layer

type ChainID digest.Digest

type CreateRWLayerOpts struct {
	MountLabel string
	InitFunc   MountInit
	StorageOpt map[string]string
}

type DescribableStore interface {
	RegisterWithDescriptor(io.Reader, ChainID, distribution.Descriptor) (Layer, error)
}

type DiffID digest.Digest

type Layer interface {
	TarStreamer

	// TarStreamFrom returns a tar archive stream for all the layer chain with
	// arbitrary depth.
	TarStreamFrom(ChainID) (io.ReadCloser, error)

	// ChainID returns the content hash of the entire layer chain. The hash
	// chain is made up of DiffID of top layer and all of its parents.
	ChainID() ChainID

	// DiffID returns the content hash of the layer
	// tar stream used to create this layer.
	DiffID() DiffID

	// Parent returns the next layer in the layer chain.
	Parent() Layer

	// Size returns the size of the entire layer chain. The size
	// is calculated from the total size of all files in the layers.
	Size() (int64, error)

	// DiffSize returns the size difference of the top layer
	// from parent layer.
	DiffSize() (int64, error)

	// Metadata returns the low level storage metadata associated
	// with layer.
	Metadata() (map[string]string, error)
}

type Metadata struct {
	// ChainID is the content hash of the layer
	ChainID ChainID

	// DiffID is the hash of the tar data used to
	// create the layer
	DiffID DiffID

	// Size is the size of the layer and all parents
	Size int64

	// DiffSize is the size of the top layer
	DiffSize int64
}

type MountInit func(root containerfs.ContainerFS) error

type RWLayer interface {
	TarStreamer

	// Name of mounted layer
	Name() string

	// Parent returns the layer which the writable
	// layer was created from.
	Parent() Layer

	// Mount mounts the RWLayer and returns the filesystem path
	// the to the writable layer.
	Mount(mountLabel string) (containerfs.ContainerFS, error)

	// Unmount unmounts the RWLayer. This should be called
	// for every mount. If there are multiple mount calls
	// this operation will only decrement the internal mount counter.
	Unmount() error

	// Size represents the size of the writable layer
	// as calculated by the total size of the files
	// changed in the mutable layer.
	Size() (int64, error)

	// Changes returns the set of changes for the mutable layer
	// from the base layer.
	Changes() ([]archive.Change, error)

	// Metadata returns the low level metadata for the mutable layer
	Metadata() (map[string]string, error)

	// ApplyDiff applies the diff to the RW layer
	ApplyDiff(diff io.Reader) (int64, error)
}

type Store interface {
	Register(io.Reader, ChainID) (Layer, error)
	Get(ChainID) (Layer, error)
	Map() map[ChainID]Layer
	Release(Layer) ([]Metadata, error)

	CreateRWLayer(id string, parent ChainID, opts *CreateRWLayerOpts) (RWLayer, error)
	GetRWLayer(id string) (RWLayer, error)
	GetMountID(id string) (string, error)
	ReleaseRWLayer(RWLayer) ([]Metadata, error)

	Cleanup() error
	DriverStatus() [][2]string
	DriverName() string
}

type StoreOptions struct {
	Root                      string
	MetadataStorePathTemplate string
	GraphDriver               string
	GraphDriverOptions        []string
	IDMapping                 *idtools.IdentityMapping
	PluginGetter              plugingetter.PluginGetter
	ExperimentalEnabled       bool
	OS                        string
}

type TarStreamer interface {
	// TarStream returns a tar archive stream
	// for the contents of a layer.
	TarStream() (io.ReadCloser, error)
}