Move lowlevel binary routines into own package

binary/record.go

@@ -0,0 +1,78 @@
+package binary
+
+import (
+	"encoding/binary"
+
+	"github.com/jackc/pgio"
+	errors "golang.org/x/xerrors"
+)
+
+type RecordFieldIter struct {
+	rp  int
+	src []byte
+}
+
+// NewRecordFieldIterator creates iterator over binary representation
+// of record, aka ROW(), aka Composite
+func NewRecordFieldIterator(src []byte) (RecordFieldIter, int, error) {
+	rp := 0
+	if len(src[rp:]) < 4 {
+		return RecordFieldIter{}, 0, errors.Errorf("Record incomplete %v", src)
+	}
+
+	fieldCount := int(int32(binary.BigEndian.Uint32(src[rp:])))
+	rp += 4
+
+	return RecordFieldIter{
+		rp:  rp,
+		src: src,
+	}, fieldCount, nil
+}
+
+// Next returns next field decoded from record. eof is returned if no
+// more fields left to decode.
+func (fi *RecordFieldIter) Next() (fieldOID uint32, buf []byte, eof bool, err error) {
+	if fi.rp == len(fi.src) {
+		eof = true
+		return
+	}
+
+	if len(fi.src[fi.rp:]) < 8 {
+		err = errors.Errorf("Record incomplete %v", fi.src)
+		return
+	}
+	fieldOID = binary.BigEndian.Uint32(fi.src[fi.rp:])
+	fi.rp += 4
+
+	fieldLen := int(int32(binary.BigEndian.Uint32(fi.src[fi.rp:])))
+	fi.rp += 4
+
+	if fieldLen >= 0 {
+		if len(fi.src[fi.rp:]) < fieldLen {
+			err = errors.Errorf("Record incomplete rp=%d src=%v", fi.rp, fi.src)
+			return
+		}
+		buf = fi.src[fi.rp : fi.rp+fieldLen]
+		fi.rp += fieldLen
+	}
+
+	return
+}
+
+// RecordStart adds record header to the buf
+func RecordStart(buf []byte, fieldCount int) []byte {
+	return pgio.AppendUint32(buf, uint32(fieldCount))
+}
+
+// RecordAdd adds record field to the buf
+func RecordAdd(buf []byte, oid uint32, fieldBytes []byte) []byte {
+	buf = pgio.AppendUint32(buf, oid)
+	buf = pgio.AppendUint32(buf, uint32(len(fieldBytes)))
+	buf = append(buf, fieldBytes...)
+	return buf
+}
+
+// RecordAddNull adds null value as a field to the buf
+func RecordAddNull(buf []byte, oid uint32) []byte {
+	return pgio.AppendInt32(buf, int32(-1))
+}

convert.go

@@ -5,7 +5,7 @@ import (
 	"reflect"
 	"time"
 
-	"github.com/jackc/pgio"
+	"github.com/jackc/pgtype/binary"
 	errors "golang.org/x/xerrors"
 )
 
@@ -442,16 +442,16 @@ func GetAssignToDstType(dst interface{}) (interface{}, bool) {
 // Values must implement BinaryDecoder interface otherwise error is returned.
 // ScanRowValue takes ownership of src, caller MUST not use it after call
 func ScanRowValue(ci *ConnInfo, src []byte, dst ...Value) error {
-	fieldIter, err := newFieldIterator(src)
+	fieldIter, fieldCount, err := binary.NewRecordFieldIterator(src)
 	if err != nil {
 		return err
 	}
 
-	if len(dst) != fieldIter.fieldCount {
+	if len(dst) != fieldCount {
-		return errors.Errorf("can't scan row value, number of fields don't match: row fields count=%d desired fields count=%d", fieldIter.fieldCount, len(dst))
+		return errors.Errorf("can't scan row value, number of fields don't match: row fields count=%d desired fields count=%d", fieldCount, len(dst))
 	}
 
-	_, fieldBytes, eof, err := fieldIter.next()
+	_, fieldBytes, eof, err := fieldIter.Next()
 	for i := 0; !eof; i++ {
 		if err != nil {
 			return err
@@ -466,7 +466,7 @@ func ScanRowValue(ci *ConnInfo, src []byte, dst ...Value) error {
 			return err
 		}
 
-		_, fieldBytes, eof, err = fieldIter.next()
+		_, fieldBytes, eof, err = fieldIter.Next()
 	}
 
 	return nil
@@ -476,14 +476,12 @@ func ScanRowValue(ci *ConnInfo, src []byte, dst ...Value) error {
 func EncodeRow(ci *ConnInfo, buf []byte, fields ...Value) (newBuf []byte, err error) {
 	fieldBytes := make([]byte, 0, 128)
 
