peridot/vendor/github.com/jmoiron/sqlx/bind.go

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2022-07-07 20:11:50 +00:00
package sqlx
import (
"bytes"
"database/sql/driver"
"errors"
"reflect"
"strconv"
"strings"
"sync"
"github.com/jmoiron/sqlx/reflectx"
)
// Bindvar types supported by Rebind, BindMap and BindStruct.
const (
UNKNOWN = iota
QUESTION
DOLLAR
NAMED
AT
)
var defaultBinds = map[int][]string{
DOLLAR: []string{"postgres", "pgx", "pq-timeouts", "cloudsqlpostgres", "ql", "nrpostgres", "cockroach"},
QUESTION: []string{"mysql", "sqlite3", "nrmysql", "nrsqlite3"},
NAMED: []string{"oci8", "ora", "goracle", "godror"},
AT: []string{"sqlserver"},
}
var binds sync.Map
func init() {
for bind, drivers := range defaultBinds {
for _, driver := range drivers {
BindDriver(driver, bind)
}
}
}
// BindType returns the bindtype for a given database given a drivername.
func BindType(driverName string) int {
itype, ok := binds.Load(driverName)
if !ok {
return UNKNOWN
}
return itype.(int)
}
// BindDriver sets the BindType for driverName to bindType.
func BindDriver(driverName string, bindType int) {
binds.Store(driverName, bindType)
}
// FIXME: this should be able to be tolerant of escaped ?'s in queries without
// losing much speed, and should be to avoid confusion.
// Rebind a query from the default bindtype (QUESTION) to the target bindtype.
func Rebind(bindType int, query string) string {
switch bindType {
case QUESTION, UNKNOWN:
return query
}
// Add space enough for 10 params before we have to allocate
rqb := make([]byte, 0, len(query)+10)
var i, j int
for i = strings.Index(query, "?"); i != -1; i = strings.Index(query, "?") {
rqb = append(rqb, query[:i]...)
switch bindType {
case DOLLAR:
rqb = append(rqb, '$')
case NAMED:
rqb = append(rqb, ':', 'a', 'r', 'g')
case AT:
rqb = append(rqb, '@', 'p')
}
j++
rqb = strconv.AppendInt(rqb, int64(j), 10)
query = query[i+1:]
}
return string(append(rqb, query...))
}
// Experimental implementation of Rebind which uses a bytes.Buffer. The code is
// much simpler and should be more resistant to odd unicode, but it is twice as
// slow. Kept here for benchmarking purposes and to possibly replace Rebind if
// problems arise with its somewhat naive handling of unicode.
func rebindBuff(bindType int, query string) string {
if bindType != DOLLAR {
return query
}
b := make([]byte, 0, len(query))
rqb := bytes.NewBuffer(b)
j := 1
for _, r := range query {
if r == '?' {
rqb.WriteRune('$')
rqb.WriteString(strconv.Itoa(j))
j++
} else {
rqb.WriteRune(r)
}
}
return rqb.String()
}
func asSliceForIn(i interface{}) (v reflect.Value, ok bool) {
if i == nil {
return reflect.Value{}, false
}
v = reflect.ValueOf(i)
t := reflectx.Deref(v.Type())
// Only expand slices
if t.Kind() != reflect.Slice {
return reflect.Value{}, false
}
// []byte is a driver.Value type so it should not be expanded
if t == reflect.TypeOf([]byte{}) {
return reflect.Value{}, false
}
return v, true
}
// In expands slice values in args, returning the modified query string
// and a new arg list that can be executed by a database. The `query` should
// use the `?` bindVar. The return value uses the `?` bindVar.
func In(query string, args ...interface{}) (string, []interface{}, error) {
// argMeta stores reflect.Value and length for slices and
// the value itself for non-slice arguments
type argMeta struct {
v reflect.Value
i interface{}
length int
}
var flatArgsCount int
var anySlices bool
var stackMeta [32]argMeta
var meta []argMeta
if len(args) <= len(stackMeta) {
meta = stackMeta[:len(args)]
} else {
meta = make([]argMeta, len(args))
}
for i, arg := range args {
if a, ok := arg.(driver.Valuer); ok {
var err error
arg, err = a.Value()
if err != nil {
return "", nil, err
}
}
if v, ok := asSliceForIn(arg); ok {
meta[i].length = v.Len()
meta[i].v = v
anySlices = true
flatArgsCount += meta[i].length
if meta[i].length == 0 {
return "", nil, errors.New("empty slice passed to 'in' query")
}
} else {
meta[i].i = arg
flatArgsCount++
}
}
// don't do any parsing if there aren't any slices; note that this means
// some errors that we might have caught below will not be returned.
if !anySlices {
return query, args, nil
}
newArgs := make([]interface{}, 0, flatArgsCount)
var buf strings.Builder
buf.Grow(len(query) + len(", ?")*flatArgsCount)
var arg, offset int
for i := strings.IndexByte(query[offset:], '?'); i != -1; i = strings.IndexByte(query[offset:], '?') {
if arg >= len(meta) {
// if an argument wasn't passed, lets return an error; this is
// not actually how database/sql Exec/Query works, but since we are
// creating an argument list programmatically, we want to be able
// to catch these programmer errors earlier.
return "", nil, errors.New("number of bindVars exceeds arguments")
}
argMeta := meta[arg]
arg++
// not a slice, continue.
// our questionmark will either be written before the next expansion
// of a slice or after the loop when writing the rest of the query
if argMeta.length == 0 {
offset = offset + i + 1
newArgs = append(newArgs, argMeta.i)
continue
}
// write everything up to and including our ? character
buf.WriteString(query[:offset+i+1])
for si := 1; si < argMeta.length; si++ {
buf.WriteString(", ?")
}
newArgs = appendReflectSlice(newArgs, argMeta.v, argMeta.length)
// slice the query and reset the offset. this avoids some bookkeeping for
// the write after the loop
query = query[offset+i+1:]
offset = 0
}
buf.WriteString(query)
if arg < len(meta) {
return "", nil, errors.New("number of bindVars less than number arguments")
}
return buf.String(), newArgs, nil
}
func appendReflectSlice(args []interface{}, v reflect.Value, vlen int) []interface{} {
switch val := v.Interface().(type) {
case []interface{}:
args = append(args, val...)
case []int:
for i := range val {
args = append(args, val[i])
}
case []string:
for i := range val {
args = append(args, val[i])
}
default:
for si := 0; si < vlen; si++ {
args = append(args, v.Index(si).Interface())
}
}
return args
}