Merge pull request #42 from Songmu/NamedValueChecker

implement NamedValueChecker

conn_go19.go

@@ -0,0 +1,25 @@
+// +build go1.9
+
+package proxy
+
+import "database/sql/driver"
+
+// copied from sql/driver/convert.go
+// defaultCheckNamedValue wraps the default ColumnConverter to have the same
+// function signature as the CheckNamedValue in the driver.NamedValueChecker
+// interface.
+func defaultCheckNamedValue(nv *driver.NamedValue) (err error) {
+	nv.Value, err = driver.DefaultParameterConverter.ConvertValue(nv.Value)
+	return err
+}
+
+// CheckNamedValue for implementing NamedValueChecker
+// This function may be unnecessary because `proxy.Stmt` already implements `NamedValueChecker`,
+// but it is implemented just in case.
+func (conn *Conn) CheckNamedValue(nv *driver.NamedValue) (err error) {
+	if nvc, ok := conn.Conn.(driver.NamedValueChecker); ok {
+		return nvc.CheckNamedValue(nv)
+	}
+	// fallback to default
+	return defaultCheckNamedValue(nv)
+}

stmt_go19.go

@@ -0,0 +1,21 @@
+// +build go1.9
+
+package proxy
+
+import "database/sql/driver"
+
+// CheckNamedValue for implementing NamedValueChecker
+func (stmt *Stmt) CheckNamedValue(nv *driver.NamedValue) (err error) {
+	if nvc, ok := stmt.Stmt.(driver.NamedValueChecker); ok {
+		return nvc.CheckNamedValue(nv)
+	}
+	// When converting data in sql/driver/convert.go, it is checked first whether the `stmt`
+	// implements `NamedValueChecker`, and then checks if `conn` implements NamedValueChecker.
+	// In the case of "go-sql-proxy", the `proxy.Stmt` "implements" `CheckNamedValue` here,
+	// so we also check both `stmt` and `conn` inside here.
+	if nvc, ok := stmt.Conn.Conn.(driver.NamedValueChecker); ok {
+		return nvc.CheckNamedValue(nv)
+	}
+	// fallback to default
+	return defaultCheckNamedValue(nv)
+}