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file_storage.go
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file_storage.go
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// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
// All rights reservefs.
//
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package storage
import (
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"runtime"
"strconv"
"strings"
"sync"
"time"
"camlistore.org/third_party/github.com/syndtr/goleveldb/leveldb/util"
)
var errFileOpen = errors.New("leveldb/storage: file still open")
type fileLock interface {
release() error
}
type fileStorageLock struct {
fs *fileStorage
}
func (lock *fileStorageLock) Release() {
fs := lock.fs
fs.mu.Lock()
defer fs.mu.Unlock()
if fs.slock == lock {
fs.slock = nil
}
return
}
// fileStorage is a file-system backed storage.
type fileStorage struct {
path string
mu sync.Mutex
flock fileLock
slock *fileStorageLock
logw *os.File
buf []byte
// Opened file counter; if open < 0 means closed.
open int
day int
}
// OpenFile returns a new filesytem-backed storage implementation with the given
// path. This also hold a file lock, so any subsequent attempt to open the same
// path will fail.
//
// The storage must be closed after use, by calling Close method.
func OpenFile(path string) (Storage, error) {
if err := os.MkdirAll(path, 0755); err != nil {
return nil, err
}
flock, err := newFileLock(filepath.Join(path, "LOCK"))
if err != nil {
return nil, err
}
defer func() {
if err != nil {
flock.release()
}
}()
rename(filepath.Join(path, "LOG"), filepath.Join(path, "LOG.old"))
logw, err := os.OpenFile(filepath.Join(path, "LOG"), os.O_WRONLY|os.O_CREATE, 0644)
if err != nil {
return nil, err
}
fs := &fileStorage{path: path, flock: flock, logw: logw}
runtime.SetFinalizer(fs, (*fileStorage).Close)
return fs, nil
}
func (fs *fileStorage) Lock() (util.Releaser, error) {
fs.mu.Lock()
defer fs.mu.Unlock()
if fs.open < 0 {
return nil, ErrClosed
}
if fs.slock != nil {
return nil, ErrLocked
}
fs.slock = &fileStorageLock{fs: fs}
return fs.slock, nil
}
func itoa(buf []byte, i int, wid int) []byte {
var u uint = uint(i)
if u == 0 && wid <= 1 {
return append(buf, '0')
}
// Assemble decimal in reverse order.
var b [32]byte
bp := len(b)
for ; u > 0 || wid > 0; u /= 10 {
bp--
wid--
b[bp] = byte(u%10) + '0'
}
return append(buf, b[bp:]...)
}
func (fs *fileStorage) printDay(t time.Time) {
if fs.day == t.Day() {
return
}
fs.day = t.Day()
fs.logw.Write([]byte("=============== " + t.Format("Jan 2, 2006 (MST)") + " ===============\n"))
}
func (fs *fileStorage) doLog(t time.Time, str string) {
fs.printDay(t)
hour, min, sec := t.Clock()
msec := t.Nanosecond() / 1e3
// time
fs.buf = itoa(fs.buf[:0], hour, 2)
fs.buf = append(fs.buf, ':')
fs.buf = itoa(fs.buf, min, 2)
fs.buf = append(fs.buf, ':')
fs.buf = itoa(fs.buf, sec, 2)
fs.buf = append(fs.buf, '.')
fs.buf = itoa(fs.buf, msec, 6)
fs.buf = append(fs.buf, ' ')
// write
fs.buf = append(fs.buf, []byte(str)...)
fs.buf = append(fs.buf, '\n')
fs.logw.Write(fs.buf)
}
func (fs *fileStorage) Log(str string) {
t := time.Now()
fs.mu.Lock()
defer fs.mu.Unlock()
if fs.open < 0 {
return
}
fs.doLog(t, str)
}
func (fs *fileStorage) log(str string) {
fs.doLog(time.Now(), str)
}
func (fs *fileStorage) GetFile(num uint64, t FileType) File {
return &file{fs: fs, num: num, t: t}
}
func (fs *fileStorage) GetFiles(t FileType) (ff []File, err error) {
fs.mu.Lock()
defer fs.mu.Unlock()
if fs.open < 0 {
return nil, ErrClosed
}
dir, err := os.Open(fs.path)
if err != nil {
return
}
fnn, err := dir.Readdirnames(0)
// Close the dir first before checking for Readdirnames error.
