func (o *Options) acidFiler(db *DB, f lldb.Filer) (r lldb.Filer, err error) {
switch o._ACID {
default:
panic("internal error")
case _ACIDTransactions:
if r, err = lldb.NewRollbackFiler(
f,
func(sz int64) error {
return f.Truncate(sz)
},
f,
); err != nil {
return nil, err
}
return r, nil
case _ACIDFull:
if r, err = lldb.NewACIDFiler(f, o.wal); err != nil {
return nil, err
}
db.acidState = stIdle
db.gracePeriod = o._GracePeriod
if o._GracePeriod == 0 {
panic("internal error")
}
return r, nil
}
}
func (o *Options) acidFiler(db *DB, f lldb.Filer) (r lldb.Filer, err error) {
switch o.ACID {
default:
panic("internal error")
case ACIDNone:
r = f
case ACIDTransactions:
var rf *lldb.RollbackFiler
if rf, err = lldb.NewRollbackFiler(
f,
func(sz int64) error {
return f.Truncate(sz)
},
f,
); err != nil {
return
}
db.xact = true
r = rf
case ACIDFull:
if r, err = lldb.NewACIDFiler(f, o.wal); err != nil {
return
}
db.acidState = stIdle
db.gracePeriod = o.GracePeriod
db.xact = true
if o.GracePeriod == 0 {
db.acidState = stDisabled
break
}
// Ensure GOMAXPROCS > 1, required for ACID FSM
if n := runtime.GOMAXPROCS(0); n > 1 {
return
}
runtime.GOMAXPROCS(2)
}
return
}
func newFileFromOSFile(f lldb.OSFile) (fi *file, err error) {
nm := lockName(f.Name())
lck, err := lock.Lock(nm)
if err != nil {
if lck != nil {
lck.Close()
}
return nil, err
}
close := true
defer func() {
if close && lck != nil {
lck.Close()
}
}()
var w *os.File
closew := false
wn := walName(f.Name())
w, err = os.OpenFile(wn, os.O_CREATE|os.O_EXCL|os.O_RDWR, 0666)
closew = true
defer func() {
if closew {
nm := w.Name()
w.Close()
os.Remove(nm)
w = nil
}
}()
if err != nil {
if !os.IsExist(err) {
return nil, err
}
closew = false
w, err = os.OpenFile(wn, os.O_RDWR, 0666)
if err != nil {
return nil, err
}
closew = true
st, err := w.Stat()
if err != nil {
return nil, err
}
if st.Size() != 0 {
return nil, fmt.Errorf("non empty WAL file %s exists", wn)
}
}
info, err := f.Stat()
if err != nil {
return nil, err
}
switch sz := info.Size(); {
case sz == 0:
b := make([]byte, 16)
copy(b, []byte(magic))
if _, err := f.Write(b); err != nil {
return nil, err
}
filer := lldb.Filer(lldb.NewOSFiler(f))
filer = lldb.NewInnerFiler(filer, 16)
if filer, err = lldb.NewACIDFiler(filer, w); err != nil {
return nil, err
}
a, err := lldb.NewAllocator(filer, &lldb.Options{})
if err != nil {
return nil, err
}
a.Compress = true
s := &file{
a: a,
codec: newGobCoder(),
f0: f,
f: filer,
lck: lck,
name: f.Name(),
wal: w,
}
if err = s.BeginTransaction(); err != nil {
return nil, err
}
h, err := s.Create()
if err != nil {
return nil, err
}
if h != 1 { // root
log.Panic("internal error")
}
if h, err = s.a.Alloc(make([]byte, 8)); err != nil {
return nil, err
}
if h != 2 { // id
log.Panic("internal error")
}
close, closew = false, false
return s, s.Commit()
default:
b := make([]byte, 16)
if _, err := f.Read(b); err != nil {
return nil, err
}
if string(b[:len(magic)]) != magic {
return nil, fmt.Errorf("unknown file format")
}
filer := lldb.Filer(lldb.NewOSFiler(f))
filer = lldb.NewInnerFiler(filer, 16)
if filer, err = lldb.NewACIDFiler(filer, w); err != nil {
return nil, err
}
a, err := lldb.NewAllocator(filer, &lldb.Options{})
if err != nil {
return nil, err
}
bid, err := a.Get(nil, 2) // id
if err != nil {
return nil, err
}
if len(bid) != 8 {
return nil, fmt.Errorf("corrupted id |% x|", bid)
}
id := int64(0)
for _, v := range bid {
id = (id << 8) | int64(v)
}
a.Compress = true
s := &file{
a: a,
codec: newGobCoder(),
f0: f,
f: filer,
id: id,
lck: lck,
name: f.Name(),
wal: w,
}
close, closew = false, false
return s, nil
}
}