speed up browser load by rendering deck tree in Rust and skipping counts

proto/backend.proto

@@ -30,7 +30,7 @@ message I18nBackendInit {
 message BackendInput {
     oneof value {
         SchedTimingTodayIn sched_timing_today = 17;
-        Empty deck_tree = 18;
+        DeckTreeIn deck_tree = 18;
         SearchCardsIn search_cards = 19;
         SearchNotesIn search_notes = 20;
         RenderCardIn render_card = 21;
@@ -108,7 +108,7 @@ message BackendOutput {
         AllStockNotetypesOut all_stock_notetypes = 60;
 
         // fallible commands
-        DeckTreeOut deck_tree = 18;
+        DeckTreeNode deck_tree = 18;
         SearchCardsOut search_cards = 19;
         SearchNotesOut search_notes = 20;
         RenderCardOut render_card = 21;
@@ -238,19 +238,20 @@ message SchedTimingTodayOut {
     int64 next_day_at = 2;
 }
 
-message DeckTreeOut {
-    DeckTreeNode top = 1;
+message DeckTreeIn {
+    bool include_counts = 1;
 }
 
 message DeckTreeNode {
-    // the components of a deck, split on ::
-    repeated string names = 1;
-    int64 deck_id = 2;
-    uint32 review_count = 3;
-    uint32 learn_count = 4;
-    uint32 new_count = 5;
-    repeated DeckTreeNode children = 6;
-    bool collapsed = 7;
+    int64 deck_id = 1;
+    string name = 2;
+    repeated DeckTreeNode children = 3;
+    uint32 level = 4;
+    bool collapsed = 5;
+
+    uint32 review_count = 6;
+    uint32 learn_count = 7;
+    uint32 new_count = 8;
 }
 
 message RenderCardIn {
@@ -705,3 +706,4 @@ message AddOrUpdateDeckLegacyIn {
     bytes deck = 1;
     bool preserve_usn_and_mtime = 2;
 }
+

pylib/anki/decks.py

@@ -219,6 +219,9 @@ class DeckManager:
         except anki.rsbackend.ExistsError:
             raise DeckRenameError("deck already exists")
 
+    def deck_tree(self) -> pb.DeckTreeNode:
+        return self.col.backend.deck_tree(include_counts=False)
+
     def all(self, force_default: bool = True) -> List:
         """A list of all decks.
 

pylib/anki/rsbackend.py

@@ -49,6 +49,7 @@ BackendCard = pb.Card
 BackendNote = pb.Note
 TagUsnTuple = pb.TagUsnTuple
 NoteType = pb.NoteType
+DeckTreeNode = pb.DeckTreeNode
 
 try:
     import orjson
@@ -729,6 +730,11 @@ class RustBackend:
     def remove_deck(self, did: int) -> None:
         self._run_command(pb.BackendInput(remove_deck=did))
 
+    def deck_tree(self, include_counts: bool) -> DeckTreeNode:
+        return self._run_command(
+            pb.BackendInput(deck_tree=pb.DeckTreeIn(include_counts=include_counts))
+        ).deck_tree
+
 
 def translate_string_in(
     key: TR, **kwargs: Union[str, int, float]

qt/aqt/browser.py

@@ -24,7 +24,7 @@ from anki.decks import DeckManager
 from anki.lang import _, ngettext
 from anki.models import NoteType
 from anki.notes import Note
-from anki.rsbackend import TR
+from anki.rsbackend import TR, DeckTreeNode
 from anki.utils import htmlToTextLine, ids2str, intTime, isMac, isWin
 from aqt import AnkiQt, gui_hooks
 from aqt.editor import Editor
@@ -1147,32 +1147,28 @@ QTableView {{ gridline-color: {grid} }}
             root.addChild(item)
 
     def _decksTree(self, root) -> None:
-        assert self.col
-        grps = self.col.sched.deckDueTree()
+        tree = self.col.decks.deck_tree()
 
-        def fillGroups(root, grps, head=""):
-            for g in grps:
-                baseName = g[0]
-                did = g[1]
-                children = g[5]
-                if str(did) == "1" and not children:
+        def fillGroups(root, nodes: List[DeckTreeNode], head=""):
+            for node in nodes:
+                if node.deck_id == 1 and not node.children:
                     if not self.mw.col.decks.should_default_be_displayed(
                         force_default=False, assume_no_child=True
                     ):
-
                         continue
+
                 item = SidebarItem(
-                    baseName,
+                    node.name,
                     ":/icons/deck.svg",
-                    lambda baseName=baseName: self.setFilter("deck", head + baseName),
-                    lambda expanded, did=did: self.mw.col.decks.collapseBrowser(did),
-                    not self.mw.col.decks.get(did).get("browserCollapsed", False),
+                    lambda baseName=node.name: self.setFilter("deck", head + baseName),
+                    lambda expanded, did=node.deck_id: self.mw.col.decks.collapseBrowser(did),
+                    not self.mw.col.decks.get(node.deck_id).get("browserCollapsed", False),
                 )
                 root.addChild(item)
-                newhead = head + baseName + "::"
-                fillGroups(item, children, newhead)
+                newhead = head + node.name + "::"
+                fillGroups(item, node.children, newhead)
 
