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/*
* Copyright © 2012 Canonical Ltd.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Authored by: Thomas Voß <thomas.voss@canonical.com>
*/
#ifndef CORE_DBUS_RESULT_H_
#define CORE_DBUS_RESULT_H_
#include <core/dbus/codec.h>
#include <core/dbus/error.h>
#include <core/dbus/message.h>
#include <stdexcept>
#include <string>
namespace core
{
namespace dbus
{
/**
* @brief Wraps a remote method invocation, its error state and result.
* @tparam T Result type.
*/
template<typename T>
class Result
{
public:
/**
* @brief from_message parses the result from a raw dbus message.
* @throw std::runtime_error in case of errors.
* @param message The message to parse the result from.
*/
inline static Result from_message(const Message::Ptr& message)
{
Result result;
switch(message->type())
{
case Message::Type::method_call:
throw std::runtime_error("Cannot construct result from method call");
break;
case Message::Type::signal:
throw std::runtime_error("Cannot construct result from signal");
break;
case Message::Type::error:
result.d.error = message->error();
break;
case Message::Type::method_return:
message->reader() >> result.d.value;
break;
default:
break;
}
return result;
}
/**
* @brief Check if the result is an error.
* @return true if the invocation returned an error, false otherwise.
*/
inline bool is_error() const
{
return static_cast<bool>(d.error);
}
/**
* @brief Accesses the contained error message if any.
* @return A string describing the error state. Can be empty if no error occured.
*/
inline const Error& error() const
{
return d.error;
}
/**
* @brief Non-mutable access to the contained value.
* @return A non-mutable reference to the contained value.
*/
inline const T& value() const
{
return d.value;
}
private:
struct Private
{
Error error;
T value;
} d;
};
/**
* @brief Wraps a remote method invocation and its error state. Template specialization for void results.
*/
template<>
class Result<void>
{
public:
/**
* @brief from_message parses the result from a raw dbus message.
* @throw std::runtime_error in case of errors.
* @param message The message to parse the result from.
*/
inline static Result from_message(const Message::Ptr& message)
{
Result result;
switch(message->type())
{
case Message::Type::method_call:
throw std::runtime_error("Cannot construct result from method call");
break;
case Message::Type::signal:
throw std::runtime_error("Cannot construct result from signal");
break;
case Message::Type::error:
result.d.error = message->error();
break;
case Message::Type::method_return:
default:
break;
}
return result;
}
/**
* @brief Check if the result is an error.
* @return true if the invocation returned an error, false otherwise.
*/
inline bool is_error() const
{
return static_cast<bool>(d.error);
}
/**
* @brief Accesses the contained error message if any.
* @return A string describing the error state. Can be empty if no error occured.
*/
inline const Error& error() const
{
return d.error;
}
private:
struct Private
{
Error error;
} d;
};
}
}
#endif // CORE_DBUS_RESULT_H_
|
