gtk: application: Use startup signal to log rt startup

The GtkApplication itself will call gtk_init() so we shouldn't
call `rt::init()` here, instead we should hang off the startup
signal and log the initialisation.

Signed-off-by: Daniel Silverstone <[email protected]>

Author: kinnison

src/application.rs

@@ -1,23 +1,49 @@
+use gio::ApplicationExt;
 use gio::ApplicationFlags;
 use glib;
+use glib::signal::SignalHandlerId;
 use glib::translate::*;
+use glib::ObjectExt;
 use gtk_sys;
 use rt;
 use Application;
 
+use std::cell::RefCell;
+use std::rc::Rc;
+
 impl Application {
+    pub(crate) fn register_startup_hook(app: &Application) {
+        skip_assert_initialized!();
+        let signalid: Rc<RefCell<Option<SignalHandlerId>>> = Rc::new(RefCell::new(None));
+        {
+            let signalid_ = signalid.clone();
+
+            let id = app.connect_startup(move |app| {
+                app.disconnect(
+                    signalid_
+                        .borrow_mut()
+                        .take()
+                        .expect("Signal ID went missing"),
+                );
+                unsafe { rt::set_initialized() }
+            });
+            *signalid.borrow_mut() = Some(id);
+        }
+    }
+
     pub fn new(
         application_id: Option<&str>,
         flags: ApplicationFlags,
     ) -> Result<Application, glib::BoolError> {
         skip_assert_initialized!();
-        try!(rt::init());
-        unsafe {
+        let app: Application = unsafe {
             Option::from_glib_full(gtk_sys::gtk_application_new(
                 application_id.to_glib_none().0,
                 flags.to_glib(),
             ))
-            .ok_or_else(|| glib_bool_error!("Failed to create application"))
-        }
+            .ok_or_else(|| glib_bool_error!("Failed to create application"))?
+        };
+        Application::register_startup_hook(&app);
+        Ok(app)
     }
 }