chromecast/external_mojo/external_service_support/external_connector.h

// Copyright 2019 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_EXTERNAL_MOJO_EXTERNAL_SERVICE_SUPPORT_EXTERNAL_CONNECTOR_H_
#define CHROMECAST_EXTERNAL_MOJO_EXTERNAL_SERVICE_SUPPORT_EXTERNAL_CONNECTOR_H_

#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "base/callback.h"
#include "base/macros.h"
#include "base/sequence_checker.h"
#include "chromecast/external_mojo/public/mojom/connector.mojom.h"
#include "mojo/public/cpp/bindings/interface_ptr.h"
#include "mojo/public/cpp/bindings/interface_request.h"
#include "mojo/public/cpp/system/message_pipe.h"

namespace chromecast {
namespace external_service_support {
class ExternalService;

// Interface to the Mojo broker, allowing services to be registered and other
// processes to bind to registered services. Once any public methods are called
// on an instance of this class, that instance is bound to the calling thread.
//
// To use the same interface on another thread, call Clone() and pass the new
// instance to the desired thread before calling any public methods on it.
class ExternalConnector {
 public:
  static void Connect(
      const std::string& broker_path,
      base::OnceCallback<void(std::unique_ptr<ExternalConnector>)> callback);

  explicit ExternalConnector(
      external_mojo::mojom::ExternalConnectorPtr connector);
  explicit ExternalConnector(
      external_mojo::mojom::ExternalConnectorPtrInfo unbound_state);
  ~ExternalConnector();

  // Sets the callback that will be called if this class loses its connection to
  // the Mojo broker. Note that once the connection is lost, this instance
  // becomes nonfunctional (all public methods are no-ops); a new connection
  // must be made instead.
  void set_connection_error_callback(base::OnceClosure callback) {
    connection_error_callback_ = std::move(callback);
  }

  // Registers a service that other Mojo processes/services can bind to. Others
  // can call BindInterface(|service_name|, interface_name) to bind to this
  // |service|.
  void RegisterService(const std::string& service_name,
                       ExternalService* service);
  void RegisterService(const std::string& service_name,
                       external_mojo::mojom::ExternalServicePtr service_ptr);

  // Asks the Mojo broker to bind to a matching interface on the service with
  // the given |service_name|. If the service does not yet exist, the binding
  // will remain in progress until the service is registered.
  template <typename Interface>
  void BindInterface(const std::string& service_name,
                     mojo::InterfacePtr<Interface>* ptr) {
    BindInterface(service_name, Interface::Name_,
                  mojo::MakeRequest(ptr).PassMessagePipe());
  }

  void BindInterface(const std::string& service_name,
                     const std::string& interface_name,
                     mojo::ScopedMessagePipeHandle interface_pipe);

  // Creates a new instance of this class which may be passed to another thread.
  // The returned object may be passed across sequences until any of its public
  // methods are called, at which point it becomes bound to the calling
  // sequence.
  std::unique_ptr<ExternalConnector> Clone();

  // Sends a request for a Chromium ServiceManager connector.
  void SendChromiumConnectorRequest(mojo::ScopedMessagePipeHandle request);

  // Query the list of available services from this connector.
  void QueryServiceList(
      base::OnceCallback<
          void(std::vector<
               chromecast::external_mojo::mojom::ExternalServiceInfoPtr>)>
          callback);

 private:
  void OnConnectionError();
  bool BindConnectorIfNecessary();

  external_mojo::mojom::ExternalConnectorPtr connector_;
  external_mojo::mojom::ExternalConnectorPtrInfo unbound_state_;
  base::OnceClosure connection_error_callback_;

  SEQUENCE_CHECKER(sequence_checker_);

  DISALLOW_COPY_AND_ASSIGN(ExternalConnector);
};

}  // namespace external_service_support
}  // namespace chromecast

#endif  // CHROMECAST_EXTERNAL_MOJO_EXTERNAL_SERVICE_SUPPORT_EXTERNAL_CONNECTOR_H_