Support for ingest namespacing

Move content status to list statuses and add single status
to interface.
Updates API to support list statuses and status
Updates snapshot key creation to be generic

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

content/content.go

@@ -58,19 +58,19 @@ type Manager interface {
 
 	// Delete removes the content from the store.
 	Delete(ctx context.Context, dgst digest.Digest) error
+}
 
-	// Status returns the status of any active ingestions whose ref match the
+// IngestManager provides methods for managing ingests.
+type IngestManager interface {
+	// Status returns the status of the provided ref.
+	Status(ctx context.Context, ref string) (Status, error)
+
+	// ListStatuses returns the status of any active ingestions whose ref match the
 	// provided regular expression. If empty, all active ingestions will be
 	// returned.
-	//
-	// TODO(stevvooe): Status may be slighly out of place here. If this remains
-	// here, we should remove Manager and just define these on store.
-	Status(ctx context.Context, re string) ([]Status, error)
+	ListStatuses(ctx context.Context, ref string) ([]Status, error)
 
 	// Abort completely cancels the ingest operation targeted by ref.
-	//
-	// TODO(stevvooe): Same consideration as above. This should really be
-	// restricted to an ingest management interface.
 	Abort(ctx context.Context, ref string) error
 }
 
@@ -86,6 +86,7 @@ type Writer interface {
 // are commonly provided by complete implementations.
 type Store interface {
 	Manager
-	Ingester
 	Provider
+	IngestManager
+	Ingester
 }