LibGUI+WindowServer: Make DragOperation hold a MimeData instance

...instead of maybe bitmap + a single mime type and its corresponding data.
This allows drag&drop operations to hold multiple different kinds of
data, and the views/applications to choose between those.
For instance, Spreadsheet can keep the structure of the dragged cells,
and still provide text-only data to be passed to different unrelated editors.

Libraries/LibCore/MimeData.h

@@ -55,8 +55,14 @@ public:
     Vector<URL> urls() const;
     void set_urls(const Vector<URL>&);
 
+    const HashMap<String, ByteBuffer>& all_data() const { return m_data; }
+
 private:
     MimeData() { }
+    explicit MimeData(const HashMap<String, ByteBuffer>& data)
+        : m_data(data)
+    {
+    }
 
     HashMap<String, ByteBuffer> m_data;
 };

Libraries/LibGUI/AbstractView.cpp

@@ -291,33 +291,7 @@ void AbstractView::mousemove_event(MouseEvent& event)
     dbg() << "Initiate drag!";
     auto drag_operation = DragOperation::construct();
 
-    RefPtr<Gfx::Bitmap> bitmap;
-
-    StringBuilder text_builder;
-    StringBuilder data_builder;
-    bool first = true;
-    m_selection.for_each_index([&](auto& index) {
-        auto text_data = index.data();
-        if (!first)
-            text_builder.append(", ");
-        text_builder.append(text_data.to_string());
-
-        auto drag_data = index.data(ModelRole::DragData);
-        data_builder.append(drag_data.to_string());
-        data_builder.append('\n');
-
-        first = false;
-
-        if (!bitmap) {
-            Variant icon_data = index.data(ModelRole::Icon);
-            if (icon_data.is_icon())
-                bitmap = icon_data.as_icon().bitmap_for_size(32);
-        }
-    });
-
-    drag_operation->set_text(text_builder.to_string());
-    drag_operation->set_bitmap(bitmap);
-    drag_operation->set_data(data_type, data_builder.to_string());
+    drag_operation->set_mime_data(m_model->mime_data(m_selection));
 
     auto outcome = drag_operation->exec();
 

Libraries/LibGUI/DragOperation.cpp

@@ -27,6 +27,7 @@
 #include <AK/Badge.h>
 #include <AK/SharedBuffer.h>
 #include <LibCore/EventLoop.h>
+#include <LibCore/MimeData.h>
 #include <LibGUI/DragOperation.h>
 #include <LibGUI/WindowServerConnection.h>
 #include <LibGfx/Bitmap.h>
@@ -48,18 +49,25 @@ DragOperation::Outcome DragOperation::exec()
 {
     ASSERT(!s_current_drag_operation);
     ASSERT(!m_event_loop);
+    ASSERT(m_mime_data);
 
     int bitmap_id = -1;
     Gfx::IntSize bitmap_size;
     RefPtr<Gfx::Bitmap> shared_bitmap;
-    if (m_bitmap) {
-        shared_bitmap = m_bitmap->to_bitmap_backed_by_shared_buffer();
+    if (m_mime_data->has_format("image/x-raw-bitmap")) {
+        auto data = m_mime_data->data("image/x-raw-bitmap");
+        auto bitmap = Gfx::Bitmap::create_from_serialized_byte_buffer(move(data));
+        shared_bitmap = bitmap->to_bitmap_backed_by_shared_buffer();
         shared_bitmap->shared_buffer()->share_with(WindowServerConnection::the().server_pid());
         bitmap_id = shared_bitmap->shbuf_id();
         bitmap_size = shared_bitmap->size();
     }
 
-    auto response = WindowServerConnection::the().send_sync<Messages::WindowServer::StartDrag>(m_text, m_data_type, m_data, bitmap_id, bitmap_size);
+    auto response = WindowServerConnection::the().send_sync<Messages::WindowServer::StartDrag>(
+        m_mime_data->text(),
+        m_mime_data->all_data(),
+        bitmap_id, bitmap_size);
+
     if (!response->started()) {
         m_outcome = Outcome::Cancelled;
         return m_outcome;
@@ -94,4 +102,24 @@ void DragOperation::notify_cancelled(Badge<WindowServerConnection>)
     s_current_drag_operation->done(Outcome::Cancelled);
 }
 
+void DragOperation::set_text(const String& text)
+{
+    if (!m_mime_data)
+        m_mime_data = Core::MimeData::construct();
+    m_mime_data->set_text(text);
+}
+void DragOperation::set_bitmap(const Gfx::Bitmap* bitmap)
+{
+    if (!m_mime_data)
+        m_mime_data = Core::MimeData::construct();
+    if (bitmap)
+        m_mime_data->set_data("image/x-raw-bitmap", bitmap->serialize_to_byte_buffer());
+}
+void DragOperation::set_data(const String& data_type, const String& data)
+{
+    if (!m_mime_data)
+        m_mime_data = Core::MimeData::construct();
+    m_mime_data->set_data(data_type, data.to_byte_buffer());
+}
+
 }

