fix podman container exists and diff for storage containers

Current these commands only check if a container exists in libpod. With
this fix, the commands will also check if they are in containers/storage.

This allows users to look at differences within a buildah or CRI-O container.

Currently buildah diff does not exists, so this helps out in that situation
as well as in CRI-O since the cri does not implement a diff command.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

2 files changed, 16 insertions, 8 deletions

diff --git a/libpod/diff.go b/libpod/diff.go
index 5335d701c..43f4d2e96 100644
--- a/libpod/diff.go
+++ b/libpod/diff.go
@@ -62,18 +62,22 @@ func (r *Runtime) ApplyDiffTarStream(to string, diff io.Reader) error {
 func (r *Runtime) getLayerID(id string) (string, error) {
 	var toLayer string
 	toImage, err := r.imageRuntime.NewFromLocal(id)
+	if err == nil {
+		return toImage.TopLayer(), nil
+	}
+
+	targetID, err := r.store.Lookup(id)
 	if err != nil {
-		toCtr, err := r.store.Container(id)
+		targetID = id
+	}
+	toCtr, err := r.store.Container(targetID)
+	if err != nil {
+		toLayer, err = layers.FullID(r.store, targetID)
 		if err != nil {
-			toLayer, err = layers.FullID(r.store, id)
-			if err != nil {
-				return "", errors.Errorf("layer, image, or container %s does not exist", id)
-			}
-		} else {
-			toLayer = toCtr.LayerID
+			return "", errors.Errorf("layer, image, or container %s does not exist", id)
 		}
 	} else {
-		toLayer = toImage.TopLayer()
+		toLayer = toCtr.LayerID
 	}
 	return toLayer, nil
 }
diff --git a/libpod/runtime_cstorage.go b/libpod/runtime_cstorage.go
index 03eebeefc..61fdd42d3 100644
--- a/libpod/runtime_cstorage.go
+++ b/libpod/runtime_cstorage.go
@@ -52,6 +52,10 @@ func (r *Runtime) ListStorageContainers() ([]*StorageContainer, error) {
 	return finalCtrs, nil
 }
 
+func (r *Runtime) StorageContainer(idOrName string) (*storage.Container, error) {
+	return r.store.Container(idOrName)
+}
+
 // RemoveStorageContainer removes a container from c/storage.
 // The container WILL NOT be removed if it exists in libpod.
 // Accepts ID or full name of container.