Add drag-n-drop support to be able to re-integrate the dive list

This is somewhat hacky, and there is clearly something I still don't
understand about gtk selections and drag-n-drop.  Dropping it back
works, but I get a nasty error when I do it:

   (subsurface:8512): Gtk-CRITICAL **: IA__gtk_selection_data_set: assertion `length <= 0' failed

even though I actually never set any selection at all directly.  So
there must be some internal gtk rule that I am violating, but I can't
see what it is.

I probably shouldn't commit it with a known ugly wart like that, but I
really have no clue.  Maybe somebody else can figure out what is up.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/gtk-gui.c b/gtk-gui.c
index da2a94dc192c21a9701145fddb434015eca6018a..e1140cbe089921a3641a42bf641ce7d1200e21ad 100644 (file)
--- a/gtk-gui.c
+++ b/gtk-gui.c
@@ -460,6 +460,9 @@ static void switch_page(GtkNotebook *notebook, gint arg1, gpointer user_data)
        repaint_dive();
 }
 
+static const char notebook_group[] = "123";
+#define GRP_ID ((void *)notebook_group)
+
 static GtkNotebook *create_new_notebook_window(GtkNotebook *source,
                GtkWidget *page,
                gint x, gint y, gpointer data)
@@ -482,7 +485,7 @@ static GtkNotebook *create_new_notebook_window(GtkNotebook *source,
        gtk_container_add(GTK_CONTAINER(win), vbox);
 
        notebook = gtk_notebook_new();
-       gtk_notebook_set_group_id(GTK_NOTEBOOK(notebook), gtk_notebook_get_group_id(source));
+       gtk_notebook_set_group(GTK_NOTEBOOK(notebook), GRP_ID);
        gtk_box_pack_start(GTK_BOX(vbox), notebook, TRUE, TRUE, 6);
        gtk_widget_set_size_request(notebook, 350, 250);
 
@@ -490,6 +493,40 @@ static GtkNotebook *create_new_notebook_window(GtkNotebook *source,
        return GTK_NOTEBOOK(notebook);
 }
 
+static void drag_cb(GtkWidget *widget, GdkDragContext *context,
+       gint x, gint y,
+       GtkSelectionData *selection_data,
+       guint info, guint time,
+       gpointer user_data)
+{
+       GtkWidget *source, *target;
+       GtkWidget *tab;
+
+       /*
+        * We don't actually really *use* this yet, but Dirk wants to
+        * do all the tabs as detatched tabs, and we'd need to use
+        * this all to figure out which window we're talking about.
+        */
+       source = gtk_drag_get_source_widget(context);
+       target = (GtkWidget *) user_data;
+       tab = *(GtkWidget **)selection_data->data;
+
+       gtk_drag_finish(context, TRUE, TRUE, time);
+
+       /*
+        * Horrible, horrible hack. We hide the old divelist window, and
+        * set it to NULL. So if we drag the thing back out, we'll create
+        * a new window. Ugh.
+        *
+        * Actually destroying the divelist window triggers the whole
+        * destroy callback, which we don't want.
+        */
+       if (source != target) {
+               gtk_widget_hide(divelist_window);
+               divelist_window = NULL;
+       }
+}
+
 void init_ui(int argc, char **argv)
 {
        GtkWidget *win;
@@ -499,6 +536,9 @@ void init_ui(int argc, char **argv)
        GtkWidget *equipment;
        GtkWidget *menubar;
        GtkWidget *vbox;
+       static const GtkTargetEntry notebook_target = {
+               "GTK_NOTEBOOK_TAB", GTK_TARGET_SAME_APP, 0
+       };
 
        gtk_init(&argc, &argv);
 
@@ -539,13 +579,17 @@ void init_ui(int argc, char **argv)
        /* Notebook for dive info vs profile vs .. */
        notebook = gtk_notebook_new();
        gtk_box_pack_start(GTK_BOX(vbox), notebook, TRUE, TRUE, 6);
+       gtk_notebook_set_group(GTK_NOTEBOOK(notebook), GRP_ID);
        gtk_notebook_set_window_creation_hook(create_new_notebook_window, NULL, NULL);
+       gtk_drag_dest_set(notebook, GTK_DEST_DEFAULT_ALL, &notebook_target, 1, GDK_ACTION_MOVE);
+       g_signal_connect(notebook, "drag-data-received", G_CALLBACK(drag_cb), notebook);
        g_signal_connect(notebook, "switch-page", G_CALLBACK(switch_page), NULL);
 
        /* Create the actual divelist */
        dive_list = dive_list_create();
        gtk_notebook_append_page(GTK_NOTEBOOK(notebook), dive_list, gtk_label_new("Dive List"));
        gtk_notebook_set_tab_detachable(GTK_NOTEBOOK(notebook), dive_list, 1);
+       gtk_notebook_set_tab_reorderable(GTK_NOTEBOOK(notebook), dive_list, 1);
 
        /* Frame for dive profile */
        dive_profile = dive_profile_widget();