reader will return a reader depending on the capabilities of the source reader: - if it supports seeking it will seek to the desired offset and return the same reader - if it doesn't support seeking it will close a possible existing one and open at the desired offset - if there's no reader associate
(offset, end int64, closeOpen bool)
| 350 | // - if it doesn't support seeking it will close a possible existing one and open at the desired offset |
| 351 | // - if there's no reader associated with this worker, it will create one |
| 352 | func (w *worker) reader(offset, end int64, closeOpen bool) (io.ReadCloser, error) { |
| 353 | var err error |
| 354 | r := w.rc |
| 355 | if w.rc == nil { |
| 356 | r, err = w.r.cacheFs().openRateLimited(func() (io.ReadCloser, error) { |
| 357 | return w.r.cachedObject.Object.Open(w.r.ctx, &fs.RangeOption{Start: offset, End: end - 1}) |
| 358 | }) |
| 359 | if err != nil { |
| 360 | return nil, err |
| 361 | } |
| 362 | return r, nil |
| 363 | } |
| 364 | |
| 365 | if !closeOpen { |
| 366 | if do, ok := r.(fs.RangeSeeker); ok { |
| 367 | _, err = do.RangeSeek(w.r.ctx, offset, io.SeekStart, end-offset) |
| 368 | return r, err |
| 369 | } else if do, ok := r.(io.Seeker); ok { |
| 370 | _, err = do.Seek(offset, io.SeekStart) |
| 371 | return r, err |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | _ = w.rc.Close() |
| 376 | return w.r.cacheFs().openRateLimited(func() (io.ReadCloser, error) { |
| 377 | r, err = w.r.cachedObject.Object.Open(w.r.ctx, &fs.RangeOption{Start: offset, End: end - 1}) |
| 378 | if err != nil { |
| 379 | return nil, err |
| 380 | } |
| 381 | return r, nil |
| 382 | }) |
| 383 | } |
| 384 | |
| 385 | // run is the main loop for the worker which receives offsets to preload |
| 386 | func (w *worker) run() { |