Signatures of callbacks async_reply_handler, signal_handler, message_handler and property_set_callback were modified to take input message objects by value, as opposed to non-const ref.
The callee assumes ownership of the message. This API is more idiomatic, more expressive, cleaner and safer. Move semantics is used to pass messages to the callback handlers. In some cases, this also improves performance.
* Catch and process all exceptions (not just sdbus::Error) from callback handlers
* Unify handling of exceptions from all types of callbacks -- always set sd_bus_error and return a negative result number in case of exception
Although libsystemd logs (with DEBUG severity) all errors from such callback handlers (except method callback handler), it seems to be out of our control. One of handy sdbus-c++ features could be the ability for clients to install a log callback, which sdbus-c++ would call in case of exceptions flying from callback handlers. In case something doesn't work for clients (especially novices), they can first look into these logs.
This may be handy in common situations like ignored signals on client side because of the inadvertent mismatch between real signal signature and signal handler signature. Like here: #373. (Although in this specific case of signals, there is a solution with an additional const sdbus::Error* argument that would reveal such an error.)
* feat: add async property get/set convenience support classes
* feat: add no-reply and async overloads to Properties_proxy
* feat: add convenience functions for GetAll functionality
* test: add tests for new functionality
* add codegen IDL support and documentation
This change addresses conditions where an exception is thrown by the library upon receipt of a malformed message from an external
source, and propagated up to the event loop with no chance of
interception by the application. This issue is only experienced by
proxy convenience APIs, as low-level APIs allow the application to
unpack the message.
Strategy:
1. For malformed signals received by proxies: ignore the signal.
2. For malformed async method responses, translate the unpack
exception into an sdbus::Error, and pass it to the caller as expected.
Stanislav Angelovič
Stanislav Angelovic
Osama Ghanem
David Leeds
sangelovic
lubo-svk