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| 1 | // Copyright (c) 2007-2016 Hartmut Kaiser | |
| 2 | // | |
| 3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| 4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
| 5 | ||
| 6 | #if !defined(HPX_LCOS_DETAIL_FUTURE_DATA_MAR_06_2012_1055AM) | |
| 7 | #define HPX_LCOS_DETAIL_FUTURE_DATA_MAR_06_2012_1055AM | |
| 8 | ||
| 9 | #include <hpx/config.hpp> | |
| 10 | #include <hpx/error_code.hpp> | |
| 11 | #include <hpx/lcos/local/detail/condition_variable.hpp> | |
| 12 | #include <hpx/lcos/local/spinlock.hpp> | |
| 13 | #include <hpx/runtime/get_worker_thread_num.hpp> | |
| 14 | #include <hpx/runtime/launch_policy.hpp> | |
| 15 | #include <hpx/runtime/threads/thread_executor.hpp> | |
| 16 | #include <hpx/runtime/threads/thread_helpers.hpp> | |
| 17 | #include <hpx/runtime/threads/coroutines/detail/get_stack_pointer.hpp> | |
| 18 | #include <hpx/throw_exception.hpp> | |
| 19 | #include <hpx/traits/get_remote_result.hpp> | |
| 20 | #include <hpx/util/atomic_count.hpp> | |
| 21 | #include <hpx/util/bind.hpp> | |
| 22 | #include <hpx/util/decay.hpp> | |
| 23 | #include <hpx/util/deferred_call.hpp> | |
| 24 | #include <hpx/util/steady_clock.hpp> | |
| 25 | #include <hpx/util/unique_function.hpp> | |
| 26 | #include <hpx/util/unused.hpp> | |
| 27 | ||
| 28 | #include <boost/exception_ptr.hpp> | |
| 29 | #include <boost/intrusive_ptr.hpp> | |
| 30 | ||
| 31 | #include <chrono> | |
| 32 | #include <cstddef> | |
| 33 | #include <functional> | |
| 34 | #include <memory> | |
| 35 | #include <mutex> | |
| 36 | #include <type_traits> | |
| 37 | #include <utility> | |
| 38 | ||
| 39 | /////////////////////////////////////////////////////////////////////////////// | |
| 40 | namespace hpx { namespace lcos | |
| 41 | { | |
| 42 | enum class future_status | |
| 43 | { | |
| 44 | ready, timeout, deferred, uninitialized | |
| 45 | }; | |
| 46 | }} | |
| 47 | ||
| 48 | /////////////////////////////////////////////////////////////////////////////// | |
| 49 | namespace hpx { namespace lcos | |
| 50 | { | |
| 51 | ||
| 52 | namespace detail | |
| 53 | { | |
| 54 | template <typename Result> struct future_data; | |
| 55 | ||
| 56 | /////////////////////////////////////////////////////////////////////// | |
| 57 | struct future_data_refcnt_base; | |
| 58 | ||
| 59 | void intrusive_ptr_add_ref(future_data_refcnt_base* p); | |
| 60 | void intrusive_ptr_release(future_data_refcnt_base* p); | |
| 61 | ||
| 62 | /////////////////////////////////////////////////////////////////////// | |
| 63 | struct future_data_refcnt_base | |
| 64 | { | |
| 65 | private: | |
| 66 | typedef util::unique_function_nonser<void()> completed_callback_type; | |
| 67 | public: | |
| 68 | typedef void has_future_data_refcnt_base; | |
| 69 | ||
| 70 | virtual ~future_data_refcnt_base() {} | |
| 71 | ||
| 72 | virtual void set_on_completed(completed_callback_type) = 0; | |
| 73 | ||
| 74 | virtual bool requires_delete() | |
| 75 | { | |
| 76 | return 0 == --count_; | |
| 77 | } | |
| 78 | ||
| 79 | virtual void destroy() | |
| 80 | { | |
| 81 | delete this; | |
| 82 | } | |
| 83 | ||
| 84 | protected: | |
| 85 | future_data_refcnt_base() : count_(0) {} | |
| 86 | ||
| 87 | // reference counting | |
| 88 | friend void intrusive_ptr_add_ref(future_data_refcnt_base* p); | |
| 89 | friend void intrusive_ptr_release(future_data_refcnt_base* p); | |
| 90 | ||
| 91 | util::atomic_count count_; | |
| 92 | }; | |
| 93 | ||
| 94 | /// support functions for boost::intrusive_ptr | |
| 95 | inline void intrusive_ptr_add_ref(future_data_refcnt_base* p) | |
| 96 | { | |
| 97 | ++p->count_; | |
| 98 | } | |
| 99 | inline void intrusive_ptr_release(future_data_refcnt_base* p) | |
| 100 | { | |
| 101 | if (p->requires_delete()) | |
| 102 | p->destroy(); | |
| 103 | } | |
| 104 | ||
| 105 | /////////////////////////////////////////////////////////////////////////// | |
| 106 | template <typename Result> | |
