Add SemaphoreImpl::piface_ (mimic MutexImpl).

Also make constructor private to enforce usage of create(), and fix bogus destructor.

Like for Mutex, could not manage to make ~Semaphore() private.

diff --git a/include/simgrid/forward.h b/include/simgrid/forward.h
index 72889a3..1eef471 100644 (file)
--- a/include/simgrid/forward.h
+++ b/include/simgrid/forward.h
@@ -86,8 +86,8 @@ class File;
 class Semaphore;
 /** Smart pointer to a simgrid::s4u::Semaphore */
 using SemaphorePtr = boost::intrusive_ptr<Semaphore>;
-XBT_PUBLIC void intrusive_ptr_release(Semaphore* m);
-XBT_PUBLIC void intrusive_ptr_add_ref(Semaphore* m);
+XBT_PUBLIC void intrusive_ptr_release(const Semaphore* m);
+XBT_PUBLIC void intrusive_ptr_add_ref(const Semaphore* m);
 
 class Disk;
 } // namespace s4u

diff --git a/include/simgrid/s4u/Semaphore.hpp b/include/simgrid/s4u/Semaphore.hpp
index 6c93a8b..b100ba5 100644 (file)
--- a/include/simgrid/s4u/Semaphore.hpp
+++ b/include/simgrid/s4u/Semaphore.hpp
@@ -29,21 +29,20 @@ namespace s4u {
  *
  */
 class XBT_PUBLIC Semaphore {
-  kernel::activity::SemaphoreImpl* const pimpl_;
-  std::atomic_int_fast32_t refcount_{0};
+  friend kernel::activity::SemaphoreImpl;
 
-  friend void intrusive_ptr_add_ref(Semaphore* sem);
-  friend void intrusive_ptr_release(Semaphore* sem);
+  kernel::activity::SemaphoreImpl* const pimpl_;
 
-public:
-  explicit Semaphore(unsigned int initial_capacity);
-  ~Semaphore();
+  friend void intrusive_ptr_add_ref(const Semaphore* sem);
+  friend void intrusive_ptr_release(const Semaphore* sem);
 
+  explicit Semaphore(kernel::activity::SemaphoreImpl* sem) : pimpl_(sem) {}
 #ifndef DOXYGEN
   Semaphore(Semaphore const&) = delete;            // No copy constructor. Use SemaphorePtr instead
   Semaphore& operator=(Semaphore const&) = delete; // No direct assignment either. Use SemaphorePtr instead
 #endif
 
+public:
   /** Constructs a new semaphore */
   static SemaphorePtr create(unsigned int initial_capacity);
 

diff --git a/src/kernel/activity/SemaphoreImpl.cpp b/src/kernel/activity/SemaphoreImpl.cpp
index 98d38be..fbfffa1 100644 (file)
--- a/src/kernel/activity/SemaphoreImpl.cpp
+++ b/src/kernel/activity/SemaphoreImpl.cpp
@@ -43,6 +43,19 @@ void SemaphoreImpl::release()
   }
 }
 
+/** Increase the refcount for this semaphore */
+SemaphoreImpl* SemaphoreImpl::ref()
+{
+  intrusive_ptr_add_ref(this);
+  return this;
+}
+
+/** Decrease the refcount for this mutex */
+void SemaphoreImpl::unref()
+{
+  intrusive_ptr_release(this);
+}
+
 } // namespace activity
 } // namespace kernel
 } // namespace simgrid

diff --git a/src/kernel/activity/SemaphoreImpl.hpp b/src/kernel/activity/SemaphoreImpl.hpp
index 3be684e..33793ce 100644 (file)
--- a/src/kernel/activity/SemaphoreImpl.hpp
+++ b/src/kernel/activity/SemaphoreImpl.hpp
@@ -18,11 +18,12 @@ namespace activity {
 
 class XBT_PUBLIC SemaphoreImpl {
   std::atomic_int_fast32_t refcount_{1};
+  s4u::Semaphore piface_;
   unsigned int value_;
   actor::SynchroList sleeping_; /* list of sleeping actors*/
 
 public:
-  explicit SemaphoreImpl(unsigned int value) : value_(value){};
+  explicit SemaphoreImpl(unsigned int value) : piface_(this), value_(value){};
 
