confirm dialogue for new project

source/tycho/main.rs

@@ -138,7 +138,7 @@ unsafe fn setup_about_dlg(b: *mut GtkBuilder)
       gtk_widget_hide(dlg as _);
    }
 
-   let dlg: *mut GtkAboutDialog = get_obj(b, c_str!("win-about"));
+   let dlg: *mut GtkAboutDialog = get_obj(b, c_str!("dlg-about"));
    let btn: *mut GtkMenuItem    = get_obj(b, c_str!("btn-about"));
 
    let it    = env!("CARGO_PKG_AUTHORS").split(';');
@@ -181,10 +181,21 @@ unsafe fn setup_win_main(b: *mut GtkBuilder,
       let edit = edit as *mut Option<MapEditorState>;
       let edit = &mut *edit;
 
+      if let Some(_) = *edit {
+         let titl = c_str!("Confirm");
+         let text = c_str!("Are you sure you want to create a new project? \
+                            Data may be lost.");
+
+         match run_ok_cancel_dlg(titl, text) {
+            true  => {},
+            false => return,
+         }
+      }
+
       *edit = Some(MapEditorState::new());
    }
 
-   /// Callback to destroy the editor state reference.
+   /// Callback to finalize the editor state reference.
    unsafe extern "C" fn c_new_done(_: *mut GtkWidget, edit: gpointer)
    {
       Rc::from_raw(edit);
@@ -212,6 +223,35 @@ unsafe fn setup_css()
    g_object_unref(css as _);
 }
 
+/// Runs a modal OK/Cancel dialogue.
+unsafe fn run_ok_cancel_dlg(title: ffi::NT, text: ffi::NT) -> bool
+{
+   let flags = GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT;
+   let dlg   = gtk_dialog_new_with_buttons(title,
+                                           ffi::null_mut(),
+                                           flags,
+                                           c_str!("_OK"),
+                                           GTK_RESPONSE_ACCEPT,
+                                           c_str!("_Cancel"),
+                                           GTK_RESPONSE_REJECT,
+                                           ffi::null_mut::<gpointer>());
+
+   let area = gtk_dialog_get_content_area(dlg as _);
+   let labl = gtk_label_new(text);
+
+   gtk_container_add(area as _, labl);
+   gtk_widget_show_all(area as _);
+
+   let res = gtk_dialog_run(dlg as _);
+
+   gtk_widget_destroy(dlg);
+
+   match res {
+      GTK_RESPONSE_ACCEPT => true,
+      _                   => false,
+   }
+}
+
 /// Connects a handler that hides a toplevel widget when deleted.
 unsafe fn connect_hide(wid: *mut GtkWidget)
 {