2 * Copyright 2015 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
20 #include <folly/Memory.h>
21 #include <folly/Optional.h>
22 #include <folly/Portability.h>
23 #include <folly/ScopeGuard.h>
24 #include <folly/experimental/fibers/Baton.h>
25 #include <folly/experimental/fibers/Fiber.h>
26 #include <folly/experimental/fibers/Promise.h>
27 #include <folly/experimental/fibers/LoopController.h>
28 #include <folly/futures/Try.h>
30 namespace folly { namespace fibers {
32 inline void FiberManager::ensureLoopScheduled() {
33 if (isLoopScheduled_) {
37 isLoopScheduled_ = true;
38 loopController_->schedule();
41 inline void FiberManager::runReadyFiber(Fiber* fiber) {
42 assert(fiber->state_ == Fiber::NOT_STARTED ||
43 fiber->state_ == Fiber::READY_TO_RUN);
44 currentFiber_ = fiber;
46 while (fiber->state_ == Fiber::NOT_STARTED ||
47 fiber->state_ == Fiber::READY_TO_RUN) {
49 jumpContext(&mainContext_, &fiber->fcontext_, fiber->data_);
50 if (fiber->state_ == Fiber::AWAITING_IMMEDIATE) {
54 exceptionCallback_(std::current_exception(), "running immediateFunc_");
56 immediateFunc_ = nullptr;
57 fiber->state_ = Fiber::READY_TO_RUN;
61 if (fiber->state_ == Fiber::AWAITING) {
64 } else if (fiber->state_ == Fiber::INVALID) {
65 assert(fibersActive_ > 0);
67 // Making sure that task functor is deleted once task is complete.
68 // NOTE: we must do it on main context, as the fiber is not
69 // running at this point.
70 fiber->func_ = nullptr;
71 fiber->resultFunc_ = nullptr;
72 if (fiber->finallyFunc_) {
74 fiber->finallyFunc_();
76 exceptionCallback_(std::current_exception(), "running finallyFunc_");
78 fiber->finallyFunc_ = nullptr;
80 fiber->localData_.reset();
82 if (fibersPoolSize_ < options_.maxFibersPoolSize) {
83 fibersPool_.push_front(*fiber);
87 assert(fibersAllocated_ > 0);
91 currentFiber_ = nullptr;
94 inline bool FiberManager::loopUntilNoReady() {
96 isLoopScheduled_ = false;
97 currentFiberManager_ = nullptr;
100 currentFiberManager_ = this;
102 bool hadRemoteFiber = true;
103 while (hadRemoteFiber) {
104 hadRemoteFiber = false;
106 while (!readyFibers_.empty()) {
107 auto& fiber = readyFibers_.front();
108 readyFibers_.pop_front();
109 runReadyFiber(&fiber);
112 remoteReadyQueue_.sweep(
113 [this, &hadRemoteFiber] (Fiber* fiber) {
114 runReadyFiber(fiber);
115 hadRemoteFiber = true;
119 remoteTaskQueue_.sweep(
120 [this, &hadRemoteFiber] (RemoteTask* taskPtr) {
121 std::unique_ptr<RemoteTask> task(taskPtr);
122 auto fiber = getFiber();
123 if (task->localData) {
124 fiber->localData_ = *task->localData;
127 fiber->setFunction(std::move(task->func));
128 fiber->data_ = reinterpret_cast<intptr_t>(fiber);
129 runReadyFiber(fiber);
130 hadRemoteFiber = true;
135 return fibersActive_ > 0;
138 // We need this to be in a struct, not inlined in addTask, because clang crashes
140 template <typename F>
141 struct FiberManager::AddTaskHelper {
144 static constexpr bool allocateInBuffer =
145 sizeof(Func) <= Fiber::kUserBufferSize;
149 Func(F&& func, FiberManager& fm) :
150 func_(std::forward<F>(func)), fm_(fm) {}
156 fm_.exceptionCallback_(std::current_exception(),
157 "running Func functor");
159 if (allocateInBuffer) {
172 template <typename F>
173 void FiberManager::addTask(F&& func) {
174 typedef AddTaskHelper<F> Helper;
176 auto fiber = getFiber();
178 fiber->localData_ = currentFiber_->localData_;
181 if (Helper::allocateInBuffer) {
182 auto funcLoc = static_cast<typename Helper::Func*>(fiber->getUserBuffer());
183 new (funcLoc) typename Helper::Func(std::forward<F>(func), *this);
185 fiber->setFunction(std::ref(*funcLoc));
187 auto funcLoc = new typename Helper::Func(std::forward<F>(func), *this);
189 fiber->setFunction(std::ref(*funcLoc));
192 fiber->data_ = reinterpret_cast<intptr_t>(fiber);
193 readyFibers_.push_back(*fiber);
195 ensureLoopScheduled();
198 template <typename F>
199 void FiberManager::addTaskRemote(F&& func) {
201 auto currentFm = getFiberManagerUnsafe();
202 if (currentFm && currentFm->currentFiber_) {
203 return folly::make_unique<RemoteTask>(
204 std::forward<F>(func),
205 currentFm->currentFiber_->localData_);
207 return folly::make_unique<RemoteTask>(std::forward<F>(func));
209 if (remoteTaskQueue_.insertHead(task.release())) {
210 loopController_->scheduleThreadSafe();
214 template <typename X>
215 struct IsRvalueRefTry { static const bool value = false; };
216 template <typename T>
217 struct IsRvalueRefTry<folly::Try<T>&&> { static const bool value = true; };
219 // We need this to be in a struct, not inlined in addTaskFinally, because clang
220 // crashes otherwise.