| 107 | struct future_data_result | |
| 108 | { | |
| 109 | typedef Result type; | |
| 110 | ||
| 111 | template <typename U> | |
| 112 | HPX_FORCEINLINE static | |
| 113 | U && set(U && u) | |
| 114 | { | |
| 115 | return std::forward<U>(u); | |
| 116 | } | |
| 117 | }; | |
| 118 | ||
| 119 | template <typename Result> | |
| 120 | struct future_data_result<Result&> | |
| 121 | { | |
| 122 | typedef Result* type; | |
| 123 | ||
| 124 | HPX_FORCEINLINE static | |
| 125 | Result* set(Result* u) | |
| 126 | { | |
| 127 | return u; | |
| 128 | } | |
| 129 | ||
| 130 | HPX_FORCEINLINE static | |
| 131 | Result* set(Result& u) | |
| 132 | { | |
| 133 | return &u; | |
| 134 | } | |
| 135 | }; | |
| 136 | ||
| 137 | template <> | |
| 138 | struct future_data_result<void> | |
| 139 | { | |
| 140 | typedef util::unused_type type; | |
| 141 | ||
| 142 | HPX_FORCEINLINE static | |
| 143 | util::unused_type set(util::unused_type u) | |
| 144 | { | |
| 145 | return u; | |
| 146 | } | |
| 147 | }; | |
| 148 | ||
| 149 | /////////////////////////////////////////////////////////////////////////// | |
| 150 | template <typename R> | |
| 151 | struct future_data_storage | |
| 152 | { | |
| 153 | typedef typename future_data_result<R>::type value_type; | |
| 154 | typedef boost::exception_ptr error_type; | |
| 155 | ||
| 156 | // determine the required alignment, define aligned storage of proper | |
| 157 | // size | |
| 158 | HPX_STATIC_CONSTEXPR std::size_t max_alignment = | |
| 159 | (std::alignment_of<value_type>::value > | |
| 160 | std::alignment_of<error_type>::value) ? | |
| 161 | std::alignment_of<value_type>::value | |
| 162 | : std::alignment_of<error_type>::value; | |
| 163 | ||
| 164 | HPX_STATIC_CONSTEXPR std::size_t max_size = | |
| 165 | (sizeof(value_type) > sizeof(error_type)) ? | |
| 166 | sizeof(value_type) : sizeof(error_type); | |
| 167 | ||
| 168 | typedef typename std::aligned_storage<max_size, max_alignment>::type type; | |
| 169 | }; | |
| 170 | ||
| 171 | /////////////////////////////////////////////////////////////////////////// | |
| 172 | template <typename F1, typename F2> | |
| 173 | class compose_cb_impl | |
| 174 | { | |
| 175 | HPX_MOVABLE_ONLY(compose_cb_impl); | |
| 176 | ||
| 177 | public: | |
| 178 | template <typename A1, typename A2> | |
| 179 | compose_cb_impl(A1 && f1, A2 && f2) | |
| 180 | : f1_(std::forward<A1>(f1)) | |
| 181 | , f2_(std::forward<A2>(f2)) | |
| 182 | {} | |
| 183 | ||
| 184 | compose_cb_impl(compose_cb_impl&& other) | |
| 185 | : f1_(std::move(other.f1_)) | |
| 186 | , f2_(std::move(other.f2_)) | |
| 187 | {} | |
| 188 | ||
| 189 | void operator()() const | |
| 190 | { | |
| 191 | f1_(); | |
| 192 | f2_(); | |
| 193 | } | |
| 194 | ||
| 195 | private: | |
| 196 | F1 f1_; | |
| 197 | F2 f2_; | |
| 198 | }; | |
| 199 | ||
| 200 | template <typename F1, typename F2> | |
| 201 | static HPX_FORCEINLINE util::unique_function_nonser<void()> | |
| 202 | compose_cb(F1 && f1, F2 && f2) | |
| 203 | { | |
| 204 | if (!f1) | |
| 205 | return std::forward<F2>(f2); | |
| 206 | else if (!f2) | |
| 207 | return std::forward<F1>(f1); | |
| 208 | ||
| 209 | // otherwise create a combined callback | |
| 210 | typedef compose_cb_impl< | |
| 211 | typename util::decay<F1>::type, typename util::decay<F2>::type | |
| 212 | > result_type; | |
| 213 | return result_type(std::forward<F1>(f1), std::forward<F2>(f2)); | |
| 214 | } | |
| 215 | ||
| 216 | /////////////////////////////////////////////////////////////////////////// | |
| 217 | struct handle_continuation_recursion_count | |
| 218 | { | |
| 219 | handle_continuation_recursion_count() | |
| 220 | : count_(threads::get_continuation_recursion_count()) | |
| 221 | { | |
| 222 | ++count_; | |
| 223 | } | |
| 224 | ~handle_continuation_recursion_count() | |
| 225 | { | |
| 226 | --count_; | |
| 227 | } | |
| 228 | ||
| 229 | std::size_t& count_; | |
| 230 | }; | |
| 231 | ||
