Subj : Re: Making a "Singleton" Chrome Extension
To   : Kyle
From : Brendan Eich
Date : Tue Jul 20 2004 09:12 am

Kyle wrote:
> I'm writing a chrome extension that currently creates an instance of
> an object when an overlay is loaded. This currently means that a new
> instance is created for every window that contains the overlay.
> 
> I would prefer to be able to create a single instance of the object
> when the Mozilla starts, and make reference to this instance when
> other windows are created. This also means that I would like to keep
> the instance alive after the overlay that created it has been
> destroyed.
> 
> This should just be a simple Singleton model. Is there some type of
> registry I can use to store and retrieve a reference to this object
> each time the overlay loads, and does anyone have any examples of a
> similar implementation? Thanks you,


You want to write an XPCOM component in JS, and call it via XPConnect. 
Many examples exist.  See 
http://lxr.mozilla.org/mozilla/source/xpcom/sample/nsSample.js, 
http://lxr.mozilla.org/mozilla/source/toolkit/mozapps/update/src/nsBackgroundUpdateService.js, 
http://lxr.mozilla.org/mozilla/source/toolkit/mozapps/extensions/src/nsExtensionManager.js.in, 
and others (http://lxr.mozilla.org/mozilla/search?string=createInstance%3A).

/be

.