2 files changed, 205 insertions, 0 deletions
diff --git a/image/v1/imagev1.go b/image/v1/imagev1.go
new file mode 100644
index 0000000..0e8a23c
--- /dev/null
+++ b/image/v1/imagev1.go
@@ -0,0 +1,150 @@
+package v1
+
+import (
+	"encoding/json"
+	"reflect"
+	"strings"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/docker/api/types/versions"
+	"github.com/docker/docker/image"
+	"github.com/docker/docker/layer"
+	"github.com/docker/docker/pkg/stringid"
+	"github.com/opencontainers/go-digest"
+)
+
+// noFallbackMinVersion is the minimum version for which v1compatibility
+// information will not be marshaled through the Image struct to remove
+// blank fields.
+var noFallbackMinVersion = "1.8.3"
+
+// HistoryFromConfig creates a History struct from v1 configuration JSON
+func HistoryFromConfig(imageJSON []byte, emptyLayer bool) (image.History, error) {
+	h := image.History{}
+	var v1Image image.V1Image
+	if err := json.Unmarshal(imageJSON, &v1Image); err != nil {
+		return h, err
+	}
+
+	return image.History{
+		Author:     v1Image.Author,
+		Created:    v1Image.Created,
+		CreatedBy:  strings.Join(v1Image.ContainerConfig.Cmd, " "),
+		Comment:    v1Image.Comment,
+		EmptyLayer: emptyLayer,
+	}, nil
+}
+
+// CreateID creates an ID from v1 image, layerID and parent ID.
+// Used for backwards compatibility with old clients.
+func CreateID(v1Image image.V1Image, layerID layer.ChainID, parent digest.Digest) (digest.Digest, error) {
+	v1Image.ID = ""
+	v1JSON, err := json.Marshal(v1Image)
+	if err != nil {
+		return "", err
+	}
+
+	var config map[string]*json.RawMessage
+	if err := json.Unmarshal(v1JSON, &config); err != nil {
+		return "", err
+	}
+
+	// FIXME: note that this is slightly incompatible with RootFS logic
+	config["layer_id"] = rawJSON(layerID)
+	if parent != "" {
+		config["parent"] = rawJSON(parent)
+	}
+
+	configJSON, err := json.Marshal(config)
+	if err != nil {
+		return "", err
+	}
+	logrus.Debugf("CreateV1ID %s", configJSON)
+
+	return digest.FromBytes(configJSON), nil
+}
+
+// MakeConfigFromV1Config creates an image config from the legacy V1 config format.
+func MakeConfigFromV1Config(imageJSON []byte, rootfs *image.RootFS, history []image.History) ([]byte, error) {
+	var dver struct {
+		DockerVersion string `json:"docker_version"`
+	}
+
+	if err := json.Unmarshal(imageJSON, &dver); err != nil {
+		return nil, err
+	}
+
+	useFallback := versions.LessThan(dver.DockerVersion, noFallbackMinVersion)
+
+	if useFallback {
+		var v1Image image.V1Image
+		err := json.Unmarshal(imageJSON, &v1Image)
+		if err != nil {
+			return nil, err
+		}
+		imageJSON, err = json.Marshal(v1Image)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	var c map[string]*json.RawMessage
+	if err := json.Unmarshal(imageJSON, &c); err != nil {
+		return nil, err
+	}
+
+	delete(c, "id")
+	delete(c, "parent")
+	delete(c, "Size") // Size is calculated from data on disk and is inconsistent
+	delete(c, "parent_id")
+	delete(c, "layer_id")
+	delete(c, "throwaway")
+
+	c["rootfs"] = rawJSON(rootfs)
+	c["history"] = rawJSON(history)
+
+	return json.Marshal(c)
+}
+
+// MakeV1ConfigFromConfig creates a legacy V1 image config from an Image struct
+func MakeV1ConfigFromConfig(img *image.Image, v1ID, parentV1ID string, throwaway bool) ([]byte, error) {
+	// Top-level v1compatibility string should be a modified version of the
+	// image config.
+	var configAsMap map[string]*json.RawMessage
+	if err := json.Unmarshal(img.RawJSON(), &configAsMap); err != nil {
+		return nil, err
+	}
+
+	// Delete fields that didn't exist in old manifest
+	imageType := reflect.TypeOf(img).Elem()
+	for i := 0; i < imageType.NumField(); i++ {
+		f := imageType.Field(i)
+		jsonName := strings.Split(f.Tag.Get("json"), ",")[0]
+		// Parent is handled specially below.
+		if jsonName != "" && jsonName != "parent" {
+			delete(configAsMap, jsonName)
+		}
+	}
+	configAsMap["id"] = rawJSON(v1ID)
+	if parentV1ID != "" {
+		configAsMap["parent"] = rawJSON(parentV1ID)
+	}
+	if throwaway {
+		configAsMap["throwaway"] = rawJSON(true)
+	}
+
+	return json.Marshal(configAsMap)
+}
+
+func rawJSON(value interface{}) *json.RawMessage {
+	jsonval, err := json.Marshal(value)
+	if err != nil {
+		return nil
+	}
+	return (*json.RawMessage)(&jsonval)
+}
+
+// ValidateID checks whether an ID string is a valid image ID.
+func ValidateID(id string) error {
+	return stringid.ValidateID(id)
+}
diff --git a/image/v1/imagev1_test.go b/image/v1/imagev1_test.go
new file mode 100644
index 0000000..936c55e
--- /dev/null
+++ b/image/v1/imagev1_test.go
@@ -0,0 +1,55 @@
+package v1
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/docker/docker/image"
+)
+
+func TestMakeV1ConfigFromConfig(t *testing.T) {
+	img := &image.Image{
+		V1Image: image.V1Image{
+			ID:     "v2id",
+			Parent: "v2parent",
+			OS:     "os",
+		},
+		OSVersion: "osversion",
+		RootFS: &image.RootFS{
+			Type: "layers",
+		},
+	}
+	v2js, err := json.Marshal(img)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Convert the image back in order to get RawJSON() support.
+	img, err = image.NewFromJSON(v2js)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	js, err := MakeV1ConfigFromConfig(img, "v1id", "v1parent", false)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	newimg := &image.Image{}
+	err = json.Unmarshal(js, newimg)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if newimg.V1Image.ID != "v1id" || newimg.Parent != "v1parent" {
+		t.Error("ids should have changed", newimg.V1Image.ID, newimg.V1Image.Parent)
+	}
+
+	if newimg.RootFS != nil {
+		t.Error("rootfs should have been removed")
+	}
+
+	if newimg.V1Image.OS != "os" {
+		t.Error("os should have been preserved")
+	}
+}