| 232 | /////////////////////////////////////////////////////////////////////////// | |
| 233 | HPX_EXPORT bool run_on_completed_on_new_thread( | |
| 234 | util::unique_function_nonser<bool()> && f, error_code& ec); | |
| 235 | ||
| 236 | /////////////////////////////////////////////////////////////////////////// | |
| 237 | template <typename Result> | |
| 238 | struct future_data : future_data_refcnt_base | |
| 239 | { | |
| 240 | HPX_NON_COPYABLE(future_data); | |
| 241 | ||
| 242 | typedef typename future_data_result<Result>::type result_type; | |
| 243 | typedef util::unique_function_nonser<void()> completed_callback_type; | |
| 244 | typedef lcos::local::spinlock mutex_type; | |
| 245 | ||
| 246 | enum state | |
| 247 | { | |
| 248 | empty = 0, | |
| 249 | ready = 1, | |
| 250 | value = 2 | ready, | |
| 251 | exception = 4 | ready | |
| 252 | }; | |
| 253 | ||
| 254 | public: | |
| 255 | future_data() | |
| 256 | : state_(empty) | |
| 257 | {} | |
| 258 | ||
| 259 | ~future_data() | |
| 260 | { | |
| 261 | reset(); | |
| 262 | } | |
| 263 | ||
| 264 | virtual void execute_deferred(error_code& ec = throws) {} | |
| 265 | ||
| 266 | // cancellation is disabled by default | |
| 267 | virtual bool cancelable() const | |
| 268 | { | |
| 269 | return false; | |
| 270 | } | |
| 271 | virtual void cancel() | |
| 272 | { | |
| 273 | HPX_THROW_EXCEPTION(future_does_not_support_cancellation, | |
| 274 | "future_data::cancel", | |
| 275 | "this future does not support cancellation"); | |
| 276 | } | |
| 277 | ||
| 278 | /// Get the result of the requested action. This call blocks (yields | |
| 279 | /// control) if the result is not ready. As soon as the result has been | |
| 280 | /// returned and the waiting thread has been re-scheduled by the thread | |
| 281 | /// manager the function will return. | |
| 282 | /// | |
| 283 | /// \param ec [in,out] this represents the error status on exit, | |
| 284 | /// if this is pre-initialized to \a hpx#throws | |
| 285 | /// the function will throw on error instead. If the | |
| 286 | /// operation blocks and is aborted because the object | |
| 287 | /// went out of scope, the code \a hpx#yield_aborted is | |
| 288 | /// set or thrown. | |
| 289 | /// | |
| 290 | /// \note If there has been an error reported (using the action | |
| 291 | /// \a base_lco#set_exception), this function will throw an | |
| 292 | /// exception encapsulating the reported error code and | |
| 293 | /// error description if <code>&ec == &throws</code>. | |
| 294 | virtual result_type* get_result(error_code& ec = throws) | |
| 295 | { | |
| 296 | // yields control if needed | |
| 297 | wait(ec); | |
| 298 | if (ec) return nullptr; | |
| 299 | ||
| 300 | // No locking is required. Once a future has been made ready, which | |
| 301 | // is a postcondition of wait, either: | |
| 302 | // | |
| 303 | // - there is only one writer (future), or | |
| 304 | // - there are multiple readers only (shared_future, lock hurts | |
| 305 | // concurrency) | |
| 306 | ||
| 307 | if (state_ == empty) { | |
| 308 | // the value has already been moved out of this future | |
| 309 | HPX_THROWS_IF(ec, no_state, | |
| 310 | "future_data::get_result", | |
| 311 | "this future has no valid shared state"); | |
| 312 | return nullptr; | |
| 313 | } | |
| 314 | ||
| 315 | // the thread has been re-activated by one of the actions | |
| 316 | // supported by this promise (see promise::set_event | |
| 317 | // and promise::set_exception). | |
| 318 | if (state_ == exception) | |
| 319 | { | |
| 320 | boost::exception_ptr* exception_ptr = | |
| 321 | reinterpret_cast<boost::exception_ptr*>(&storage_); | |
| 322 | // an error has been reported in the meantime, throw or set | |
| 323 | // the error code | |
| 324 | if (&ec == &throws) { | |
| 325 | boost::rethrow_exception(*exception_ptr); | |
| 326 | // never reached | |
| 327 | } | |
| 328 | else { | |
| 329 | ec = make_error_code(*exception_ptr); | |
| 330 | } | |