   SemaphoreImpl(SemaphoreImpl const&) = delete;
   SemaphoreImpl& operator=(SemaphoreImpl const&) = delete;
@@ -35,6 +36,9 @@ public:
   unsigned int get_capacity() const { return value_; }
   bool is_used() const { return not sleeping_.empty(); }
 
+  SemaphoreImpl* ref();
+  void unref();
+
   friend void intrusive_ptr_add_ref(SemaphoreImpl* sem)
   {
     XBT_ATTRIB_UNUSED auto previous = sem->refcount_.fetch_add(1);
@@ -42,9 +46,13 @@ 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;
+    }
   }
+
+  s4u::Semaphore& sem() { return piface_; }
 };
 } // namespace activity
 } // namespace kernel

diff --git a/src/s4u/s4u_Semaphore.cpp b/src/s4u/s4u_Semaphore.cpp
index 7e3a567..b2482ed 100644 (file)
--- a/src/s4u/s4u_Semaphore.cpp
+++ b/src/s4u/s4u_Semaphore.cpp
@@ -13,17 +13,10 @@
 namespace simgrid {
 namespace s4u {
 
-Semaphore::Semaphore(unsigned int initial_capacity) : pimpl_(new kernel::activity::SemaphoreImpl(initial_capacity)) {}
-
-Semaphore::~Semaphore()
-{
-  xbt_assert(not pimpl_->is_used(), "Cannot destroy semaphore since someone is still using it");
-  delete pimpl_;
-}
-
 SemaphorePtr Semaphore::create(unsigned int initial_capacity)
 {
-  return SemaphorePtr(new Semaphore(initial_capacity));
+  auto* sem = new kernel::activity::SemaphoreImpl(initial_capacity);
+  return SemaphorePtr(&sem->sem(), false);
 }
 
 void Semaphore::acquire()
@@ -51,19 +44,17 @@ bool Semaphore::would_block() const
   return kernel::actor::simcall([this] { return pimpl_->would_block(); });
 }
 
-void intrusive_ptr_add_ref(Semaphore* sem)
+/* refcounting of the intrusive_ptr is delegated to the implementation object */
+void intrusive_ptr_add_ref(const Semaphore* sem)
 {
   xbt_assert(sem);
-  sem->refcount_.fetch_add(1, std::memory_order_relaxed);
+  sem->pimpl_->ref();
 }
 
-void intrusive_ptr_release(Semaphore* sem)
+void intrusive_ptr_release(const Semaphore* sem)
 {
   xbt_assert(sem);
-  if (sem->refcount_.fetch_sub(1, std::memory_order_release) == 1) {
-    std::atomic_thread_fence(std::memory_order_acquire);
-    delete sem;
-  }
+  sem->pimpl_->unref();
 }
 
 } // namespace s4u
@@ -73,7 +64,7 @@ void intrusive_ptr_release(Semaphore* sem)
 /** @brief creates a semaphore object of the given initial capacity */
 sg_sem_t sg_sem_init(int initial_value)
 {
-  return new simgrid::s4u::Semaphore(initial_value);
+  return simgrid::s4u::Semaphore::create(initial_value).detach();
 }
 
 /** @brief locks on a semaphore object */
@@ -101,7 +92,7 @@ int sg_sem_get_capacity(const_sg_sem_t sem)
 
 void sg_sem_destroy(const_sg_sem_t sem)
 {
-  delete sem;
+  intrusive_ptr_release(sem);
 }
 
 /** @brief returns a boolean indicating if this semaphore would block at this very specific time