mfbt/FStream.h
author Narcis Beleuzu <nbeleuzu@mozilla.com>
Thu, 21 Jun 2018 16:51:55 +0300
changeset 477502 59322b179c0fdb4423d42b624da7bf64ee5a2327
parent 458200 c88a04f0291b81c7771735f25b52e72e544b726f
child 478859 23fb443b22143c059267eb254ddd4b2e9fcc4e41
permissions -rw-r--r--
Backed out 4 changesets (bug 1268889) for Windows GTest failures. CLOSED TREE Backed out changeset da427a67372e (bug 1268889) Backed out changeset 97528847b7b7 (bug 1268889) Backed out changeset b2320061fbcb (bug 1268889) Backed out changeset dd3b7047ea6f (bug 1268889)

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

// Similar to std::ifstream/ofstream, but takes char16ptr_t on Windows.
// Until C++17, std functions can only take char* filenames. So Unicode
// filenames were lost on Windows. To address this limitations, this wrapper
// uses proprietary wchar_t* overloads on MSVC, and __gnu_cxx::stdio_filebuf
// extension on MinGW. Once we can use C++17 filesystem API everywhere,
// we will be able to avoid this wrapper.

#ifndef mozilla_FStream_h
#define mozilla_FStream_h

#include "mozilla/Char16.h"
#include <istream>
#include <ostream>
#include <fstream>
#if defined(__MINGW32__)
#include "mozilla/UniquePtr.h"
#include <fcntl.h>
#include <ext/stdio_filebuf.h>
#endif

namespace mozilla {

#if defined(__MINGW32__)
// MinGW does not support wchar_t* overloads that are MSVC extension until
// C++17, so we have to implement widechar wrappers using a GNU extension.
class IFStream : public std::istream
{
public:
  explicit IFStream(char16ptr_t filename, openmode mode = in);

  std::filebuf* rdbuf() const { return mFileBuf.get(); }

  bool is_open() const { return mFileBuf && mFileBuf->is_open(); }
  void open(char16ptr_t filename, openmode mode = in);
  void close() { mFileBuf && mFileBuf->close(); }

private:
  UniquePtr<std::filebuf> mFileBuf;
};

inline
IFStream::IFStream(char16ptr_t filename, openmode mode)
  : std::istream(nullptr)
{
  open(filename, mode);
}

inline void
IFStream::open(char16ptr_t filename, openmode mode)
{
  int fmode = _O_RDONLY;
  if (mode & binary) {
    fmode |= _O_BINARY;
  } else {
    fmode |= _O_TEXT;
  }
  int fd = _wopen(filename, fmode);
  mFileBuf = MakeUnique<__gnu_cxx::stdio_filebuf<char>>(fd, mode);
  std::istream::rdbuf(mFileBuf.get());
}

class OFStream : public std::ostream
{
public:
  explicit OFStream(char16ptr_t filename, openmode mode = out);

  std::filebuf* rdbuf() const { return mFileBuf.get(); }

  bool is_open() const { return mFileBuf && mFileBuf->is_open(); }
  void open(char16ptr_t filename, openmode mode = out);
  void close() { mFileBuf && mFileBuf->close(); }

private:
  UniquePtr<std::filebuf> mFileBuf;
};

inline
OFStream::OFStream(char16ptr_t filename, openmode mode)
  : std::ostream(nullptr)
{
  open(filename, mode);
}

inline void
OFStream::open(char16ptr_t filename, openmode mode)
{
  int fmode = _O_WRONLY;
  if (mode & binary) {
    fmode |= _O_BINARY;
  } else {
    fmode |= _O_TEXT;
  }
  if (mode & trunc) {
    fmode |= _O_CREAT | _O_TRUNC;
  }
  int fd = _wopen(filename, fmode);
  mFileBuf = MakeUnique<__gnu_cxx::stdio_filebuf<char>>(fd, mode);
  std::ostream::rdbuf(mFileBuf.get());
}

#elif defined(XP_WIN)
class IFStream : public std::ifstream
{
public:
  explicit IFStream(char16ptr_t filename, openmode mode = in)
    : std::ifstream(filename, mode) {}

  void open(char16ptr_t filename, openmode mode = in)
  {
    std::ifstream::open(filename, mode);
  }
};

class OFStream : public std::ofstream
{
public:
  explicit OFStream(char16ptr_t filename, openmode mode = out)
    : std::ofstream(filename, mode) {}

  void open(char16ptr_t filename, openmode mode = out)
  {
    std::ofstream::open(filename, mode);
  }
};
#else
using IFStream = std::ifstream;
using OFStream = std::ofstream;
#endif

} // namespace mozilla

#endif /* mozilla_FStream_h */