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28 #ifndef __BASE_FIBER_HH__
29 #define __BASE_FIBER_HH__
31 // ucontext functions (like getcontext, setcontext etc) have been marked
32 // as deprecated and are hence hidden in latest macOS releases.
33 // By defining _XOPEN_SOURCE we make them available at compilation time.
34 #if defined(__APPLE__) && defined(__MACH__)
35 #define _XOPEN_SOURCE 600
42 // Avoid fortify source for longjmp to work between ucontext stacks.
43 #pragma push_macro("__USE_FORTIFY_LEVEL")
44 #undef __USE_FORTIFY_LEVEL
46 #pragma pop_macro("__USE_FORTIFY_LEVEL")
51 #include "config/have_valgrind.hh"
54 * This class represents a fiber, which is a light weight sort of thread which
55 * is cooperatively scheduled and runs sequentially with other fibers, swapping
56 * in and out of a single actual thread of execution.
58 * To define your own threads, create a subclass of Fiber and override its
59 * main() function to do what you want your fiber to do. You can start it by
60 * calling its run() method which will stop your execution and start the other
61 * fiber in your place.
63 * If your main() function ends, that fiber will automatically switch to either
64 * the primary fiber, or to a particular fiber you specified at construction
65 * time, and your fiber is considered finished.
74 const static size_t DefaultStackSize = 0x50000;
77 * @param Link points to another fiber which will start executing when this
78 * fiber's main function returns.
79 * @param stack_size is the size of the stack available to this fiber.
84 Fiber(size_t stack_size=DefaultStackSize);
85 Fiber(Fiber *link, size_t stack_size=DefaultStackSize);
86 /** @} */ // end of api_fiber
94 * Start executing the fiber represented by this object. This function
95 * will "return" when the current fiber is switched back to later on.
102 * Returns whether the "main" function of this fiber has finished.
106 bool finished() const { return _finished; };
109 * Returns whether the "main" function of this fiber has started.
113 bool started() const { return _started; };
116 * Get a pointer to the current running Fiber.
120 static Fiber *currentFiber();
123 * Get a pointer to the primary Fiber.
124 * This Fiber represents the thread of execution started by the OS, and
125 * which has a Fiber attached to it after the fact.
129 static Fiber *primaryFiber();
133 * This method is called when this fiber is first run. Override it to
134 * give your fiber something to do. When main returns, the fiber will
135 * mark itself as finished and switch to its link fiber.
137 virtual void main() = 0;
139 void setStarted() { _started = true; }
142 static void entryTrampoline();
146 // ucontext is slow in swapcontext. Here we use _setjmp/_longjmp to avoid
147 // the additional signals for speed up.
152 // The stack for this context, or a nullptr if allocated elsewhere.
156 size_t guardPageSize;
158 unsigned valgrindStackId;
163 void createContext();
166 #endif // __BASE_FIBER_HH__