move driver and image metadata to libkpod

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

libkpod/image/image.go

@@ -0,0 +1 @@
+package image

libkpod/image/metadata.go

@@ -0,0 +1,32 @@
+package image
+
+import (
+	"encoding/json"
+	"strings"
+	"time"
+
+	"github.com/containers/image/types"
+	"github.com/containers/storage"
+)
+
+// Metadata stores all of the metadata for an image
+type Metadata struct {
+	Tag            string              `json:"tag"`
+	CreatedTime    time.Time           `json:"created-time"`
+	ID             string              `json:"id"`
+	Blobs          []types.BlobInfo    `json:"blob-list"`
+	Layers         map[string][]string `json:"layers"`
+	SignatureSizes []string            `json:"signature-sizes"`
+}
+
+// ParseMetadata takes an image, parses the json stored in it's metadata
+// field, and converts it to a Metadata struct
+func ParseMetadata(image storage.Image) (Metadata, error) {
+	var m Metadata
+
+	dec := json.NewDecoder(strings.NewReader(image.Metadata))
+	if err := dec.Decode(&m); err != nil {
+		return Metadata{}, err
+	}
+	return m, nil
+}