xorm/dialects/filter.go
2021-07-05 11:36:40 +08:00

77 lines
1.7 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"
)
// Filter is an interface to filter SQL
type Filter interface {
Do(sql string) 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 isLineComment bool
var isComment bool
var isMaybeLineComment bool
var isMaybeComment bool
var isMaybeCommentEnd bool
var index = start
for _, c := range sql {
if !beginSingleQuote && !isLineComment && !isComment && c == '?' {
buf.WriteString(fmt.Sprintf("%s%v", prefix, index))
index++
} else {
if isMaybeLineComment {
if c == '-' {
isLineComment = true
}
isMaybeLineComment = false
} else if isMaybeComment {
if c == '*' {
isComment = true
}
isMaybeComment = false
} else if isMaybeCommentEnd {
if c == '/' {
isComment = false
}
isMaybeCommentEnd = false
} else if isLineComment {
if c == '\n' {
isLineComment = false
}
} else if isComment {
if c == '*' {
isMaybeCommentEnd = true
}
} else if !beginSingleQuote && c == '-' {
isMaybeLineComment = true
} else if !beginSingleQuote && c == '/' {
isMaybeComment = true
} else if c == '\'' {
beginSingleQuote = !beginSingleQuote
}
buf.WriteRune(c)
}
}
return buf.String()
}
// Do implements Filter
func (s *SeqFilter) Do(sql string) string {
return convertQuestionMark(sql, s.Prefix, s.Start)
}