Adding upstream version 3.10.8.

Signed-off-by: Daniel Baumann <daniel@debian.org>

options/factory.go

@@ -0,0 +1,35 @@
+// Copyright Earl Warren <contact@earl-warren.org>
+// Copyright Loïc Dachary <loic@dachary.org>
+// SPDX-License-Identifier: MIT
+
+package options
+
+import (
+	"fmt"
+	"strings"
+)
+
+type (
+	Factory   func() Interface
+	Factories map[string]Factory
+)
+
+var factories = make(Factories, 10)
+
+func GetFactories() Factories {
+	return factories
+}
+
+func RegisterFactory(name string, factory Factory) {
+	name = strings.ToLower(name)
+	factories[name] = factory
+}
+
+func GetFactory(name string) Factory {
+	name = strings.ToLower(name)
+	factory, ok := factories[name]
+	if !ok {
+		panic(fmt.Errorf("no options factory registered for %s", name))
+	}
+	return factory
+}