Move the logic from the storage to the query API

src/github.com/matrix-org/dendrite/roomserver/query/query.go

@@ -40,6 +40,9 @@ type RoomserverQueryAPIDatabase interface {
 	// Lookup the numeric IDs for a list of events.
 	// Returns an error if there was a problem talking to the database.
 	EventNIDs(eventIDs []string) (map[string]types.EventNID, error)
+	// Lookup the event IDs for a batch of event numeric IDs.
+	// Returns an error if the retrieval went wrong.
+	EventIDs(eventNIDs []types.EventNID) (map[types.EventNID]string, error)
 	// Save a given room alias with the room ID it refers to.
 	// Returns an error if there was a problem talking to the database.
 	SetRoomAlias(alias string, roomID string) error
@@ -52,13 +55,16 @@ type RoomserverQueryAPIDatabase interface {
 	// Remove a given room alias.
 	// Returns an error if there was a problem talking to the database.
 	RemoveRoomAlias(alias string) error
-	// Lookup the join events for all members in a room as requested by a given
+	// Lookup the membership of a given user in a given room.
-	// user. If the user is currently in the room, returns the room's current
+	// Returns the numeric ID of the latest membership event sent from this user
-	// members, if not returns an empty array (TODO: Fix it)
+	// in this room, along a boolean set to true if the user is still in this room,
-	// If the user requesting the list of members has never been in the room,
+	// false if not.
-	// returns nil.
+	// Returns an error if there was a problem talking to the database.
-	// If there was an issue retrieving the events, returns an error.
+	GetMembership(roomNID types.RoomNID, requestSenderUserID string) (membershipEventNID types.EventNID, stillInRoom bool, err error)
-	GetMembershipEvents(roomNID types.RoomNID, requestSenderUserID string) (events []types.Event, err error)
+	// Lookup the "join" membership event numeric IDs for all user that are
+	// currently members of a given room.
+	// Returns an error if there was a problem talking to the database.
+	GetJoinMembershipEventNIDsForRoom(roomNID types.RoomNID) ([]types.EventNID, error)
 }
 
 // RoomserverQueryAPI is an implementation of api.RoomserverQueryAPI
@@ -199,12 +205,12 @@ func (r *RoomserverQueryAPI) QueryMembershipsForRoom(
 		return err
 	}
 
-	events, err := r.DB.GetMembershipEvents(roomNID, request.Sender)
+	membershipEventNID, stillInRoom, err := r.DB.GetMembership(roomNID, request.Sender)
 	if err != nil {
 		return nil
 	}
 
-	if events == nil {
+	if membershipEventNID == 0 {
 		response.HasBeenInRoom = false
 		response.JoinEvents = nil
 		return nil
@@ -212,6 +218,24 @@ func (r *RoomserverQueryAPI) QueryMembershipsForRoom(
 
 	response.HasBeenInRoom = true
 	response.JoinEvents = []gomatrixserverlib.ClientEvent{}
+
+	var events []types.Event
+	if stillInRoom {
+		var eventNIDs []types.EventNID
+		eventNIDs, err = r.DB.GetJoinMembershipEventNIDsForRoom(roomNID)
+		if err != nil {
+			return err
+		}
+
+		events, err = r.DB.Events(eventNIDs)
+	} else {
+		events, err = r.getMembershipsBeforeEventNID(membershipEventNID)
+	}
+
+	if err != nil {
+		return err
+	}
+
 	for _, event := range events {
 		clientEvent := gomatrixserverlib.ToClientEvent(event.Event, gomatrixserverlib.FormatAll)
 		response.JoinEvents = append(response.JoinEvents, clientEvent)
@@ -220,6 +244,59 @@ func (r *RoomserverQueryAPI) QueryMembershipsForRoom(
 	return nil
 }
 
+// getMembershipsBeforeEventNID takes the numeric ID of an event and fetches the state
+// of the event's room as it was when this event was fired, then filters the state events to
+// only keep the "m.room.member" events with a "join" membership. These events are returned.
+// Returns an error if there was an issue fetching the events.
+func (r *RoomserverQueryAPI) getMembershipsBeforeEventNID(eventNID types.EventNID) ([]types.Event, error) {
+	events := []types.Event{}
+	// Lookup the event NID
+	eIDs, err := r.DB.EventIDs([]types.EventNID{eventNID})
+	if err != nil {
+		return nil, err
+	}
+	eventIDs := []string{eIDs[eventNID]}
+
+	prevState, err := r.DB.StateAtEventIDs(eventIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	// Fetch the state as it was when this event was fired
+	stateEntries, err := state.LoadCombinedStateAfterEvents(r.DB, prevState)
+	if err != nil {
+		return nil, err
+	}
+
+	var eventNIDs []types.EventNID
+	for _, entry := range stateEntries {
+		// Filter the events to retrieve to only keep the membership events
+		if entry.EventStateKeyNID == types.MRoomMemberNID {
+			eventNIDs = append(eventNIDs, entry.EventNID)
+		}
+	}
+
+	// Get all of the events in this state
+	stateEvents, err := r.DB.Events(eventNIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	// Filter the events to only keep the "join" membership events
+	for _, event := range stateEvents {
+		membership, err := event.Membership()
+		if err != nil {
+			return nil, err
+		}
+
+		if membership == "join" {
+			events = append(events, event)
+		}
+	}
+
+	return events, nil
+}
+
 // SetupHTTP adds the RoomserverQueryAPI handlers to the http.ServeMux.
 func (r *RoomserverQueryAPI) SetupHTTP(servMux *http.ServeMux) {
 	servMux.Handle(

