Golang Info.DataDir方法代码示例

// basicEnv returns the app-level environment variables for a snap.
// Despite this being a bit snap-specific, this is in helpers.go because it's
// used by so many other modules, we run into circular dependencies if it's
// somewhere more reasonable like the snappy module.
func basicEnv(info *snap.Info) map[string]string {
	return map[string]string{
		"SNAP":              info.MountDir(),
		"SNAP_COMMON":       info.CommonDataDir(),
		"SNAP_DATA":         info.DataDir(),
		"SNAP_NAME":         info.Name(),
		"SNAP_VERSION":      info.Version,
		"SNAP_REVISION":     info.Revision.String(),
		"SNAP_ARCH":         arch.UbuntuArchitecture(),
		"SNAP_LIBRARY_PATH": "/var/lib/snapd/lib/gl:",
		"SNAP_REEXEC":       os.Getenv("SNAP_REEXEC"),
	}
}

// resolveSpecialVariable resolves one of the three $SNAP* variables at the
// beginning of a given path.  The variables are $SNAP, $SNAP_DATA and
// $SNAP_COMMON. If there are no variables then $SNAP is implicitly assumed
// (this is the behavior that was used before the variables were supporter).
func resolveSpecialVariable(path string, snapInfo *snap.Info) string {
	if strings.HasPrefix(path, "$SNAP/") || path == "$SNAP" {
		return strings.Replace(path, "$SNAP", snapInfo.MountDir(), 1)
	}
	if strings.HasPrefix(path, "$SNAP_DATA/") || path == "$SNAP_DATA" {
		return strings.Replace(path, "$SNAP_DATA", snapInfo.DataDir(), 1)
	}
	if strings.HasPrefix(path, "$SNAP_COMMON/") || path == "$SNAP_COMMON" {
		return strings.Replace(path, "$SNAP_COMMON", snapInfo.CommonDataDir(), 1)
	}
	// NOTE: assume $SNAP by default if nothing else is provided, for compatibility
	return filepath.Join(snapInfo.MountDir(), path)
}

// CopySnapData makes a copy of oldSnap data for newSnap in its data directories.
func (b Backend) CopySnapData(newSnap, oldSnap *snap.Info, meter progress.Meter) error {
	// deal with the old data or
	// otherwise just create a empty data dir

	// Make sure the common data directory exists, even if this isn't a new
	// install.
	if err := os.MkdirAll(newSnap.CommonDataDir(), 0755); err != nil {
		return err
	}

	if oldSnap == nil {
		return os.MkdirAll(newSnap.DataDir(), 0755)
	}

	return copySnapData(oldSnap, newSnap)
}

// Copy all data for oldSnap to newSnap
// (but never overwrite)
func copySnapData(oldSnap, newSnap *snap.Info) (err error) {
	oldDataDirs, err := snapDataDirs(oldSnap)
	if err != nil {
		return err
	}

	newSuffix := filepath.Base(newSnap.DataDir())
	for _, oldDir := range oldDataDirs {
		// replace the trailing "../$old-suffix" with the "../$new-suffix"
		newDir := filepath.Join(filepath.Dir(oldDir), newSuffix)
		if err := copySnapDataDirectory(oldDir, newDir); err != nil {
			return err
		}
	}

	return nil
}

// snapDataDirs returns the list of data directories for the given snap version
func snapDataDirs(snap *snap.Info) ([]string, error) {
	// collect the directories, homes first
	found, err := filepath.Glob(snap.DataHomeDir())
	if err != nil {
		return nil, err
	}
	// then system data
	found = append(found, snap.DataDir())

	return found, nil
}

func updateCurrentSymlinks(info *snap.Info) error {
	mountDir := info.MountDir()

	currentActiveSymlink := filepath.Join(mountDir, "..", "current")
	if err := os.Remove(currentActiveSymlink); err != nil && !os.IsNotExist(err) {
		logger.Noticef("Cannot remove %q: %v", currentActiveSymlink, err)
	}

	dataDir := info.DataDir()
	currentDataSymlink := filepath.Join(dataDir, "..", "current")
	if err := os.Remove(currentDataSymlink); err != nil && !os.IsNotExist(err) {
		logger.Noticef("Cannot remove %q: %v", currentDataSymlink, err)
	}

	if err := os.MkdirAll(info.DataDir(), 0755); err != nil {
		return err
	}

	if err := os.Symlink(filepath.Base(dataDir), currentDataSymlink); err != nil {
		return err
	}

	return os.Symlink(filepath.Base(mountDir), currentActiveSymlink)
}