Merge pull request #2930 from fjl/ethclient

Stable Go API, part 1

2 files changed, 52 insertions, 0 deletions

diff --git a/rpc/types.go b/rpc/types.go
index 89c5b5bc9..ebe388373 100644
--- a/rpc/types.go
+++ b/rpc/types.go
@@ -17,6 +17,8 @@
 package rpc
 
 import (
+	"bytes"
+	"encoding/hex"
 	"fmt"
 	"math"
 	"math/big"
@@ -272,3 +274,31 @@ func (bn *BlockNumber) UnmarshalJSON(data []byte) error {
 func (bn BlockNumber) Int64() int64 {
 	return (int64)(bn)
 }
+
+// HexBytes JSON-encodes as hex with 0x prefix.
+type HexBytes []byte
+
+func (b HexBytes) MarshalJSON() ([]byte, error) {
+	result := make([]byte, len(b)*2+4)
+	copy(result, `"0x`)
+	hex.Encode(result[3:], b)
+	result[len(result)-1] = '"'
+	return result, nil
+}
+
+func (b *HexBytes) UnmarshalJSON(input []byte) error {
+	if len(input) >= 2 && input[0] == '"' && input[len(input)-1] == '"' {
+		input = input[1 : len(input)-1]
+	}
+	if !bytes.HasPrefix(input, []byte("0x")) {
+		return fmt.Errorf("missing 0x prefix for hex byte array")
+	}
+	input = input[2:]
+	if len(input) == 0 {
+		*b = nil
+		return nil
+	}
+	*b = make([]byte, len(input)/2)
+	_, err := hex.Decode(*b, input)
+	return err
+}
diff --git a/rpc/types_test.go b/rpc/types_test.go
index c2c5c6db6..5482557b8 100644
--- a/rpc/types_test.go
+++ b/rpc/types_test.go
@@ -71,3 +71,25 @@ func TestHexNumberMarshalJSON(t *testing.T) {
 		t.Fatalf("Invalid json.Marshal, expected '%s', got '%s'", exp, got)
 	}
 }
+
+var hexBytesTests = []struct{ in, out []byte }{
+	{in: []byte(`"0x"`), out: []byte{}},
+	{in: []byte(`"0x00"`), out: []byte{0}},
+	{in: []byte(`"0x01ff"`), out: []byte{0x01, 0xFF}},
+}
+
+func TestHexBytes(t *testing.T) {
+	for i, test := range hexBytesTests {
+		var dec HexBytes
+		if err := json.Unmarshal(test.in, &dec); err != nil {
+			t.Fatalf("test %d: can't decode: %v", i, err)
+		}
+		enc, _ := json.Marshal(HexBytes(test.out))
+		if !bytes.Equal(dec, test.out) {
+			t.Errorf("test %d: wrong decoded value 0x%x", i, dec)
+		}
+		if !bytes.Equal(enc, test.in) {
+			t.Errorf("test %d: wrong encoded value %#q", i, enc)
+		}
+	}
+}