Add RoomInfo metadata struct (#1367)

* Add RoomInfo struct

* Remove RoomNID and replace with RoomInfo

* Bugfix and remove another needless query

* nil guard

5 files changed, 50 insertions, 36 deletions

diff --git a/roomserver/storage/interface.go b/roomserver/storage/interface.go
index 545885f7..5f641614 100644
--- a/roomserver/storage/interface.go
+++ b/roomserver/storage/interface.go
@@ -26,6 +26,8 @@ import (
 type Database interface {
 	// Do we support processing input events for more than one room at a time?
 	SupportsConcurrentRoomInputs() bool
+	// RoomInfo returns room information for the given room ID, or nil if there is no room.
+	RoomInfo(ctx context.Context, roomID string) (*types.RoomInfo, error)
 	// Store the room state at an event in the database
 	AddState(
 		ctx context.Context,
@@ -94,14 +96,6 @@ type Database interface {
 	// This is used to determine if the room event is processed/processing already.
 	// Returns an empty string if no such event exists.
 	GetTransactionEventID(ctx context.Context, transactionID string, sessionID int64, userID string) (string, error)
-	// Look up the numeric ID for the room.
-	// Returns 0 if the room doesn't exists.
-	// Returns an error if there was a problem talking to the database.
-	RoomNID(ctx context.Context, roomID string) (types.RoomNID, error)
-	// RoomNIDExcludingStubs is a special variation of RoomNID that will return 0 as if the room
-	// does not exist if the room has no latest events. This can happen when we've received an
-	// invite over federation for a room that we don't know anything else about yet.
-	RoomNIDExcludingStubs(ctx context.Context, roomID string) (types.RoomNID, error)
 	// Look up event references for the latest events in the room and the current state snapshot.
 	// Returns the latest events, the current state and the maximum depth of the latest events plus 1.
 	// Returns an error if there was a problem talking to the database.
diff --git a/roomserver/storage/postgres/rooms_table.go b/roomserver/storage/postgres/rooms_table.go
index 8e00cfdb..691c04ba 100644
--- a/roomserver/storage/postgres/rooms_table.go
+++ b/roomserver/storage/postgres/rooms_table.go
@@ -74,6 +74,9 @@ const selectRoomVersionForRoomIDSQL = "" +
 const selectRoomVersionForRoomNIDSQL = "" +
 	"SELECT room_version FROM roomserver_rooms WHERE room_nid = $1"
 
+const selectRoomInfoSQL = "" +
+	"SELECT room_version, room_nid, state_snapshot_nid, latest_event_nids FROM roomserver_rooms WHERE room_id = $1"
+
 type roomStatements struct {
 	insertRoomNIDStmt                  *sql.Stmt
 	selectRoomNIDStmt                  *sql.Stmt
@@ -82,6 +85,7 @@ type roomStatements struct {
 	updateLatestEventNIDsStmt          *sql.Stmt
 	selectRoomVersionForRoomIDStmt     *sql.Stmt
 	selectRoomVersionForRoomNIDStmt    *sql.Stmt
+	selectRoomInfoStmt                 *sql.Stmt
 }
 
 func NewPostgresRoomsTable(db *sql.DB) (tables.Rooms, error) {
@@ -98,6 +102,7 @@ func NewPostgresRoomsTable(db *sql.DB) (tables.Rooms, error) {
 		{&s.updateLatestEventNIDsStmt, updateLatestEventNIDsSQL},
 		{&s.selectRoomVersionForRoomIDStmt, selectRoomVersionForRoomIDSQL},
 		{&s.selectRoomVersionForRoomNIDStmt, selectRoomVersionForRoomNIDSQL},
+		{&s.selectRoomInfoStmt, selectRoomInfoSQL},
 	}.Prepare(db)
 }
 
@@ -111,6 +116,19 @@ func (s *roomStatements) InsertRoomNID(
 	return types.RoomNID(roomNID), err
 }
 
+func (s *roomStatements) SelectRoomInfo(ctx context.Context, roomID string) (*types.RoomInfo, error) {
+	var info types.RoomInfo
+	var latestNIDs pq.Int64Array
+	err := s.selectRoomInfoStmt.QueryRowContext(ctx, roomID).Scan(
+		&info.RoomVersion, &info.RoomNID, &info.StateSnapshotNID, &latestNIDs,
+	)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	info.IsStub = len(latestNIDs) == 0
+	return &info, err
+}
+
 func (s *roomStatements) SelectRoomNID(
 	ctx context.Context, txn *sql.Tx, roomID string,
 ) (types.RoomNID, error) {
diff --git a/roomserver/storage/shared/storage.go b/roomserver/storage/shared/storage.go
index 50ab5dde..4af61be8 100644
--- a/roomserver/storage/shared/storage.go
+++ b/roomserver/storage/shared/storage.go
@@ -120,6 +120,10 @@ func (d *Database) StateEntriesForTuples(
 	)
 }
 
+func (d *Database) RoomInfo(ctx context.Context, roomID string) (*types.RoomInfo, error) {
+	return d.RoomsTable.SelectRoomInfo(ctx, roomID)
+}
+
 func (d *Database) AddState(
 	ctx context.Context,
 	roomNID types.RoomNID,
@@ -194,34 +198,6 @@ func (d *Database) EventsFromIDs(ctx context.Context, eventIDs []string) ([]type
 	return d.Events(ctx, nids)
 }
 
