Refactor

main.go

@@ -11,21 +11,23 @@ import (
 
 // DB contains information for current db connection
 type DB struct {
-	Value             interface{}
-	Error             error
-	RowsAffected      int64
-	callbacks         *Callback
+	Value        interface{}
+	Error        error
+	RowsAffected int64
+
+	// single db
 	db                sqlCommon
-	parent            *DB
-	search            *search
+	blockGlobalUpdate bool
 	logMode           int
 	logger            logger
-	dialect           Dialect
-	singularTable     bool
-	source            string
+	search            *search
 	values            map[string]interface{}
-	joinTableHandlers map[string]JoinTableHandler
-	blockGlobalUpdate bool
+
+	// global db
+	parent        *DB
+	callbacks     *Callback
+	dialect       Dialect
+	singularTable bool
 }
 
 // Open initialize a new db connection, need to import driver first, e.g:
@@ -39,16 +41,13 @@ type DB struct {
 //    // import _ "github.com/jinzhu/gorm/dialects/postgres"
 //    // import _ "github.com/jinzhu/gorm/dialects/sqlite"
 //    // import _ "github.com/jinzhu/gorm/dialects/mssql"
-func Open(dialect string, args ...interface{}) (*DB, error) {
-	var db DB
-	var err error
-
+func Open(dialect string, args ...interface{}) (db *DB, err error) {
 	if len(args) == 0 {
 		err = errors.New("invalid database source")
 		return nil, err
 	}
 	var source string
-	var dbSQL sqlCommon
+	var dbSQL *sql.DB
 
 	switch value := args[0].(type) {
 	case string:
@@ -60,44 +59,27 @@ func Open(dialect string, args ...interface{}) (*DB, error) {
 			source = args[1].(string)
 		}
 		dbSQL, err = sql.Open(driver, source)
-	case sqlCommon:
+	case *sql.DB:
 		source = reflect.Indirect(reflect.ValueOf(value)).FieldByName("dsn").String()
 		dbSQL = value
 	}
 
-	db = DB{
-		dialect:   newDialect(dialect, dbSQL.(*sql.DB)),
-		logger:    defaultLogger,
-		callbacks: DefaultCallback,
-		source:    source,
-		values:    map[string]interface{}{},
+	db = &DB{
 		db:        dbSQL,
+		logger:    defaultLogger,
+		values:    map[string]interface{}{},
+		callbacks: DefaultCallback,
+		dialect:   newDialect(dialect, dbSQL),
 	}
-	db.parent = &db
+	db.parent = db
 
 	if err == nil {
-		err = db.DB().Ping() // Send a ping to make sure the database connection is alive.
-		if err != nil {
+		// Send a ping to make sure the database connection is alive.
+		if err = db.DB().Ping(); err != nil {
 			db.DB().Close()
 		}
 	}
-
-	return &db, err
-}
-
-// Close close current db connection
-func (s *DB) Close() error {
-	return s.parent.db.(*sql.DB).Close()
-}
-
-// DB get `*sql.DB` from current connection
-func (s *DB) DB() *sql.DB {
-	return s.db.(*sql.DB)
-}
-
-// Dialect get dialect
-func (s *DB) Dialect() Dialect {
-	return s.parent.dialect
+	return
 }
 
 // New clone a new db connection without search conditions
@@ -108,11 +90,17 @@ func (s *DB) New() *DB {
 	return clone
 }
 
-// NewScope create a scope for current operation
-func (s *DB) NewScope(value interface{}) *Scope {
-	dbClone := s.clone()
-	dbClone.Value = value
-	return &Scope{db: dbClone, Search: dbClone.search.clone(), Value: value}
+// Close close current db connection
+func (s *DB) Close() error {
+	if db, ok := s.parent.db.(*sql.DB); ok {
+		return db.Close()
+	}
+	return errors.New("can't close current db")
+}
+
+// DB get `*sql.DB` from current connection
+func (s *DB) DB() *sql.DB {
+	return s.db.(*sql.DB)
 }
 
 // CommonDB return the underlying `*sql.DB` or `*sql.Tx` instance, mainly intended to allow coexistence with legacy non-GORM code.
@@ -120,6 +108,11 @@ func (s *DB) CommonDB() sqlCommon {
 	return s.db
 }
 
+// Dialect get dialect
+func (s *DB) Dialect() Dialect {
+	return s.parent.dialect
+}
+
 // Callback return `Callbacks` container, you could add/change/delete callbacks with it
 //     db.Callback().Create().Register("update_created_at", updateCreated)
 // Refer https://jinzhu.github.io/gorm/development.html#callbacks
@@ -161,6 +154,13 @@ func (s *DB) SingularTable(enable bool) {
 	s.parent.singularTable = enable
 }
 
+// NewScope create a scope for current operation
+func (s *DB) NewScope(value interface{}) *Scope {
+	dbClone := s.clone()
+	dbClone.Value = value
+	return &Scope{db: dbClone, Search: dbClone.search.clone(), Value: value}
+}
+
 // Where return a new relation, filter records with given conditions, accepts `map`, `struct` or `string` as conditions, refer http://jinzhu.github.io/gorm/crud.html#query
 func (s *DB) Where(query interface{}, args ...interface{}) *DB {
 	return s.clone().search.Where(query, args...).db
@@ -691,7 +691,7 @@ func (s *DB) GetErrors() []error {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// Private Methods For *gorm.DB
+// Private Methods For DB
 ////////////////////////////////////////////////////////////////////////////////
 
 func (s *DB) clone() *DB {
@@ -721,7 +721,7 @@ func (s *DB) clone() *DB {
 }
 
 func (s *DB) print(v ...interface{}) {
-	s.logger.(logger).Print(v...)
+	s.logger.Print(v...)
 }
 
 func (s *DB) log(v ...interface{}) {