window: Add drop targets back to tabs

With the introduction of ::extra-drag-value in AdwTabBar, we can
now dynamically set the preferred action on the AdwTabBar.  Use
the "extra" drop target on the AdwTabBar, and use our existing code
making this fairly simple.

Fixes: https://gitlab.gnome.org/GNOME/nautilus/-/issues/2495

2 files changed, 73 insertions, 1 deletions

diff --git a/src/nautilus-window.c b/src/nautilus-window.c
index e0b235013..14f5db48c 100644
--- a/src/nautilus-window.c
+++ b/src/nautilus-window.c
@@ -97,6 +97,7 @@ struct _NautilusWindow
     AdwApplicationWindow parent_instance;
 
     AdwTabView *tab_view;
+    AdwTabBar *tab_bar;
     AdwTabPage *menu_page;
 
     GList *slots;
@@ -1467,6 +1468,63 @@ setup_tab_view (NautilusWindow *window)
                       window);
 }
 
+static GdkDragAction
+extra_drag_value_cb (AdwTabBar    *self,
+                     AdwTabPage   *page,
+                     const GValue *value,
+                     gpointer      user_data)
+{
+    NautilusWindowSlot *slot = NAUTILUS_WINDOW_SLOT (adw_tab_page_get_child (page));
+    g_autoptr (NautilusFile) file = nautilus_file_get (nautilus_window_slot_get_location (slot));
+    GdkDragAction action;
+
+    if (value == NULL)
+    {
+        action = 0;
+    }
+    else if (G_VALUE_HOLDS (value, GDK_TYPE_FILE_LIST))
+    {
+        GSList *file_list = g_value_get_boxed (value);
+
+        if (file_list == NULL)
+        {
+            action = 0;
+        }
+        else
+        {
+            action = nautilus_dnd_get_preferred_action (file, G_FILE (file_list->data));
+        }
+    }
+    else if (G_VALUE_HOLDS (value, G_TYPE_STRING))
+    {
+        action = GDK_ACTION_COPY;
+    }
+
+    /* We set the preferred action on the drop from the results of this function,
+     * but since we don't have access to the GtkDropTarget, we can't get the preferred
+     * action in ::drop, so let's set it as data on the page. We probably should
+     * expose the preferred action within libadwaita.
+     */
+    g_object_set_data (G_OBJECT (page), "drag-action", GINT_TO_POINTER (action));
+    return action;
+}
+
+static gboolean
+extra_drag_drop_cb (AdwTabBar    *self,
+                    AdwTabPage   *page,
+                    const GValue *value,
+                    gpointer      user_data)
+{
+    NautilusWindowSlot *slot = NAUTILUS_WINDOW_SLOT (adw_tab_page_get_child (page));
+    NautilusFilesView *view = NAUTILUS_FILES_VIEW (nautilus_window_slot_get_current_view (slot));
+    GFile *target_location = nautilus_window_slot_get_location (slot);
+    GdkDragAction action = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (page), "drag-action"));
+
+    nautilus_dnd_perform_drop (view, value, action, target_location);
+
+    return TRUE;
+}
+
 const GActionEntry win_entries[] =
 {
     { "back", action_back },
@@ -1578,6 +1636,19 @@ nautilus_window_constructed (GObject *self)
                                  NAUTILUS_WINDOW_DEFAULT_HEIGHT);
 
     setup_tab_view (window);
+
+    /* Lets not support GDK_ACTION_LINK for now.  This only impacts x11
+     * and on x11 we are using a hack in list-base to handle GDK_ACTION_LINK
+     * which we can not replicate here because we don't have access to the
+     * GtkDropTarget to check the actions on the GdkDrag.
+     */
+    adw_tab_bar_setup_extra_drop_target (window->tab_bar,
+                                         GDK_ACTION_COPY | GDK_ACTION_MOVE,
+                                         (GType [2]) {GDK_TYPE_FILE_LIST, G_TYPE_STRING}, 2);
+    adw_tab_bar_set_extra_drag_preload (window->tab_bar, TRUE);
+    g_signal_connect (window->tab_bar, "extra-drag-value", G_CALLBACK (extra_drag_value_cb), NULL);
+    g_signal_connect (window->tab_bar, "extra-drag-drop", G_CALLBACK (extra_drag_drop_cb), NULL);
+
     nautilus_window_set_up_sidebar (window);
 
 
@@ -2227,6 +2298,7 @@ nautilus_window_class_init (NautilusWindowClass *class)
     gtk_widget_class_bind_template_child (wclass, NautilusWindow, places_sidebar);
     gtk_widget_class_bind_template_child (wclass, NautilusWindow, toast_overlay);
     gtk_widget_class_bind_template_child (wclass, NautilusWindow, tab_view);
+    gtk_widget_class_bind_template_child (wclass, NautilusWindow, tab_bar);
 
     signals[SLOT_ADDED] =
         g_signal_new ("slot-added",
diff --git a/src/resources/ui/nautilus-window.ui b/src/resources/ui/nautilus-window.ui
index 5dd2e4b88..31afae73a 100644
--- a/src/resources/ui/nautilus-window.ui
+++ b/src/resources/ui/nautilus-window.ui
@@ -75,7 +75,7 @@
                     <property name="orientation">vertical</property>
                     <property name="width-request">360</property>
                     <child>
-                      <object class="AdwTabBar">
+                      <object class="AdwTabBar" id="tab_bar">
                         <property name="view">tab_view</property>
                       </object>
                     </child>