boost/interprocess/file_mapping.hpp
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2012. 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/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_INTERPROCESS_FILE_MAPPING_HPP
#define BOOST_INTERPROCESS_FILE_MAPPING_HPP
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <boost/interprocess/interprocess_fwd.hpp>
#include <boost/interprocess/exceptions.hpp>
#include <boost/interprocess/detail/utilities.hpp>
#include <boost/interprocess/creation_tags.hpp>
#include <boost/interprocess/detail/os_file_functions.hpp>
#include <boost/move/move.hpp>
#include <string> //std::string
//!\file
//!Describes file_mapping and mapped region classes
namespace boost {
namespace interprocess {
//!A class that wraps a file-mapping that can be used to
//!create mapped regions from the mapped files
class file_mapping
{
/// @cond
BOOST_MOVABLE_BUT_NOT_COPYABLE(file_mapping)
/// @endcond
public:
//!Constructs an empty file mapping.
//!Does not throw
file_mapping();
//!Opens a file mapping of file "filename", starting in offset
//!"file_offset", and the mapping's size will be "size". The mapping
//!can be opened for read-only "read_only" or read-write "read_write"
//!modes. Throws interprocess_exception on error.
file_mapping(const char *filename, mode_t mode);
//!Moves the ownership of "moved"'s file mapping object to *this.
//!After the call, "moved" does not represent any file mapping object.
//!Does not throw
file_mapping(BOOST_RV_REF(file_mapping) moved)
: m_handle(file_handle_t(ipcdetail::invalid_file()))
, m_mode(read_only)
{ this->swap(moved); }
//!Moves the ownership of "moved"'s file mapping to *this.
//!After the call, "moved" does not represent any file mapping.
//!Does not throw
file_mapping &operator=(BOOST_RV_REF(file_mapping) moved)
{
file_mapping tmp(boost::move(moved));
this->swap(tmp);
return *this;
}
//!Swaps to file_mappings.
//!Does not throw.
void swap(file_mapping &other);
//!Returns access mode
//!used in the constructor
mode_t get_mode() const;
//!Obtains the mapping handle
//!to be used with mapped_region
mapping_handle_t get_mapping_handle() const;
//!Destroys the file mapping. All mapped regions created from this are still
//!valid. Does not throw
~file_mapping();
//!Returns the name of the file
//!used in the constructor.
const char *get_name() const;
//!Removes the file named "filename" even if it's been memory mapped.
//!Returns true on success.
//!The function might fail in some operating systems if the file is
//!being used other processes and no deletion permission was shared.
static bool remove(const char *filename);
/// @cond
private:
//!Closes a previously opened file mapping. Never throws.
void priv_close();
file_handle_t m_handle;
mode_t m_mode;
std::string m_filename;
/// @endcond
};
inline file_mapping::file_mapping()
: m_handle(file_handle_t(ipcdetail::invalid_file()))
, m_mode(read_only)
{}
inline file_mapping::~file_mapping()
{ this->priv_close(); }
inline const char *file_mapping::get_name() const
{ return m_filename.c_str(); }
inline void file_mapping::swap(file_mapping &other)
{
std::swap(m_handle, other.m_handle);
std::swap(m_mode, other.m_mode);
m_filename.swap(other.m_filename);
}
inline mapping_handle_t file_mapping::get_mapping_handle() const
{ return ipcdetail::mapping_handle_from_file_handle(m_handle); }
inline mode_t file_mapping::get_mode() const
{ return m_mode; }
inline file_mapping::file_mapping
(const char *filename, mode_t mode)
: m_filename(filename)
{
//Check accesses
if (mode != read_write && mode != read_only){
error_info err = other_error;
throw interprocess_exception(err);
}
//Open file
m_handle = ipcdetail::open_existing_file(filename, mode);
//Check for error
if(m_handle == ipcdetail::invalid_file()){
error_info err = system_error_code();
this->priv_close();
throw interprocess_exception(err);
}
m_mode = mode;
}
inline bool file_mapping::remove(const char *filename)
{ return ipcdetail::delete_file(filename); }
///@cond
inline void file_mapping::priv_close()
{
if(m_handle != ipcdetail::invalid_file()){
ipcdetail::close_file(m_handle);
m_handle = ipcdetail::invalid_file();
}
}
///@endcond
//!A class that stores the name of a file
//!and tries to remove it in its destructor
//!Useful to remove temporary files in the presence
//!of exceptions
class remove_file_on_destroy
{
const char * m_name;
public:
remove_file_on_destroy(const char *name)
: m_name(name)
{}
~remove_file_on_destroy()
{ ipcdetail::delete_file(m_name); }
};
} //namespace interprocess {
} //namespace boost {
#include <boost/interprocess/detail/config_end.hpp>
#endif //BOOST_INTERPROCESS_FILE_MAPPING_HPP