// OpenFromFiler is like Open but it accepts an arbitrary backing storage
// provided by filer.
func OpenFromFiler(filer lldb.Filer, 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
}
}
}()
name := filer.Name()
if err = opts.check(name, false, true); err != nil {
return
}
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{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
}
