Function EnumerateAllFrom

pkg/blobserver/enumerate.go:34–67

EnumerateAllFrom is like EnumerateAll, but takes an after parameter.

(ctx context.Context, src BlobEnumerator, after string, fn func(blob.SizedRef) error)

// EnumerateAllFrom is like EnumerateAll, but takes an after parameter.
func EnumerateAllFrom(ctx context.Context, src BlobEnumerator, after string, fn func(blob.SizedRef) error) error {
	const batchSize = 1000
	var mu sync.Mutex // protects returning with an error while fn is still running
	errc := make(chan error, 1)
	for {
		ch := make(chan blob.SizedRef, 16)
		n := 0
		go func() {
			var err error
			for sb := range ch {
				if err != nil {
					continue
				}
				mu.Lock()
				err = fn(sb)
				mu.Unlock()
				after = sb.Ref.String()
				n++
			}
			errc <- err
		}()
		err := src.EnumerateBlobs(ctx, ch, after, batchSize)
		if err != nil {
			mu.Lock() // make sure fn callback finished; no need to unlock
			return err
		}
		if err := <-errc; err != nil {
			return err
		}
		if n == 0 {
			return nil
		}
	}
}

// RefTypes returns a list of blobref types appearing on the provided enumerator.
// A blobref type is a string like "sha1", or whatever is on the left side