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// 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.component;
using fuchsia.process;
using fuchsia.component.decl;
/// The maximum number of handles that can be passed to a created component.
const MAX_HANDLE_COUNT uint32 = 128;
/// The maximum number of dynamic offers that can target a created component.
const MAX_DYNAMIC_OFFER_COUNT uint32 = 128;
/// The maximum number of children that the a call `ChildIterator.Next`
/// can return.
/// Note, this is not a limit on the number of children that can be added
/// to a component. This is merely a limit for a single invocation of the
/// `Next` method.
const MAX_CHILD_COUNT uint32 = 128;
/// A protocol used by a component instance to manage its own realm, such as for
/// binding to its children.
/// Requests to this protocol are processed in the order they are received.
/// Clients that wish to send requests in parallel should open multiple
/// connections.
/// The component framework provides this service to components that use
/// `fuchsia.component.Realm`.
protocol Realm {
/// Opens the exposed directory of a child component instance. When this
/// function successfully returns, `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). The child component will not start as a
/// result of this call. Instead, starting will occur iff the parent binds
/// to one of the capabilities contained within `exposed_dir`.
/// `exposed_dir` is open as long as `child` exists.
/// Errors:
/// - `INVALID_ARGUMENTS`: `child` is not a valid child reference.
/// - `INSTANCE_NOT_FOUND`: `child` does not exist.
/// - `INSTANCE_CANNOT_RESOLVE`: `child`'s component declaration failed to resolve.
/// - `INSTANCE_DIED`: This realm no longer exists.
OpenExposedDir(resource struct {
child fuchsia.component.decl.ChildRef;
}) -> (struct {}) error 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`.
/// - `INSTANCE_CANNOT_RESOLVE`: `child`'s component declaration failed to resolve
/// in a `SingleRun` collection.
/// - `NO_SPACE`: Could not allocate storage for the new instance.
/// - `INSTANCE_DIED`: This realm no longer exists.
CreateChild(resource struct {
collection fuchsia.component.decl.CollectionRef;
decl fuchsia.component.decl.Child;
args CreateChildArgs;
}) -> (struct {}) error Error;
/// Destroys a dynamically-created component instance. When this function
/// returns, the instance is destroyed and has stopped running. However,
/// cleanup of the component's resources (such as its isolated storage) may
/// happen in the background after this 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(struct {
child fuchsia.component.decl.ChildRef;
}) -> (struct {}) error 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(resource struct {
collection fuchsia.component.decl.CollectionRef;
iter server_end:ChildIterator;
}) -> (struct {}) error Error;
type CreateChildArgs = resource table {
/// The numbered handles to pass to the component instance.
/// Only PA_FD and PA_USER* handles are valid arguments, and inclusion of any other
/// handles will result in an error. This argument is only supported for components
/// in a collection with `SingleRun` durability.
/// If the runner for the component does not support the numbered handles it is
/// expected to close the handles.
1: numbered_handles vector<fuchsia.process.HandleInfo>:MAX_HANDLE_COUNT;
/// Dynamic offers that will target the component instance.
/// Including `OfferDecl`s in this vector will cause additional capabilities
/// to be offered to the newly created child, beyond the `OfferDecl`s in the
/// parent's `ComponentDecl` that target the collection.
/// Any kind of offer (e.g., protocol, directory) can be used as a dynamic
/// offer. Any source that would be valid for a static offer is also valid
/// for a dynamic offer. Additionally, unlike static offers, dynamic offers
/// can use a "sibling" dynamic child component as a source by setting the
/// source to a `ChildRef` that sets the `collection` field.
/// Dynamic offers always target the newly created child component. As a
/// result, `OfferDecl`s in `dynamic_offers` must not set the `target`
/// field, as its value is implied.
/// If either the source (that is, the component named in the `source` field
/// of the `OfferDecl`) or the target of a dynamic offer is destroyed, the
/// offer itself is destroyed simultaneously.
/// In order to set this field to a non-empty value, the collection in which
/// the child component is being created must specify
/// `ComponentDecl.allowed_offers = STATIC_AND_DYNAMIC`.
/// TODO( Implementation is in progress.
2: dynamic_offers vector<fuchsia.component.decl.Offer>:MAX_DYNAMIC_OFFER_COUNT;
/// 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() -> (struct {
children vector<fuchsia.component.decl.ChildRef>:MAX_CHILD_COUNT;