boost/interprocess/detail/file_wrapper.hpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2006. Distributed under the Boost
   4 // Software License, Version 1.0. (See accompanying file
   5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // See http://www.boost.org/libs/interprocess for documentation.
   8 //
   9 //////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef BOOST_INTERPROCESS_DETAIL_FILE_WRAPPER_HPP
  12 #define BOOST_INTERPROCESS_DETAIL_FILE_WRAPPER_HPP
  13
  14 #include <boost/interprocess/detail/config_begin.hpp>
  15 #include <boost/interprocess/detail/workaround.hpp>
  16 #include <boost/interprocess/detail/os_file_functions.hpp>
  17 #include <boost/interprocess/creation_tags.hpp>
  18 #include <boost/interprocess/detail/move.hpp>
  19 #include <boost/interprocess/creation_tags.hpp>
  20
  21 namespace boost {
  22 namespace interprocess {
  23 namespace detail{
  24
  25 class file_wrapper
  26 {
  27    /// @cond
  28    file_wrapper(file_wrapper&);
  29    file_wrapper & operator=(file_wrapper&);
  30    /// @endcond
  31    public:
  32    BOOST_INTERPROCESS_ENABLE_MOVE_EMULATION(file_wrapper)
  33
  34    //!Default constructor.
  35    //!Represents an empty file_wrapper.
  36    file_wrapper();
  37
  38    //!Creates a file object with name "name" and mode "mode", with the access mode "mode"
  39    //!If the file previously exists, throws an error.
  40    file_wrapper(create_only_t, const char *name, mode_t mode)
  41    {  this->priv_open_or_create(detail::DoCreate, name, mode);  }
  42
  43    //!Tries to create a file with name "name" and mode "mode", with the
  44    //!access mode "mode". If the file previously exists, it tries to open it with mode "mode".
  45    //!Otherwise throws an error.
  46    file_wrapper(open_or_create_t, const char *name, mode_t mode)
  47    {  this->priv_open_or_create(detail::DoOpenOrCreate, name, mode);  }
  48
  49    //!Tries to open a file with name "name", with the access mode "mode".
  50    //!If the file does not previously exist, it throws an error.
  51    file_wrapper(open_only_t, const char *name, mode_t mode)
  52    {  this->priv_open_or_create(detail::DoOpen, name, mode);  }
  53
  54    //!Moves the ownership of "moved"'s file to *this.
  55    //!After the call, "moved" does not represent any file.
  56    //!Does not throw
  57    file_wrapper(BOOST_INTERPROCESS_RV_REF(file_wrapper) moved)
  58    {  this->swap(moved);   }
  59
  60    //!Moves the ownership of "moved"'s file to *this.
  61    //!After the call, "moved" does not represent any file.
  62    //!Does not throw
  63    file_wrapper &operator=(BOOST_INTERPROCESS_RV_REF(file_wrapper) moved)
  64    {
  65       file_wrapper tmp(boost::interprocess::move(moved));
  66       this->swap(tmp);
  67       return *this;
  68    }
  69
  70    //!Swaps to file_wrappers.
  71    //!Does not throw
  72    void swap(file_wrapper &other);
  73
  74    //!Erases a file from the system.
  75    //!Returns false on error. Never throws
  76    static bool remove(const char *name);
  77
  78    //!Sets the size of the file
  79    void truncate(offset_t length);
  80
  81    //!Closes the
  82    //!file
  83    ~file_wrapper();
  84
  85    //!Returns the name of the file
  86    //!used in the constructor
  87    const char *get_name() const;
  88
  89    //!Returns the name of the file
  90    //!used in the constructor
  91    bool get_size(offset_t &size) const;
  92
  93    //!Returns access mode
  94    //!used in the constructor
  95    mode_t get_mode() const;
  96
  97    //!Get mapping handle
  98    //!to use with mapped_region
  99    mapping_handle_t get_mapping_handle() const;
 100
 101    private:
 102    //!Closes a previously opened file mapping. Never throws.
 103    void priv_close();
 104    //!Closes a previously opened file mapping. Never throws.
 105    bool priv_open_or_create(detail::create_enum_t type, const char *filename, mode_t mode);
 106
 107    file_handle_t  m_handle;
 108    mode_t      m_mode;
 109    std::string       m_filename;
 110 };
 111
 112 inline file_wrapper::file_wrapper()
 113    :  m_handle(file_handle_t(detail::invalid_file()))
 114 {}
 115
 116 inline file_wrapper::~file_wrapper()
 117 {  this->priv_close(); }
 118
 119 inline const char *file_wrapper::get_name() const
 120 {  return m_filename.c_str(); }
 121
 122 inline bool file_wrapper::get_size(offset_t &size) const
 123 {  return get_file_size((file_handle_t)m_handle, size);  }
 124
 125 inline void file_wrapper::swap(file_wrapper &other)
 126 {
 127    std::swap(m_handle,  other.m_handle);
 128    std::swap(m_mode,    other.m_mode);
 129    m_filename.swap(other.m_filename);
 130 }
 131
 132 inline mapping_handle_t file_wrapper::get_mapping_handle() const
 133 {  return mapping_handle_from_file_handle(m_handle);  }
 134
 135 inline mode_t file_wrapper::get_mode() const
 136 {  return m_mode; }
 137
 138 inline bool file_wrapper::priv_open_or_create
 139    (detail::create_enum_t type,
 140     const char *filename,
 141     mode_t mode)
 142 {
 143    m_filename = filename;
 144
 145    if(mode != read_only && mode != read_write){
 146       error_info err(mode_error);
 147       throw interprocess_exception(err);
 148    }
 149
 150    //Open file existing native API to obtain the handle
 151    switch(type){
 152       case detail::DoOpen:
 153          m_handle = open_existing_file(filename, mode);
 154       break;
 155       case detail::DoCreate:
 156          m_handle = create_new_file(filename, mode);
 157       break;
 158       case detail::DoOpenOrCreate:
 159          m_handle = create_or_open_file(filename, mode);
 160       break;
 161       default:
 162          {
 163             error_info err = other_error;
 164             throw interprocess_exception(err);
 165          }
 166    }
 167
 168    //Check for error
 169    if(m_handle == invalid_file()){
 170       throw interprocess_exception(error_info(system_error_code()));
 171    }
 172
 173    m_mode = mode;
 174    return true;
 175 }
 176
 177 inline bool file_wrapper::remove(const char *filename)
 178 {  return delete_file(filename); }
 179
 180 inline void file_wrapper::truncate(offset_t length)
 181 {
 182    if(!truncate_file(m_handle, length)){
 183       error_info err(system_error_code());
 184       throw interprocess_exception(err);
 185    }
 186 }
 187
 188 inline void file_wrapper::priv_close()
 189 {
 190    if(m_handle != invalid_file()){
 191       close_file(m_handle);
 192       m_handle = invalid_file();
 193    }
 194 }
 195
 196 }  //namespace detail{
 197 }  //namespace interprocess {
 198 }  //namespace boost {
 199
 200 #include <boost/interprocess/detail/config_end.hpp>
 201
 202 #endif   //BOOST_INTERPROCESS_DETAIL_FILE_WRAPPER_HPP