221 template <typename F, typename G>
222 struct FiberManager::AddTaskFinallyHelper {
226 typedef typename std::result_of<F()>::type Result;
228 static constexpr bool allocateInBuffer =
229 sizeof(Func) + sizeof(Finally) <= Fiber::kUserBufferSize;
235 finally_(std::move(finally)),
241 finally_(std::move(*result_));
243 fm_.exceptionCallback_(std::current_exception(),
244 "running Finally functor");
247 if (allocateInBuffer) {
258 folly::Optional<folly::Try<Result>> result_;
264 Func(F&& func, Finally& finally) :
265 func_(std::move(func)), result_(finally.result_) {}
268 result_ = folly::makeTryFunction(std::move(func_));
270 if (allocateInBuffer) {
279 folly::Optional<folly::Try<Result>>& result_;
283 template <typename F, typename G>
284 void FiberManager::addTaskFinally(F&& func, G&& finally) {
285 typedef typename std::result_of<F()>::type Result;
288 IsRvalueRefTry<typename FirstArgOf<G>::type>::value,
289 "finally(arg): arg must be Try<T>&&");
293 typename std::remove_reference<
294 typename FirstArgOf<G>::type
295 >::type::element_type
297 "finally(Try<T>&&): T must be convertible from func()'s return type");
299 auto fiber = getFiber();
301 fiber->localData_ = currentFiber_->localData_;
304 typedef AddTaskFinallyHelper<F,G> Helper;
306 if (Helper::allocateInBuffer) {
307 auto funcLoc = static_cast<typename Helper::Func*>(
308 fiber->getUserBuffer());
309 auto finallyLoc = static_cast<typename Helper::Finally*>(
310 static_cast<void*>(funcLoc + 1));
312 new (finallyLoc) typename Helper::Finally(std::move(finally), *this);
313 new (funcLoc) typename Helper::Func(std::move(func), *finallyLoc);
315 fiber->setFunctionFinally(std::ref(*funcLoc), std::ref(*finallyLoc));
317 auto finallyLoc = new typename Helper::Finally(std::move(finally), *this);
318 auto funcLoc = new typename Helper::Func(std::move(func), *finallyLoc);
320 fiber->setFunctionFinally(std::ref(*funcLoc), std::ref(*finallyLoc));
323 fiber->data_ = reinterpret_cast<intptr_t>(fiber);
324 readyFibers_.push_back(*fiber);
326 ensureLoopScheduled();
329 template <typename F>
330 typename std::result_of<F()>::type
331 FiberManager::runInMainContext(F&& func) {
332 return runInMainContextHelper(std::forward<F>(func));
335 template <typename F>
336 inline typename std::enable_if<
337 !std::is_same<typename std::result_of<F()>::type, void>::value,
338 typename std::result_of<F()>::type>::type
339 FiberManager::runInMainContextHelper(F&& func) {
340 if (UNLIKELY(activeFiber_ == nullptr)) {
344 typedef typename std::result_of<F()>::type Result;
346 folly::Try<Result> result;
347 auto f = [&func, &result]() mutable {
348 result = folly::makeTryFunction(std::forward<F>(func));
351 immediateFunc_ = std::ref(f);
352 activeFiber_->preempt(Fiber::AWAITING_IMMEDIATE);
354 return std::move(result.value());
357 template <typename F>
358 inline typename std::enable_if<
359 std::is_same<typename std::result_of<F()>::type, void>::value,
361 FiberManager::runInMainContextHelper(F&& func) {
362 if (UNLIKELY(activeFiber_ == nullptr)) {
367 immediateFunc_ = std::ref(func);
368 activeFiber_->preempt(Fiber::AWAITING_IMMEDIATE);
371 inline FiberManager& FiberManager::getFiberManager() {
372 assert(currentFiberManager_ != nullptr);
373 return *currentFiberManager_;
376 inline FiberManager* FiberManager::getFiberManagerUnsafe() {
377 return currentFiberManager_;
380 inline bool FiberManager::hasActiveFiber() {
381 return activeFiber_ != nullptr;
384 template <typename T>
385 T& FiberManager::local() {
387 return currentFiber_->localData_.get<T>();
389 return localThread<T>();
392 template <typename T>
393 T& FiberManager::localThread() {
394 static thread_local T t;
398 template <typename F>
399 typename FirstArgOf<F>::type::value_type
400 inline await(F&& func) {
401 typedef typename FirstArgOf<F>::type::value_type Result;
403 folly::Try<Result> result;
406 baton.wait([&func, &result, &baton]() mutable {
407 func(Promise<Result>(result, baton));
410 return folly::moveFromTry(std::move(result));