go-clickhouse/ch/chschema/reflect.go

package chschema

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 indirectType(t reflect.Type) reflect.Type {
	if t.Kind() == reflect.Ptr {
		t = t.Elem()
	}
	return t
}

func fieldByIndex(v reflect.Value, index []int) (_ reflect.Value, ok bool) {
	if len(index) == 1 {
		return v.Field(index[0]), true
	}

	for i, idx := range index {
		if i > 0 {
			if v.Kind() == reflect.Ptr {
				if v.IsNil() {
					return v, false
				}
				v = v.Elem()
			}
		}
		v = v.Field(idx)
	}
	return v, true
}

func fieldByIndexAlloc(v reflect.Value, index []int) reflect.Value {
	if len(index) == 1 {
		return v.Field(index[0])
	}

	for i, idx := range index {
		if i > 0 {
			v = indirectNil(v)
		}
		v = v.Field(idx)
	}
	return v
}

func indirectNil(v reflect.Value) reflect.Value {
	if v.Kind() == reflect.Ptr {
		if v.IsNil() {
			v.Set(reflect.New(v.Type().Elem()))
		}
		v = v.Elem()
	}
	return v
}

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)
}