ceph/src/Beast/extras/beast/test/fail_counter.hpp

   1 //
   2 // Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7
   8 #ifndef BEAST_TEST_FAIL_COUNTER_HPP
   9 #define BEAST_TEST_FAIL_COUNTER_HPP
  10
  11 #include <beast/core/error.hpp>
  12
  13 namespace beast {
  14 namespace test {
  15
  16 enum class error
  17 {
  18     fail_error = 1
  19 };
  20
  21 namespace detail {
  22
  23 class fail_error_category : public boost::system::error_category
  24 {
  25 public:
  26     const char*
  27     name() const noexcept override
  28     {
  29         return "test";
  30     }
  31
  32     std::string
  33     message(int ev) const override
  34     {
  35         switch(static_cast<error>(ev))
  36         {
  37         default:
  38         case error::fail_error:
  39             return "test error";
  40         }
  41     }
  42
  43     boost::system::error_condition
  44     default_error_condition(int ev) const noexcept override
  45     {
  46         return boost::system::error_condition{ev, *this};
  47     }
  48
  49     bool
  50     equivalent(int ev,
  51         boost::system::error_condition const& condition
  52             ) const noexcept override
  53     {
  54         return condition.value() == ev &&
  55             &condition.category() == this;
  56     }
  57
  58     bool
  59     equivalent(error_code const& error, int ev) const noexcept override
  60     {
  61         return error.value() == ev &&
  62             &error.category() == this;
  63     }
  64 };
  65
  66 inline
  67 boost::system::error_category const&
  68 get_error_category()
  69 {
  70     static fail_error_category const cat{};
  71     return cat;
  72 }
  73
  74 } // detail
  75
  76 inline
  77 error_code
  78 make_error_code(error ev)
  79 {
  80     return error_code{
  81         static_cast<std::underlying_type<error>::type>(ev),
  82             detail::get_error_category()};
  83 }
  84
  85 /** A countdown to simulated failure.
  86
  87     On the Nth operation, the class will fail with the specified
  88     error code, or the default error code of @ref error::fail_error.
  89 */
  90 class fail_counter
  91 {
  92     std::size_t n_;
  93     error_code ec_;
  94
  95 public:
  96     fail_counter(fail_counter&&) = default;
  97
  98     /** Construct a counter.
  99
 100         @param The 0-based index of the operation to fail on or after.
 101     */
 102     explicit
 103     fail_counter(std::size_t n,
 104             error_code ev = make_error_code(error::fail_error))
 105         : n_(n)
 106         , ec_(ev)
 107     {
 108     }
 109
 110     /// Throw an exception on the Nth failure
 111     void
 112     fail()
 113     {
 114         if(n_ > 0)
 115             --n_;
 116         if(! n_)
 117             throw system_error{ec_};
 118     }
 119
 120     /// Set an error code on the Nth failure
 121     bool
 122     fail(error_code& ec)
 123     {
 124         if(n_ > 0)
 125             --n_;
 126         if(! n_)
 127         {
 128             ec = ec_;
 129             return true;
 130         }
 131         return false;
 132     }
 133 };
 134
 135 } // test
 136 } // beast
 137
 138 namespace boost {
 139 namespace system {
 140 template<>
 141 struct is_error_code_enum<beast::test::error>
 142 {
 143     static bool const value = true;
 144 };
 145 } // system
 146 } // boost
 147
 148 #endif