Add bytea

pgtype/bytea.go

@@ -0,0 +1,160 @@
+package pgtype
+
+import (
+	"encoding/hex"
+	"fmt"
+	"io"
+	"reflect"
+
+	"github.com/jackc/pgx/pgio"
+)
+
+type Bytea struct {
+	Bytes  []byte
+	Status Status
+}
+
+func (dst *Bytea) ConvertFrom(src interface{}) error {
+	switch value := src.(type) {
+	case Bytea:
+		*dst = value
+	case []byte:
+		if value != nil {
+			*dst = Bytea{Bytes: value, Status: Present}
+		} else {
+			*dst = Bytea{Status: Null}
+		}
+	default:
+		if originalSrc, ok := underlyingBytesType(src); ok {
+			return dst.ConvertFrom(originalSrc)
+		}
+		return fmt.Errorf("cannot convert %v to Bytea", value)
+	}
+
+	return nil
+}
+
+func (src *Bytea) AssignTo(dst interface{}) error {
+	switch v := dst.(type) {
+	case *[]byte:
+		if src.Status == Present {
+			*v = src.Bytes
+		} else {
+			*v = nil
+		}
+	default:
+		if v := reflect.ValueOf(dst); v.Kind() == reflect.Ptr {
+			el := v.Elem()
+			switch el.Kind() {
+			// if dst is a pointer to pointer, strip the pointer and try again
+			case reflect.Ptr:
+				if src.Status == Null {
+					el.Set(reflect.Zero(el.Type()))
+					return nil
+				}
+				if el.IsNil() {
+					// allocate destination
+					el.Set(reflect.New(el.Type().Elem()))
+				}
+				return src.AssignTo(el.Interface())
+			default:
+				if originalDst, ok := underlyingPtrSliceType(dst); ok {
+					return src.AssignTo(originalDst)
+				}
+			}
+		}
+		return fmt.Errorf("cannot decode %v into %T", src, dst)
+	}
+
+	return nil
+}
+
+// DecodeText only supports the hex format. This has been the default since
+// PostgreSQL 9.0.
+func (dst *Bytea) DecodeText(r io.Reader) error {
+	size, err := pgio.ReadInt32(r)
+	if err != nil {
+		return err
+	}
+
+	if size == -1 {
+		*dst = Bytea{Status: Null}
+		return nil
+	}
+
+	sbuf := make([]byte, int(size))
+	_, err = io.ReadFull(r, sbuf)
+	if err != nil {
+		return err
+	}
+
+	if len(sbuf) < 2 || sbuf[0] != '\\' || sbuf[1] != 'x' {
+		return fmt.Errorf("invalid hex format")
+	}
+
+	buf := make([]byte, (len(sbuf)-2)/2)
+	_, err = hex.Decode(buf, sbuf[2:])
+	if err != nil {
+		return err
+	}
+
+	*dst = Bytea{Bytes: buf, Status: Present}
+	return nil
+}
+
+func (dst *Bytea) DecodeBinary(r io.Reader) error {
+	size, err := pgio.ReadInt32(r)
+	if err != nil {
+		return err
+	}
+
+	if size == -1 {
+		*dst = Bytea{Status: Null}
+		return nil
+	}
+
+	buf := make([]byte, int(size))
+
+	_, err = io.ReadFull(r, buf)
+	if err != nil {
+		return err
+	}
+
+	*dst = Bytea{Bytes: buf, Status: Present}
+	return nil
+}
+
+func (src Bytea) EncodeText(w io.Writer) error {
+	if done, err := encodeNotPresent(w, src.Status); done {
+		return err
+	}
+
+	str := hex.EncodeToString(src.Bytes)
+
+	_, err := pgio.WriteInt32(w, int32(len(str)+2))
+	if err != nil {
+		return nil
+	}
+
+	_, err = io.WriteString(w, `\x`)
+	if err != nil {
+		return nil
+	}
+
+	_, err = io.WriteString(w, str)
+	return err
+}
+
+func (src Bytea) EncodeBinary(w io.Writer) error {
+	if done, err := encodeNotPresent(w, src.Status); done {
+		return err
+	}
+
+	_, err := pgio.WriteInt32(w, int32(len(src.Bytes)))
+	if err != nil {
+		return nil
+	}
+
+	_, err = w.Write(src.Bytes)
+	return err
+}