Add heroes to the room summary (#2373)

* Implement room summary heroes

* Add passing tests

* Move MembershipCount to addRoomSummary

* Add comments, close Statement

5 files changed, 81 insertions, 14 deletions

diff --git a/syncapi/storage/interface.go b/syncapi/storage/interface.go
index 14cb08a5..0fea88da 100644
--- a/syncapi/storage/interface.go
+++ b/syncapi/storage/interface.go
@@ -39,6 +39,7 @@ type Database interface {
 	GetStateDeltas(ctx context.Context, device *userapi.Device, r types.Range, userID string, stateFilter *gomatrixserverlib.StateFilter) ([]types.StateDelta, []string, error)
 	RoomIDsWithMembership(ctx context.Context, userID string, membership string) ([]string, error)
 	MembershipCount(ctx context.Context, roomID, membership string, pos types.StreamPosition) (int, error)
+	GetRoomHeroes(ctx context.Context, roomID, userID string, memberships []string) ([]string, error)
 
 	RecentEvents(ctx context.Context, roomID string, r types.Range, eventFilter *gomatrixserverlib.RoomEventFilter, chronologicalOrder bool, onlySyncEvents bool) ([]types.StreamEvent, bool, error)
 
diff --git a/syncapi/storage/postgres/memberships_table.go b/syncapi/storage/postgres/memberships_table.go
index 39fa656c..8c049977 100644
--- a/syncapi/storage/postgres/memberships_table.go
+++ b/syncapi/storage/postgres/memberships_table.go
@@ -19,6 +19,8 @@ import (
 	"database/sql"
 	"fmt"
 
+	"github.com/lib/pq"
+	"github.com/matrix-org/dendrite/internal"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/syncapi/storage/tables"
 	"github.com/matrix-org/dendrite/syncapi/types"
@@ -61,9 +63,13 @@ const selectMembershipCountSQL = "" +
 	" SELECT DISTINCT ON (room_id, user_id) room_id, user_id, membership FROM syncapi_memberships WHERE room_id = $1 AND stream_pos <= $2 ORDER BY room_id, user_id, stream_pos DESC" +
 	") t WHERE t.membership = $3"
 
+const selectHeroesSQL = "" +
+	"SELECT user_id FROM syncapi_memberships WHERE room_id = $1 AND user_id != $2 AND membership = ANY($3) LIMIT 5"
+
 type membershipsStatements struct {
 	upsertMembershipStmt      *sql.Stmt
 	selectMembershipCountStmt *sql.Stmt
+	selectHeroesStmt          *sql.Stmt
 }
 
 func NewPostgresMembershipsTable(db *sql.DB) (tables.Memberships, error) {
@@ -72,13 +78,11 @@ func NewPostgresMembershipsTable(db *sql.DB) (tables.Memberships, error) {
 	if err != nil {
 		return nil, err
 	}
-	if s.upsertMembershipStmt, err = db.Prepare(upsertMembershipSQL); err != nil {
-		return nil, err
-	}
-	if s.selectMembershipCountStmt, err = db.Prepare(selectMembershipCountSQL); err != nil {
-		return nil, err
-	}
-	return s, nil
+	return s, sqlutil.StatementList{
+		{&s.upsertMembershipStmt, upsertMembershipSQL},
+		{&s.selectMembershipCountStmt, selectMembershipCountSQL},
+		{&s.selectHeroesStmt, selectHeroesSQL},
+	}.Prepare(db)
 }
 
 func (s *membershipsStatements) UpsertMembership(
@@ -108,3 +112,23 @@ func (s *membershipsStatements) SelectMembershipCount(
 	err = stmt.QueryRowContext(ctx, roomID, pos, membership).Scan(&count)
 	return
 }
+
+func (s *membershipsStatements) SelectHeroes(
+	ctx context.Context, txn *sql.Tx, roomID, userID string, memberships []string,
+) (heroes []string, err error) {
+	stmt := sqlutil.TxStmt(txn, s.selectHeroesStmt)
+	var rows *sql.Rows
+	rows, err = stmt.QueryContext(ctx, roomID, userID, pq.StringArray(memberships))
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectHeroes: rows.close() failed")
+	var hero string
+	for rows.Next() {
+		if err = rows.Scan(&hero); err != nil {
+			return
+		}
+		heroes = append(heroes, hero)
+	}
+	return heroes, rows.Err()
+}
diff --git a/syncapi/storage/shared/syncserver.go b/syncapi/storage/shared/syncserver.go
index 2143fd67..3c431db4 100644
--- a/syncapi/storage/shared/syncserver.go
+++ b/syncapi/storage/shared/syncserver.go
@@ -124,6 +124,10 @@ func (d *Database) MembershipCount(ctx context.Context, roomID, membership strin
 	return d.Memberships.SelectMembershipCount(ctx, nil, roomID, membership, pos)
 }
 
