Inheritance diagram for SocketClient:

Classes
struct	AddrInfoDeleter
	Helper structure for creating a unique_ptr for struct addrinfo pointers. More...

Public Types
enum class	Attempt : uint8_t { RECONNECT , INITIATE_MDNS , CONNECT_MDNS , CONNECT_STATIC , WAIT_RETRY , FAILED_EXIT }
	This enum represents individual states of this state flow that we can branch to. More...

typedef std::unique_ptr< struct addrinfo, AddrInfoDeleter >	AddrinfoPtr
	Custom unique pointer that knows how to delete a struct addrinfo.

Public Member Functions
	SocketClient (Service service, ExecutorBase connect_executor, ExecutorBase mdns_executor, std::unique_ptr< SocketClientParams > params, std::function< void(int, Notifiable )> connect_callback)
	Constructor.

	~SocketClient ()
	Destructor.

void	reset_params (std::unique_ptr< SocketClientParams > params)
	Updates the parameter structure for this socket client.

void	shutdown ()
	Shutdown the client so that it can be deleted.

bool	is_connected ()

bool	is_shutdown ()

void	start_shutdown ()
	Request that this client shutdown and exit the other thread.

Public Member Functions inherited from StateFlowBase
void	run () override
	Callback from the executor.

void	notify () override
	Wakeup call arrived.

Service *	service ()
	Return a pointer to the service I am bound to.

Public Member Functions inherited from Executable
void	test_deletion ()

Public Member Functions inherited from QMember
void	init ()
	Initiailize a QMember, in place of a public placement construction.

Static Public Member Functions
static int	connect (const char *host, int port)
	Connects a tcp socket to the specified remote host:port.

static int	connect (const char host, const char port_str)
	Connects a tcp socket to the specified remote host:port.

static int	connect (struct addrinfo *addr)
	Connects a tcp socket to the specified remote address.

static bool	address_to_string (struct addrinfo addr, string host, int *port)
	Converts a struct addrinfo to a dotted-decimal notation IP address.

static AddrinfoPtr	string_to_address (const char *host, int port)
	Converts a hostname string and port number to a struct addrinfo.

static AddrinfoPtr	string_to_address (const char host, const char port_str)
	Converts a hostname string (or null) and port number (or service name) to a struct addrinfo.

Static Public Member Functions inherited from StateFlowBase
template<class T , typename... Args>
static void	invoke_subflow_and_ignore_result (FlowInterface< Buffer< T > > *target_flow, Args &&... args)
	Calls a helper flow to perform some actions.

Private Member Functions
void	prepare_strategy ()
	Parses the params_ configuration and fills in strategyConfig_.

Action	start_connection ()
	Main entry point of the connection process.

Action	next_step ()
	Execute the next step of the strategy.

Action	try_schedule_connect (SocketClientParams::LogMessage log, string host, int port)
	Helper function to schedule asynchronous connect on a separate executor.

void	connect_blocking (const string &host, int port)
	Called on the connect executor.

Action	connect_complete ()
	State that gets invoked once the reconnect attempt is complete.

Action	connected ()
	State that gets called when we have a completed connection in fd_.

string	to_string (const char *p)
	Turns a parameter to a string.

Action	start_mdns ()
	State that initiates the mdns lookup asynchronously.

void	mdns_lookup (string mdns_hostname, string mdns_service)
	Synchronous function that runs on the mdns executor.

Action	wait_and_connect_mdns ()
	Blocks the flow until mdns lookup is complete, then connects to the resulting address.

Action	connect_mdns ()
	Takes the address from the mdns lookup and connects to it if it is valid.

Action	failed_oneshot ()
	Last state in the connection sequence, when everything failed, but the caller wanted one shot only.

Action	wait_retry ()
	Last state in the connection sequence, when everything failed: sleeps until the timeout specified in the params, then goes back to the start_connection.

