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golang readonly

Restu Wahyu Saputra answered on April 19, 2023 Popularity 2/10 Helpfulness 1/10

answer golang readonly

golang readonly

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package main

import (
	"fmt"
	"reflect"
	"strings"
	"sync"
	"sync/atomic"
)

type structReadonly struct {
	isError       error
	isReadonly    bool
	fields        []string
	mergeFields   string
	previousValue map[string]interface{}
	nextValue     map[string]interface{}
}

type interfaceReadonly interface {
	PreviousValue(src interface{}, fields []string) *structReadonly
	NextValue(src interface{}) (bool, error)
}

func ReadonlyForMap() interfaceReadonly {
	return &structReadonly{}
}

func (h *structReadonly) PreviousValue(src interface{}, fields []string) *structReadonly {
	var (
		newSrcValueMap map[string]interface{} = make(map[string]interface{})
	)

	if ok := reflect.ValueOf(src).CanConvert(reflect.TypeOf(newSrcValueMap)); !ok {
		h.isError = fmt.Errorf("src must be a map type not %s", reflect.ValueOf(src).Kind().String())
		h.isReadonly = false
	}

	srcValueMaps, err := InterfaceToMap(src)
	if err != nil {
		h.isError = err
		h.isReadonly = false
	}

	h.fields = fields
	h.previousValue = srcValueMaps

	return h
}

func (h *structReadonly) NextValue(src interface{}) (bool, error) {
	var (
		mutex           *sync.RWMutex          = &sync.RWMutex{}
		safeValueSrcKey *atomic.Value          = &atomic.Value{}
		maps            map[string]interface{} = make(map[string]interface{})
		mergeFields     string                 = ""
	)

	if ok := reflect.ValueOf(src).CanConvert(reflect.TypeOf(maps)); !ok {
		return false, fmt.Errorf("src must be a map type not %s", reflect.ValueOf(src).Kind().String())
	}

	srcValueMaps, err := InterfaceToMap(src)
	if err != nil {
		return false, err
	}

	h.nextValue = srcValueMaps

	for k, v := range h.previousValue {
		safeValueSrcKey.Store(k)

		for i := 0; i < len(h.fields); i++ {
			if h.previousValue[h.fields[i]] == v {
				if h.nextValue[h.fields[i]] != h.previousValue[h.fields[i]] {
					mutex.Lock()
					mergeFields += safeValueSrcKey.Load().(string) + "|"
					mutex.Unlock()
					break
				}
				delete(h.previousValue, k)
				delete(h.nextValue, k)
			}
		}
	}

	if mergeFields != "" {
		cutSuffix, _ := strings.CutSuffix(mergeFields, "|")
		return false, fmt.Errorf("Cannot assign to %s because it is a read-only property", cutSuffix)
	}

	defer func() {
		mergeFields = ""
		h.previousValue = nil
		h.nextValue = nil
	}()

	return true, nil
}

type Person struct {
	Name     string `json:"name"`
	Age      int    `json:"age"`
	Address  string `json:"address"`
	City     string `json:"city"`
	Country  string `json:"country"`
	State    string `json:"state"`
	PostCode string `json:"postcode"`
}

func main() {
	body := make(map[string]interface{})
	body["name"] = "john doe"
	body["age"] = 23
	body["address"] = "Jl.nusantara rt.01/rw.12"
	body["city"] = "depok"
	body["country"] = "indonesia"
	body["state"] = "jawa barat"
	body["postcode"] = "14356"

	ro := ReadonlyForMap().PreviousValue(body, []string{"name", "age"})
	body["name"] = "samsul"
	body["age"] = 21
	body["address"] = "Jl.surdirman raya"

	ok, err := ro.NextValue(body)
	if err != nil {
		fmt.Println(err.Error()) //  Cannot assign to name|age because it is a read-only property
	}

	fmt.Println(ok)
}

Popularity 2/10 Helpfulness 1/10 Language go

Source: Grepper

Tags: go readonly

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Contributed on Apr 19 2023

Restu Wahyu Saputra

0 Answers Avg Quality 2/10

golang readonly

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