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// Copyright 2014 The Chromium OS 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 LIBBRILLO_BRILLO_DBUS_DBUS_METHOD_RESPONSE_H_
#define LIBBRILLO_BRILLO_DBUS_DBUS_METHOD_RESPONSE_H_
#include <memory>
#include <string>
#include <utility>
#include <base/bind.h>
#include <base/location.h>
#include <base/macros.h>
#include <brillo/brillo_export.h>
#include <brillo/dbus/dbus_param_writer.h>
#include <brillo/errors/error.h>
#include <dbus/exported_object.h>
#include <dbus/message.h>
namespace brillo {
class Error;
namespace dbus_utils {
using ResponseSender = ::dbus::ExportedObject::ResponseSender;
// DBusMethodResponseBase is a helper class used with asynchronous D-Bus method
// handlers to encapsulate the information needed to send the method call
// response when it is available.
class BRILLO_EXPORT DBusMethodResponseBase {
public:
DBusMethodResponseBase(::dbus::MethodCall* method_call,
ResponseSender sender);
DBusMethodResponseBase(DBusMethodResponseBase&& other)
: sender_(std::exchange(
other.sender_,
base::Bind([](std::unique_ptr<dbus::Response> response) {
LOG(DFATAL)
<< "Empty DBusMethodResponseBase attempts to send a response";
}))),
method_call_(std::exchange(other.method_call_, nullptr)) {}
DBusMethodResponseBase& operator=(DBusMethodResponseBase&& other) = delete;
virtual ~DBusMethodResponseBase();
// Sends an error response. Marshals the |error| object over D-Bus.
// If |error| is from the "dbus" error domain, takes the |error_code| from
// |error| and uses it as the DBus error name.
// For error is from other domains, the full error information (domain, error
// code, error message) is encoded into the D-Bus error message and returned
// to the caller as "org.freedesktop.DBus.Failed".
virtual void ReplyWithError(const brillo::Error* error);
// Constructs brillo::Error object from the parameters specified and send
// the error information over D-Bus using the method above.
virtual void ReplyWithError(const base::Location& location,
const std::string& error_domain,
const std::string& error_code,
const std::string& error_message);
// Sends a raw D-Bus response message.
void SendRawResponse(std::unique_ptr<::dbus::Response> response);
// Creates a custom response object for the current method call.
std::unique_ptr<::dbus::Response> CreateCustomResponse() const;
// Checks if the response has been sent already.
bool IsResponseSent() const;
protected:
void CheckCanSendResponse() const;
// Aborts the method execution. Does not send any response message.
void Abort();
private:
// A callback to be called to send the method call response message.
ResponseSender sender_;
// |method_call_| is actually owned by |sender_| (it is embedded as unique_ptr
// in the bound parameter list in the Callback). We set it to nullptr after
// the method call response has been sent to ensure we can't possibly try
// to send a response again somehow.
::dbus::MethodCall* method_call_;
};
// DBusMethodResponse is an explicitly-typed version of DBusMethodResponse.
// Using DBusMethodResponse<Types...> indicates the types a D-Bus method
// is expected to return.
template<typename... Types>
class DBusMethodResponse : public DBusMethodResponseBase {
public:
// Make the base class's custom constructor available to DBusMethodResponse.
using DBusMethodResponseBase::DBusMethodResponseBase;
// Sends the a successful response. |return_values| can contain a list
// of return values to be sent to the caller.
virtual void Return(const Types&... return_values) {
CheckCanSendResponse();
auto response = CreateCustomResponse();
::dbus::MessageWriter writer(response.get());
DBusParamWriter::Append(&writer, return_values...);
SendRawResponse(std::move(response));
}
};
} // namespace dbus_utils
} // namespace brillo
#endif // LIBBRILLO_BRILLO_DBUS_DBUS_METHOD_RESPONSE_H_