Action	sleep_done ()

	DISALLOW_COPY_AND_ASSIGN (SocketClient)

Private Member Functions inherited from Atomic
void	lock ()

void	unlock ()

Static Private Member Functions
static bool	local_test (struct addrinfo *addr)
	Test if a given address is local.

Private Attributes
long long	startTime_
	When the last connection attempt was started.

StateFlowTimer	timer_ {this}
	Helper for sleeping.

std::unique_ptr< SocketClientParams >	params_
	Stores the parameter structure.

std::function< void(int, Notifiable *)>	callback_ = nullptr
	callback to call on connection success

ExecutorBase *	connectExecutor_ = nullptr
	Executor for synchronous (blocking) connect calls. Externally owned.

ExecutorBase *	mdnsExecutor_ = nullptr
	Executor for synchronous (blocking) mDNS lookup calls.

std::array< Attempt, 5 >	strategyConfig_
	Stores the sequence of operations we need to try.

uint8_t	strategyOffset_: 3
	What is the next step in the strategy.

uint8_t	mdnsPending_: 1
	true if there is a pending mdns lookup operation.

uint8_t	mdnsJoin_: 1
	true if the main flow is waiting for the mdns lookup to complete.

uint8_t	sleeping_: 1
	true while we are waiting for the timer.

uint8_t	requestShutdown_: 1
	true if an external agent requested the flow to exit.

uint8_t	isConnected_: 1
	true if we are connected and waiting for a client notification to restart.

AddrinfoPtr	mdnsAddr_
	Holds the results of the mdns lookup. null if failed (or never ran).

BarrierNotifiable	n_

int	fd_
	socket descriptor

Additional Inherited Members
Protected Types inherited from StateFlowBase
typedef Action(StateFlowBase::*	Callback) ()
	State Flow callback prototype.

Protected Member Functions inherited from StateFlowBase
	StateFlowBase (Service *service)
	Constructor.

	~StateFlowBase ()
	Destructor.

void	reset_flow (Callback c)
	Resets the flow to the specified state.

bool	is_state (Callback c)

bool	is_terminated ()

void	start_flow (Callback c)
	Resets the flow to the specified state and starts it.

Action	again ()
	Call the current state again via call_immediately.

Action	exit ()
	Terminate current StateFlow activity.

Action	delete_this ()
	Terminates the flow and deletes *this.

Action	set_terminated ()
	Sets the flow to terminated state.

Action	call_immediately (Callback c)
	Imediately call the next state upon return.

Action	wait ()
	Wait for an asynchronous call.

Action	wait_and_call (Callback c)
	Wait for resource to become available before proceeding to next state.

template<class T >
Action	allocate_and_call (FlowInterface< Buffer< T > > target_flow, Callback c, Pool pool=nullptr)
	Allocates a buffer from a pool and proceed to the next state when allocation is successful.

Action	allocate_and_call (Callback c, QAsync *queue)
	Allocates an entry from an asynchronous queue, and transitions to a state once the allocation is complete.

template<class T >
Buffer< T > *	full_allocation_result (FlowInterface< Buffer< T > > *target_flow)
	Takes the result of the asynchronous allocation without resetting the object.

template<class T >
T *	full_allocation_result (TypedQAsync< T > *queue)
	Takes the result of the asynchronous allocation without resetting the object.

template<class T >
void	cast_allocation_result (T **member)
	Takes the result of the asynchronous allocation without resetting the object.

template<class T >
Buffer< T > *	get_allocation_result (FlowInterface< Buffer< T > > *target_flow)
	Takes the result of the asynchronous allocation.

Action	yield_and_call (Callback c)
	Place the current flow to the back of the executor, and transition to a new state after we get the CPU again.

Action	yield ()
	Place the current flow to the back of the executor, and re-try the current state after we get the CPU again.

Action	sleep_and_call (::Timer *timer, long long timeout_nsec, Callback c)
	Suspends execution of this control flow for a specified time.

template<class T , typename... Args>
Action	invoke_subflow_and_wait (FlowInterface< Buffer< T > > *target_flow, Callback c, Args &&... args)
	Calls a helper flow to perform some actions.

