code: func (c *Corpus) mergeWholeToFileRow(k, v []byte) error {
  	pair := k[len("wholetofile|"):]
  	pipe := bytes.IndexByte(pair, '|')
  	if pipe < 0 {
  		return fmt.Errorf("bogus row %q = %q", k, v)
  	}
  	wholeRef, ok1 := blob.ParseBytes(pair[:pipe])
  	fileRef, ok2 := blob.ParseBytes(pair[pipe+1:])
  	if !ok1 || !ok2 {
  		return fmt.Errorf("bogus row %q = %q", k, v)
  	}
  	c.fileWholeRef[fileRef] = wholeRef
  	if c.building && !c.hasLegacySHA1 {
  		if bytes.HasPrefix(pair, sha1Prefix) {
  			c.hasLegacySHA1 = true
  		}
  	}
  	return nil
  }
docs: // "wholetofile|sha1-17b53c7c3e664d3613dfdce50ef1f2a09e8f04b5|sha1-fb88f3eab3acfcf3cfc8cd77ae4366f6f975d227" -> "1"