chromium/mojo/public/cpp/bindings/shared_associated_remote.h

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MOJO_PUBLIC_CPP_BINDINGS_SHARED_ASSOCIATED_REMOTE_H_
#define MOJO_PUBLIC_CPP_BINDINGS_SHARED_ASSOCIATED_REMOTE_H_

#include <tuple>

#include "base/memory/scoped_refptr.h"
#include "base/task/sequenced_task_runner.h"
#include "mojo/public/cpp/bindings/associated_remote.h"
#include "mojo/public/cpp/bindings/pending_associated_remote.h"
#include "mojo/public/cpp/bindings/runtime_features.h"
#include "mojo/public/cpp/bindings/shared_remote.h"

namespace mojo {

namespace internal {

SharedRemoteTraits<AssociatedRemote<Interface>>;

}  // namespace internal

// SharedAssociatedRemote wraps a non-thread-safe AssociatedRemote and proxies
// messages to it. Unlike normal AssociatedRemote objects,
// SharedAssociatedRemote is copyable and usable from any thread, but has some
// additional overhead and latency in message transmission as a trade-off.
//
// Async calls are posted to the sequence that the underlying AssociatedRemote
// is bound to, and responses are posted back to the calling sequence. Sync
// calls are dispatched directly if the call is made on the sequence that the
// wrapped AssociatedRemote is bound to, or posted otherwise. It's important to
// be aware that sync calls block both the calling sequence and the bound
// AssociatedRemote's sequence. That means that you cannot make sync calls
// through a SharedAssociatedRemote if the underlying AssociatedRemote is bound
// to a sequence that cannot block, like the IPC thread.
template <typename Interface>
class SharedAssociatedRemote { … };

}  // namespace mojo

#endif  // MOJO_PUBLIC_CPP_BINDINGS_SHARED_ASSOCIATED_REMOTE_H_