Action	read_repeated (StateFlowSelectHelper helper, int fd, void buf, size_t size, Callback c, unsigned priority=Selectable::MAX_PRIO)
	Blocks until size bytes are read and then invokes the next state.

Action	read_single (StateFlowSelectHelper helper, int fd, void buf, size_t size, Callback c, unsigned priority=Selectable::MAX_PRIO)
	Attempts to read at most size_t bytes, and blocks the caller until at least one byte is read.

Action	read_nonblocking (StateFlowSelectHelper helper, int fd, void buf, size_t size, Callback c, unsigned priority=Selectable::MAX_PRIO)
	Attempts to read at most size bytes, and then invokes the next state, even if only zero bytes are available right now.

Action	read_repeated_with_timeout (StateFlowTimedSelectHelper helper, long long timeout_nsec, int fd, void buf, size_t size, Callback c, unsigned priority=Selectable::MAX_PRIO)
	Blocks until size bytes are read, or a timeout expires.

Action	internal_try_read ()
	Implementation state that gets repeatedly called upon every wakeup and tries to make progress on reading.

Action	write_repeated (StateFlowSelectHelper helper, int fd, const void buf, size_t size, Callback c, unsigned priority=Selectable::MAX_PRIO)
	Writes some data into a file descriptor, repeating the operation as necessary until all bytes are written.

Action	internal_try_write ()
	Implementation state that gets repeatedly called upon every wakeup and tries to make progress on writing.

Protected Member Functions inherited from QMember
	QMember ()
	Constructor.

	~QMember ()
	Destructor.

Protected Attributes inherited from QMember
QMember *	next
	pointer to the next member in the queue

Detailed Description

Definition at line 56 of file SocketClient.hxx.

Member Typedef Documentation

◆ AddrinfoPtr

typedef std::unique_ptr<struct addrinfo, AddrInfoDeleter> SocketClient::AddrinfoPtr

Custom unique pointer that knows how to delete a struct addrinfo.

Definition at line 119 of file SocketClient.hxx.

Member Enumeration Documentation

◆ Attempt

enum class SocketClient::Attempt : uint8_t

strong

This enum represents individual states of this state flow that we can branch to.

The configuration of connection strategy is a sequence of these enum values.

Enumerator
RECONNECT	Connect to the reconnect slot.
INITIATE_MDNS	Start mDNS lookup.
CONNECT_MDNS	Connect to mDNS lookup result.
CONNECT_STATIC	Connect to static target.
WAIT_RETRY	Attempt complete. Start again.
FAILED_EXIT	Failed and do not start again (for one-shot mode).

Definition at line 124 of file SocketClient.hxx.

Constructor & Destructor Documentation

◆ SocketClient()

SocketClient::SocketClient	(	Service *	service,
		ExecutorBase *	connect_executor,
		ExecutorBase *	mdns_executor,
		std::unique_ptr< SocketClientParams >	params,
		std::function< void(int, Notifiable *)>	connect_callback
	)

inline

Constructor.

Parameters

service	service that the StateFlowBase will be bound to. This service will never be blocked. Externally owned.
connect_executor	is a thread on which DNS lookups and blocking connect calls will be attempted. Externally owned. May be shared between different SocketClients.
mdns_executor	is a thread on which mdns lookups will be attempted. May be null if mdns is never used (by the parameters) or may be the same executor as connect_executor if connect and mdns attempts ought to be serialized. Externally owned. May be shared between different SocketClients.
params	defines all the different parameters on whom to connect to. Takes ownership.
connect_callback	callback method to invoke when a client connection is made successfully. It is unspecified which thread this callback will be invoked upon. First param is the file descriptor of the resulting socket Second param is a notifiable (ownership is not transferred). The callee must invoke this notifiable when the socket has been torn down in order to restart the search with the same parameters.

Definition at line 80 of file SocketClient.hxx.

◆ ~SocketClient()

SocketClient::~SocketClient ( )

inline

Destructor.

