CompositeType fields contain name and oid

composite_bench_test.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/jackc/pgio"
 	"github.com/jackc/pgtype"
+	"github.com/stretchr/testify/require"
 )
 
 type MyCompositeRaw struct {
@@ -83,7 +84,11 @@ func BenchmarkBinaryEncodingComposite(b *testing.B) {
 	ci := pgtype.NewConnInfo()
 	f1 := 2
 	f2 := ptrS("bar")
-	c := pgtype.NewCompositeType("test", &pgtype.Int4{}, &pgtype.Text{})
+	c, err := pgtype.NewCompositeType("test", []pgtype.CompositeTypeField{
+		{"a", pgtype.Int4OID},
+		{"b", pgtype.TextOID},
+	}, ci)
+	require.NoError(b, err)
 
 	b.ResetTimer()
 	for n := 0; n < b.N; n++ {
@@ -146,7 +151,11 @@ func BenchmarkBinaryDecodingCompositeScan(b *testing.B) {
 	var f1 int
 	var f2 *string
 
-	c := pgtype.NewCompositeType("test", &pgtype.Int4{}, &pgtype.Text{})
+	c, err := pgtype.NewCompositeType("test", []pgtype.CompositeTypeField{
+		{"a", pgtype.Int4OID},
+		{"b", pgtype.TextOID},
+	}, ci)
+	require.NoError(b, err)
 
 	b.ResetTimer()
 	for n := 0; n < b.N; n++ {

composite_type.go

@@ -9,30 +9,59 @@ import (
 	errors "golang.org/x/xerrors"
 )
 
+type CompositeTypeField struct {
+	Name string
+	OID  uint32
+}
+
 type CompositeType struct {
 	status Status
 
 	typeName string
-	fields   []ValueTranscoder
+
+	fields           []CompositeTypeField
+	valueTranscoders []ValueTranscoder
 }
 
-// NewCompositeType creates a Composite object, which acts as a "schema" for
+// NewCompositeType creates a CompositeType from fields and ci. ci is used to find the ValueTranscoders used
-// SQL composite values.
+// for fields. All field OIDs must be previously registered in ci.
-// To pass Composite as SQL parameter first set it's fields, either by
+func NewCompositeType(typeName string, fields []CompositeTypeField, ci *ConnInfo) (*CompositeType, error) {
-// passing initialized Value{} instances to NewCompositeType or by calling
+	valueTranscoders := make([]ValueTranscoder, len(fields))
-// SetFields method
+
-// To read composite fields back pass result of Scan() method
+	for i := range fields {
-// to query Scan function.
+		dt, ok := ci.DataTypeForOID(fields[i].OID)
-func NewCompositeType(typeName string, fields ...ValueTranscoder) *CompositeType {
+		if !ok {
-	return &CompositeType{typeName: typeName, fields: fields}
+			return nil, errors.Errorf("no data type registered for oid: %d", fields[i].OID)
+		}
+
+		value := NewValue(dt.Value)
+		valueTranscoder, ok := value.(ValueTranscoder)
+		if !ok {
+			return nil, errors.Errorf("data type for oid does not implement ValueTranscoder: %d", fields[i].OID)
+		}
+
+		valueTranscoders[i] = valueTranscoder
+	}
+
+	return &CompositeType{typeName: typeName, fields: fields, valueTranscoders: valueTranscoders}, nil
+}
+
+// NewCompositeTypeValues creates a CompositeType from fields and values. fields and values must have the same length.
+// Prefer NewCompositeType unless overriding the transcoding of fields is required.
+func NewCompositeTypeValues(typeName string, fields []CompositeTypeField, values []ValueTranscoder) (*CompositeType, error) {
+	if len(fields) != len(values) {
+		return nil, errors.New("fields and valueTranscoders must have same length")
+	}
+
+	return &CompositeType{typeName: typeName, fields: fields, valueTranscoders: values}, nil
 }
 
