1 /* Copyright (c) 2019-2022. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #ifndef SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP
7 #define SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP
10 #include <boost/intrusive/list.hpp>
12 #include "simgrid/s4u/Semaphore.hpp"
13 #include "src/kernel/actor/ActorImpl.hpp"
19 class XBT_PUBLIC SemaphoreImpl {
20 std::atomic_int_fast32_t refcount_{1};
21 s4u::Semaphore piface_;
23 actor::SynchroList sleeping_; /* list of sleeping actors*/
26 explicit SemaphoreImpl(unsigned int value) : piface_(this), value_(value){};
28 SemaphoreImpl(SemaphoreImpl const&) = delete;
29 SemaphoreImpl& operator=(SemaphoreImpl const&) = delete;
31 void acquire(actor::ActorImpl* issuer, double timeout);
33 bool would_block() const { return (value_ == 0); }
34 void remove_sleeping_actor(actor::ActorImpl& actor) { xbt::intrusive_erase(sleeping_, actor); }
36 unsigned int get_capacity() const { return value_; }
37 bool is_used() const { return not sleeping_.empty(); }
42 friend void intrusive_ptr_add_ref(SemaphoreImpl* sem)
44 XBT_ATTRIB_UNUSED auto previous = sem->refcount_.fetch_add(1);
45 xbt_assert(previous != 0);
47 friend void intrusive_ptr_release(SemaphoreImpl* sem)
49 if (sem->refcount_.fetch_sub(1) == 1) {
50 xbt_assert(not sem->is_used(), "Cannot destroy semaphore since someone is still using it");
55 s4u::Semaphore& sem() { return piface_; }
57 } // namespace activity
59 } // namespace simgrid
61 #endif /* SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP */