Selectable Class Reference

#include <Pt/System/Selectable.h>

Operation that runs through an event loop. More...

Inherits NonCopyable.

Inherited by Script, TcpServer, AsyncYield [private], IODevice, and IONotifier.

Public Member Functions
virtual	~Selectable ()
	Destructor.
void	setActive (EventLoop &parent)
	Sets the parent loop, so that operations can be run.
void	detach ()
	Remove from event loop and cancels outstanding operations.
void	cancel ()
	Cancels all operations.
bool	run ()
	Run operation if it is ready.
EventLoop *	parent () const
	Returns the used event loop.

Protected Member Functions
	Selectable ()
	Default Constructor.
void	post ()
	Posts this selectable to its event loop from any thread.
virtual void	onAttach (EventLoop &)
	Attached to loop.
virtual void	onDetach (EventLoop &)
	Detached from loop.
virtual void	onCancel ()=0
	Blocks until operation has cancelled.
virtual bool	onRun ()=0
	Check if ready and run.

Detailed Description

Selectable is the attachment between an asynchronous operation and an EventLoop. setActive() attaches it. The loop then monitors the operation. detach() removes it and cancels work that is still running. cancel() cancels without detaching. parent() is the loop.

run() executes the operation when the loop has marked it ready. post() asks the loop to run it from any thread. IODevice and IONotifier are selectables. Timer is not; it registers with the loop on its own.

The loop does not own the selectable. The caller keeps it alive while it is attached.