digest: cleanup digester and verifier creation
Signed-off-by: Stephen J Day <stephen.day@docker.com>master
Stephen J Day
parent
ad80b3d492
commit
e37baed88e
|
|
@ -0,0 +1,140 @@
|
|||
package digest
|
||||
|
||||
import (
|
||||
"crypto"
|
||||
"fmt"
|
||||
"hash"
|
||||
"io"
|
||||
)
|
||||
|
||||
// Algorithm identifies and implementation of a digester by an identifier.
|
||||
// Note the that this defines both the hash algorithm used and the string
|
||||
// encoding.
|
||||
type Algorithm string
|
||||
|
||||
// supported digest types
|
||||
const (
|
||||
SHA256 Algorithm = "sha256" // sha256 with hex encoding
|
||||
SHA384 Algorithm = "sha384" // sha384 with hex encoding
|
||||
SHA512 Algorithm = "sha512" // sha512 with hex encoding
|
||||
|
||||
// Canonical is the primary digest algorithm used with the distribution
|
||||
// project. Other digests may be used but this one is the primary storage
|
||||
// digest.
|
||||
Canonical = SHA256
|
||||
)
|
||||
|
||||
var (
|
||||
// TODO(stevvooe): Follow the pattern of the standard crypto package for
|
||||
// registration of digests. Effectively, we are a registerable set and
|
||||
// common symbol access.
|
||||
|
||||
// algorithms maps values to hash.Hash implementations. Other algorithms
|
||||
// may be available but they cannot be calculated by the digest package.
|
||||
algorithms = map[Algorithm]crypto.Hash{
|
||||
SHA256: crypto.SHA256,
|
||||
SHA384: crypto.SHA384,
|
||||
SHA512: crypto.SHA512,
|
||||
}
|
||||
)
|
||||
|
||||
// Available returns true if the digest type is available for use. If this
|
||||
// returns false, New and Hash will return nil.
|
||||
func (a Algorithm) Available() bool {
|
||||
h, ok := algorithms[a]
|
||||
if !ok {
|
||||
return false
|
||||
}
|
||||
|
||||
// check availability of the hash, as well
|
||||
return h.Available()
|
||||
}
|
||||
|
||||
func (a Algorithm) String() string {
|
||||
return string(a)
|
||||
}
|
||||
|
||||
// Size returns number of bytes returned by the hash.
|
||||
func (a Algorithm) Size() int {
|
||||
h, ok := algorithms[a]
|
||||
if !ok {
|
||||
return 0
|
||||
}
|
||||
return h.Size()
|
||||
}
|
||||
|
||||
// Set implemented to allow use of Algorithm as a command line flag.
|
||||
func (a *Algorithm) Set(value string) error {
|
||||
if value == "" {
|
||||
*a = Canonical
|
||||
} else {
|
||||
// just do a type conversion, support is queried with Available.
|
||||
*a = Algorithm(value)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// New returns a new digester for the specified algorithm. If the algorithm
|
||||
// does not have a digester implementation, nil will be returned. This can be
|
||||
// checked by calling Available before calling New.
|
||||
func (a Algorithm) Digester() Digester {
|
||||
return &digester{
|
||||
alg: a,
|
||||
hash: a.Hash(),
|
||||
}
|
||||
}
|
||||
|
||||
// New is deprecated. Use Algorithm.Digester.
|
||||
func (a Algorithm) New() Digester {
|
||||
return a.Digester()
|
||||
}
|
||||
|
||||
// Hash returns a new hash as used by the algorithm. If not available, the
|
||||
// method will panic. Check Algorithm.Available() before calling.
|
||||
func (a Algorithm) Hash() hash.Hash {
|
||||
if !a.Available() {
|
||||
// NOTE(stevvooe): A missing hash is usually a programming error that
|
||||
// must be resolved at compile time. We don't import in the digest
|
||||
// package to allow users to choose their hash implementation (such as
|
||||
// when using stevvooe/resumable or a hardware accelerated package).
|
||||
//
|
||||
// Applications that may want to resolve the hash at runtime should
|
||||
// call Algorithm.Available before call Algorithm.Hash().
|
||||
panic(fmt.Sprintf("%v not available (make sure it is imported)", a))
|
||||
}
|
||||
|
||||
return algorithms[a].New()
|
||||
}
|
||||
|
||||
// FromReader returns the digest of the reader using the algorithm.
|
||||
func (a Algorithm) FromReader(rd io.Reader) (Digest, error) {
|
||||
digester := a.New()
|
||||
|
||||
if _, err := io.Copy(digester.Hash(), rd); err != nil {
|
||||
return "", err
|
||||
}
|
||||
|
||||
return digester.Digest(), nil
|
||||
}
|
||||
|
||||
// FromBytes digests the input and returns a Digest.
