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30 #ifndef __BASE_FIBER_HH__
31 #define __BASE_FIBER_HH__
33 // ucontext functions (like getcontext, setcontext etc) have been marked
34 // as deprecated and are hence hidden in latest macOS releases.
35 // By defining _XOPEN_SOURCE we make them available at compilation time.
36 #if defined(__APPLE__) && defined(__MACH__)
37 #define _XOPEN_SOURCE 600
47 #include "config/have_valgrind.hh"
50 * This class represents a fiber, which is a light weight sort of thread which
51 * is cooperatively scheduled and runs sequentially with other fibers, swapping
52 * in and out of a single actual thread of execution.
54 * To define your own threads, create a subclass of Fiber and override its
55 * main() function to do what you want your fiber to do. You can start it by
56 * calling its run() method which will stop your execution and start the other
57 * fiber in your place.
59 * If your main() function ends, that fiber will automatically switch to either
60 * the primary fiber, or to a particular fiber you specified at construction
61 * time, and your fiber is considered finished.
67 const static size_t DefaultStackSize = 0x50000;
69 /// stack_size is the size of the stack available to this fiber.
70 /// link points to another fiber which will start executing when this
71 /// fiber's main function returns.
72 Fiber(size_t stack_size=DefaultStackSize);
73 Fiber(Fiber *link, size_t stack_size=DefaultStackSize);
77 /// Start executing the fiber represented by this object. This function
78 /// will "return" when the current fiber is switched back to later on.
81 /// Returns whether the "main" function of this fiber has finished.
83 bool finished() const { return _finished; };
85 /// Returns whether the "main" function of this fiber has started.
87 bool started() const { return _started; };
89 /// Get a pointer to the current running Fiber.
91 static Fiber *currentFiber();
92 /// Get a pointer to the primary Fiber.
93 /// This Fiber represents the thread of execution started by the OS, and
94 /// which has a Fiber attached to it after the fact.
95 static Fiber *primaryFiber();
98 /// This method is called when this fiber is first run. Override it to
99 /// give your fiber something to do. When main returns, the fiber will
100 /// mark itself as finished and switch to its link fiber.
101 virtual void main() = 0;
103 void setStarted() { _started = true; }
106 static void entryTrampoline();
112 // The stack for this context, or a nullptr if allocated elsewhere.
116 size_t guardPageSize;
118 unsigned valgrindStackId;
123 void createContext();
126 #endif // __BASE_FIBER_HH__