Add locking to some UI actions.

This is by no means complete. The bugs that this solves were already in
6.x, but we'd hidden the speed controls for the sim in that release, and
have always said that anything done after pressing "go" the first time
is undefined behavior. This is the first step on making those mid-sim
actions behave correctly.

UI actions such as creating a new package need to be executed between
ticks of the sim. We can either do this synchronously by blocking the UI
until the tick is done executing, acquiring a lock on the sim, executing
the action, then releasing the lock; or asynchronously by queueing
events and letting the sim execute them when it completes the current
tick (or instantly if the sim is paused).

Anything that comes from the new UI (currently just the map) must be
asynchronous because it goes through the REST API, but for the old UI
it's simpler (and because the lock will only be acquired as quickly as
the user can act, shouldn't slow anything down) to do this
synchronously, since it's difficult to use coroutines in Qt.

https://github.com/dcs-liberation/dcs_liberation/issues/1680

qt_ui/models.py

@@ -158,54 +158,60 @@ class PackageModel(QAbstractListModel):
 
     def add_flight(self, flight: Flight) -> None:
         """Adds the given flight to the package."""
-        self.beginInsertRows(QModelIndex(), self.rowCount(), self.rowCount())
-        self.package.add_flight(flight)
-        # update_tot is not called here because the new flight does not have a
-        # flight plan yet. Will be called manually by the caller.
-        self.endInsertRows()
+        with self.game_model.sim_controller.paused_sim():
+            self.beginInsertRows(QModelIndex(), self.rowCount(), self.rowCount())
+            self.package.add_flight(flight)
+            # update_tot is not called here because the new flight does not have a
+            # flight plan yet. Will be called manually by the caller.
+            self.endInsertRows()
 
     def cancel_or_abort_flight_at_index(self, index: QModelIndex) -> None:
         """Removes the flight at the given index from the package."""
         self.cancel_or_abort_flight(self.flight_at_index(index))
 
     def cancel_or_abort_flight(self, flight: Flight) -> None:
-        if flight.state.cancelable:
-            self.delete_flight(flight)
-            EventStream.put_nowait(GameUpdateEvents().delete_flight(flight))
-        else:
-            flight.abort()
-            EventStream.put_nowait(GameUpdateEvents().update_flight(flight))
+        with self.game_model.sim_controller.paused_sim():
+            if flight.state.cancelable:
+                self.delete_flight(flight)
+                EventStream.put_nowait(GameUpdateEvents().delete_flight(flight))
+            else:
+                flight.abort()
+                EventStream.put_nowait(GameUpdateEvents().update_flight(flight))
 
     def delete_flight(self, flight: Flight) -> None:
         """Removes the given flight from the package."""
-        index = self.package.flights.index(flight)
-        self.beginRemoveRows(QModelIndex(), index, index)
-        self.package.remove_flight(flight)
-        self.endRemoveRows()
-        self.update_tot()
-        self.game_model.release_freq(flight.frequency)
-        self.game_model.release_tacan(flight.tacan)
+        with self.game_model.sim_controller.paused_sim():
+            index = self.package.flights.index(flight)
+            self.beginRemoveRows(QModelIndex(), index, index)
+            self.package.remove_flight(flight)
+            self.endRemoveRows()
+            self.update_tot()
+            self.game_model.release_freq(flight.frequency)
+            self.game_model.release_tacan(flight.tacan)
 
     def flight_at_index(self, index: QModelIndex) -> Flight:
         """Returns the flight located at the given index."""
         return self.package.flights[index.row()]
 
     def set_tot(self, tot: datetime.datetime) -> None:
-        self.package.time_over_target = tot
-        self.update_tot()
+        with self.game_model.sim_controller.paused_sim():
+            self.package.time_over_target = tot
+            self.update_tot()
 
     def set_asap(self, asap: bool) -> None:
-        self.package.auto_asap = asap
-        self.update_tot()
+        with self.game_model.sim_controller.paused_sim():
+            self.package.auto_asap = asap
+            self.update_tot()
 
     def update_tot(self) -> None:
-        if self.package.auto_asap:
-            self.package.set_tot_asap(
-                self.game_model.sim_controller.current_time_in_sim
-            )
-        self.tot_changed.emit()
-        # For some reason this is needed to make the UI update quickly.
-        self.layoutChanged.emit()
+        with self.game_model.sim_controller.paused_sim():
+            if self.package.auto_asap:
+                self.package.set_tot_asap(
+                    self.game_model.sim_controller.current_time_in_sim
+                )
+            self.tot_changed.emit()
+            # For some reason this is needed to make the UI update quickly.
+            self.layoutChanged.emit()
 
     @property
     def mission_target(self) -> MissionTarget:
@@ -263,34 +269,36 @@ class AtoModel(QAbstractListModel):
 
     def add_package(self, package: Package) -> None:
         """Adds a package to the ATO."""
-        self.beginInsertRows(QModelIndex(), self.rowCount(), self.rowCount())
-        self.ato.add_package(package)
-        # We do not need to send events for new flights in the package here. Events were
-        # already sent when the flights were added to the in-progress package.
-        self.endInsertRows()
-        # noinspection PyUnresolvedReferences
-        self.client_slots_changed.emit()
-        self.on_packages_changed()
+        with self.game_model.sim_controller.paused_sim():
+            self.beginInsertRows(QModelIndex(), self.rowCount(), self.rowCount())
+            self.ato.add_package(package)
+            # We do not need to send events for new flights in the package here. Events
+            # were already sent when the flights were added to the in-progress package.
+            self.endInsertRows()
+            # noinspection PyUnresolvedReferences
+            self.client_slots_changed.emit()
+            self.on_packages_changed()
 
     def cancel_or_abort_package_at_index(self, index: QModelIndex) -> None:
         """Removes the package at the given index from the ATO."""
         self.cancel_or_abort_package(self.package_at_index(index))
 
     def cancel_or_abort_package(self, package: Package) -> None:
-        with EventStream.event_context() as events:
-            if all(f.state.cancelable for f in package.flights):
-                events.delete_flights_in_package(package)
-                self._delete_package(package)
-                return
+        with self.game_model.sim_controller.paused_sim():
+            with EventStream.event_context() as events:
+                if all(f.state.cancelable for f in package.flights):
+                    events.delete_flights_in_package(package)
+                    self._delete_package(package)
+                    return
 
-            package_model = self.find_matching_package_model(package)
-            for flight in package.flights:
-                if flight.state.cancelable:
-                    package_model.delete_flight(flight)
-                    events.delete_flight(flight)
-                else:
-                    flight.abort()
-                    events.update_flight(flight)
+                package_model = self.find_matching_package_model(package)
+                for flight in package.flights:
+                    if flight.state.cancelable:
+                        package_model.delete_flight(flight)
+                        events.delete_flight(flight)
+                    else:
+                        flight.abort()
+                        events.update_flight(flight)
 
     def _delete_package(self, package: Package) -> None:
         """Removes the given package from the ATO."""

qt_ui/simcontroller.py

@@ -1,6 +1,8 @@
 from __future__ import annotations
 
 import logging
+from collections.abc import Iterator
+from contextlib import contextmanager
 from datetime import datetime, timedelta
 from pathlib import Path
 from typing import Callable, Optional, TYPE_CHECKING
@@ -76,6 +78,11 @@ class SimController(QObject):
             self.started = True
         self.game_loop.set_simulation_speed(simulation_speed)
 
+    @contextmanager
+    def paused_sim(self) -> Iterator[None]:
+        with self.game_loop.paused_sim():
+            yield
+
     def run_to_first_contact(self) -> None:
         self.game_loop.run_to_first_contact()