package image // import "github.com/docker/docker/image" import ( "runtime" "github.com/docker/docker/layer" "github.com/sirupsen/logrus" ) // TypeLayers is used for RootFS.Type for filesystems organized into layers. const TypeLayers = "layers" // typeLayersWithBase is an older format used by Windows up to v1.12. We // explicitly handle this as an error case to ensure that a daemon which still // has an older image like this on disk can still start, even though the // image itself is not usable. See https://github.com/docker/docker/pull/25806. const typeLayersWithBase = "layers+base" // RootFS describes images root filesystem // This is currently a placeholder that only supports layers. In the future // this can be made into an interface that supports different implementations. type RootFS struct { Type string `json:"type"` DiffIDs []layer.DiffID `json:"diff_ids,omitempty"` } // NewRootFS returns empty RootFS struct func NewRootFS() *RootFS { return &RootFS{Type: TypeLayers} } // Append appends a new diffID to rootfs func (r *RootFS) Append(id layer.DiffID) { r.DiffIDs = append(r.DiffIDs, id) } // Clone returns a copy of the RootFS func (r *RootFS) Clone() *RootFS { newRoot := NewRootFS() newRoot.Type = r.Type newRoot.DiffIDs = append(r.DiffIDs) return newRoot } // ChainID returns the ChainID for the top layer in RootFS. func (r *RootFS) ChainID() layer.ChainID { if runtime.GOOS == "windows" && r.Type == typeLayersWithBase { logrus.Warnf("Layer type is unsupported on this platform. DiffIDs: '%v'", r.DiffIDs) return "" } return layer.CreateChainID(r.DiffIDs) }