operations.cpp

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        struct stat path_stat;
        if ( (::stat( ph.c_str(), &path_stat )) != 0 )
          return std::make_pair( error_code( errno, system_category ), false );        
        return std::make_pair( ok, S_ISDIR( path_stat.st_mode )
          ? is_empty_directory( ph )
          : path_stat.st_size == 0 );
      }

      BOOST_FILESYSTEM_DECL query_pair
      equivalent_api( const std::string & ph1, const std::string & ph2 )
      {
        struct stat s2;
        int e2( ::stat( ph2.c_str(), &s2 ) );
        struct stat s1;
        int e1( ::stat( ph1.c_str(), &s1 ) );
        if ( e1 != 0 || e2 != 0 )
          return std::make_pair( error_code( e1 != 0 && e2 != 0 ? errno : 0, system_category ), false );
        // at this point, both stats are known to be valid
        return std::make_pair( ok,
            s1.st_dev == s2.st_dev
            && s1.st_ino == s2.st_ino
            // According to the POSIX stat specs, "The st_ino and st_dev fields
            // taken together uniquely identify the file within the system."
            // Just to be sure, size and mod time are also checked.
            && s1.st_size == s2.st_size
            && s1.st_mtime == s2.st_mtime );
      }
 
      BOOST_FILESYSTEM_DECL uintmax_pair
      file_size_api( const std::string & ph )
      {
        struct stat path_stat;
        if ( ::stat( ph.c_str(), &path_stat ) != 0 )
          return std::make_pair( error_code( errno, system_category ), 0 );
        if ( !S_ISREG( path_stat.st_mode ) )
          return std::make_pair( error_code( EPERM, system_category ), 0 ); 
        return std::make_pair( ok,
          static_cast<boost::uintmax_t>(path_stat.st_size) );
      }

      BOOST_FILESYSTEM_DECL space_pair
      space_api( const std::string & ph )
      {
        struct BOOST_STATVFS vfs;
        space_pair result;
        if ( ::BOOST_STATVFS( ph.c_str(), &vfs ) != 0 )
        {
          result.first = error_code( errno, system_category );
          result.second.capacity = result.second.free
            = result.second.available = 0;
        }
        else
        {
          result.first = ok;
          result.second.capacity 
            = static_cast<boost::uintmax_t>(vfs.f_blocks) * BOOST_STATVFS_F_FRSIZE;
          result.second.free 
            = static_cast<boost::uintmax_t>(vfs.f_bfree) * BOOST_STATVFS_F_FRSIZE;
          result.second.available
            = static_cast<boost::uintmax_t>(vfs.f_bavail) * BOOST_STATVFS_F_FRSIZE;
        }
        return result;
      }

      BOOST_FILESYSTEM_DECL time_pair 
      last_write_time_api( const std::string & ph )
      {
        struct stat path_stat;
        if ( ::stat( ph.c_str(), &path_stat ) != 0 )
          return std::make_pair( error_code( errno, system_category ), 0 );
        return std::make_pair( ok, path_stat.st_mtime );
      }

      BOOST_FILESYSTEM_DECL error_code
      last_write_time_api( const std::string & ph, std::time_t new_value )
      {
        struct stat path_stat;
        if ( ::stat( ph.c_str(), &path_stat ) != 0 )
          return error_code( errno, system_category );
        ::utimbuf buf;
        buf.actime = path_stat.st_atime; // utime() updates access time too:-(
        buf.modtime = new_value;
        return error_code( ::utime( ph.c_str(), &buf ) != 0 ? errno : 0, system_category );
      }

      BOOST_FILESYSTEM_DECL error_code 
      get_current_path_api( std::string & ph )
      {
        for ( long path_max = 32;; path_max *=2 ) // loop 'til buffer large enough
        {
          boost::scoped_array<char>
            buf( new char[static_cast<std::size_t>(path_max)] );
          if ( ::getcwd( buf.get(), static_cast<std::size_t>(path_max) ) == 0 )
          {
            if ( errno != ERANGE
          // bug in some versions of the Metrowerks C lib on the Mac: wrong errno set 
#         if defined(__MSL__) && (defined(macintosh) || defined(__APPLE__) || defined(__APPLE_CC__))
              && errno != 0
#         endif
              ) return error_code( errno, system_category );
          }
          else
          {
            ph = buf.get();
            break;
          }
        }
        return ok;
      }

