From 4faf97cc588126dda160fc360680719572a23105 Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Fri, 17 Feb 2017 22:20:18 -0600
Subject: [PATCH] wip

---
 query.go  | 11 ++++++++++-
 values.go | 18 ++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/query.go b/query.go
index 99b383e0..3bf1a87c 100644
--- a/query.go
+++ b/query.go
@@ -219,6 +219,15 @@ func (rows *Rows) Scan(dest ...interface{}) (err error) {
 			if err != nil {
 				rows.Fatal(scanArgError{col: i, err: err})
 			}
+		} else if s, ok := d.(ScannerV3); ok {
+			val, err := decodeByOID(vr)
+			if err != nil {
+				rows.Fatal(scanArgError{col: i, err: err})
+			}
+			err = s.ScanPgxV3(nil, val)
+			if err != nil {
+				rows.Fatal(scanArgError{col: i, err: err})
+			}
 		} else if s, ok := d.(sql.Scanner); ok {
 			var val interface{}
 			if 0 <= vr.Len() {
@@ -296,7 +305,7 @@ func (rows *Rows) Values() ([]interface{}, error) {
 			values = append(values, nil)
 			continue
 		}
-
+		// TODO - consider what are the implications of returning complex types since database/sql uses this method
 		switch vr.Type().FormatCode {
 		// All intrinsic types (except string) are encoded with binary
 		// encoding so anything else should be treated as a string
diff --git a/values.go b/values.go
index 45ed914c..4606bcb3 100644
--- a/values.go
+++ b/values.go
@@ -200,6 +200,10 @@ type Encoder interface {
 	FormatCode() int16
 }
 
+type ScannerV3 interface {
+	ScanPgxV3(fieldDescription interface{}, src interface{}) error
+}
+
 // NullFloat32 represents an float4 that may be null. NullFloat32 implements the
 // Scanner and Encoder interfaces so it may be used both as an argument to
 // Query[Row] and a destination for Scan.
@@ -1166,6 +1170,20 @@ func stripNamedType(val *reflect.Value) (interface{}, bool) {
 	return nil, false
 }
 
+func decodeByOID(vr *ValueReader) (interface{}, error) {
+	switch vr.Type().DataType {
+	case Int2OID, Int4OID, Int8OID:
+		n := decodeInt(vr)
+		return n, vr.Err()
+	case BoolOID:
+		b := decodeBool(vr)
+		return b, vr.Err()
+	default:
+		buf := vr.ReadBytes(vr.Len())
+		return buf, vr.Err()
+	}
+}
+
 // Decode decodes from vr into d. d must be a pointer. This allows
 // implementations of the Decoder interface to delegate the actual work of
 // decoding to the built-in functionality.