From e2e802b837a234ede6dc122dbb26de965e35e55f Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Mon, 28 Feb 2022 09:28:19 +0800
Subject: [PATCH] Refactor Scan

---
 callbacks/create.go |  6 ++++--
 scan.go             | 29 ++++++++++++++++-------------
 tests/go.mod        |  2 +-
 3 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/callbacks/create.go b/callbacks/create.go
index b0964e2b..6e2883f7 100644
--- a/callbacks/create.go
+++ b/callbacks/create.go
@@ -201,13 +201,15 @@ func ConvertToCreateValues(stmt *gorm.Statement) (values clause.Values) {
 		switch stmt.ReflectValue.Kind() {
 		case reflect.Slice, reflect.Array:
 			rValLen := stmt.ReflectValue.Len()
-			stmt.SQL.Grow(rValLen * 18)
-			values.Values = make([][]interface{}, rValLen)
 			if rValLen == 0 {
 				stmt.AddError(gorm.ErrEmptySlice)
 				return
 			}
 
+			stmt.SQL.Grow(rValLen * 18)
+			stmt.Vars = make([]interface{}, 0, rValLen*len(values.Columns))
+			values.Values = make([][]interface{}, rValLen)
+
 			defaultValueFieldsHavingValue := map[*schema.Field][]interface{}{}
 			for i := 0; i < rValLen; i++ {
 				rv := reflect.Indirect(stmt.ReflectValue.Index(i))
diff --git a/scan.go b/scan.go
index d7b58e03..a4243d12 100644
--- a/scan.go
+++ b/scan.go
@@ -54,10 +54,6 @@ func (db *DB) scanIntoStruct(rows *sql.Rows, reflectValue reflect.Value, values
 	for idx, field := range fields {
 		if field != nil {
 			values[idx] = field.NewValuePool.Get()
-			defer field.NewValuePool.Put(values[idx])
-			if len(joinFields) == 0 || joinFields[idx][0] == nil {
-				defer field.Set(db.Statement.Context, reflectValue, values[idx])
-			}
 		} else if len(fields) == 1 {
 			if reflectValue.CanAddr() {
 				values[idx] = reflectValue.Addr().Interface()
@@ -70,17 +66,24 @@ func (db *DB) scanIntoStruct(rows *sql.Rows, reflectValue reflect.Value, values
 	db.RowsAffected++
 	db.AddError(rows.Scan(values...))
 
-	for idx, joinField := range joinFields {
-		if joinField[0] != nil {
-			relValue := joinField[0].ReflectValueOf(db.Statement.Context, reflectValue)
-			if relValue.Kind() == reflect.Ptr && relValue.IsNil() {
-				if value := reflect.ValueOf(values[idx]).Elem(); value.Kind() == reflect.Ptr && value.IsNil() {
-					return
-				}
+	for idx, field := range fields {
+		if field != nil {
+			if len(joinFields) == 0 || joinFields[idx][0] == nil {
+				field.Set(db.Statement.Context, reflectValue, values[idx])
+			} else {
+				relValue := joinFields[idx][0].ReflectValueOf(db.Statement.Context, reflectValue)
+				if relValue.Kind() == reflect.Ptr && relValue.IsNil() {
+					if value := reflect.ValueOf(values[idx]).Elem(); value.Kind() == reflect.Ptr && value.IsNil() {
+						return
+					}
 
-				relValue.Set(reflect.New(relValue.Type().Elem()))
+					relValue.Set(reflect.New(relValue.Type().Elem()))
+				}
+				joinFields[idx][1].Set(db.Statement.Context, relValue, values[idx])
 			}
-			joinField[1].Set(db.Statement.Context, relValue, values[idx])
+
+			// release data to pool
+			field.NewValuePool.Put(values[idx])
 		}
 	}
 }
diff --git a/tests/go.mod b/tests/go.mod
index 9e3453b7..c65ea953 100644
--- a/tests/go.mod
+++ b/tests/go.mod
@@ -8,7 +8,7 @@ require (
 	github.com/jackc/pgx/v4 v4.15.0 // indirect
 	github.com/jinzhu/now v1.1.4
 	github.com/lib/pq v1.10.4
-	github.com/mattn/go-sqlite3 v1.14.11 // indirect
+	github.com/mattn/go-sqlite3 v1.14.12 // indirect
 	golang.org/x/crypto v0.0.0-20220214200702-86341886e292 // indirect
 	gorm.io/driver/mysql v1.3.2
 	gorm.io/driver/postgres v1.3.1