applied small refactor writeResultSet to minimize code duplication

server/resp.go

@@ -125,15 +125,7 @@ func (c *Conn) writeResultset(r *Resultset) error {
 		return err
 	}
 
-	for _, v := range r.Fields {
-		data = data[0:4]
-		data = append(data, v.Dump()...)
-		if err := c.WritePacket(data); err != nil {
-			return err
-		}
-	}
-
-	if err := c.writeEOF(); err != nil {
+	if err := c.writeFieldList(r.Fields, data); err != nil {
 		return err
 	}
 
@@ -152,8 +144,10 @@ func (c *Conn) writeResultset(r *Resultset) error {
 	return nil
 }
 
-func (c *Conn) writeFieldList(fs []*Field) error {
-	data := make([]byte, 4, 1024)
+func (c *Conn) writeFieldList(fs []*Field, data []byte) error {
+	if data == nil {
+		data = make([]byte, 4, 1024)
+	}
 
 	for _, v := range fs {
 		data = data[0:4]
@@ -189,7 +183,7 @@ func (c *Conn) writeValue(value interface{}) error {
 			return c.writeOK(v)
 		}
 	case []*Field:
-		return c.writeFieldList(v)
+		return c.writeFieldList(v, nil)
 	case *Stmt:
 		return c.writePrepare(v)
 	default:

