Locally, transactions

src/table.rs

@@ -76,7 +76,7 @@ pub trait Entry<P: PartitionKey, S: SortKey>: Clone + Serialize + for<'de> Deser
 	fn partition_key(&self) -> &P;
 	fn sort_key(&self) -> &S;
 
-	fn merge(&mut self, other: &Self);
+	fn merge(&mut self, other: &Self) -> bool;
 }
 
 #[derive(Clone, Serialize, Deserialize)]
@@ -152,13 +152,17 @@ impl<F: TableFormat + 'static> Table<F> {
 			.await?;
 
 		let mut ret = None;
+		let mut not_all_same = false;
 		for resp in resps {
 			if let TableRPC::ReadEntryResponse(value) = resp {
 				if let Some(v) = value {
 					ret = match ret {
 						None => Some(v),
 						Some(mut x) => {
-							x.merge(&v);
+							let updated = x.merge(&v);
+							if updated {
+								not_all_same = true;
+							}
 							Some(x)
 						}
 					}
@@ -167,6 +171,16 @@ impl<F: TableFormat + 'static> Table<F> {
 				return Err(Error::Message(format!("Invalid return value to read")));
 			}
 		}
+		if let Some(ret_entry) = &ret {
+			if not_all_same {
+				// Repair on read
+				let _: Result<_, _> = self.rpc_try_call_many(
+						&who[..],
+						&TableRPC::<F>::Update(vec![ret_entry.clone()]),
+						who.len())
+					.await;
+			}
+		}
 		Ok(ret)
 	}
 
@@ -221,22 +235,31 @@ impl<F: TableFormat + 'static> Table<F> {
 	}
 
 	async fn handle_update(&self, mut entries: Vec<F::E>) -> Result<(), Error> {
-		for mut entry in entries.drain(..) {
-			let tree_key = self.tree_key(entry.partition_key(), entry.sort_key());
+		for update in entries.drain(..) {
+			let tree_key = self.tree_key(update.partition_key(), update.sort_key());
 
-			let old_val = match self.store.get(&tree_key)? {
-				Some(prev_bytes) => {
-					let old_entry = rmp_serde::decode::from_read_ref::<_, F::E>(&prev_bytes)?;
-					entry.merge(&old_entry);
-					Some(old_entry)
-				}
-				None => None
-			};
+			let (old_entry, new_entry) = self.store.transaction(|db| {
+				let mut new_entry = update.clone();
 
-			let new_bytes = rmp_to_vec_all_named(&entry)?;
-			self.store.insert(&tree_key, new_bytes)?;
+				let old_entry = match db.get(&tree_key)? {
+					Some(prev_bytes) => {
+						let old_entry = rmp_serde::decode::from_read_ref::<_, F::E>(&prev_bytes)
+							.map_err(Error::RMPDecode)
+							.map_err(sled::ConflictableTransactionError::Abort)?;
+						new_entry.merge(&old_entry);
+						Some(old_entry)
+					}
+					None => None
+				};
 
-			self.instance.updated(old_val.as_ref(), &entry).await;
+				let new_bytes = rmp_to_vec_all_named(&new_entry)
+					.map_err(Error::RMPEncode)
+					.map_err(sled::ConflictableTransactionError::Abort)?;
+				db.insert(tree_key.clone(), new_bytes)?;
+				Ok((old_entry, new_entry))
+			})?;
+
+			self.instance.updated(old_entry.as_ref(), &new_entry).await;
 		}
 		Ok(())
 	}