package layer // import "github.com/docker/docker/layer"

 import (
 	"errors"
 )
 
 // Getter is an interface to get the path to a layer on the host.
 type Getter interface {
 	// GetLayerPath gets the path for the layer. This is different from Get()

 	// since that returns an interface to account for unmountable layers.

 	GetLayerPath(id string) (string, error)
 }

 
 // GetLayerPath returns the path to a layer
 func GetLayerPath(s Store, layer ChainID) (string, error) {
 	ls, ok := s.(*layerStore)
 	if !ok {
 		return "", errors.New("unsupported layer store")
 	}
 	ls.layerL.Lock()
 	defer ls.layerL.Unlock()
 
 	rl, ok := ls.layerMap[layer]
 	if !ok {
 		return "", ErrLayerDoesNotExist
 	}
 

 	if layerGetter, ok := ls.driver.(Getter); ok {

 		return layerGetter.GetLayerPath(rl.cacheID)
 	}

 	path, err := ls.driver.Get(rl.cacheID, "")

 	if err != nil {
 		return "", err
 	}
 

 	if err := ls.driver.Put(rl.cacheID); err != nil {

 		return "", err
 	}
 

 	return path.Path(), nil

 }
 

 func (ls *layerStore) mountID(name string) string {
 	// windows has issues if container ID doesn't match mount ID
 	return name
 }