+func (d *Database) GetRoomHeroes(ctx context.Context, roomID, userID string, memberships []string) ([]string, error) {
+	return d.Memberships.SelectHeroes(ctx, nil, roomID, userID, memberships)
+}
+
 func (d *Database) RecentEvents(ctx context.Context, roomID string, r types.Range, eventFilter *gomatrixserverlib.RoomEventFilter, chronologicalOrder bool, onlySyncEvents bool) ([]types.StreamEvent, bool, error) {
 	return d.OutputEvents.SelectRecentEvents(ctx, nil, roomID, r, eventFilter, chronologicalOrder, onlySyncEvents)
 }
diff --git a/syncapi/storage/sqlite3/memberships_table.go b/syncapi/storage/sqlite3/memberships_table.go
index 9f3530cc..e4daa99c 100644
--- a/syncapi/storage/sqlite3/memberships_table.go
+++ b/syncapi/storage/sqlite3/memberships_table.go
@@ -18,7 +18,9 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
+	"strings"
 
+	"github.com/matrix-org/dendrite/internal"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/syncapi/storage/tables"
 	"github.com/matrix-org/dendrite/syncapi/types"
@@ -61,10 +63,14 @@ const selectMembershipCountSQL = "" +
 	" SELECT * FROM syncapi_memberships WHERE room_id = $1 AND stream_pos <= $2 GROUP BY user_id HAVING(max(stream_pos))" +
 	") t WHERE t.membership = $3"
 
+const selectHeroesSQL = "" +
+	"SELECT DISTINCT user_id FROM syncapi_memberships WHERE room_id = $1 AND user_id != $2 AND membership IN ($3) LIMIT 5"
+
 type membershipsStatements struct {
 	db                        *sql.DB
 	upsertMembershipStmt      *sql.Stmt
 	selectMembershipCountStmt *sql.Stmt
+	//selectHeroesStmt          *sql.Stmt - prepared at runtime due to variadic
 }
 
 func NewSqliteMembershipsTable(db *sql.DB) (tables.Memberships, error) {
@@ -75,13 +81,11 @@ func NewSqliteMembershipsTable(db *sql.DB) (tables.Memberships, error) {
 	if err != nil {
 		return nil, err
 	}
-	if s.upsertMembershipStmt, err = db.Prepare(upsertMembershipSQL); err != nil {
-		return nil, err
-	}
-	if s.selectMembershipCountStmt, err = db.Prepare(selectMembershipCountSQL); err != nil {
-		return nil, err
-	}
-	return s, nil
+	return s, sqlutil.StatementList{
+		{&s.upsertMembershipStmt, upsertMembershipSQL},
+		{&s.selectMembershipCountStmt, selectMembershipCountSQL},
+		// {&s.selectHeroesStmt, selectHeroesSQL}, - prepared at runtime due to variadic
+	}.Prepare(db)
 }
 
 func (s *membershipsStatements) UpsertMembership(
@@ -111,3 +115,36 @@ func (s *membershipsStatements) SelectMembershipCount(
 	err = stmt.QueryRowContext(ctx, roomID, pos, membership).Scan(&count)
 	return
 }
+
+func (s *membershipsStatements) SelectHeroes(
+	ctx context.Context, txn *sql.Tx, roomID, userID string, memberships []string,
+) (heroes []string, err error) {
+	stmtSQL := strings.Replace(selectHeroesSQL, "($3)", sqlutil.QueryVariadicOffset(len(memberships), 2), 1)
+	stmt, err := s.db.PrepareContext(ctx, stmtSQL)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, stmt, "SelectHeroes: stmt.close() failed")
+	params := []interface{}{
+		roomID, userID,
+	}
+	for _, membership := range memberships {
+		params = append(params, membership)
+	}
+
+	stmt = sqlutil.TxStmt(txn, stmt)
+	var rows *sql.Rows
+	rows, err = stmt.QueryContext(ctx, params...)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectHeroes: rows.close() failed")
+	var hero string
+	for rows.Next() {
+		if err = rows.Scan(&hero); err != nil {
+			return
+		}
+		heroes = append(heroes, hero)
+	}
+	return heroes, rows.Err()
+}
diff --git a/syncapi/storage/tables/interface.go b/syncapi/storage/tables/interface.go
index 993e2022..ac713dd5 100644
--- a/syncapi/storage/tables/interface.go
+++ b/syncapi/storage/tables/interface.go
@@ -170,6 +170,7 @@ type Receipts interface {
 type Memberships interface {
 	UpsertMembership(ctx context.Context, txn *sql.Tx, event *gomatrixserverlib.HeaderedEvent, streamPos, topologicalPos types.StreamPosition) error
 	SelectMembershipCount(ctx context.Context, txn *sql.Tx, roomID, membership string, pos types.StreamPosition) (count int, err error)
+	SelectHeroes(ctx context.Context, txn *sql.Tx, roomID, userID string, memberships []string) (heroes []string, err error)
 }
 
 type NotificationData interface {