Support/FileSystem: Add resize_file implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120819 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Windows/PathV2.inc b/lib/Support/Windows/PathV2.inc
index c97ba5d..e981507 100644
--- a/lib/Support/Windows/PathV2.inc
+++ b/lib/Support/Windows/PathV2.inc
@@ -18,7 +18,10 @@
 
 #include "Windows.h"
 #include <WinCrypt.h>
+#include <fcntl.h>
 #include <io.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 
 using namespace llvm;
 
@@ -290,6 +293,22 @@
   return make_error_code(errc::success);
 }
 
+error_code resize_file(const Twine &path, uint64_t size) {
+  SmallString<128> path_storage;
+  SmallVector<wchar_t, 128> path_utf16;
+
+  if (error_code ec = UTF8ToUTF16(path.toStringRef(path_storage),
+                                  path_utf16))
+    return ec;
+
+  int fd = ::_wopen(path_utf16.begin(), O_BINARY, S_IREAD | S_IWRITE);
+  if (fd == -1)
+    return error_code(errno, generic_category());
+  errno_t error = ::_chsize_s(fd, size);
+  ::close(fd);
+  return error_code(error, generic_category());
+}
+
 error_code exists(const Twine &path, bool &result) {
   SmallString<128> path_storage;
   SmallVector<wchar_t, 128> path_utf16;