Method startValidatePrefix

pkg/server/sync.go:836–890

doDest is false for source and true for dest.

(ctx context.Context, pfx string, doDest bool)

// doDest is false for source and true for dest.
func (sh *SyncHandler) startValidatePrefix(ctx context.Context, pfx string, doDest bool) (<-chan blob.SizedRef, <-chan error) {
	var e blobserver.BlobEnumerator
	if doDest {
		e = sh.to
	} else {
		e = sh.from
	}
	c := make(chan blob.SizedRef, 64)
	errc := make(chan error, 1)
	go func() {
		defer close(c)
		var last string // last blobref seen; to double check storage's enumeration works correctly.
		err := blobserver.EnumerateAllFrom(ctx, e, pfx, func(sb blob.SizedRef) error {
			// Just double-check that the storage target is returning sorted results correctly.
			brStr := sb.Ref.String()
			if brStr < pfx {
				log.Fatalf("Storage target %T enumerate not behaving: %q < requested prefix %q", e, brStr, pfx)
			}
			if last != "" && last >= brStr {
				log.Fatalf("Storage target %T enumerate not behaving: previous %q >= current %q", e, last, brStr)
			}
			last = brStr

			// TODO: could add a more efficient method on blob.Ref to do this,
			// that doesn't involve call String().
			if !strings.HasPrefix(brStr, pfx) {
				return errNotPrefix
			}
			select {
			case c <- sb:
				sh.mu.Lock()
				if doDest {
					sh.vdestCount++
					sh.vdestBytes += int64(sb.Size)
				} else {
					sh.vsrcCount++
					sh.vsrcBytes += int64(sb.Size)
				}
				sh.mu.Unlock()
				return nil
			case <-ctx.Done():
				return ctx.Err()
			}
		})
		if err == errNotPrefix {
			err = nil
		}
		if err != nil {
			// Send a zero value to shut down ListMissingDestinationBlobs.
			c <- blob.SizedRef{}
		}
		errc <- err
	}()
	return c, errc
}

func (sh *SyncHandler) shardPrefixes() []string {
	var pfx []string