server/resp_test.go

@@ -0,0 +1,191 @@
+package server
+
+import (
+	"errors"
+
+	"github.com/go-mysql-org/go-mysql/mysql"
+	"github.com/go-mysql-org/go-mysql/packet"
+	mockconn "github.com/go-mysql-org/go-mysql/test_util/conn"
+	"github.com/pingcap/check"
+)
+
+type respConnTestSuite struct{}
+
+var _ = check.Suite(&respConnTestSuite{})
+
+func (t *respConnTestSuite) TestConnWriteOK(c *check.C) {
+	clientConn := &mockconn.MockConn{}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	result := &mysql.Result{
+		AffectedRows: 1,
+		InsertId:     2,
+	}
+
+	// write ok with insertid and affectedrows set
+	err := conn.writeOK(result)
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{3, 0, 0, 0, mysql.OK_HEADER, 1, 2})
+
+	// set capability for CLIENT_PROTOCOL_41
+	conn.SetCapability(mysql.CLIENT_PROTOCOL_41)
+	conn.SetStatus(mysql.SERVER_QUERY_WAS_SLOW)
+	err = conn.writeOK(result)
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{7, 0, 0, 1, mysql.OK_HEADER, 1, 2, 0, 8, 0, 0})
+}
+
+func (t *respConnTestSuite) TestConnWriteEOF(c *check.C) {
+	clientConn := &mockconn.MockConn{}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	// write regular EOF
+	err := conn.writeEOF()
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{1, 0, 0, 0, mysql.EOF_HEADER})
+
+	// set capability for CLIENT_PROTOCOL_41
+	conn.SetCapability(mysql.CLIENT_PROTOCOL_41)
+	conn.SetStatus(mysql.SERVER_MORE_RESULTS_EXISTS)
+	err = conn.writeEOF()
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{5, 0, 0, 1, mysql.EOF_HEADER,
+		0, 0, 8, 0})
+}
+
+func (t *respConnTestSuite) TestConnWriteError(c *check.C) {
+	clientConn := &mockconn.MockConn{}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+	merr := mysql.NewDefaultError(mysql.ER_YES) // nice and short error message
+
+	// write regular Error
+	err := conn.writeError(merr)
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{6, 0, 0, 0, mysql.ERR_HEADER,
+		235, 3, 89, 69, 83})
+
+	// set capability for CLIENT_PROTOCOL_41
+	conn.SetCapability(mysql.CLIENT_PROTOCOL_41)
+	err = conn.writeError(merr)
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{12, 0, 0, 1, mysql.ERR_HEADER,
+		235, 3, 35, 72, 89, 48, 48, 48, 89, 69, 83})
+
+	// unknown error
+	err = conn.writeError(errors.New("test"))
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{13, 0, 0, 2, mysql.ERR_HEADER,
+		81, 4, 35, 72, 89, 48, 48, 48, 116, 101, 115, 116})
+}
+
+func (t *respConnTestSuite) TestConnWriteAuthSwitchRequest(c *check.C) {
+	clientConn := &mockconn.MockConn{}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	err := conn.writeAuthSwitchRequest("test")
+	c.Assert(err, check.IsNil)
+	// first 10 bytes are static, then there is a part random, ending with a \0
+	c.Assert(clientConn.WriteBuffered[:10], check.BytesEquals, []byte{27, 0, 0, 0, mysql.EOF_HEADER,
+		116, 101, 115, 116, 0})
+	c.Assert(clientConn.WriteBuffered[len(clientConn.WriteBuffered)-1:], check.BytesEquals, []byte{0})
+}
+
+func (t *respConnTestSuite) TestConnReadAuthSwitchRequestResponse(c *check.C) {
+	clientConn := &mockconn.MockConn{}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	// prepare response for \NUL
+	clientConn.SetResponse([][]byte{{1, 0, 0, 0, 0}})
+	data, err := conn.readAuthSwitchRequestResponse()
+	c.Assert(err, check.IsNil)
+	c.Assert(data, check.BytesEquals, []byte{})
+
+	// prepare response for some auth switch data
+	clientConn.SetResponse([][]byte{{4, 0, 0, 0, 1, 2, 3, 4}})
+	conn = &Conn{Conn: packet.NewConn(clientConn)}
+
+	data, err = conn.readAuthSwitchRequestResponse()
+	c.Assert(err, check.IsNil)
+	c.Assert(data, check.BytesEquals, []byte{1, 2, 3, 4})
+}
+
+func (t *respConnTestSuite) TestConnWriteAuthMoreDataPubkey(c *check.C) {
+	clientConn := &mockconn.MockConn{}
+	conn := &Conn{
+		Conn: packet.NewConn(clientConn),
+		serverConf: &Server{
+			pubKey: []byte{1, 2, 3, 4},
+		},
+	}
+
+	err := conn.writeAuthMoreDataPubkey()
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{5, 0, 0, 0, mysql.MORE_DATE_HEADER,
+		1, 2, 3, 4})
+}
+
+func (t *respConnTestSuite) TestConnWriteAuthMoreDataFullAuth(c *check.C) {
+	clientConn := &mockconn.MockConn{}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	err := conn.writeAuthMoreDataFullAuth()
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{2, 0, 0, 0, mysql.MORE_DATE_HEADER,
+		mysql.CACHE_SHA2_FULL_AUTH})
+}
+
+func (t *respConnTestSuite) TestConnWriteAuthMoreDataFastAuth(c *check.C) {
+	clientConn := &mockconn.MockConn{}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	err := conn.writeAuthMoreDataFastAuth()
+	c.Assert(err, check.IsNil)
+	c.Assert(clientConn.WriteBuffered, check.BytesEquals, []byte{2, 0, 0, 0, mysql.MORE_DATE_HEADER,
+		mysql.CACHE_SHA2_FAST_AUTH})
+}
+
+func (t *respConnTestSuite) TestConnWriteResultset(c *check.C) {
+	clientConn := &mockconn.MockConn{MultiWrite: true}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	r := mysql.NewResultset(0)
+
+	// write minimalistic resultset
+	err := conn.writeResultset(r)
+	c.Assert(err, check.IsNil)
+	// column length 0
+	c.Assert(clientConn.WriteBuffered[:5], check.BytesEquals, []byte{1, 0, 0, 0, 0})
+	// no fields and an EOF
+	c.Assert(clientConn.WriteBuffered[5:10], check.BytesEquals, []byte{1, 0, 0, 1, mysql.EOF_HEADER})
+	// no rows and another EOF
+	c.Assert(clientConn.WriteBuffered[10:], check.BytesEquals, []byte{1, 0, 0, 2, mysql.EOF_HEADER})
+
+	// reset write buffer and fill up the resultset with (little) data
+	clientConn.WriteBuffered = []byte{}
+	r, err = mysql.BuildSimpleTextResultset([]string{"a"}, [][]interface{}{{"b"}})
+	c.Assert(err, check.IsNil)
+	err = conn.writeResultset(r)
+	c.Assert(err, check.IsNil)
+	// column length 1
+	c.Assert(clientConn.WriteBuffered[:5], check.BytesEquals, []byte{1, 0, 0, 3, 1})
+	// fields and EOF
+	c.Assert(clientConn.WriteBuffered[5:32], check.BytesEquals, []byte{23, 0, 0, 4, 3, 100, 101, 102, 0, 0, 0, 1, 'a', 0, 12, 33, 0, 0, 0, 0, 0, 253, 0, 0, 0, 0, 0})
+	c.Assert(clientConn.WriteBuffered[32:37], check.BytesEquals, []byte{1, 0, 0, 5, mysql.EOF_HEADER})
+	// rowdata and EOF
+	c.Assert(clientConn.WriteBuffered[37:43], check.BytesEquals, []byte{2, 0, 0, 6, 1, 'b'})
+	c.Assert(clientConn.WriteBuffered[43:], check.BytesEquals, []byte{1, 0, 0, 7, mysql.EOF_HEADER})
+}
+
+func (t *respConnTestSuite) TestConnWriteFieldList(c *check.C) {
+	clientConn := &mockconn.MockConn{MultiWrite: true}
+	conn := &Conn{Conn: packet.NewConn(clientConn)}
+
+	r, err := mysql.BuildSimpleTextResultset([]string{"c"}, [][]interface{}{{"d"}})
+	c.Assert(err, check.IsNil)
+	err = conn.writeFieldList(r.Fields, nil)
+	c.Assert(err, check.IsNil)
+
+	// column length 1
+	c.Assert(clientConn.WriteBuffered[:27], check.BytesEquals, []byte{23, 0, 0, 0, 3, 100, 101, 102, 0, 0, 0, 1, 'c', 0, 12, 33, 0, 0, 0, 0, 0, 253, 0, 0, 0, 0, 0})
+	c.Assert(clientConn.WriteBuffered[27:], check.BytesEquals, []byte{1, 0, 0, 1, mysql.EOF_HEADER})
+}

test_util/conn/mockconn.go

@@ -0,0 +1,77 @@
+package conn
+
+import (
+	"errors"
+	"net"
+	"time"
+)
+
+type mockAddr struct{}
+
+func (m mockAddr) String() string  { return "mocking" }
+func (m mockAddr) Network() string { return "mocking" }
+
+// MockConn is a simple struct implementing net.Conn that allows us to read what
+// was written to it and feed data it will read from
+type MockConn struct {
+	readResponses [][]byte
+	WriteBuffered []byte
+	Closed        bool
+
+	MultiWrite bool
+}
+
+func (m *MockConn) SetResponse(r [][]byte) {
+	m.readResponses = r
+}
+
+func (m *MockConn) Read(p []byte) (n int, err error) {
+	if m.Closed {
+		return -1, errors.New("connection closed")
+	}
+
+	if len(m.readResponses) == 0 {
+		return -1, errors.New("no response left")
+	}
+
+	copy(p, m.readResponses[0])
+	m.readResponses = m.readResponses[1:]
+
+	return len(p), nil
+}
+
+func (m *MockConn) Write(p []byte) (n int, err error) {
+	if m.Closed {
+		return -1, errors.New("connection closed")
+	}
+
+	if m.MultiWrite {
+		m.WriteBuffered = append(m.WriteBuffered, p...)
+	} else {
+		m.WriteBuffered = make([]byte, len(p))
+		copy(m.WriteBuffered, p)
+	}
+
+	return len(p), nil
+}
+
+func (m MockConn) LocalAddr() net.Addr  { return mockAddr{} }
+func (m MockConn) RemoteAddr() net.Addr { return mockAddr{} }
+
+func (m *MockConn) Close() error {
+	m.Closed = true
+
+	return nil
+}
+
+func (m MockConn) SetDeadline(t time.Time) error {
+	return errors.New("not implemented")
+}
+
+func (m MockConn) SetReadDeadline(t time.Time) error {
+	return errors.New("not implemented")
+}
+
+func (m MockConn) SetWriteDeadline(t time.Time) error {
+	return errors.New("not implemented")
+}