Definition at line 101 of file SocketClient.hxx.

Member Function Documentation

◆ address_to_string()

static bool SocketClient::address_to_string	(	struct addrinfo *	addr,
		string *	host,
		int *	port
	)

static

Converts a struct addrinfo to a dotted-decimal notation IP address.

Parameters

addr	is an addrinfo returned by getaddrinfo or gethostbyname.
host	will be filled with dotted-decimal IP address.
port	will be filled with the port number.

Returns: true on success.

◆ connect() [1/3]

static int SocketClient::connect	(	const char *	host,
		const char *	port_str
	)

static

Connects a tcp socket to the specified remote host:port.

Returns -1 if unsuccessful; returns the fd if successful.

Parameters

host	hostname to connect to. Shall be null for mDNS target.
port_str	TCP port number or mDNS hostname to connect to.

Returns: fd of the connected socket.

◆ connect() [2/3]

static int SocketClient::connect	(	const char *	host,
		int	port
	)

inlinestatic

Connects a tcp socket to the specified remote host:port.

Returns -1 if unsuccessful; returns the fd if successful.

Parameters

host	hostname to connect to
port	TCP port number to connect to

Returns: fd of the connected socket.

Definition at line 227 of file SocketClient.hxx.

◆ connect() [3/3]

static int SocketClient::connect ( struct addrinfo * addr )

static

Connects a tcp socket to the specified remote address.

Returns -1 if unsuccessful; returns the fd if successful.

Parameters

addr	IP(v4/v6) addrinfo structure describing the remote host. May be null. Ownership is not transferred. Will not be used after the funciton returns.

Returns: fd of the connected socket.

◆ connect_blocking()

void SocketClient::connect_blocking	(	const string &	host,
		int	port
	)

inlineprivate

Called on the connect executor.

Parameters

host	hostname (or IP address in text form) to connect to
port	port number to connect to.

Definition at line 417 of file SocketClient.hxx.

◆ connect_complete()

Action SocketClient::connect_complete ( )

inlineprivate

State that gets invoked once the reconnect attempt is complete.

Definition at line 434 of file SocketClient.hxx.

◆ connect_mdns()

Action SocketClient::connect_mdns ( )

inlineprivate

Takes the address from the mdns lookup and connects to it if it is valid.

Returns: next step or pending connection step.

Definition at line 556 of file SocketClient.hxx.

◆ connected()

Action SocketClient::connected ( )

inlineprivate

State that gets called when we have a completed connection in fd_.

Definition at line 449 of file SocketClient.hxx.

◆ failed_oneshot()

Action SocketClient::failed_oneshot ( )

inlineprivate

Last state in the connection sequence, when everything failed, but the caller wanted one shot only.

Definition at line 572 of file SocketClient.hxx.

◆ is_connected()

bool SocketClient::is_connected ( )

inline

Returns: true if we have a working connection.

Definition at line 175 of file SocketClient.hxx.

◆ is_shutdown()

bool SocketClient::is_shutdown ( )

inline

Returns: true if the shutdown has completed.

Definition at line 182 of file SocketClient.hxx.

◆ local_test()

static bool SocketClient::local_test ( struct addrinfo * addr )

staticprivate

Test if a given address is local.

Parameters

addr	address info to test

Returns: true if local, else false if not local

◆ mdns_lookup()

void SocketClient::mdns_lookup	(	string	mdns_hostname,
		string	mdns_service
	)

inlineprivate

Synchronous function that runs on the mdns executor.

Performs the lookup.

Parameters

mdns_service	is the service name to look up.
mdns_hostname	is ignored for now.

Definition at line 501 of file SocketClient.hxx.

◆ next_step()

Action SocketClient::next_step ( )

inlineprivate

Execute the next step of the strategy.

Definition at line 353 of file SocketClient.hxx.

◆ prepare_strategy()

void SocketClient::prepare_strategy ( )

inlineprivate

Parses the params_ configuration and fills in strategyConfig_.