|
||||
func (a Algorithm) FromBytes(p []byte) Digest {
|
||||
digester := a.New()
|
||||
|
||||
if _, err := digester.Hash().Write(p); err != nil {
|
||||
// Writes to a Hash should never fail. None of the existing
|
||||
// hash implementations in the stdlib or hashes vendored
|
||||
// here can return errors from Write. Having a panic in this
|
||||
// condition instead of having FromBytes return an error value
|
||||
// avoids unnecessary error handling paths in all callers.
|
||||
panic("write to hash function returned error: " + err.Error())
|
||||
}
|
||||
|
||||
return digester.Digest()
|
||||
}
|
||||
|
||||
// FromString digests the string input and returns a Digest.
|
||||
func (a Algorithm) FromString(s string) Digest {
|
||||
return a.FromBytes([]byte(s))
|
||||
}
|
||||
|
|
@ -123,6 +123,20 @@ func (d Digest) Algorithm() Algorithm {
|
|||
return Algorithm(d[:d.sepIndex()])
|
||||
}
|
||||
|
||||
// Verifier returns a writer object that can be used to verify a stream of
|
||||
// content against the digest. If the digest is invalid, an error will be
|
||||
// returned.
|
||||
func (d Digest) Verifier() (Verifier, error) {
|
||||
if err := d.Validate(); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
return hashVerifier{
|
||||
hash: d.Algorithm().Hash(),
|
||||
digest: d,
|
||||
}, nil
|
||||
}
|
||||
|
||||
// Hex returns the hex digest portion of the digest. This will panic if the
|
||||
// underlying digest is not in a valid format.
|
||||
func (d Digest) Hex() string {
|
||||
|
|
|
|||
|
|
@ -1,141 +1,6 @@
|
|||
package digest
|
||||
|
||||
import (
|
||||
"crypto"
|
||||
"fmt"
|
||||
"hash"
|
||||
"io"
|
||||
)
|
||||
|
||||
// Algorithm identifies and implementation of a digester by an identifier.
|
||||
// Note the that this defines both the hash algorithm used and the string
|
||||
// encoding.
|
||||
type Algorithm string
|
||||
|
||||
// supported digest types
|
||||
const (
|
||||
SHA256 Algorithm = "sha256" // sha256 with hex encoding
|
||||
SHA384 Algorithm = "sha384" // sha384 with hex encoding
|
||||
SHA512 Algorithm = "sha512" // sha512 with hex encoding
|
||||
|
||||
// Canonical is the primary digest algorithm used with the distribution
|
||||
// project. Other digests may be used but this one is the primary storage
|
||||
// digest.
|
||||
Canonical = SHA256
|
||||
)
|
||||
|
||||
var (
|
||||
// TODO(stevvooe): Follow the pattern of the standard crypto package for
|
||||
// registration of digests. Effectively, we are a registerable set and
|
||||
// common symbol access.
|
||||
|
||||
// algorithms maps values to hash.Hash implementations. Other algorithms
|
||||
// may be available but they cannot be calculated by the digest package.
|
||||
algorithms = map[Algorithm]crypto.Hash{
|
||||
SHA256: crypto.SHA256,
|
||||
SHA384: crypto.SHA384,
|
||||
SHA512: crypto.SHA512,
|
||||
}
|
||||
)
|
||||
|
||||
// Available returns true if the digest type is available for use. If this
|
||||
// returns false, New and Hash will return nil.
|
||||
func (a Algorithm) Available() bool {
|
||||
h, ok := algorithms[a]
|
||||
if !ok {
|
||||
return false
|
||||
}
|
||||
|
||||
// check availability of the hash, as well
|
||||
return h.Available()
|
||||
}
|
||||
|
||||
func (a Algorithm) String() string {
|
||||
return string(a)
|
||||
}
|
||||
|
||||
// Size returns number of bytes returned by the hash.
|
||||
func (a Algorithm) Size() int {
|
||||
h, ok := algorithms[a]
|
||||
if !ok {
|
||||
return 0
|
||||
}
|
||||
return h.Size()
|
||||
}
|
||||
|
||||
// Set implemented to allow use of Algorithm as a command line flag.
|
||||
func (a *Algorithm) Set(value string) error {
|
||||
if value == "" {
|
||||
*a = Canonical
|
||||
} else {
|
||||
// just do a type conversion, support is queried with Available.
|
||||
*a = Algorithm(value)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// New returns a new digester for the specified algorithm. If the algorithm
|
||||
// does not have a digester implementation, nil will be returned. This can be
|
||||
// checked by calling Available before calling New.
