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 {
  34 public:
  35   explicit IFStream(char16ptr_t filename, openmode mode = in);
  36
  37   std::filebuf* rdbuf() const { return mFileBuf.get(); }
  38
  39   bool is_open() const { return mFileBuf && mFileBuf->is_open(); }
  40   void open(char16ptr_t filename, openmode mode = in);
  41   void close() { mFileBuf && mFileBuf->close(); }
  42
  43 private:
  44   UniquePtr<std::filebuf> mFileBuf;
  45 };
  46
  47 inline
  48 IFStream::IFStream(char16ptr_t filename, openmode mode)
  49   : std::istream(nullptr)
  50 {
  51   open(filename, mode);
  52 }
  53
  54 inline void
  55 IFStream::open(char16ptr_t filename, openmode mode)
  56 {
  57   int fmode = _O_RDONLY;
  58   if (mode & binary) {
  59     fmode |= _O_BINARY;
  60   } else {
  61     fmode |= _O_TEXT;
  62   }
  63   int fd = _wopen(filename, fmode);
  64   mFileBuf = MakeUnique<__gnu_cxx::stdio_filebuf<char>>(fd, mode);
  65   std::istream::rdbuf(mFileBuf.get());
  66 }
  67
  68 class OFStream : public std::ostream
  69 {
  70 public:
  71   explicit OFStream(char16ptr_t filename, openmode mode = out);
  72
  73   std::filebuf* rdbuf() const { return mFileBuf.get(); }
  74
  75   bool is_open() const { return mFileBuf && mFileBuf->is_open(); }
  76   void open(char16ptr_t filename, openmode mode = out);
  77   void close() { mFileBuf && mFileBuf->close(); }
  78
  79 private:
  80   UniquePtr<std::filebuf> mFileBuf;
  81 };
  82
  83 inline
  84 OFStream::OFStream(char16ptr_t filename, openmode mode)
  85   : std::ostream(nullptr)
  86 {
  87   open(filename, mode);
  88 }
  89
  90 inline void
  91 OFStream::open(char16ptr_t filename, openmode mode)
  92 {
  93   int fmode = _O_WRONLY;
  94   if (mode & binary) {
  95     fmode |= _O_BINARY;
  96   } else {
  97     fmode |= _O_TEXT;
  98   }
  99   if (mode & trunc) {
 100     fmode |= _O_CREAT | _O_TRUNC;
 101   }
 102   int fd = _wopen(filename, fmode);
 103   mFileBuf = MakeUnique<__gnu_cxx::stdio_filebuf<char>>(fd, mode);
 104   std::ostream::rdbuf(mFileBuf.get());
 105 }
 106
 107 #elif defined(XP_WIN)
 108 class IFStream : public std::ifstream
 109 {
 110 public:
 111   explicit IFStream(char16ptr_t filename, openmode mode = in)
 112     : std::ifstream(filename, mode) {}
 113
 114   void open(char16ptr_t filename, openmode mode = in)
 115   {
 116     std::ifstream::open(filename, mode);
 117   }
 118 };
 119
 120 class OFStream : public std::ofstream
 121 {
 122 public:
 123   explicit OFStream(char16ptr_t filename, openmode mode = out)
 124     : std::ofstream(filename, mode) {}
 125
 126   void open(char16ptr_t filename, openmode mode = out)
 127   {
 128     std::ofstream::open(filename, mode);
 129   }
 130 };
 131 #else
 132 using IFStream = std::ifstream;
 133 using OFStream = std::ofstream;
 134 #endif
 135
 136 } // namespace mozilla
 137
 138 #endif /* mozilla_FStream_h */