Definition at line 280 of file SocketClient.hxx.

◆ reset_params()

void SocketClient::reset_params ( std::unique_ptr< SocketClientParams > params )

inline

Updates the parameter structure for this socket client.

Parameters

params is the parameter structure; ownership will be transferred.

Todo:: (balazs.racz): do we need to somehow wake up the flow and make it attempt to reconnect?

Definition at line 143 of file SocketClient.hxx.

◆ shutdown()

void SocketClient::shutdown ( )

inline

Shutdown the client so that it can be deleted.

Definition at line 152 of file SocketClient.hxx.

◆ sleep_done()

Action SocketClient::sleep_done ( )

inlineprivate

Definition at line 595 of file SocketClient.hxx.

◆ start_connection()

Action SocketClient::start_connection ( )

inlineprivate

Main entry point of the connection process.

Definition at line 337 of file SocketClient.hxx.

◆ start_mdns()

Action SocketClient::start_mdns ( )

inlineprivate

State that initiates the mdns lookup asynchronously.

Returns: next step state.

Definition at line 479 of file SocketClient.hxx.

◆ start_shutdown()

void SocketClient::start_shutdown ( )

inline

Request that this client shutdown and exit the other thread.

Definition at line 189 of file SocketClient.hxx.

◆ string_to_address() [1/2]

static AddrinfoPtr SocketClient::string_to_address	(	const char *	host,
		const char *	port_str
	)

static

Converts a hostname string (or null) and port number (or service name) to a struct addrinfo.

Parameters

host	hostname to connect to.
port	port name or service name to connect to.

Returns: a struct addrinfo; ownership is transferred to the caller.

◆ string_to_address() [2/2]

static AddrinfoPtr SocketClient::string_to_address	(	const char *	host,
		int	port
	)

inlinestatic

Converts a hostname string and port number to a struct addrinfo.

Parameters

host	hostname to connect to.
port	port number to connect to.

Returns: a struct addrinfo; ownership is transferred.

Definition at line 265 of file SocketClient.hxx.

◆ to_string()

string SocketClient::to_string ( const char * p )

inlineprivate

Turns a parameter to a string.

Parameters

p	is a parameter; may be nullptr or empty.

Returns: empty string if p is null or empty, otherwise p (copied).

Definition at line 468 of file SocketClient.hxx.

◆ try_schedule_connect()

Action SocketClient::try_schedule_connect	(	SocketClientParams::LogMessage	log,
		string	host,
		int	port
	)

inlineprivate

Helper function to schedule asynchronous connect on a separate executor.

Never blocks. Will deliver exactly one notify to the barrier notifiable n_.

Parameters

log	will be emitted to the params_ structure if connection is attempted.
host	hostname (or IP address in text form) to connect to. May be empty in which case no connection will be attempted.
port	port number to connect to.

Returns: the connection wait action or next_state depending on whether connection was attempted.

Definition at line 396 of file SocketClient.hxx.

◆ wait_and_connect_mdns()

Action SocketClient::wait_and_connect_mdns ( )

inlineprivate

Blocks the flow until mdns lookup is complete, then connects to the resulting address.

Returns: mdns connect step

Definition at line 540 of file SocketClient.hxx.

◆ wait_retry()

Action SocketClient::wait_retry ( )

inlineprivate

Last state in the connection sequence, when everything failed: sleeps until the timeout specified in the params, then goes back to the start_connection.

Definition at line 580 of file SocketClient.hxx.

Member Data Documentation

◆ callback_

std::function<void(int, Notifiable *)> SocketClient::callback_ = nullptr

private

callback to call on connection success

Definition at line 619 of file SocketClient.hxx.

◆ connectExecutor_

ExecutorBase* SocketClient::connectExecutor_ = nullptr

private

Executor for synchronous (blocking) connect calls. Externally owned.

Definition at line 622 of file SocketClient.hxx.

◆ fd_

int SocketClient::fd_

private

socket descriptor

Definition at line 659 of file SocketClient.hxx.

