xorm/dialects/filter.go

79 lines
1.5 KiB
Go

// Copyright 2019 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 dialects
import (
"fmt"
"strings"
"xorm.io/xorm/schemas"
)
// Filter is an interface to filter SQL
type Filter interface {
Do(sql string) string
}
// QuoteFilter filter SQL replace ` to database's own quote character
type QuoteFilter struct {
quoter schemas.Quoter
}
func (s *QuoteFilter) Do(sql string) string {
if s.quoter.IsEmpty() {
return sql
}
var buf strings.Builder
buf.Grow(len(sql))
var beginSingleQuote bool
var prefix = true
for i := 0; i < len(sql); i++ {
if !beginSingleQuote && sql[i] == '`' {
if prefix {
buf.WriteByte(s.quoter.Prefix)
} else {
buf.WriteByte(s.quoter.Suffix)
}
prefix = !prefix
} else {
if sql[i] == '\'' {
beginSingleQuote = !beginSingleQuote
}
buf.WriteByte(sql[i])
}
}
return buf.String()
}
// SeqFilter filter SQL replace ?, ? ... to $1, $2 ...
type SeqFilter struct {
Prefix string
Start int
}
func convertQuestionMark(sql, prefix string, start int) string {
var buf strings.Builder
var beginSingleQuote bool
var index = start
for _, c := range sql {
if !beginSingleQuote && c == '?' {
buf.WriteString(fmt.Sprintf("%s%v", prefix, index))
index++
} else {
if c == '\'' {
beginSingleQuote = !beginSingleQuote
}
buf.WriteRune(c)
}
}
return buf.String()
}
func (s *SeqFilter) Do(sql string) string {
return convertQuestionMark(sql, s.Prefix, s.Start)
}