update latest xorm version to vendor (#2353)

vendor/github.com/go-xorm/xorm/session_exist.go

@@ -0,0 +1,87 @@
+// Copyright 2017 The Xorm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xorm
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+
+	"github.com/go-xorm/builder"
+	"github.com/go-xorm/core"
+)
+
+// Exist returns true if the record exist otherwise return false
+func (session *Session) Exist(bean ...interface{}) (bool, error) {
+	defer session.resetStatement()
+	if session.isAutoClose {
+		defer session.Close()
+	}
+
+	var sqlStr string
+	var args []interface{}
+	var err error
+
+	if session.statement.RawSQL == "" {
+		if len(bean) == 0 {
+			tableName := session.statement.TableName()
+			if len(tableName) <= 0 {
+				return false, ErrTableNotFound
+			}
+
+			if session.statement.cond.IsValid() {
+				condSQL, condArgs, err := builder.ToSQL(session.statement.cond)
+				if err != nil {
+					return false, err
+				}
+
+				sqlStr = fmt.Sprintf("SELECT * FROM %s WHERE %s LIMIT 1", tableName, condSQL)
+				args = condArgs
+			} else {
+				sqlStr = fmt.Sprintf("SELECT * FROM %s LIMIT 1", tableName)
+				args = []interface{}{}
+			}
+		} else {
+			beanValue := reflect.ValueOf(bean[0])
+			if beanValue.Kind() != reflect.Ptr {
+				return false, errors.New("needs a pointer")
+			}
+
+			if beanValue.Elem().Kind() == reflect.Struct {
+				if err := session.statement.setRefValue(beanValue.Elem()); err != nil {
+					return false, err
+				}
+			}
+
+			if len(session.statement.TableName()) <= 0 {
+				return false, ErrTableNotFound
+			}
+			session.statement.Limit(1)
+			sqlStr, args, err = session.statement.genGetSQL(bean[0])
+			if err != nil {
+				return false, err
+			}
+		}
+	} else {
+		sqlStr = session.statement.RawSQL
+		args = session.statement.RawParams
+	}
+
+	session.queryPreprocess(&sqlStr, args...)
+
+	var rawRows *core.Rows
+	if session.isAutoCommit {
+		_, rawRows, err = session.innerQuery(sqlStr, args...)
+	} else {
+		rawRows, err = session.tx.Query(sqlStr, args...)
+	}
+	if err != nil {
+		return false, err
+	}
+
+	defer rawRows.Close()
+
+	return rawRows.Next(), nil
+}