diff --git a/src/wayland/server/DESIGN.md b/src/wayland/server/DESIGN.md new file mode 100644 index 0000000000..28f4dbba88 --- /dev/null +++ b/src/wayland/server/DESIGN.md @@ -0,0 +1,84 @@ +# History + +We started out with one method of generting classes. We then ported to a new approach of using QtWaylandScanner to reduce a lot of boiler plate. + +New classes should use the new approach. + +# New Approach + +A public facing PIMPL class which should inherit from QObject. +A private class that should inherit from QtWaylandServer::interface_name which is auto-generated. This will manage individual resources, handle callbacks and QString conversions. + +Class Names should map to the interface name in UpperCamelCase. +Where a V1 exists in the interface name, this should be mirrored in the file and class name. + +An implementation should handle all versions of a given interface, but not different interfaces which represent different versions. + +(i.e zxdg_output_manager_v1 versions 1 2 and 3 would be wrapped in one class XdgOutputManagerV1Interface. A zxdg_output_manager_v2 protocol would be exposed as a new public class XdgOutputManagerV2Interface) + +# Implementations + +There are 3 modes of operation happening within the exported classes of KWaylandServer + +The generated classes can behave in all these modes, it is up to our implementation to use the correct methods. + +## Globals +e.g BlurManager + +This represents an object listed by the Display class. +Use the interface_name::(wl_display*, int version) constructor within the private class to create an instance. + + +## Server-managed multicasting resources +e.g XdgOutput + +This is where one QObject represents multiple Resources. + +Use the method +```cpp +QtWaylandServer::interface_name::add(client, id, version) +``` + +to create a a new Resource instance managed by this object. + +Use the event method with the wl_resource* overload to send events. + +```cpp +for (auto resource : resourceMap()) +{ + send_some_method(resource->handle, arg1, arg2); +} +``` + +methods to send requests to all clients. + +## Client-owned Resources: + +e.g BlurInterface + +This is where one instance of our public class represents a single resource. Typically the lifespan of the exported class matches our resource. + +In the private class use the QtWaylandServer::interface_name(wl_resource*) constructor to create a wrapper bound to a specific resource. + +Use +```cpp +send_some_method(arg1, args2) +``` +methods of the privateClass to send events to the resource set in the constructor + + +## Other hooks + +`_bind_resource` is called whenever a resource is bound. This exists for all generated classes in all the operating modes + +`_destroy_resource` is a hook called whenever a resource has been unbound. +Note one should not call wl_resource_destroy in this hook. + +## Resource destructors + +destructors (tagged with type="destructor" in the XML) are not handled specially in QtWayland it is up to the class implementation to implement the event handler and call +```cpp +wl_resource_destroy(resource->handle) +``` +in the relevant method +