 func (src CompositeType) Get() interface{} {
 	switch src.status {
 	case Present:
-		results := make([]interface{}, len(src.fields))
+		results := make([]interface{}, len(src.valueTranscoders))
 		for i := range results {
-			results[i] = src.fields[i].Get()
+			results[i] = src.valueTranscoders[i].Get()
 		}
 		return results
 	case Null:
@@ -44,12 +73,13 @@ func (src CompositeType) Get() interface{} {
 
 func (ct *CompositeType) NewTypeValue() Value {
 	a := &CompositeType{
-		typeName: ct.typeName,
+		typeName:         ct.typeName,
-		fields:   make([]ValueTranscoder, len(ct.fields)),
+		fields:           ct.fields,
+		valueTranscoders: make([]ValueTranscoder, len(ct.valueTranscoders)),
 	}
 
-	for i := range ct.fields {
+	for i := range ct.valueTranscoders {
-		a.fields[i] = NewValue(ct.fields[i]).(ValueTranscoder)
+		a.valueTranscoders[i] = NewValue(ct.valueTranscoders[i]).(ValueTranscoder)
 	}
 
 	return a
@@ -59,6 +89,10 @@ func (ct *CompositeType) TypeName() string {
 	return ct.typeName
 }
 
+func (ct *CompositeType) Fields() []CompositeTypeField {
+	return ct.fields
+}
+
 func (dst *CompositeType) Set(src interface{}) error {
 	if src == nil {
 		dst.status = Null
@@ -67,11 +101,11 @@ func (dst *CompositeType) Set(src interface{}) error {
 
 	switch value := src.(type) {
 	case []interface{}:
-		if len(value) != len(dst.fields) {
+		if len(value) != len(dst.valueTranscoders) {
-			return errors.Errorf("Number of fields don't match. CompositeType has %d fields", len(dst.fields))
+			return errors.Errorf("Number of fields don't match. CompositeType has %d fields", len(dst.valueTranscoders))
 		}
 		for i, v := range value {
-			if err := dst.fields[i].Set(v); err != nil {
+			if err := dst.valueTranscoders[i].Set(v); err != nil {
 				return err
 			}
 		}
@@ -95,15 +129,15 @@ func (src CompositeType) AssignTo(dst interface{}) error {
 	case Present:
 		switch v := dst.(type) {
 		case []interface{}:
-			if len(v) != len(src.fields) {
+			if len(v) != len(src.valueTranscoders) {
-				return errors.Errorf("Number of fields don't match. CompositeType has %d fields", len(src.fields))
+				return errors.Errorf("Number of fields don't match. CompositeType has %d fields", len(src.valueTranscoders))
 			}
-			for i := range src.fields {
+			for i := range src.valueTranscoders {
 				if v[i] == nil {
 					continue
 				}
 
-				err := assignToOrSet(src.fields[i], v[i])
+				err := assignToOrSet(src.valueTranscoders[i], v[i])
 				if err != nil {
 					return errors.Errorf("unable to assign to dst[%d]: %v", i, err)
 				}
@@ -169,12 +203,12 @@ func (src CompositeType) assignToPtrStruct(dst interface{}) (bool, error) {
 		}
 	}
 
-	if len(exportedFields) != len(src.fields) {
+	if len(exportedFields) != len(src.valueTranscoders) {
 		return false, nil
 	}
 
 	for i := range exportedFields {
-		err := assignToOrSet(src.fields[i], dstElemValue.Field(exportedFields[i]).Addr().Interface())
+		err := assignToOrSet(src.valueTranscoders[i], dstElemValue.Field(exportedFields[i]).Addr().Interface())
 		if err != nil {
 			return true, errors.Errorf("unable to assign to field %s: %v", dstElemType.Field(exportedFields[i]).Name, err)
 		}
@@ -192,13 +226,8 @@ func (src CompositeType) EncodeBinary(ci *ConnInfo, buf []byte) (newBuf []byte,
 	}
 
 	b := NewCompositeBinaryBuilder(ci, buf)
-	for _, f := range src.fields {
+	for i := range src.valueTranscoders {
-		dt, ok := ci.DataTypeForValue(f)
+		b.AppendEncoder(src.fields[i].OID, src.valueTranscoders[i])
-		if !ok {
-			return nil, errors.Errorf("unknown oid")
-		}
-
-		b.AppendEncoder(dt.OID, f)
 	}
 
 	return b.Finish()
@@ -216,7 +245,7 @@ func (dst *CompositeType) DecodeBinary(ci *ConnInfo, buf []byte) error {
 
 	scanner := NewCompositeBinaryScanner(ci, buf)
 
