TransferListenerBase holds its DataTypeDescriptor, which is needed for the upcoming dispatcher class

libuavcan/include/uavcan/internal/transport/transfer_listener.hpp

@@ -87,13 +87,15 @@ public:
  */
 class TransferListenerBase : public LinkedListNode<TransferListenerBase>
 {
-    const Crc16 crc_base_;     ///< Pre-initialized with data type hash, thus constant
+    const DataTypeDescriptor* const data_type_;
+    const Crc16 crc_base_;                      ///< Pre-initialized with data type hash, thus constant
 
     bool checkPayloadCrc(const uint16_t compare_with, const TransferBufferBase& tbb) const;
 
 protected:
     TransferListenerBase(const DataTypeDescriptor* data_type)
-    : crc_base_(data_type->hash.value, DataTypeHash::NUM_BYTES)
+    : data_type_(data_type)
+    , crc_base_(data_type->hash.value, DataTypeHash::NUM_BYTES)
     {
         assert(data_type);
     }
@@ -105,6 +107,8 @@ protected:
     virtual void handleIncomingTransfer(IncomingTransfer& transfer) = 0;
 
 public:
+    const DataTypeDescriptor* getDataTypeDescriptor() const { return data_type_; }
+
     virtual void handleFrame(const RxFrame& frame) = 0;
     virtual void cleanup(uint64_t ts_monotonic) = 0;
 };

libuavcan/test/transport/transfer_listener.cpp

@@ -241,6 +241,11 @@ TEST(TransferListener, TestingEnvironmentSFTSerialization)
 }
 
 
+/**
+ * This subscriber accepts any types of transfers - this makes testing easier.
+ * In reality, uavcan::TransferListener should accept only specific transfer types
+ * which are dispatched/filtered by uavcan::Dispatcher.
+ */
 template <unsigned int MAX_BUF_SIZE, unsigned int NUM_STATIC_BUFS, unsigned int NUM_STATIC_RECEIVERS>
 class TestSubscriber : public uavcan::TransferListener<MAX_BUF_SIZE, NUM_STATIC_BUFS, NUM_STATIC_RECEIVERS>
 {