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|
package storage
import (
"crypto/rand"
"errors"
"log"
"math/big"
"strings"
)
var ErrNoSuchFile = errors.New("no such file")
type Storage struct {
files map[string]File
}
func NewStorage() *Storage {
return &Storage{
files: make(map[string]File),
}
}
func generateKey(length uint) (string, error) {
key := make([]string, 0, 0)
alphabet := "ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789abcdefghkmnpqrstuvwxyz"
for i := uint(0); i < length; i++ {
n, err := rand.Int(rand.Reader, big.NewInt(int64(len(alphabet))))
if err != nil {
return "", err
}
key = append(key, string(alphabet[n.Int64()]))
}
return strings.Join(key, ""), nil
}
func (s *Storage) Get(key string) (*File, error) {
if file, ok := s.files[key]; ok {
return &file, nil
} else {
return nil, ErrNoSuchFile
}
}
func (s *Storage) Put(file File) (string, error) {
key, err := generateKey(8)
if err != nil {
return "", err
}
s.files[key] = file
return key, nil
}
func (s *Storage) GarbageCollect() {
log.Println("running garbage collection on stored files")
deletedKeys := make([]string, 0)
for key, file := range s.files {
if !file.IsAvailable() {
deletedKeys = append(deletedKeys, key)
}
}
for _, key := range deletedKeys {
log.Println("cleaned up stale file:", key)
delete(s.files, key)
}
}
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