◆ isConnected_

uint8_t SocketClient::isConnected_

private

true if we are connected and waiting for a client notification to restart.

Definition at line 651 of file SocketClient.hxx.

◆ mdnsAddr_

AddrinfoPtr SocketClient::mdnsAddr_

private

Holds the results of the mdns lookup. null if failed (or never ran).

Definition at line 654 of file SocketClient.hxx.

◆ mdnsExecutor_

ExecutorBase* SocketClient::mdnsExecutor_ = nullptr

private

Executor for synchronous (blocking) mDNS lookup calls.

Externally owned, may be null.

Definition at line 625 of file SocketClient.hxx.

◆ mdnsJoin_

uint8_t SocketClient::mdnsJoin_

private

true if the main flow is waiting for the mdns lookup to complete.

Guarded by Atomic *this.

Definition at line 641 of file SocketClient.hxx.

◆ mdnsPending_

uint8_t SocketClient::mdnsPending_

private

true if there is a pending mdns lookup operation.

Guarded by Atomic *this.

Definition at line 637 of file SocketClient.hxx.

◆ n_

BarrierNotifiable SocketClient::n_

private

Definition at line 656 of file SocketClient.hxx.

◆ params_

std::unique_ptr<SocketClientParams> SocketClient::params_

private

Stores the parameter structure.

Definition at line 616 of file SocketClient.hxx.

◆ requestShutdown_

uint8_t SocketClient::requestShutdown_

private

true if an external agent requested the flow to exit.

Definition at line 647 of file SocketClient.hxx.

◆ sleeping_

uint8_t SocketClient::sleeping_

private

true while we are waiting for the timer.

Definition at line 644 of file SocketClient.hxx.

◆ startTime_

long long SocketClient::startTime_

private

When the last connection attempt was started.

Definition at line 611 of file SocketClient.hxx.

◆ strategyConfig_

std::array<Attempt, 5> SocketClient::strategyConfig_

private

Initial value:

{{
        Attempt::WAIT_RETRY,
    }}

Stores the sequence of operations we need to try.

Definition at line 628 of file SocketClient.hxx.

◆ strategyOffset_

uint8_t SocketClient::strategyOffset_

private

What is the next step in the strategy.

Index into the strategyConfig_ array. Guarded by Atomic *this.

Definition at line 633 of file SocketClient.hxx.

◆ timer_

StateFlowTimer SocketClient::timer_ {this}

private

Helper for sleeping.

Definition at line 613 of file SocketClient.hxx.

The documentation for this class was generated from the following file:

SocketClient.hxx

Classes

Public Types

Public Member Functions

Static Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ AddrinfoPtr

Member Enumeration Documentation

◆ Attempt

Constructor & Destructor Documentation

◆ SocketClient()

◆ ~SocketClient()

Member Function Documentation

◆ address_to_string()

◆ connect() [1/3]

◆ connect() [2/3]

◆ connect() [3/3]

◆ connect_blocking()

◆ connect_complete()

◆ connect_mdns()

◆ connected()

◆ failed_oneshot()

◆ is_connected()

◆ is_shutdown()

◆ local_test()

◆ mdns_lookup()

◆ next_step()

◆ prepare_strategy()

◆ reset_params()

◆ shutdown()

◆ sleep_done()

◆ start_connection()

◆ start_mdns()

◆ start_shutdown()

◆ string_to_address() [1/2]

◆ string_to_address() [2/2]

◆ to_string()

◆ try_schedule_connect()

◆ wait_and_connect_mdns()

◆ wait_retry()

Member Data Documentation

◆ callback_

◆ connectExecutor_

◆ fd_

◆ isConnected_

◆ mdnsAddr_

◆ mdnsExecutor_

◆ mdnsJoin_

◆ mdnsPending_

◆ n_

◆ params_

◆ requestShutdown_

◆ sleeping_

◆ startTime_

◆ strategyConfig_

◆ strategyOffset_

◆ timer_