Add new entry in Release_Notes.

[simgrid.git] / src / kernel / activity / SemaphoreImpl.hpp

diff --git a/src/kernel/activity/SemaphoreImpl.hpp b/src/kernel/activity/SemaphoreImpl.hpp
index e6dc57d..e7b21d2 100644 (file)
--- a/src/kernel/activity/SemaphoreImpl.hpp
+++ b/src/kernel/activity/SemaphoreImpl.hpp
@@ -1,39 +1,71 @@
-/* Copyright (c) 2019. The SimGrid Team. All rights reserved.          */
+/* Copyright (c) 2019-2023. 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. */
 
-#ifndef SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP_
-#define SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP_
+#ifndef SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP
+#define SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP
+
+#include "simgrid/s4u/Semaphore.hpp"
+#include "src/kernel/actor/ActorImpl.hpp"
+#include "src/kernel/actor/SynchroObserver.hpp"
 
 #include <atomic>
 #include <boost/intrusive/list.hpp>
 
-#include "simgrid/s4u/Semaphore.hpp"
-#include "src/kernel/actor/ActorImpl.hpp"
+namespace simgrid::kernel::activity {
+
+/** Semaphore Acquisition: the act / process of acquiring the semaphore.
+ *
+ * You can declare some interest on a semaphore without being blocked waiting if it's already empty.
+ * See the documentation of the MutexAcquisitionImpl for further details.
+ */
+class XBT_PUBLIC SemAcquisitionImpl : public ActivityImpl_T<SemAcquisitionImpl> {
+  actor::ActorImpl* issuer_ = nullptr;
+  SemaphoreImpl* semaphore_ = nullptr;
+  bool granted_             = false;
+
+  friend SemaphoreImpl;
+  friend actor::SemaphoreAcquisitionObserver;
 
-namespace simgrid {
-namespace kernel {
-namespace activity {
+public:
+  SemAcquisitionImpl(actor::ActorImpl* issuer, SemaphoreImpl* sem) : issuer_(issuer), semaphore_(sem) {}
+  SemaphoreImplPtr get_semaphore() { return semaphore_; }
+  actor::ActorImpl* get_issuer() { return issuer_; }
+
+  bool test(actor::ActorImpl* issuer = nullptr) override { return granted_; }
+  void wait_for(actor::ActorImpl* issuer, double timeout) override;
+  void finish() override;
+  void cancel() override;
+  void set_exception(actor::ActorImpl* issuer) override
+  { /* nothing to do */
+  }
+};
 
 class XBT_PUBLIC SemaphoreImpl {
   std::atomic_int_fast32_t refcount_{1};
+  s4u::Semaphore piface_;
   unsigned int value_;
+  std::deque<SemAcquisitionImplPtr> ongoing_acquisitions_;
 
-public:
-  actor::SynchroList sleeping_; /* list of sleeping actors*/
+  static unsigned next_id_;
+  const unsigned id_ = next_id_++;
+
+  friend SemAcquisitionImpl;
+  friend actor::SemaphoreObserver;
 
-  explicit SemaphoreImpl(unsigned int value) : value_(value){};
-  ~SemaphoreImpl() = default;
+public:
+  explicit SemaphoreImpl(unsigned int value) : piface_(this), value_(value){};
 
   SemaphoreImpl(SemaphoreImpl const&) = delete;
   SemaphoreImpl& operator=(SemaphoreImpl const&) = delete;
 
-  void acquire(actor::ActorImpl* issuer, double timeout);
+  SemAcquisitionImplPtr acquire_async(actor::ActorImpl* issuer);
   void release();
-  bool would_block() { return (value_ == 0); }
+  bool would_block() const { return (value_ == 0); }
 
-  unsigned int get_capacity() { return value_; }
+  unsigned int get_capacity() const { return value_; }
+  bool is_used() const { return not ongoing_acquisitions_.empty(); }
 
   friend void intrusive_ptr_add_ref(SemaphoreImpl* sem)
   {
@@ -42,12 +74,14 @@ public:
   }
   friend void intrusive_ptr_release(SemaphoreImpl* sem)
   {
-    if (sem->refcount_.fetch_sub(1) == 1)
+    if (sem->refcount_.fetch_sub(1) == 1) {
+      xbt_assert(not sem->is_used(), "Cannot destroy semaphore since someone is still using it");
       delete sem;
+    }
   }
+  unsigned get_id() const { return id_; }
+  s4u::Semaphore& sem() { return piface_; }
 };
-} // namespace activity
-} // namespace kernel
-} // namespace simgrid
+} // namespace simgrid::kernel::activity
 
-#endif /* SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP_ */
+#endif /* SIMGRID_KERNEL_ACTIVITY_SEMAPHOREIMPL_HPP */