Move currentstateserver API to roomserver (#1387)

* Move currentstateserver API to roomserver

Stub out DB functions for now, nothing uses the roomserver version yet.

* Allow it to startup

* Implement some current-state-server storage interface functions

* Add missing package

roomserver/api/wrapper.go

@@ -133,3 +133,102 @@ func GetEvent(ctx context.Context, rsAPI RoomserverInternalAPI, eventID string)
 	}
 	return &res.Events[0]
 }
+
+// GetStateEvent returns the current state event in the room or nil.
+func GetStateEvent(ctx context.Context, rsAPI RoomserverInternalAPI, roomID string, tuple gomatrixserverlib.StateKeyTuple) *gomatrixserverlib.HeaderedEvent {
+	var res QueryCurrentStateResponse
+	err := rsAPI.QueryCurrentState(ctx, &QueryCurrentStateRequest{
+		RoomID:      roomID,
+		StateTuples: []gomatrixserverlib.StateKeyTuple{tuple},
+	}, &res)
+	if err != nil {
+		util.GetLogger(ctx).WithError(err).Error("Failed to QueryCurrentState")
+		return nil
+	}
+	ev, ok := res.StateEvents[tuple]
+	if ok {
+		return ev
+	}
+	return nil
+}
+
+// IsServerBannedFromRoom returns whether the server is banned from a room by server ACLs.
+func IsServerBannedFromRoom(ctx context.Context, rsAPI RoomserverInternalAPI, roomID string, serverName gomatrixserverlib.ServerName) bool {
+	req := &QueryServerBannedFromRoomRequest{
+		ServerName: serverName,
+		RoomID:     roomID,
+	}
+	res := &QueryServerBannedFromRoomResponse{}
+	if err := rsAPI.QueryServerBannedFromRoom(ctx, req, res); err != nil {
+		util.GetLogger(ctx).WithError(err).Error("Failed to QueryServerBannedFromRoom")
+		return true
+	}
+	return res.Banned
+}
+
+// PopulatePublicRooms extracts PublicRoom information for all the provided room IDs. The IDs are not checked to see if they are visible in the
+// published room directory.
+// due to lots of switches
+// nolint:gocyclo
+func PopulatePublicRooms(ctx context.Context, roomIDs []string, rsAPI RoomserverInternalAPI) ([]gomatrixserverlib.PublicRoom, error) {
+	avatarTuple := gomatrixserverlib.StateKeyTuple{EventType: "m.room.avatar", StateKey: ""}
+	nameTuple := gomatrixserverlib.StateKeyTuple{EventType: "m.room.name", StateKey: ""}
+	canonicalTuple := gomatrixserverlib.StateKeyTuple{EventType: gomatrixserverlib.MRoomCanonicalAlias, StateKey: ""}
+	topicTuple := gomatrixserverlib.StateKeyTuple{EventType: "m.room.topic", StateKey: ""}
+	guestTuple := gomatrixserverlib.StateKeyTuple{EventType: "m.room.guest_access", StateKey: ""}
+	visibilityTuple := gomatrixserverlib.StateKeyTuple{EventType: gomatrixserverlib.MRoomHistoryVisibility, StateKey: ""}
+	joinRuleTuple := gomatrixserverlib.StateKeyTuple{EventType: gomatrixserverlib.MRoomJoinRules, StateKey: ""}
+
+	var stateRes QueryBulkStateContentResponse
+	err := rsAPI.QueryBulkStateContent(ctx, &QueryBulkStateContentRequest{
+		RoomIDs:        roomIDs,
+		AllowWildcards: true,
+		StateTuples: []gomatrixserverlib.StateKeyTuple{
+			nameTuple, canonicalTuple, topicTuple, guestTuple, visibilityTuple, joinRuleTuple, avatarTuple,
+			{EventType: gomatrixserverlib.MRoomMember, StateKey: "*"},
+		},
+	}, &stateRes)
+	if err != nil {
+		util.GetLogger(ctx).WithError(err).Error("QueryBulkStateContent failed")
+		return nil, err
+	}
+	chunk := make([]gomatrixserverlib.PublicRoom, len(roomIDs))
+	i := 0
+	for roomID, data := range stateRes.Rooms {
+		pub := gomatrixserverlib.PublicRoom{
+			RoomID: roomID,
+		}
+		joinCount := 0
+		var joinRule, guestAccess string
+		for tuple, contentVal := range data {
+			if tuple.EventType == gomatrixserverlib.MRoomMember && contentVal == "join" {
+				joinCount++
+				continue
+			}
+			switch tuple {
+			case avatarTuple:
+				pub.AvatarURL = contentVal
+			case nameTuple:
+				pub.Name = contentVal
+			case topicTuple:
+				pub.Topic = contentVal
+			case canonicalTuple:
+				pub.CanonicalAlias = contentVal
+			case visibilityTuple:
+				pub.WorldReadable = contentVal == "world_readable"
+			// need both of these to determine whether guests can join
+			case joinRuleTuple:
+				joinRule = contentVal
+			case guestTuple:
+				guestAccess = contentVal
+			}
+		}
+		if joinRule == gomatrixserverlib.Public && guestAccess == "can_join" {
+			pub.GuestCanJoin = true
+		}
+		pub.JoinedMembersCount = joinCount
+		chunk[i] = pub
+		i++
+	}
+	return chunk, nil
+}