Room version abstractions (#865)

* Rough first pass at adding room version abstractions

* Define newer room versions

* Update room version metadata

* Fix roomserver/versions

* Try to fix whitespace in roomsSchema

roomserver/storage/postgres/rooms_table.go

@@ -39,7 +39,10 @@ CREATE TABLE IF NOT EXISTS roomserver_rooms (
     last_event_sent_nid BIGINT NOT NULL DEFAULT 0,
     -- The state of the room after the current set of latest events.
     -- This will be 0 if there are no latest events in the room.
-    state_snapshot_nid BIGINT NOT NULL DEFAULT 0
+    state_snapshot_nid BIGINT NOT NULL DEFAULT 0,
+    -- The version of the room, which will assist in determining the state resolution
+    -- algorithm, event ID format, etc.
+    room_version BIGINT NOT NULL DEFAULT 1
 );
 `
 
@@ -61,12 +64,16 @@ const selectLatestEventNIDsForUpdateSQL = "" +
 const updateLatestEventNIDsSQL = "" +
 	"UPDATE roomserver_rooms SET latest_event_nids = $2, last_event_sent_nid = $3, state_snapshot_nid = $4 WHERE room_nid = $1"
 
+const selectRoomVersionForRoomNIDSQL = "" +
+	"SELECT room_version FROM roomserver_rooms WHERE room_nid = $1"
+
 type roomStatements struct {
 	insertRoomNIDStmt                  *sql.Stmt
 	selectRoomNIDStmt                  *sql.Stmt
 	selectLatestEventNIDsStmt          *sql.Stmt
 	selectLatestEventNIDsForUpdateStmt *sql.Stmt
 	updateLatestEventNIDsStmt          *sql.Stmt
+	selectRoomVersionForRoomNIDStmt    *sql.Stmt
 }
 
 func (s *roomStatements) prepare(db *sql.DB) (err error) {
@@ -80,6 +87,7 @@ func (s *roomStatements) prepare(db *sql.DB) (err error) {
 		{&s.selectLatestEventNIDsStmt, selectLatestEventNIDsSQL},
 		{&s.selectLatestEventNIDsForUpdateStmt, selectLatestEventNIDsForUpdateSQL},
 		{&s.updateLatestEventNIDsStmt, updateLatestEventNIDsSQL},
+		{&s.selectRoomVersionForRoomNIDStmt, selectRoomVersionForRoomNIDSQL},
 	}.prepare(db)
 }
 
@@ -154,3 +162,12 @@ func (s *roomStatements) updateLatestEventNIDs(
 	)
 	return err
 }
+
+func (s *roomStatements) selectRoomVersionForRoomNID(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) (int64, error) {
+	var roomVersion int64
+	stmt := common.TxStmt(txn, s.selectRoomVersionForRoomNIDStmt)
+	err := stmt.QueryRowContext(ctx, roomNID).Scan(&roomVersion)
+	return roomVersion, err
+}

roomserver/storage/postgres/storage.go

@@ -697,6 +697,14 @@ func (d *Database) EventsFromIDs(ctx context.Context, eventIDs []string) ([]type
 	return d.Events(ctx, nids)
 }
 
+func (d *Database) GetRoomVersionForRoom(
+	ctx context.Context, roomNID types.RoomNID,
+) (int64, error) {
+	return d.statements.selectRoomVersionForRoomNID(
+		ctx, nil, roomNID,
+	)
+}
+
 type transaction struct {
 	ctx context.Context
 	txn *sql.Tx

roomserver/storage/storage.go

@@ -54,6 +54,8 @@ type Database interface {
 	GetMembership(ctx context.Context, roomNID types.RoomNID, requestSenderUserID string) (membershipEventNID types.EventNID, stillInRoom bool, err error)
 	GetMembershipEventNIDsForRoom(ctx context.Context, roomNID types.RoomNID, joinOnly bool) ([]types.EventNID, error)
 	EventsFromIDs(ctx context.Context, eventIDs []string) ([]types.Event, error)
+	GetRoomVersionForRoom(ctx context.Context, roomNID types.RoomNID) (int64, error)
+	//GetRoomVersionForEvent(ctx context.Context, eventNID types.EventNID) int64
 }
 
 // NewPublicRoomsServerDatabase opens a database connection.