blob: 1324f99efc9a3803fab28630fe46b49f9604216c [file] [log] [blame]
// 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.
#include <string>
#include <fuchsia/modular/cpp/fidl.h>
#include <lib/fidl/cpp/binding.h>
#include <lib/fit/function.h>
#include "lib/fxl/macros.h"
namespace modular {
// MessageQueueClient is a wrapper class for using fuchsia.modular.MessageQueue
// in a more convinient way. This class represents messages as a std::string,
// which the underlying fidl interface may not.
// Usage:
// // 1. Obtain message queue and use it with MessageQueueClient.
// MessageQueueClient message_queue;
// component_context->ObtainMessageQueue("my_msg_q",
// message_queue.NewRequest());
// // 2. Register receiver. New messages are sent to the supplied callback until
// // the MessageQueueClient goes out of scope, or the receiver is
// // unregistered. To unregister the receiver, call this method with a
// // |nullptr| receiver.
// message_queue.RegisterReceiver([] (std::string msg, fit::function<void> ack){
// ack(); // Acknowledge message receipt. We will continue to have new
// // messages delivered to this callback.
// FXL_LOG(INFO) << "new message: " << msg;
// });
class MessageQueueClient : public fuchsia::modular::MessageReader {
using ReceiverCallback =
fit::function<void(std::string message, fit::function<void()> ack)>;
// Creates a new interface pair, binds one end to this object and returns the
// request side. The previous message queue and receiver are unbound.
fidl::InterfaceRequest<fuchsia::modular::MessageQueue> NewRequest();
// Register a receiver callback, which will be called everytime there is a new
// message. The receiver is supplied the message and an acknowledgement
// callback which the receiver must call, to acknowledge that the message has
// been processed and does not need to be received again. Supplying a
// |nullptr| will unregister the previous receiver.
void RegisterReceiver(ReceiverCallback receiver);
// Returns a token for this message queue, which is used to send messages
// to this message queue.
void GetToken(std::function<void(fidl::StringPtr)> callback);
// |fuchsia::modular::MessageReader|
void OnReceive(fuchsia::mem::Buffer message,
std::function<void()> ack) override;
fuchsia::modular::MessageQueuePtr queue_;
fidl::Binding<fuchsia::modular::MessageReader> reader_;
ReceiverCallback receiver_;
} // namespace modular