// Open opens the named DB file for reading/writing. If successful, methods on
// the returned DB can be used for I/O; the associated file descriptor has mode
// os.O_RDWR. If there is an error, it will be of type *os.PathError.
//
// For the meaning of opts please see documentation of Options.
func Open(name string, opts *Options) (db *DB, err error) {
defer func() {
lock := opts.lock
if err != nil && lock != nil {
n := lock.Name()
lock.Close()
os.Remove(n)
db = nil
}
if err != nil {
if db != nil {
db.Close()
db = nil
}
}
}()
if err = opts.check(name, false, true); err != nil {
return
}
f, err := os.OpenFile(name, os.O_RDWR, 0666)
if err != nil {
return
}
filer := lldb.Filer(lldb.NewSimpleFileFiler(f))
sz, err := filer.Size()
if err != nil {
return
}
if sz%16 != 0 {
return nil, &os.PathError{Op: "dbm.Open:", Path: name, Err: fmt.Errorf("file size %d(%#x) is not 0 (mod 16)", sz, sz)}
}
var b [16]byte
if n, err := filer.ReadAt(b[:], 0); n != 16 || err != nil {
return nil, &os.PathError{Op: "dbm.Open.ReadAt", Path: name, Err: err}
}
var h header
if err = h.rd(b[:]); err != nil {
return nil, &os.PathError{Op: "dbm.Open:validate header", Path: name, Err: err}
}
db = &DB{f: f, lock: opts.lock, closed: make(chan bool)}
if filer, err = opts.acidFiler(db, filer); err != nil {
return nil, err
}
db.filer = filer
switch h.ver {
default:
return nil, &os.PathError{Op: "dbm.Open", Path: name, Err: fmt.Errorf("unknown dbm file format version %#x", h.ver)}
case 0x00:
return open00(name, db)
}
}
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
}
}
// Open opens the named DB file for reading/writing. If successful, methods on
// the returned DB can be used for I/O; the associated file descriptor has mode
// os.O_RDWR. If there is an error, it will be of type *os.PathError.
//
// Note: While a DB is opened, it is locked and cannot be simultaneously opened
// again.
//
// For the meaning of opts please see documentation of Options.
func Open(name string, opts *Options) (db *DB, err error) {
opts = opts.clone()
opts._ACID = _ACIDFull
defer func() {
if db != nil {
db.opts = opts
}
}()
defer func() {
lock := opts.lock
if err != nil && lock != nil {
lock.Close()
db = nil
}
if err != nil {
if db != nil {
db.Close()
db = nil
}
}
}()
if err = opts.check(name, false, true); err != nil {
return
}
f, err := os.OpenFile(name, os.O_RDWR, 0666)
if err != nil {
return
}
filer := lldb.Filer(lldb.NewSimpleFileFiler(f))
sz, err := filer.Size()
if err != nil {
return
}
if sz%16 != 0 {
return nil, &os.PathError{Op: "kv.Open:", Path: name, Err: fmt.Errorf("file size %d(%#x) is not 0 (mod 16)", sz, sz)}
}
var b [16]byte
if n, err := filer.ReadAt(b[:], 0); n != 16 || err != nil {
return nil, &os.PathError{Op: "kv.Open.ReadAt", Path: name, Err: err}
}
var h header
if err = h.rd(b[:]); err != nil {
return nil, &os.PathError{Op: "kv.Open:validate header", Path: name, Err: err}
}
db = &DB{f: f, lock: opts.lock}
if filer, err = opts.acidFiler(db, filer); err != nil {
return nil, err
}
db.filer = filer
switch h.ver {
default:
return nil, &os.PathError{Op: "kv.Open", Path: name, Err: fmt.Errorf("unknown/unsupported kv file format version %#x", h.ver)}
case 0x00:
if _, err = open00(name, db); err != nil {
return nil, err
}
}
db.root, err = lldb.OpenBTree(db.alloc, opts.Compare, 1)
db.wal = opts.wal
if opts.VerifyDbAfterOpen {
err = verifyAllocator(db.alloc)
}
return
}