// Open opens the named kv DB file for reading/writing. It
// creates the file if it does not exist yet.
func Open(dbFile string, opts *kv.Options) (*kv.DB, error) {
createOpen := kv.Open
verb := "opening"
if _, err := os.Stat(dbFile); os.IsNotExist(err) {
createOpen = kv.Create
verb = "creating"
}
if opts == nil {
opts = &kv.Options{}
}
if opts.Locker == nil {
opts.Locker = func(dbFile string) (io.Closer, error) {
lkfile := dbFile + ".lock"
cl, err := lock.Lock(lkfile)
if err != nil {
return nil, fmt.Errorf("failed to acquire lock on %s: %v", lkfile, err)
}
return cl, nil
}
}
if v, _ := strconv.ParseBool(os.Getenv("CAMLI_KV_VERIFY")); v {
opts.VerifyDbBeforeOpen = true
opts.VerifyDbAfterOpen = true
opts.VerifyDbBeforeClose = true
opts.VerifyDbAfterClose = true
}
db, err := createOpen(dbFile, opts)
if err != nil {
return nil, fmt.Errorf("error %s %s: %v", verb, dbFile, err)
}
return db, nil
}
// openForWrite will create or open pack file n for writes, create a lock
// visible external to the process and seek to the end of the file ready for
// appending new data.
// This function is not thread safe, s.mu should be locked by the caller.
func (s *storage) openForWrite(n int) error {
fn := s.filename(n)
l, err := lock.Lock(fn + ".lock")
if err != nil {
return err
}
f, err := os.OpenFile(fn, os.O_RDWR|os.O_CREATE, 0666)
if err != nil {
l.Close()
return err
}
openFdsVar.Add(s.root, 1)
debug.Printf("diskpacked: opened for write %q", fn)
s.size, err = f.Seek(0, os.SEEK_END)
if err != nil {
return err
}
s.writer = f
s.writeLock = l
return nil
}