It would be useful to be able to monitor the state of screensaver inhibition. xdg-screensaver provides the ability to find the current status, but that's only enough to write a polling implementation.

However, most modern desktops, using D-Bus, allow for a "push" implementation, where a client can listen for inhibition state changes.

It would be good to abstract this in xdg-screensaver.

Suggestion:

xdg-screensaver status-listen

starts a process that listens for changes to the status, and reports them on stdout. The parent can then take appropriate action.

Motivating case: I'd like to be able to add this function to caffeine-indicator (so that the indicator correctly indicates the status of the whole desktop, not just whether it is itself inhibiting the screensaver), without either inefficient polling that is not necessary, or reimplementation of code already mostly present in xdg-screensaver.