add vendoring

vendor/maunium.net/go/mautrix/util/dbutil/connlog.go

@@ -0,0 +1,102 @@
+// Copyright (c) 2022 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package dbutil
+
+import (
+	"context"
+	"database/sql"
+	"time"
+)
+
+// LoggingExecable is a wrapper for anything with database Exec methods (i.e. sql.Conn, sql.DB and sql.Tx)
+// that can preprocess queries (e.g. replacing $ with ? on SQLite) and log query durations.
+type LoggingExecable struct {
+	UnderlyingExecable Execable
+	db                 *Database
+}
+
+func (le *LoggingExecable) ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
+	start := time.Now()
+	query = le.db.mutateQuery(query)
+	res, err := le.UnderlyingExecable.ExecContext(ctx, query, args...)
+	le.db.Log.QueryTiming(ctx, "Exec", query, args, time.Since(start))
+	return res, err
+}
+
+func (le *LoggingExecable) QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error) {
+	start := time.Now()
+	query = le.db.mutateQuery(query)
+	rows, err := le.UnderlyingExecable.QueryContext(ctx, query, args...)
+	le.db.Log.QueryTiming(ctx, "Query", query, args, time.Since(start))
+	return rows, err
+}
+
+func (le *LoggingExecable) QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row {
+	start := time.Now()
+	query = le.db.mutateQuery(query)
+	row := le.UnderlyingExecable.QueryRowContext(ctx, query, args...)
+	le.db.Log.QueryTiming(ctx, "QueryRow", query, args, time.Since(start))
+	return row
+}
+
+func (le *LoggingExecable) Exec(query string, args ...interface{}) (sql.Result, error) {
+	return le.ExecContext(context.Background(), query, args...)
+}
+
+func (le *LoggingExecable) Query(query string, args ...interface{}) (*sql.Rows, error) {
+	return le.QueryContext(context.Background(), query, args...)
+}
+
+func (le *LoggingExecable) QueryRow(query string, args ...interface{}) *sql.Row {
+	return le.QueryRowContext(context.Background(), query, args...)
+}
+
+// loggingDB is a wrapper for LoggingExecable that allows access to BeginTx.
+//
+// While LoggingExecable has a pointer to the database and could use BeginTx, it's not technically safe since
+// the LoggingExecable could be for a transaction (where BeginTx wouldn't make sense).
+type loggingDB struct {
+	LoggingExecable
+}
+
+func (ld *loggingDB) BeginTx(ctx context.Context, opts *sql.TxOptions) (*LoggingTxn, error) {
+	start := time.Now()
+	tx, err := ld.db.RawDB.BeginTx(ctx, opts)
+	ld.db.Log.QueryTiming(ctx, "Begin", "", nil, time.Since(start))
+	if err != nil {
+		return nil, err
+	}
+	return &LoggingTxn{
+		LoggingExecable: LoggingExecable{UnderlyingExecable: tx, db: ld.db},
+		UnderlyingTx:    tx,
+		ctx:             ctx,
+	}, nil
+}
+
+func (ld *loggingDB) Begin() (*LoggingTxn, error) {
+	return ld.BeginTx(context.Background(), nil)
+}
+
+type LoggingTxn struct {
+	LoggingExecable
+	UnderlyingTx *sql.Tx
+	ctx          context.Context
+}
+
+func (lt *LoggingTxn) Commit() error {
+	start := time.Now()
+	err := lt.UnderlyingTx.Commit()
+	lt.db.Log.QueryTiming(lt.ctx, "Commit", "", nil, time.Since(start))
+	return err
+}
+
+func (lt *LoggingTxn) Rollback() error {
+	start := time.Now()
+	err := lt.UnderlyingTx.Rollback()
+	lt.db.Log.QueryTiming(lt.ctx, "Rollback", "", nil, time.Since(start))
+	return err
+}

