Function newDigestingReader

copy/digesting_reader.go:23–41

newDigestingReader returns an io.Reader implementation with contents of source, which will eventually return a non-EOF error or set validationSucceeded/validationFailed to true if the source stream does/does not match expectedDigest. (neither is set if EOF is never reached).

(source io.Reader, expectedDigest digest.Digest)

// or set validationSucceeded/validationFailed to true if the source stream does/does not match expectedDigest.
// (neither is set if EOF is never reached).
func newDigestingReader(source io.Reader, expectedDigest digest.Digest) (*digestingReader, error) {
	var digester digest.Digester
	if err := expectedDigest.Validate(); err != nil {
		return nil, fmt.Errorf("invalid digest specification %q: %w", expectedDigest, err)
	}
	digestAlgorithm := expectedDigest.Algorithm()
	if !digestAlgorithm.Available() {
		return nil, fmt.Errorf("invalid digest specification %q: unsupported digest algorithm %q", expectedDigest, digestAlgorithm)
	}
	digester = digestAlgorithm.Digester()

	return &digestingReader{
		source:           source,
		digester:         digester,
		hash:             digester.Hash(),
		expectedDigest:   expectedDigest,
		validationFailed: false,
	}, nil
}

func (d *digestingReader) Read(p []byte) (int, error) {
	n, err := d.source.Read(p)