3 files changed, 44 insertions, 0 deletions
diff --git a/roomserver/storage/interface.go b/roomserver/storage/interface.go
index ef446378..7787d9f8 100644
--- a/roomserver/storage/interface.go
+++ b/roomserver/storage/interface.go
@@ -31,6 +31,7 @@ type Database interface {
 	UserRoomKeys
 	// Do we support processing input events for more than one room at a time?
 	SupportsConcurrentRoomInputs() bool
+	AssignRoomNID(ctx context.Context, roomID spec.RoomID, roomVersion gomatrixserverlib.RoomVersion) (roomNID types.RoomNID, err error)
 	// 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)
 	RoomInfoByNID(ctx context.Context, roomNID types.RoomNID) (*types.RoomInfo, error)
@@ -212,6 +213,7 @@ type UserRoomKeys interface {
 type RoomDatabase interface {
 	EventDatabase
 	UserRoomKeys
+	AssignRoomNID(ctx context.Context, roomID spec.RoomID, roomVersion gomatrixserverlib.RoomVersion) (roomNID types.RoomNID, err error)
 	// 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)
 	RoomInfoByNID(ctx context.Context, roomNID types.RoomNID) (*types.RoomInfo, error)
diff --git a/roomserver/storage/shared/storage.go b/roomserver/storage/shared/storage.go
index d7ca3cef..bda51da8 100644
--- a/roomserver/storage/shared/storage.go
+++ b/roomserver/storage/shared/storage.go
@@ -662,6 +662,26 @@ func (d *Database) IsEventRejected(ctx context.Context, roomNID types.RoomNID, e
 	return d.EventsTable.SelectEventRejected(ctx, nil, roomNID, eventID)
 }
 
+func (d *Database) AssignRoomNID(ctx context.Context, roomID spec.RoomID, roomVersion gomatrixserverlib.RoomVersion) (roomNID types.RoomNID, err error) {
+	// This should already be checked, let's check it anyway.
+	_, err = gomatrixserverlib.GetRoomVersion(roomVersion)
+	if err != nil {
+		return 0, err
+	}
+	err = d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
+		roomNID, err = d.assignRoomNID(ctx, txn, roomID.String(), roomVersion)
+		if err != nil {
+			return err
+		}
+		return nil
+	})
+	if err != nil {
+		return 0, err
+	}
+	// Not setting caches, as assignRoomNID already does this
+	return roomNID, err
+}
+
 // GetOrCreateRoomInfo gets or creates a new RoomInfo, which is only safe to use with functions only needing a roomVersion or roomNID.
 func (d *Database) GetOrCreateRoomInfo(ctx context.Context, event gomatrixserverlib.PDU) (roomInfo *types.RoomInfo, err error) {
 	// Get the default room version. If the client doesn't supply a room_version
diff --git a/roomserver/storage/shared/storage_test.go b/roomserver/storage/shared/storage_test.go
index 4fa451bc..581d83ee 100644
--- a/roomserver/storage/shared/storage_test.go
+++ b/roomserver/storage/shared/storage_test.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/matrix-org/dendrite/internal/caching"
+	"github.com/matrix-org/dendrite/roomserver/types"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/gomatrixserverlib/spec"
 	"github.com/stretchr/testify/assert"
@@ -199,3 +200,24 @@ func TestUserRoomKeys(t *testing.T) {
 		assert.Error(t, err)
 	})
 }
+
+func TestAssignRoomNID(t *testing.T) {
+	ctx := context.Background()
+	alice := test.NewUser(t)
+	room := test.NewRoom(t, alice)
+
+	roomID, err := spec.NewRoomID(room.ID)
+	assert.NoError(t, err)
+
+	test.WithAllDatabases(t, func(t *testing.T, dbType test.DBType) {
+		db, close := mustCreateRoomserverDatabase(t, dbType)
+		defer close()
+
+		nid, err := db.AssignRoomNID(ctx, *roomID, room.Version)
+		assert.NoError(t, err)
+		assert.Greater(t, nid, types.EventNID(0))
+
+		_, err = db.AssignRoomNID(ctx, spec.RoomID{}, "notaroomversion")
+		assert.Error(t, err)
+	})
+}