| 331 | return nullptr; | |
| 332 | } | |
| 333 | return reinterpret_cast<result_type*>(&storage_); | |
| 334 | } | |
| 335 | ||
| 336 | // deferred execution of a given continuation | |
| 337 | bool run_on_completed(completed_callback_type && on_completed, | |
| 338 | boost::exception_ptr& ptr) | |
| 339 | { | |
| 340 | try { | |
| 341 | on_completed(); | |
| 342 | } | |
| 343 | catch (...) { | |
| 344 | ptr = boost::current_exception(); | |
| 345 | return false; | |
| 346 | } | |
| 347 | return true; | |
| 348 | } | |
| 349 | ||
| 350 | // make sure continuation invocation does not recurse deeper than | |
| 351 | // allowed | |
| 352 | void handle_on_completed(completed_callback_type && on_completed) | |
| 353 | { | |
| 354 | // We need to run the completion on a new thread if we are on a | |
| 355 | // non HPX thread. | |
| 356 | bool recurse_asynchronously = hpx::threads::get_self_ptr() == nullptr; | |
| 357 | #if defined(HPX_HAVE_THREADS_GET_STACK_POINTER) | |
| 358 | recurse_asynchronously = | |
| 359 | !this_thread::has_sufficient_stack_space(); | |
| 360 | #else | |
| 361 | handle_continuation_recursion_count cnt; | |
| 362 | recurse_asynchronously = recurse_asynchronously || | |
| 363 | cnt.count_ > HPX_CONTINUATION_MAX_RECURSION_DEPTH; | |
| 364 | #endif | |
| 365 | if (!recurse_asynchronously) | |
| 366 | { | |
| 367 | // directly execute continuation on this thread | |
| 368 | on_completed(); | |
| 369 | } | |
| 370 | else | |
| 371 | { | |
| 372 | // re-spawn continuation on a new thread | |
| 373 | boost::intrusive_ptr<future_data> this_(this); | |
| 374 | ||
| 375 | error_code ec(lightweight); | |
| 376 | boost::exception_ptr ptr; | |
| 377 | if (!run_on_completed_on_new_thread( | |
| 378 | util::deferred_call(&future_data::run_on_completed, | |
| 379 | std::move(this_), std::move(on_completed), | |
| 380 | std::ref(ptr)), | |
| 381 | ec)) | |
| 382 | { | |
| 383 | // thread creation went wrong | |
| 384 | if (ec) { | |
| 385 | set_exception(hpx::detail::access_exception(ec)); | |
| 386 | return; | |
| 387 | } | |
| 388 | ||
| 389 | // re-throw exception in this context | |
| 390 | HPX_ASSERT(ptr); // exception should have been set | |
| 391 | boost::rethrow_exception(ptr); | |
| 392 | } | |
| 393 | } | |
| 394 | } | |
| 395 | ||
| 396 | /// Set the result of the requested action. | |
| 397 | template <typename Target> | |
| 398 | void set_value(Target && data, error_code& ec = throws) | |
| 399 | { | |
| 400 | std::unique_lock<mutex_type> l(this->mtx_); | |
| 401 | ||
| 402 | // check whether the data has already been set | |
| 403 | if (is_ready_locked()) { | |
| 404 | l.unlock(); | |
| 405 | HPX_THROWS_IF(ec, promise_already_satisfied, | |
| 406 | "future_data::set_value", | |
| 407 | "data has already been set for this future"); | |
| 408 | return; | |
| 409 | } | |
| 410 | ||
| 411 | completed_callback_type on_completed; | |
| 412 | ||
| 413 | on_completed = std::move(this->on_completed_); | |
| 414 | ||
| 415 | // set the data | |
| 416 | result_type* value_ptr = | |
| 417 | reinterpret_cast<result_type*>(&storage_); | |
| 418 | ::new ((void*)value_ptr) result_type( | |
| 419 | future_data_result<Result>::set(std::forward<Target>(data))); | |
| 420 | state_ = value; | |
| 421 | ||
| 422 | // handle all threads waiting for the future to become ready | |
| 423 | cond_.notify_all(std::move(l), ec); | |
| 424 | ||
| 425 | // Note: cv.notify_all() above 'consumes' the lock 'l' and leaves | |
| 426 | // it unlocked when returning. | |
| 427 | ||
| 428 | // invoke the callback (continuation) function | |
| 429 | if (on_completed) | |
| 430 | handle_on_completed(std::move(on_completed)); | |
| 431 | } | |
| 432 | ||
| 433 | template <typename Target> | |
| 434 | void set_exception(Target && data, error_code& ec = throws) | |
| 435 | { | |
| 436 | std::unique_lock<mutex_type> l(this->mtx_); | |
| 437 | ||
| 438 | // check whether the data has already been set | |
