external/bsd/libc++/dist/libcxx/src/future.cpp

   1 //===------------------------- future.cpp ---------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is dual licensed under the MIT and the University of Illinois Open
   6 // Source Licenses. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "future"
  11 #include "string"
  12
  13 _LIBCPP_BEGIN_NAMESPACE_STD
  14
  15 class _LIBCPP_HIDDEN __future_error_category
  16     : public __do_message
  17 {
  18 public:
  19     virtual const char* name() const _NOEXCEPT;
  20     virtual string message(int ev) const;
  21 };
  22
  23 const char*
  24 __future_error_category::name() const _NOEXCEPT
  25 {
  26     return "future";
  27 }
  28
  29 #pragma clang diagnostic push
  30 #pragma clang diagnostic ignored "-Wswitch"
  31
  32 string
  33 __future_error_category::message(int ev) const
  34 {
  35     switch (static_cast<future_errc>(ev))
  36     {
  37     case future_errc(0):  // For backwards compatibility with C++11 (LWG 2056)
  38     case future_errc::broken_promise:
  39         return string("The associated promise has been destructed prior "
  40                       "to the associated state becoming ready.");
  41     case future_errc::future_already_retrieved:
  42         return string("The future has already been retrieved from "
  43                       "the promise or packaged_task.");
  44     case future_errc::promise_already_satisfied:
  45         return string("The state of the promise has already been set.");
  46     case future_errc::no_state:
  47         return string("Operation not permitted on an object without "
  48                       "an associated state.");
  49     }
  50     return string("unspecified future_errc value\n");
  51 }
  52
  53 #pragma clang diagnostic pop
  54
  55 const error_category&
  56 future_category() _NOEXCEPT
  57 {
  58     static __future_error_category __f;
  59     return __f;
  60 }
  61
  62 future_error::future_error(error_code __ec)
  63     : logic_error(__ec.message()),
  64       __ec_(__ec)
  65 {
  66 }
  67
  68 future_error::~future_error() _NOEXCEPT
  69 {
  70 }
  71
  72 void
  73 __assoc_sub_state::__on_zero_shared() _NOEXCEPT
  74 {
  75     delete this;
  76 }
  77
  78 void
  79 __assoc_sub_state::set_value()
  80 {
  81     unique_lock<mutex> __lk(__mut_);
  82 #ifndef _LIBCPP_NO_EXCEPTIONS
  83     if (__has_value())
  84         throw future_error(make_error_code(future_errc::promise_already_satisfied));
  85 #endif
  86     __state_ |= __constructed | ready;
  87     __cv_.notify_all();
  88     __lk.unlock();
  89 }
  90
  91 void
  92 __assoc_sub_state::set_value_at_thread_exit()
  93 {
  94     unique_lock<mutex> __lk(__mut_);
  95 #ifndef _LIBCPP_NO_EXCEPTIONS
  96     if (__has_value())
  97         throw future_error(make_error_code(future_errc::promise_already_satisfied));
  98 #endif
  99     __state_ |= __constructed;
 100     __thread_local_data()->__make_ready_at_thread_exit(this);
 101     __lk.unlock();
 102 }
 103
 104 void
 105 __assoc_sub_state::set_exception(exception_ptr __p)
 106 {
 107     unique_lock<mutex> __lk(__mut_);
 108 #ifndef _LIBCPP_NO_EXCEPTIONS
 109     if (__has_value())
 110         throw future_error(make_error_code(future_errc::promise_already_satisfied));
 111 #endif
 112     __exception_ = __p;
 113     __state_ |= ready;
 114     __lk.unlock();
 115     __cv_.notify_all();
 116 }
 117
 118 void
 119 __assoc_sub_state::set_exception_at_thread_exit(exception_ptr __p)
 120 {
 121     unique_lock<mutex> __lk(__mut_);
 122 #ifndef _LIBCPP_NO_EXCEPTIONS
 123     if (__has_value())
 124         throw future_error(make_error_code(future_errc::promise_already_satisfied));
 125 #endif
 126     __exception_ = __p;
 127     __thread_local_data()->__make_ready_at_thread_exit(this);
 128     __lk.unlock();
 129 }
 130
 131 void
 132 __assoc_sub_state::__make_ready()
 133 {
 134     unique_lock<mutex> __lk(__mut_);
 135     __state_ |= ready;
 136     __lk.unlock();
 137     __cv_.notify_all();