|
||||
func (a Algorithm) New() Digester {
|
||||
return &digester{
|
||||
alg: a,
|
||||
hash: a.Hash(),
|
||||
}
|
||||
}
|
||||
|
||||
// Hash returns a new hash as used by the algorithm. If not available, the
|
||||
// method will panic. Check Algorithm.Available() before calling.
|
||||
func (a Algorithm) Hash() hash.Hash {
|
||||
if !a.Available() {
|
||||
// NOTE(stevvooe): A missing hash is usually a programming error that
|
||||
// must be resolved at compile time. We don't import in the digest
|
||||
// package to allow users to choose their hash implementation (such as
|
||||
// when using stevvooe/resumable or a hardware accelerated package).
|
||||
//
|
||||
// Applications that may want to resolve the hash at runtime should
|
||||
// call Algorithm.Available before call Algorithm.Hash().
|
||||
panic(fmt.Sprintf("%v not available (make sure it is imported)", a))
|
||||
}
|
||||
|
||||
return algorithms[a].New()
|
||||
}
|
||||
|
||||
// FromReader returns the digest of the reader using the algorithm.
|
||||
func (a Algorithm) FromReader(rd io.Reader) (Digest, error) {
|
||||
digester := a.New()
|
||||
|
||||
if _, err := io.Copy(digester.Hash(), rd); err != nil {
|
||||
return "", err
|
||||
}
|
||||
|
||||
return digester.Digest(), nil
|
||||
}
|
||||
|
||||
// FromBytes digests the input and returns a Digest.
|
||||
func (a Algorithm) FromBytes(p []byte) Digest {
|
||||
digester := a.New()
|
||||
|
||||
if _, err := digester.Hash().Write(p); err != nil {
|
||||
// Writes to a Hash should never fail. None of the existing
|
||||
// hash implementations in the stdlib or hashes vendored
|
||||
// here can return errors from Write. Having a panic in this
|
||||
// condition instead of having FromBytes return an error value
|
||||
// avoids unnecessary error handling paths in all callers.
|
||||
panic("write to hash function returned error: " + err.Error())
|
||||
}
|
||||
|
||||
return digester.Digest()
|
||||
}
|
||||
|
||||
// FromString digests the string input and returns a Digest.
|
||||
func (a Algorithm) FromString(s string) Digest {
|
||||
return a.FromBytes([]byte(s))
|
||||
}
|
||||
|
||||
// TODO(stevvooe): Allow resolution of verifiers using the digest type and
|
||||
// this registration system.
|
||||
import "hash"
|
||||
|
||||
// Digester calculates the digest of written data. Writes should go directly
|
||||
// to the return value of Hash, while calling Digest will return the current
|
||||
|
|
|
|||
|
|
@ -17,8 +17,7 @@ type Verifier interface {
|
|||
Verified() bool
|
||||
}
|
||||
|
||||
// NewDigestVerifier returns a verifier that compares the written bytes
|
||||
// against a passed in digest.
|
||||
// NewDigestVerifier is deprecated. Please use Digest.Verifier.
|
||||
func NewDigestVerifier(d Digest) (Verifier, error) {
|
||||
if err := d.Validate(); err != nil {
|
||||
return nil, err
|
||||
|
|
|
|||
|
|
@ -552,7 +552,7 @@ func testBlobAPI(t *testing.T, env *testEnv, args blobArgs) *testEnv {
|
|||
})
|
||||
|
||||
// Verify the body
|
||||
verifier, err := digest.NewDigestVerifier(layerDigest)
|
||||
verifier, err := layerDigest.Verifier()
|
||||
if err != nil {
|
||||
t.Fatalf("unexpected error getting digest verifier: %s", err)
|
||||
}
|
||||
|
|
|
|||
|
|
@ -236,7 +236,7 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
|
|||
if !verified {
|
||||
digester := digest.Canonical.New()
|
||||
|
||||
digestVerifier, err := digest.NewDigestVerifier(desc.Digest)
|
||||
digestVerifier, err := desc.Digest.Verifier()
|
||||
if err != nil {
|
||||
return distribution.Descriptor{}, err
|
||||
}
|
||||
|
|
|
|||
|
|
@ -41,7 +41,7 @@ func TestSimpleRead(t *testing.T) {
|
|||
t.Fatalf("error allocating file reader: %v", err)
|
||||
}
|
||||
|
||||
verifier, err := digest.NewDigestVerifier(dgst)
|
||||
verifier, err := dgst.Verifier()
|
||||
if err != nil {
|
||||
t.Fatalf("error getting digest verifier: %s", err)
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue