Application-focused Control

I love BAMF, may it die a peaceful death. BAMF was always stuck trying to solve an unsolvable problem, trying to recreate information and associations that had been lost through the X11 protocol and general fuzziness about what should happen. BAMF then had to handle a wide variety of corner cases and try to bring things back into a situation of sanity. And I loved BAMF because I didn't have to do that myself, BAMF did it, and all of its clients just got sanity. We knew when starting another display system we didn't want another BAMF.

With Mir there is a closer tie between applications as a whole and their windows. When an application asks for a session it specifies who it is, then Unity can make sure it understands who it is, and gets a chance to veto the connection. This means that Unity can check on the status of who the app says it is before it gets any windows and can track that directly throughout the application session. To do this we're using what we call the "Application ID", which for most apps you have today is the name of their desktop file (e.g., "inkscape", "gedit").

Let's look at an overly verbose message sequence diagram to see how this works. Note: all of the columns on here aren't separate processes, the diagram is made to explain this idea, not to represent the system architecture.


(svg | msc)

What we can see here is that because Upstart is doing process tracking, and making sure it knows the state of the application, Unity have have assurances of the application's name and existence. It then can work with Mir to block applications that do have proper configurations and can't be matched well. 100% matching, by design.

posted on Wed, 24 Jul 2013 at 11:55 | permanent link