Membership events retrieval + update on leave

src/github.com/matrix-org/dendrite/roomserver/input/membership.go

@@ -197,7 +197,7 @@ func updateToLeaveMembership(
 	// are active for that user. We notify the consumers that the invites have
 	// been retired using a special event, even though they could infer this
 	// by studying the state changes in the room event stream.
-	retired, err := mu.SetToLeave(add.Sender())
+	retired, err := mu.SetToLeave(add.Sender(), add.EventID())
 	if err != nil {
 		return nil, err
 	}

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

@@ -58,10 +58,22 @@ const bulkSelectEventStateKeyNIDSQL = "" +
 	"SELECT event_state_key, event_state_key_nid FROM roomserver_event_state_keys" +
 	" WHERE event_state_key = ANY($1)"
 
+const selectEventStateKeySQL = "" +
+	"SELECT event_state_key FROM roomserver_event_state_keys" +
+	" WHERE event_state_key_nid = $1"
+
+// Bulk lookup from numeric ID to string state key for that state key.
+// Takes an array of strings as the query parameter.
+const bulkSelectEventStateKeySQL = "" +
+	"SELECT event_state_key, event_state_key_nid FROM roomserver_event_state_keys" +
+	" WHERE event_state_key_nid = ANY($1)"
+
 type eventStateKeyStatements struct {
 	insertEventStateKeyNIDStmt     *sql.Stmt
 	selectEventStateKeyNIDStmt     *sql.Stmt
+	selectEventStateKeyStmt        *sql.Stmt
 	bulkSelectEventStateKeyNIDStmt *sql.Stmt
+	bulkSelectEventStateKeyStmt    *sql.Stmt
 }
 
 func (s *eventStateKeyStatements) prepare(db *sql.DB) (err error) {
@@ -72,7 +84,9 @@ func (s *eventStateKeyStatements) prepare(db *sql.DB) (err error) {
 	return statementList{
 		{&s.insertEventStateKeyNIDStmt, insertEventStateKeyNIDSQL},
 		{&s.selectEventStateKeyNIDStmt, selectEventStateKeyNIDSQL},
+		{&s.selectEventStateKeyStmt, selectEventStateKeySQL},
 		{&s.bulkSelectEventStateKeyNIDStmt, bulkSelectEventStateKeyNIDSQL},
+		{&s.bulkSelectEventStateKeyStmt, bulkSelectEventStateKeySQL},
 	}.prepare(db)
 }
 
@@ -114,3 +128,36 @@ func (s *eventStateKeyStatements) bulkSelectEventStateKeyNID(eventStateKeys []st
 	}
 	return result, nil
 }
+
+func (s *eventStateKeyStatements) selectEventStateKey(txn *sql.Tx, eventStateKeyNID types.EventStateKeyNID) (string, error) {
+	var eventStateKey string
+	stmt := s.selectEventStateKeyStmt
+	if txn != nil {
+		stmt = txn.Stmt(stmt)
+	}
+	err := stmt.QueryRow(eventStateKeyNID).Scan(&eventStateKey)
+	return eventStateKey, err
+}
+
+func (s *eventStateKeyStatements) bulkSelectEventStateKey(eventStateKeyNIDs []types.EventStateKeyNID) (map[types.EventStateKeyNID]string, error) {
+	var nIDs pq.Int64Array
+	for i := range eventStateKeyNIDs {
+		nIDs[i] = int64(eventStateKeyNIDs[i])
+	}
+	rows, err := s.bulkSelectEventStateKeyStmt.Query(nIDs)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	result := make(map[types.EventStateKeyNID]string, len(eventStateKeyNIDs))
+	for rows.Next() {
+		var stateKey string
+		var stateKeyNID int64
+		if err := rows.Scan(&stateKey, &stateKeyNID); err != nil {
+			return nil, err
+		}
+		result[types.EventStateKeyNID(stateKeyNID)] = stateKey
+	}
+	return result, nil
+}

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

@@ -46,11 +46,16 @@ CREATE TABLE IF NOT EXISTS roomserver_membership (
 	-- The state the user is in within this room.
 	-- Default value is "membershipStateLeaveOrBan"
 	membership_nid BIGINT NOT NULL DEFAULT 1,
-	-- The ID of the "join" membership event.
-	-- This ID is updated if the join event gets updated (e.g. profile update).
-	-- This column is set to NULL if the user hasn't joined the room yet, e.g.
-	-- if the user was invited but hasn't joined yet.
-	event_id TEXT,
+	-- The numeric ID of the membership event.
+	-- It refers to the join membership event if the membership_nid is join (3),
+	-- and to the leave/ban membership event if the membership_nid is leave or
+	-- ban (1).
+	-- If the membership_nid is invite (2) and the user has been in the room
+	-- before, it will refer to the previous leave/ban membership event, and will
+	-- be equals to 0 (its default) if the user never joined the room before.
+	-- This NID is updated if the join event gets updated (e.g. profile update),
+	-- or if the user leaves/joins the room.
+	event_nid BIGINT NOT NULL DEFAULT 0,
 	UNIQUE (room_nid, target_nid)
 );
 `
@@ -62,18 +67,33 @@ const insertMembershipSQL = "" +
 	" VALUES ($1, $2)" +
 	" ON CONFLICT DO NOTHING"
 
