Async: add sh_ptr<ContinuationChainLink> to Callback<>

This change enables us to finally implement the tracing of
continuations backward from the point of acquisition for deadlock
debugging.

include/asynchronousContinuation.h

@@ -6,6 +6,8 @@
 #include <exception>
 #include <componentThread.h>
 #include <lockSet.h>
+#include <callback.h>
+#include <asynchronousContinuationChainLink.h>
 
 
 namespace smo {
@@ -21,10 +23,11 @@ namespace smo {
  */
 template <class OriginalCbFnT>
 class AsynchronousContinuation
+:	public AsynchronousContinuationChainLink
 {
 public:
-	explicit AsynchronousContinuation(OriginalCbFnT originalCbFn)
-	: originalCbFn(std::move(originalCbFn))
+	explicit AsynchronousContinuation(Callback<OriginalCbFnT> originalCb)
+	: originalCallback(std::move(originalCb))
 	{}
 
 	/**		EXPLANATION:
@@ -65,7 +68,7 @@ public:
 	}
 
 public:
-	OriginalCbFnT originalCbFn;
+	Callback<OriginalCbFnT> originalCallback;
 	std::exception_ptr exception;
 };
 
@@ -84,8 +87,9 @@ class NonPostedAsynchronousContinuation
 :	public AsynchronousContinuation<OriginalCbFnT>
 {
 public:
-	explicit NonPostedAsynchronousContinuation(OriginalCbFnT originalCbFn)
-	:	AsynchronousContinuation<OriginalCbFnT>(originalCbFn)
+	explicit NonPostedAsynchronousContinuation(
+		Callback<OriginalCbFnT> originalCb)
+	:	AsynchronousContinuation<OriginalCbFnT>(originalCb)
 	{}
 
 	/**
@@ -100,10 +104,11 @@ public:
 	template<typename... Args>
 	void callOriginalCb(Args&&... args)
 	{
-		if (AsynchronousContinuation<OriginalCbFnT>::originalCbFn)
+		if (AsynchronousContinuation<OriginalCbFnT>::originalCallback
+			.callbackFn)
 		{
-			AsynchronousContinuation<OriginalCbFnT>::originalCbFn(
-				std::forward<Args>(args)...);
+			AsynchronousContinuation<OriginalCbFnT>::originalCallback
+				.callbackFn(std::forward<Args>(args)...);
 		}
 	}
 };
@@ -115,7 +120,7 @@ class PostedAsynchronousContinuation
 public:
 	PostedAsynchronousContinuation(
 		const std::shared_ptr<ComponentThread> &caller,
-		OriginalCbFnT originalCbFn)
+		Callback<OriginalCbFnT> originalCbFn)
 	:	AsynchronousContinuation<OriginalCbFnT>(originalCbFn),
 	caller(caller)
 	{}
@@ -123,11 +128,13 @@ public:
 	template<typename... Args>
 	void callOriginalCb(Args&&... args)
 	{
-		if (AsynchronousContinuation<OriginalCbFnT>::originalCbFn)
+		if (AsynchronousContinuation<OriginalCbFnT>::originalCallback
+			.callbackFn)
 		{
 			caller->getIoService().post(
 				std::bind(
-					AsynchronousContinuation<OriginalCbFnT>::originalCbFn,
+					AsynchronousContinuation<OriginalCbFnT>::originalCallback
+						.callbackFn,
 					std::forward<Args>(args)...));
 		}
 	}