Implement history visibility on /messages, /context, /sync (#2511)

* Add possibility to set history_visibility and user AccountType

* Add new DB queries

* Add actual history_visibility changes for /messages

* Add passing tests

* Extract check function

* Cleanup

* Cleanup

* Fix build on 386

* Move ApplyHistoryVisibilityFilter to internal

* Move queries to topology table

* Add filtering to /sync and /context
Some cleanup

* Add passing tests; Remove failing tests :(

* Re-add passing tests

* Move filtering to own function to avoid duplication

* Re-add passing test

* Use newly added GMSL HistoryVisibility

* Update gomatrixserverlib

* Set the visibility when creating events

* Default to shared history visibility

* Remove unused query

* Update history visibility checks to use gmsl
Update tests

* Remove unused statement

* Update migrations to set "correct" history visibility

* Add method to fetch the membership at a given event

* Tweaks and logging

* Use actual internal rsAPI, default to shared visibility in tests

* Revert "Move queries to topology table"

This reverts commit 4f0d41be9c194a46379796435ce73e79203edbd6.

* Remove noise/unneeded code

* More cleanup

* Try to optimize database requests

* Fix imports

* PR peview fixes/changes

* Move setting history visibility to own migration, be more restrictive

* Fix unit tests

* Lint

* Fix missing entries

* Tweaks for incremental syncs

* Adapt generic changes

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>
Co-authored-by: kegsay <kegan@matrix.org>

roomserver/internal/helpers/helpers.go

@@ -208,6 +208,12 @@ func StateBeforeEvent(ctx context.Context, db storage.Database, info *types.Room
 	return roomState.LoadCombinedStateAfterEvents(ctx, prevState)
 }
 
+func MembershipAtEvent(ctx context.Context, db storage.Database, info *types.RoomInfo, eventIDs []string, stateKeyNID types.EventStateKeyNID) (map[string][]types.StateEntry, error) {
+	roomState := state.NewStateResolution(db, info)
+	// Fetch the state as it was when this event was fired
+	return roomState.LoadMembershipAtEvent(ctx, eventIDs, stateKeyNID)
+}
+
 func LoadEvents(
 	ctx context.Context, db storage.Database, eventNIDs []types.EventNID,
 ) ([]*gomatrixserverlib.Event, error) {

roomserver/internal/input/input_events.go

@@ -299,7 +299,7 @@ func (r *Inputer) processRoomEvent(
 	// allowed at the time, and also to get the history visibility. We won't
 	// bother doing this if the event was already rejected as it just ends up
 	// burning CPU time.
-	historyVisibility := gomatrixserverlib.HistoryVisibilityJoined // Default to restrictive.
+	historyVisibility := gomatrixserverlib.HistoryVisibilityShared // Default to shared.
 	if rejectionErr == nil && !isRejected && !softfail {
 		var err error
 		historyVisibility, rejectionErr, err = r.processStateBefore(ctx, input, missingPrev)
@@ -429,7 +429,7 @@ func (r *Inputer) processStateBefore(
 	input *api.InputRoomEvent,
 	missingPrev bool,
 ) (historyVisibility gomatrixserverlib.HistoryVisibility, rejectionErr error, err error) {
-	historyVisibility = gomatrixserverlib.HistoryVisibilityJoined // Default to restrictive.
+	historyVisibility = gomatrixserverlib.HistoryVisibilityShared // Default to shared.
 	event := input.Event.Unwrap()
 	isCreateEvent := event.Type() == gomatrixserverlib.MRoomCreate && event.StateKeyEquals("")
 	var stateBeforeEvent []*gomatrixserverlib.Event

roomserver/internal/query/query.go

@@ -204,6 +204,54 @@ func (r *Queryer) QueryMembershipForUser(
 	return err
 }
 
+func (r *Queryer) QueryMembershipAtEvent(
+	ctx context.Context,
+	request *api.QueryMembershipAtEventRequest,
+	response *api.QueryMembershipAtEventResponse,
+) error {
+	response.Memberships = make(map[string][]*gomatrixserverlib.HeaderedEvent)
+	info, err := r.DB.RoomInfo(ctx, request.RoomID)
+	if err != nil {
+		return fmt.Errorf("unable to get roomInfo: %w", err)
+	}
+	if info == nil {
+		return fmt.Errorf("no roomInfo found")
+	}
+
+	// get the users stateKeyNID
+	stateKeyNIDs, err := r.DB.EventStateKeyNIDs(ctx, []string{request.UserID})
+	if err != nil {
+		return fmt.Errorf("unable to get stateKeyNIDs for %s: %w", request.UserID, err)
+	}
+	if _, ok := stateKeyNIDs[request.UserID]; !ok {
+		return fmt.Errorf("requested stateKeyNID for %s was not found", request.UserID)
+	}
+
+	stateEntries, err := helpers.MembershipAtEvent(ctx, r.DB, info, request.EventIDs, stateKeyNIDs[request.UserID])
+	if err != nil {
+		return fmt.Errorf("unable to get state before event: %w", err)
+	}
+
+	for _, eventID := range request.EventIDs {
+		stateEntry := stateEntries[eventID]
+		memberships, err := helpers.GetMembershipsAtState(ctx, r.DB, stateEntry, false)
+		if err != nil {
+			return fmt.Errorf("unable to get memberships at state: %w", err)
+		}
+		res := make([]*gomatrixserverlib.HeaderedEvent, 0, len(memberships))
+
+		for i := range memberships {
+			ev := memberships[i]
+			if ev.Type() == gomatrixserverlib.MRoomMember && ev.StateKeyEquals(request.UserID) {
+				res = append(res, ev.Headered(info.RoomVersion))
+			}
+		}
+		response.Memberships[eventID] = res
+	}
+
+	return nil
+}
+
 // QueryMembershipsForRoom implements api.RoomserverInternalAPI
 func (r *Queryer) QueryMembershipsForRoom(
 	ctx context.Context,