waitset.h File Reference

Waitset and low-level event handling mechanism. More...

Data Structures
struct	waitset_chanstate
	Per-channel state belonging to waitset. More...
struct	waitset
	Wait set. More...

Enumerations

Functions
void	poll_channels_disabled (dispatcher_handle_t handle)
	Check polled channels.
void	waitset_init (struct waitset *ws)
	Initialise a new waitset.
errval_t	waitset_destroy (struct waitset *ws)
	Destroy a previously initialised waitset.
errval_t	get_next_event (struct waitset *ws, struct event_closure *retclosure)
	Wait for (block) and return next event on given waitset. More...
errval_t	get_next_event_disabled (struct waitset *ws, struct waitset_chanstate **retchan, struct event_closure *retclosure, struct waitset_chanstate *waitfor, struct waitset_chanstate *waitfor2, dispatcher_handle_t handle, bool debug)
	Get next pending event. More...
errval_t	event_dispatch (struct waitset *ws)
	Wait for (block) and dispatch next event on given waitset. More...
errval_t	wait_for_channel (struct waitset *ws, struct waitset_chanstate *channel, errval_t *error_var)
	Dispatch events until a specific event is received. More...
errval_t	event_dispatch_non_block (struct waitset *ws)
	check and dispatch next event on given waitset More...

Detailed Description

Waitset and low-level event handling mechanism.

Enumeration Type Documentation

enum ws_chanstate

Current state of a channel on a specific waitset.

Enumerator
CHAN_UNREGISTERED	Initialised, but not yet registered on a waitset.
CHAN_IDLE	Has a registered event handler, but the event has not fired.
CHAN_POLLED	Idle and polled. Channel implementation must be called to check for pending events.
CHAN_PENDING	Has a pending event waiting to be delivered.
CHAN_WAITING	There's no registered event handler (for now)

enum ws_chantype

Channel type.

This is used for debugging and to determine the function to call when polling.

Enumerator
CHANTYPE_DEFERRED	Timer events.

Function Documentation

errval_t event_dispatch

(

struct waitset *

ws

)

Wait for (block) and dispatch next event on given waitset.

Wait until something happens, either activity on some channel, or deferred call, and then call the corresponding closure.

Parameters

ws

Waitset

errval_t event_dispatch_non_block

(

struct waitset *

ws

)

check and dispatch next event on given waitset

Check if there is any pending activity on some channel, or deferred call, and then call the corresponding closure.

Do not wait! In case of no pending events, return err LIB_ERR_NO_EVENT.

Parameters

ws

Waitset

errval_t get_next_event	(	struct waitset *	ws,
		struct event_closure *	retclosure
	)

Wait for (block) and return next event on given waitset.

Wait until something happens, either activity on some channel, or a deferred call, and then return the corresponding closure. This is the core of the event-handling system.

Parameters

ws	Waitset
retclosure	Pointer to storage space for returned event closure

errval_t get_next_event_disabled	(	struct waitset *	ws,
		struct waitset_chanstate **	retchannel,
		struct event_closure *	retclosure,
		struct waitset_chanstate *	waitfor,
		struct waitset_chanstate *	waitfor2,
		dispatcher_handle_t	handle,
		bool	debug
	)

Get next pending event.

Check if there is a pending event that matches current thread and return it. Pending events are in a pending queue and in a waiting queue. A pending event then will be removed from a pending/waiting queue and become unregistered or, if it's persistent, will be re-registered to an idle queue or a polled queue (UMP channels) of a waitset. If there's no pending event, block this thread. If there's a pending event but it doesn't match our thread, don't remove it from a pending queue and wake up a matching thread. If there's no matching thread, add it to a waiting queue.

Parameters

ws	Waitset with sources of events
retchannel	Holder of returned event
retclosure	Holder of returned closure
waitfor	Specific event that we're waiting for (can be NULL)
handle	Dispatcher's handle
debug	Debug mode (not used)

errval_t wait_for_channel	(	struct waitset *	ws,
		struct waitset_chanstate *	waitfor,
		errval_t *	error_var
	)

Dispatch events until a specific event is received.

Wait for events and dispatch them. If a specific event comes, don't call a closure, just return.

Parameters

ws	Waitset
waitfor	Event, that we are waiting for
error_var	Error variable that can be changed by closures