initial commit

util/implements.go

@@ -0,0 +1,45 @@
+package util
+
+import (
+	"reflect"
+)
+
+// Implements get reflect.Zero(T) and (o).Implements(T)
+func Implements[T any](o any) (T, bool) {
+	iface := reflect.TypeOf((*T)(nil)).Elem()
+
+	reflectType := reflect.TypeOf(o)
+
+	if alreadyReflectType, ok := o.(reflect.Type); ok {
+		reflectType = alreadyReflectType
+		o = reflect.Zero(reflectType).Interface()
+	} else if alreadyReflectValue, ok := o.(reflect.Value); ok {
+		reflectType = alreadyReflectValue.Type()
+		o = alreadyReflectValue.Interface()
+	}
+
+	if reflectType.Implements(iface) {
+		if reflectType.Kind() == reflect.Interface {
+			return *reflect.New(iface).Interface().(*T), true
+		}
+		return o.(T), true
+	} else {
+		return *reflect.New(iface).Interface().(*T), false
+	}
+}
+
+// PointerImplements get reflect.New(T) and (&o).Implements(T)
+func PointerImplements[I any](o any) (reflect.Value, bool) {
+	iface := reflect.TypeOf((*I)(nil)).Elem()
+
+	reflectType := reflect.TypeOf(&o)
+	if alreadyReflectType, ok := o.(reflect.Type); ok {
+		reflectType = reflect.PointerTo(alreadyReflectType)
+	} else if alreadyReflectValue, ok := o.(reflect.Value); ok {
+		reflectType = reflect.PointerTo(alreadyReflectValue.Type())
+	}
+
+	reflectValue := reflect.New(reflectType.Elem())
+
+	return reflectValue, reflectType.Implements(iface)
+}