vendor/maunium.net/go/mautrix/util/dbutil/database.go

@@ -0,0 +1,206 @@
+// Copyright (c) 2022 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package dbutil
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"regexp"
+	"strings"
+	"time"
+
+	"maunium.net/go/mautrix/bridge/bridgeconfig"
+)
+
+type Dialect int
+
+const (
+	DialectUnknown Dialect = iota
+	Postgres
+	SQLite
+)
+
+func (dialect Dialect) String() string {
+	switch dialect {
+	case Postgres:
+		return "postgres"
+	case SQLite:
+		return "sqlite3"
+	default:
+		return ""
+	}
+}
+
+func ParseDialect(engine string) (Dialect, error) {
+	switch strings.ToLower(engine) {
+	case "postgres", "postgresql":
+		return Postgres, nil
+	case "sqlite3", "sqlite", "litestream":
+		return SQLite, nil
+	default:
+		return DialectUnknown, fmt.Errorf("unknown dialect '%s'", engine)
+	}
+}
+
+type Scannable interface {
+	Scan(...interface{}) error
+}
+
+// Expected implementations of Scannable
+var (
+	_ Scannable = (*sql.Row)(nil)
+	_ Scannable = (*sql.Rows)(nil)
+)
+
+type ContextExecable interface {
+	ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error)
+	QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error)
+	QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row
+}
+
+type Execable interface {
+	ContextExecable
+	Exec(query string, args ...interface{}) (sql.Result, error)
+	Query(query string, args ...interface{}) (*sql.Rows, error)
+	QueryRow(query string, args ...interface{}) *sql.Row
+}
+
+type Transaction interface {
+	Execable
+	Commit() error
+	Rollback() error
+}
+
+// Expected implementations of Execable
+var (
+	_ Execable        = (*sql.Tx)(nil)
+	_ Execable        = (*sql.DB)(nil)
+	_ Execable        = (*LoggingExecable)(nil)
+	_ Transaction     = (*LoggingTxn)(nil)
+	_ ContextExecable = (*sql.Conn)(nil)
+)
+
+type Database struct {
+	loggingDB
+	RawDB        *sql.DB
+	Owner        string
+	VersionTable string
+	Log          DatabaseLogger
+	Dialect      Dialect
+	UpgradeTable UpgradeTable
+
+	IgnoreForeignTables       bool
+	IgnoreUnsupportedDatabase bool
+}
+
+var positionalParamPattern = regexp.MustCompile(`\$(\d+)`)
+
+func (db *Database) mutateQuery(query string) string {
+	switch db.Dialect {
+	case SQLite:
+		return positionalParamPattern.ReplaceAllString(query, "?$1")
+	default:
+		return query
+	}
+}
+
+func (db *Database) Child(versionTable string, upgradeTable UpgradeTable, log DatabaseLogger) *Database {
