Fix issue with display items model when changed from thread.

nion/swift/DataPanel.py

@@ -256,7 +256,7 @@ def audited_func() -> None:
 class ItemExplorerController:
     def __init__(self, ui: UserInterface.UserInterface,
                  canvas_item: CanvasItem.AbstractCanvasItem,
-                 display_item_adapters_model: ListModel.MappedListModel, selection: Selection.IndexedSelection,
+                 display_item_adapters_model: Panel.MappedListModelLike, selection: Selection.IndexedSelection,
                  direction: GridCanvasItem.Direction = GridCanvasItem.Direction.Row, wrap: bool = True) -> None:
         self.__pending_tasks: typing.List[asyncio.Task[None]] = list()
         self.ui = ui
@@ -317,7 +317,7 @@ def selection_changed() -> None:
         self.__selection_changed_listener: typing.Optional[Event.EventListener] = self.__selection.changed_event.listen(selection_changed)
         self.selected_indexes = list()
 
-        for index, display_item_adapter in enumerate(self.__display_item_adapters_model.display_item_adapters):
+        for index, display_item_adapter in enumerate(self.__display_item_adapters_model.items):
             self.__display_item_adapter_inserted("display_item_adapters", display_item_adapter, index)
 
         self.__closed = False
@@ -493,7 +493,7 @@ def drag_started(self, index: int, x: int, y: int, modifiers: UserInterface.Keyb
 
 
 class DataGridController(ItemExplorerController):
-    def __init__(self, ui: UserInterface.UserInterface, display_item_adapters_model: ListModel.MappedListModel,
+    def __init__(self, ui: UserInterface.UserInterface, display_item_adapters_model: Panel.MappedListModelLike,
                  selection: Selection.IndexedSelection,
                  direction: GridCanvasItem.Direction = GridCanvasItem.Direction.Row, wrap: bool = True) -> None:
         canvas_item = GridCanvasItem.GridCanvasItem(GridCanvasItemDelegate(self), selection, direction, wrap)
@@ -675,7 +675,7 @@ def unmap_display_item_to_display_item_adapter(display_item_adapter: DisplayItem
 
         display_items_model = document_controller.filtered_display_items_model
 
-        self.__filtered_display_item_adapters_model = ListModel.MappedListModel(container=display_items_model, master_items_key="display_items", items_key="display_item_adapters", map_fn=map_display_item_to_display_item_adapter, unmap_fn=unmap_display_item_to_display_item_adapter)
+        filtered_display_item_adapters_model = ListModel.MappedListModel(container=display_items_model, master_items_key="display_items", items_key="display_item_adapters", map_fn=map_display_item_to_display_item_adapter, unmap_fn=unmap_display_item_to_display_item_adapter)
 
         self.__selection = self.document_controller.selection
 
@@ -693,7 +693,7 @@ def focus_changed(focused: bool) -> None:
         def delete_display_item_adapters(display_item_adapters: typing.List[DisplayItemAdapter]) -> None:
             document_controller.delete_display_items([display_item_adapter.display_item for display_item_adapter in display_item_adapters if display_item_adapter.display_item])
 
-        self.data_grid_controller = DataGridController(ui, self.__filtered_display_item_adapters_model, self.__selection)
+        self.data_grid_controller = DataGridController(ui, Panel.ThreadSafeListModel(filtered_display_item_adapters_model, document_controller.event_loop), self.__selection)
         self.data_grid_controller.on_context_menu_event = show_context_menu
         self.data_grid_controller.on_focus_changed = focus_changed
         self.data_grid_controller.on_delete_display_item_adapters = delete_display_item_adapters
@@ -758,7 +758,7 @@ def _get_mime_data_and_thumbnail_data(self, drag_started_event: ListCanvasItem.L
                 return mime_data, thumbnail_data
 
         list_item_delegate = ListItemDelegate(self, self.__selection)
-        list_canvas_item = ListCanvasItem.ListCanvasItem2(display_items_model, self.__selection, list_item_factory, list_item_delegate, item_height=80, key="display_items")
+        list_canvas_item = ListCanvasItem.ListCanvasItem2(Panel.ThreadSafeListModel(display_items_model, document_controller.event_loop), self.__selection, list_item_factory, list_item_delegate, item_height=80, key="display_items")
         scroll_area_canvas_item = CanvasItem.ScrollAreaCanvasItem(list_canvas_item)
         scroll_bar_canvas_item = CanvasItem.ScrollBarCanvasItem(scroll_area_canvas_item, CanvasItem.Orientation.Vertical)
         scroll_group_canvas_item = CanvasItem.CanvasItemComposition()
@@ -873,8 +873,6 @@ def close(self) -> None:
         # finish closing
         self.data_grid_controller.close()
         self.data_grid_controller = typing.cast(DataGridController, None)
-        self.__filtered_display_item_adapters_model.close()
-        self.__filtered_display_item_adapters_model = typing.cast(ListModel.MappedListModel, None)
         # button group
         self.__view_button_group.close()
         self.__view_button_group = typing.cast(CanvasItem.RadioButtonGroup, None)

