From a3b39ee42c3a0d3df6f6a3b55a57160759d43df3 Mon Sep 17 00:00:00 2001
From: projectmoon <projectmoon@agnos.is>
Date: Wed, 19 May 2021 21:34:11 +0000
Subject: [PATCH] Use ON CONFLICT and transactions where appropriate.

---
 src/db/sqlite/rooms.rs | 50 ++++++++++++++++++++----------------------
 1 file changed, 24 insertions(+), 26 deletions(-)

diff --git a/src/db/sqlite/rooms.rs b/src/db/sqlite/rooms.rs
index 9e89850..14e8ce4 100644
--- a/src/db/sqlite/rooms.rs
+++ b/src/db/sqlite/rooms.rs
@@ -51,18 +51,15 @@ impl Rooms for Database {
     }
 
     async fn insert_room_info(&self, info: &RoomInfo) -> Result<(), DataError> {
-        //Clear out old info first, because we want this to be an "upsert."
-        sqlx::query("DELETE FROM room_info where room_id = ?")
-            .bind(&info.room_id)
-            .execute(&self.conn)
-            .await
-            .ok();
-
-        sqlx::query(r#"INSERT INTO room_info (room_id, room_name) VALUES (?, ?)"#)
-            .bind(&info.room_id)
-            .bind(&info.room_name)
-            .execute(&self.conn)
-            .await?;
+        sqlx::query(
+            r#"INSERT INTO room_info (room_id, room_name) VALUES (?, ?)
+               ON CONFLICT(room_id) DO UPDATE SET room_name = ?"#,
+        )
+        .bind(&info.room_id)
+        .bind(&info.room_name)
+        .bind(&info.room_name)
+        .execute(&self.conn)
+        .await?;
 
         Ok(())
     }
@@ -70,7 +67,7 @@ impl Rooms for Database {
     async fn get_room_info(&self, room_id: &str) -> Result<Option<RoomInfo>, DataError> {
         let info = sqlx::query!(
             r#"SELECT room_id, room_name FROM room_info
-                        WHERE room_id = ?"#,
+               WHERE room_id = ?"#,
             room_id
         )
         .fetch_optional(&self.conn)
@@ -85,7 +82,7 @@ impl Rooms for Database {
     async fn get_rooms_for_user(&self, user_id: &str) -> Result<HashSet<String>, DataError> {
         let room_ids = sqlx::query!(
             r#"SELECT room_id FROM room_users
-                        WHERE username = ?"#,
+               WHERE username = ?"#,
             user_id
         )
         .fetch_all(&self.conn)
@@ -107,16 +104,14 @@ impl Rooms for Database {
     }
 
     async fn add_user_to_room(&self, username: &str, room_id: &str) -> Result<(), DataError> {
-        // This is here because it is possible to process a bunch of
-        // user join/leave events at once, and we don't want to cause
-        // constraint violation errors.
-        self.remove_user_from_room(username, room_id).await.ok();
-
-        sqlx::query("INSERT INTO room_users (room_id, username) VALUES (?, ?)")
-            .bind(room_id)
-            .bind(username)
-            .execute(&self.conn)
-            .await?;
+        sqlx::query(
+            "INSERT INTO room_users (room_id, username) VALUES (?, ?)
+             ON CONFLICT DO NOTHING",
+        )
+        .bind(room_id)
+        .bind(username)
+        .execute(&self.conn)
+        .await?;
 
         Ok(())
     }
@@ -134,16 +129,19 @@ impl Rooms for Database {
     async fn clear_info(&self, room_id: &str) -> Result<(), DataError> {
         // We do not clear event history here, because if we rejoin a
         // room, we would re-process events we've already seen.
+        let mut tx = self.conn.begin().await?;
+
         sqlx::query("DELETE FROM room_info where room_id = ?")
             .bind(room_id)
-            .execute(&self.conn)
+            .execute(&mut tx)
             .await?;
 
         sqlx::query("DELETE FROM room_users where room_id = ?")
             .bind(room_id)
-            .execute(&self.conn)
+            .execute(&mut tx)
             .await?;
 
+        tx.commit().await?;
         Ok(())
     }
 }