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sdbus-cpp/include/sdbus-c++/IConnection.h
Taras Zaporozhets 299e6940cd Improve ABI
2022-10-30 18:17:51 +01:00

470 lines
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C++

/**
* (C) 2016 - 2021 KISTLER INSTRUMENTE AG, Winterthur, Switzerland
* (C) 2016 - 2022 Stanislav Angelovic <stanislav.angelovic@protonmail.com>
*
* @file IConnection.h
*
* Created on: Nov 8, 2016
* Project: sdbus-c++
* Description: High-level D-Bus IPC C++ library based on sd-bus
*
* This file is part of sdbus-c++.
*
* sdbus-c++ is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 2.1 of the License, or
* (at your option) any later version.
*
* sdbus-c++ 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 sdbus-c++. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef SDBUS_CXX_ICONNECTION_H_
#define SDBUS_CXX_ICONNECTION_H_
#include <sdbus-c++/TypeTraits.h>
#include <string>
#include <memory>
#include <chrono>
#include <cstdint>
#include <optional>
namespace sdbus {
/********************************************//**
* @class IConnection
*
* An interface to D-Bus bus connection. Incorporates implementation
* of both synchronous and asynchronous D-Bus I/O event loop.
*
* All methods throw sdbus::Error in case of failure. All methods in
* this class are thread-aware, but not thread-safe.
*
***********************************************/
class IConnection
{
public:
/*!
* Poll Data for external event loop implementations.
*
* To integrate sdbus with your app's own custom event handling system
* you can use this method to query which file descriptors, poll events
* and timeouts you should add to your app's poll(2), or select(2)
* call in your main event loop.
*
* If you are unsure what this all means then use
* enterEventLoop() or enterEventLoopAsync() instead.
*
* See: getEventLoopPollData()
*/
struct PollData
{
/*!
* The read fd to be monitored by the event loop.
*/
int fd;
/*!
* The events to use for poll(2) alongside fd.
*/
short int events;
/*!
* Absolute timeout value in micro seconds and based of CLOCK_MONOTONIC.
*/
uint64_t timeout_usec;
/*!
* The read fd to be monitored by the event loop.
*/
int event_fd;
/*!
* Get the event poll timeout.
*
* The timeout is an absolute value based of CLOCK_MONOTONIC.
*
* @return a duration since the CLOCK_MONOTONIC epoch started.
*/
[[nodiscard]] std::chrono::microseconds getAbsoluteTimeout() const
{
return std::chrono::microseconds(timeout_usec);
}
/*!
* Get the timeout as relative value from now
*
* @return std::nullopt if the timeout is indefinite. A duration otherwise.
*/
[[nodiscard]] std::optional<std::chrono::microseconds> getRelativeTimeout() const;
/*!
* Get a converted, relative timeout which can be passed as argument 'timeout' to poll(2)
*
* @return -1 if the timeout is indefinite. 0 if the poll(2) shouldn't block. An integer in milli
* seconds otherwise.
*/
[[nodiscard]] int getPollTimeout() const;
};
virtual ~IConnection() = default;
/*!
* @brief Requests D-Bus name on the connection
*
* @param[in] name Name to request
*
* @throws sdbus::Error in case of failure
*/
virtual void requestName(const std::string& name) = 0;
/*!
* @brief Releases D-Bus name on the connection
*
* @param[in] name Name to release
*
* @throws sdbus::Error in case of failure
*/
virtual void releaseName(const std::string& name) = 0;
/*!
* @brief Retrieve the unique name of a connection. E.g. ":1.xx"
*
* @throws sdbus::Error in case of failure
*/
virtual std::string getUniqueName() const = 0;
/*!
* @brief Enters I/O event loop on this bus connection
*
* The incoming D-Bus messages are processed in the loop. The method
* blocks indefinitely, until unblocked through leaveEventLoop().
*
* @throws sdbus::Error in case of failure
*/
virtual void enterEventLoop() = 0;
/*!
* @brief Enters I/O event loop on this bus connection in a separate thread
*
* The same as enterEventLoop, except that it doesn't block
* because it runs the loop in a separate, internally managed thread.
*/
virtual void enterEventLoopAsync() = 0;
/*!
* @brief Leaves the I/O event loop running on this bus connection
*
* This causes the loop to exit and frees the thread serving the loop
*
* @throws sdbus::Error in case of failure
*/
virtual void leaveEventLoop() = 0;
/*!
