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// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROMECAST_MOJO_REMOTE_INTERFACES_H_
#define CHROMECAST_MOJO_REMOTE_INTERFACES_H_
#include "base/sequence_checker.h"
#include "chromecast/mojo/mojom/remote_interfaces.mojom.h"
#include "mojo/public/cpp/bindings/pending_receiver.h"
#include "mojo/public/cpp/bindings/remote.h"
namespace chromecast {
// Client helper object which wraps a mojo::Remote<mojom::RemoteInterfaces> and
// provides convenience methods for binding local Remote stubs.
//
// =============================================================================
// Example Usage
// =============================================================================
//
// From a service, create a pending RemoteInterfaces, such as from
// InterfaceBundle:
//
// InterfaceBundle bundle;
// bundle.AddInterface<mojom::Foo>(GetFooImpl());
// bundle.AddInterface<mojom::Bar>(GetBarImpl());
// mojo::PendingRemote<mojom::RemoteInterfaces> pending_provider =
// bundle.CreateRemote();
//
// In a different service, we can use RemoteInterfaces to wrap
// |pending_provider| and access the interfaces that were added:
//
// RemoteService::InjectInterfaces(
// mojo::PendingRemote<mojom::RemoteInterfaces> pending_provider) {
// RemoteInterfaces provider(std::move(pending_provider));
// mojo::Remote<mojom::Bar> bar = bundle.GetRemote<mojom::Bar>();
// bar->DoBarStuff();
// }
class RemoteInterfaces {
public:
RemoteInterfaces();
explicit RemoteInterfaces(
mojo::PendingRemote<mojom::RemoteInterfaces> provider);
~RemoteInterfaces();
RemoteInterfaces(const RemoteInterfaces&) = delete;
RemoteInterfaces& operator=(const RemoteInterfaces&) = delete;
// Late-binds a provider if one was not injected on creation.
void SetProvider(mojo::PendingRemote<mojom::RemoteInterfaces> provider);
// Exposes interfaces to a remote provider.
mojo::PendingRemote<mojom::RemoteInterfaces> Forward();
// Gets the currently unbound receiver to pass to a remote provider. There
// must not already be a receiver bound to this class.
mojo::PendingReceiver<mojom::RemoteInterfaces> GetReceiver();
// ===========================================================================
// Interface binding methods: After binding, the Remotes/PendingRemotes which
// are bound are guaranteed to be bound and connected (i.e. remote.is_bound()
// and remote.is_connected() will return true immediately). Clients can safely
// start issuing method calls at this point. However, if the remote provider
// does not fulfill the request, then the Remote/PendingRemote will become
// disconnected (remote.is_connected() == false), but still be bound.
// ===========================================================================
// Binds an <Interface> implementation in the remote provider.
template <typename Interface>
void Bind(mojo::PendingReceiver<Interface> receiver) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
remote_provider_->BindInterface(Interface::Name_, receiver.PassPipe());
}
// Binds a new message pipe to |remote|, and passes the request to the remote
// provider.
template <typename Interface>
void BindNewPipe(mojo::Remote<Interface>* remote) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
auto pending_receiver = remote->BindNewPipeAndPassReceiver();
Bind(std::move(pending_receiver));
}
// Dispenses a mojo::Remote<Interface> which is bound by the remote provider.
template <typename Interface>
mojo::Remote<Interface> CreateRemote() {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
mojo::Remote<Interface> remote;
BindNewPipe(&remote);
return remote;
}
private:
void Init();
mojo::Remote<mojom::RemoteInterfaces> remote_provider_;
// Temporary pending receiver which allows the client to immediately
// start acquiring remote interfaces while we wait for an implementation
// to be provided.
mojo::PendingReceiver<mojom::RemoteInterfaces> waiting_receiver_;
SEQUENCE_CHECKER(sequence_checker_);
};
} // namespace chromecast
#endif // CHROMECAST_MOJO_REMOTE_INTERFACES_H_