Use atomics for the reference counting. Fixes #4.

blue42u · Apr 27, 2019 · 09ec532 · 09ec532
1 parent d9e672c
commit 09ec532
Show file tree

Hide file tree

Showing 2 changed files with 18 additions and 5 deletions.
diff --git a/symtabAPI/h/Type.h b/symtabAPI/h/Type.h
@@ -175,7 +175,18 @@ class SYMTAB_EXPORT Type : public Serializable, public  TYPE_ANNOTATABLE_CLASS
     **/
    bool updatingSize;
 
-   unsigned int refCount;
+   // Boost's atomic doesn't support operator =, although std::atomic does.
+   // This wrapper class makes up for the deficiency
+   template<typename T>
+   struct stdatomic : public boost::atomic<T> {
+       stdatomic(const T& v) : boost::atomic<T>(v) {};
+       ~stdatomic() {};
+       stdatomic& operator=(const stdatomic<T>& other) {
+           this->store(other.load());
+           return *this;
+       }
+   };
+   stdatomic<unsigned int> refCount;
 
    static boost::atomic<typeId_t> USER_TYPE_ID;
 

diff --git a/symtabAPI/src/Type.C b/symtabAPI/src/Type.C
@@ -248,13 +248,15 @@ bool Type::setSize(unsigned int size)
 
 void Type::incrRefCount() 
 {
-	++refCount;
+	refCount.fetch_add(1, boost::memory_order_relaxed);
 }
 
 void Type::decrRefCount() 
 {
-    --refCount;
-    if(refCount == 0) delete this;
+    if(refCount.fetch_sub(1, boost::memory_order_relaxed) == 1) {
+        boost::atomic_thread_fence(boost::memory_order_acquire);
+        delete this;
+    }
 }
 
 std::string &Type::getName()
@@ -1921,7 +1923,7 @@ Serializable * Type::serialize_impl(SerializerBase *s, const char *tag) THROW_SP
 	if (s->isInput())
 	{
 		updatingSize = false;
-		refCount = 0;
+                refCount.store(0, boost::memory_order_relaxed);
 
 		// Ensure that unique type id is the next (increasingly negative) type ID available for user defined types.
 		updateUniqueTypeId(ID_);