Vendor in latest c/common

Signed-off-by: Ashley Cui <acui@redhat.com>

vendor/github.com/containers/image/v5/internal/signer/signer.go

@@ -0,0 +1,47 @@
+package signer
+
+import (
+	"context"
+
+	"github.com/containers/image/v5/docker/reference"
+	"github.com/containers/image/v5/internal/signature"
+)
+
+// Signer is an object, possibly carrying state, that can be used by copy.Image to sign one or more container images.
+// This type is visible to external callers, so it has no public fields or methods apart from Close().
+//
+// The owner of a Signer must call Close() when done.
+type Signer struct {
+	implementation SignerImplementation
+}
+
+// NewSigner creates a public Signer from a SignerImplementation
+func NewSigner(impl SignerImplementation) *Signer {
+	return &Signer{implementation: impl}
+}
+
+func (s *Signer) Close() error {
+	return s.implementation.Close()
+}
+
+// ProgressMessage returns a human-readable sentence that makes sense to write before starting to create a single signature.
+// Alternatively, should SignImageManifest be provided a logging writer of some kind?
+func ProgressMessage(signer *Signer) string {
+	return signer.implementation.ProgressMessage()
+}
+
+// SignImageManifest invokes a SignerImplementation.
+// This is a function, not a method, so that it can only be called by code that is allowed to import this internal subpackage.
+func SignImageManifest(ctx context.Context, signer *Signer, manifest []byte, dockerReference reference.Named) (signature.Signature, error) {
+	return signer.implementation.SignImageManifest(ctx, manifest, dockerReference)
+}
+
+// SignerImplementation is an object, possibly carrying state, that can be used by copy.Image to sign one or more container images.
+// This interface is distinct from Signer so that implementations can be created outside of this package.
+type SignerImplementation interface {
+	// ProgressMessage returns a human-readable sentence that makes sense to write before starting to create a single signature.
+	ProgressMessage() string
+	// SignImageManifest creates a new signature for manifest m as dockerReference.
+	SignImageManifest(ctx context.Context, m []byte, dockerReference reference.Named) (signature.Signature, error)
+	Close() error
+}