Support: Add PathV2 implementation.

llvm-svn: 120329

1 files changed, 71 insertions, 0 deletions

diff --git a/llvm/lib/Support/Windows/PathV2.inc b/llvm/lib/Support/Windows/PathV2.inc
new file mode 100644
index 00000000000..9c15e26b79d
--- /dev/null
+++ b/llvm/lib/Support/Windows/PathV2.inc
@@ -0,0 +1,71 @@
+//===- llvm/Support/Win32/PathV2.cpp - Windows Path Impl --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Windows specific implementation of the PathV2 API.
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only generic Windows code that
+//===          is guaranteed to work on *all* Windows variants.
+//===----------------------------------------------------------------------===//
+
+#include "Windows.h"
+
+namespace llvm {
+namespace sys  {
+namespace path {
+
+error_code current_path(SmallVectorImpl<char> &result) {
+  SmallVector<wchar_t, 128> cur_path;
+  cur_path.reserve(128);
+retry_cur_dir:
+  DWORD len = ::GetCurrentDirectoryW(cur_path.capacity(), cur_path.data());
+
+  // A zero return value indicates a failure other than insufficient space.
+  if (len == 0)
+    return make_error_code(windows_error(::GetLastError()));
+
+  // If there's insufficient space, the len returned is larger than the len
+  // given.
+  if (len > cur_path.capacity()) {
+    cur_path.reserve(len);
+    goto retry_cur_dir;
+  }
+
+  cur_path.set_size(len);
+  // cur_path now holds the current directory in utf-16. Convert to utf-8.
+
+  // Find out how much space we need. Sadly, this function doesn't return the
+  // size needed unless you tell it the result size is 0, which means you
+  // _always_ have to call it twice.
+  len = ::WideCharToMultiByte(CP_UTF8, NULL,
+                              cur_path.data(), cur_path.size(),
+                              result.data(), 0,
+                              NULL, NULL);
+
+  if (len == 0)
+    return make_error_code(windows_error(::GetLastError()));
+
+  result.reserve(len);
+  result.set_size(len);
+  // Now do the actual conversion.
+  len = ::WideCharToMultiByte(CP_UTF8, NULL,
+                              cur_path.data(), cur_path.size(),
+                              result.data(), result.size(),
+                              NULL, NULL);
+  if (len == 0)
+    return make_error_code(windows_error(::GetLastError()));
+
+  return make_error_code(errc::success);
+}
+
+} // end namespace path
+} // end namespace sys
+} // end namespace llvm