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- package util
- import (
- "errors"
- "io/ioutil"
- "os"
- "path/filepath"
- "strings"
- "sync"
- )
- var (
- errInvalidKey = errors.New("invalid key")
- errNoSuchKey = errors.New("no such key")
- )
- type Database struct {
- cache map[string][]byte
- basedir string
- m sync.RWMutex
- }
- func NewDatabse(basedir string) (db *Database, err error) {
- err = os.Mkdir(basedir, 0755)
- if err != nil && !os.IsExist(err) {
- return
- }
- return &Database{
- cache: make(map[string][]byte),
- basedir: basedir,
- }, nil
- }
- func (db *Database) Set(key string, val []byte) (err error) {
- if len(key) < 1 || strings.ContainsRune(key, os.PathSeparator) {
- return errInvalidKey
- }
- err = ioutil.WriteFile(filepath.Join(db.basedir, key), val, 0644)
- if err != nil {
- return
- }
- db.m.Lock()
- db.cache[key] = val
- db.m.Unlock()
- return
- }
- func (db *Database) Get(key string) (val []byte, err error) {
- if len(key) < 1 || strings.ContainsRune(key, os.PathSeparator) {
- return nil, errInvalidKey
- }
- db.m.RLock()
- data, ok := db.cache[key]
- db.m.RUnlock()
- if !ok {
- data, err = ioutil.ReadFile(filepath.Join(db.basedir, key))
- if err != nil {
- err = errNoSuchKey
- return nil, err
- }
- db.m.Lock()
- db.cache[key] = data
- db.m.Unlock()
- }
- val = make([]byte, len(data))
- copy(val, data)
- return
- }
- func (db *Database) Remove(key string) {
- if len(key) < 1 || strings.ContainsRune(key, os.PathSeparator) {
- return
- }
- os.Remove(filepath.Join(db.basedir, key))
- db.m.Lock()
- delete(db.cache, key)
- db.m.Unlock()
- return
- }
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