From b139307f5bdfab58712841628e701959749523ff Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Sun, 5 Mar 2017 13:05:49 -0600
Subject: [PATCH] Move OID to pgtype

---
 oid.go      | 41 +++++++++++++++++++++++
 oid_test.go | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 pguint32.go |  2 +-
 3 files changed, 136 insertions(+), 1 deletion(-)
 create mode 100644 oid.go
 create mode 100644 oid_test.go

diff --git a/oid.go b/oid.go
new file mode 100644
index 00000000..d137f352
--- /dev/null
+++ b/oid.go
@@ -0,0 +1,41 @@
+package pgtype
+
+import (
+	"io"
+)
+
+// OID (Object Identifier Type) is, according to
+// https://www.postgresql.org/docs/current/static/datatype-oid.html, used
+// internally by PostgreSQL as a primary key for various system tables. It is
+// currently implemented as an unsigned four-byte integer. Its definition can be
+// found in src/include/postgres_ext.h in the PostgreSQL sources.
+type OID pguint32
+
+// ConvertFrom converts from src to dst. Note that as OID is not a general
+// number type ConvertFrom does not do automatic type conversion as other number
+// types do.
+func (dst *OID) ConvertFrom(src interface{}) error {
+	return (*pguint32)(dst).ConvertFrom(src)
+}
+
+// AssignTo assigns from src to dst. Note that as OID is not a general number
+// type AssignTo does not do automatic type conversion as other number types do.
+func (src *OID) AssignTo(dst interface{}) error {
+	return (*pguint32)(src).AssignTo(dst)
+}
+
+func (dst *OID) DecodeText(r io.Reader) error {
+	return (*pguint32)(dst).DecodeText(r)
+}
+
+func (dst *OID) DecodeBinary(r io.Reader) error {
+	return (*pguint32)(dst).DecodeBinary(r)
+}
+
+func (src OID) EncodeText(w io.Writer) error {
+	return (pguint32)(src).EncodeText(w)
+}
+
+func (src OID) EncodeBinary(w io.Writer) error {
+	return (pguint32)(src).EncodeBinary(w)
+}
diff --git a/oid_test.go b/oid_test.go
new file mode 100644
index 00000000..c8e0b2d6
--- /dev/null
+++ b/oid_test.go
@@ -0,0 +1,94 @@
+package pgtype_test
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/jackc/pgx/pgtype"
+)
+
+func TestOIDTranscode(t *testing.T) {
+	testSuccessfulTranscode(t, "oid", []interface{}{
+		pgtype.OID{Uint: 42, Status: pgtype.Present},
+		pgtype.OID{Status: pgtype.Null},
+	})
+}
+
+func TestOIDConvertFrom(t *testing.T) {
+	successfulTests := []struct {
+		source interface{}
+		result pgtype.OID
+	}{
+		{source: uint32(1), result: pgtype.OID{Uint: 1, Status: pgtype.Present}},
+	}
+
+	for i, tt := range successfulTests {
+		var r pgtype.OID
+		err := r.ConvertFrom(tt.source)
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if r != tt.result {
+			t.Errorf("%d: expected %v to convert to %v, but it was %v", i, tt.source, tt.result, r)
+		}
+	}
+}
+
+func TestOIDAssignTo(t *testing.T) {
+	var ui32 uint32
+	var pui32 *uint32
+
+	simpleTests := []struct {
+		src      pgtype.OID
+		dst      interface{}
+		expected interface{}
+	}{
+		{src: pgtype.OID{Uint: 42, Status: pgtype.Present}, dst: &ui32, expected: uint32(42)},
+		{src: pgtype.OID{Status: pgtype.Null}, dst: &pui32, expected: ((*uint32)(nil))},
+	}
+
+	for i, tt := range simpleTests {
+		err := tt.src.AssignTo(tt.dst)
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if dst := reflect.ValueOf(tt.dst).Elem().Interface(); dst != tt.expected {
+			t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, dst)
+		}
+	}
+
+	pointerAllocTests := []struct {
+		src      pgtype.OID
+		dst      interface{}
+		expected interface{}
+	}{
+		{src: pgtype.OID{Uint: 42, Status: pgtype.Present}, dst: &pui32, expected: uint32(42)},
+	}
+
+	for i, tt := range pointerAllocTests {
+		err := tt.src.AssignTo(tt.dst)
+		if err != nil {
+			t.Errorf("%d: %v", i, err)
+		}
+
+		if dst := reflect.ValueOf(tt.dst).Elem().Elem().Interface(); dst != tt.expected {
+			t.Errorf("%d: expected %v to assign %v, but result was %v", i, tt.src, tt.expected, dst)
+		}
+	}
+
+	errorTests := []struct {
+		src pgtype.OID
+		dst interface{}
+	}{
+		{src: pgtype.OID{Status: pgtype.Null}, dst: &ui32},
+	}
+
+	for i, tt := range errorTests {
+		err := tt.src.AssignTo(tt.dst)
+		if err == nil {
+			t.Errorf("%d: expected error but none was returned (%v -> %v)", i, tt.src, tt.dst)
+		}
+	}
+}
diff --git a/pguint32.go b/pguint32.go
index 66b385fb..9c1ccd6c 100644
--- a/pguint32.go
+++ b/pguint32.go
@@ -89,7 +89,7 @@ func (dst *pguint32) DecodeBinary(r io.Reader) error {
 	}
 
 	if size != 4 {
-		return fmt.Errorf("invalid length for cid: %v", size)
+		return fmt.Errorf("invalid length: %v", size)
 	}
 
 	n, err := pgio.ReadUint32(r)