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 <boost/context/all.hpp>
21 #include <boost/version.hpp>
22 #include <folly/AtomicLinkedList.h>
23 #include <folly/IntrusiveList.h>
24 #include <folly/experimental/fibers/BoostContextCompatibility.h>
26 namespace folly { namespace fibers {
33 * @brief Fiber object used by FiberManager to execute tasks.
35 * Each Fiber object can be executing at most one task at a time. In active
36 * phase it is running the task function and keeps its context.
37 * Fiber is also used to pass data to blocked task and thus unblock it.
38 * Each Fiber may be associated with a single FiberManager.
43 * Sets data for the blocked task
45 * @param data this data will be returned by await() when task is resumed.
47 void setData(intptr_t data);
49 Fiber(const Fiber&) = delete;
50 Fiber& operator=(const Fiber&) = delete;
55 INVALID, /**< Does't have task function */
56 NOT_STARTED, /**< Has task function, not started */
57 READY_TO_RUN, /**< Was started, blocked, then unblocked */
58 RUNNING, /**< Is running right now */
59 AWAITING, /**< Is currently blocked */
60 AWAITING_IMMEDIATE, /**< Was preempted to run an immediate function,
61 and will be resumed right away */
64 State state_{INVALID}; /**< current Fiber state */
67 friend class FiberManager;
69 explicit Fiber(FiberManager& fiberManager);
72 void setFunction(F&& func);
74 template <typename F, typename G>
75 void setFunctionFinally(F&& func, G&& finally);
78 void setReadyFunction(G&& func);
80 static void fiberFuncHelper(intptr_t fiber);
84 * Switch out of fiber context into the main context,
85 * performing necessary housekeeping for the new state.
87 * @param state New state, must not be RUNNING.
89 * @return The value passed back from the main context.
91 intptr_t preempt(State state);
94 * Examines how much of the stack we used at this moment and
95 * registers with the FiberManager (for monitoring).
97 void recordStackPosition();
99 FiberManager& fiberManager_; /**< Associated FiberManager */
100 FContext fcontext_; /**< current task execution context */
101 intptr_t data_; /**< Used to keep some data with the Fiber */
102 std::function<void()> func_; /**< task function */
103 std::function<void()> readyFunc_; /**< function to be executed before jumping
107 * Points to next fiber in remote ready list
109 folly::AtomicLinkedListHook<Fiber> nextRemoteReady_;
111 static constexpr size_t kUserBufferSize = 256;
112 std::aligned_storage<kUserBufferSize>::type userBuffer_;
114 void* getUserBuffer();
116 std::function<void()> resultFunc_;
117 std::function<void()> finallyFunc_;
119 folly::IntrusiveListHook listHook_; /**< list hook for different FiberManager
126 #include <folly/experimental/fibers/Fiber-inl.h>