// Copyright 2019 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.sys.internal;

using fuchsia.io;

/// Service exposed by appmgr that enables a component (such as archivist) to listen for
/// lifecycle events of components in the realm tree.
@discoverable
protocol ComponentEventProvider {
    /// Requests a hook to get lifecycle events for the realm from where this service
    /// was connected to.
    SetListener(resource struct {
        listener client_end:ComponentEventListener;
    });
};

/// Listener for events about the lifecycle of components.
///
/// When the listener is created it will receive `OnStart` calls for all
/// components that were already in the Realm tree. If some sub-realm has a
/// listener attached, events for components under that realm's subtree won't be
/// synthesized.
protocol ComponentEventListener {
    /// Notifies the client that a component has started in the realm.
    OnStart(struct {
        component SourceIdentity;
    });

    /// Notifies the client that a component has stopped.
    OnStop(struct {
        component SourceIdentity;
    });

    /// Notifies the client that the out/diagnostics directory of a component is ready
    /// and provides a handle to it.
    OnDiagnosticsDirReady(resource struct {
        component SourceIdentity;
        directory client_end:fuchsia.io.Directory;
    });
};