ChannelProvider::createChannel() optional ChannelRequester

src/ca/caChannel.cpp

@@ -284,12 +284,12 @@ void CAChannel::activate(short priority)
         channelProvider->registerChannel(shared_from_this());
 
         // TODO be sure that ca_connection_handler is not called before this call
-        EXCEPTION_GUARD(channelRequester->channelCreated(Status::Ok, shared_from_this()));
+        channelRequester->channelCreated(Status::Ok, shared_from_this());
     }
     else
     {
         Status errorStatus(Status::STATUSTYPE_ERROR, string(ca_message(result)));
-        EXCEPTION_GUARD(channelRequester->channelCreated(errorStatus, shared_from_this()));
+        channelRequester->channelCreated(errorStatus, shared_from_this());
     }
 }
 

src/client/pv/pvAccess.h

@@ -1023,6 +1023,16 @@ public:
     virtual void channelStateChange(Channel::shared_pointer const & channel, Channel::ConnectionState connectionState) = 0;
 };
 
+//! Used when ChannelProvider::createChannel() is passed a NULL ChannelRequester
+struct epicsShareClass DefaultChannelRequester : public ChannelRequester
+{
+    virtual ~DefaultChannelRequester() {}
+    virtual std::string getRequesterName();
+    virtual void channelCreated(const epics::pvData::Status& status, Channel::shared_pointer const & channel);
+    virtual void channelStateChange(Channel::shared_pointer const & channel, Channel::ConnectionState connectionState);
+    static ChannelRequester::shared_pointer build();
+};
+
 /**
  * @brief The FlushStrategy enum
  */
@@ -1087,8 +1097,9 @@ public:
     /**
      * See longer form
      */
-    virtual Channel::shared_pointer createChannel(std::string const & name,ChannelRequester::shared_pointer const & requester,
-            short priority = PRIORITY_DEFAULT);
+    virtual Channel::shared_pointer createChannel(std::string const & name,
+                                                  ChannelRequester::shared_pointer const & requester = DefaultChannelRequester::build(),
+                                                  short priority = PRIORITY_DEFAULT);
 
     /**
      * Request a Channel.

src/client/pvAccess.cpp

@@ -100,5 +100,26 @@ ChannelArray::shared_pointer Channel::createChannelArray(
     return ret;
 }
 
+std::string DefaultChannelRequester::getRequesterName() { return "DefaultChannelRequester"; }
+
+void DefaultChannelRequester::channelCreated(const epics::pvData::Status& status, Channel::shared_pointer const & channel)
+{
+    if(!status.isSuccess()) {
+        std::ostringstream strm;
+        status.dump(strm);
+        throw std::runtime_error(strm.str());
+    }
+}
+
+void DefaultChannelRequester::channelStateChange(Channel::shared_pointer const & channel, Channel::ConnectionState connectionState)
+{ /* no-op */ }
+
+ChannelRequester::shared_pointer DefaultChannelRequester::build()
+{
+    ChannelRequester::shared_pointer ret(new DefaultChannelRequester);
+    return ret;
+}
+
+
 }
 }