package db import ( "fmt" "io/ioutil" "net/url" "os" "path/filepath" "sort" "sync" "github.com/pkg/errors" cmn "github.com/tendermint/tendermint/libs/common" tmerrors "github.com/tendermint/tendermint/libs/errors" ) const ( keyPerm = os.FileMode(0600) dirPerm = os.FileMode(0700) ) func init() { registerDBCreator(FSDBBackend, func(name string, dir string) (DB, error) { dbPath := filepath.Join(dir, name+".db") return NewFSDB(dbPath), nil }, false) } var _ DB = (*FSDB)(nil) // It's slow. type FSDB struct { mtx sync.Mutex dir string } func NewFSDB(dir string) *FSDB { err := os.MkdirAll(dir, dirPerm) if err != nil { panic(errors.Wrap(err, "Creating FSDB dir "+dir)) } database := &FSDB{ dir: dir, } return database } func (db *FSDB) Get(key []byte) []byte { db.mtx.Lock() defer db.mtx.Unlock() key = escapeKey(key) path := db.nameToPath(key) value, err := read(path) if os.IsNotExist(err) { return nil } else if err != nil { panic(errors.Wrapf(err, "Getting key %s (0x%X)", string(key), key)) } return value } func (db *FSDB) Has(key []byte) bool { db.mtx.Lock() defer db.mtx.Unlock() key = escapeKey(key) path := db.nameToPath(key) return cmn.FileExists(path) } func (db *FSDB) Set(key []byte, value []byte) { db.mtx.Lock() defer db.mtx.Unlock() db.SetNoLock(key, value) } func (db *FSDB) SetSync(key []byte, value []byte) { db.mtx.Lock() defer db.mtx.Unlock() db.SetNoLock(key, value) } // NOTE: Implements atomicSetDeleter. func (db *FSDB) SetNoLock(key []byte, value []byte) { key = escapeKey(key) value = nonNilBytes(value) path := db.nameToPath(key) err := write(path, value) if err != nil { panic(errors.Wrapf(err, "Setting key %s (0x%X)", string(key), key)) } } func (db *FSDB) Delete(key []byte) { db.mtx.Lock() defer db.mtx.Unlock() db.DeleteNoLock(key) } func (db *FSDB) DeleteSync(key []byte) { db.mtx.Lock() defer db.mtx.Unlock() db.DeleteNoLock(key) } // NOTE: Implements atomicSetDeleter. func (db *FSDB) DeleteNoLock(key []byte) { key = escapeKey(key) path := db.nameToPath(key) err := remove(path) if os.IsNotExist(err) { return } else if err != nil { panic(errors.Wrapf(err, "Removing key %s (0x%X)", string(key), key)) } } func (db *FSDB) Close() { // Nothing to do. } func (db *FSDB) Print() { db.mtx.Lock() defer db.mtx.Unlock() panic("FSDB.Print not yet implemented") } func (db *FSDB) Stats() map[string]string { db.mtx.Lock() defer db.mtx.Unlock() panic("FSDB.Stats not yet implemented") } func (db *FSDB) NewBatch() Batch { db.mtx.Lock() defer db.mtx.Unlock() // Not sure we would ever want to try... // It doesn't seem easy for general filesystems. panic("FSDB.NewBatch not yet implemented") } func (db *FSDB) Mutex() *sync.Mutex { return &(db.mtx) } func (db *FSDB) Iterator(start, end []byte) Iterator { return db.MakeIterator(start, end, false) } func (db *FSDB) MakeIterator(start, end []byte, isReversed bool) Iterator { db.mtx.Lock() defer db.mtx.Unlock() // We need a copy of all of the keys. // Not the best, but probably not a bottleneck depending. keys, err := list(db.dir, start, end, isReversed) if err != nil { panic(errors.Wrapf(err, "Listing keys in %s", db.dir)) } if isReversed { sort.Sort(sort.Reverse(sort.StringSlice(keys))) } else { sort.Strings(keys) } return newMemDBIterator(db, keys, start, end) } func (db *FSDB) ReverseIterator(start, end []byte) Iterator { return db.MakeIterator(start, end, true) } func (db *FSDB) nameToPath(name []byte) string { n := url.PathEscape(string(name)) return filepath.Join(db.dir, n) } // Read some bytes to a file. // CONTRACT: returns os errors directly without wrapping. func read(path string) ([]byte, error) { f, err := os.Open(path) if err != nil { return nil, err } defer f.Close() d, err := ioutil.ReadAll(f) if err != nil { return nil, err } return d, nil } // Write some bytes from a file. // CONTRACT: returns os errors directly without wrapping. func write(path string, d []byte) error { f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, keyPerm) if err != nil { return err } defer f.Close() fInfo, err := f.Stat() if err != nil { return err } if fInfo.Mode() != keyPerm { return tmerrors.NewErrPermissionsChanged(f.Name(), keyPerm, fInfo.Mode()) } _, err = f.Write(d) if err != nil { return err } err = f.Sync() return err } // Remove a file. // CONTRACT: returns os errors directly without wrapping. func remove(path string) error { return os.Remove(path) } // List keys in a directory, stripping of escape sequences and dir portions. // CONTRACT: returns os errors directly without wrapping. func list(dirPath string, start, end []byte, isReversed bool) ([]string, error) { dir, err := os.Open(dirPath) if err != nil { return nil, err } defer dir.Close() names, err := dir.Readdirnames(0) if err != nil { return nil, err } var keys []string for _, name := range names { n, err := url.PathUnescape(name) if err != nil { return nil, fmt.Errorf("Failed to unescape %s while listing", name) } key := unescapeKey([]byte(n)) if IsKeyInDomain(key, start, end, isReversed) { keys = append(keys, string(key)) } } return keys, nil } // To support empty or nil keys, while the file system doesn't allow empty // filenames. func escapeKey(key []byte) []byte { return []byte("k_" + string(key)) } func unescapeKey(escKey []byte) []byte { if len(escKey) < 2 { panic(fmt.Sprintf("Invalid esc key: %x", escKey)) } if string(escKey[:2]) != "k_" { panic(fmt.Sprintf("Invalid esc key: %x", escKey)) } return escKey[2:] }