DockerCLI/cli/compose/loader/volume.go

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package loader
import (
"strings"
"unicode"
"unicode/utf8"
"github.com/docker/cli/cli/compose/types"
"github.com/docker/docker/api/types/mount"
"github.com/pkg/errors"
)
const endOfSpec = rune(0)
// ParseVolume parses a volume spec without any knowledge of the target platform
func ParseVolume(spec string) (types.ServiceVolumeConfig, error) {
volume := types.ServiceVolumeConfig{}
switch len(spec) {
case 0:
return volume, errors.New("invalid empty volume spec")
case 1, 2:
volume.Target = spec
volume.Type = string(mount.TypeVolume)
return volume, nil
}
buffer := []rune{}
for _, char := range spec + string(endOfSpec) {
switch {
case isWindowsDrive(buffer, char):
buffer = append(buffer, char)
case char == ':' || char == endOfSpec:
if err := populateFieldFromBuffer(char, buffer, &volume); err != nil {
populateType(&volume)
return volume, errors.Wrapf(err, "invalid spec: %s", spec)
}
buffer = []rune{}
default:
buffer = append(buffer, char)
}
}
populateType(&volume)
return volume, nil
}
func isWindowsDrive(buffer []rune, char rune) bool {
return char == ':' && len(buffer) == 1 && unicode.IsLetter(buffer[0])
}
func populateFieldFromBuffer(char rune, buffer []rune, volume *types.ServiceVolumeConfig) error {
strBuffer := string(buffer)
switch {
case len(buffer) == 0:
return errors.New("empty section between colons")
// Anonymous volume
case volume.Source == "" && char == endOfSpec:
volume.Target = strBuffer
return nil
case volume.Source == "":
volume.Source = strBuffer
return nil
case volume.Target == "":
volume.Target = strBuffer
return nil
case char == ':':
return errors.New("too many colons")
}
for _, option := range strings.Split(strBuffer, ",") {
switch option {
case "ro":
volume.ReadOnly = true
case "rw":
volume.ReadOnly = false
case "nocopy":
volume.Volume = &types.ServiceVolumeVolume{NoCopy: true}
default:
if isBindOption(option) {
volume.Bind = &types.ServiceVolumeBind{Propagation: option}
}
// ignore unknown options
}
}
return nil
}
func isBindOption(option string) bool {
for _, propagation := range mount.Propagations {
if mount.Propagation(option) == propagation {
return true
}
}
return false
}
func populateType(volume *types.ServiceVolumeConfig) {
switch {
// Anonymous volume
case volume.Source == "":
volume.Type = string(mount.TypeVolume)
case isFilePath(volume.Source):
volume.Type = string(mount.TypeBind)
default:
volume.Type = string(mount.TypeVolume)
}
}
func isFilePath(source string) bool {
switch source[0] {
case '.', '/', '~':
return true
}
// windows named pipes
if strings.HasPrefix(source, `\\`) {
return true
}
first, nextIndex := utf8.DecodeRuneInString(source)
return isWindowsDrive([]rune{first}, rune(source[nextIndex]))
}