bisync: implementation #5164

Fixes #118

Co-authored-by: Chris Nelson <stuff@cjnaz.com>

cmd/bisync/bilib/names.go

@@ -0,0 +1,61 @@
+package bilib
+
+import (
+	"bytes"
+	"io/ioutil"
+	"sort"
+	"strconv"
+)
+
+// Names comprises a set of file names
+type Names map[string]interface{}
+
+// ToNames converts string slice to a set of names
+func ToNames(list []string) Names {
+	ns := Names{}
+	for _, f := range list {
+		ns.Add(f)
+	}
+	return ns
+}
+
+// Add adds new file name to the set
+func (ns Names) Add(name string) {
+	ns[name] = nil
+}
+
+// Has checks whether given name is present in the set
+func (ns Names) Has(name string) bool {
+	_, ok := ns[name]
+	return ok
+}
+
+// NotEmpty checks whether set is not empty
+func (ns Names) NotEmpty() bool {
+	return len(ns) > 0
+}
+
+// ToList converts name set to string slice
+func (ns Names) ToList() []string {
+	list := []string{}
+	for file := range ns {
+		list = append(list, file)
+	}
+	sort.Strings(list)
+	return list
+}
+
+// Save saves name set in a text file
+func (ns Names) Save(path string) error {
+	return SaveList(ns.ToList(), path)
+}
+
+// SaveList saves file name list in a text file
+func SaveList(list []string, path string) error {
+	buf := &bytes.Buffer{}
+	for _, s := range list {
+		_, _ = buf.WriteString(strconv.Quote(s))
+		_ = buf.WriteByte('\n')
+	}
+	return ioutil.WriteFile(path, buf.Bytes(), PermSecure)
+}