1 files changed, 74 insertions, 17 deletions

diff --git a/cpp/src/qpid/framing/Handler.h b/cpp/src/qpid/framing/Handler.h
index 2f09911325..be49570f9b 100644
--- a/cpp/src/qpid/framing/Handler.h
+++ b/cpp/src/qpid/framing/Handler.h
@@ -27,33 +27,90 @@
 namespace qpid {
 namespace framing {
 
-/** Interface for handler for values of type T.
- * Handlers can be linked into chains via the next pointer.
- */
-template <class T> struct Handler {
-    typedef T ParamType;
-    typedef shared_ptr<Handler> Chain;
+/** Generic handler that can be linked into chains. */
+template <class T>
+struct Handler {
+    typedef T HandledType;
+
+    Handler(Handler<T>* next_=0) : next(next_) {}
+    virtual ~Handler() {}
+    virtual void handle(T) = 0;
+    
+    /** Allow functor syntax for calling handle */ 
+    void operator()(T t)  { handle(t); }
+
 
-    /** Handler chains for incoming and outgoing traffic. */
+    /** Pointer to next handler in a linked list. */
+    Handler<T>* next;
+
+    /** A Chain is a handler that forwards to a modifiable
+     * linked list of handlers.
+     */
+    struct Chain : public Handler<T> {
+        Chain(Handler<T>* first) : Handler(first) {}
+        void operator=(Handler<T>* h) { next = h; }
+        void handle(T t) { (*next)(t); }
+        // TODO aconway 2007-08-29: chain modifier ops here.
+    };
+
+    /** In/out pair of handler chains. */
     struct Chains {
-        Chains() {}
-        Chains(Chain i, Chain o) : in(i), out(o) {}
-        Chains(Handler* i, Handler* o) : in(i), out(o) {}
+        Chains(Handler<T>* in_=0, Handler<T>* out_=0) : in(in_), out(out_) {}
+        void reset(Handler<T>* in_=0, Handler<T>* out_=0) { in = in_; out = out_; }
         Chain in;
         Chain out;
     };
 
-    Handler() {}
-    Handler(Chain next_) : next(next_) {}
-    virtual ~Handler() {}
+    /** Adapt any void(T) functor as a Handler.
+     * Functor<F>(f) will copy f.
+     * Functor<F&>(f) will only take a reference to x.
+     */
+    template <class F> class Functor : public Handler<T> {
+      public:
+        Functor(F f, Handler<T>* next=0) : Handler<T>(next), functor(f) {}
+        void handle(T t) { functor(t); }
+      private:
+        F functor;
+    };
 
-    virtual void handle(T) = 0;
+    /** Adapt a member function of X as a Handler.
+     * MemFun<X, X::f> will copy x.
+     * MemFun<X&, X::f> will only take a reference to x.
+     */
+    template <class X, void(*M)(T)>
+    class MemFun : public Handler<T> {
+      public:
+        MemFun(X x, Handler<T>* next=0) : Handler(next), object(x) {}
+        void handle(T t) { object.*M(t); }
+      private:
+        X object;
+    };
+
+    /** Support for implementing an in-out handler pair as a single class.
+     * Public interface is Handler<T>::Chains pair, but implementation
+     * overrides handleIn, handleOut functions in a single class.
+     */
+    class InOutHandler {
+      public:
+        virtual ~InOutHandler() {}
+
+        InOutHandler() :
+            in(*this, &InOutHandler::handleIn),
+            out(*this, &InOutHandler::handleOut) {}
+
+        MemFun<InOutHandler, &InOutHandler::handleIn> in;
+        MemFun<InOutHandler, &InOutHandler::handleOut> out;
+
+      protected:
+        virtual void handleIn(T) = 0;
+        virtual void handleOut(T) = 0;
+      private:
+    };
 
-    /** Next handler. Public so chains can be modified by altering next. */
-    Chain next;
 };
 
-}}
 
 
+}}
 #endif  /*!QPID_FRAMING_HANDLER_H*/
+//