Ensure deck browser fetches collection data in the background

qt/aqt/deckbrowser.py

@@ -10,7 +10,7 @@ from typing import Any
 
 import aqt
 import aqt.operations
-from anki.collection import OpChanges
+from anki.collection import Collection, OpChanges
 from anki.decks import DeckCollapseScope, DeckId, DeckTreeNode
 from aqt import AnkiQt, gui_hooks
 from aqt.deckoptions import display_options_for_deck_id
@@ -34,6 +34,16 @@ class DeckBrowserBottomBar:
         self.deck_browser = deck_browser
 
 
+@dataclass
+class RenderData:
+    """Data from collection that is required to show the page."""
+
+    tree: DeckTreeNode
+    current_deck_id: DeckId
+    studied_today: str
+    sched_upgrade_required: bool
+
+
 @dataclass
 class DeckBrowserContent:
     """Stores sections of HTML content that the deck browser will be
@@ -54,7 +64,7 @@ class RenderDeckNodeContext:
 
 
 class DeckBrowser:
-    _dueTree: DeckTreeNode
+    _render_data: RenderData
 
     def __init__(self, mw: AnkiQt) -> None:
         self.mw = mw
@@ -147,27 +157,36 @@ class DeckBrowser:
     def _renderPage(self, reuse: bool = False) -> None:
         if not reuse:
 
-            def success(tree: DeckTreeNode) -> None:
-                self._dueTree = tree
+            def get_data(col: Collection) -> RenderData:
+                return RenderData(
+                    tree=col.sched.deck_due_tree(),
+                    current_deck_id=col.decks.get_current_id(),
+                    studied_today=col.studied_today(),
+                    sched_upgrade_required=not col.v3_scheduler(),
+                )
+
+            def success(output: RenderData) -> None:
+                self._render_data = output
                 self.__renderPage(None)
-                return
 
             QueryOp(
                 parent=self.mw,
-                op=lambda col: col.sched.deck_due_tree(),
+                op=get_data,
                 success=success,
             ).run_in_background()
         else:
             self.web.evalWithCallback("window.pageYOffset", self.__renderPage)
 
     def __renderPage(self, offset: int | None) -> None:
+        data = self._render_data
         content = DeckBrowserContent(
-            tree=self._renderDeckTree(self._dueTree),
-            stats=self._renderStats(),
+            tree=self._renderDeckTree(data.tree),
+            stats=self._renderStats(data.studied_today),
         )
         gui_hooks.deck_browser_will_render_content(self, content)
         self.web.stdHtml(
-            self._v1_upgrade_message() + self._body % content.__dict__,
+            self._v1_upgrade_message(data.sched_upgrade_required)
+            + self._body % content.__dict__,
             css=["css/deckbrowser.css"],
             js=[
                 "js/vendor/jquery.min.js",
@@ -184,10 +203,8 @@ class DeckBrowser:
     def _scrollToOffset(self, offset: int) -> None:
         self.web.eval("window.scrollTo(0, %d, 'instant');" % offset)
 
-    def _renderStats(self) -> str:
-        return '<div id="studiedToday"><span>{}</span></div>'.format(
-            self.mw.col.studied_today(),
-        )
+    def _renderStats(self, today: str) -> str:
+        return '<div id="studiedToday"><span>{}</span></div>'.format(today)
 
     def _renderDeckTree(self, top: DeckTreeNode) -> str:
         buf = """
@@ -203,7 +220,7 @@ class DeckBrowser:
         )
         buf += self._topLevelDragRow()
 
-        ctx = RenderDeckNodeContext(current_deck_id=self.mw.col.conf["curDeck"])
+        ctx = RenderDeckNodeContext(current_deck_id=self._render_data.current_deck_id)
 
         for child in top.children:
             buf += self._render_deck_node(child, ctx)
@@ -320,7 +337,7 @@ class DeckBrowser:
         display_options_for_deck_id(did)
 
     def _collapse(self, did: DeckId) -> None:
-        node = self.mw.col.decks.find_deck_in_tree(self._dueTree, did)
+        node = self.mw.col.decks.find_deck_in_tree(self._render_data.tree, did)
         if node:
             node.collapsed = not node.collapsed
             set_deck_collapsed(
@@ -375,8 +392,8 @@ class DeckBrowser:
 
     ######################################################################
 
-    def _v1_upgrade_message(self) -> str:
-        if self.mw.col.sched_ver() == 2 and self.mw.col.v3_scheduler():
+    def _v1_upgrade_message(self, required: bool) -> str:
+        if not required:
             return ""
 
         update_required = tr.scheduling_update_required().replace("V2", "v3")