sys::RefCountedMap - reference-counted weak map of reference-counted objects.

Ensures objects are atomically deleted and removed from the map.



git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@629263 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 18 insertions, 5 deletions

diff --git a/cpp/src/qpid/RefCounted.h b/cpp/src/qpid/RefCounted.h
index bcef69d21e..c325b204d4 100644
--- a/cpp/src/qpid/RefCounted.h
+++ b/cpp/src/qpid/RefCounted.h
@@ -39,10 +39,9 @@ class AbstractRefCounted {
 };
 
 /**
- * Reference-counted virtual base class.
+ * Reference-counted base class.
  */
-class RefCounted : public AbstractRefCounted
-{
+class RefCounted : public AbstractRefCounted {
   public:
     RefCounted() {}
     virtual void addRef() const { ++count; }
@@ -53,12 +52,26 @@ class RefCounted : public AbstractRefCounted
     // Copy/assign do not copy refcounts. 
     RefCounted(const RefCounted&) : AbstractRefCounted() {}
     RefCounted& operator=(const RefCounted&) { return *this; }
-    virtual void released() const { delete this; }
+    virtual void released() const { assert(count==0); delete this; }
 
-  private:
     mutable sys::AtomicCount count;
 };
 
+/**
+ * Reference-counted member of a reference-counted parent class.
+ * Delegates reference counts to the parent so that the parent is
+ * deleted only when there are no references to the parent or any of
+ * its children.
+ */
+struct RefCountedChild : public AbstractRefCounted {
+  protected:
+    AbstractRefCounted& parent;
+    RefCountedChild(AbstractRefCounted& parent_) : parent(parent_) {}
+  public:
+    void addRef() const { parent.addRef(); }
+    void release() const { parent.release(); }
+};
+
 using boost::intrusive_ptr;
 
 } // namespace qpid