1 files changed, 68 insertions, 0 deletions
diff --git a/vendor/github.com/Microsoft/hcsshim/internal/wclayer/exportlayer.go b/vendor/github.com/Microsoft/hcsshim/internal/wclayer/exportlayer.go
new file mode 100644
index 000000000..d43e941ee
--- /dev/null
+++ b/vendor/github.com/Microsoft/hcsshim/internal/wclayer/exportlayer.go
@@ -0,0 +1,68 @@
+package wclayer
+
+import (
+	"io/ioutil"
+	"os"
+
+	"github.com/Microsoft/go-winio"
+	"github.com/Microsoft/hcsshim/internal/hcserror"
+	"github.com/sirupsen/logrus"
+)
+
+// ExportLayer will create a folder at exportFolderPath and fill that folder with
+// the transport format version of the layer identified by layerId. This transport
+// format includes any metadata required for later importing the layer (using
+// ImportLayer), and requires the full list of parent layer paths in order to
+// perform the export.
+func ExportLayer(path string, exportFolderPath string, parentLayerPaths []string) error {
+	title := "hcsshim::ExportLayer "
+	logrus.Debugf(title+"path %s folder %s", path, exportFolderPath)
+
+	// Generate layer descriptors
+	layers, err := layerPathsToDescriptors(parentLayerPaths)
+	if err != nil {
+		return err
+	}
+
+	err = exportLayer(&stdDriverInfo, path, exportFolderPath, layers)
+	if err != nil {
+		err = hcserror.Errorf(err, title, "path=%s folder=%s", path, exportFolderPath)
+		logrus.Error(err)
+		return err
+	}
+
+	logrus.Debugf(title+"succeeded path=%s folder=%s", path, exportFolderPath)
+	return nil
+}
+
+type LayerReader interface {
+	Next() (string, int64, *winio.FileBasicInfo, error)
+	Read(b []byte) (int, error)
+	Close() error
+}
+
+// NewLayerReader returns a new layer reader for reading the contents of an on-disk layer.
+// The caller must have taken the SeBackupPrivilege privilege
+// to call this and any methods on the resulting LayerReader.
+func NewLayerReader(path string, parentLayerPaths []string) (LayerReader, error) {
+	exportPath, err := ioutil.TempDir("", "hcs")
+	if err != nil {
+		return nil, err
+	}
+	err = ExportLayer(path, exportPath, parentLayerPaths)
+	if err != nil {
+		os.RemoveAll(exportPath)
+		return nil, err
+	}
+	return &legacyLayerReaderWrapper{newLegacyLayerReader(exportPath)}, nil
+}
+
+type legacyLayerReaderWrapper struct {
+	*legacyLayerReader
+}
+
+func (r *legacyLayerReaderWrapper) Close() error {
+	err := r.legacyLayerReader.Close()
+	os.RemoveAll(r.root)
+	return err
+}