ceph/src/boost/libs/filesystem/example/error_demo.cpp

   1 //  error_demo.cpp  --------------------------------------------------------------------//
   2
   3 //  Copyright Beman Dawes 2009
   4
   5 //  Distributed under the Boost Software License, Version 1.0.
   6 //  See http://www.boost.org/LICENSE_1_0.txt
   7
   8 //  Library home page: http://www.boost.org/libs/filesystem
   9
  10 //--------------------------------------------------------------------------------------//
  11 //                                                                                      //
  12 //  The purpose of this program is to demonstrate how error reporting works.            //
  13 //                                                                                      //
  14 //--------------------------------------------------------------------------------------//
  15
  16 #include <boost/filesystem.hpp>
  17 #include <boost/system/system_error.hpp>
  18 #include <iostream>
  19
  20 using std::cout;
  21 using boost::filesystem::path;
  22 using boost::filesystem::filesystem_error;
  23 using boost::system::error_code;
  24 using boost::system::system_error;
  25 namespace fs = boost::filesystem;
  26
  27 namespace
  28 {
  29   void report_system_error(const system_error& ex)
  30   {
  31     cout << " threw system_error:\n"
  32          << "    ex.code().value() is " << ex.code().value() << '\n'
  33          << "    ex.code().category().name() is " << ex.code().category().name() << '\n'
  34          << "    ex.what() is " << ex.what() << '\n'
  35          ;
  36   }
  37
  38   void report_filesystem_error(const system_error& ex)
  39   {
  40     cout << "  threw filesystem_error exception:\n"
  41          << "    ex.code().value() is " << ex.code().value() << '\n'
  42          << "    ex.code().category().name() is " << ex.code().category().name() << '\n'
  43          << "    ex.what() is " << ex.what() << '\n'
  44          ;
  45   }
  46
  47   void report_status(fs::file_status s)
  48   {
  49     cout << "  file_status::type() is ";
  50     switch (s.type())
  51     {
  52     case fs::status_error:
  53       cout << "status_error\n"; break;
  54     case fs::file_not_found:
  55       cout << "file_not_found\n"; break;
  56     case fs::regular_file:
  57       cout << "regular_file\n"; break;
  58     case fs::directory_file:
  59       cout << "directory_file\n"; break;
  60     case fs::symlink_file:
  61       cout << "symlink_file\n"; break;
  62     case fs::block_file:
  63       cout << "block_file\n"; break;
  64     case fs::character_file:
  65       cout << "character_file\n"; break;
  66     case fs::fifo_file:
  67       cout << "fifo_file\n"; break;
  68     case fs::socket_file:
  69       cout << "socket_file\n"; break;
  70     case fs::type_unknown:
  71       cout << "type_unknown\n"; break;
  72     default:
  73       cout << "not a valid enumeration constant\n";
  74     }
  75   }
  76
  77   void report_error_code(const error_code& ec)
  78   {
  79     cout << "  ec:\n"
  80          << "    value() is " << ec.value() << '\n'
  81          << "    category().name() is " << ec.category().name() << '\n'
  82          << "    message() is " <<  ec.message() << '\n'
  83          ;
  84   }
  85
  86   bool threw_exception;
  87
  88 }
  89
  90 int main(int argc, char* argv[])
  91 {
  92   if (argc < 2)
  93   {
  94     cout << "Usage: error_demo path\n";
  95     return 1;
  96   }
  97
  98   error_code ec;
  99
 100   ////  construct path - no error_code
 101
 102   //try { path p1(argv[1]); }
 103   //catch (const system_error& ex)
 104   //{
 105   //  cout << "construct path without error_code";
 106   //  report_system_error(ex);
 107   //}
 108
 109   ////  construct path - with error_code
 110
 111   path p (argv[1]);
 112
 113   fs::file_status s;
 114   bool            b (false);
 115   fs::directory_iterator di;
 116
 117   //  get status - no error_code
 118
 119   cout << "\nstatus(\"" << p.string() << "\");\n";
 120   threw_exception = false;
 121
 122   try { s = fs::status(p); }
 123   catch (const system_error& ex)
 124   {
 125     report_filesystem_error(ex);
 126     threw_exception = true;
 127   }
 128   if (!threw_exception)
 129     cout << "  Did not throw exception\n";
 130   report_status(s);
 131
 132   //  get status - with error_code
 133
 134   cout << "\nstatus(\"" << p.string() << "\", ec);\n";
 135   s = fs::status(p, ec);
 136   report_status(s);
 137   report_error_code(ec);
 138
 139   //  query existence - no error_code
 140
 141   cout << "\nexists(\"" << p.string() << "\");\n";
 142   threw_exception = false;
 143
 144   try { b = fs::exists(p); }
 145   catch (const system_error& ex)
 146   {
 147     report_filesystem_error(ex);
 148     threw_exception = true;
 149   }
 150   if (!threw_exception)
 151   {
 152     cout << "  Did not throw exception\n"
 153          << "  Returns: " << (b ? "true" : "false") << '\n';
 154   }
 155
 156   //  query existence - with error_code
 157
 158   //  directory_iterator - no error_code
 159
 160   cout << "\ndirectory_iterator(\"" << p.string() << "\");\n";
 161   threw_exception = false;
 162
 163   try { di = fs::directory_iterator(p); }
 164   catch (const system_error& ex)
 165   {
 166     report_filesystem_error(ex);
 167     threw_exception = true;
 168   }
 169   if (!threw_exception)
 170   {
 171     cout << "  Did not throw exception\n"
 172       << (di == fs::directory_iterator() ? "  Equal" : "  Not equal")
 173       << " to the end iterator\n";
 174   }
 175
 176   //  directory_iterator - with error_code
 177
 178   cout << "\ndirectory_iterator(\"" << p.string() << "\", ec);\n";
 179   di = fs::directory_iterator(p, ec);
 180   cout << (di == fs::directory_iterator() ? "  Equal" : "  Not equal")
 181        << " to the end iterator\n";
 182   report_error_code(ec);
 183
 184   return 0;
 185 }