Ticket #2998: flushable_file.hpp

// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
// (C) Copyright 2003-2007 Jonathan Turkanis
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)

// See http://www.boost.org/libs/iostreams for documentation.

//
// Contains wrappers for standard file buffers, together
// with convenience typedefs:
//      - flushable_basic_file_sink
//      - flushable_basic_file
//

// Copied from boost_1_38_0/boost/iostreams/device/file.hpp.

#ifndef BOOST_IOSTREAMS_FLUSHABLE_FILE_HPP_INCLUDED
#define BOOST_IOSTREAMS_FLUSHABLE_FILE_HPP_INCLUDED

#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif

#include <boost/iostreams/detail/config/wide_streams.hpp>
#ifndef BOOST_IOSTREAMS_NO_LOCALE
# include <locale>
#endif
#include <string>                               // pathnames, char_traits.
#include <boost/iostreams/categories.hpp>
#include <boost/iostreams/detail/ios.hpp>       // openmode, seekdir, int types.
#include <boost/iostreams/detail/fstream.hpp>
#include <boost/iostreams/operations.hpp>       // seek.
#include <boost/shared_ptr.hpp>

// Must come last.
#include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC.

namespace boost { namespace iostreams {

template<typename Ch>
class flushable_basic_file {
public:
    typedef Ch char_type;
    struct category
        : public seekable_device_tag,
          public closable_tag,
          public localizable_tag,
          public flushable_tag
        { };
    flushable_basic_file( const std::string& path,
                BOOST_IOS::openmode mode =
                    BOOST_IOS::in | BOOST_IOS::out,
                BOOST_IOS::openmode base_mode =
                    BOOST_IOS::in | BOOST_IOS::out );
    std::streamsize read(char_type* s, std::streamsize n);
    std::streamsize write(const char_type* s, std::streamsize n);
    std::streampos seek( stream_offset off, BOOST_IOS::seekdir way,
                         BOOST_IOS::openmode which =
                             BOOST_IOS::in | BOOST_IOS::out );
    void open( const std::string& path,
               BOOST_IOS::openmode mode =
                   BOOST_IOS::in | BOOST_IOS::out,
               BOOST_IOS::openmode base_mode =
                   BOOST_IOS::in | BOOST_IOS::out );
    bool is_open() const;
    void close();
    bool flush();
#ifndef BOOST_IOSTREAMS_NO_LOCALE
    void imbue(const std::locale& loc) { pimpl_->file_.pubimbue(loc);  }
#endif
private:
    struct impl {
        impl(const std::string& path, BOOST_IOS::openmode mode)
            { file_.open(path.c_str(), mode); }
        ~impl() { if (file_.is_open()) file_.close(); }
        BOOST_IOSTREAMS_BASIC_FILEBUF(Ch) file_;
    };
    shared_ptr<impl> pimpl_;
};

typedef flushable_basic_file<char>     flushable_file;
typedef flushable_basic_file<wchar_t>  flushable_wfile;

template<typename Ch>
struct flushable_basic_file_sink : private flushable_basic_file<Ch> {
    typedef Ch char_type;
    struct category
        : output_seekable,
          device_tag,
          closable_tag,
          flushable_tag
        { };
    using flushable_basic_file<Ch>::write;
    using flushable_basic_file<Ch>::seek;
    using flushable_basic_file<Ch>::is_open;
    using flushable_basic_file<Ch>::close;
    using flushable_basic_file<Ch>::flush;
    flushable_basic_file_sink( const std::string& path,
                     BOOST_IOS::openmode mode = BOOST_IOS::out )
        : flushable_basic_file<Ch>(path, mode & ~BOOST_IOS::in, BOOST_IOS::out)
        { }
    void open( const std::string& path,
               BOOST_IOS::openmode mode = BOOST_IOS::out )
    {
        flushable_basic_file<Ch>::open(path, mode & ~BOOST_IOS::in, BOOST_IOS::out);
    }
};

typedef flushable_basic_file_sink<char>     flushable_file_sink;
typedef flushable_basic_file_sink<wchar_t>  flushable_wfile_sink;

//------------------Implementation of basic_file------------------------------//

template<typename Ch>
flushable_basic_file<Ch>::flushable_basic_file
    ( const std::string& path, BOOST_IOS::openmode mode,
      BOOST_IOS::openmode base_mode )
{
    open(path, mode, base_mode);
}

template<typename Ch>
inline std::streamsize flushable_basic_file<Ch>::read
    (char_type* s, std::streamsize n)
{
    std::streamsize result = pimpl_->file_.sgetn(s, n);
    return result != 0 ? result : -1;
}

template<typename Ch>
inline std::streamsize flushable_basic_file<Ch>::write
    (const char_type* s, std::streamsize n)
{ return pimpl_->file_.sputn(s, n); }

template<typename Ch>
std::streampos flushable_basic_file<Ch>::seek
    ( stream_offset off, BOOST_IOS::seekdir way,
      BOOST_IOS::openmode )
{ return iostreams::seek(pimpl_->file_, off, way); }

template<typename Ch>
void flushable_basic_file<Ch>::open
    ( const std::string& path, BOOST_IOS::openmode mode,
      BOOST_IOS::openmode base_mode )
{
    pimpl_.reset(new impl(path, mode | base_mode));
}

template<typename Ch>
bool flushable_basic_file<Ch>::is_open() const { return pimpl_->file_.is_open(); }

template<typename Ch>
void flushable_basic_file<Ch>::close() { pimpl_->file_.close(); }

template<typename Ch>
bool flushable_basic_file<Ch>::flush() { pimpl_->file_.pubsync(); return true;}

//----------------------------------------------------------------------------//

} } // End namespaces iostreams, boost.

#include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC

#endif // #ifndef BOOST_IOSTREAMS_FILE_HPP_INCLUDED