+	if log == nil {
+		log = db.Log
+	}
+	return &Database{
+		RawDB:        db.RawDB,
+		loggingDB:    db.loggingDB,
+		Owner:        "",
+		VersionTable: versionTable,
+		UpgradeTable: upgradeTable,
+		Log:          log,
+		Dialect:      db.Dialect,
+
+		IgnoreForeignTables:       true,
+		IgnoreUnsupportedDatabase: db.IgnoreUnsupportedDatabase,
+	}
+}
+
+func NewWithDB(db *sql.DB, rawDialect string) (*Database, error) {
+	dialect, err := ParseDialect(rawDialect)
+	if err != nil {
+		return nil, err
+	}
+	wrappedDB := &Database{
+		RawDB:   db,
+		Dialect: dialect,
+		Log:     NoopLogger,
+
+		IgnoreForeignTables: true,
+		VersionTable:        "version",
+	}
+	wrappedDB.loggingDB.UnderlyingExecable = db
+	wrappedDB.loggingDB.db = wrappedDB
+	return wrappedDB, nil
+}
+
+func NewWithDialect(uri, rawDialect string) (*Database, error) {
+	db, err := sql.Open(rawDialect, uri)
+	if err != nil {
+		return nil, err
+	}
+	return NewWithDB(db, rawDialect)
+}
+
+func (db *Database) Configure(cfg bridgeconfig.DatabaseConfig) error {
+	db.RawDB.SetMaxOpenConns(cfg.MaxOpenConns)
+	db.RawDB.SetMaxIdleConns(cfg.MaxIdleConns)
+	if len(cfg.ConnMaxIdleTime) > 0 {
+		maxIdleTimeDuration, err := time.ParseDuration(cfg.ConnMaxIdleTime)
+		if err != nil {
+			return fmt.Errorf("failed to parse max_conn_idle_time: %w", err)
+		}
+		db.RawDB.SetConnMaxIdleTime(maxIdleTimeDuration)
+	}
+	if len(cfg.ConnMaxLifetime) > 0 {
+		maxLifetimeDuration, err := time.ParseDuration(cfg.ConnMaxLifetime)
+		if err != nil {
+			return fmt.Errorf("failed to parse max_conn_idle_time: %w", err)
+		}
+		db.RawDB.SetConnMaxLifetime(maxLifetimeDuration)
+	}
+	return nil
+}
+
+func NewFromConfig(owner string, cfg bridgeconfig.DatabaseConfig, logger DatabaseLogger) (*Database, error) {
+	dialect, err := ParseDialect(cfg.Type)
+	if err != nil {
+		return nil, err
+	}
+	conn, err := sql.Open(cfg.Type, cfg.URI)
+	if err != nil {
+		return nil, err
+	}
+	if logger == nil {
+		logger = NoopLogger
+	}
+	wrappedDB := &Database{
+		RawDB: conn,
+
+		Owner:   owner,
+		Dialect: dialect,
+
+		Log: logger,
+
+		IgnoreForeignTables: true,
+		VersionTable:        "version",
+	}
+	err = wrappedDB.Configure(cfg)
+	if err != nil {
+		return nil, err
+	}
+	wrappedDB.loggingDB.UnderlyingExecable = conn
+	wrappedDB.loggingDB.db = wrappedDB
+	return wrappedDB, nil
+}