| 439 | if (is_ready_locked()) { | |
| 440 | l.unlock(); | |
| 441 | HPX_THROWS_IF(ec, promise_already_satisfied, | |
| 442 | "future_data::set_exception", | |
| 443 | "data has already been set for this future"); | |
| 444 | return; | |
| 445 | } | |
| 446 | ||
| 447 | completed_callback_type on_completed; | |
| 448 | ||
| 449 | on_completed = std::move(this->on_completed_); | |
| 450 | ||
| 451 | // set the data | |
| 452 | boost::exception_ptr* exception_ptr = | |
| 453 | reinterpret_cast<boost::exception_ptr*>(&storage_); | |
| 454 | ::new ((void*)exception_ptr) boost::exception_ptr( | |
| 455 | std::forward<Target>(data)); | |
| 456 | state_ = exception; | |
| 457 | ||
| 458 | // handle all threads waiting for the future to become ready | |
| 459 | cond_.notify_all(std::move(l), ec); | |
| 460 | ||
| 461 | // Note: cv.notify_all() above 'consumes' the lock 'l' and leaves | |
| 462 | // it unlocked when returning. | |
| 463 | ||
| 464 | // invoke the callback (continuation) function | |
| 465 | if (on_completed) | |
| 466 | handle_on_completed(std::move(on_completed)); | |
| 467 | } | |
| 468 | ||
| 469 | // helper functions for setting data (if successful) or the error (if | |
| 470 | // non-successful) | |
| 471 | template <typename T> | |
| 472 | void set_data(T && result) | |
| 473 | { | |
| 474 | // set the received result, reset error status | |
| 475 | try { | |
| 476 | typedef typename util::decay<T>::type naked_type; | |
| 477 | ||
| 478 | typedef traits::get_remote_result< | |
| 479 | result_type, naked_type | |
| 480 | > get_remote_result_type; | |
| 481 | ||
| 482 | // store the value | |
| 483 | set_value(std::move(get_remote_result_type::call( | |
| 484 | std::forward<T>(result)))); | |
| 485 | } | |
| 486 | catch (...) { | |
| 487 | // store the error instead | |
| 488 | return set_exception(boost::current_exception()); | |
| 489 | } | |
| 490 | } | |
| 491 | ||
| 492 | // trigger the future with the given error condition | |
| 493 | void set_error(error e, char const* f, char const* msg) | |
| 494 | { | |
| 495 | try { | |
| 496 | HPX_THROW_EXCEPTION(e, f, msg); | |
| 497 | } | |
| 498 | catch (...) { | |
| 499 | // store the error code | |
| 500 | set_exception(boost::current_exception()); | |
| 501 | } | |
| 502 | } | |
| 503 | ||
| 504 | /// Reset the promise to allow to restart an asynchronous | |
| 505 | /// operation. Allows any subsequent set_data operation to succeed. | |
| 506 | void reset(error_code& /*ec*/ = throws) | |
| 507 | { | |
| 508 | // no locking is required as semantics guarantee a single writer | |
| 509 | // and no reader | |
| 510 | ||
| 511 | // release any stored data and callback functions | |
| 512 | switch (state_) { | |
| 513 | case value: | |
| 514 | { | |
| 515 | result_type* value_ptr = | |
| 516 | reinterpret_cast<result_type*>(&storage_); | |
| 517 | value_ptr->~result_type(); | |
| 518 | break; | |
| 519 | } | |
| 520 | case exception: | |
| 521 | { | |
| 522 | boost::exception_ptr* exception_ptr = | |
| 523 | reinterpret_cast<boost::exception_ptr*>(&storage_); | |
| 524 | exception_ptr->~exception_ptr(); | |
| 525 | break; | |
| 526 | } | |
| 527 | default: break; | |
| 528 | } | |
| 529 | ||
| 530 | state_ = empty; | |
| 531 | on_completed_ = completed_callback_type(); | |
| 532 | } | |
| 533 | ||
| 534 | // continuation support | |
| 535 | ||
| 536 | /// Set the callback which needs to be invoked when the future becomes | |
| 537 | /// ready. If the future is ready the function will be invoked | |
| 538 | /// immediately. | |
| 539 | void set_on_completed(completed_callback_type data_sink) | |
| 540 | { | |
| 541 | if (!data_sink) return; | |
| 542 | ||
| 543 | std::unique_lock<mutex_type> l(this->mtx_); | |
| 544 | ||
| 545 | if (is_ready_locked()) { | |
| 546 | ||
| 547 | HPX_ASSERT(!on_completed_); | |
| 548 | ||
| 549 | // invoke the callback (continuation) function right away | |
| 550 | l.unlock(); | |
| 551 | ||
