gotosocial/vendor/github.com/uptrace/bun/util.go
tobi 2dc9fc1626
Pg to bun (#148)
* start moving to bun

* changing more stuff

* more

* and yet more

* tests passing

* seems stable now

* more big changes

* small fix

* little fixes
2021-08-25 15:34:33 +02:00

114 lines
2.1 KiB
Go

package bun
import "reflect"
func indirect(v reflect.Value) reflect.Value {
switch v.Kind() {
case reflect.Interface:
return indirect(v.Elem())
case reflect.Ptr:
return v.Elem()
default:
return v
}
}
func walk(v reflect.Value, index []int, fn func(reflect.Value)) {
v = reflect.Indirect(v)
switch v.Kind() {
case reflect.Slice:
sliceLen := v.Len()
for i := 0; i < sliceLen; i++ {
visitField(v.Index(i), index, fn)
}
default:
visitField(v, index, fn)
}
}
func visitField(v reflect.Value, index []int, fn func(reflect.Value)) {
v = reflect.Indirect(v)
if len(index) > 0 {
v = v.Field(index[0])
if v.Kind() == reflect.Ptr && v.IsNil() {
return
}
walk(v, index[1:], fn)
} else {
fn(v)
}
}
func typeByIndex(t reflect.Type, index []int) reflect.Type {
for _, x := range index {
switch t.Kind() {
case reflect.Ptr:
t = t.Elem()
case reflect.Slice:
t = indirectType(t.Elem())
}
t = t.Field(x).Type
}
return indirectType(t)
}
func indirectType(t reflect.Type) reflect.Type {
if t.Kind() == reflect.Ptr {
t = t.Elem()
}
return t
}
func sliceElemType(v reflect.Value) reflect.Type {
elemType := v.Type().Elem()
if elemType.Kind() == reflect.Interface && v.Len() > 0 {
return indirect(v.Index(0).Elem()).Type()
}
return indirectType(elemType)
}
func makeSliceNextElemFunc(v reflect.Value) func() reflect.Value {
if v.Kind() == reflect.Array {
var pos int
return func() reflect.Value {
v := v.Index(pos)
pos++
return v
}
}
sliceType := v.Type()
elemType := sliceType.Elem()
if elemType.Kind() == reflect.Ptr {
elemType = elemType.Elem()
return func() reflect.Value {
if v.Len() < v.Cap() {
v.Set(v.Slice(0, v.Len()+1))
elem := v.Index(v.Len() - 1)
if elem.IsNil() {
elem.Set(reflect.New(elemType))
}
return elem.Elem()
}
elem := reflect.New(elemType)
v.Set(reflect.Append(v, elem))
return elem.Elem()
}
}
zero := reflect.Zero(elemType)
return func() reflect.Value {
l := v.Len()
c := v.Cap()
if l < c {
v.Set(v.Slice(0, l+1))
return v.Index(l)
}
v.Set(reflect.Append(v, zero))
return v.Index(l)
}
}