config: add List type

fs/config/config_list.go

@@ -0,0 +1,94 @@
+package config
+
+import (
+	"bytes"
+	"encoding/csv"
+	"fmt"
+)
+
+// CommaSepList is a comma separated config value
+// It uses the encoding/csv rules for quoting and escaping
+type CommaSepList []string
+
+// SpaceSepList is a space separated config value
+// It uses the encoding/csv rules for quoting and escaping
+type SpaceSepList []string
+
+type genericList []string
+
+func (l CommaSepList) String() string {
+	return genericList(l).string(',')
+}
+
+// Set the List entries
+func (l *CommaSepList) Set(s string) error {
+	return (*genericList)(l).set(',', []byte(s))
+}
+
+// Type of the value
+func (CommaSepList) Type() string {
+	return "[]string"
+}
+
+// Scan implements the fmt.Scanner interface
+func (l *CommaSepList) Scan(s fmt.ScanState, ch rune) error {
+	return (*genericList)(l).scan(',', s, ch)
+}
+
+func (l SpaceSepList) String() string {
+	return genericList(l).string(' ')
+}
+
+// Set the List entries
+func (l *SpaceSepList) Set(s string) error {
+	return (*genericList)(l).set(' ', []byte(s))
+}
+
+// Type of the value
+func (SpaceSepList) Type() string {
+	return "[]string"
+}
+
+// Scan implements the fmt.Scanner interface
+func (l *SpaceSepList) Scan(s fmt.ScanState, ch rune) error {
+	return (*genericList)(l).scan(' ', s, ch)
+}
+
+func (gl genericList) string(sep rune) string {
+	var buf bytes.Buffer
+	w := csv.NewWriter(&buf)
+	w.Comma = sep
+	err := w.Write(gl)
+	if err != nil {
+		// can only happen if w.Comma is invalid
+		panic(err)
+	}
+	w.Flush()
+	return string(bytes.TrimSpace(buf.Bytes()))
+}
+
+func (gl *genericList) set(sep rune, b []byte) error {
+	if len(b) == 0 {
+		*gl = nil
+		return nil
+	}
+	r := csv.NewReader(bytes.NewReader(b))
+	r.Comma = sep
+
+	record, err := r.Read()
+	switch _err := err.(type) {
+	case nil:
+		*gl = record
+	case *csv.ParseError:
+		err = _err.Err // remove line numbers from the error message
+	}
+	return err
+}
+
+func (gl *genericList) scan(sep rune, s fmt.ScanState, ch rune) error {
+	token, err := s.Token(true, func(rune) bool { return true })
+	if err != nil {
+		return err
+	}
+	return gl.set(sep, bytes.TrimSpace(token))
+}

fs/config/config_list_test.go

@@ -0,0 +1,87 @@
+package config
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func must(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+func ExampleSpaceSepList() {
+	for _, s := range []string{
+		`remotea:test/dir remoteb:`,
+		`"remotea:test/space dir" remoteb:`,
+		`"remotea:test/quote""dir" remoteb:`,
+	} {
+		var l SpaceSepList
+		must(l.Set(s))
+		fmt.Printf("%#v\n", l)
+	}
+	// Output:
+	// config.SpaceSepList{"remotea:test/dir", "remoteb:"}
+	// config.SpaceSepList{"remotea:test/space dir", "remoteb:"}
+	// config.SpaceSepList{"remotea:test/quote\"dir", "remoteb:"}
+}
+
+func ExampleCommaSepList() {
+	for _, s := range []string{
+		`remotea:test/dir,remoteb:`,
+		`"remotea:test/space dir",remoteb:`,
+		`"remotea:test/quote""dir",remoteb:`,
+	} {
+		var l CommaSepList
+		must(l.Set(s))
+		fmt.Printf("%#v\n", l)
+	}
+	// Output:
+	// config.CommaSepList{"remotea:test/dir", "remoteb:"}
+	// config.CommaSepList{"remotea:test/space dir", "remoteb:"}
+	// config.CommaSepList{"remotea:test/quote\"dir", "remoteb:"}
+}
+
+func TestSpaceSepListSet(t *testing.T) {
+	type tc struct {
+		in  string
+		out SpaceSepList
+		err string
+	}
+	tests := []tc{
+		{``, nil, ""},
+		{`\`, SpaceSepList{`\`}, ""},
+		{`\\`, SpaceSepList{`\\`}, ""},
+		{`potato`, SpaceSepList{`potato`}, ""},
+		{`po\tato`, SpaceSepList{`po\tato`}, ""},
+		{`potato\`, SpaceSepList{`potato\`}, ""},
+		{`'potato`, SpaceSepList{`'potato`}, ""},
+		{`pot'ato`, SpaceSepList{`pot'ato`}, ""},
+		{`potato'`, SpaceSepList{`potato'`}, ""},
+		{`"potato"`, SpaceSepList{`potato`}, ""},
+		{`'potato'`, SpaceSepList{`'potato'`}, ""},
+		{`potato apple`, SpaceSepList{`potato`, `apple`}, ""},
+		{`potato\ apple`, SpaceSepList{`potato\`, `apple`}, ""},
+		{`"potato  apple"`, SpaceSepList{`potato  apple`}, ""},
+		{`"potato'apple"`, SpaceSepList{`potato'apple`}, ""},
+		{`"potato''apple"`, SpaceSepList{`potato''apple`}, ""},
+		{`"potato' 'apple"`, SpaceSepList{`potato' 'apple`}, ""},
+		{`potato="apple"`, nil, `bare " in non-quoted-field`},
+		{`apple "potato`, nil, "extraneous"},
+		{`apple pot"ato`, nil, "bare \" in non-quoted-field"},
+		{`potato"`, nil, "bare \" in non-quoted-field"},
+	}
+	for _, tc := range tests {
+		var l SpaceSepList
+		err := l.Set(tc.in)
+		if tc.err == "" {
+			require.NoErrorf(t, err, "input: %q", tc.in)
+		} else {
+			require.Containsf(t, err.Error(), tc.err, "input: %q", tc.in)
+		}
+		require.Equalf(t, tc.out, l, "input: %q", tc.in)
+	}
+}