 138 }
 139
 140 void
 141 __assoc_sub_state::copy()
 142 {
 143     unique_lock<mutex> __lk(__mut_);
 144     __sub_wait(__lk);
 145     if (__exception_ != nullptr)
 146         rethrow_exception(__exception_);
 147 }
 148
 149 void
 150 __assoc_sub_state::wait()
 151 {
 152     unique_lock<mutex> __lk(__mut_);
 153     __sub_wait(__lk);
 154 }
 155
 156 void
 157 __assoc_sub_state::__sub_wait(unique_lock<mutex>& __lk)
 158 {
 159     if (!__is_ready())
 160     {
 161         if (__state_ & static_cast<unsigned>(deferred))
 162         {
 163             __state_ &= ~static_cast<unsigned>(deferred);
 164             __lk.unlock();
 165             __execute();
 166         }
 167         else
 168             while (!__is_ready())
 169                 __cv_.wait(__lk);
 170     }
 171 }
 172
 173 void
 174 __assoc_sub_state::__execute()
 175 {
 176 #ifndef _LIBCPP_NO_EXCEPTIONS
 177     throw future_error(make_error_code(future_errc::no_state));
 178 #endif
 179 }
 180
 181 future<void>::future(__assoc_sub_state* __state)
 182     : __state_(__state)
 183 {
 184 #ifndef _LIBCPP_NO_EXCEPTIONS
 185     if (__state_->__has_future_attached())
 186         throw future_error(make_error_code(future_errc::future_already_retrieved));
 187 #endif
 188     __state_->__add_shared();
 189     __state_->__set_future_attached();
 190 }
 191
 192 future<void>::~future()
 193 {
 194     if (__state_)
 195         __state_->__release_shared();
 196 }
 197
 198 void
 199 future<void>::get()
 200 {
 201     unique_ptr<__shared_count, __release_shared_count> __(__state_);
 202     __assoc_sub_state* __s = __state_;
 203     __state_ = nullptr;
 204     __s->copy();
 205 }
 206
 207 promise<void>::promise()
 208     : __state_(new __assoc_sub_state)
 209 {
 210 }
 211
 212 promise<void>::~promise()
 213 {
 214     if (__state_)
 215     {
 216         if (!__state_->__has_value() && __state_->use_count() > 1)
 217             __state_->set_exception(make_exception_ptr(
 218                       future_error(make_error_code(future_errc::broken_promise))
 219                                                       ));
 220         __state_->__release_shared();
 221     }
 222 }
 223
 224 future<void>
 225 promise<void>::get_future()
 226 {
 227 #ifndef _LIBCPP_NO_EXCEPTIONS
 228     if (__state_ == nullptr)
 229         throw future_error(make_error_code(future_errc::no_state));
 230 #endif
 231     return future<void>(__state_);
 232 }
 233
 234 void
 235 promise<void>::set_value()
 236 {
 237 #ifndef _LIBCPP_NO_EXCEPTIONS
 238     if (__state_ == nullptr)
 239         throw future_error(make_error_code(future_errc::no_state));
 240 #endif
 241     __state_->set_value();
 242 }
 243
 244 void
 245 promise<void>::set_exception(exception_ptr __p)
 246 {
 247 #ifndef _LIBCPP_NO_EXCEPTIONS
 248     if (__state_ == nullptr)
 249         throw future_error(make_error_code(future_errc::no_state));
 250 #endif
 251     __state_->set_exception(__p);
 252 }
 253
 254 void
 255 promise<void>::set_value_at_thread_exit()
 256 {
 257 #ifndef _LIBCPP_NO_EXCEPTIONS
 258     if (__state_ == nullptr)
 259         throw future_error(make_error_code(future_errc::no_state));
 260 #endif
 261     __state_->set_value_at_thread_exit();
 262 }
 263
 264 void
 265 promise<void>::set_exception_at_thread_exit(exception_ptr __p)
 266 {
 267 #ifndef _LIBCPP_NO_EXCEPTIONS
 268     if (__state_ == nullptr)
 269         throw future_error(make_error_code(future_errc::no_state));
 270 #endif
 271     __state_->set_exception_at_thread_exit(__p);
 272 }
 273
 274 shared_future<void>::~shared_future()
 275 {
 276     if (__state_)
 277         __state_->__release_shared();
 278 }
 279
 280 shared_future<void>&
 281 shared_future<void>::operator=(const shared_future& __rhs)
 282 {
 283     if (__rhs.__state_)
 284         __rhs.__state_->__add_shared();
 285     if (__state_)
 286         __state_->__release_shared();
 287     __state_ = __rhs.__state_;
 288     return *this;
 289 }
 290
 291 _LIBCPP_END_NAMESPACE_STD