From 4555796b62fa679f3397d5201759e387f7d88a0c Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Mon, 8 Jun 2020 22:32:35 +0800
Subject: [PATCH] Refactor Execute callbacks

---
 callbacks.go    | 50 ++++++++++++++++++++++++-------------------------
 finisher_api.go | 16 +++++++---------
 2 files changed, 31 insertions(+), 35 deletions(-)

diff --git a/callbacks.go b/callbacks.go
index e6cf29af..5e7933af 100644
--- a/callbacks.go
+++ b/callbacks.go
@@ -73,26 +73,26 @@ func (cs *callbacks) Raw() *processor {
 
 func (p *processor) Execute(db *DB) {
 	curTime := time.Now()
+	stmt := db.Statement
 	db.RowsAffected = 0
-	if stmt := db.Statement; stmt != nil {
-		if stmt.Model == nil {
-			stmt.Model = stmt.Dest
-		}
 
-		if stmt.Model != nil {
-			if err := stmt.Parse(stmt.Model); err != nil && (!errors.Is(err, schema.ErrUnsupportedDataType) || (stmt.Table == "" && stmt.SQL.Len() == 0)) {
-				db.AddError(err)
-			}
-		}
+	if stmt.Model == nil {
+		stmt.Model = stmt.Dest
+	}
 
-		if stmt.Dest != nil {
-			stmt.ReflectValue = reflect.Indirect(reflect.ValueOf(stmt.Dest))
-			for stmt.ReflectValue.Kind() == reflect.Ptr {
-				stmt.ReflectValue = stmt.ReflectValue.Elem()
-			}
-			if !stmt.ReflectValue.IsValid() {
-				db.AddError(fmt.Errorf("invalid value"))
-			}
+	if stmt.Model != nil {
+		if err := stmt.Parse(stmt.Model); err != nil && (!errors.Is(err, schema.ErrUnsupportedDataType) || (stmt.Table == "" && stmt.SQL.Len() == 0)) {
+			db.AddError(err)
+		}
+	}
+
+	if stmt.Dest != nil {
+		stmt.ReflectValue = reflect.ValueOf(stmt.Dest)
+		for stmt.ReflectValue.Kind() == reflect.Ptr {
+			stmt.ReflectValue = stmt.ReflectValue.Elem()
+		}
+		if !stmt.ReflectValue.IsValid() {
+			db.AddError(fmt.Errorf("invalid value"))
 		}
 	}
 
@@ -100,16 +100,14 @@ func (p *processor) Execute(db *DB) {
 		f(db)
 	}
 
-	if stmt := db.Statement; stmt != nil {
-		db.Logger.Trace(stmt.Context, curTime, func() (string, int64) {
-			return db.Dialector.Explain(stmt.SQL.String(), stmt.Vars...), db.RowsAffected
-		}, db.Error)
+	db.Logger.Trace(stmt.Context, curTime, func() (string, int64) {
+		return db.Dialector.Explain(stmt.SQL.String(), stmt.Vars...), db.RowsAffected
+	}, db.Error)
 
-		if !stmt.DB.DryRun {
-			stmt.SQL.Reset()
-			stmt.Vars = nil
-			stmt.NamedVars = nil
-		}
+	if !stmt.DB.DryRun {
+		stmt.SQL.Reset()
+		stmt.Vars = nil
+		stmt.NamedVars = nil
 	}
 }
 
diff --git a/finisher_api.go b/finisher_api.go
index 84890b51..fc21e490 100644
--- a/finisher_api.go
+++ b/finisher_api.go
@@ -51,7 +51,7 @@ func (db *DB) Save(value interface{}) (tx *DB) {
 
 // First find first record that match given conditions, order by primary key
 func (db *DB) First(dest interface{}, conds ...interface{}) (tx *DB) {
-	tx = db.getInstance().Limit(1).Order(clause.OrderByColumn{
+	tx = db.Limit(1).Order(clause.OrderByColumn{
 		Column: clause.Column{Table: clause.CurrentTable, Name: clause.PrimaryKey},
 	})
 	if len(conds) > 0 {
@@ -65,7 +65,7 @@ func (db *DB) First(dest interface{}, conds ...interface{}) (tx *DB) {
 
 // Take return a record that match given conditions, the order will depend on the database implementation
 func (db *DB) Take(dest interface{}, conds ...interface{}) (tx *DB) {
-	tx = db.getInstance().Limit(1)
+	tx = db.Limit(1)
 	if len(conds) > 0 {
 		tx.Statement.AddClause(clause.Where{Exprs: tx.Statement.BuildCondition(conds[0], conds[1:]...)})
 	}
@@ -77,7 +77,7 @@ func (db *DB) Take(dest interface{}, conds ...interface{}) (tx *DB) {
 
 // Last find last record that match given conditions, order by primary key
 func (db *DB) Last(dest interface{}, conds ...interface{}) (tx *DB) {
-	tx = db.getInstance().Limit(1).Order(clause.OrderByColumn{
+	tx = db.Limit(1).Order(clause.OrderByColumn{
 		Column: clause.Column{Table: clause.CurrentTable, Name: clause.PrimaryKey},
 		Desc:   true,
 	})
@@ -120,8 +120,7 @@ func (tx *DB) assignExprsToValue(exprs []clause.Expression) {
 }
 
 func (db *DB) FirstOrInit(dest interface{}, conds ...interface{}) (tx *DB) {
-	tx = db.getInstance()
-	if tx = tx.First(dest, conds...); errors.Is(tx.Error, ErrRecordNotFound) {
+	if tx = db.First(dest, conds...); errors.Is(tx.Error, ErrRecordNotFound) {
 		if c, ok := tx.Statement.Clauses["WHERE"]; ok {
 			if where, ok := c.Expression.(clause.Where); ok {
 				tx.assignExprsToValue(where.Exprs)
@@ -145,8 +144,7 @@ func (db *DB) FirstOrInit(dest interface{}, conds ...interface{}) (tx *DB) {
 }
 
 func (db *DB) FirstOrCreate(dest interface{}, conds ...interface{}) (tx *DB) {
-	tx = db.getInstance()
-	if err := tx.First(dest, conds...).Error; errors.Is(err, ErrRecordNotFound) {
+	if tx = db.First(dest, conds...); errors.Is(tx.Error, ErrRecordNotFound) {
 		tx.Error = nil
 
 		if c, ok := tx.Statement.Clauses["WHERE"]; ok {
@@ -168,7 +166,7 @@ func (db *DB) FirstOrCreate(dest interface{}, conds ...interface{}) (tx *DB) {
 		}
 
 		return tx.Create(dest)
-	} else if len(tx.Statement.assigns) > 0 {
+	} else if len(db.Statement.assigns) > 0 {
 		exprs := tx.Statement.BuildCondition(tx.Statement.assigns[0], tx.Statement.assigns[1:]...)
 		assigns := map[string]interface{}{}
 		for _, expr := range exprs {
@@ -186,7 +184,7 @@ func (db *DB) FirstOrCreate(dest interface{}, conds ...interface{}) (tx *DB) {
 		return tx.Model(dest).Updates(assigns)
 	}
 
-	return
+	return db
 }
 
 // Update update attributes with callbacks, refer: https://jinzhu.github.io/gorm/crud.html#update