refactor to mautrix 0.17.x; update deps

vendor/go.mau.fi/util/dbutil/iter.go

@@ -0,0 +1,72 @@
+// Copyright (c) 2023 Sumner Evans
+//
+// 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
+
+// RowIter is a wrapper for [Rows] that allows conveniently iterating over rows
+// with a predefined scanner function.
+type RowIter[T any] interface {
+	// Iter iterates over the rows and calls the given function for each row.
+	//
+	// If the function returns false, the iteration is stopped.
+	// If the function returns an error, the iteration is stopped and the error is
+	// returned.
+	Iter(func(T) (bool, error)) error
+
+	// AsList collects all rows into a slice.
+	AsList() ([]T, error)
+}
+
+type rowIterImpl[T any] struct {
+	Rows
+	ConvertRow func(Scannable) (T, error)
+}
+
+// NewRowIter creates a new RowIter from the given Rows and scanner function.
+func NewRowIter[T any](rows Rows, convertFn func(Scannable) (T, error)) RowIter[T] {
+	return &rowIterImpl[T]{Rows: rows, ConvertRow: convertFn}
+}
+
+func ScanSingleColumn[T any](rows Scannable) (val T, err error) {
+	err = rows.Scan(&val)
+	return
+}
+
+type NewableDataStruct[T any] interface {
+	DataStruct[T]
+	New() T
+}
+
+func ScanDataStruct[T NewableDataStruct[T]](rows Scannable) (T, error) {
+	var val T
+	return val.New().Scan(rows)
+}
+
+func (i *rowIterImpl[T]) Iter(fn func(T) (bool, error)) error {
+	if i == nil || i.Rows == nil {
+		return nil
+	}
+	defer i.Rows.Close()
+
+	for i.Rows.Next() {
+		if item, err := i.ConvertRow(i.Rows); err != nil {
+			return err
+		} else if cont, err := fn(item); err != nil {
+			return err
+		} else if !cont {
+			break
+		}
+	}
+	return i.Rows.Err()
+}
+
+func (i *rowIterImpl[T]) AsList() (list []T, err error) {
+	err = i.Iter(func(item T) (bool, error) {
+		list = append(list, item)
+		return true, nil
+	})
+	return
+}