From a571989495ac0b8d4598561a1ff750bffac665cf Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Fri, 11 Sep 2020 14:17:33 +0100
Subject: [PATCH] Rename to PurgeRoom

---
 syncapi/consumers/roomserver.go      | 11 ++------
 syncapi/storage/interface.go         |  6 ++---
 syncapi/storage/shared/syncserver.go | 40 +++++++++-------------------
 3 files changed, 18 insertions(+), 39 deletions(-)

diff --git a/syncapi/consumers/roomserver.go b/syncapi/consumers/roomserver.go
index ca697e425..68ed61c08 100644
--- a/syncapi/consumers/roomserver.go
+++ b/syncapi/consumers/roomserver.go
@@ -145,15 +145,8 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 	}
 
 	if msg.RewritesState {
-		err = s.db.RewriteState(
-			ctx,
-			&ev,
-			addsStateEvents,
-			msg.AddsStateEventIDs,
-			msg.TransactionID,
-		)
-		if err != nil {
-			return fmt.Errorf("s.db.RewriteState: %w", err)
+		if err = s.db.PurgeRoom(ctx, ev.RoomID()); err != nil {
+			return fmt.Errorf("s.db.PurgeRoom: %w", err)
 		}
 	}
 
diff --git a/syncapi/storage/interface.go b/syncapi/storage/interface.go
index 04f2eb346..f6e8c4933 100644
--- a/syncapi/storage/interface.go
+++ b/syncapi/storage/interface.go
@@ -41,9 +41,9 @@ type Database interface {
 	// Returns an error if there was a problem inserting this event.
 	WriteEvent(ctx context.Context, ev *gomatrixserverlib.HeaderedEvent, addStateEvents []gomatrixserverlib.HeaderedEvent,
 		addStateEventIDs []string, removeStateEventIDs []string, transactionID *api.TransactionID, excludeFromSync bool) (types.StreamPosition, error)
-	// RewriteState rewrites a current room state event. If the state event is a create event then all existing
-	// state in the room will be deleted before rewriting the event.
-	RewriteState(ctx context.Context, ev *gomatrixserverlib.HeaderedEvent, addStateEvents []gomatrixserverlib.HeaderedEvent, addStateEventIDs []string, transactionID *api.TransactionID) error
+	// PurgeRoom completely purges room state from the sync API. This is done when
+	// receiving an output event that completely resets the state.
+	PurgeRoom(ctx context.Context, roomID string) error
 	// GetStateEvent returns the Matrix state event of a given type for a given room with a given state key
 	// If no event could be found, returns nil
 	// If there was an issue during the retrieval, returns an error
diff --git a/syncapi/storage/shared/syncserver.go b/syncapi/storage/shared/syncserver.go
index d171eba4f..9e6aad8d8 100644
--- a/syncapi/storage/shared/syncserver.go
+++ b/syncapi/storage/shared/syncserver.go
@@ -241,39 +241,25 @@ func (d *Database) handleBackwardExtremities(ctx context.Context, txn *sql.Tx, e
 	return nil
 }
 
-func (d *Database) RewriteState(
-	ctx context.Context,
-	ev *gomatrixserverlib.HeaderedEvent,
-	addStateEvents []gomatrixserverlib.HeaderedEvent,
-	addStateEventIDs []string,
-	transactionID *api.TransactionID,
+func (d *Database) PurgeRoom(
+	ctx context.Context, roomID string,
 ) error {
 	return d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
 		// If the event is a create event then we'll delete all of the existing
 		// data for the room. The only reason that a create event would be replayed
 		// to us in this way is if we're about to receive the entire room state.
-		if ev.Type() == gomatrixserverlib.MRoomCreate {
-			if err := d.CurrentRoomState.DeleteRoomStateForRoom(ctx, txn, ev.RoomID()); err != nil {
-				return fmt.Errorf("d.CurrentRoomState.DeleteRoomStateForRoom: %w", err)
-			}
-			if err := d.OutputEvents.DeleteEventsForRoom(ctx, txn, ev.RoomID()); err != nil {
-				return fmt.Errorf("d.Events.DeleteEventsForRoom: %w", err)
-			}
-			if err := d.Topology.DeleteTopologyForRoom(ctx, txn, ev.RoomID()); err != nil {
-				return fmt.Errorf("d.Topology.DeleteTopologyForRoom: %w", err)
-			}
-			if err := d.BackwardExtremities.DeleteBackwardExtremitiesForRoom(ctx, txn, ev.RoomID()); err != nil {
-				return fmt.Errorf("d.BackwardExtremities.DeleteBackwardExtremitiesForRoom: %w", err)
-			}
+		if err := d.CurrentRoomState.DeleteRoomStateForRoom(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("d.CurrentRoomState.DeleteRoomStateForRoom: %w", err)
+		}
+		if err := d.OutputEvents.DeleteEventsForRoom(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("d.Events.DeleteEventsForRoom: %w", err)
+		}
+		if err := d.Topology.DeleteTopologyForRoom(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("d.Topology.DeleteTopologyForRoom: %w", err)
+		}
+		if err := d.BackwardExtremities.DeleteBackwardExtremitiesForRoom(ctx, txn, roomID); err != nil {
+			return fmt.Errorf("d.BackwardExtremities.DeleteBackwardExtremitiesForRoom: %w", err)
 		}
-
-		/*
-			if err := d.handleBackwardExtremities(ctx, txn, ev); err != nil {
-				return fmt.Errorf("d.handleBackwardExtremities: %w", err)
-			}
-		*/
-		// TODO: is there something better here that we can do instead of giving stream position 0?
-		//return d.updateRoomState(ctx, txn, []string{}, addStateEvents, types.StreamPosition(0))
 		return nil
 	})
 }