Filter support passing context (#2200) (#2270)

```diff
// Filter is an interface to filter SQL
type Filter interface {
---	Do(sql string) string
+++	Do(ctx context.Context, sql string) string
}
```

### Adds a `Context` parameter to the `Do` method of the Filter interface.

Developers can rewrite SQL through the `Filter` `Do` method and **need to get the necessary data from the Context** to assist.

For example, get user information through `Context`, so that different users can use different tables. Another example is to get the flags through `Context` to add annotations to the SQL, and use the annotations to let the subsequent `DB-Proxy` to achieve read/write separation.

Reviewed-on: https://gitea.com/xorm/xorm/pulls/2270
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: LinkinStars <linkinstar@foxmail.com>
Co-committed-by: LinkinStars <linkinstar@foxmail.com>

dialects/filter.go

@@ -5,13 +5,14 @@
 package dialects
 
 import (
+	"context"
 	"fmt"
 	"strings"
 )
 
 // Filter is an interface to filter SQL
 type Filter interface {
-	Do(sql string) string
+	Do(ctx context.Context, sql string) string
 }
 
 // SeqFilter filter SQL replace ?, ? ... to $1, $2 ...
@@ -71,6 +72,6 @@ func convertQuestionMark(sql, prefix string, start int) string {
 }
 
 // Do implements Filter
-func (s *SeqFilter) Do(sql string) string {
+func (s *SeqFilter) Do(ctx context.Context, sql string) string {
 	return convertQuestionMark(sql, s.Prefix, s.Start)
 }

session_delete.go

@@ -30,7 +30,7 @@ func (session *Session) cacheDelete(table *schemas.Table, tableName, sqlStr stri
 	}
 
 	for _, filter := range session.engine.dialect.Filters() {
-		sqlStr = filter.Do(sqlStr)
+		sqlStr = filter.Do(session.ctx, sqlStr)
 	}
 
 	newsql := session.statement.ConvertIDSQL(sqlStr)

session_find.go

@@ -283,7 +283,7 @@ func (session *Session) cacheFind(t reflect.Type, sqlStr string, rowsSlicePtr in
 	}
 
 	for _, filter := range session.engine.dialect.Filters() {
-		sqlStr = filter.Do(sqlStr)
+		sqlStr = filter.Do(session.ctx, sqlStr)
 	}
 
 	newsql := session.statement.ConvertIDSQL(sqlStr)

session_get.go

@@ -278,7 +278,7 @@ func (session *Session) cacheGet(bean interface{}, sqlStr string, args ...interf
 	}
 
 	for _, filter := range session.engine.dialect.Filters() {
-		sqlStr = filter.Do(sqlStr)
+		sqlStr = filter.Do(session.ctx, sqlStr)
 	}
 	newsql := session.statement.ConvertIDSQL(sqlStr)
 	if newsql == "" {

session_raw.go

@@ -13,7 +13,7 @@ import (
 
 func (session *Session) queryPreprocess(sqlStr *string, paramStr ...interface{}) {
 	for _, filter := range session.engine.dialect.Filters() {
-		*sqlStr = filter.Do(*sqlStr)
+		*sqlStr = filter.Do(session.ctx, *sqlStr)
 	}
 
 	session.lastSQL = *sqlStr

session_update.go

@@ -34,7 +34,7 @@ func (session *Session) cacheUpdate(table *schemas.Table, tableName, sqlStr stri
 		return ErrCacheFailed
 	}
 	for _, filter := range session.engine.dialect.Filters() {
-		newsql = filter.Do(newsql)
+		newsql = filter.Do(session.ctx, newsql)
 	}
 	session.engine.logger.Debugf("[cache] new sql: %v, %v", oldhead, newsql)