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// 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;
/// A protocol used by a component instance to manage its own realm, such as for
/// binding to its children.
/// The component manager provides this service to components that use
/// `fuchsia.sys2.Realm`.
protocol Realm {
/// Binds to a child component instance, causing it to start running if it
/// is not already. When this function successfully returns, `child` is
/// running and `exposed_dir` is bound to a directory that contains the
/// capabilities which the child exposed to its realm via
/// `ComponentDecl.exposes` (specified via "expose" declarations in the
/// component's manifest).
/// `exposed_dir` is a valid channel as long as `child` is running. `child`
/// will remain running until it either stops on its own, or `DestroyChild`
/// causes the child instance to be destroyed.
/// For example, if the child exposes a service `/svc/example.Echo` then
/// `exposed_dir` will contain that service at that path.
/// NOTE: `BindChild` does not support pipelining with `CreateChild`. If
/// `BindChild` is called on an instance before `CreateChild` successfully
/// returns, it may return `INSTANCE_NOT_FOUND`.
/// Errors:
/// - `INVALID_ARGUMENTS`: `child` is not a valid child reference. -
/// - `INSTANCE_NOT_FOUND`: `child` does not exist.
/// - `INSTANCE_CANNOT_START`: `child` was not running and there was an error
/// starting it.
/// - `INSTANCE_CANNOT_RESOLVE`: `child`'s component declaration failed to resolve.
/// - `INSTANCE_DIED`: This realm no longer exists.
BindChild(ChildRef child,
request<> exposed_dir) -> () error fuchsia.component.Error;
/// Creates a child component instance dynamically. When this function
/// returns successfully, the instance exists, but it may not be running.
/// The environment of the child instance is determined by the environment
/// of the collection. `decl` must not set `environment`.
/// Errors:
/// - `INVALID_ARGUMENTS`: `collection` is not a valid reference or `child`
/// is not a valid declaration.
/// - `COLLECTION_NOT_FOUND`: `collection` does not exist.
/// - `INSTANCE_ALREADY_EXISTS`: `` already exists in `collection`.
/// - `NO_SPACE`: Could not allocate storage for the new instance.
/// - `INSTANCE_DIED`: This realm no longer exists.
CreateChild(CollectionRef collection, ChildDecl decl) -> () error fuchsia.component.Error;
/// Destroys a dynamically-created component instance. When this function
/// returns, the client should assume the instance no longer exists.
/// However, some cleanup (such as stopping the component instance or
/// freeing its storage) may be performed in the background after the
/// function returns.
/// Errors:
/// - `INVALID_ARGUMENTS`: `child` is not a valid reference or does not refer
/// to a dynamic instance.
/// - `INSTANCE_NOT_FOUND`: `child` does not exist.
/// - `COLLECTION_NOT_FOUND`: `collection` does not exist.
/// - `INSTANCE_DIED`: This realm no longer exists.
DestroyChild(ChildRef child) -> () error fuchsia.component.Error;
/// Returns an iterator that lists all instances in a collection.
/// NOTE: The results are not guaranteed to be consistent. Instances may be
/// created or destroyed while the iterator is live, but those changes
/// won't be observed by the iterator after this method returns.
/// Errors:
/// - `INVALID_ARGUMENTS`: `collection` is not a valid reference or `iter`
/// does not have `ZX_RIGHT_WAIT`.
/// - `COLLECTION_NOT_FOUND`: `collection` does not exist.
/// - `INSTANCE_DIED`: This realm no longer exists.
/// - If `iter` does not have standard channel rights, this function may
/// return `ACCESS_DENIED` or component manager may close `iter`.
ListChildren(CollectionRef collection, request<ChildIterator> iter) -> ()
error fuchsia.component.Error;
/// A protocol to iterate over the list of children in a realm.
protocol ChildIterator {
/// Advance the iterator and return the next batch of children.
/// Returns a vector of `ChildRef`. Returns an empty vector when there are
/// no more children.
Next() -> (vector<ChildRef> children);