Lightweight & Compitable wrapper of database/sql
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// 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 core
import (
"fmt"
"strings"
)
// Filter is an interface to filter SQL
type Filter interface {
Do(sql string, dialect Dialect, table *Table) string
}
// QuoteFilter filter SQL replace ` to database's own quote character
type QuoteFilter struct {
}
func (s *QuoteFilter) Do(sql string, dialect Dialect, table *Table) string {
dummy := dialect.Quote("")
if len(dummy) != 2 {
return sql
}
prefix, suffix := dummy[0], dummy[1]
raw := []byte(sql)
for i, cnt := 0, 0; i < len(raw); i = i + 1 {
if raw[i] == '`' {
if cnt%2 == 0 {
raw[i] = prefix
} else {
raw[i] = suffix
}
cnt++
}
}
return string(raw)
}
// IdFilter filter SQL replace (id) to primary key column name
type IdFilter struct {
}
type Quoter struct {
dialect Dialect
}
func NewQuoter(dialect Dialect) *Quoter {
return &Quoter{dialect}
}
func (q *Quoter) Quote(content string) string {
return q.dialect.Quote(content)
}
func (i *IdFilter) Do(sql string, dialect Dialect, table *Table) string {
quoter := NewQuoter(dialect)
if table != nil && len(table.PrimaryKeys) == 1 {
sql = strings.Replace(sql, " `(id)` ", " "+quoter.Quote(table.PrimaryKeys[0])+" ", -1)
sql = strings.Replace(sql, " "+quoter.Quote("(id)")+" ", " "+quoter.Quote(table.PrimaryKeys[0])+" ", -1)
return strings.Replace(sql, " (id) ", " "+quoter.Quote(table.PrimaryKeys[0])+" ", -1)
}
return sql
}
// 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, dialect Dialect, table *Table) string {
return convertQuestionMark(sql, s.Prefix, s.Start)
}