zbus-lockstep-macros

zbus-lockstep-macros extends zbus-lockstep to match the signature of signal types <T as zvariant::Type>::signature() with a corresponding signature from a DBus XML file more conveniently and succinctly.

Motivation

In the context of IPC over DBus, especially where there are multiple implementations of servers and/or clients communicating, it is necessary for each implementation to send what others expect and that expectations are in accordance with what is sent over the bus.

The XML protocol-descriptions may act as a shared frame of reference or "single source of all truth" for all implementers. Having a single point of reference helps all implementers meet expectations on protocol conformance.

Keeping the types you send over DBus in lockstep with currently valid protocol-descriptions will reduce chances of miscommunication or failure to communicate.

Use

Add zbus-lockstep-macros to Cargo.toml's dependencies:

[dependencies]
zbus-lockstep-macros = "0.4.4"

If the DBus XML descriptions can be found in the crates root, in either xml/ or XML/, validating the type can be as easy as:

 use zbus_lockstep_macros::validate;
 use zvariant::Type;

 #[validate]
 #[derive(Type)]
 struct BirthdayEvent {
    name: String,
    new_age: u8,
}

Note that the macro assumes that the member name is contained in the struct name. You can provide the member name if you have another naming-scheme in use.

Also, it may be necessary to disambiguate if multiple interfaces across the DBus descriptions provide signals with the same name.

Any of the arguments are optional.

#[validate(xml: <xml_path>, interface: <interface_name>, member: <member_name>)]

See also the crates docs for more detailed descriptions of the arguments.

LICENSE

MIT