// LoadSegs laods all existing segment files available
// matching provided base path. The base path should contain
// the path to the segment file and the segment file prefix.
// example: "/path/to/segment/files/prefix_"
func LoadSegs(base string, size int64, lock bool) (segs []*Segment, err error) {
segs = []*Segment{}
for i := 0; true; i++ {
path := base + strconv.Itoa(i)
file, err := os.OpenFile(path, os.O_RDWR, 0644)
if err != nil {
break
}
// don't need this
defer file.Close()
seg, err := memmap.MapFile(file, size)
if err != nil {
return nil, err
}
if lock {
if err := seg.Lock(); err != nil {
go seg.Close()
return nil, err
}
}
segs = append(segs, &Segment{seg, 0})
}
return segs, nil
}
// ensure makes sure that segments upto given index exists and are valid.
// This will check from current segment length upto given position.
// This will also pre allocate an additional segment file/mmap.
func (s *Store) ensure(n int64) (err error) {
// +1 preallocate
num := int(n) + 1
// fast path
s.segmx.RLock()
if num < len(s.segs) {
s.segmx.RUnlock()
return nil
}
s.segmx.RUnlock()
// slow path
s.segmx.Lock()
defer s.segmx.Unlock()
available := len(s.segs)
if num < available {
return nil
}
for i := available; i <= num; i++ {
path := s.base + strconv.Itoa(i)
file, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE, 0644)
if err != nil {
return err
}
// don't need this
defer file.Close()
seg, err := memmap.MapFile(file, s.size)
if err != nil {
return err
}
if err := seg.Lock(); err != nil {
go seg.Close()
return err
}
s.segs = append(s.segs, &Segment{seg, 0})
}
return nil
}