Permissions for receiving messages

Hi,
The Permissions spec [1] does not allow any parameterization of permissions, and this does not appear necessary for the permissions it currently defines. However, for Messaging, I think it would be useful for "onSMS/onMMS/onEmail" to be able to limit what messages the widget/web app actually sees (in a sense similar to how WARP [2] spec limits network access for widgets).

A widget can filter out what messages it want to show/act on, however, I'm not really comfortable in allowing any widget to intercept ANY message as long as the widget has requested the right permission , which would be the case otherwise.

The current Permissions spec does not easily extend to this include this functionality as far as I can tell, thus an additional mechanism would be needed, perhaps something like WARP.

BTW, Android doesn't (as far as I can tell) allow this granularity.

Thoughts?

Best regards,
Niklas

[1] http://www.w3.org/TR/2010/WD-api-perms-20101005/
[2] http://www.w3.org/TR/2010/CR-widgets-access-20100420/