-func (d *Database) RoomNID(ctx context.Context, roomID string) (types.RoomNID, error) {
-	if nid, ok := d.Cache.GetRoomServerRoomNID(roomID); ok {
-		return nid, nil
-	}
-	roomNID, err := d.RoomsTable.SelectRoomNID(ctx, nil, roomID)
-	if err == sql.ErrNoRows {
-		return 0, nil
-	}
-	d.Cache.StoreRoomServerRoomNID(roomID, roomNID)
-	return roomNID, err
-}
-
-func (d *Database) RoomNIDExcludingStubs(ctx context.Context, roomID string) (roomNID types.RoomNID, err error) {
-	roomNID, err = d.RoomNID(ctx, roomID)
-	if err != nil {
-		return
-	}
-	latestEvents, _, err := d.RoomsTable.SelectLatestEventNIDs(ctx, nil, roomNID)
-	if err != nil {
-		return
-	}
-	if len(latestEvents) == 0 {
-		roomNID = 0
-		return
-	}
-	return
-}
-
 func (d *Database) LatestEventIDs(
 	ctx context.Context, roomNID types.RoomNID,
 ) (references []gomatrixserverlib.EventReference, currentStateSnapshotNID types.StateSnapshotNID, depth int64, err error) {
diff --git a/roomserver/storage/sqlite3/rooms_table.go b/roomserver/storage/sqlite3/rooms_table.go
index 6541cc0c..fc1bcf22 100644
--- a/roomserver/storage/sqlite3/rooms_table.go
+++ b/roomserver/storage/sqlite3/rooms_table.go
@@ -64,6 +64,9 @@ const selectRoomVersionForRoomIDSQL = "" +
 const selectRoomVersionForRoomNIDSQL = "" +
 	"SELECT room_version FROM roomserver_rooms WHERE room_nid = $1"
 
+const selectRoomInfoSQL = "" +
+	"SELECT room_version, room_nid, state_snapshot_nid, latest_event_nids FROM roomserver_rooms WHERE room_id = $1"
+
 type roomStatements struct {
 	db                                 *sql.DB
 	insertRoomNIDStmt                  *sql.Stmt
@@ -73,6 +76,7 @@ type roomStatements struct {
 	updateLatestEventNIDsStmt          *sql.Stmt
 	selectRoomVersionForRoomIDStmt     *sql.Stmt
 	selectRoomVersionForRoomNIDStmt    *sql.Stmt
+	selectRoomInfoStmt                 *sql.Stmt
 }
 
 func NewSqliteRoomsTable(db *sql.DB) (tables.Rooms, error) {
@@ -91,9 +95,30 @@ func NewSqliteRoomsTable(db *sql.DB) (tables.Rooms, error) {
 		{&s.updateLatestEventNIDsStmt, updateLatestEventNIDsSQL},
 		{&s.selectRoomVersionForRoomIDStmt, selectRoomVersionForRoomIDSQL},
 		{&s.selectRoomVersionForRoomNIDStmt, selectRoomVersionForRoomNIDSQL},
+		{&s.selectRoomInfoStmt, selectRoomInfoSQL},
 	}.Prepare(db)
 }
 
+func (s *roomStatements) SelectRoomInfo(ctx context.Context, roomID string) (*types.RoomInfo, error) {
+	var info types.RoomInfo
+	var latestNIDsJSON string
+	err := s.selectRoomInfoStmt.QueryRowContext(ctx, roomID).Scan(
+		&info.RoomVersion, &info.RoomNID, &info.StateSnapshotNID, &latestNIDsJSON,
+	)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, nil
+		}
+		return nil, err
+	}
+	var latestNIDs []int64
+	if err = json.Unmarshal([]byte(latestNIDsJSON), &latestNIDs); err != nil {
+		return nil, err
+	}
+	info.IsStub = len(latestNIDs) == 0
+	return &info, err
+}
+
 func (s *roomStatements) InsertRoomNID(
 	ctx context.Context, txn *sql.Tx,
 	roomID string, roomVersion gomatrixserverlib.RoomVersion,
diff --git a/roomserver/storage/tables/interface.go b/roomserver/storage/tables/interface.go
index 47c12c2c..ca9159d0 100644
--- a/roomserver/storage/tables/interface.go
+++ b/roomserver/storage/tables/interface.go
@@ -65,6 +65,7 @@ type Rooms interface {
 	UpdateLatestEventNIDs(ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, eventNIDs []types.EventNID, lastEventSentNID types.EventNID, stateSnapshotNID types.StateSnapshotNID) error
 	SelectRoomVersionForRoomID(ctx context.Context, txn *sql.Tx, roomID string) (gomatrixserverlib.RoomVersion, error)
 	SelectRoomVersionForRoomNID(ctx context.Context, roomNID types.RoomNID) (gomatrixserverlib.RoomVersion, error)
+	SelectRoomInfo(ctx context.Context, roomID string) (*types.RoomInfo, error)
 }
 
 type Transactions interface {