Transaction in callbacks

README.md

@@ -598,16 +598,43 @@ db.Select("name, age").Find(&users)
 ## Callbacks
 
 Callbacks are functions defined to struct's pointer, they would be run when save a struct to database.
-If any callback return error, gorm will stop future operations and do rollback
+If any callback return error, gorm will stop future operations and rollback all changes
 
-Below callbacks are supported now:
+Here is a list with all available callbacks,
+listed in the same order in which they will get called during the respective operations.
 
-`BeforeCreate`, `AfterCreate`
-`BeforeUpdate`, `AfterUpdate`
-`BeforeSave`, `AfterSave`
-`BeforeDelete`, `AfterDelete`
+### Creating an Object
 
-For example:
+```go
+BeforeSave
+BeforeCreate
+// save before associations
+// save self
+// save after associations
+AfterCreate
+AfterSave
+```
+### Updating an Object
+
+```go
+BeforeSave
+BeforeUpdate
+// save before associations
+// save self
+// save after associations
+AfterUpdate
+AfterSave
+```
+
+### Destroying an Object
+
+```go
+BeforeDelete
+// delete self
+AfterDelete
+```
+
+Here is an example:
 
 ```go
 func (u *User) BeforeUpdate() (err error) {
@@ -626,6 +653,17 @@ func (u *User) AfterCreate() (err error) {
 }
 ```
 
+```go
+// As you know, the save/delete operations are running in a transaction
+// This is means all your changes will be rollbacked if get any errors
+// If you want your changes in callbacks be run in the same transaction
+// You have to pass the transaction as argument to the function
+func (u *User) AfterCreate(tx *gorm.DB) (err error) {
+    tx.Model(u).Update("role", "admin")
+    return
+}
+```
+
 ## Specify Table Name
 
 ```go

do.go

@@ -173,8 +173,8 @@ func (s *Do) saveAfterAssociations() {
 
 func (s *Do) create() (i interface{}) {
 	defer s.trace(time.Now())
-	s.model.callMethod("BeforeCreate")
 	s.model.callMethod("BeforeSave")
+	s.model.callMethod("BeforeCreate")
 
 	s.saveBeforeAssociations()
 	s.prepareCreateSql()
@@ -274,8 +274,8 @@ func (s *Do) update() *Do {
 		return s
 	}
 
-	s.model.callMethod("BeforeUpdate")
 	s.model.callMethod("BeforeSave")
+	s.model.callMethod("BeforeUpdate")
 	s.saveBeforeAssociations()
 
 	s.prepareUpdateSql(true)

gorm_test.go

@@ -588,8 +588,8 @@ func (s *Product) BeforeSave() (err error) {
 	return
 }
 
-func (s *Product) AfterCreate() {
-	s.AfterCreateCallTimes = s.AfterCreateCallTimes + 1
+func (s *Product) AfterCreate(db *DB) {
+	db.Model(s).UpdateColumn(Product{AfterCreateCallTimes: s.AfterCreateCallTimes + 1})
 }
 
 func (s *Product) AfterUpdate() {
@@ -633,23 +633,23 @@ func TestRunCallbacks(t *testing.T) {
 	}
 
 	db.Where("Code = ?", "unique_code").First(&p)
-	if !reflect.DeepEqual(p.GetCallTimes(), []int64{1, 1, 0, 0, 0, 0, 0, 0}) {
+	if !reflect.DeepEqual(p.GetCallTimes(), []int64{1, 1, 0, 1, 0, 0, 0, 0}) {
 		t.Errorf("After callbacks values are not saved, %v", p.GetCallTimes())
 	}
 
 	p.Price = 200
 	db.Save(&p)
-	if !reflect.DeepEqual(p.GetCallTimes(), []int64{1, 2, 1, 0, 1, 1, 0, 0}) {
+	if !reflect.DeepEqual(p.GetCallTimes(), []int64{1, 2, 1, 1, 1, 1, 0, 0}) {
 		t.Errorf("After update callbacks should be invoked successfully, %v", p.GetCallTimes())
 	}
 
 	db.Where("Code = ?", "unique_code").First(&p)
-	if !reflect.DeepEqual(p.GetCallTimes(), []int64{1, 2, 1, 0, 0, 0, 0, 0}) {
+	if !reflect.DeepEqual(p.GetCallTimes(), []int64{1, 2, 1, 1, 0, 0, 0, 0}) {
 		t.Errorf("After update callbacks values are not saved, %v", p.GetCallTimes())
 	}
 
 	db.Delete(&p)
-	if !reflect.DeepEqual(p.GetCallTimes(), []int64{1, 2, 1, 0, 0, 0, 1, 1}) {
+	if !reflect.DeepEqual(p.GetCallTimes(), []int64{1, 2, 1, 1, 0, 0, 1, 1}) {
 		t.Errorf("After delete callbacks should be invoked successfully, %v", p.GetCallTimes())
 	}
 

model.go

@@ -239,8 +239,15 @@ func (m *Model) callMethod(method string) {
 	}
 
 	if fm := reflect.ValueOf(m.data).MethodByName(method); fm.IsValid() {
-		if v := fm.Call([]reflect.Value{}); len(v) > 0 {
-			if verr, ok := v[0].Interface().(error); ok {
+		numin := fm.Type().NumIn()
+		var results []reflect.Value
+		if numin == 0 {
+			results = fm.Call([]reflect.Value{})
+		} else if numin == 1 {
+			results = fm.Call([]reflect.Value{reflect.ValueOf(m.do.db.new())})
+		}
+		if len(results) > 0 {
+			if verr, ok := results[0].Interface().(error); ok {
 				m.do.err(verr)
 			}
 		}

private.go

@@ -18,6 +18,12 @@ func (s *DB) clone() *DB {
 	return &db
 }
 
+func (s *DB) new() *DB {
+	db := DB{db: s.db, parent: s.parent, logMode: s.logMode, data: s.data, Error: s.Error, search: &search{}}
+	db.search.db = &db
+	return &db
+}
+
 func (s *DB) do(data interface{}) *Do {
 	s.data = data
 	do := Do{db: s}