vendor/maunium.net/go/mautrix/util/dbutil/log.go

@@ -0,0 +1,129 @@
+package dbutil
+
+import (
+	"context"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/rs/zerolog"
+	"maunium.net/go/maulogger/v2"
+)
+
+type DatabaseLogger interface {
+	QueryTiming(ctx context.Context, method, query string, args []interface{}, duration time.Duration)
+	WarnUnsupportedVersion(current, latest int)
+	PrepareUpgrade(current, latest int)
+	DoUpgrade(from, to int, message string)
+	// Deprecated: legacy warning method, return errors instead
+	Warn(msg string, args ...interface{})
+}
+
+type noopLogger struct{}
+
+var NoopLogger DatabaseLogger = &noopLogger{}
+
+func (n noopLogger) WarnUnsupportedVersion(_, _ int)      {}
+func (n noopLogger) PrepareUpgrade(_, _ int)              {}
+func (n noopLogger) DoUpgrade(_, _ int, _ string)         {}
+func (n noopLogger) Warn(msg string, args ...interface{}) {}
+
+func (n noopLogger) QueryTiming(_ context.Context, _, _ string, _ []interface{}, _ time.Duration) {}
+
+type mauLogger struct {
+	l maulogger.Logger
+}
+
+func MauLogger(log maulogger.Logger) DatabaseLogger {
+	return &mauLogger{l: log}
+}
+
+func (m mauLogger) WarnUnsupportedVersion(current, latest int) {
+	m.l.Warnfln("Unsupported database schema version: currently on v%d, latest known: v%d - continuing anyway", current, latest)
+}
+
+func (m mauLogger) PrepareUpgrade(current, latest int) {
+	m.l.Infofln("Database currently on v%d, latest: v%d", current, latest)
+}
+
+func (m mauLogger) DoUpgrade(from, to int, message string) {
+	m.l.Infofln("Upgrading database from v%d to v%d: %s", from, to, message)
+}
+
+func (m mauLogger) QueryTiming(_ context.Context, method, query string, _ []interface{}, duration time.Duration) {
+	if duration > 1*time.Second {
+		m.l.Warnfln("%s(%s) took %.3f seconds", method, query, duration.Seconds())
+	}
+}
+
+func (m mauLogger) Warn(msg string, args ...interface{}) {
+	m.l.Warnfln(msg, args...)
+}
+
+type zeroLogger struct {
+	l *zerolog.Logger
+}
+
+func ZeroLogger(log zerolog.Logger) DatabaseLogger {
+	return ZeroLoggerPtr(&log)
+}
+
+func ZeroLoggerPtr(log *zerolog.Logger) DatabaseLogger {
+	return &zeroLogger{l: log}
+}
+
+func (z zeroLogger) WarnUnsupportedVersion(current, latest int) {
+	z.l.Warn().
+		Int("current_db_version", current).
+		Int("latest_known_version", latest).
+		Msg("Unsupported database schema version, continuing anyway")
+}
+
+func (z zeroLogger) PrepareUpgrade(current, latest int) {
+	evt := z.l.Info().
+		Int("current_db_version", current).
+		Int("latest_known_version", latest)
+	if current == latest {
+		evt.Msg("Database is up to date")
+	} else {
+		evt.Msg("Preparing to update database schema")
+	}
+}
+
+func (z zeroLogger) DoUpgrade(from, to int, message string) {
+	z.l.Info().
+		Int("from", from).
+		Int("to", to).
+		Str("description", message).
+		Msg("Upgrading database")
+}
+
+var whitespaceRegex = regexp.MustCompile(`\s+`)
+
+func (z zeroLogger) QueryTiming(ctx context.Context, method, query string, args []interface{}, duration time.Duration) {
+	log := zerolog.Ctx(ctx)
+	if log.GetLevel() == zerolog.Disabled {
+		log = z.l
+	}
+	if log.GetLevel() != zerolog.TraceLevel && duration < 1*time.Second {
+		return
+	}
+	query = strings.TrimSpace(whitespaceRegex.ReplaceAllLiteralString(query, " "))
+	log.Trace().
+		Int64("duration_µs", duration.Microseconds()).
+		Str("method", method).
+		Str("query", query).
+		Interface("query_args", args).
+		Msg("Query")
+	if duration >= 1*time.Second {
+		log.Warn().
+			Float64("duration_seconds", duration.Seconds()).
+			Str("method", method).
+			Str("query", query).
+			Msg("Query took long")
+	}
+}
+
+func (z zeroLogger) Warn(msg string, args ...interface{}) {
+	z.l.Warn().Msgf(msg, args...)
+}

vendor/maunium.net/go/mautrix/util/dbutil/samples/01-sample.sql

@@ -0,0 +1,21 @@
+-- v0 -> v3: Sample revision jump
+CREATE TABLE foo (
+	-- only: postgres
+	key BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
+	-- only: sqlite
+	key INTEGER PRIMARY KEY,
+
+	data JSONB NOT NULL
+);
+
+-- only: sqlite until "end only"
+CREATE TRIGGER test AFTER INSERT ON foo WHEN NEW.data->>'action' = 'delete' BEGIN
+	DELETE FROM test WHERE key <= NEW.data->>'index';
+END;
+-- end only sqlite
+-- only: postgres until "end only"
+CREATE FUNCTION delete_data() RETURNS TRIGGER LANGUAGE plpgsql AS $$ BEGIN
+	DELETE FROM test WHERE key <= NEW.data->>'index';
+	RETURN NEW;
+END $$;
+-- end only postgres

