public/lib/netemul/fidl/bus.fidl

library fuchsia.netemul.bus;

/// Simple data structure passed on netemul bus.
struct Event {
    /// User-defined event code.
    int32 code;
    /// Optional string message.
    string? message;
    /// Optional serialized arguments.
    vector<uint8>? arguments;
};

/// Represents a named bus:
///    a bus is a broadcast pub/sub network that distributes Events.
///    Events are not stored, only forwarded to attached clients.
interface Bus {
    /// Publishes event on the bus.
    Publish(Event data);
    /// Publishes data on bus and only returns when data has been dispatched.
    /// Use this if you need guarantees that the data was broadcast before continuing.
    /// Note that this ensures that the data will be *published* to all listening clients,
    /// but it cannot guarantee that all clients will have observed the event before it returns.
    EnsurePublish(Event data) -> ();
    /// Notifies client of new event.
    -> OnBusData(Event data);
    /// Get list of named clients.
    GetClients() -> (vector<string> clients);
    /// Notifies a client is now attached.
    -> OnClientAttached(string client);
    /// Notifies a client was detached.
    -> OnClientDetached(string client);
};

/// The bus manager is the entry point to attach a client to a bus.
/// The client's 'ticket' to remain on the bus is the channel obtained through the 'Subscribe' call.
[Discoverable]
interface BusManager {
    /// Subscribes to bus 'busName' with a given client name.
    /// Duplicate client names are disallowed and will cause the request to return unfulfilled.
    Subscribe(string busName, string clientName, request<Bus> bus);
};