* @brief Adds an ObjectManager at the specified D-Bus object path
*
* Creates an ObjectManager interface at the specified object path on
* the connection. This is a convenient way to interrogate a connection
* to see what objects it has.
*
* This call creates a floating registration. The ObjectManager will
* be there for the object path until the connection is destroyed.
*
* Another, recommended way to add object managers is directly through
* IObject API.
*
* @throws sdbus::Error in case of failure
*/
[[deprecated("Use one of other addObjectManager overloads")]] virtual void addObjectManager(const std::string& objectPath) = 0;
/*!
* @brief Returns fd, I/O events and timeout data you can pass to poll
*
* To integrate sdbus with your app's own custom event handling system
* (without the requirement of an extra thread), you can use this
* method to query which file descriptors, poll events and timeouts you
* should add to your app's poll call in your main event loop. If these
* file descriptors signal, then you should call processPendingRequest
* to process the event. This means that all of sdbus's callbacks will
* arrive on your app's main event thread (opposed to on a thread created
* by sdbus-c++). If you are unsure what this all means then use
* enterEventLoop() or enterEventLoopAsync() instead.
*
* To integrate sdbus-c++ into a gtk app, pass the file descriptor returned
* by this method to g_main_context_add_poll.
*
* @throws sdbus::Error in case of failure
*/
virtual PollData getEventLoopPollData() const = 0;
/*!
* @brief Process a pending request
*
* @returns true if an event was processed, false if poll should be called
*
* Processes a single dbus event. All of sdbus-c++'s callbacks will be called
* from within this method. This method should ONLY be used in conjuction
* with getEventLoopPollData().
* This method returns true if an I/O message was processed. This you can try
* to call this method again before going to poll on I/O events. The method
* returns false if no operations were pending, and the caller should then
* poll for I/O events before calling this method again.
* enterEventLoop() and enterEventLoopAsync() will call this method for you,
* so there is no need to call it when using these. If you are unsure what
* this all means then don't use this method.
*
* @throws sdbus::Error in case of failure
*/
virtual bool processPendingRequest() = 0;
/*!
* @brief Sets general method call timeout
*
* @param[in] timeout Timeout value in microseconds
*
* General method call timeout is used for all method calls upon this connection.
* Method call-specific timeout overrides this general setting.
*
* Supported by libsystemd>=v240.
*
* @throws sdbus::Error in case of failure
*/
virtual void setMethodCallTimeout(uint64_t timeout) = 0;
/*!
* @copydoc IConnection::setMethodCallTimeout(uint64_t)
*/
template <typename _Rep, typename _Period>
void setMethodCallTimeout(const std::chrono::duration<_Rep, _Period>& timeout);
/*!
* @brief Gets general method call timeout
*
* @return Timeout value in microseconds
*
* Supported by libsystemd>=v240.
*
* @throws sdbus::Error in case of failure
*/
virtual uint64_t getMethodCallTimeout() const = 0;
/*!
* @brief Adds an ObjectManager at the specified D-Bus object path
*
* Creates an ObjectManager interface at the specified object path on
* the connection. This is a convenient way to interrogate a connection
* to see what objects it has.
*
* This call creates a floating registration. The ObjectManager will
* be there for the object path until the connection is destroyed.
*
* Another, recommended way to add object managers is directly through
* IObject API.
*
* @throws sdbus::Error in case of failure
*/
virtual void addObjectManager(const std::string& objectPath, floating_slot_t) = 0;
/*!
* @brief Adds a match rule for incoming message dispatching
*
* @param[in] match Match expression to filter incoming D-Bus message
* @param[in] callback Callback handler to be called upon incoming D-Bus message matching the rule
* @return RAII-style slot handle representing the ownership of the subscription
*
* The method installs a match rule for messages received on the specified bus connection.
* The syntax of the match rule expression passed in match is described in the D-Bus specification.
* The specified handler function callback is called for each incoming message matching the specified
* expression. The match is installed synchronously when connected to a bus broker, i.e. the call
* sends a control message requested the match to be added to the broker and waits until the broker
* confirms the match has been installed successfully.
*
* Simply let go of the slot instance to uninstall the match rule from the bus connection. The slot
* must not outlive the connection for the slot is associated with it.
*
* For more information, consult `man sd_bus_add_match`.
