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moby--moby/layer/ro_layer.go

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package layer
import "io"
type roLayer struct {
chainID ChainID
diffID DiffID
parent *roLayer
cacheID string
size int64
layerStore *layerStore
referenceCount int
references map[Layer]struct{}
}
func (rl *roLayer) TarStream() (io.ReadCloser, error) {
r, err := rl.layerStore.store.TarSplitReader(rl.chainID)
if err != nil {
return nil, err
}
pr, pw := io.Pipe()
go func() {
err := rl.layerStore.assembleTarTo(rl.cacheID, r, nil, pw)
if err != nil {
pw.CloseWithError(err)
} else {
pw.Close()
}
}()
return pr, nil
}
func (rl *roLayer) ChainID() ChainID {
return rl.chainID
}
func (rl *roLayer) DiffID() DiffID {
return rl.diffID
}
func (rl *roLayer) Parent() Layer {
if rl.parent == nil {
return nil
}
return rl.parent
}
func (rl *roLayer) Size() (size int64, err error) {
if rl.parent != nil {
size, err = rl.parent.Size()
if err != nil {
return
}
}
return size + rl.size, nil
}
func (rl *roLayer) DiffSize() (size int64, err error) {
return rl.size, nil
}
func (rl *roLayer) Metadata() (map[string]string, error) {
return rl.layerStore.driver.GetMetadata(rl.cacheID)
}
type referencedCacheLayer struct {
*roLayer
}
func (rl *roLayer) getReference() Layer {
ref := &referencedCacheLayer{
roLayer: rl,
}
rl.references[ref] = struct{}{}
return ref
}
func (rl *roLayer) hasReference(ref Layer) bool {
_, ok := rl.references[ref]
return ok
}
func (rl *roLayer) hasReferences() bool {
return len(rl.references) > 0
}
func (rl *roLayer) deleteReference(ref Layer) {
delete(rl.references, ref)
}
func (rl *roLayer) depth() int {
if rl.parent == nil {
return 1
}
return rl.parent.depth() + 1
}
func storeLayer(tx MetadataTransaction, layer *roLayer) error {
if err := tx.SetDiffID(layer.diffID); err != nil {
return err
}
if err := tx.SetSize(layer.size); err != nil {
return err
}
if err := tx.SetCacheID(layer.cacheID); err != nil {
return err
}
if layer.parent != nil {
if err := tx.SetParent(layer.parent.chainID); err != nil {
return err
}
}
return nil
}