// Copyright 2021 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.diagnostics;

/// Max number of LogInterestSelectors that can be specified via a listener.
const MAX_LOG_SELECTORS uint8 = 64;

/// A specified Interest coupled with its designated target,
type LogInterestSelector = struct {
    /// Matches the components for which the interest will be requested.
    selector ComponentSelector;

    /// The interest level that will be sent to components matching the selector.
    interest Interest;
};

/// This protocol allows clients to modify the logging behavior of components
/// in the system.
@discoverable
protocol LogSettings {
    /// Requests a change in interest for the matched components.
    ///
    /// Each component holds a set of requested interests.
    ///
    /// When a new request on LogSettings#RegisterInterest is received,
    /// the sets for matched components receive the new minimum interest.
    /// If the interest is less than the previous minimum interest, then a
    /// `RegisterInterest` request is sent with the new minimum interest.
    ///
    /// If a connection to `LogSettings` sends another `RegisterInterest`
    /// request, its previous interest request will be undone.
    ///
    /// When the connection to `LogSettings` is finished, the interests are
    /// undone. Each matched component minimum interest is updated with the
    /// new minimum interest in the set.
    RegisterInterest(struct {
        selectors vector<LogInterestSelector>:MAX_LOG_SELECTORS;
    });
};