From 439784b33b61f80ff6d34511793d7f544c0dd35b Mon Sep 17 00:00:00 2001
From: Lunny Xiao <xiaolunwen@gmail.com>
Date: Sat, 29 Feb 2020 13:17:34 +0800
Subject: [PATCH] remove unused codes

---
 core/db.go            |  2 +-
 dialects/dialect.go   |  7 -------
 engine.go             | 40 ++++++++++++++++------------------------
 log/logger_context.go | 16 ++++++++++++++--
 4 files changed, 31 insertions(+), 34 deletions(-)

diff --git a/core/db.go b/core/db.go
index ebd3f689..592ccf18 100644
--- a/core/db.go
+++ b/core/db.go
@@ -83,7 +83,7 @@ type DB struct {
 	Mapper            names.Mapper
 	reflectCache      map[reflect.Type]*cacheStruct
 	reflectCacheMutex sync.RWMutex
-	Logger            log.ContextLogger
+	Logger            log.SQLLogger
 }
 
 // Open opens a database
diff --git a/dialects/dialect.go b/dialects/dialect.go
index 4fbc4754..186f94be 100644
--- a/dialects/dialect.go
+++ b/dialects/dialect.go
@@ -11,7 +11,6 @@ import (
 	"time"
 
 	"xorm.io/xorm/core"
-	"xorm.io/xorm/log"
 	"xorm.io/xorm/schemas"
 )
 
@@ -34,7 +33,6 @@ type URI struct {
 
 // a dialect is a driver's wrapper
 type Dialect interface {
-	SetLogger(logger log.ContextLogger)
 	Init(*core.DB, *URI, string, string) error
 	URI() *URI
 	DB() *core.DB
@@ -92,7 +90,6 @@ type Base struct {
 	dialect        Dialect
 	driverName     string
 	dataSourceName string
-	logger         log.ContextLogger
 	uri            *URI
 }
 
@@ -100,10 +97,6 @@ func (b *Base) DB() *core.DB {
 	return b.db
 }
 
-func (b *Base) SetLogger(logger log.ContextLogger) {
-	b.logger = logger
-}
-
 func (b *Base) DefaultSchema() string {
 	return ""
 }
diff --git a/engine.go b/engine.go
index 89ae89cf..f40ce2e4 100644
--- a/engine.go
+++ b/engine.go
@@ -31,22 +31,16 @@ import (
 // Engine is the major struct of xorm, it means a database manager.
 // Commonly, an application only need one engine
 type Engine struct {
-	db      *core.DB
-	dialect dialects.Dialect
+	cacherMgr      *caches.Manager
+	db             *core.DB
+	defaultContext context.Context
+	dialect        dialects.Dialect
+	engineGroup    *EngineGroup
+	logger         log.ContextLogger
+	tagParser      *tags.Parser
 
-	//showSQL      bool
-	//showExecTime bool
-
-	logger     log.ContextLogger
 	TZLocation *time.Location // The timezone of the application
 	DatabaseTZ *time.Location // The timezone of the database
-
-	engineGroup *EngineGroup
-
-	defaultContext context.Context
-
-	tagParser *tags.Parser
-	cacherMgr *caches.Manager
 }
 
 func (engine *Engine) SetCacher(tableName string, cacher caches.Cacher) {
@@ -67,16 +61,12 @@ func (engine *Engine) BufferSize(size int) *Session {
 // ShowSQL show SQL statement or not on logger if log level is great than INFO
 func (engine *Engine) ShowSQL(show ...bool) {
 	engine.logger.ShowSQL(show...)
-}
-
-// ShowExecTime show SQL statement and execute time or not on logger if log level is great than INFO
-/*func (engine *Engine) ShowExecTime(show ...bool) {
-	if len(show) == 0 {
-		engine.showExecTime = true
+	if engine.logger.IsShowSQL() {
+		engine.db.Logger = engine.logger
 	} else {
-		engine.showExecTime = show[0]
+		engine.db.Logger = &log.DiscardSQLLogger{}
 	}
-}*/
+}
 
 // Logger return the logger interface
 func (engine *Engine) Logger() log.ContextLogger {
@@ -93,9 +83,11 @@ func (engine *Engine) SetLogger(logger interface{}) {
 		realLogger = t
 	}
 	engine.logger = realLogger
-	//engine.showSQL = realLogger.IsShowSQL()
-	engine.dialect.SetLogger(realLogger)
-	engine.db.Logger = realLogger
+	if realLogger.IsShowSQL() {
+		engine.db.Logger = realLogger
+	} else {
+		engine.db.Logger = &log.DiscardSQLLogger{}
+	}
 }
 
 // SetLogLevel sets the logger level
diff --git a/log/logger_context.go b/log/logger_context.go
index d9f18682..b05f1c52 100644
--- a/log/logger_context.go
+++ b/log/logger_context.go
@@ -18,14 +18,26 @@ type LogContext struct {
 	Err         error // SQL executed error
 }
 
+type SQLLogger interface {
+	BeforeSQL(context LogContext)
+	AfterSQL(context LogContext)
+}
+
+type DiscardSQLLogger struct{}
+
+var _ SQLLogger = &DiscardSQLLogger{}
+
+func (DiscardSQLLogger) BeforeSQL(LogContext) {}
+func (DiscardSQLLogger) AfterSQL(LogContext)  {}
+
 // ContextLogger represents a logger interface with context
 type ContextLogger interface {
+	SQLLogger
+
 	Debugf(format string, v ...interface{})
 	Errorf(format string, v ...interface{})
 	Infof(format string, v ...interface{})
 	Warnf(format string, v ...interface{})
-	BeforeSQL(context LogContext)
-	AfterSQL(context LogContext)
 
 	Level() LogLevel
 	SetLevel(l LogLevel)