| 552 | handle_on_completed(std::move(data_sink)); | |
| 553 | } | |
| 554 | else { | |
| 555 | // store a combined callback wrapping the old and the new one | |
| 556 | this->on_completed_ = compose_cb( | |
| 557 | std::move(data_sink), std::move(on_completed_)); | |
| 558 | } | |
| 559 | } | |
| 560 | ||
| 561 | virtual void wait(error_code& ec = throws) | |
| 562 | { | |
| 563 | std::unique_lock<mutex_type> l(mtx_); | |
| 564 | ||
| 565 | // block if this entry is empty | |
| 566 | if (state_ == empty) { | |
| 567 | cond_.wait(l, "future_data::wait", ec); | |
| 568 | if (ec) return; | |
| 569 | } | |
| 570 | ||
| 571 | if (&ec != &throws) | |
| 572 | ec = make_success_code(); | |
| 573 | } | |
| 574 | ||
| 575 | virtual future_status | |
| 576 | wait_until(util::steady_clock::time_point const& abs_time, | |
| 577 | error_code& ec = throws) | |
| 578 | { | |
| 579 | std::unique_lock<mutex_type> l(mtx_); | |
| 580 | ||
| 581 | // block if this entry is empty | |
| 582 | if (state_ == empty) { | |
| 583 | threads::thread_state_ex_enum const reason = | |
| 584 | cond_.wait_until(l, abs_time, | |
| 585 | "future_data::wait_until", ec); | |
| 586 | if (ec) return future_status::uninitialized; | |
| 587 | ||
| 588 | if (reason == threads::wait_timeout) | |
| 589 | return future_status::timeout; | |
| 590 | ||
| 591 | return future_status::ready; | |
| 592 | } | |
| 593 | ||
| 594 | if (&ec != &throws) | |
| 595 | ec = make_success_code(); | |
| 596 | ||
| 597 | return future_status::ready; //-V110 | |
| 598 | } | |
| 599 | ||
| 600 | /// Return whether or not the data is available for this | |
| 601 | /// \a future. | |
| 602 | bool is_ready() const | |
| 603 | { | |
| 604 | std::unique_lock<mutex_type> l(mtx_); | |
| 605 | return is_ready_locked(); | |
| 606 | } | |
| 607 | ||
| 608 | bool is_ready_locked() const | |
| 609 | { | |
| 610 | return (state_ & ready) != 0; | |
| 611 | } | |
| 612 | ||
| 613 | bool has_value() const | |
| 614 | { | |
| 615 | std::unique_lock<mutex_type> l(mtx_); | |
| 616 | return state_ == value; | |
| 617 | } | |
| 618 | ||
| 619 | bool has_exception() const | |
| 620 | { | |
| 621 | std::unique_lock<mutex_type> l(mtx_); | |
| 622 | return state_ == exception; | |
| 623 | } | |
| 624 | ||
| 625 | protected: | |
| 626 | mutable mutex_type mtx_; | |
| 627 | completed_callback_type on_completed_; | |
| 628 | ||
| 629 | private: | |
| 630 | local::detail::condition_variable cond_; // threads waiting in read | |
| 631 | state state_; // current state | |
| 632 | typename future_data_storage<Result>::type storage_; | |
| 633 | }; | |
| 634 | ||
| 635 | /////////////////////////////////////////////////////////////////////////// | |
| 636 | template <typename Result> | |
| 637 | struct timed_future_data : future_data<Result> | |
| 638 | { | |
| 639 | public: | |
| 640 | typedef future_data<Result> base_type; | |
| 641 | typedef typename base_type::result_type result_type; | |
| 642 | typedef typename base_type::mutex_type mutex_type; | |
| 643 | ||
| 644 | public: | |
| 645 | timed_future_data() {} | |
| 646 | ||
| 647 | template <typename Result_> | |
| 648 | timed_future_data( | |
| 649 | util::steady_clock::time_point const& abs_time, | |
| 650 | Result_&& init) | |
| 651 | { | |
| 652 | boost::intrusive_ptr<timed_future_data> this_(this); | |
| 653 | ||
| 654 | error_code ec; | |
| 655 | threads::thread_id_type id = threads::register_thread_nullary( | |
| 656 | util::bind(util::one_shot(&timed_future_data::set_value), | |
| 657 | std::move(this_), | |
| 658 | future_data_result<Result>::set(std::forward<Result_>(init))), | |
| 659 | "timed_future_data<Result>::timed_future_data", | |
| 660 | threads::suspended, true, threads::thread_priority_normal, | |
| 661 | std::size_t(-1), threads::thread_stacksize_default, ec); | |
| 662 | if (ec) { | |
| 663 | // thread creation failed, report error to the new future | |
| 664 | this->base_type::set_exception(hpx::detail::access_exception(ec)); | |
