Use reference package internally

Most places in the registry were using string types to refer to
repository names. This changes them to use reference.Named, so the type
system can enforce validation of the naming rules.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

registry/proxy/scheduler/scheduler.go

@@ -7,6 +7,8 @@ import (
 	"time"
 
 	"github.com/docker/distribution/context"
+	"github.com/docker/distribution/digest"
+	"github.com/docker/distribution/reference"
 	"github.com/docker/distribution/registry/storage/driver"
 )
 
@@ -80,19 +82,19 @@ func (ttles *TTLExpirationScheduler) OnManifestExpire(f expiryFunc) {
 }
 
 // AddBlob schedules a blob cleanup after ttl expires
-func (ttles *TTLExpirationScheduler) AddBlob(dgst string, ttl time.Duration) error {
+func (ttles *TTLExpirationScheduler) AddBlob(dgst digest.Digest, ttl time.Duration) error {
 	ttles.Lock()
 	defer ttles.Unlock()
 
 	if ttles.stopped {
 		return fmt.Errorf("scheduler not started")
 	}
-	ttles.add(dgst, ttl, entryTypeBlob)
+	ttles.add(dgst.String(), ttl, entryTypeBlob)
 	return nil
 }
 
 // AddManifest schedules a manifest cleanup after ttl expires
-func (ttles *TTLExpirationScheduler) AddManifest(repoName string, ttl time.Duration) error {
+func (ttles *TTLExpirationScheduler) AddManifest(repoName reference.Named, ttl time.Duration) error {
 	ttles.Lock()
 	defer ttles.Unlock()
 
@@ -100,7 +102,7 @@ func (ttles *TTLExpirationScheduler) AddManifest(repoName string, ttl time.Durat
 		return fmt.Errorf("scheduler not started")
 	}
 
-	ttles.add(repoName, ttl, entryTypeManifest)
+	ttles.add(repoName.Name(), ttl, entryTypeManifest)
 	return nil
 }