tuple: serialized form (#14392)

Signed-off-by: Vicent Marti <vmg@strn.cat>

go/sqltypes/bind_variables.go

@@ -40,18 +40,21 @@ var (
 	NullBindVariable = &querypb.BindVariable{Type: querypb.Type_NULL_TYPE}
 )
 
+func TupleToProto(v []Value) *querypb.Value {
+	return &querypb.Value{
+		Type:  querypb.Type_TUPLE,
+		Value: encodeTuple(v),
+	}
+}
+
 // ValueToProto converts Value to a *querypb.Value.
 func ValueToProto(v Value) *querypb.Value {
-	var protoValues []*querypb.Value
-	for _, value := range v.values {
-		protoValues = append(protoValues, ValueToProto(value))
-	}
-	return &querypb.Value{Type: v.typ, Value: v.val, Values: protoValues}
+	return &querypb.Value{Type: v.typ, Value: v.val}
 }
 
 // ProtoToValue converts a *querypb.Value to a Value.
 func ProtoToValue(v *querypb.Value) Value {
-	return MakeTrustedValues(v.Type, v.Value, v.Values)
+	return MakeTrusted(v.Type, v.Value)
 }
 
 // BuildBindVariables builds a map[string]*querypb.BindVariable from a map[string]any

go/sqltypes/bind_variables_test.go

@@ -22,7 +22,6 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-
 	"github.com/stretchr/testify/require"
 	"google.golang.org/protobuf/proto"
 
@@ -42,67 +41,28 @@ func TestProtoConversions(t *testing.T) {
 			protoVal: &querypb.Value{Type: Int64, Value: []byte("1")},
 		}, {
 			name: "tuple value",
-			val: Value{
-				typ: Tuple,
-				values: []Value{
-					TestValue(VarChar, "1"),
-					TestValue(Int64, "3"),
-				},
-			},
-			protoVal: &querypb.Value{
-				Type: Tuple,
-				Values: []*querypb.Value{
-					{
-						Type:  VarChar,
-						Value: []byte("1"),
-					}, {
-						Type:  Int64,
-						Value: []byte("3"),
-					},
-				},
-			},
+			val:  TestTuple(TestValue(VarChar, "1"), TestValue(Int64, "3")),
 		}, {
 			name: "tuple of tuple as a value",
-			val: Value{
-				typ: Tuple,
-				values: []Value{
-					{
-						typ: Tuple,
-						values: []Value{
-							TestValue(VarChar, "1"),
-							TestValue(Int64, "3"),
-						},
-					},
-					TestValue(Int64, "5"),
-				},
-			},
-			protoVal: &querypb.Value{
-				Type: Tuple,
-				Values: []*querypb.Value{
-					{
-						Type: Tuple,
-						Values: []*querypb.Value{
-							{
-								Type:  VarChar,
-								Value: []byte("1"),
-							}, {
-								Type:  Int64,
-								Value: []byte("3"),
-							},
-						},
-					}, {
-						Type:  Int64,
-						Value: []byte("5"),
-					},
-				},
-			},
+			val: TestTuple(
+				TestTuple(
+					TestValue(VarChar, "1"),
+					TestValue(Int64, "3"),
+				),
+				TestValue(Int64, "5"),
+			),
 		},
 	}
 
 	for _, tcase := range tcases {
 		t.Run(tcase.name, func(t *testing.T) {
 			got := ValueToProto(tcase.val)
-			require.True(t, proto.Equal(got, tcase.protoVal), "ValueToProto: %v, want %v", got, tcase.protoVal)
+			// If we have an expected protoVal, check that serialization matches.
+			// For nested tuples, we do not attempt to generate a protoVal, as it is binary data.
+			// We simply check that the roundtrip is correct.
+			if tcase.protoVal != nil {
+				require.True(t, proto.Equal(got, tcase.protoVal), "ValueToProto: %v, want %v", got, tcase.protoVal)
+			}
 			gotback := ProtoToValue(got)
 			require.EqualValues(t, tcase.val, gotback)
 		})

go/sqltypes/testing.go

@@ -143,6 +143,15 @@ func TestValue(typ querypb.Type, val string) Value {
 	return MakeTrusted(typ, []byte(val))
 }
 
