pkg/flags: add "StringSlice"

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

pkg/flags/string_slice.go

@@ -0,0 +1,44 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package flags
+
+import (
+	"sort"
+	"strings"
+)
+
+// StringSlice wraps "sort.StringSlice".
+type StringSlice sort.StringSlice
+
+// Set parses a command line set of strings, separated by comma.
+func (ss *StringSlice) Set(s string) error {
+	*ss = strings.Split(s, ",")
+	return nil
+}
+
+func (ss *StringSlice) String() string { return strings.Join(*ss, ",") }
+
+// NewStringSlice implements string slice as flag.Value interface.
+// Given value is to be separated by comma.
+func NewStringSlice(s string) (ss *StringSlice) {
+	if s == "" {
+		return &StringSlice{}
+	}
+	ss = new(StringSlice)
+	if err := ss.Set(s); err != nil {
+		plog.Panicf("new StringSlice should never fail: %v", err)
+	}
+	return ss
+}

pkg/flags/string_slice_test.go

@@ -0,0 +1,37 @@
+// Copyright 2018 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package flags
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestStringSlice(t *testing.T) {
+	tests := []struct {
+		s   string
+		exp []string
+	}{
+		{s: "a,b,c", exp: []string{"a", "b", "c"}},
+		{s: "a, b,c", exp: []string{"a", " b", "c"}},
+		{s: "", exp: []string{}},
+	}
+	for i := range tests {
+		ss := []string(*NewStringSlice(tests[i].s))
+		if !reflect.DeepEqual(tests[i].exp, ss) {
+			t.Fatalf("#%d: expected %q, got %q", i, tests[i].exp, ss)
+		}
+	}
+}