-        fillGroups(root, grps)
+        fillGroups(root, tree.children)
 
     def _modelTree(self, root) -> None:
         assert self.col

rslib/src/backend/mod.rs

@@ -217,7 +217,7 @@ impl Backend {
             Value::SchedTimingToday(input) => {
                 OValue::SchedTimingToday(self.sched_timing_today(input))
             }
-            Value::DeckTree(_) => todo!(),
+            Value::DeckTree(input) => OValue::DeckTree(self.deck_tree(input)?),
             Value::RenderCard(input) => OValue::RenderCard(self.render_template(input)?),
             Value::LocalMinutesWest(stamp) => {
                 OValue::LocalMinutesWest(local_minutes_west_for_stamp(stamp))
@@ -436,6 +436,16 @@ impl Backend {
         }
     }
 
+    fn deck_tree(&self, input: pb::DeckTreeIn) -> Result<pb::DeckTreeNode> {
+        self.with_col(|col| {
+            if input.include_counts {
+                todo!()
+            } else {
+                col.deck_tree()
+            }
+        })
+    }
+
     fn render_template(&self, input: pb::RenderCardIn) -> Result<pb::RenderCardOut> {
         // convert string map to &str
         let fields: HashMap<_, _> = input

rslib/src/decks/mod.rs

@@ -16,6 +16,7 @@ use crate::{
     types::Usn,
 };
 mod schema11;
+mod tree;
 pub use schema11::DeckSchema11;
 use std::{borrow::Cow, sync::Arc};
 

rslib/src/decks/tree.rs

@@ -0,0 +1,105 @@
+// Copyright: Ankitects Pty Ltd and contributors
+// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
+
+use crate::{backend_proto::DeckTreeNode, collection::Collection, decks::DeckID, err::Result};
+use std::iter::Peekable;
+
+// fixme: handle mixed case of parents
+
+fn deck_names_to_tree(names: Vec<(DeckID, String)>) -> DeckTreeNode {
+    let mut top = DeckTreeNode::default();
+    let mut it = names.into_iter().peekable();
+
+    add_child_nodes(&mut it, &mut top);
+
+    top
+}
+
+fn add_child_nodes(
+    names: &mut Peekable<impl Iterator<Item = (DeckID, String)>>,
+    parent: &mut DeckTreeNode,
+) {
+    while let Some((id, name)) = names.peek() {
+        let split_name: Vec<_> = name.split("::").collect();
+        match split_name.len() as u32 {
+            l if l <= parent.level => {
+                // next item is at a higher level
+                return;
+            }
+            l if l == parent.level + 1 => {
+                // next item is an immediate descendent of parent
+                parent.children.push(DeckTreeNode {
+                    deck_id: id.0,
+                    name: (*split_name.last().unwrap()).into(),
+                    children: vec![],
+                    level: parent.level + 1,
+                    ..Default::default()
+                });
+                names.next();
+            }
+            _ => {
+                // next item is at a lower level
+                if let Some(last_child) = parent.children.last_mut() {
+                    add_child_nodes(names, last_child)
+                } else {
+                    // immediate parent is missing, skip the deck until a DB check is run
+                    names.next();
+                }
+            }
+        }
+    }
+}
+
+impl Collection {
+    pub fn deck_tree(&self) -> Result<DeckTreeNode> {
+        let names = self.storage.get_all_deck_names()?;
+        Ok(deck_names_to_tree(names))
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::{collection::open_test_collection, err::Result};
+
+    #[test]
+    fn wellformed() -> Result<()> {
+        let mut col = open_test_collection();
+
+        col.get_or_create_normal_deck("1")?;
+        col.get_or_create_normal_deck("2")?;
+        col.get_or_create_normal_deck("2::a")?;
+        col.get_or_create_normal_deck("2::b")?;
+        col.get_or_create_normal_deck("2::c")?;
+        col.get_or_create_normal_deck("2::c::A")?;
+        col.get_or_create_normal_deck("3")?;
+
+        let tree = col.deck_tree()?;
+
+        // 4 including default
+        assert_eq!(tree.children.len(), 4);
+
+        assert_eq!(tree.children[1].name, "2");
+        assert_eq!(tree.children[1].children[0].name, "a");
+        assert_eq!(tree.children[1].children[2].name, "c");
+        assert_eq!(tree.children[1].children[2].children[0].name, "A");
+
+        Ok(())
+    }
+
+    #[test]
+    fn malformed() -> Result<()> {
+        let mut col = open_test_collection();
+
+        col.get_or_create_normal_deck("1")?;
+        col.get_or_create_normal_deck("2::3::4")?;
+
+        // remove the top parent and middle parent
+        col.storage.remove_deck(col.get_deck_id("2")?.unwrap())?;
+        col.storage.remove_deck(col.get_deck_id("2::3")?.unwrap())?;
+
+        let tree = col.deck_tree()?;
+        assert_eq!(tree.children.len(), 2);
+
+        Ok(())
+    }
+}