| 665 | } | |
| 666 | ||
| 667 | // start new thread at given point in time | |
| 668 | threads::set_thread_state(id, abs_time, threads::pending, | |
| 669 | threads::wait_timeout, threads::thread_priority_boost, ec); | |
| 670 | if (ec) { | |
| 671 | // thread scheduling failed, report error to the new future | |
| 672 | this->base_type::set_exception(hpx::detail::access_exception(ec)); | |
| 673 | } | |
| 674 | } | |
| 675 | ||
| 676 | void set_value(result_type const& value) | |
| 677 | { | |
| 678 | this->base_type::set_value(value); | |
| 679 | } | |
| 680 | }; | |
| 681 | ||
| 682 | /////////////////////////////////////////////////////////////////////////// | |
| 683 | template <typename Result> | |
| 684 | struct task_base : future_data<Result> | |
| 685 | { | |
| 686 | protected: | |
| 687 | typedef typename future_data<Result>::mutex_type mutex_type; | |
| 688 | typedef boost::intrusive_ptr<task_base> future_base_type; | |
| 689 | typedef typename future_data<Result>::result_type result_type; | |
| 690 | ||
| 691 | public: | |
| 692 | task_base() | |
| 693 | : started_(false), sched_(nullptr) | |
| 694 | {} | |
| 695 | ||
| 696 | task_base(threads::executor& sched) | |
| 697 | : started_(false), | |
| 698 | sched_(sched ? &sched : nullptr) | |
| 699 | {} | |
| 700 | ||
| 701 | virtual void execute_deferred(error_code& ec = throws) | |
| 702 | { | |
| 703 | if (!started_test_and_set()) | |
| 704 | this->do_run(); | |
| 705 | } | |
| 706 | ||
| 707 | // retrieving the value | |
| 708 | virtual result_type* get_result(error_code& ec = throws) | |
| 709 | { | |
| 710 | if (!started_test_and_set()) | |
| 711 | this->do_run(); | |
| 712 | return this->future_data<Result>::get_result(ec); | |
| 713 | } | |
| 714 | ||
| 715 | // wait support | |
| 716 | virtual void wait(error_code& ec = throws) | |
| 717 | { | |
| 718 | if (!started_test_and_set()) | |
| 719 | this->do_run(); | |
| 720 | this->future_data<Result>::wait(ec); | |
| 721 | } | |
| 722 | ||
| 723 | virtual future_status | |
| 724 | wait_until(util::steady_clock::time_point const& abs_time, | |
| 725 | error_code& ec = throws) | |
| 726 | { | |
| 727 | if (!started_test()) | |
| 728 | return future_status::deferred; //-V110 | |
| 729 | return this->future_data<Result>::wait_until(abs_time, ec); | |
| 730 | } | |
| 731 | ||
| 732 | private: | |
| 733 | bool started_test() const | |
| 734 | { | |
| 735 | std::lock_guard<mutex_type> l(this->mtx_); | |
| 736 | return started_; | |
| 737 | } | |
| 738 | ||
| 739 | bool started_test_and_set() | |
| 740 | { | |
| 741 | std::lock_guard<mutex_type> l(this->mtx_); | |
| 742 | if (started_) | |
| 743 | return true; | |
| 744 | ||
| 745 | started_ = true; | |
| 746 | return false; | |
| 747 | } | |
| 748 | ||
| 749 | protected: | |
| 750 | void check_started() | |
| 751 | { | |
| 752 | std::lock_guard<mutex_type> l(this->mtx_); | |
| 753 | if (started_) { | |
| 754 | HPX_THROW_EXCEPTION(task_already_started, | |
| 755 | "task_base::check_started", | |
| 756 | "this task has already been started"); | |
| 757 | return; | |
| 758 | } | |
| 759 | started_ = true; | |
| 760 | } | |
| 761 | ||
| 762 | public: | |
| 763 | // run synchronously | |
| 764 | void run() | |
| 765 | { | |
| 766 | check_started(); | |
| 767 | this->do_run(); // always on this thread | |
| 768 | } | |
| 769 | ||
| 770 | // run in a separate thread | |
| 771 | virtual threads::thread_id_type apply(launch policy, | |
| 772 | threads::thread_priority priority, | |
| 773 | threads::thread_stacksize stacksize, error_code& ec) | |
| 774 | { | |
| 775 | HPX_ASSERT(false); // shouldn't ever be called | |
| 776 | return threads::invalid_thread_id; | |
| 777 | } | |
| 778 | ||
| 779 | protected: | |
| 780 | static threads::thread_result_type run_impl(future_base_type this_) | |
| 781 | { | |
| 782 | this_->do_run(); | |
| 783 | return threads::thread_result_type(threads::terminated, nullptr); | |