+const selectMembershipFromRoomAndTargetSQL = "" +
+	"SELECT membership_nid, event_nid FROM roomserver_membership" +
+	" WHERE room_nid = $1 AND target_nid = $2"
+
+const selectMembershipsFromRoomAndMembershipSQL = "" +
+	"SELECT event_nid FROM roomserver_membership" +
+	" WHERE room_nid = $1 AND membership_nid = $2"
+
+const selectMembershipsFromRoomSQL = "" +
+	"SELECT membership_nid, event_nid FROM roomserver_membership" +
+	" WHERE room_nid = $1"
+
 const selectMembershipForUpdateSQL = "" +
 	"SELECT membership_nid FROM roomserver_membership" +
 	" WHERE room_nid = $1 AND target_nid = $2 FOR UPDATE"
 
 const updateMembershipSQL = "" +
-	"UPDATE roomserver_membership SET sender_nid = $3, membership_nid = $4, event_id = $5" +
+	"UPDATE roomserver_membership SET sender_nid = $3, membership_nid = $4, event_nid = $5" +
 	" WHERE room_nid = $1 AND target_nid = $2"
 
 type membershipStatements struct {
-	insertMembershipStmt          *sql.Stmt
-	selectMembershipForUpdateStmt *sql.Stmt
-	updateMembershipStmt          *sql.Stmt
+	insertMembershipStmt                       *sql.Stmt
+	selectMembershipForUpdateStmt              *sql.Stmt
+	selectMembershipFromRoomAndTargetStmt      *sql.Stmt
+	selectMembershipsFromRoomAndMembershipStmt *sql.Stmt
+	selectMembershipsFromRoomStmt              *sql.Stmt
+	updateMembershipStmt                       *sql.Stmt
 }
 
 func (s *membershipStatements) prepare(db *sql.DB) (err error) {
@@ -85,6 +105,9 @@ func (s *membershipStatements) prepare(db *sql.DB) (err error) {
 	return statementList{
 		{&s.insertMembershipStmt, insertMembershipSQL},
 		{&s.selectMembershipForUpdateStmt, selectMembershipForUpdateSQL},
+		{&s.selectMembershipFromRoomAndTargetStmt, selectMembershipFromRoomAndTargetSQL},
+		{&s.selectMembershipsFromRoomAndMembershipStmt, selectMembershipsFromRoomAndMembershipSQL},
+		{&s.selectMembershipsFromRoomStmt, selectMembershipsFromRoomSQL},
 		{&s.updateMembershipStmt, updateMembershipSQL},
 	}.prepare(db)
 }
@@ -105,17 +128,59 @@ func (s *membershipStatements) selectMembershipForUpdate(
 	return
 }
 
+func (s *membershipStatements) selectMembershipFromRoomAndTarget(
+	roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
+) (eventNID types.EventNID, membership membershipState, err error) {
+	err = s.selectMembershipFromRoomAndTargetStmt.QueryRow(
+		roomNID, targetUserNID,
+	).Scan(&membership, &eventNID)
+	return
+}
+
+func (s *membershipStatements) selectMembershipsFromRoom(
+	roomNID types.RoomNID,
+) (eventNIDs map[types.EventNID]membershipState, err error) {
+	rows, err := s.selectMembershipsFromRoomStmt.Query(roomNID)
+	if err != nil {
+		return
+	}
+
+	eventNIDs = make(map[types.EventNID]membershipState)
+	for rows.Next() {
+		var eNID types.EventNID
+		var membership membershipState
+		if err = rows.Scan(&membership, &eNID); err != nil {
+			return
+		}
+		eventNIDs[eNID] = membership
+	}
+	return
+}
+func (s *membershipStatements) selectMembershipsFromRoomAndMembership(
+	roomNID types.RoomNID, membership membershipState,
+) (eventNIDs []types.EventNID, err error) {
+	rows, err := s.selectMembershipsFromRoomAndMembershipStmt.Query(roomNID, membership)
+	if err != nil {
+		return
+	}
+
+	for rows.Next() {
+		var eNID types.EventNID
+		if err = rows.Scan(&eNID); err != nil {
+			return
+		}
+		eventNIDs = append(eventNIDs, eNID)
+	}
+	return
+}
+
 func (s *membershipStatements) updateMembership(
 	txn *sql.Tx, roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
 	senderUserNID types.EventStateKeyNID, membership membershipState,
-	eventID string,
+	eventNID types.EventNID,
 ) error {
-	eID := sql.NullString{
-		String: eventID,
-		Valid:  len(eventID) > 0,
-	}
 	_, err := txn.Stmt(s.updateMembershipStmt).Exec(
-		roomNID, targetUserNID, senderUserNID, membership, eID,
+		roomNID, targetUserNID, senderUserNID, membership, eventNID,
 	)
 	return err
 }

