Fix ReceiveMessage to work without any subscriptions.

internal/proto/reader.go

@@ -26,13 +26,17 @@ type Reader struct {
 	buf []byte
 }
 
-func NewReader(rd io.Reader) *Reader {
+func NewReader(rd io.Reader, buf []byte) *Reader {
 	return &Reader{
 		src: bufio.NewReader(rd),
-		buf: make([]byte, 0, bufferSize),
+		buf: buf,
 	}
 }
 
+func (r *Reader) Reset(rd io.Reader) {
+	r.src.Reset(rd)
+}
+
 func (p *Reader) PeekBuffered() []byte {
 	if n := p.src.Buffered(); n != 0 {
 		b, _ := p.src.Peek(n)
@@ -42,7 +46,12 @@ func (p *Reader) PeekBuffered() []byte {
 }
 
 func (p *Reader) ReadN(n int) ([]byte, error) {
-	return readN(p.src, p.buf, n)
+	b, err := readN(p.src, p.buf, n)
+	if err != nil {
+		return nil, err
+	}
+	p.buf = b
+	return b, nil
 }
 
 func (p *Reader) ReadLine() ([]byte, error) {
@@ -72,11 +81,11 @@ func (p *Reader) ReadReply(m MultiBulkParse) (interface{}, error) {
 	case ErrorReply:
 		return nil, ParseErrorReply(line)
 	case StatusReply:
-		return parseStatusValue(line)
+		return parseStatusValue(line), nil
 	case IntReply:
 		return parseInt(line[1:], 10, 64)
 	case StringReply:
-		return p.readBytesValue(line)
+		return p.readTmpBytesValue(line)
 	case ArrayReply:
 		n, err := parseArrayLen(line)
 		if err != nil {
@@ -111,9 +120,9 @@ func (p *Reader) ReadTmpBytesReply() ([]byte, error) {
 	case ErrorReply:
 		return nil, ParseErrorReply(line)
 	case StringReply:
-		return p.readBytesValue(line)
+		return p.readTmpBytesValue(line)
 	case StatusReply:
-		return parseStatusValue(line)
+		return parseStatusValue(line), nil
 	default:
 		return nil, fmt.Errorf("redis: can't parse string reply: %.100q", line)
 	}
@@ -210,7 +219,7 @@ func (p *Reader) ReadScanReply() ([]string, uint64, error) {
 	return keys, cursor, err
 }
 
-func (p *Reader) readBytesValue(line []byte) ([]byte, error) {
+func (p *Reader) readTmpBytesValue(line []byte) ([]byte, error) {
 	if isNilReply(line) {
 		return nil, internal.Nil
 	}
@@ -297,8 +306,8 @@ func ParseErrorReply(line []byte) error {
 	return internal.RedisError(string(line[1:]))
 }
 
-func parseStatusValue(line []byte) ([]byte, error) {
-	return line[1:], nil
+func parseStatusValue(line []byte) []byte {
+	return line[1:]
 }
 
 func parseArrayLen(line []byte) (int64, error) {

internal/proto/reader_test.go

@@ -5,27 +5,27 @@ import (
 	"strings"
 	"testing"
 
+	"gopkg.in/redis.v5/internal/proto"
+
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
-	"gopkg.in/redis.v5/internal/proto"
 )
 
 var _ = Describe("Reader", func() {
 
 	It("should read n bytes", func() {
-		data, err := proto.NewReader(strings.NewReader("ABCDEFGHIJKLMNO")).ReadN(10)
+		data, err := proto.NewReader(strings.NewReader("ABCDEFGHIJKLMNO"), nil).ReadN(10)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(len(data)).To(Equal(10))
 		Expect(string(data)).To(Equal("ABCDEFGHIJ"))
 
-		data, err = proto.NewReader(strings.NewReader(strings.Repeat("x", 8192))).ReadN(6000)
+		data, err = proto.NewReader(strings.NewReader(strings.Repeat("x", 8192)), nil).ReadN(6000)
 		Expect(err).NotTo(HaveOccurred())
 		Expect(len(data)).To(Equal(6000))
 	})
 
 	It("should read lines", func() {
-		p := proto.NewReader(strings.NewReader("$5\r\nhello\r\n"))
+		p := proto.NewReader(strings.NewReader("$5\r\nhello\r\n"), nil)
 
 		data, err := p.ReadLine()
 		Expect(err).NotTo(HaveOccurred())
@@ -59,11 +59,11 @@ func BenchmarkReader_ParseReply_Slice(b *testing.B) {
 }
 
 func benchmarkParseReply(b *testing.B, reply string, m proto.MultiBulkParse, wanterr bool) {
-	buf := &bytes.Buffer{}
+	buf := new(bytes.Buffer)
 	for i := 0; i < b.N; i++ {
 		buf.WriteString(reply)
 	}
-	p := proto.NewReader(buf)
+	p := proto.NewReader(buf, nil)
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {

internal/proto/write_buffer.go

@@ -8,11 +8,13 @@ import (
 
 const bufferSize = 4096
 
-type WriteBuffer struct{ b []byte }
+type WriteBuffer struct {
+	b []byte
+}
 
-func NewWriteBuffer() *WriteBuffer {
+func NewWriteBuffer(b []byte) *WriteBuffer {
 	return &WriteBuffer{
-		b: make([]byte, 0, bufferSize),
+		b: b,
 	}
 }
 

internal/proto/write_buffer_test.go

@@ -4,17 +4,17 @@ import (
 	"testing"
 	"time"
 
+	"gopkg.in/redis.v5/internal/proto"
+
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
-
-	"gopkg.in/redis.v5/internal/proto"
 )
 
 var _ = Describe("WriteBuffer", func() {
 	var buf *proto.WriteBuffer
 
 	BeforeEach(func() {
-		buf = proto.NewWriteBuffer()
+		buf = proto.NewWriteBuffer(nil)
 	})
 
 	It("should reset", func() {
@@ -53,7 +53,7 @@ var _ = Describe("WriteBuffer", func() {
 })
 
 func BenchmarkWriteBuffer_Append(b *testing.B) {
-	buf := proto.NewWriteBuffer()
+	buf := proto.NewWriteBuffer(nil)
 	args := []interface{}{"hello", "world", "foo", "bar"}
 
 	for i := 0; i < b.N; i++ {