-	for _, f := range dst.fields {
+	for _, f := range dst.valueTranscoders {
 		scanner.ScanDecoder(f)
 	}
 
@@ -237,7 +266,7 @@ func (dst *CompositeType) DecodeText(ci *ConnInfo, buf []byte) error {
 
 	scanner := NewCompositeTextScanner(ci, buf)
 
-	for _, f := range dst.fields {
+	for _, f := range dst.valueTranscoders {
 		scanner.ScanDecoder(f)
 	}
 
@@ -259,7 +288,7 @@ func (src CompositeType) EncodeText(ci *ConnInfo, buf []byte) (newBuf []byte, er
 	}
 
 	b := NewCompositeTextBuilder(ci, buf)
-	for _, f := range src.fields {
+	for _, f := range src.valueTranscoders {
 		b.AppendEncoder(f)
 	}
 

composite_type_test.go

@@ -14,7 +14,12 @@ import (
 )
 
 func TestCompositeTypeSetAndGet(t *testing.T) {
-	ct := pgtype.NewCompositeType("test", &pgtype.Text{}, &pgtype.Int4{})
+	ci := pgtype.NewConnInfo()
+	ct, err := pgtype.NewCompositeType("test", []pgtype.CompositeTypeField{
+		{"a", pgtype.TextOID},
+		{"b", pgtype.Int4OID},
+	}, ci)
+	require.NoError(t, err)
 	assert.Equal(t, pgtype.Undefined, ct.Get())
 
 	nilTests := []struct {
@@ -56,7 +61,12 @@ func TestCompositeTypeSetAndGet(t *testing.T) {
 }
 
 func TestCompositeTypeAssignTo(t *testing.T) {
-	ct := pgtype.NewCompositeType("test", &pgtype.Text{}, &pgtype.Int4{})
+	ci := pgtype.NewConnInfo()
+	ct, err := pgtype.NewCompositeType("test", []pgtype.CompositeTypeField{
+		{"a", pgtype.TextOID},
+		{"b", pgtype.Int4OID},
+	}, ci)
+	require.NoError(t, err)
 
 	{
 		err := ct.Set([]interface{}{"foo", int32(42)})
@@ -168,8 +178,12 @@ create type ct_test as (
 
 	defer conn.Exec(context.Background(), "drop type ct_test")
 
-	ct := pgtype.NewCompositeType("ct_test", &pgtype.Text{}, &pgtype.Int4{})
+	ct, err := pgtype.NewCompositeType("ct_test", []pgtype.CompositeTypeField{
-	conn.ConnInfo().RegisterDataType(pgtype.DataType{Value: ct, Name: "ct_test", OID: oid})
+		{"a", pgtype.TextOID},
+		{"b", pgtype.Int4OID},
+	}, conn.ConnInfo())
+	require.NoError(t, err)
+	conn.ConnInfo().RegisterDataType(pgtype.DataType{Value: ct, Name: ct.TypeName(), OID: oid})
 
 	// Use simple protocol to force text or binary encoding
 	simpleProtocols := []bool{true, false}
@@ -221,8 +235,15 @@ func Example_composite() {
 		return
 	}
 
-	c := pgtype.NewCompositeType("mytype", &pgtype.Int4{}, &pgtype.Text{})
+	ct, err := pgtype.NewCompositeType("mytype", []pgtype.CompositeTypeField{
-	conn.ConnInfo().RegisterDataType(pgtype.DataType{Value: c, Name: "mytype", OID: oid})
+		{"a", pgtype.Int4OID},
+		{"b", pgtype.TextOID},
+	}, conn.ConnInfo())
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	conn.ConnInfo().RegisterDataType(pgtype.DataType{Value: ct, Name: ct.TypeName(), OID: oid})
 
 	var a int
 	var b *string