows::UI::Xaml::RoutedEventArgs const& e);
+        void _DragDropHandler(Windows::Foundation::IInspectable const& sender, Windows::UI::Xaml::DragEventArgs const& e);
+        void _DragOverHandler(Windows::Foundation::IInspectable const& sender, Windows::UI::Xaml::DragEventArgs const& e);
+        winrt::fire_and_forget _DoDragDrop(Windows::UI::Xaml::DragEventArgs const e);
 
         void _BlinkCursor(Windows::Foundation::IInspectable const& sender, Windows::Foundation::IInspectable const& e);
         void _SetEndSelectionPointAtCursor(Windows::Foundation::Point const& cursorPosition);

src/cascadia/TerminalControl/pch.h

@@ -37,6 +37,8 @@
 #include <winrt/Windows.UI.Xaml.Input.h>
 #include <winrt/Windows.UI.Xaml.Interop.h>
 #include <winrt/Windows.ui.xaml.markup.h>
+#include <winrt/Windows.ApplicationModel.DataTransfer.h>
+#include <winrt/Windows.Storage.h>
 
 #include <windows.ui.xaml.media.dxinterop.h>