added custom filter options

filter.go

@@ -0,0 +1,44 @@
+// Copyright (C) 2019 Marius Schellenberger
+
+package authdav
+
+import (
+	"errors"
+	"path/filepath"
+	"strings"
+)
+
+type Matcher func(path string) bool
+
+type Filter interface {
+	Filter(path string) error
+}
+
+var ErrMacOSFilter = errors.New("authdav: MacOS filter: access denied")
+
+type MacOSFilter struct {
+	match []Matcher
+}
+
+func NewMacOSFilter() *MacOSFilter {
+	return &MacOSFilter{
+		match: []Matcher{
+			func(p string) {
+				return p == ".DS_Store"
+			},
+			func(p string) {
+				return strings.HasPrefix(p, "._")
+			},
+		},
+	}
+}
+
+func (f *MacOSFilter) Filter(path string) error {
+	_, f := filepath.Split(path)
+	for _, m := range f.match {
+		if m(f) {
+			return ErrMacOSFilter
+		}
+	}
+	return nil
+}