move container-related functions out of kpod and into libkpod

Signed-off-by: Ryan Cole <rcyoalne@gmail.com>

libkpod/container.go

@@ -0,0 +1,48 @@
+package libkpod
+
+import (
+	cstorage "github.com/containers/storage"
+)
+
+// FindContainer searches for a container with the given name or ID in the given store
+func FindContainer(store cstorage.Store, container string) (*cstorage.Container, error) {
+	ctrStore, err := store.ContainerStore()
+	if err != nil {
+		return nil, err
+	}
+	return ctrStore.Get(container)
+}
+
+// GetContainerTopLayerID gets the ID of the top layer of the given container
+func GetContainerTopLayerID(store cstorage.Store, containerID string) (string, error) {
+	ctr, err := FindContainer(store, containerID)
+	if err != nil {
+		return "", err
+	}
+	return ctr.LayerID, nil
+}
+
+// GetContainerRwSize Gets the size of the mutable top layer of the container
+func GetContainerRwSize(store cstorage.Store, containerID string) (int64, error) {
+	ctrStore, err := store.ContainerStore()
+	if err != nil {
+		return 0, err
+	}
+	container, err := ctrStore.Get(containerID)
+	if err != nil {
+		return 0, err
+	}
+	lstore, err := store.LayerStore()
+	if err != nil {
+		return 0, err
+	}
+
+	// Get the size of the top layer by calculating the size of the diff
+	// between the layer and its parent.  The top layer of a container is
+	// the only RW layer, all others are immutable
+	layer, err := lstore.Get(container.LayerID)
+	if err != nil {
+		return 0, err
+	}
+	return lstore.DiffSize(layer.Parent, layer.ID)
+}

libkpod/image/image.go

@@ -3,7 +3,6 @@ package image
 import (
 	is "github.com/containers/image/storage"
 	"github.com/containers/storage"
-	"github.com/kubernetes-incubator/cri-o/libkpod/image"
 	"github.com/pkg/errors"
 )
 
@@ -46,8 +45,8 @@ func Size(store storage.Store, img storage.Image) (int64, error) {
 }
 
 // TopLayer returns the ID of the top layer of the image
-func getTopLayerID(img storage.Image) (string, error) {
-	metadata, err := image.ParseMetadata(img)
+func GetTopLayerID(img storage.Image) (string, error) {
+	metadata, err := ParseMetadata(img)
 	if err != nil {
 		return "", err
 	}