if err := dir.Close(); err != nil {
fs.log(fmt.Sprintf("close dir: %v", err))
}
if err != nil {
return
}
f := &file{fs: fs}
for _, fn := range fnn {
if f.parse(fn) && (f.t&t) != 0 {
ff = append(ff, f)
f = &file{fs: fs}
}
}
return
}
func (fs *fileStorage) GetManifest() (f File, err error) {
fs.mu.Lock()
defer fs.mu.Unlock()
if fs.open < 0 {
return nil, ErrClosed
}
dir, err := os.Open(fs.path)
if err != nil {
return
}
fnn, err := dir.Readdirnames(0)
// Close the dir first before checking for Readdirnames error.
if err := dir.Close(); err != nil {
fs.log(fmt.Sprintf("close dir: %v", err))
}
if err != nil {
return
}
// Find latest CURRENT file.
var rem []string
var pend bool
var cerr error
for _, fn := range fnn {
if strings.HasPrefix(fn, "CURRENT") {
pend1 := len(fn) > 7
// Make sure it is valid name for a CURRENT file, otherwise skip it.
if pend1 {
if fn[7] != '.' || len(fn) < 9 {
fs.log(fmt.Sprintf("skipping %s: invalid file name", fn))
continue
}
if _, e1 := strconv.ParseUint(fn[7:], 10, 0); e1 != nil {
fs.log(fmt.Sprintf("skipping %s: invalid file num: %v", fn, e1))
continue
}
}
path := filepath.Join(fs.path, fn)
r, e1 := os.OpenFile(path, os.O_RDONLY, 0)
if e1 != nil {
return nil, e1
}
b, e1 := ioutil.ReadAll(r)
if e1 != nil {
r.Close()
return nil, e1
}
f1 := &file{fs: fs}
if len(b) < 1 || b[len(b)-1] != '\n' || !f1.parse(string(b[:len(b)-1])) {
fs.log(fmt.Sprintf("skipping %s: corrupted or incomplete", fn))
if pend1 {
rem = append(rem, fn)
}
if !pend1 || cerr == nil {
cerr = fmt.Errorf("leveldb/storage: corrupted or incomplete %s file", fn)
}
} else if f != nil && f1.Num() < f.Num() {
fs.log(fmt.Sprintf("skipping %s: obsolete", fn))
if pend1 {
rem = append(rem, fn)
}
} else {
f = f1
pend = pend1
}
if err := r.Close(); err != nil {
fs.log(fmt.Sprintf("close %s: %v", fn, err))
}
}
}
// Don't remove any files if there is no valid CURRENT file.
if f == nil {
if cerr != nil {
err = cerr
} else {
err = os.ErrNotExist
}
return
}
// Rename pending CURRENT file to an effective CURRENT.
if pend {
path := fmt.Sprintf("%s.%d", filepath.Join(fs.path, "CURRENT"), f.Num())
if err := rename(path, filepath.Join(fs.path, "CURRENT")); err != nil {
fs.log(fmt.Sprintf("CURRENT.%d -> CURRENT: %v", f.Num(), err))
}
}
// Remove obsolete or incomplete pending CURRENT files.
for _, fn := range rem {
path := filepath.Join(fs.path, fn)
if err := os.Remove(path); err != nil {
fs.log(fmt.Sprintf("remove %s: %v", fn, err))
}
}
return
}
func (fs *fileStorage) SetManifest(f File) (err error) {
fs.mu.Lock()
defer fs.mu.Unlock()
if fs.open < 0 {
return ErrClosed
}
f2, ok := f.(*file)
if !ok || f2.t != TypeManifest {
return ErrInvalidFile
}
defer func() {
if err != nil {
fs.log(fmt.Sprintf("CURRENT: %v", err))
}
}()
path := fmt.Sprintf("%s.%d", filepath.Join(fs.path, "CURRENT"), f2.Num())
w, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return err
}
_, err = fmt.Fprintln(w, f2.name())
// Close the file first.
if err := w.Close(); err != nil {
fs.log(fmt.Sprintf("close CURRENT.%d: %v", f2.num, err))
}
if err != nil {
return err
}
return rename(path, filepath.Join(fs.path, "CURRENT"))
}
func (fs *fileStorage) Close() error {
fs.mu.Lock()
defer fs.mu.Unlock()
if fs.open < 0 {
return ErrClosed
}
// Clear the finalizer.
runtime.SetFinalizer(fs, nil)
if fs.open > 0 {
fs.log(fmt.Sprintf("refuse to close, %d files still open", fs.open))
return fmt.Errorf("leveldb/storage: cannot close, %d files still open", fs.open)
}
fs.open = -1
e1 := fs.logw.Close()
err := fs.flock.release()
if err == nil {
err = e1
}
return err
}
type fileWrap struct {
*os.File
f *file
}
func (fw fileWrap) Sync() error {
if err := fw.File.Sync(); err != nil {
return err
}
if fw.f.Type() == TypeManifest {
// Also sync parent directory if file type is manifest.
