Fix a doc error about actors (Tutorial_algorithms)

[simgrid.git] / src / s4u / s4u_Barrier.cpp

diff --git a/src/s4u/s4u_Barrier.cpp b/src/s4u/s4u_Barrier.cpp
index 482a164..be8bb6e 100644 (file)
--- a/src/s4u/s4u_Barrier.cpp
+++ b/src/s4u/s4u_Barrier.cpp
@@ -1,4 +1,4 @@
-/* Copyright (c) 2018. The SimGrid Team. All rights reserved.          */
+/* Copyright (c) 2018-2019. The SimGrid Team. All rights reserved.          */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
@@ -6,41 +6,86 @@
 #include <exception>
 #include <mutex>
 
-#include <xbt/ex.hpp>
-#include <xbt/log.hpp>
-
+#include "simgrid/Exception.hpp"
+#include "simgrid/barrier.h"
 #include "simgrid/s4u/Barrier.hpp"
 #include "simgrid/simix.h"
+#include "xbt/log.hpp"
 
 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_barrier, "S4U barrier");
 
 namespace simgrid {
 namespace s4u {
 
-Barrier::Barrier(unsigned int count) : expected_processes_(count)
+Barrier::Barrier(unsigned int expected_processes)
+    : mutex_(Mutex::create()), cond_(ConditionVariable::create()), expected_actors_(expected_processes)
+{
+}
+
+/** @brief Create a new barrier
+ *
+ * See @ref s4u_raii.
+ */
+BarrierPtr Barrier::create(unsigned int expected_actors)
 {
-  mutex_ = Mutex::create();
-  cond_  = ConditionVariable::create();
+  return BarrierPtr(new Barrier(expected_actors));
 }
 
-/**
- * Wait functions
+/** @brief Block the current actor until all expected actors reach the barrier.
+ *
+ * This method is meant to be somewhat consistent with the pthread_barrier_wait function.
+ *
+ * @return 0 for all actors but one: exactly one actor will get SG_BARRIER_SERIAL_THREAD as a return value.
  */
 int Barrier::wait()
 {
   mutex_->lock();
-  arrived_processes_++;
-  XBT_DEBUG("waiting %p %u/%u", this, arrived_processes_, expected_processes_);
-  if (arrived_processes_ == expected_processes_) {
+  arrived_actors_++;
+  XBT_DEBUG("waiting %p %u/%u", this, arrived_actors_, expected_actors_);
+  if (arrived_actors_ == expected_actors_) {
     cond_->notify_all();
     mutex_->unlock();
-    arrived_processes_ = 0;
-    return -1;
+    arrived_actors_ = 0;
+    return SG_BARRIER_SERIAL_THREAD;
   }
 
   cond_->wait(mutex_);
   mutex_->unlock();
   return 0;
 }
+
+void intrusive_ptr_add_ref(Barrier* barrier)
+{
+  xbt_assert(barrier);
+  barrier->refcount_.fetch_add(1, std::memory_order_relaxed);
+}
+
+void intrusive_ptr_release(Barrier* barrier)
+{
+  xbt_assert(barrier);
+  if (barrier->refcount_.fetch_sub(1, std::memory_order_release) == 1) {
+    std::atomic_thread_fence(std::memory_order_acquire);
+    delete barrier;
+  }
+}
 } // namespace s4u
 } // namespace simgrid
+
+/* **************************** Public C interface *************************** */
+
+sg_bar_t sg_barrier_init(unsigned int count)
+{
+  return new simgrid::s4u::Barrier(count);
+}
+
+/** @brief Initializes a barrier, with count elements */
+void sg_barrier_destroy(sg_bar_t bar)
+{
+  delete bar;
+}
+
+/** @brief Performs a barrier already initialized */
+int sg_barrier_wait(sg_bar_t bar)
+{
+  return bar->wait();
+}