82 lines
1.3 KiB
Go
82 lines
1.3 KiB
Go
package internal
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import (
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"reflect"
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)
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func MakeSliceNextElemFunc(v reflect.Value) func() reflect.Value {
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if v.Kind() == reflect.Array {
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var pos int
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return func() reflect.Value {
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v := v.Index(pos)
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pos++
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return v
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}
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}
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elemType := v.Type().Elem()
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if elemType.Kind() == reflect.Ptr {
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elemType = elemType.Elem()
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return func() reflect.Value {
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if v.Len() < v.Cap() {
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v.Set(v.Slice(0, v.Len()+1))
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elem := v.Index(v.Len() - 1)
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if elem.IsNil() {
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elem.Set(reflect.New(elemType))
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}
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return elem
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}
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elem := reflect.New(elemType)
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v.Set(reflect.Append(v, elem))
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return elem
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}
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}
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zero := reflect.Zero(elemType)
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return func() reflect.Value {
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if v.Len() < v.Cap() {
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v.Set(v.Slice(0, v.Len()+1))
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return v.Index(v.Len() - 1)
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}
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v.Set(reflect.Append(v, zero))
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return v.Index(v.Len() - 1)
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}
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}
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func Unwrap(err error) error {
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u, ok := err.(interface {
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Unwrap() error
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})
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if !ok {
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return nil
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}
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return u.Unwrap()
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}
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func FieldByIndexAlloc(v reflect.Value, index []int) reflect.Value {
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if len(index) == 1 {
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return v.Field(index[0])
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}
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for i, idx := range index {
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if i > 0 {
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v = indirectNil(v)
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}
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v = v.Field(idx)
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}
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return v
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}
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func indirectNil(v reflect.Value) reflect.Value {
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if v.Kind() == reflect.Ptr {
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if v.IsNil() {
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v.Set(reflect.New(v.Type().Elem()))
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}
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v = v.Elem()
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}
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return v
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}
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