1 files changed, 220 insertions, 0 deletions
diff --git a/image/image.go b/image/image.go
new file mode 100644
index 0000000..ab95d93
--- /dev/null
+++ b/image/image.go
@@ -0,0 +1,220 @@
+package image
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"runtime"
+	"strings"
+	"time"
+
+	"github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/dockerversion"
+	"github.com/docker/docker/layer"
+	"github.com/opencontainers/go-digest"
+)
+
+// ID is the content-addressable ID of an image.
+type ID digest.Digest
+
+func (id ID) String() string {
+	return id.Digest().String()
+}
+
+// Digest converts ID into a digest
+func (id ID) Digest() digest.Digest {
+	return digest.Digest(id)
+}
+
+// IDFromDigest creates an ID from a digest
+func IDFromDigest(digest digest.Digest) ID {
+	return ID(digest)
+}
+
+// V1Image stores the V1 image configuration.
+type V1Image struct {
+	// ID is a unique 64 character identifier of the image
+	ID string `json:"id,omitempty"`
+	// Parent is the ID of the parent image
+	Parent string `json:"parent,omitempty"`
+	// Comment is the commit message that was set when committing the image
+	Comment string `json:"comment,omitempty"`
+	// Created is the timestamp at which the image was created
+	Created time.Time `json:"created"`
+	// Container is the id of the container used to commit
+	Container string `json:"container,omitempty"`
+	// ContainerConfig is the configuration of the container that is committed into the image
+	ContainerConfig container.Config `json:"container_config,omitempty"`
+	// DockerVersion specifies the version of Docker that was used to build the image
+	DockerVersion string `json:"docker_version,omitempty"`
+	// Author is the name of the author that was specified when committing the image
+	Author string `json:"author,omitempty"`
+	// Config is the configuration of the container received from the client
+	Config *container.Config `json:"config,omitempty"`
+	// Architecture is the hardware that the image is built and runs on
+	Architecture string `json:"architecture,omitempty"`
+	// OS is the operating system used to build and run the image
+	OS string `json:"os,omitempty"`
+	// Size is the total size of the image including all layers it is composed of
+	Size int64 `json:",omitempty"`
+}
+
+// Image stores the image configuration
+type Image struct {
+	V1Image
+	Parent     ID        `json:"parent,omitempty"`
+	RootFS     *RootFS   `json:"rootfs,omitempty"`
+	History    []History `json:"history,omitempty"`
+	OSVersion  string    `json:"os.version,omitempty"`
+	OSFeatures []string  `json:"os.features,omitempty"`
+
+	// rawJSON caches the immutable JSON associated with this image.
+	rawJSON []byte
+
+	// computedID is the ID computed from the hash of the image config.
+	// Not to be confused with the legacy V1 ID in V1Image.
+	computedID ID
+}
+
+// RawJSON returns the immutable JSON associated with the image.
+func (img *Image) RawJSON() []byte {
+	return img.rawJSON
+}
+
+// ID returns the image's content-addressable ID.
+func (img *Image) ID() ID {
+	return img.computedID
+}
+
+// ImageID stringifies ID.
+func (img *Image) ImageID() string {
+	return img.ID().String()
+}
+
+// RunConfig returns the image's container config.
+func (img *Image) RunConfig() *container.Config {
+	return img.Config
+}
+
+// Platform returns the image's operating system. If not populated, defaults to the host runtime OS.
+func (img *Image) Platform() string {
+	os := img.OS
+	if os == "" {
+		os = runtime.GOOS
+	}
+	return os
+}
+
+// MarshalJSON serializes the image to JSON. It sorts the top-level keys so
+// that JSON that's been manipulated by a push/pull cycle with a legacy
+// registry won't end up with a different key order.
+func (img *Image) MarshalJSON() ([]byte, error) {
+	type MarshalImage Image
+
+	pass1, err := json.Marshal(MarshalImage(*img))
+	if err != nil {
+		return nil, err
+	}
+
+	var c map[string]*json.RawMessage
+	if err := json.Unmarshal(pass1, &c); err != nil {
+		return nil, err
+	}
+	return json.Marshal(c)
+}
+
+// ChildConfig is the configuration to apply to an Image to create a new
+// Child image. Other properties of the image are copied from the parent.
+type ChildConfig struct {
+	ContainerID     string
+	Author          string
+	Comment         string
+	DiffID          layer.DiffID
+	ContainerConfig *container.Config
+	Config          *container.Config
+}
+
+// NewChildImage creates a new Image as a child of this image.
+func NewChildImage(img *Image, child ChildConfig, platform string) *Image {
+	isEmptyLayer := layer.IsEmpty(child.DiffID)
+	rootFS := img.RootFS
+	if rootFS == nil {
+		rootFS = NewRootFS()
+	}
+	if !isEmptyLayer {
+		rootFS.Append(child.DiffID)
+	}
+	imgHistory := NewHistory(
+		child.Author,
+		child.Comment,
+		strings.Join(child.ContainerConfig.Cmd, " "),
+		isEmptyLayer)
+
+	return &Image{
+		V1Image: V1Image{
+			DockerVersion:   dockerversion.Version,
+			Config:          child.Config,
+			Architecture:    runtime.GOARCH,
+			OS:              platform,
+			Container:       child.ContainerID,
+			ContainerConfig: *child.ContainerConfig,
+			Author:          child.Author,
+			Created:         imgHistory.Created,
+		},
+		RootFS:     rootFS,
+		History:    append(img.History, imgHistory),
+		OSFeatures: img.OSFeatures,
+		OSVersion:  img.OSVersion,
+	}
+}
+
+// History stores build commands that were used to create an image
+type History struct {
+	// Created is the timestamp at which the image was created
+	Created time.Time `json:"created"`
+	// Author is the name of the author that was specified when committing the image
+	Author string `json:"author,omitempty"`
+	// CreatedBy keeps the Dockerfile command used while building the image
+	CreatedBy string `json:"created_by,omitempty"`
+	// Comment is the commit message that was set when committing the image
+	Comment string `json:"comment,omitempty"`
+	// EmptyLayer is set to true if this history item did not generate a
+	// layer. Otherwise, the history item is associated with the next
+	// layer in the RootFS section.
+	EmptyLayer bool `json:"empty_layer,omitempty"`
+}
+
+// NewHistory creates a new history struct from arguments, and sets the created
+// time to the current time in UTC
+func NewHistory(author, comment, createdBy string, isEmptyLayer bool) History {
+	return History{
+		Author:     author,
+		Created:    time.Now().UTC(),
+		CreatedBy:  createdBy,
+		Comment:    comment,
+		EmptyLayer: isEmptyLayer,
+	}
+}
+
+// Exporter provides interface for loading and saving images
+type Exporter interface {
+	Load(io.ReadCloser, io.Writer, bool) error
+	// TODO: Load(net.Context, io.ReadCloser, <- chan StatusMessage) error
+	Save([]string, io.Writer) error
+}
+
+// NewFromJSON creates an Image configuration from json.
+func NewFromJSON(src []byte) (*Image, error) {
+	img := &Image{}
+
+	if err := json.Unmarshal(src, img); err != nil {
+		return nil, err
+	}
+	if img.RootFS == nil {
+		return nil, errors.New("invalid image JSON, no RootFS key")
+	}
+
+	img.rawJSON = src
+
+	return img, nil
+}