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] virtual Slot addMatch(const std::string& match, message_handler callback) = 0;
/*!
* @brief Adds a floating match rule for incoming message dispatching
*
* @param[in] match Match expression to filter incoming D-Bus message
* @param[in] callback Callback handler to be called upon incoming D-Bus message matching the rule
* @param[in] Floating slot tag
*
* The method installs a floating match rule for messages received on the specified bus connection.
* Floating means that the bus connection object owns the match rule, i.e. lifetime of the match rule
* is bound to the lifetime of the bus connection.
*
* Refer to the @c addMatch(const std::string& match, message_handler callback) documentation for more
* information.
*
* @throws sdbus::Error in case of failure
*/
virtual void addMatch(const std::string& match, message_handler callback, floating_slot_t) = 0;
/*!
* @copydoc IConnection::enterEventLoop()
*
* @deprecated This function has been replaced by enterEventLoop()
*/
[[deprecated("This function has been replaced by enterEventLoop()")]] void enterProcessingLoop();
/*!
* @copydoc IConnection::enterProcessingLoopAsync()
*
* @deprecated This function has been replaced by enterEventLoopAsync()
*/
[[deprecated("This function has been replaced by enterEventLoopAsync()")]] void enterProcessingLoopAsync();
/*!
* @copydoc IConnection::leaveProcessingLoop()
*
* @deprecated This function has been replaced by leaveEventLoop()
*/
[[deprecated("This function has been replaced by leaveEventLoop()")]] void leaveProcessingLoop();
/*!
* @copydoc IConnection::getProcessLoopPollData()
*
* @deprecated This function has been replaced by getEventLoopPollData()
*/
[[deprecated("This function has been replaced by getEventLoopPollData()")]] PollData getProcessLoopPollData() const;
};
template <typename _Rep, typename _Period>
inline void IConnection::setMethodCallTimeout(const std::chrono::duration<_Rep, _Period>& timeout)
{
auto microsecs = std::chrono::duration_cast<std::chrono::microseconds>(timeout);
return setMethodCallTimeout(microsecs.count());
}
inline void IConnection::enterProcessingLoop()
{
enterEventLoop();
}
inline void IConnection::enterProcessingLoopAsync()
{
enterEventLoopAsync();
}
inline void IConnection::leaveProcessingLoop()
{
leaveEventLoop();
}
inline IConnection::PollData IConnection::getProcessLoopPollData() const
{
return getEventLoopPollData();
}
/*!
* @brief Creates/opens D-Bus system bus connection
*
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createConnection();
/*!
* @brief Creates/opens D-Bus system bus connection with a name
*
* @param[in] name Name to request on the connection after its opening
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createConnection(const std::string& name);
/*!
* @brief Creates/opens D-Bus session bus connection when in a user context, and a system bus connection, otherwise.
*
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createDefaultBusConnection();
/*!
* @brief Creates/opens D-Bus session bus connection with a name when in a user context, and a system bus connection with a name, otherwise.
*
* @param[in] name Name to request on the connection after its opening
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createDefaultBusConnection(const std::string& name);
/*!
* @brief Creates/opens D-Bus system bus connection
*
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createSystemBusConnection();
/*!
* @brief Creates/opens D-Bus system bus connection with a name
*
* @param[in] name Name to request on the connection after its opening
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createSystemBusConnection(const std::string& name);
/*!
* @brief Creates/opens D-Bus session bus connection
*
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createSessionBusConnection();
/*!
* @brief Creates/opens D-Bus session bus connection with a name
*
* @param[in] name Name to request on the connection after its opening
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createSessionBusConnection(const std::string& name);
/*!
* @brief Creates/opens D-Bus session bus connection at a custom address
*
* @param[in] address ";"-separated list of addresses of bus brokers to try to connect
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*
* Consult manual pages for `sd_bus_set_address` of the underlying sd-bus library for more information.
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createSessionBusConnectionWithAddress(const std::string& address);
/*!
* @brief Creates/opens D-Bus system connection on a remote host using ssh
*
* @param[in] host Name of the host to connect
* @return Connection instance
*
* @throws sdbus::Error in case of failure
*/
[[nodiscard]] std::unique_ptr<sdbus::IConnection> createRemoteSystemBusConnection(const std::string& host);
}
#endif /* SDBUS_CXX_ICONNECTION_H_ */