[PROTON-1241] proton::messaging_handler is not copyable (because it contains a pn_unique_ptr)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: proton-0.14.0
• Component/s: cpp-binding
• Assignee: Andrew Stitcher
• Reporter: Andrew Stitcher
• Created: 20/Jun/16 21:24
• Updated: 01/Sep/16 10:05
• Resolved: 29/Jul/16 22:40

Description

One fundamental of the Proton C++ API is that the user supplies their own handler class.

We should strive in our implementation to limit the API user as little as possible. Unfortunately , because of some historical implementation decisions the messaging_handler class contains a single member which is not copyable (this is a unique_ptr to the associated internal messaging_adapter).

This stops the user being able to natural things with her own classes like:

class MyHandler: public messaging_handler {
...
}
...
auto h = MyHandler{};
...
Myhandler g;
auto i = g;

The user knows what she wants to do with her classes and there is no real intrinsic requirement for the messaging_handler to keep hold of a messaging_adapter. So we need to get out of the users way and remove the pn_unique_ptr from messaging_handler.