sdk/fidl/fuchsia.sys2/decls/child_decl.fidl

// Copyright 2018 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.sys2;

using fuchsia.component;
using fuchsia.url;

/// Statically declares a child component instance.
table ChildDecl {
    /// The name assigned to the child by its parent.
    ///
    /// Must be non-empty, unique among all siblings, and contain only the
    /// following characters: [a-z0-9-_.].
    1: fuchsia.component.name name;

    /// The child component's URL.
    ///
    /// Must be non-empty and a well-formed URL.
    2: fuchsia.url.Url url;

    /// The startup mode for the component instance.
    3: StartupMode startup;

    /// The environment assigned to this child.
    ///
    /// Must be non-empty, reference an environment defined in the containing
    /// `ComponentDecl`, and contain only the following characters:
    /// [a-z0-9-_.].
    4: fuchsia.component.name environment;

    // TODO(fxbug.dev/4051): Provide a way to supply parameters to the child, possibly
    // as command-line arguments, by URL, or maybe in some other way which is
    // orthogonal to other inputs to mitigate confused deputy issues.  Perhaps
    // as a dictionary like we do for runners?
};

/// Describes under what conditions the component may be started.
enum StartupMode {
    /// Start component instance only when another instance binds to it.
    LAZY = 0;
    /// Start component instance as soon as parent starts. This mode is only
    /// supported for statically declared children -- a dynamic instance may only be
    /// started by binding to it.
    EAGER = 1;
};