+// TestTuple builds a tuple Value from a list of Values.
+// This function should only be used for testing.
+func TestTuple(vals ...Value) Value {
+	return Value{
+		typ: Tuple,
+		val: encodeTuple(vals),
+	}
+}
+
 // PrintResults prints []*Results into a string.
 // This function should only be used for testing.
 func PrintResults(results []*Result) string {

go/sqltypes/value.go

@@ -27,6 +27,8 @@ import (
 	"strconv"
 	"strings"
 
+	"google.golang.org/protobuf/encoding/protowire"
+
 	"vitess.io/vitess/go/bytes2"
 	"vitess.io/vitess/go/hack"
 	"vitess.io/vitess/go/mysql/decimal"
@@ -63,9 +65,8 @@ type (
 	// an integral type, the bytes are always stored as a canonical
 	// representation that matches how MySQL returns such values.
 	Value struct {
-		typ    querypb.Type
-		val    []byte
-		values []Value
+		typ querypb.Type
+		val []byte
 	}
 
 	Row = []Value
@@ -110,19 +111,10 @@ func NewValue(typ querypb.Type, val []byte) (v Value, err error) {
 // comments. Other packages can also use the function to create
 // VarBinary or VarChar values.
 func MakeTrusted(typ querypb.Type, val []byte) Value {
-	return MakeTrustedValues(typ, val, nil)
-}
-
-func MakeTrustedValues(typ querypb.Type, val []byte, values []*querypb.Value) Value {
 	if typ == Null {
 		return NULL
 	}
-	var sqlValues []Value
-	for _, v := range values {
-		sqlValues = append(sqlValues,
-			MakeTrustedValues(v.Type, v.Value, v.Values))
-	}
-	return Value{typ: typ, val: val, values: sqlValues}
+	return Value{typ: typ, val: val}
 }
 
 // NewHexNum builds an Hex Value.
@@ -454,12 +446,14 @@ func (v Value) EncodeSQLStringBuilder(b *strings.Builder) {
 		encodeBytesSQLBits(v.val, b)
 	case v.typ == Tuple:
 		b.WriteByte('(')
-		for i, bv := range v.values {
-			if i != 0 {
+		var i int
+		_ = v.ForEachValue(func(bv Value) {
+			if i > 0 {
 				b.WriteString(", ")
 			}
 			bv.EncodeSQLStringBuilder(b)
-		}
+			i++
+		})
 		b.WriteByte(')')
 	default:
 		b.Write(v.val)
@@ -658,6 +652,51 @@ func (v *Value) decodeBitNum() ([]byte, error) {
 	return i.Bytes(), nil
 }
 
+var ErrBadTupleEncoding = errors.New("bad tuple encoding in sqltypes.Value")
+
+func encodeTuple(tuple []Value) []byte {
+	var total int
+	for _, v := range tuple {
+		total += len(v.val) + 3
+	}
+
+	buf := make([]byte, 0, total)
+	for _, v := range tuple {
+		buf = protowire.AppendVarint(buf, uint64(v.typ))
+		buf = protowire.AppendVarint(buf, uint64(len(v.val)))
+		buf = append(buf, v.val...)
+	}
+	return buf
+}
+
+func (v *Value) ForEachValue(each func(bv Value)) error {
+	if v.typ != Tuple {
+		panic("Value.ForEachValue on non-tuple")
+	}
+
+	var sz, ty uint64
+	var varlen int
+	buf := v.val
+	for len(buf) > 0 {
+		ty, varlen = protowire.ConsumeVarint(buf)
+		if varlen < 0 {
+			return ErrBadTupleEncoding
+		}
+
+		buf = buf[varlen:]
+		sz, varlen = protowire.ConsumeVarint(buf)
+		if varlen < 0 {
+			return ErrBadTupleEncoding
+		}
+
+		buf = buf[varlen:]
+		each(Value{val: buf[:sz], typ: Type(ty)})
+
+		buf = buf[sz:]
+	}
+	return nil
+}
+
 func encodeBytesSQL(val []byte, b BinWriter) {
 	buf := &bytes2.Buffer{}
 	encodeBytesSQLBytes2(val, buf)