vendor/maunium.net/go/mautrix/util/dbutil/samples/output/01-postgres.sql

@@ -0,0 +1,11 @@
+CREATE TABLE foo (
+	key BIGINT PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
+
+	data JSONB NOT NULL
+);
+
+CREATE FUNCTION delete_data() RETURNS TRIGGER LANGUAGE plpgsql AS $$ BEGIN
+	DELETE FROM test WHERE key <= NEW.data->>'index';
+	RETURN NEW;
+END $$;
+-- end only postgres

vendor/maunium.net/go/mautrix/util/dbutil/samples/output/01-sqlite3.sql

@@ -0,0 +1,10 @@
+CREATE TABLE foo (
+	key INTEGER PRIMARY KEY,
+
+	data JSONB NOT NULL
+);
+
+CREATE TRIGGER test AFTER INSERT ON foo WHEN NEW.data->>'action' = 'delete' BEGIN
+	DELETE FROM test WHERE key <= NEW.data->>'index';
+END;
+-- end only sqlite

vendor/maunium.net/go/mautrix/util/dbutil/upgrades.go

@@ -0,0 +1,154 @@
+// Copyright (c) 2022 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package dbutil
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+)
+
+type upgradeFunc func(Transaction, *Database) error
+
+type upgrade struct {
+	message string
+	fn      upgradeFunc
+
+	upgradesTo int
+}
+
+var ErrUnsupportedDatabaseVersion = fmt.Errorf("unsupported database schema version")
+var ErrForeignTables = fmt.Errorf("the database contains foreign tables")
+var ErrNotOwned = fmt.Errorf("the database is owned by")
+
+func (db *Database) getVersion() (int, error) {
+	_, err := db.Exec(fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s (version INTEGER)", db.VersionTable))
+	if err != nil {
+		return -1, err
+	}
+
+	version := 0
+	err = db.QueryRow(fmt.Sprintf("SELECT version FROM %s LIMIT 1", db.VersionTable)).Scan(&version)
+	if err != nil && !errors.Is(err, sql.ErrNoRows) {
+		return -1, err
+	}
+	return version, nil
+}
+
+const tableExistsPostgres = "SELECT EXISTS(SELECT 1 FROM information_schema.tables WHERE table_name=$1)"
+const tableExistsSQLite = "SELECT EXISTS(SELECT 1 FROM sqlite_master WHERE type='table' AND tbl_name=$1)"
+
+func (db *Database) tableExists(table string) (exists bool, err error) {
+	if db.Dialect == SQLite {
+		err = db.QueryRow(tableExistsSQLite, table).Scan(&exists)
+	} else if db.Dialect == Postgres {
+		err = db.QueryRow(tableExistsPostgres, table).Scan(&exists)
+	}
+	return
+}
+
+func (db *Database) tableExistsNoError(table string) bool {
+	exists, err := db.tableExists(table)
+	if err != nil {
+		panic(fmt.Errorf("failed to check if table exists: %w", err))
+	}
+	return exists
+}
+
+const createOwnerTable = `
+CREATE TABLE IF NOT EXISTS database_owner (
+	key   INTEGER PRIMARY KEY DEFAULT 0,