-	newBuf = pgio.AppendUint32(buf, uint32(len(fields)))
+	newBuf = binary.RecordStart(buf, len(fields))
 	for _, f := range fields {
 		dt, ok := ci.DataTypeForValue(f)
 		if !ok {
 			return nil, errors.Errorf("Unknown OID for %s", f)
 		}
-		newBuf = pgio.AppendUint32(newBuf, dt.OID)
-
 		if f.Get() != nil {
 			binaryEncoder, ok := f.(BinaryEncoder)
 			if !ok {
@@ -493,11 +491,9 @@ func EncodeRow(ci *ConnInfo, buf []byte, fields ...Value) (newBuf []byte, err er
 			if err != nil {
 				return nil, err
 			}
-
+			newBuf = binary.RecordAdd(newBuf, dt.OID, fieldBytes)
-			newBuf = pgio.AppendUint32(newBuf, uint32(len(fieldBytes)))
-			newBuf = append(newBuf, fieldBytes...)
 		} else {
-			newBuf = pgio.AppendInt32(newBuf, int32(-1))
+			newBuf = binary.RecordAddNull(newBuf, dt.OID)
 		}
 
 	}

record.go

@@ -1,9 +1,10 @@
 package pgtype
 
 import (
-	"encoding/binary"
 	"reflect"
 
+	"github.com/jackc/pgtype/binary"
+
 	errors "golang.org/x/xerrors"
 )
 
@@ -78,56 +79,6 @@ func (src *Record) AssignTo(dst interface{}) error {
 	return errors.Errorf("cannot decode %#v into %T", src, dst)
 }
 
-type fieldIter struct {
-	rp         int
-	fieldCount int
-	src        []byte
-}
-
-func newFieldIterator(src []byte) (fieldIter, error) {
-	rp := 0
-	if len(src[rp:]) < 4 {
-		return fieldIter{}, errors.Errorf("Record incomplete %v", src)
-	}
-
-	fieldCount := int(int32(binary.BigEndian.Uint32(src[rp:])))
-	rp += 4
-
-	return fieldIter{
-		rp:         rp,
-		fieldCount: fieldCount,
-		src:        src,
-	}, nil
-}
-
-func (fi *fieldIter) next() (fieldOID uint32, buf []byte, eof bool, err error) {
-	if fi.rp == len(fi.src) {
-		eof = true
-		return
-	}
-
-	if len(fi.src[fi.rp:]) < 8 {
-		err = errors.Errorf("Record incomplete %v", fi.src)
-		return
-	}
-	fieldOID = binary.BigEndian.Uint32(fi.src[fi.rp:])
-	fi.rp += 4
-
-	fieldLen := int(int32(binary.BigEndian.Uint32(fi.src[fi.rp:])))
-	fi.rp += 4
-
-	if fieldLen >= 0 {
-		if len(fi.src[fi.rp:]) < fieldLen {
-			err = errors.Errorf("Record incomplete rp=%d src=%v", fi.rp, fi.src)
-			return
-		}
-		buf = fi.src[fi.rp : fi.rp+fieldLen]
-		fi.rp += fieldLen
-	}
-
-	return
-}
-
 func prepareNewBinaryDecoder(ci *ConnInfo, fieldOID uint32, v *Value) (BinaryDecoder, error) {
 	var binaryDecoder BinaryDecoder
 
@@ -153,13 +104,13 @@ func (dst *Record) DecodeBinary(ci *ConnInfo, src []byte) error {
 		return nil
 	}
 
-	fieldIter, err := newFieldIterator(src)
+	fieldIter, fieldCount, err := binary.NewRecordFieldIterator(src)
 	if err != nil {
 		return err
 	}
 
-	fields := make([]Value, fieldIter.fieldCount)
+	fields := make([]Value, fieldCount)
-	fieldOID, fieldBytes, eof, err := fieldIter.next()
+	fieldOID, fieldBytes, eof, err := fieldIter.Next()
 
 	for i := 0; !eof; i++ {
 		if err != nil {
@@ -175,7 +126,7 @@ func (dst *Record) DecodeBinary(ci *ConnInfo, src []byte) error {
 			return err
 		}
 
-		fieldOID, fieldBytes, eof, err = fieldIter.next()
+		fieldOID, fieldBytes, eof, err = fieldIter.Next()
 	}
 
 	*dst = Record{Fields: fields, Status: Present}