Add NullJSONText type

Taik · Taik · commit 041545bf62ab · 2016-11-09T13:55:52.000-05:00
diff --git a/types/types.go b/types/types.go
@@ -121,6 +121,32 @@ func (j JSONText) String() string {
 	return string(j)
 }
 
+// NullJSONText represents a JSONText that may be null.
+// NullJSONText implements the scanner interface so
+// it can be used as a scan destination, similar to NullString.
+type NullJSONText struct {
+	JSONText
+	Valid bool // Valid is true if JSONText is not NULL
+}
+
+// Scan implements the Scanner interface.
+func (n *NullJSONText) Scan(value interface{}) error {
+	if value == nil {
+		n.JSONText, n.Valid = _EMPTY_JSON, false
+		return nil
+	}
+	n.Valid = true
+	return n.JSONText.Scan(value)
+}
+
+// Value implements the driver Valuer interface.
+func (n *NullJSONText) Value() (driver.Value, error) {
+	if !n.Valid {
+		return nil, nil
+	}
+	return n.JSONText.Value()
+}
+
 // BitBool is an implementation of a bool for the MySQL type BIT(1).
 // This type allows you to avoid wasting an entire byte for MySQL's boolean type TINYINT.
 type BitBool bool
diff --git a/types/types_test.go b/types/types_test.go
@@ -63,6 +63,37 @@ func TestJSONText(t *testing.T) {
 	}
 }
 
+func TestNullJSONText(t *testing.T) {
+	j := NullJSONText{}
+	err := j.Scan(`{"foo": 1, "bar": 2}`)
+	if err != nil {
+		t.Errorf("Was not expecting an error")
+	}
+	v, err := j.Value()
+	if err != nil {
+		t.Errorf("Was not expecting an error")
+	}
+	err = (&j).Scan(v)
+	if err != nil {
+		t.Errorf("Was not expecting an error")
+	}
+	m := map[string]interface{}{}
+	j.Unmarshal(&m)
+
+	if m["foo"].(float64) != 1 || m["bar"].(float64) != 2 {
+		t.Errorf("Expected valid json but got some garbage instead? %#v", m)
+	}
+
+	j = NullJSONText{}
+	err = j.Scan(nil)
+	if err != nil {
+		t.Errorf("Was not expecting an error")
+	}
+	if j.Valid != false {
+		t.Errorf("Expected valid to be false, but got true")
+	}
+}
+
 func TestBitBool(t *testing.T) {
 	// Test true value
 	var b BitBool = true