Libraries/LibGUI/DragOperation.h

@@ -44,13 +44,10 @@ public:
 
     virtual ~DragOperation() override;
 
-    void set_text(const String& text) { m_text = text; }
-    void set_bitmap(const Gfx::Bitmap* bitmap) { m_bitmap = bitmap; }
-    void set_data(const String& data_type, const String& data)
-    {
-        m_data_type = data_type;
-        m_data = data;
-    }
+    void set_mime_data(RefPtr<Core::MimeData> mime_data) { m_mime_data = move(mime_data); }
+    void set_text(const String& text);
+    void set_bitmap(const Gfx::Bitmap* bitmap);
+    void set_data(const String& data_type, const String& data);
 
     Outcome exec();
     Outcome outcome() const { return m_outcome; }
@@ -66,10 +63,7 @@ private:
 
     OwnPtr<Core::EventLoop> m_event_loop;
     Outcome m_outcome { Outcome::None };
-    String m_text;
-    String m_data_type;
-    String m_data;
-    RefPtr<Gfx::Bitmap> m_bitmap;
+    RefPtr<Core::MimeData> m_mime_data;
 };
 
 }

Libraries/LibGUI/FileSystemModel.cpp

@@ -403,7 +403,7 @@ Variant FileSystemModel::data(const ModelIndex& index, ModelRole role) const
         return node.full_path();
     }
 
-    if (role == ModelRole::DragData) {
+    if (role == ModelRole::MimeData) {
         if (index.column() == Column::Name) {
             StringBuilder builder;
             builder.append("file://");

Libraries/LibGUI/Model.cpp

@@ -88,4 +88,40 @@ void Model::unregister_client(ModelClient& client)
     m_clients.remove(&client);
 }
 
+RefPtr<Core::MimeData> Model::mime_data(const ModelSelection& selection) const
+{
+    auto mime_data = Core::MimeData::construct();
+    RefPtr<Gfx::Bitmap> bitmap;
+
+    StringBuilder text_builder;
+    StringBuilder data_builder;
+    bool first = true;
+    selection.for_each_index([&](auto& index) {
+        auto text_data = index.data();
+        if (!first)
+            text_builder.append(", ");
+        text_builder.append(text_data.to_string());
+
+        if (!first)
+            data_builder.append('\n');
+        auto data = index.data(ModelRole::MimeData);
+        data_builder.append(data.to_string());
+
+        first = false;
+
+        if (!bitmap) {
+            Variant icon_data = index.data(ModelRole::Icon);
+            if (icon_data.is_icon())
+                bitmap = icon_data.as_icon().bitmap_for_size(32);
+        }
+    });
+
+    mime_data->set_data(drag_data_type(), data_builder.to_byte_buffer());
+    mime_data->set_text(text_builder.to_string());
+    if (bitmap)
+        mime_data->set_data("image/x-raw-bitmap", bitmap->serialize_to_byte_buffer());
+
+    return mime_data;
+}
+
 }

Libraries/LibGUI/Model.h

@@ -31,8 +31,10 @@
 #include <AK/HashTable.h>
 #include <AK/RefCounted.h>
 #include <AK/String.h>
+#include <LibCore/MimeData.h>
 #include <LibGUI/ModelIndex.h>
 #include <LibGUI/ModelRole.h>
+#include <LibGUI/ModelSelection.h>
 #include <LibGUI/Variant.h>
 #include <LibGfx/Forward.h>
 #include <LibGfx/TextAlignment.h>
@@ -93,6 +95,7 @@ public:
     }
 
     virtual StringView drag_data_type() const { return {}; }
+    virtual RefPtr<Core::MimeData> mime_data(const ModelSelection&) const;
 
     void register_view(Badge<AbstractView>, AbstractView&);
     void unregister_view(Badge<AbstractView>, AbstractView&);

Libraries/LibGUI/ModelRole.h

@@ -35,7 +35,7 @@ enum class ModelRole {
     BackgroundColor,
     Icon,
     Font,
-    DragData,
+    MimeData,
     TextAlignment,
     Search,
     Custom = 0x100, // Applications are free to use roles above this number as they please

Libraries/LibGUI/WindowServerConnection.cpp

@@ -307,8 +307,7 @@ void WindowServerConnection::handle(const Messages::WindowClient::AsyncSetWallpa
 void WindowServerConnection::handle(const Messages::WindowClient::DragDropped& message)
 {
     if (auto* window = Window::from_window_id(message.window_id())) {
-        auto mime_data = Core::MimeData::construct();
-        mime_data->set_data(message.data_type(), message.data().to_byte_buffer());
+        auto mime_data = Core::MimeData::construct(message.mime_data());
         Core::EventLoop::current().post_event(*window, make<DropEvent>(message.mouse_position(), message.text(), mime_data));
     }
 }