From 8891015321fae6aca4218e101109685837a9d2aa Mon Sep 17 00:00:00 2001
From: Pavel Kirienko <pavel.kirienko@gmail.com>
Date: Mon, 8 Jun 2015 11:57:05 +0300
Subject: [PATCH] IRxFrameListener

---
 .../include/uavcan/transport/dispatcher.hpp   | 26 +++++++++++++++++++
 libuavcan/src/transport/uc_dispatcher.cpp     | 10 +++++++
 2 files changed, 36 insertions(+)

diff --git a/libuavcan/include/uavcan/transport/dispatcher.hpp b/libuavcan/include/uavcan/transport/dispatcher.hpp
index 9a277e4f2a..bf615a1665 100644
--- a/libuavcan/include/uavcan/transport/dispatcher.hpp
+++ b/libuavcan/include/uavcan/transport/dispatcher.hpp
@@ -58,6 +58,20 @@ public:
     void invokeListeners(RxFrame& frame);
 };
 
+/**
+ * Implement this interface to receive notifications about all incoming CAN frames, including loopback.
+ */
+class UAVCAN_EXPORT IRxFrameListener
+{
+public:
+    virtual ~IRxFrameListener() { }
+
+    /**
+     * Make sure to filter out loopback frames if they are not wanted.
+     */
+    virtual void handleRxFrame(const CanRxFrame& frame, CanIOFlags flags) = 0;
+};
+
 /**
  * This class performs low-level CAN frame routing.
  */
@@ -103,6 +117,7 @@ class UAVCAN_EXPORT Dispatcher : Noncopyable
     ListenerRegistry lsrv_resp_;
 
     LoopbackFrameListenerRegistry loopback_listeners_;
+    IRxFrameListener* rx_listener_;
 
     NodeID self_node_id_;
     bool self_node_id_is_set_;
@@ -110,11 +125,14 @@ class UAVCAN_EXPORT Dispatcher : Noncopyable
     void handleFrame(const CanRxFrame& can_frame);
     void handleLoopbackFrame(const CanRxFrame& can_frame);
 
+    void notifyRxFrameListener(const CanRxFrame& can_frame, CanIOFlags flags);
+
 public:
     Dispatcher(ICanDriver& driver, IPoolAllocator& allocator, ISystemClock& sysclock, IOutgoingTransferRegistry& otr)
         : canio_(driver, allocator, sysclock)
         , sysclock_(sysclock)
         , outgoing_transfer_reg_(otr)
+        , rx_listener_(NULL)
         , self_node_id_(NodeID::Broadcast)  // Default
         , self_node_id_is_set_(false)
     { }
@@ -180,6 +198,14 @@ public:
 
     LoopbackFrameListenerRegistry& getLoopbackFrameListenerRegistry() { return loopback_listeners_; }
 
+    IRxFrameListener* getRxFrameListener() const { return rx_listener_; }
+    void removeRxFrameListener() { rx_listener_ = NULL; }
+    void installRxFrameListener(IRxFrameListener* listener)
+    {
+        UAVCAN_ASSERT(listener != NULL);
+        rx_listener_ = listener;
+    }
+
     /**
      * Node ID can be set only once.
      * Non-unicast Node ID puts the node into passive mode.
diff --git a/libuavcan/src/transport/uc_dispatcher.cpp b/libuavcan/src/transport/uc_dispatcher.cpp
index eb41b83e52..1c124256fd 100644
--- a/libuavcan/src/transport/uc_dispatcher.cpp
+++ b/libuavcan/src/transport/uc_dispatcher.cpp
@@ -199,6 +199,14 @@ void Dispatcher::handleLoopbackFrame(const CanRxFrame& can_frame)
     loopback_listeners_.invokeListeners(frame);
 }
 
+void Dispatcher::notifyRxFrameListener(const CanRxFrame& can_frame, CanIOFlags flags)
+{
+    if (rx_listener_ != NULL)
+    {
+        rx_listener_->handleRxFrame(can_frame, flags);
+    }
+}
+
 int Dispatcher::spin(MonotonicTime deadline)
 {
     int num_frames_processed = 0;
@@ -222,6 +230,7 @@ int Dispatcher::spin(MonotonicTime deadline)
                 num_frames_processed++;
                 handleFrame(frame);
             }
+            notifyRxFrameListener(frame, flags);
         }
     }
     while (sysclock_.getMonotonic() < deadline);
@@ -253,6 +262,7 @@ int Dispatcher::spinOnce()
                 num_frames_processed++;
                 handleFrame(frame);
             }
+            notifyRxFrameListener(frame, flags);
         }
         else
         {