Python: Add support for invoke_from_event_loop

Fixes #420

api/python/lib.rs

@@ -20,6 +20,18 @@ fn quit_event_loop() -> Result<(), errors::PyEventLoopError> {
  slint_interpreter::quit_event_loop().map_err(|e| e.into())
 }
 
+#[pyfunction]
+fn invoke_from_event_loop(callable: PyObject) -> Result<(), errors::PyEventLoopError> {
+ slint_interpreter::invoke_from_event_loop(move || {
+ Python::with_gil(|py| {
+ if let Err(err) = callable.call0(py) {
+ eprintln!("Error invoking python callable from closure invoked via slint::invoke_from_event_loop: {}", err)
+ } 
+ })
+ })
+ .map_err(|e| e.into())
+}
+
 use pyo3::prelude::*;
 
 #[pymodule]
@@ -42,6 +54,7 @@ fn slint(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
  m.add_class::<models::PyModelBase>()?;
  m.add_function(wrap_pyfunction!(run_event_loop, m)?)?;
  m.add_function(wrap_pyfunction!(quit_event_loop, m)?)?;
+ m.add_function(wrap_pyfunction!(invoke_from_event_loop, m)?)?;
 
  Ok(())
 }

api/python/tests/test_invoke_from_event_loop.py

@@ -0,0 +1,29 @@
+# Copyright © SixtyFPS GmbH <[email protected]>
+# SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-1.1 OR LicenseRef-Slint-commercial
+
+from slint import slint as native
+import threading
+from datetime import timedelta
+
+
+def test_threads():
+ global was_here
+ was_here = False
+
+ def invoked_from_event_loop():
+ global was_here
+ was_here = True
+ native.quit_event_loop()
+
+ def quit():
+ native.invoke_from_event_loop(invoked_from_event_loop)
+
+ thr = threading.Thread(target=quit)
+ native.Timer.single_shot(timedelta(milliseconds=10), lambda: thr.start())
+ fallback_timer = native.Timer()
+ fallback_timer.start(native.TimerMode.Repeated, timedelta(
+ milliseconds=100), native.quit_event_loop)
+ native.run_event_loop()
+ thr.join()
+ fallback_timer.stop()
+ assert was_here == True