+	owner TEXT NOT NULL
+)
+`
+
+func (db *Database) checkDatabaseOwner() error {
+	var owner string
+	if !db.IgnoreForeignTables {
+		if db.tableExistsNoError("state_groups_state") {
+			return fmt.Errorf("%w (found state_groups_state, likely belonging to Synapse)", ErrForeignTables)
+		} else if db.tableExistsNoError("roomserver_rooms") {
+			return fmt.Errorf("%w (found roomserver_rooms, likely belonging to Dendrite)", ErrForeignTables)
+		}
+	}
+	if db.Owner == "" {
+		return nil
+	}
+	if _, err := db.Exec(createOwnerTable); err != nil {
+		return fmt.Errorf("failed to ensure database owner table exists: %w", err)
+	} else if err = db.QueryRow("SELECT owner FROM database_owner WHERE key=0").Scan(&owner); errors.Is(err, sql.ErrNoRows) {
+		_, err = db.Exec("INSERT INTO database_owner (key, owner) VALUES (0, $1)", db.Owner)
+		if err != nil {
+			return fmt.Errorf("failed to insert database owner: %w", err)
+		}
+	} else if err != nil {
+		return fmt.Errorf("failed to check database owner: %w", err)
+	} else if owner != db.Owner {
+		return fmt.Errorf("%w %s", ErrNotOwned, owner)
+	}
+	return nil
+}
+
+func (db *Database) setVersion(tx Transaction, version int) error {
+	_, err := tx.Exec(fmt.Sprintf("DELETE FROM %s", db.VersionTable))
+	if err != nil {
+		return err
+	}
+	_, err = tx.Exec(fmt.Sprintf("INSERT INTO %s (version) VALUES ($1)", db.VersionTable), version)
+	return err
+}
+
+func (db *Database) Upgrade() error {
+	err := db.checkDatabaseOwner()
+	if err != nil {
+		return err
+	}
+
+	version, err := db.getVersion()
+	if err != nil {
+		return err
+	}
+
+	if version > len(db.UpgradeTable) {
+		if db.IgnoreUnsupportedDatabase {
+			db.Log.WarnUnsupportedVersion(version, len(db.UpgradeTable))
+			return nil
+		}
+		return fmt.Errorf("%w: currently on v%d, latest known: v%d", ErrUnsupportedDatabaseVersion, version, len(db.UpgradeTable))
+	}
+
+	db.Log.PrepareUpgrade(version, len(db.UpgradeTable))
+	logVersion := version
+	for version < len(db.UpgradeTable) {
+		upgradeItem := db.UpgradeTable[version]
+		if upgradeItem.fn == nil {
+			version++
+			continue
+		}
+		db.Log.DoUpgrade(logVersion, upgradeItem.upgradesTo, upgradeItem.message)
+		var tx Transaction
+		tx, err = db.Begin()
+		if err != nil {
+			return err
+		}
+		err = upgradeItem.fn(tx, db)
+		if err != nil {
+			return err
+		}
+		version = upgradeItem.upgradesTo
+		logVersion = version
+		err = db.setVersion(tx, version)
+		if err != nil {
+			return err
+		}
+		err = tx.Commit()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

