package volume
 

 import (

 	"fmt"

 	"os"
 	"strings"

 	"syscall"

 
 	"github.com/docker/docker/pkg/stringid"

 	"github.com/docker/docker/pkg/system"

 	"github.com/opencontainers/runc/libcontainer/label"

 )
 

 // DefaultDriverName is the driver name used for the driver
 // implemented in the local package.

 const DefaultDriverName = "local"
 
 // Scopes define if a volume has is cluster-wide (global) or local only.
 // Scopes are returned by the volume driver when it is queried for capabilities and then set on a volume
 const (
 	LocalScope  = "local"
 	GlobalScope = "global"
 )

 // Driver is for creating and removing volumes.

 type Driver interface {
 	// Name returns the name of the volume driver.
 	Name() string
 	// Create makes a new volume with the given id.

 	Create(name string, opts map[string]string) (Volume, error)

 	// Remove deletes the volume.

 	Remove(vol Volume) (err error)
 	// List lists all the volumes the driver has
 	List() ([]Volume, error)

 	// Get retrieves the volume with the requested name

 	Get(name string) (Volume, error)

 	// Scope returns the scope of the driver (e.g. `golbal` or `local`).
 	// Scope determines how the driver is handled at a cluster level
 	Scope() string
 }
 
 // Capability defines a set of capabilities that a driver is able to handle.
 type Capability struct {
 	// Scope is the scope of the driver, `global` or `local`
 	// A `global` scope indicates that the driver manages volumes across the cluster
 	// A `local` scope indicates that the driver only manages volumes resources local to the host
 	// Scope is declared by the driver
 	Scope string

 }
 

 // Volume is a place to store data. It is backed by a specific driver, and can be mounted.

 type Volume interface {
 	// Name returns the name of the volume
 	Name() string
 	// DriverName returns the name of the driver which owns this volume.
 	DriverName() string
 	// Path returns the absolute path to the volume.
 	Path() string
 	// Mount mounts the volume and returns the absolute path to
 	// where it can be consumed.

 	Mount(id string) (string, error)

 	// Unmount unmounts the volume when it is no longer in use.

 	Unmount(id string) error

 	// Status returns low-level status information about a volume
 	Status() map[string]interface{}

 }

 // LabeledVolume wraps a Volume with user-defined labels
 type LabeledVolume interface {
 	Labels() map[string]string
 	Volume
 }
 
 // ScopedVolume wraps a volume with a cluster scope (e.g., `local` or `global`)
 type ScopedVolume interface {
 	Scope() string
 	Volume
 }
 

 // MountPoint is the intersection point between a volume and a container. It
 // specifies which volume is to be used and where inside a container it should
 // be mounted.
 type MountPoint struct {
 	Source      string // Container host directory
 	Destination string // Inside the container
 	RW          bool   // True if writable
 	Name        string // Name set by user
 	Driver      string // Volume driver to use
 	Volume      Volume `json:"-"`
 
 	// Note Mode is not used on Windows
 	Mode string `json:"Relabel"` // Originally field was `Relabel`"

 
 	// Note Propagation is not used on Windows
 	Propagation string // Mount propagation string

 	Named       bool   // specifies if the mountpoint was specified by name

 
 	// Specifies if data should be copied from the container before the first mount
 	// Use a pointer here so we can tell if the user set this value explicitly
 	// This allows us to error out when the user explicitly enabled copy but we can't copy due to the volume being populated
 	CopyData bool `json:"-"`

 	// ID is the opaque ID used to pass to the volume driver.
 	// This should be set by calls to `Mount` and unset by calls to `Unmount`
 	ID string

 }
 
 // Setup sets up a mount point by either mounting the volume if it is
 // configured, or creating the source directory if supplied.

 func (m *MountPoint) Setup(mountLabel string) (string, error) {

 	if m.Volume != nil {

 		if m.ID == "" {
 			m.ID = stringid.GenerateNonCryptoID()
 		}
 		return m.Volume.Mount(m.ID)

 	}

 	if len(m.Source) == 0 {
 		return "", fmt.Errorf("Unable to setup mount point, neither source nor volume defined")
 	}
 	// system.MkdirAll() produces an error if m.Source exists and is a file (not a directory),

 	if err := system.MkdirAll(m.Source, 0755); err != nil {
 		if perr, ok := err.(*os.PathError); ok {
 			if perr.Err != syscall.ENOTDIR {
 				return "", err
 			}

 		}

 	}
 	if label.RelabelNeeded(m.Mode) {
 		if err := label.Relabel(m.Source, mountLabel, label.IsShared(m.Mode)); err != nil {

 			return "", err

 		}
 	}

 	return m.Source, nil

 }
 

 // Path returns the path of a volume in a mount point.
 func (m *MountPoint) Path() string {
 	if m.Volume != nil {
 		return m.Volume.Path()
 	}
 	return m.Source

 }
 

 // Type returns the type of mount point
 func (m *MountPoint) Type() string {
 	if m.Name != "" {

 		return "volume"

 	}
 	if m.Source != "" {

 		return "bind"

 	}

 	return "ephemeral"

 }
 

 // ParseVolumesFrom ensures that the supplied volumes-from is valid.

 func ParseVolumesFrom(spec string) (string, string, error) {
 	if len(spec) == 0 {

 		return "", "", fmt.Errorf("malformed volumes-from specification: %s", spec)

 	}
 
 	specParts := strings.SplitN(spec, ":", 2)
 	id := specParts[0]
 	mode := "rw"
 
 	if len(specParts) == 2 {
 		mode = specParts[1]
 		if !ValidMountMode(mode) {

 			return "", "", errInvalidMode(mode)

 		}

 		// For now don't allow propagation properties while importing
 		// volumes from data container. These volumes will inherit
 		// the same propagation property as of the original volume
 		// in data container. This probably can be relaxed in future.
 		if HasPropagation(mode) {

 			return "", "", errInvalidMode(mode)

 		}

 		// Do not allow copy modes on volumes-from
 		if _, isSet := getCopyMode(mode); isSet {
 			return "", "", errInvalidMode(mode)
 		}

 	}
 	return id, mode, nil
 }

 
 func errInvalidMode(mode string) error {
 	return fmt.Errorf("invalid mode: %v", mode)
 }
 
 func errInvalidSpec(spec string) error {
 	return fmt.Errorf("Invalid volume specification: '%s'", spec)
 }