move dependencies to vendor

vendor/github.com/docker/distribution/errors.go

@@ -0,0 +1,82 @@
+package distribution
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/docker/distribution/digest"
+)
+
+// ErrRepositoryUnknown is returned if the named repository is not known by
+// the registry.
+type ErrRepositoryUnknown struct {
+	Name string
+}
+
+func (err ErrRepositoryUnknown) Error() string {
+	return fmt.Sprintf("unknown repository name=%s", err.Name)
+}
+
+// ErrRepositoryNameInvalid should be used to denote an invalid repository
+// name. Reason may set, indicating the cause of invalidity.
+type ErrRepositoryNameInvalid struct {
+	Name   string
+	Reason error
+}
+
+func (err ErrRepositoryNameInvalid) Error() string {
+	return fmt.Sprintf("repository name %q invalid: %v", err.Name, err.Reason)
+}
+
+// ErrManifestUnknown is returned if the manifest is not known by the
+// registry.
+type ErrManifestUnknown struct {
+	Name string
+	Tag  string
+}
+
+func (err ErrManifestUnknown) Error() string {
+	return fmt.Sprintf("unknown manifest name=%s tag=%s", err.Name, err.Tag)
+}
+
+// ErrManifestUnknownRevision is returned when a manifest cannot be found by
+// revision within a repository.
+type ErrManifestUnknownRevision struct {
+	Name     string
+	Revision digest.Digest
+}
+
+func (err ErrManifestUnknownRevision) Error() string {
+	return fmt.Sprintf("unknown manifest name=%s revision=%s", err.Name, err.Revision)
+}
+
+// ErrManifestUnverified is returned when the registry is unable to verify
+// the manifest.
+type ErrManifestUnverified struct{}
+
+func (ErrManifestUnverified) Error() string {
+	return fmt.Sprintf("unverified manifest")
+}
+
+// ErrManifestVerification provides a type to collect errors encountered
+// during manifest verification. Currently, it accepts errors of all types,
+// but it may be narrowed to those involving manifest verification.
+type ErrManifestVerification []error
+
+func (errs ErrManifestVerification) Error() string {
+	var parts []string
+	for _, err := range errs {
+		parts = append(parts, err.Error())
+	}
+
+	return fmt.Sprintf("errors verifying manifest: %v", strings.Join(parts, ","))
+}
+
+// ErrManifestBlobUnknown returned when a referenced blob cannot be found.
+type ErrManifestBlobUnknown struct {
+	Digest digest.Digest
+}
+
+func (err ErrManifestBlobUnknown) Error() string {
+	return fmt.Sprintf("unknown blob %v on manifest", err.Digest)
+}