vendor/maunium.net/go/mautrix/util/dbutil/upgradetable.go

@@ -0,0 +1,255 @@
+// Copyright (c) 2022 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package dbutil
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io/fs"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+type UpgradeTable []upgrade
+
+func (ut *UpgradeTable) extend(toSize int) {
+	if cap(*ut) >= toSize {
+		*ut = (*ut)[:toSize]
+	} else {
+		resized := make([]upgrade, toSize)
+		copy(resized, *ut)
+		*ut = resized
+	}
+}
+
+func (ut *UpgradeTable) Register(from, to int, message string, fn upgradeFunc) {
+	if from < 0 {
+		from += to
+	}
+	if from < 0 {
+		panic("invalid from value in UpgradeTable.Register() call")
+	}
+	upg := upgrade{message: message, fn: fn, upgradesTo: to}
+	if len(*ut) == from {
+		*ut = append(*ut, upg)
+		return
+	} else if len(*ut) < from {
+		ut.extend(from + 1)
+	} else if (*ut)[from].fn != nil {
+		panic(fmt.Errorf("tried to override upgrade at %d ('%s') with '%s'", from, (*ut)[from].message, upg.message))
+	}
+	(*ut)[from] = upg
+}
+
+// Syntax is either
+//
+//	-- v0 -> v1: Message
+//
+// or
+//
+//	-- v1: Message
+var upgradeHeaderRegex = regexp.MustCompile(`^-- (?:v(\d+) -> )?v(\d+): (.+)$`)
+
+func parseFileHeader(file []byte) (from, to int, message string, lines [][]byte, err error) {
+	lines = bytes.Split(file, []byte("\n"))
+	if len(lines) < 2 {
+		err = errors.New("upgrade file too short")
+		return
+	}
+	var maybeFrom int
+	match := upgradeHeaderRegex.FindSubmatch(lines[0])
+	lines = lines[1:]
+	if match == nil {
+		err = errors.New("header not found")
+	} else if len(match) != 4 {
+		err = errors.New("unexpected number of items in regex match")
+	} else if maybeFrom, err = strconv.Atoi(string(match[1])); len(match[1]) > 0 && err != nil {
+		err = fmt.Errorf("invalid source version: %w", err)
+	} else if to, err = strconv.Atoi(string(match[2])); err != nil {
+		err = fmt.Errorf("invalid target version: %w", err)
+	} else {
+		if len(match[1]) > 0 {
+			from = maybeFrom
+		} else {
+			from = -1
+		}
+		message = string(match[3])
+	}
+	return
+}
+
+// To limit the next line to one dialect:
+//
+//	-- only: postgres
+//
+// To limit the next N lines:
+//
+//	-- only: sqlite for next 123 lines
+//
+// If the single-line limit is on the second line of the file, the whole file is limited to that dialect.
+var dialectLineFilter = regexp.MustCompile(`^\s*-- only: (postgres|sqlite)(?: for next (\d+) lines| until "(end) only")?`)
+
+// Constants used to make parseDialectFilter clearer
+const (
+	skipUntilEndTag = -1
+	skipNothing     = 0
+	skipCurrentLine = 1
+	skipNextLine    = 2
+)
+
+func (db *Database) parseDialectFilter(line []byte) (int, error) {
+	match := dialectLineFilter.FindSubmatch(line)
+	if match == nil {
+		return skipNothing, nil
+	}
+	dialect, err := ParseDialect(string(match[1]))
+	if err != nil {
+		return skipNothing, err
+	} else if dialect == db.Dialect {
+		// Skip the dialect filter line
+		return skipCurrentLine, nil
+	} else if bytes.Equal(match[3], []byte("end")) {
+		return skipUntilEndTag, nil
+	} else if len(match[2]) == 0 {
+		// Skip the dialect filter and the next line
+		return skipNextLine, nil
+	} else {
+		// Parse number of lines to skip, add 1 for current line
+		lineCount, err := strconv.Atoi(string(match[2]))
+		if err != nil {
+			return skipNothing, fmt.Errorf("invalid line count '%s': %w", match[2], err)
+		}
+		return skipCurrentLine + lineCount, nil
+	}
+}
+
+var endLineFilter = regexp.MustCompile(`^\s*-- end only (postgres|sqlite)$`)
+
+func (db *Database) filterSQLUpgrade(lines [][]byte) (string, error) {
+	output := make([][]byte, 0, len(lines))
+	for i := 0; i < len(lines); i++ {
+		skipLines, err := db.parseDialectFilter(lines[i])
+		if err != nil {
+			return "", err
+		} else if skipLines > 0 {
+			// Current line is implicitly skipped, so reduce one here
+			i += skipLines - 1
