inmemory.go

package dht

import (
	"errors"
	"sync"
)

//go:generate mockgen -destination mock_kv_test.go -package nameserver . kv
type kv interface {
	get(string) ([]byte, error)
	set(string, []byte) error
}

var (
	errKeyNotFound = errors.New("key not found")
	errKeyExists   = errors.New("key exists")
)

type inmemory struct {
	mu     sync.RWMutex
	values map[string][]byte
}

// interface compliance
var _ kv = (*inmemory)(nil)

func newInmemoryStore() kv {
	return &inmemory{
		mu:     sync.RWMutex{},
		values: make(map[string][]byte),
	}
}

func (k *inmemory) get(key string) ([]byte, error) {
	k.mu.RLock()
	defer k.mu.RUnlock()

	value, ok := k.values[key]
	if !ok {
		return nil, errKeyNotFound
	}

	return value, nil
}

func (k *inmemory) set(key string, value []byte) error {
	if value == nil {
		return errors.New("nil value")
	}

	k.mu.Lock()
	defer k.mu.Unlock()

	_, ok := k.values[key]
	if ok {
		return errKeyExists
	}

	k.values[key] = value
	return nil
}