Container changes (#320)

Added container metrics

vendor/github.com/Microsoft/hcsshim/internal/copyfile/copyfile.go

@@ -0,0 +1,40 @@
+package copyfile
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+)
+
+var (
+	modkernel32   = syscall.NewLazyDLL("kernel32.dll")
+	procCopyFileW = modkernel32.NewProc("CopyFileW")
+)
+
+// CopyFile is a utility for copying a file - used for the LCOW scratch cache.
+// Uses CopyFileW win32 API for performance.
+func CopyFile(srcFile, destFile string, overwrite bool) error {
+	var bFailIfExists uint32 = 1
+	if overwrite {
+		bFailIfExists = 0
+	}
+
+	lpExistingFileName, err := syscall.UTF16PtrFromString(srcFile)
+	if err != nil {
+		return err
+	}
+	lpNewFileName, err := syscall.UTF16PtrFromString(destFile)
+	if err != nil {
+		return err
+	}
+	r1, _, err := syscall.Syscall(
+		procCopyFileW.Addr(),
+		3,
+		uintptr(unsafe.Pointer(lpExistingFileName)),
+		uintptr(unsafe.Pointer(lpNewFileName)),
+		uintptr(bFailIfExists))
+	if r1 == 0 {
+		return fmt.Errorf("failed CopyFileW Win32 call from '%s' to '%s': %s", srcFile, destFile, err)
+	}
+	return nil
+}