// See: https://code.google.com/p/leveldb/issues/detail?id=190.
if err := syncDir(fw.f.fs.path); err != nil {
return err
}
}
return nil
}
func (fw fileWrap) Close() error {
f := fw.f
f.fs.mu.Lock()
defer f.fs.mu.Unlock()
if !f.open {
return ErrClosed
}
f.open = false
f.fs.open--
err := fw.File.Close()
if err != nil {
f.fs.log(fmt.Sprintf("close %s.%d: %v", f.Type(), f.Num(), err))
}
return err
}
type file struct {
fs *fileStorage
num uint64
t FileType
open bool
}
func (f *file) Open() (Reader, error) {
f.fs.mu.Lock()
defer f.fs.mu.Unlock()
if f.fs.open < 0 {
return nil, ErrClosed
}
if f.open {
return nil, errFileOpen
}
of, err := os.OpenFile(f.path(), os.O_RDONLY, 0)
if err != nil {
if f.hasOldName() && os.IsNotExist(err) {
of, err = os.OpenFile(f.oldPath(), os.O_RDONLY, 0)
if err == nil {
goto ok
}
}
return nil, err
}
ok:
f.open = true
f.fs.open++
return fileWrap{of, f}, nil
}
func (f *file) Create() (Writer, error) {
f.fs.mu.Lock()
defer f.fs.mu.Unlock()
if f.fs.open < 0 {
return nil, ErrClosed
}
if f.open {
return nil, errFileOpen
}
of, err := os.OpenFile(f.path(), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return nil, err
}
f.open = true
f.fs.open++
return fileWrap{of, f}, nil
}
func (f *file) Replace(newfile File) error {
f.fs.mu.Lock()
defer f.fs.mu.Unlock()
if f.fs.open < 0 {
return ErrClosed
}
newfile2, ok := newfile.(*file)
if !ok {
return ErrInvalidFile
}
if f.open || newfile2.open {
return errFileOpen
}
return rename(newfile2.path(), f.path())
}
func (f *file) Type() FileType {
return f.t
}
func (f *file) Num() uint64 {
return f.num
}
func (f *file) Remove() error {
f.fs.mu.Lock()
defer f.fs.mu.Unlock()
if f.fs.open < 0 {
return ErrClosed
}
if f.open {
return errFileOpen
}
err := os.Remove(f.path())
if err != nil {
f.fs.log(fmt.Sprintf("remove %s.%d: %v", f.Type(), f.Num(), err))
}
// Also try remove file with old name, just in case.
if f.hasOldName() {
if e1 := os.Remove(f.oldPath()); !os.IsNotExist(e1) {
f.fs.log(fmt.Sprintf("remove %s.%d: %v (old name)", f.Type(), f.Num(), err))
err = e1
}
}
return err
}
func (f *file) hasOldName() bool {
return f.t == TypeTable
}
func (f *file) oldName() string {
switch f.t {
case TypeTable:
return fmt.Sprintf("%06d.sst", f.num)
}
return f.name()
}
func (f *file) oldPath() string {
return filepath.Join(f.fs.path, f.oldName())
}
func (f *file) name() string {
switch f.t {
case TypeManifest:
return fmt.Sprintf("MANIFEST-%06d", f.num)
case TypeJournal:
return fmt.Sprintf("%06d.log", f.num)
case TypeTable:
return fmt.Sprintf("%06d.ldb", f.num)
case TypeTemp:
return fmt.Sprintf("%06d.tmp", f.num)
default:
panic("invalid file type")
}
}
func (f *file) path() string {
return filepath.Join(f.fs.path, f.name())
}
func (f *file) parse(name string) bool {
var num uint64
var tail string
_, err := fmt.Sscanf(name, "%d.%s", &num, &tail)
if err == nil {
switch tail {
case "log":
f.t = TypeJournal
case "ldb", "sst":
f.t = TypeTable
case "tmp":
f.t = TypeTemp
default:
return false
}
f.num = num
return true
}
n, _ := fmt.Sscanf(name, "MANIFEST-%d%s", &num, &tail)
if n == 1 {
f.t = TypeManifest
f.num = num
return true
}
return false
}