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// Copyright 2017-2018 New Vector Ltd
// Copyright 2019-2020 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 sqlite3
import (
"context"
"database/sql"
"github.com/matrix-org/dendrite/common"
)
const roomSchema = `
CREATE TABLE IF NOT EXISTS federationsender_rooms (
-- The string ID of the room
room_id TEXT PRIMARY KEY,
-- The most recent event state by the room server.
-- We can use this to tell if our view of the room state has become
-- desynchronised.
last_event_id TEXT NOT NULL
);`
const insertRoomSQL = "" +
"INSERT INTO federationsender_rooms (room_id, last_event_id) VALUES ($1, '')" +
" ON CONFLICT DO NOTHING"
const selectRoomForUpdateSQL = "" +
"SELECT last_event_id FROM federationsender_rooms WHERE room_id = $1"
const updateRoomSQL = "" +
"UPDATE federationsender_rooms SET last_event_id = $2 WHERE room_id = $1"
type roomStatements struct {
insertRoomStmt *sql.Stmt
selectRoomForUpdateStmt *sql.Stmt
updateRoomStmt *sql.Stmt
}
func (s *roomStatements) prepare(db *sql.DB) (err error) {
_, err = db.Exec(roomSchema)
if err != nil {
return
}
if s.insertRoomStmt, err = db.Prepare(insertRoomSQL); err != nil {
return
}
if s.selectRoomForUpdateStmt, err = db.Prepare(selectRoomForUpdateSQL); err != nil {
return
}
if s.updateRoomStmt, err = db.Prepare(updateRoomSQL); err != nil {
return
}
return
}
// insertRoom inserts the room if it didn't already exist.
// If the room didn't exist then last_event_id is set to the empty string.
func (s *roomStatements) insertRoom(
ctx context.Context, txn *sql.Tx, roomID string,
) error {
_, err := common.TxStmt(txn, s.insertRoomStmt).ExecContext(ctx, roomID)
return err
}
// selectRoomForUpdate locks the row for the room and returns the last_event_id.
// The row must already exist in the table. Callers can ensure that the row
// exists by calling insertRoom first.
func (s *roomStatements) selectRoomForUpdate(
ctx context.Context, txn *sql.Tx, roomID string,
) (string, error) {
var lastEventID string
stmt := common.TxStmt(txn, s.selectRoomForUpdateStmt)
err := stmt.QueryRowContext(ctx, roomID).Scan(&lastEventID)
if err != nil {
return "", err
}
return lastEventID, nil
}
// updateRoom updates the last_event_id for the room. selectRoomForUpdate should
// have already been called earlier within the transaction.
func (s *roomStatements) updateRoom(
ctx context.Context, txn *sql.Tx, roomID, lastEventID string,
) error {
stmt := common.TxStmt(txn, s.updateRoomStmt)
_, err := stmt.ExecContext(ctx, roomID, lastEventID)
return err
}
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