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

@@ -435,7 +435,7 @@ func (u *membershipUpdater) SetToInvite(event gomatrixserverlib.Event) (bool, er
 	}
 	if u.membership != membershipStateInvite {
 		if err = u.d.statements.updateMembership(
-			u.txn, u.roomNID, u.targetUserNID, senderUserNID, membershipStateInvite, "",
+			u.txn, u.roomNID, u.targetUserNID, senderUserNID, membershipStateInvite, 0,
 		); err != nil {
 			return false, err
 		}
@@ -462,9 +462,15 @@ func (u *membershipUpdater) SetToJoin(senderUserID string, eventID string, isUpd
 		}
 	}
 
+	// Lookup the NID of the new join event
+	nIDs, err := u.d.EventNIDs([]string{eventID})
+	if err != nil {
+		return nil, err
+	}
+
 	if u.membership != membershipStateJoin || isUpdate {
 		if err = u.d.statements.updateMembership(
-			u.txn, u.roomNID, u.targetUserNID, senderUserNID, membershipStateJoin, eventID,
+			u.txn, u.roomNID, u.targetUserNID, senderUserNID, membershipStateJoin, nIDs[eventID],
 		); err != nil {
 			return nil, err
 		}
@@ -474,7 +480,7 @@ func (u *membershipUpdater) SetToJoin(senderUserID string, eventID string, isUpd
 }
 
 // SetToLeave implements types.MembershipUpdater
-func (u *membershipUpdater) SetToLeave(senderUserID string) ([]string, error) {
+func (u *membershipUpdater) SetToLeave(senderUserID string, eventID string) ([]string, error) {
 	senderUserNID, err := u.d.assignStateKeyNID(u.txn, senderUserID)
 	if err != nil {
 		return nil, err
@@ -485,9 +491,16 @@ func (u *membershipUpdater) SetToLeave(senderUserID string) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	// Lookup the NID of the new leave event
+	nIDs, err := u.d.EventNIDs([]string{eventID})
+	if err != nil {
+		return nil, err
+	}
+
 	if u.membership != membershipStateLeaveOrBan {
 		if err = u.d.statements.updateMembership(
-			u.txn, u.roomNID, u.targetUserNID, senderUserNID, membershipStateLeaveOrBan, "",
+			u.txn, u.roomNID, u.targetUserNID, senderUserNID, membershipStateLeaveOrBan, nIDs[eventID],
 		); err != nil {
 			return nil, err
 		}
@@ -495,6 +508,53 @@ func (u *membershipUpdater) SetToLeave(senderUserID string) ([]string, error) {
 	return inviteEventIDs, nil
 }
 
+// GetMembershipEvents returns an array containing the join events for all
+// members in a room as requested by a given user. If the user is currently in
+// the room, returns the room's current members, if not returns an empty array
+// TODO: in this case, send the list of members as it was when the user left
+// If the user requesting the list of members has never been in the room, returns
+// nil.
+// If there was an issue retrieving the events, returns an error.
+func (d *Database) GetMembershipEvents(roomNID types.RoomNID, requestSenderUserID string) (events []types.Event, err error) {
+	txn, err := d.db.Begin()
+	if err != nil {
+		return
+	}
+
+	requestSenderUserNID, err := d.assignStateKeyNID(txn, requestSenderUserID)
+	if err != nil {
+		return
+	}
+
+	_, senderMembership, err := d.statements.selectMembershipFromRoomAndTarget(roomNID, requestSenderUserNID)
+	if err == sql.ErrNoRows {
+		// The user has never been a member of that room
+		return nil, nil
+	} else if err != nil {
+		return
+	}
+
+	if senderMembership == membershipStateJoin {
+		// 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
+		// TODO: Send the list of joined member as it was when the user left
+		//       We cannot do this using only the memberships database, as it
+		//       only stores the latest join event NID for a given target user.
+		//       The solution would be to build the state of a room after before
+		//       the leave event and extract a members list from it.
+	}
+
+	return
+}
+
 type transaction struct {
 	txn *sql.Tx
 }

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

@@ -198,7 +198,7 @@ type MembershipUpdater interface {
 	SetToJoin(senderUserID string, eventID string, isUpdate bool) (inviteEventIDs []string, err error)
 	// Set the state to leave.
 	// Returns a list of invite event IDs that this state change retired.
-	SetToLeave(senderUserID string) (inviteEventIDs []string, err error)
+	SetToLeave(senderUserID string, eventID string) (inviteEventIDs []string, err error)
 	// Implements Transaction so it can be committed or rolledback.
 	Transaction
 }