//===- 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