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.
21 #include <boost/context/all.hpp>
22 #include <boost/version.hpp>
23 #include <folly/AtomicLinkedList.h>
24 #include <folly/IntrusiveList.h>
25 #include <folly/experimental/fibers/BoostContextCompatibility.h>
27 namespace folly { namespace fibers {
34 * @brief Fiber object used by FiberManager to execute tasks.
36 * Each Fiber object can be executing at most one task at a time. In active
37 * phase it is running the task function and keeps its context.
38 * Fiber is also used to pass data to blocked task and thus unblock it.
39 * Each Fiber may be associated with a single FiberManager.
44 * Sets data for the blocked task
46 * @param data this data will be returned by await() when task is resumed.
48 void setData(intptr_t data);
50 Fiber(const Fiber&) = delete;
51 Fiber& operator=(const Fiber&) = delete;
56 INVALID, /**< Does't have task function */
57 NOT_STARTED, /**< Has task function, not started */
58 READY_TO_RUN, /**< Was started, blocked, then unblocked */
59 RUNNING, /**< Is running right now */
60 AWAITING, /**< Is currently blocked */
61 AWAITING_IMMEDIATE, /**< Was preempted to run an immediate function,
62 and will be resumed right away */
65 State state_{INVALID}; /**< current Fiber state */
68 friend class FiberManager;
70 explicit Fiber(FiberManager& fiberManager);
73 void setFunction(F&& func);
75 template <typename F, typename G>
76 void setFunctionFinally(F&& func, G&& finally);
78 static void fiberFuncHelper(intptr_t fiber);
82 * Switch out of fiber context into the main context,
83 * performing necessary housekeeping for the new state.
85 * @param state New state, must not be RUNNING.
87 * @return The value passed back from the main context.
89 intptr_t preempt(State state);
92 * Examines how much of the stack we used at this moment and
93 * registers with the FiberManager (for monitoring).
95 void recordStackPosition();
97 FiberManager& fiberManager_; /**< Associated FiberManager */
98 FContext fcontext_; /**< current task execution context */
99 intptr_t data_; /**< Used to keep some data with the Fiber */
100 std::function<void()> func_; /**< task function */
103 * Points to next fiber in remote ready list
105 folly::AtomicLinkedListHook<Fiber> nextRemoteReady_;
107 static constexpr size_t kUserBufferSize = 256;
108 std::aligned_storage<kUserBufferSize>::type userBuffer_;
110 void* getUserBuffer();
112 std::function<void()> resultFunc_;
113 std::function<void()> finallyFunc_;
118 LocalData(const LocalData& other);
119 LocalData& operator=(const LocalData& other);
121 template <typename T>
127 static void* allocateHeapBuffer(size_t size);
128 static void freeHeapBuffer(void* buffer);
130 template <typename T>
131 static void dataCopyConstructor(void*, const void*);
132 template <typename T>
133 static void dataBufferDestructor(void*);
134 template <typename T>
135 static void dataHeapDestructor(void*);
137 static constexpr size_t kBufferSize = 128;
138 std::aligned_storage<kBufferSize>::type buffer_;
141 const std::type_info* dataType_;
142 void (*dataDestructor_)(void*);
143 void (*dataCopyConstructor_)(void*, const void*);
144 void* data_{nullptr};
147 LocalData localData_;
149 folly::IntrusiveListHook listHook_; /**< list hook for different FiberManager
156 #include <folly/experimental/fibers/Fiber-inl.h>