| 784 | } | |
| 785 | ||
| 786 | public: | |
| 787 | template <typename T> | |
| 788 | void set_data(T && result) | |
| 789 | { | |
| 790 | this->future_data<Result>::set_data(std::forward<T>(result)); | |
| 791 | } | |
| 792 | ||
| 793 | void set_exception( | |
| 794 | boost::exception_ptr const& e, error_code& ec = throws) | |
| 795 | { | |
| 796 | this->future_data<Result>::set_exception(e, ec); | |
| 797 | } | |
| 798 | ||
| 799 | virtual void do_run() | |
| 800 | { | |
| 801 | HPX_ASSERT(false); // shouldn't ever be called | |
| 802 | } | |
| 803 | ||
| 804 | protected: | |
| 805 | bool started_; | |
| 806 | threads::executor* sched_; | |
| 807 | }; | |
| 808 | ||
| 809 | /////////////////////////////////////////////////////////////////////////// | |
| 810 | template <typename Result> | |
| 811 | struct cancelable_task_base : task_base<Result> | |
| 812 | { | |
| 813 | protected: | |
| 814 | typedef typename task_base<Result>::mutex_type mutex_type; | |
| 815 | typedef boost::intrusive_ptr<cancelable_task_base> future_base_type; | |
| 816 | typedef typename future_data<Result>::result_type result_type; | |
| 817 | ||
| 818 | protected: | |
| 819 | threads::thread_id_type get_thread_id() const | |
| 820 | { | |
| 821 | std::lock_guard<mutex_type> l(this->mtx_); | |
| 822 | return id_; | |
| 823 | } | |
| 824 | void set_thread_id(threads::thread_id_type id) | |
| 825 | { | |
| 826 | std::lock_guard<mutex_type> l(this->mtx_); | |
| 827 | id_ = id; | |
| 828 | } | |
| 829 | ||
| 830 | public: | |
| 831 | cancelable_task_base() | |
| 832 | : task_base<Result>(), id_(threads::invalid_thread_id) | |
| 833 | {} | |
| 834 | ||
| 835 | cancelable_task_base(threads::executor& sched) | |
| 836 | : task_base<Result>(sched), id_(threads::invalid_thread_id) | |
| 837 | {} | |
| 838 | ||
| 839 | private: | |
| 840 | struct reset_id | |
| 841 | { | |
| 842 | reset_id(cancelable_task_base& target) | |
| 843 | : target_(target) | |
| 844 | { | |
| 845 | target.set_thread_id(threads::get_self_id()); | |
| 846 | } | |
| 847 | ~reset_id() | |
| 848 | { | |
| 849 | target_.set_thread_id(threads::invalid_thread_id); | |
| 850 | } | |
| 851 | cancelable_task_base& target_; | |
| 852 | }; | |
| 853 | ||
| 854 | protected: | |
| 855 | static threads::thread_result_type run_impl(future_base_type this_) | |
| 856 | { | |
| 857 | reset_id r(*this_); | |
| 858 | this_->do_run(); | |
| 859 | return threads::thread_result_type(threads::terminated, nullptr); | |
| 860 | } | |
| 861 | ||
| 862 | public: | |
| 863 | // cancellation support | |
| 864 | bool cancelable() const | |
| 865 | { | |
| 866 | return true; | |
| 867 | } | |
| 868 | ||
| 869 | void cancel() | |
| 870 | { | |
| 871 | std::unique_lock<mutex_type> l(this->mtx_); | |
| 872 | try { | |
| 873 | if (!this->started_) | |
| 874 | HPX_THROW_THREAD_INTERRUPTED_EXCEPTION(); | |
| 875 | ||
| 876 | if (this->is_ready_locked()) | |
| 877 | return; // nothing we can do | |
| 878 | ||
| 879 | if (id_ != threads::invalid_thread_id) { | |
| 880 | // interrupt the executing thread | |
| 881 | threads::interrupt_thread(id_); | |
| 882 | ||
| 883 | this->started_ = true; | |
| 884 | ||
| 885 | l.unlock(); | |
| 886 | this->set_error(future_cancelled, | |
| 887 | "task_base<Result>::cancel", | |
| 888 | "future has been canceled"); | |
| 889 | } | |
| 890 | else { | |
| 891 | HPX_THROW_EXCEPTION(future_can_not_be_cancelled, | |
| 892 | "task_base<Result>::cancel", | |
| 893 | "future can't be canceled at this time"); | |
| 894 | } | |
| 895 | } | |
| 896 | catch (...) { | |
| 897 | this->started_ = true; | |
| 898 | this->set_exception(boost::current_exception()); | |
| 899 | throw; | |
| 900 | } | |
| 901 | } | |
| 902 | ||
| 903 | protected: | |
| 904 | threads::thread_id_type id_; | |
| 905 | }; | |
| 906 | }}} | |
| 907 | ||
| 908 | #endif | |
| 909 |
Copyright (c) 2006-2012 Rogue Wave Software, Inc. All Rights Reserved.
Patents pending.