func (s *storage) Fetch(br blob.Ref) (io.ReadCloser, uint32, error) {
meta, err := s.meta(br)
if err != nil {
return nil, 0, err
}
if meta.file >= len(s.fds) {
return nil, 0, fmt.Errorf("diskpacked: attempt to fetch blob from out of range pack file %d > %d", meta.file, len(s.fds))
}
rac := s.fds[meta.file]
var rs io.ReadSeeker = io.NewSectionReader(rac, meta.offset, int64(meta.size))
fn := rac.Name()
// Ensure entry is in map.
readVar.Add(fn, 0)
if v, ok := readVar.Get(fn).(*expvar.Int); ok {
rs = types.NewStatsReadSeeker(v, rs)
}
readTotVar.Add(s.root, 0)
if v, ok := readTotVar.Get(s.root).(*expvar.Int); ok {
rs = types.NewStatsReadSeeker(v, rs)
}
rsc := struct {
io.ReadSeeker
io.Closer
}{
rs,
types.NopCloser,
}
return rsc, meta.size, nil
}
// length of -1 means all
func (s *storage) fetch(br blob.Ref, offset, length int64) (rc io.ReadCloser, size uint32, err error) {
meta, err := s.meta(br)
if err != nil {
return nil, 0, err
}
if meta.file >= len(s.fds) {
return nil, 0, fmt.Errorf("diskpacked: attempt to fetch blob from out of range pack file %d > %d", meta.file, len(s.fds))
}
rac := s.fds[meta.file]
var rs io.ReadSeeker
if length == -1 {
// normal Fetch mode
rs = io.NewSectionReader(rac, meta.offset, int64(meta.size))
} else {
if offset > int64(meta.size) {
return nil, 0, blob.ErrOutOfRangeOffsetSubFetch
} else if offset+length > int64(meta.size) {
length = int64(meta.size) - offset
}
rs = io.NewSectionReader(rac, meta.offset+offset, length)
}
fn := rac.Name()
// Ensure entry is in map.
readVar.Add(fn, 0)
if v, ok := readVar.Get(fn).(*expvar.Int); ok {
rs = types.NewStatsReadSeeker(v, rs)
}
readTotVar.Add(s.root, 0)
if v, ok := readTotVar.Get(s.root).(*expvar.Int); ok {
rs = types.NewStatsReadSeeker(v, rs)
}
rsc := struct {
io.ReadSeeker
io.Closer
}{
rs,
types.NopCloser,
}
return rsc, meta.size, nil
}