src/github.com/matrix-org/dendrite/roomserver/storage/storage.go

@@ -19,7 +19,6 @@ import (
 
 	// Import the postgres database driver.
 	_ "github.com/lib/pq"
-	"github.com/matrix-org/dendrite/roomserver/state"
 	"github.com/matrix-org/dendrite/roomserver/types"
 	"github.com/matrix-org/gomatrixserverlib"
 )
@@ -509,8 +508,8 @@ func (u *membershipUpdater) SetToLeave(senderUserID string, eventID string) ([]s
 	return inviteEventIDs, nil
 }
 
-// GetMembershipEvents implements query.RoomserverQueryAPIDB
+// GetMembership implements query.RoomserverQueryAPIDB
-func (d *Database) GetMembershipEvents(roomNID types.RoomNID, requestSenderUserID string) (events []types.Event, err error) {
+func (d *Database) GetMembership(roomNID types.RoomNID, requestSenderUserID string) (membershipEventNID types.EventNID, stillInRoom bool, err error) {
 	txn, err := d.db.Begin()
 	if err != nil {
 		return
@@ -525,79 +524,17 @@ func (d *Database) GetMembershipEvents(roomNID types.RoomNID, requestSenderUserI
 	senderMembershipEventNID, senderMembership, err := d.statements.selectMembershipFromRoomAndTarget(roomNID, requestSenderUserNID)
 	if err == sql.ErrNoRows {
 		// The user has never been a member of that room
-		return nil, nil
+		return 0, false, nil
 	} else if err != nil {
 		return
 	}
 
-	if senderMembership == membershipStateJoin {
+	return senderMembershipEventNID, senderMembership == membershipStateJoin, nil
-		// The user is still in the room: Send the current list of joined members
-		var joinEventNIDs []types.EventNID
-		joinEventNIDs, err = d.statements.selectMembershipsFromRoomAndMembership(roomNID, membershipStateJoin)
-		if err != nil {
-			return nil, err
-		}
-
-		events, err = d.Events(joinEventNIDs)
-	} else {
-		// The user isn't in the room anymore: Send the list of joined user from
-		// when the user left
-		events, err = d.getMembershipsBeforeEventNID(senderMembershipEventNID)
-	}
-
-	return
 }
 
-// getMembershipsBeforeEventNID takes the numeric ID of an event and fetches the state
+// GetJoinMembershipEventNIDsForRoom implements query.RoomserverQueryAPIDB
-// of the event's room as it was when this event was fired, then filters the state events to
+func (d *Database) GetJoinMembershipEventNIDsForRoom(roomNID types.RoomNID) ([]types.EventNID, error) {
-// only keep the "m.room.member" events with a "join" membership. These events are returned.
+	return d.statements.selectMembershipsFromRoomAndMembership(roomNID, membershipStateJoin)
-// Returns an error if there was an issue fetching the events.
-func (d *Database) getMembershipsBeforeEventNID(eventNID types.EventNID) ([]types.Event, error) {
-	events := []types.Event{}
-	// Lookup the event NID
-	eIDs, err := d.EventIDs([]types.EventNID{eventNID})
-	if err != nil {
-		return nil, err
-	}
-	eventIDs := []string{eIDs[eventNID]}
-
-	prevState, err := d.StateAtEventIDs(eventIDs)
-	if err != nil {
-		return nil, err
-	}
-
-	// Fetch the state as it was when this event was fired
-	stateEntries, err := state.LoadCombinedStateAfterEvents(d, prevState)
-	if err != nil {
-		return nil, err
-	}
-
-	var eventNIDs []types.EventNID
-	for _, entry := range stateEntries {
-		if entry.EventStateKeyNID == types.MRoomMemberNID {
-			eventNIDs = append(eventNIDs, entry.EventNID)
-		}
-	}
-
-	// Get all of the events in this state
-	stateEvents, err := d.Events(eventNIDs)
-	if err != nil {
-		return nil, err
-	}
-
-	// Filter the events to only keep the "join" membership events
-	for _, event := range stateEvents {
-		membership, err := event.Membership()
-		if err != nil {
-			return nil, err
-		}
-
-		if membership == "join" {
-			events = append(events, event)
-		}
-	}
-
-	return events, nil
 }
 
 type transaction struct {