vendor: initial vendor

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/Microsoft/hcsshim/internal/wclayer/layerutils.go

@@ -0,0 +1,96 @@
+package wclayer
+
+// This file contains utility functions to support storage (graph) related
+// functionality.
+
+import (
+	"syscall"
+
+	"github.com/Microsoft/hcsshim/internal/guid"
+	"github.com/sirupsen/logrus"
+)
+
+/* To pass into syscall, we need a struct matching the following:
+enum GraphDriverType
+{
+    DiffDriver,
+    FilterDriver
+};
+
+struct DriverInfo {
+    GraphDriverType Flavour;
+    LPCWSTR HomeDir;
+};
+*/
+
+type driverInfo struct {
+	Flavour  int
+	HomeDirp *uint16
+}
+
+var (
+	utf16EmptyString uint16
+	stdDriverInfo    = driverInfo{1, &utf16EmptyString}
+)
+
+/* To pass into syscall, we need a struct matching the following:
+typedef struct _WC_LAYER_DESCRIPTOR {
+
+    //
+    // The ID of the layer
+    //
+
+    GUID LayerId;
+
+    //
+    // Additional flags
+    //
+
+    union {
+        struct {
+            ULONG Reserved : 31;
+            ULONG Dirty : 1;    // Created from sandbox as a result of snapshot
+        };
+        ULONG Value;
+    } Flags;
+
+    //
+    // Path to the layer root directory, null-terminated
+    //
+
+    PCWSTR Path;
+
+} WC_LAYER_DESCRIPTOR, *PWC_LAYER_DESCRIPTOR;
+*/
+type WC_LAYER_DESCRIPTOR struct {
+	LayerId guid.GUID
+	Flags   uint32
+	Pathp   *uint16
+}
+
+func layerPathsToDescriptors(parentLayerPaths []string) ([]WC_LAYER_DESCRIPTOR, error) {
+	// Array of descriptors that gets constructed.
+	var layers []WC_LAYER_DESCRIPTOR
+
+	for i := 0; i < len(parentLayerPaths); i++ {
+		g, err := LayerID(parentLayerPaths[i])
+		if err != nil {
+			logrus.WithError(err).Debug("Failed to convert name to guid")
+			return nil, err
+		}
+
+		p, err := syscall.UTF16PtrFromString(parentLayerPaths[i])
+		if err != nil {
+			logrus.WithError(err).Debug("Failed conversion of parentLayerPath to pointer")
+			return nil, err
+		}
+
+		layers = append(layers, WC_LAYER_DESCRIPTOR{
+			LayerId: g,
+			Flags:   0,
+			Pathp:   p,
+		})
+	}
+
+	return layers, nil
+}