whisper: use hexutil.UnmarshalFixedText for topic parsing

cmd/geth/consolecmd.go

@@ -35,7 +35,7 @@ var (
 		Action:   utils.MigrateFlags(localConsole),
 		Name:     "console",
 		Usage:    "Start an interactive JavaScript environment",
-		Flags:    append(append(nodeFlags, rpcFlags...), consoleFlags...),
+		Flags:    append(append(append(nodeFlags, rpcFlags...), consoleFlags...), whisperFlags...),
 		Category: "CONSOLE COMMANDS",
 		Description: `
 The Geth console is an interactive shell for the JavaScript runtime environment

whisper/whisperv5/topic.go

@@ -19,9 +19,6 @@
 package whisperv5
 
 import (
-	"encoding/json"
-	"fmt"
-
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 )
@@ -47,19 +44,12 @@ func (topic *TopicType) String() string {
 	return string(common.ToHex(topic[:]))
 }
 
-func (t *TopicType) MarshalJSON() ([]byte, error) {
-	return json.Marshal(hexutil.Bytes(t[:]))
+// MarshalText returns the hex representation of t.
+func (t TopicType) MarshalText() ([]byte, error) {
+	return hexutil.Bytes(t[:]).MarshalText()
 }
 
-// UnmarshalJSON parses a hex representation to a topic.
-func (t *TopicType) UnmarshalJSON(input []byte) error {
-	var data hexutil.Bytes
-	if err := json.Unmarshal(input, &data); err != nil {
-		return err
-	}
-	if len(data) != TopicLength {
-		return fmt.Errorf("unmarshalJSON failed: topic must be exactly %d bytes(%d)", TopicLength, len(input))
-	}
-	*t = BytesToTopic(data)
-	return nil
+// UnmarshalText parses a hex representation to a topic.
+func (t *TopicType) UnmarshalText(input []byte) error {
+	return hexutil.UnmarshalFixedText("Topic", input, t[:])
 }

whisper/whisperv5/topic_test.go

@@ -16,7 +16,10 @@
 
 package whisperv5
 
-import "testing"
+import (
+	"encoding/json"
+	"testing"
+)
 
 var topicStringTests = []struct {
 	topic TopicType
@@ -53,15 +56,6 @@ var bytesToTopicTests = []struct {
 	{topic: TopicType{0x00, 0x00, 0x00, 0x00}, data: nil},
 }
 
-func TestBytesToTopic(t *testing.T) {
-	for i, tst := range bytesToTopicTests {
-		top := BytesToTopic(tst.data)
-		if top != tst.topic {
-			t.Fatalf("failed test %d: have %v, want %v.", i, t, tst.topic)
-		}
-	}
-}
-
 var unmarshalTestsGood = []struct {
 	topic TopicType
 	data  []byte
@@ -94,14 +88,23 @@ var unmarshalTestsUgly = []struct {
 	{topic: TopicType{0x01, 0x00, 0x00, 0x00}, data: []byte(`"0x00000001"`)},
 }
 
+func TestBytesToTopic(t *testing.T) {
+	for i, tst := range bytesToTopicTests {
+		top := BytesToTopic(tst.data)
+		if top != tst.topic {
+			t.Fatalf("failed test %d: have %v, want %v.", i, t, tst.topic)
+		}
+	}
+}
+
 func TestUnmarshalTestsGood(t *testing.T) {
 	for i, tst := range unmarshalTestsGood {
 		var top TopicType
-		err := top.UnmarshalJSON(tst.data)
+		err := json.Unmarshal(tst.data, &top)
 		if err != nil {
-			t.Fatalf("failed test %d. input: %v. err: %v", i, tst.data, err)
+			t.Errorf("failed test %d. input: %v. err: %v", i, tst.data, err)
 		} else if top != tst.topic {
-			t.Fatalf("failed test %d: have %v, want %v.", i, t, tst.topic)
+			t.Errorf("failed test %d: have %v, want %v.", i, t, tst.topic)
 		}
 	}
 }
@@ -110,7 +113,7 @@ func TestUnmarshalTestsBad(t *testing.T) {
 	// in this test UnmarshalJSON() is supposed to fail
 	for i, tst := range unmarshalTestsBad {
 		var top TopicType
-		err := top.UnmarshalJSON(tst.data)
+		err := json.Unmarshal(tst.data, &top)
 		if err == nil {
 			t.Fatalf("failed test %d. input: %v.", i, tst.data)
 		}
@@ -121,11 +124,11 @@ func TestUnmarshalTestsUgly(t *testing.T) {
 	// in this test UnmarshalJSON() is NOT supposed to fail, but result should be wrong
 	for i, tst := range unmarshalTestsUgly {
 		var top TopicType
-		err := top.UnmarshalJSON(tst.data)
+		err := json.Unmarshal(tst.data, &top)
 		if err != nil {
-			t.Fatalf("failed test %d. input: %v.", i, tst.data)
+			t.Errorf("failed test %d. input: %v.", i, tst.data)
 		} else if top == tst.topic {
-			t.Fatalf("failed test %d: have %v, want %v.", i, top, tst.topic)
+			t.Errorf("failed test %d: have %v, want %v.", i, top, tst.topic)
 		}
 	}
 }