+		} else if skipLines == skipUntilEndTag {
+			startedAt := i
+			startedAtMatch := dialectLineFilter.FindSubmatch(lines[startedAt])
+			for ; i < len(lines); i++ {
+				if match := endLineFilter.FindSubmatch(lines[i]); match != nil {
+					if !bytes.Equal(match[1], startedAtMatch[1]) {
+						return "", fmt.Errorf(`unexpected end tag %q for %q start at line %d`, string(match[0]), string(startedAtMatch[1]), startedAt)
+					}
+					break
+				}
+			}
+			if i == len(lines) {
+				return "", fmt.Errorf(`didn't get end tag matching start %q at line %d`, string(startedAtMatch[1]), startedAt)
+			}
+		} else {
+			output = append(output, lines[i])
+		}
+	}
+	return string(bytes.Join(output, []byte("\n"))), nil
+}
+
+func sqlUpgradeFunc(fileName string, lines [][]byte) upgradeFunc {
+	return func(tx Transaction, db *Database) error {
+		if skip, err := db.parseDialectFilter(lines[0]); err == nil && skip == skipNextLine {
+			return nil
+		} else if upgradeSQL, err := db.filterSQLUpgrade(lines); err != nil {
+			panic(fmt.Errorf("failed to parse upgrade %s: %w", fileName, err))
+		} else {
+			_, err = tx.Exec(upgradeSQL)
+			return err
+		}
+	}
+}
+
+func splitSQLUpgradeFunc(sqliteData, postgresData string) upgradeFunc {
+	return func(tx Transaction, database *Database) (err error) {
+		switch database.Dialect {
+		case SQLite:
+			_, err = tx.Exec(sqliteData)
+		case Postgres:
+			_, err = tx.Exec(postgresData)
+		default:
+			err = fmt.Errorf("unknown dialect %s", database.Dialect)
+		}
+		return
+	}
+}
+
+func parseSplitSQLUpgrade(name string, fs fullFS, skipNames map[string]struct{}) (from, to int, message string, fn upgradeFunc) {
+	postgresName := fmt.Sprintf("%s.postgres.sql", name)
+	sqliteName := fmt.Sprintf("%s.sqlite.sql", name)
+	skipNames[postgresName] = struct{}{}
+	skipNames[sqliteName] = struct{}{}
+	postgresData, err := fs.ReadFile(postgresName)
+	if err != nil {
+		panic(err)
+	}
+	sqliteData, err := fs.ReadFile(sqliteName)
+	if err != nil {
+		panic(err)
+	}
+	from, to, message, _, err = parseFileHeader(postgresData)
+	if err != nil {
+		panic(fmt.Errorf("failed to parse header in %s: %w", postgresName, err))
+	}
+	sqliteFrom, sqliteTo, sqliteMessage, _, err := parseFileHeader(sqliteData)
+	if err != nil {
+		panic(fmt.Errorf("failed to parse header in %s: %w", sqliteName, err))
+	}
+	if from != sqliteFrom || to != sqliteTo {
+		panic(fmt.Errorf("mismatching versions in postgres and sqlite versions of %s: %d/%d -> %d/%d", name, from, sqliteFrom, to, sqliteTo))
+	} else if message != sqliteMessage {
+		panic(fmt.Errorf("mismatching message in postgres and sqlite versions of %s: %q != %q", name, message, sqliteMessage))
+	}
+	fn = splitSQLUpgradeFunc(string(sqliteData), string(postgresData))
+	return
+}
+
+type fullFS interface {
+	fs.ReadFileFS
+	fs.ReadDirFS
+}
+
+var splitFileNameRegex = regexp.MustCompile(`^(.+)\.(postgres|sqlite)\.sql$`)
+
+func (ut *UpgradeTable) RegisterFS(fs fullFS) {
+	ut.RegisterFSPath(fs, ".")
+}
+
+func (ut *UpgradeTable) RegisterFSPath(fs fullFS, dir string) {
+	files, err := fs.ReadDir(dir)
+	if err != nil {
+		panic(err)
+	}
+	skipNames := map[string]struct{}{}
+	for _, file := range files {
+		if file.IsDir() || !strings.HasSuffix(file.Name(), ".sql") {
+			// do nothing
+		} else if _, skip := skipNames[file.Name()]; skip {
+			// also do nothing
+		} else if splitName := splitFileNameRegex.FindStringSubmatch(file.Name()); splitName != nil {
+			from, to, message, fn := parseSplitSQLUpgrade(splitName[1], fs, skipNames)
+			ut.Register(from, to, message, fn)
+		} else if data, err := fs.ReadFile(filepath.Join(dir, file.Name())); err != nil {
+			panic(err)
+		} else if from, to, message, lines, err := parseFileHeader(data); err != nil {
+			panic(fmt.Errorf("failed to parse header in %s: %w", file.Name(), err))
+		} else {
+			ut.Register(from, to, message, sqlUpgradeFunc(file.Name(), lines))
+		}
+	}
+}