      BOOST_FILESYSTEM_DECL error_code
      set_current_path_api( const std::string & ph )
      {
        return error_code( ::chdir( ph.c_str() )
          ? errno : 0, system_category );
      }

      BOOST_FILESYSTEM_DECL fs::detail::query_pair
      create_directory_api( const std::string & ph )
      {
        if ( ::mkdir( ph.c_str(), S_IRWXU|S_IRWXG|S_IRWXO ) == 0 )
          { return std::make_pair( ok, true ); }
        int ec=errno;
        error_code dummy;
        if ( ec != EEXIST 
          || !fs::is_directory( status_api( ph, dummy ) ) )
          { return std::make_pair( error_code( ec, system_category ), false ); }
        return std::make_pair( ok, false );
      }

      BOOST_FILESYSTEM_DECL error_code
      create_hard_link_api( const std::string & to_ph,
          const std::string & from_ph )
      {
        return error_code( ::link( to_ph.c_str(), from_ph.c_str() ) == 0
          ? 0 : errno, system_category );
      }

      BOOST_FILESYSTEM_DECL error_code
      create_symlink_api( const std::string & to_ph,
          const std::string & from_ph )
      {
        return error_code( ::symlink( to_ph.c_str(), from_ph.c_str() ) == 0
          ? 0 : errno, system_category ); 
      }

      BOOST_FILESYSTEM_DECL error_code
      remove_api( const std::string & ph )
      {
        if ( posix_remove( ph.c_str() ) == 0 )
          return ok;
        int error = errno;
        // POSIX says "If the directory is not an empty directory, rmdir()
        // shall fail and set errno to EEXIST or ENOTEMPTY."
        // Linux uses ENOTEMPTY, Solaris uses EEXIST.
        if ( error == EEXIST ) error = ENOTEMPTY;

        error_code ec;

        // ignore errors if post-condition satisfied
        return status_api(ph, ec).type() == file_not_found
          ? ok : error_code( error, system_category ) ;
      }

      BOOST_FILESYSTEM_DECL error_code
      rename_api( const std::string & from, const std::string & to )
      {
        // POSIX is too permissive so must check
        error_code dummy;
        if ( fs::exists( status_api( to, dummy ) ) ) 
          return error_code( EEXIST, system_category );
        return error_code( std::rename( from.c_str(), to.c_str() ) != 0 
          ? errno : 0, system_category );
      }

      BOOST_FILESYSTEM_DECL error_code
      copy_file_api( const std::string & from_file_ph,
        const std::string & to_file_ph )
      {
        const std::size_t buf_sz = 32768;
        boost::scoped_array<char> buf( new char [buf_sz] );
        int infile=0, outfile=0;  // init quiets compiler warning
        struct stat from_stat;

        if ( ::stat( from_file_ph.c_str(), &from_stat ) != 0
          || (infile = ::open( from_file_ph.c_str(),
                              O_RDONLY )) < 0
          || (outfile = ::open( to_file_ph.c_str(),
                                O_WRONLY | O_CREAT | O_EXCL,
                                from_stat.st_mode )) < 0 )
        {
          if ( infile >= 0 ) ::close( infile );
          return error_code( errno, system_category );
        }

        ssize_t sz, sz_read=1, sz_write;
        while ( sz_read > 0
          && (sz_read = ::read( infile, buf.get(), buf_sz )) > 0 )
        {
          // Allow for partial writes - see Advanced Unix Programming (2nd Ed.),
          // Marc Rochkind, Addison-Wesley, 2004, page 94
          sz_write = 0;
          do
          {
            if ( (sz = ::write( outfile, buf.get() + sz_write,
              sz_read - sz_write )) < 0 )
            { 
              sz_read = sz; // cause read loop termination
              break;        //  and error to be thrown after closes
            }
            sz_write += sz;
          } while ( sz_write < sz_read );
        }

        if ( ::close( infile) < 0 ) sz_read = -1;
        if ( ::close( outfile) < 0 ) sz_read = -1;

        return error_code( sz_read < 0 ? errno : 0, system_category );
      }

      // this code is based on Stevens and Rago, Advanced Programming in the
      // UNIX envirnment, 2nd Ed., ISBN 0-201-43307-9, page 49
      error_code path_max( std::size_t & result )
      {
#     ifdef PATH_MAX
        static std::size_t max = PATH_MAX;
#     else
        static std::size_t max = 0;
#     endif
        if ( max == 0 )
        {
          errno = 0;
          long tmp = ::pathconf( "/", _PC_NAME_MAX );
          if ( tmp < 0 )
          {
            if ( errno == 0 ) // indeterminate
              max = 4096; // guess
            else return error_code( errno, system_category );
          }
          else max = static_cast<std::size_t>( tmp + 1 ); // relative root
        }
        result = max;
        return ok;
      }