nion/swift/FilterPanel.py

@@ -99,7 +99,7 @@ def display_item_removed(key: str, display_item: _ValueType, index: int) -> None
         # connect the display_items_model from the document controller to self.
         # when data items are inserted or removed from the document controller, the inserter and remover methods
         # will be called.
-        self.__display_items_model = document_controller.display_items_model
+        self.__display_items_model = Panel.ThreadSafeListModel(document_controller.display_items_model, document_controller.event_loop)
 
         self.__display_item_inserted_listener = self.__display_items_model.item_inserted_event.listen(display_item_inserted)
         self.__display_item_removed_listener = self.__display_items_model.item_removed_event.listen(display_item_removed)
@@ -111,7 +111,7 @@ def display_item_removed(key: str, display_item: _ValueType, index: int) -> None
         self.__date_filter: typing.Optional[ListModel.Filter] = None
         self.__text_filter: typing.Optional[ListModel.Filter] = None
 
-        for index, display_item in enumerate(self.__display_items_model.display_items):
+        for index, display_item in enumerate(self.__display_items_model.items):
             display_item_inserted("display_items", display_item, index)
 
     def close(self) -> None:

nion/swift/Panel.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 # standard libraries
+import asyncio
 import collections
 import dataclasses
 import functools
@@ -20,7 +21,9 @@
 from nion.ui import CanvasItem
 from nion.ui import Declarative
 from nion.ui import UserInterface
+from nion.utils import Event
 from nion.utils import Geometry
+from nion.utils import ReferenceCounting
 from nion.utils import Registry
 
 if typing.TYPE_CHECKING:
@@ -607,3 +610,51 @@ def is_panel_section_valid(self, panel_section_id: str) -> bool:
             if panel_section_id in panel_section_factory.panel_section_ids:
                 return True
         return False
+
+
+# useful utility class
+
+class MappedListModelLike(typing.Protocol):
+    item_inserted_event: Event.Event
+    item_removed_event: Event.Event
+    end_changes_event: Event.Event
+
+    @property
+    def items(self) -> typing.Sequence[typing.Any]:
+        raise NotImplementedError()
+
+
+class ThreadSafeListModel(MappedListModelLike):
+    def __init__(self, list_model: MappedListModelLike, event_loop: asyncio.AbstractEventLoop) -> None:
+        self.__items = list(list_model.items)
+        self.__event_loop = event_loop
+
+        self.__list_model = list_model
+        self.item_inserted_event = Event.Event()
+        self.item_removed_event = Event.Event()
+        self.end_changes_event = Event.Event()
+
+        self.__item_inserted_listener = self.__list_model.item_inserted_event.listen(ReferenceCounting.weak_partial(ThreadSafeListModel.__list_model_item_inserted, self))
+        self.__item_removed_listener = self.__list_model.item_removed_event.listen(ReferenceCounting.weak_partial(ThreadSafeListModel.__list_model_item_removed, self))
+        self.__end_changes_listener = self.__list_model.end_changes_event.listen(ReferenceCounting.weak_partial(ThreadSafeListModel.__end_changes, self))
+
+    def __list_model_item_inserted(self, key: str, item: typing.Any, before_index: int) -> None:
+        if threading.current_thread() != threading.main_thread():
+            self.__event_loop.call_soon_threadsafe(self.__list_model_item_inserted, key, item, before_index)
+        else:
+            self.__items.insert(before_index, item)
+            self.item_inserted_event.fire(key, item, before_index)
+
+    def __list_model_item_removed(self, key: str, item: typing.Any, index: int) -> None:
+        if threading.current_thread() != threading.main_thread():
+            self.__event_loop.call_soon_threadsafe(self.__list_model_item_removed, key, item, index)
+        else:
+            del self.__items[index]
+            self.item_removed_event.fire(key, item, index)
+
+    def __end_changes(self, key: str) -> None:
+        self.end_changes_event.fire(key)
+
+    @property
+    def items(self) -> typing.Sequence[typing.Any]:
+        return list(self.__items)