X-Git-Url: http://bilbo.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/2ca35a707044d033c33cb4f016e6ffddfded0d05..4fb5244980199691e9976323c2c3a09ebb168242:/include/simgrid/s4u/Mutex.hpp

diff --git a/include/simgrid/s4u/Mutex.hpp b/include/simgrid/s4u/Mutex.hpp
index 241ae36f91..29d9ed1043 100644
--- a/include/simgrid/s4u/Mutex.hpp
+++ b/include/simgrid/s4u/Mutex.hpp
@@ -1,4 +1,4 @@
-/* Copyright (c) 2006-2015. The SimGrid Team. All rights reserved.          */
+/* Copyright (c) 2006-2023. 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. */
@@ -6,53 +6,60 @@
 #ifndef SIMGRID_S4U_MUTEX_HPP
 #define SIMGRID_S4U_MUTEX_HPP
 
-#include <mutex>
-#include <utility>
+#include "simgrid/s4u/Actor.hpp"
+#include <simgrid/forward.h>
+#include <xbt/asserts.h>
 
-#include <boost/intrusive_ptr.hpp>
+namespace simgrid::s4u {
 
-#include <xbt/base.h>
-#include "simgrid/simix.h"
+/** @brief A classical mutex, but blocking in the simulation world.
+ *
+ * S4U mutexes are not recursive. If an actor tries to lock the same object twice, it deadlocks with itself.
+ *
+ * @beginrst
+ * It is strictly impossible to use a real mutex, such as
+ * `std::mutex <http://en.cppreference.com/w/cpp/thread/mutex>`_
+ * or `pthread_mutex_t <http://pubs.opengroup.org/onlinepubs/007908775/xsh/pthread_mutex_lock.html>`_,
+ * because it would block the whole simulation.
+ * Instead, you should use the present class, that is a drop-in replacement of these mechanisms.
+ *
+ * An example is available in Section :ref:`s4u_ex_IPC`.
+ *
+ * As for any S4U object, you can use the :ref:`RAII idiom <s4u_raii>` for memory management of Mutexes.
+ * Use :cpp:func:`create() <simgrid::s4u::Mutex::create()>` to get a :cpp:type:`simgrid::s4u::MutexPtr` to a newly
+ * created mutex, and only manipulate :cpp:type:`simgrid::s4u::MutexPtr`.
+ * @endrst
+ */
+class XBT_PUBLIC Mutex {
+#ifndef DOXYGEN
+  friend ConditionVariable;
+  friend kernel::activity::MutexImpl;
+  friend XBT_PUBLIC void kernel::activity::intrusive_ptr_release(kernel::activity::MutexImpl* mutex);
+#endif
 
-namespace simgrid {
-namespace s4u {
+  kernel::activity::MutexImpl* const pimpl_;
+  /* refcounting */
+  friend XBT_PUBLIC void intrusive_ptr_add_ref(const Mutex* mutex);
+  friend XBT_PUBLIC void intrusive_ptr_release(const Mutex* mutex);
 
-class ConditionVariable;
+  explicit Mutex(kernel::activity::MutexImpl* mutex) : pimpl_(mutex) {}
+  ~Mutex() = default;
+#ifndef DOXYGEN
+  Mutex(Mutex const&) = delete;            // No copy constructor; Use MutexPtr instead
+  Mutex& operator=(Mutex const&) = delete; // No direct assignment either. Use MutexPtr instead
+#endif
 
-XBT_PUBLIC_CLASS Mutex {
-friend ConditionVariable;
-private:
-  friend simgrid::simix::Mutex;
-  simgrid::simix::Mutex* mutex_;
-  Mutex(simgrid::simix::Mutex* mutex) : mutex_(mutex) {}
 public:
+  /** \static Constructs a new mutex */
+  static MutexPtr create(bool recursive = false);
 
-  friend void intrusive_ptr_add_ref(Mutex* mutex)
-  {
-    xbt_assert(mutex);
-    SIMIX_mutex_ref(mutex->mutex_);
-  }
-  friend void intrusive_ptr_release(Mutex* mutex)
-  {
-    xbt_assert(mutex);
-    SIMIX_mutex_unref(mutex->mutex_);
-  }
-  using Ptr = boost::intrusive_ptr<Mutex>;
-
-  // No copy:
-  Mutex(Mutex const&) = delete;
-  Mutex& operator=(Mutex const&) = delete;
-
-  static Ptr createMutex();
-
-public:
   void lock();
   void unlock();
   bool try_lock();
-};
 
-using MutexPtr = Mutex::Ptr;
+  Actor* get_owner();
+};
 
-}} // namespace simgrid::s4u
+} // namespace simgrid::s4u
 
 #endif /* SIMGRID_S4U_MUTEX_HPP */