      BOOST_FILESYSTEM_DECL error_code
      dir_itr_first( void *& handle, void *& buffer,
        const std::string & dir, std::string & target,
        file_status &, file_status & )
      {
        if ( (handle = ::opendir( dir.c_str() )) == 0 )
          return error_code( errno, system_category );
        target = std::string( "." ); // string was static but caused trouble
                                     // when iteration called from dtor, after
                                     // static had already been destroyed
        std::size_t path_size;
        error_code ec = path_max( path_size );
        if ( ec ) return ec;
        dirent de;
        buffer = std::malloc( (sizeof(dirent) - sizeof(de.d_name))
          +  path_size + 1 ); // + 1 for "/0"
        return ok;
      }  

      BOOST_FILESYSTEM_DECL error_code
      dir_itr_close( void *& handle, void*& buffer )
      {
        std::free( buffer );
        buffer = 0;
        if ( handle == 0 ) return ok;
        DIR * h( static_cast<DIR*>(handle) );
        handle = 0;
        return error_code( ::closedir( h ) == 0 ? 0 : errno, system_category );
      }

      // warning: the only dirent member updated is d_name
      inline int readdir_r_simulator( DIR * dirp, struct dirent * entry,
        struct dirent ** result ) // *result set to 0 on end of directory
        {
          errno = 0;

    #     if !defined(__CYGWIN__) \
          && defined(_POSIX_THREAD_SAFE_FUNCTIONS) \
          && defined(_SC_THREAD_SAFE_FUNCTIONS) \
          && (_POSIX_THREAD_SAFE_FUNCTIONS+0 >= 0) \
          && (!defined(__hpux) || (defined(__hpux) && defined(_REENTRANT)))
          if ( ::sysconf( _SC_THREAD_SAFE_FUNCTIONS ) >= 0 )
            { return ::readdir_r( dirp, entry, result ); }
    #     endif

          struct dirent * p;
          *result = 0;
          if ( (p = ::readdir( dirp )) == 0 )
            return errno;
          std::strcpy( entry->d_name, p->d_name );
          *result = entry;
          return 0;
        }

      BOOST_FILESYSTEM_DECL error_code
      dir_itr_increment( void *& handle, void *& buffer,
        std::string & target, file_status & sf, file_status & symlink_sf )
      {
        BOOST_ASSERT( buffer != 0 );
        dirent * entry( static_cast<dirent *>(buffer) );
        dirent * result;
        int return_code;
        if ( (return_code = readdir_r_simulator( static_cast<DIR*>(handle),
          entry, &result )) != 0 ) return error_code( errno, system_category );
        if ( result == 0 ) return dir_itr_close( handle, buffer );
        target = entry->d_name;
#     ifdef BOOST_FILESYSTEM_STATUS_CACHE
        if ( entry->d_type == DT_UNKNOWN )  // filesystem does not supply d_type value
        {
          sf = symlink_sf = fs::file_status(fs::status_unknown);
        }
        else  // filesystem supplies d_type value
        {
          if ( entry->d_type == DT_DIR )
            sf = symlink_sf = fs::file_status( fs::directory_file );
          else if ( entry->d_type == DT_REG )
            sf = symlink_sf = fs::file_status( fs::regular_file );
          else if ( entry->d_type == DT_LNK )
          {
            sf = fs::file_status( fs::status_unknown );
            symlink_sf = fs::file_status( fs::symlink_file );
          }
          else sf = symlink_sf = fs::file_status( fs::status_unknown );
        }
#     else
        sf = symlink_sf = fs::file_status( fs::status_unknown );
#     endif
        return ok;
      }

#   endif
    } // namespace detail
  } // namespace filesystem
} // namespace boost