+/** @brief returns if there this transition can proceed in a finite amount of time
+ *
+ * It is used in the model-checker to not get into self-deadlock where it would execute a never ending transition.
+ *
+ * Only WAIT operations (on comm, on mutex, etc) can ever return false because they could lock the MC exploration.
+ * Wait operations are OK and return true in only two situations:
+ * - if the wait will succeed immediately (if both peer of the comm are there already or if the mutex is available)
+ * - if a timeout is provided, because we can fire the timeout if the transition is not ready without blocking in this
+ * transition for ever.
+ *
+ */
+// Called from both MCer and MCed:
+bool actor_is_enabled(smx_actor_t actor)
+{
+ smx_simcall_t req = &actor->simcall;
+ // TODO, add support for the subtypes?
+
+ switch (req->call) {
+ case SIMCALL_NONE:
+ return false;
+
+ case SIMCALL_COMM_WAIT: {
+ /* FIXME: check also that src and dst processes are not suspended */
+ simgrid::kernel::activity::CommImpl* act =
+ static_cast<simgrid::kernel::activity::CommImpl*>(simcall_comm_wait__getraw__comm(req));
+
+#if SIMGRID_HAVE_MC
+ // Fetch from MCed memory:
+ // HACK, type puning
+ if (mc_model_checker != nullptr) {
+ simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
+ mc_model_checker->process().read(temp_comm, remote(act));
+ act = static_cast<simgrid::kernel::activity::CommImpl*>(temp_comm.getBuffer());
+ }
+#endif
+
+ if (act->src_timeout || act->dst_timeout) {
+ /* If it has a timeout it will be always be enabled (regardless of who declared the timeout),
+ * because even if the communication is not ready, it can timeout and won't block. */
+ if (_sg_mc_timeout == 1)
+ return true;
+ }
+ /* On the other hand if it hasn't a timeout, check if the comm is ready.*/
+ else if (act->detached && act->src_proc == nullptr && act->type == SIMIX_COMM_READY)
+ return (act->dst_proc != nullptr);
+ return (act->src_proc && act->dst_proc);
+ }
+
+ case SIMCALL_COMM_WAITANY: {
+ xbt_dynar_t comms;
+ simgrid::kernel::activity::CommImpl* act =
+ static_cast<simgrid::kernel::activity::CommImpl*>(simcall_comm_wait__getraw__comm(req));
+
+#if SIMGRID_HAVE_MC
+ s_xbt_dynar_t comms_buffer;
+ size_t buffer_size = 0;
+ if (mc_model_checker != nullptr) {
+ // Read dynar:
+ mc_model_checker->process().read(&comms_buffer, remote(simcall_comm_waitany__get__comms(req)));
+ assert(comms_buffer.elmsize == sizeof(act));
+ buffer_size = comms_buffer.elmsize * comms_buffer.used;
+ comms = &comms_buffer;
+ } else
+ comms = simcall_comm_waitany__get__comms(req);
+
+ // Read all the dynar buffer:
+ char buffer[buffer_size];
+ if (mc_model_checker != nullptr)
+ mc_model_checker->process().read_bytes(buffer, sizeof(buffer), remote(comms->data));
+#else
+ comms = simcall_comm_waitany__get__comms(req);
+#endif
+
+ for (unsigned int index = 0; index < comms->used; ++index) {
+#if SIMGRID_HAVE_MC
+ // Fetch act from MCed memory:
+ // HACK, type puning
+ simgrid::mc::Remote<simgrid::kernel::activity::CommImpl> temp_comm;
+ if (mc_model_checker != nullptr) {
+ memcpy(&act, buffer + comms->elmsize * index, sizeof(act));
+ mc_model_checker->process().read(temp_comm, remote(act));
+ act = static_cast<simgrid::kernel::activity::CommImpl*>(temp_comm.getBuffer());
+ } else
+#endif
+ act = xbt_dynar_get_as(comms, index, simgrid::kernel::activity::CommImpl*);
+ if (act->src_proc && act->dst_proc)
+ return true;
+ }
+ return false;
+ }
+
+ case SIMCALL_MUTEX_LOCK: {
+ smx_mutex_t mutex = simcall_mutex_lock__get__mutex(req);
+#if SIMGRID_HAVE_MC
+ simgrid::mc::Remote<simgrid::simix::MutexImpl> temp_mutex;
+ if (mc_model_checker != nullptr) {
+ mc_model_checker->process().read(temp_mutex.getBuffer(), remote(mutex));
+ mutex = temp_mutex.getBuffer();
+ }
+#endif
+
+ if (mutex->owner == nullptr)
+ return true;
+#if SIMGRID_HAVE_MC
+ else if (mc_model_checker != nullptr) {
+ simgrid::mc::RemoteClient& modelchecked = mc_model_checker->process();
+ // TODO, *(mutex->owner) :/
+ return modelchecked.resolveActor(simgrid::mc::remote(mutex->owner))->pid ==
+ modelchecked.resolveActor(simgrid::mc::remote(req->issuer))->pid;
+ }
+#endif
+ else
+ return mutex->owner->pid == req->issuer->pid;
+ }
+
+ case SIMCALL_SEM_ACQUIRE: {
+ static int warned = 0;
+ if (not warned)
+ XBT_INFO("Using semaphore in model-checked code is still experimental. Use at your own risk");
+ warned = 1;
+ return true;
+ }
+
+ case SIMCALL_COND_WAIT: {
+ static int warned = 0;
+ if (not warned)
+ XBT_INFO("Using condition variables in model-checked code is still experimental. Use at your own risk");
+ warned = 1;
+ return true;
+ }
+
+ default:
+ /* The rest of the requests are always enabled */
+ return true;
+ }
+}
