distribution/digest/verifiers.go

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package digest
import (
"hash"
"io"
)
// Verifier presents a general verification interface to be used with message
// digests and other byte stream verifications. Users instantiate a Verifier
// from one of the various methods, write the data under test to it then check
// the result with the Verified method.
type Verifier interface {
io.Writer
// Verified will return true if the content written to Verifier matches
// the digest.
Verified() bool
}
// NewDigestVerifier returns a verifier that compares the written bytes
// against a passed in digest.
func NewDigestVerifier(d Digest) (Verifier, error) {
if err := d.Validate(); err != nil {
return nil, err
}
return hashVerifier{
hash: d.Algorithm().Hash(),
digest: d,
}, nil
}
type hashVerifier struct {
digest Digest
hash hash.Hash
}
func (hv hashVerifier) Write(p []byte) (n int, err error) {
return hv.hash.Write(p)
}
func (hv hashVerifier) Verified() bool {
return hv.digest == NewDigest(hv.digest.Algorithm(), hv.hash)
}