Event relations (#2790)

This adds support for tracking `m.relates_to`, as well as adding support
for the various `/room/{roomID}/relations/...` endpoints to the CS API.

syncapi/storage/postgres/relations_table.go

@@ -0,0 +1,158 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package postgres
+
+import (
+	"context"
+	"database/sql"
+
+	"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"
+)
+
+const relationsSchema = `
+CREATE SEQUENCE IF NOT EXISTS syncapi_relation_id;
+
+CREATE TABLE IF NOT EXISTS syncapi_relations (
+	id BIGINT PRIMARY KEY DEFAULT nextval('syncapi_relation_id'),
+	room_id TEXT NOT NULL,
+	event_id TEXT NOT NULL,
+	child_event_id TEXT NOT NULL,
+	child_event_type TEXT NOT NULL,
+	rel_type TEXT NOT NULL,
+	CONSTRAINT syncapi_relations_unique UNIQUE (room_id, event_id, child_event_id, rel_type)
+);
+`
+
+const insertRelationSQL = "" +
+	"INSERT INTO syncapi_relations (" +
+	"  room_id, event_id, child_event_id, child_event_type, rel_type" +
+	") VALUES ($1, $2, $3, $4, $5) " +
+	" ON CONFLICT DO NOTHING"
+
+const deleteRelationSQL = "" +
+	"DELETE FROM syncapi_relations WHERE room_id = $1 AND child_event_id = $2"
+
+const selectRelationsInRangeAscSQL = "" +
+	"SELECT id, child_event_id, rel_type FROM syncapi_relations" +
+	" WHERE room_id = $1 AND event_id = $2" +
+	" AND ( $3 = '' OR rel_type = $3 )" +
+	" AND ( $4 = '' OR child_event_type = $4 )" +
+	" AND id > $5 AND id <= $6" +
+	" ORDER BY id ASC LIMIT $7"
+
+const selectRelationsInRangeDescSQL = "" +
+	"SELECT id, child_event_id, rel_type FROM syncapi_relations" +
+	" WHERE room_id = $1 AND event_id = $2" +
+	" AND ( $3 = '' OR rel_type = $3 )" +
+	" AND ( $4 = '' OR child_event_type = $4 )" +
+	" AND id >= $5 AND id < $6" +
+	" ORDER BY id DESC LIMIT $7"
+
+const selectMaxRelationIDSQL = "" +
+	"SELECT COALESCE(MAX(id), 0) FROM syncapi_relations"
+
+type relationsStatements struct {
+	insertRelationStmt             *sql.Stmt
+	selectRelationsInRangeAscStmt  *sql.Stmt
+	selectRelationsInRangeDescStmt *sql.Stmt
+	deleteRelationStmt             *sql.Stmt
+	selectMaxRelationIDStmt        *sql.Stmt
+}
+
+func NewPostgresRelationsTable(db *sql.DB) (tables.Relations, error) {
+	s := &relationsStatements{}
+	_, err := db.Exec(relationsSchema)
+	if err != nil {
+		return nil, err
+	}
+	return s, sqlutil.StatementList{
+		{&s.insertRelationStmt, insertRelationSQL},
+		{&s.selectRelationsInRangeAscStmt, selectRelationsInRangeAscSQL},
+		{&s.selectRelationsInRangeDescStmt, selectRelationsInRangeDescSQL},
+		{&s.deleteRelationStmt, deleteRelationSQL},
+		{&s.selectMaxRelationIDStmt, selectMaxRelationIDSQL},
+	}.Prepare(db)
+}
+
+func (s *relationsStatements) InsertRelation(
+	ctx context.Context, txn *sql.Tx, roomID, eventID, childEventID, childEventType, relType string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.insertRelationStmt).ExecContext(
+		ctx, roomID, eventID, childEventID, childEventType, relType,
+	)
+	return
+}
+
+func (s *relationsStatements) DeleteRelation(
+	ctx context.Context, txn *sql.Tx, roomID, childEventID string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.deleteRelationStmt)
+	_, err := stmt.ExecContext(
+		ctx, roomID, childEventID,
+	)
+	return err
+}
+
+// SelectRelationsInRange returns a map rel_type -> []child_event_id
+func (s *relationsStatements) SelectRelationsInRange(
+	ctx context.Context, txn *sql.Tx, roomID, eventID, relType, eventType string,
+	r types.Range, limit int,
+) (map[string][]types.RelationEntry, types.StreamPosition, error) {
+	var lastPos types.StreamPosition
+	var stmt *sql.Stmt
+	if r.Backwards {
+		stmt = sqlutil.TxStmt(txn, s.selectRelationsInRangeDescStmt)
+	} else {
+		stmt = sqlutil.TxStmt(txn, s.selectRelationsInRangeAscStmt)
+	}
+	rows, err := stmt.QueryContext(ctx, roomID, eventID, relType, eventType, r.Low(), r.High(), limit)
+	if err != nil {
+		return nil, lastPos, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectRelationsInRange: rows.close() failed")
+	result := map[string][]types.RelationEntry{}
+	var (
+		id           types.StreamPosition
+		childEventID string
+		relationType string
+	)
+	for rows.Next() {
+		if err = rows.Scan(&id, &childEventID, &relationType); err != nil {
+			return nil, lastPos, err
+		}
+		if id > lastPos {
+			lastPos = id
+		}
+		result[relationType] = append(result[relationType], types.RelationEntry{
+			Position: id,
+			EventID:  childEventID,
+		})
+	}
+	if lastPos == 0 {
+		lastPos = r.To
+	}
+	return result, lastPos, rows.Err()
+}
+
+func (s *relationsStatements) SelectMaxRelationID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	stmt := sqlutil.TxStmt(txn, s.selectMaxRelationIDStmt)
+	err = stmt.QueryRowContext(ctx).Scan(&id)
+	return
+}