goprotobuf: Support encoding.TextMarshaler and encoding.TextUnmarshaler.
LGTM=r
R=r
CC=golang-codereviews
https://codereview.appspot.com/65740044
diff --git a/proto/text.go b/proto/text.go
index f8cb9c9..b4a5dbb 100644
--- a/proto/text.go
+++ b/proto/text.go
@@ -74,6 +74,13 @@
w writer
}
+// textMarshaler is implemented by Messages that can marshal themsleves.
+// It is identical to encoding.TextMarshaler, introduced in go 1.2,
+// which will eventually replace it.
+type textMarshaler interface {
+ MarshalText() (text []byte, err error)
+}
+
func (w *textWriter) WriteString(s string) (n int, err error) {
if !strings.Contains(s, "\n") {
if !w.compact && w.complete {
@@ -342,7 +349,15 @@
}
}
w.indent()
- if err := writeStruct(w, v); err != nil {
+ if tm, ok := v.Interface().(textMarshaler); ok {
+ text, err := tm.MarshalText()
+ if err != nil {
+ return err
+ }
+ if _, err = w.Write(text); err != nil {
+ return err
+ }
+ } else if err := writeStruct(w, v); err != nil {
return err
}
w.unindent()
@@ -629,6 +644,19 @@
compact: compact,
}
+ if tm, ok := pb.(textMarshaler); ok {
+ text, err := tm.MarshalText()
+ if err != nil {
+ return err
+ }
+ if _, err = aw.Write(text); err != nil {
+ return err
+ }
+ if bw != nil {
+ return bw.Flush()
+ }
+ return nil
+ }
// Dereference the received pointer so we don't have outer < and >.
v := reflect.Indirect(val)
if err := writeStruct(aw, v); err != nil {
@@ -642,7 +670,9 @@
// MarshalText writes a given protocol buffer in text format.
// The only errors returned are from w.
-func MarshalText(w io.Writer, pb Message) error { return marshalText(w, pb, false) }
+func MarshalText(w io.Writer, pb Message) error {
+ return marshalText(w, pb, false)
+}
// MarshalTextString is the same as MarshalText, but returns the string directly.
func MarshalTextString(pb Message) string {
diff --git a/proto/text_parser.go b/proto/text_parser.go
index 13827f6..4d4167c 100644
--- a/proto/text_parser.go
+++ b/proto/text_parser.go
@@ -43,6 +43,13 @@
"unicode/utf8"
)
+// textUnmarshaler is implemented by Messages that can unmarshal themsleves.
+// It is identical to encoding.TextUnmarshaler, introduced in go 1.2,
+// which will eventually replace it.
+type textUnmarshaler interface {
+ UnmarshalText(text []byte) error
+}
+
type ParseError struct {
Message string
Line int // 1-based line number
@@ -643,6 +650,7 @@
default:
return p.errorf("expected '{' or '<', found %q", tok.value)
}
+ // TODO: Handle nested messages which implement textUnmarshaler.
return p.readStruct(fv, terminator)
case reflect.Uint32:
if x, err := strconv.ParseUint(tok.value, 0, 32); err == nil {
@@ -661,6 +669,10 @@
// UnmarshalText reads a protocol buffer in Text format. UnmarshalText resets pb
// before starting to unmarshal, so any existing data in pb is always removed.
func UnmarshalText(s string, pb Message) error {
+ if um, ok := pb.(textUnmarshaler); ok {
+ err := um.UnmarshalText([]byte(s))
+ return err
+ }
pb.Reset()
v := reflect.ValueOf(pb)
if pe := newTextParser(s).readStruct(v.Elem(), ""); pe != nil {
diff --git a/proto/text_parser_test.go b/proto/text_parser_test.go
index 5949065..e447ffa 100644
--- a/proto/text_parser_test.go
+++ b/proto/text_parser_test.go
@@ -413,6 +413,16 @@
}
}
+func TestUnmarshalTextCustomMessage(t *testing.T) {
+ msg := &textMessage{}
+ if err := UnmarshalText("custom", msg); err != nil {
+ t.Errorf("Unexpected error from custom unmarshal: %v", err)
+ }
+ if UnmarshalText("not custom", msg) == nil {
+ t.Errorf("Didn't get expected error from custom unmarshal")
+ }
+}
+
// Regression test; this caused a panic.
func TestRepeatedEnum(t *testing.T) {
pb := new(RepeatedEnum)
diff --git a/proto/text_test.go b/proto/text_test.go
index c64b073..4b76720 100644
--- a/proto/text_test.go
+++ b/proto/text_test.go
@@ -44,6 +44,26 @@
pb "./testdata"
)
+// textMessage implements the methods that allow it to marshal and unmarshal
+// itself as text.
+type textMessage struct {
+}
+
+func (*textMessage) MarshalText() ([]byte, error) {
+ return []byte("custom"), nil
+}
+
+func (*textMessage) UnmarshalText(bytes []byte) error {
+ if string(bytes) != "custom" {
+ return errors.New("expected 'custom'")
+ }
+ return nil
+}
+
+func (*textMessage) Reset() {}
+func (*textMessage) String() string { return "" }
+func (*textMessage) ProtoMessage() {}
+
func newTestMessage() *pb.MyMessage {
msg := &pb.MyMessage{
Count: proto.Int32(42),
@@ -153,6 +173,16 @@
}
}
+func TestMarshalTextCustomMessage(t *testing.T) {
+ buf := new(bytes.Buffer)
+ if err := proto.MarshalText(buf, &textMessage{}); err != nil {
+ t.Fatalf("proto.MarshalText: %v", err)
+ }
+ s := buf.String()
+ if s != "custom" {
+ t.Errorf("Got %q, expected %q", s, "custom")
+ }
+}
func TestMarshalTextNil(t *testing.T) {
want := "<nil>"
tests := []proto.Message{nil, (*pb.MyMessage)(nil)}