Lightweight and fast SQL builder for Go language
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// Copyright 2018 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 builder
import (
sql2 "database/sql"
"fmt"
"reflect"
"strings"
"time"
)
func condToSQL(cond Cond) (string, []interface{}, error) {
if cond == nil || !cond.IsValid() {
return "", nil, nil
}
w := NewWriter()
if err := cond.WriteTo(w); err != nil {
return "", nil, err
}
return w.String(), w.args, nil
}
func condToBoundSQL(cond Cond) (string, error) {
if cond == nil || !cond.IsValid() {
return "", nil
}
w := NewWriter()
if err := cond.WriteTo(w); err != nil {
return "", err
}
return ConvertToBoundSQL(w.String(), w.args)
}
// ToSQL convert a builder or conditions to SQL and args
func ToSQL(cond interface{}) (string, []interface{}, error) {
switch cond.(type) {
case Cond:
return condToSQL(cond.(Cond))
case *Builder:
return cond.(*Builder).ToSQL()
}
return "", nil, ErrNotSupportType
}
// ToBoundSQL convert a builder or conditions to parameters bound SQL
func ToBoundSQL(cond interface{}) (string, error) {
switch cond.(type) {
case Cond:
return condToBoundSQL(cond.(Cond))
case *Builder:
return cond.(*Builder).ToBoundSQL()
}
return "", ErrNotSupportType
}
func noSQLQuoteNeeded(a interface{}) bool {
if a == nil {
return false
}
switch a.(type) {
case int, int8, int16, int32, int64:
return true
case uint, uint8, uint16, uint32, uint64:
return true
case float32, float64:
return true
case bool:
return true
case string:
return false
case time.Time, *time.Time:
return false
}
t := reflect.TypeOf(a)
switch t.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return true
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return true
case reflect.Float32, reflect.Float64:
return true
case reflect.Bool:
return true
case reflect.String:
return false
}
return false
}
// ConvertToBoundSQL will convert SQL and args to a bound SQL
func ConvertToBoundSQL(sql string, args []interface{}) (string, error) {
buf := strings.Builder{}
var i, j, start int
for ; i < len(sql); i++ {
if sql[i] == '?' {
_, err := buf.WriteString(sql[start:i])
if err != nil {
return "", err
}
start = i + 1
if len(args) == j {
return "", ErrNeedMoreArguments
}
arg := args[j]
if namedArg, ok := arg.(sql2.NamedArg); ok {
arg = namedArg.Value
}
if noSQLQuoteNeeded(arg) {
_, err = fmt.Fprint(&buf, arg)
} else {
// replace ' -> '' (standard replacement) to avoid critical SQL injection,
// NOTICE: may allow some injection like % (or _) in LIKE query
_, err = fmt.Fprintf(&buf, "'%v'", strings.Replace(fmt.Sprintf("%v", arg), "'",
"''", -1))
}
if err != nil {
return "", err
}
j = j + 1
}
}
_, err := buf.WriteString(sql[start:])
if err != nil {
return "", err
}
return buf.String(), nil
}
// ConvertPlaceholder replaces the place holder ? to $1, $2 ... or :1, :2 ... according prefix
func ConvertPlaceholder(sql, prefix string) (string, error) {
buf := strings.Builder{}
var i, j, start int
var ready = true
for ; i < len(sql); i++ {
if sql[i] == '\'' && i > 0 && sql[i-1] != '\\' {
ready = !ready
}
if ready && sql[i] == '?' {
if _, err := buf.WriteString(sql[start:i]); err != nil {
return "", err
}
start = i + 1
j = j + 1
if _, err := buf.WriteString(fmt.Sprintf("%v%d", prefix, j)); err != nil {
return "", err
}
}
}
if _, err := buf.WriteString(sql[start:]); err != nil {
return "", err
}
return buf.String(), nil
}