support updating multiple cards in one transaction/undo op

proto/anki/cards.proto

@@ -10,7 +10,7 @@ import "anki/collection.proto";
 
 service CardsService {
   rpc GetCard(CardId) returns (Card);
-  rpc UpdateCard(UpdateCardRequest) returns (collection.OpChanges);
+  rpc UpdateCards(UpdateCardsRequest) returns (collection.OpChanges);
   rpc RemoveCards(RemoveCardsRequest) returns (generic.Empty);
   rpc SetDeck(SetDeckRequest) returns (collection.OpChangesWithCount);
   rpc SetFlag(SetFlagRequest) returns (collection.OpChangesWithCount);
@@ -44,8 +44,8 @@ message Card {
   string data = 18;
 }
 
-message UpdateCardRequest {
+message UpdateCardsRequest {
-  Card card = 1;
+  repeated Card cards = 1;
   bool skip_undo_entry = 2;
 }
 

pylib/anki/cards.py

@@ -114,8 +114,8 @@ class Card(DeprecatedNamesMixin):
     def flush(self) -> None:
         hooks.card_will_flush(self)
         if self.id != 0:
-            self.col._backend.update_card(
+            self.col._backend.update_cards(
-                card=self._to_backend_card(), skip_undo_entry=True
+                cards=[self._to_backend_card()], skip_undo_entry=True
             )
         else:
             raise Exception("card.flush() expects an existing card")

pylib/anki/collection.py

@@ -314,10 +314,17 @@ class Collection(DeprecatedNamesMixin):
     def get_card(self, id: CardId) -> Card:
         return Card(self, id)
 
-    def update_card(self, card: Card) -> None:
+    def update_cards(self, cards: Sequence[Card]) -> OpChanges:
         """Save card changes to database, and add an undo entry.
         Unlike card.flush(), this will invalidate any current checkpoint."""
-        self._backend.update_card(card=card._to_backend_card(), skip_undo_entry=False)
+        return self._backend.update_cards(
+            cards=[c._to_backend_card() for c in cards], skip_undo_entry=False
+        )
+
+    def update_card(self, card: Card) -> OpChanges:
+        """Save card changes to database, and add an undo entry.
+        Unlike card.flush(), this will invalidate any current checkpoint."""
+        return self.update_cards([card])
 
     def get_note(self, id: NoteId) -> Note:
         return Note(self, id=id)

rslib/src/backend/card.rs

@@ -21,10 +21,14 @@ impl CardsService for Backend {
         })
     }
 
-    fn update_card(&self, input: pb::UpdateCardRequest) -> Result<pb::OpChanges> {
+    fn update_cards(&self, input: pb::UpdateCardsRequest) -> Result<pb::OpChanges> {
         self.with_col(|col| {
-            let mut card: Card = input.card.ok_or(AnkiError::NotFound)?.try_into()?;
+            let cards = input
-            col.update_card_maybe_undoable(&mut card, !input.skip_undo_entry)
+                .cards
+                .into_iter()
+                .map(TryInto::try_into)
+                .collect::<Result<Vec<Card>, AnkiError>>()?;
+            col.update_cards_maybe_undoable(cards, !input.skip_undo_entry)
         })
         .map(Into::into)
     }

rslib/src/card/mod.rs

@@ -159,19 +159,25 @@ impl Card {
 }
 
 impl Collection {
-    pub(crate) fn update_card_maybe_undoable(
+    pub(crate) fn update_cards_maybe_undoable(
         &mut self,
-        card: &mut Card,
+        cards: Vec<Card>,
         undoable: bool,
     ) -> Result<OpOutput<()>> {
-        let existing = self.storage.get_card(card.id)?.ok_or(AnkiError::NotFound)?;
         if undoable {
             self.transact(Op::UpdateCard, |col| {
-                col.update_card_inner(card, existing, col.usn()?)
+                for mut card in cards {
+                    let existing = col.storage.get_card(card.id)?.ok_or(AnkiError::NotFound)?;
+                    col.update_card_inner(&mut card, existing, col.usn()?)?
+                }
+                Ok(())
             })
         } else {
             self.transact_no_undo(|col| {
-                col.update_card_inner(card, existing, col.usn()?)?;
+                for mut card in cards {
+                    let existing = col.storage.get_card(card.id)?.ok_or(AnkiError::NotFound)?;
+                    col.update_card_inner(&mut card, existing, col.usn()?)?;
+                }
                 Ok(OpOutput {
                     output: (),
                     changes: OpChanges {