NAME

Sys::Virt::Event - An event loop contract

DESCRIPTION

The "Sys::Virt::Event" module represents the contract for integrating libvirt with an event loop. This package is abstract and intended to be subclassed to provide an actual implementation.

METHODS

register_default(): Register the default libvirt event loop implementation
run_default(): Run a single iteration of the default event loop implementation
register($impl): Register an event loop implementation. The implementation should be a instance of a sub-class of the "Sys::Virt::Event" package.
$self->_run_handle_callback($watch, $fd, $events, $cb, $opaque): A helper method for executing a callback in response to one of more $events on the file handle $fd. The $watch number is the unique idenifier associated with the file descriptor. The $cb and $opaque parameters are the callback and data registered for the handle.
$self->_run_timeout_callback($timer, $cb, $opaque): A helper method for executing a callback in response to the expiry of a timeout identified by $timer. The $cb and $opaque parameters are the callback and data registered for the timeout.
$self->_free_callback_opaque($ff, $opaque): A helper method for freeing the data associated with a callback. The $ff and $opaque parameters are the callback and data registered for the handle/timeout.
my $watch = Sys::Virt::Event::add_handle($fd, $events, $coderef): Adds a watch on the file descriptor $fd for the events $events which is a mask of the FILE HANDLE EVENTS constants listed later. The $coderef parameter is a subroutine to invoke when an event is triggered. The subroutine will be passed three parameters, the watch identifier, the file descriptor and the event mask. This method returns the watch identifier which can be used to update or remove the watch
Sys::Virt::Event::update_handle($watch, $events): Update the event mask for the file descriptor watch $watch to use the events $events.
Sys::Virt::Event::remove_handle($watch): Remove the event mask for the file descriptor watch $watch.
my $watch = Sys::Virt::Event::add_timeout($frequency, $coderef): Adds a timeout to trigger with $frequency milliseconds interval. The $coderef parameter is a subroutine to invoke when an event is triggered. The subroutine will be passed one parameter, the timer identifier. This method returns the watch identifier which can be used to update or remove the watch
Sys::Virt::Event::update_timeout($timer, $frequency): Update the timeout $timer to have the frequency $frequency milliseconds.
Sys::Virt::Event::remove_timeout($timer): Remove the timeout $timer

CONSTANTS

FILE HANDLE EVENTS

When integrating with an event loop the following constants define the file descriptor events

Sys::Virt::Event::HANDLE_READABLE: The file descriptor has data available for read without blocking
Sys::Virt::Event::HANDLE_WRITABLE: The file descriptor has ability to write data without blocking
Sys::Virt::Event::HANDLE_ERROR: An error occurred on the file descriptor
Sys::Virt::Event::HANDLE_HANGUP: The remote end of the file descriptor closed

AUTHORS

Daniel P. Berrange <berrange@redhat.com>

COPYRIGHT

LICENSE

This program is free software; you can redistribute it and/or modify it under the terms of either the GNU General Public License as published by the Free Software Foundation (either version 2 of the License, or at your option any later version), or, the Artistic License, as specified in the Perl README file.