mfbt/FStream.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 // Similar to std::ifstream/ofstream, but takes char16ptr_t on Windows.
   8 // Until C++17, std functions can only take char* filenames. So Unicode
   9 // filenames were lost on Windows. To address this limitations, this wrapper
  10 // uses proprietary wchar_t* overloads on MSVC, and __gnu_cxx::stdio_filebuf
  11 // extension on MinGW. Once we can use C++17 filesystem API everywhere,
  12 // we will be able to avoid this wrapper.
  13
  14 #ifndef mozilla_FStream_h
  15 #define mozilla_FStream_h
  16
  17 #include "mozilla/Char16.h"
  18 #include <istream>
  19 #include <ostream>
  20 #include <fstream>
  21 #if defined(__MINGW32__) && defined(__GLIBCXX__)
  22 #  include "mozilla/UniquePtr.h"
  23 #  include <fcntl.h>
  24 #  include <ext/stdio_filebuf.h>
  25 #endif
  26
  27 namespace mozilla {
  28
  29 #if defined(__MINGW32__) && defined(__GLIBCXX__)
  30 // MinGW does not support wchar_t* overloads that are MSVC extension until
  31 // C++17, so we have to implement widechar wrappers using a GNU extension.
  32 class IFStream : public std::istream {
  33  public:
  34   explicit IFStream(char16ptr_t filename, openmode mode = in);
  35
  36   std::filebuf* rdbuf() const { return mFileBuf.get(); }
  37
  38   bool is_open() const { return mFileBuf && mFileBuf->is_open(); }
  39   void open(char16ptr_t filename, openmode mode = in);
  40   void close() { mFileBuf && mFileBuf->close(); }
  41
  42  private:
  43   UniquePtr<std::filebuf> mFileBuf;
  44 };
  45
  46 inline IFStream::IFStream(char16ptr_t filename, openmode mode)
  47     : std::istream(nullptr) {
  48   open(filename, mode);
  49 }
  50
  51 inline void IFStream::open(char16ptr_t filename, openmode mode) {
  52   int fmode = _O_RDONLY;
  53   if (mode & binary) {
  54     fmode |= _O_BINARY;
  55   } else {
  56     fmode |= _O_TEXT;
  57   }
  58   int fd = _wopen(filename, fmode);
  59   mFileBuf = MakeUnique<__gnu_cxx::stdio_filebuf<char>>(fd, mode);
  60   std::istream::rdbuf(mFileBuf.get());
  61 }
  62
  63 class OFStream : public std::ostream {
  64  public:
  65   explicit OFStream(char16ptr_t filename, openmode mode = out);
  66
  67   std::filebuf* rdbuf() const { return mFileBuf.get(); }
  68
  69   bool is_open() const { return mFileBuf && mFileBuf->is_open(); }
  70   void open(char16ptr_t filename, openmode mode = out);
  71   void close() { mFileBuf && mFileBuf->close(); }
  72
  73  private:
  74   UniquePtr<std::filebuf> mFileBuf;
  75 };
  76
  77 inline OFStream::OFStream(char16ptr_t filename, openmode mode)
  78     : std::ostream(nullptr) {
  79   open(filename, mode);
  80 }
  81
  82 inline void OFStream::open(char16ptr_t filename, openmode mode) {
  83   int fmode = _O_WRONLY;
  84   if (mode & binary) {
  85     fmode |= _O_BINARY;
  86   } else {
  87     fmode |= _O_TEXT;
  88   }
  89   if (mode & trunc) {
  90     fmode |= _O_CREAT | _O_TRUNC;
  91   }
  92   int fd = _wopen(filename, fmode);
  93   mFileBuf = MakeUnique<__gnu_cxx::stdio_filebuf<char>>(fd, mode);
  94   std::ostream::rdbuf(mFileBuf.get());
  95 }
  96
  97 #elif defined(XP_WIN)
  98 class IFStream : public std::ifstream {
  99  public:
 100   explicit IFStream(char16ptr_t filename, openmode mode = in)
 101       : std::ifstream(filename, mode) {}
 102
 103   void open(char16ptr_t filename, openmode mode = in) {
 104     std::ifstream::open(filename, mode);
 105   }
 106 };
 107
 108 class OFStream : public std::ofstream {
 109  public:
 110   explicit OFStream(char16ptr_t filename, openmode mode = out)
 111       : std::ofstream(filename, mode) {}
 112
 113   void open(char16ptr_t filename, openmode mode = out) {
 114     std::ofstream::open(filename, mode);
 115   }
 116 };
 117 #else
 118 using IFStream = std::ifstream;
 119 using OFStream = std::ofstream;
 120 #endif
 121
 122 }  // namespace mozilla
 123
 124 #endif /* mozilla_FStream_h */