From fa2965d39a962de448f364ac3c07161c0ff64f53 Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Mon, 30 Mar 2020 20:23:40 +1000
Subject: [PATCH] add a temporary cache to bring deck list performance back

---
 pylib/anki/decks.py   | 10 ++++++++++
 pylib/anki/schedv2.py |  6 +++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/pylib/anki/decks.py b/pylib/anki/decks.py
index e86b69725..c2f16ad49 100644
--- a/pylib/anki/decks.py
+++ b/pylib/anki/decks.py
@@ -102,6 +102,7 @@ class DeckManager:
     def __init__(self, col: anki.storage._Collection) -> None:
         self.col = col.weakref()
         self.decks = {}
+        self._dconf_cache: Optional[Dict[int, Dict[str, Any]]] = None
 
     def load(self, decks: str, dconf: str) -> None:
         self.decks = json.loads(decks)
@@ -371,6 +372,8 @@ class DeckManager:
         return deck
 
     def getConf(self, confId: int) -> Any:
+        if self._dconf_cache is not None:
+            return self._dconf_cache.get(confId)
         return self.col.backend.get_deck_config(confId)
 
     def updateConf(self, g: Dict[str, Any]) -> None:
@@ -420,6 +423,13 @@ class DeckManager:
         if not oldOrder:
             self.col.sched.resortConf(new)
 
+    # temporary caching - don't use this as it will be removed
+    def _enable_dconf_cache(self):
+        self._dconf_cache = {c["id"]: c for c in self.allConf()}
+
+    def _disable_dconf_cache(self):
+        self._dconf_cache = None
+
     # Deck utils
     #############################################################
 
diff --git a/pylib/anki/schedv2.py b/pylib/anki/schedv2.py
index 07466ffd3..75ab8b5d0 100644
--- a/pylib/anki/schedv2.py
+++ b/pylib/anki/schedv2.py
@@ -270,7 +270,11 @@ order by due"""
         return data
 
     def deckDueTree(self) -> Any:
-        return self._groupChildren(self.deckDueList())
+        self.col.decks._enable_dconf_cache()
+        try:
+            return self._groupChildren(self.deckDueList())
+        finally:
+            self.col.decks._disable_dconf_cache()
 
     def _groupChildren(self, grps: List[List[Any]]) -> Any:
         # first, split the group names into components