User:Alive/System Refactor Plan

System Refactor Plan

High level goals

• Modularization
  • Concentrated module responsibility
• One system app for multiple devices
  • Swappable functionality
  • One business logic, different UI logic
• Maintenance
  • Code readability
  • Test coverage
• Performance
  • Reduce startup time

Multiple device support

• Hardware feature detector - done in Core
• In the long term, we will have all what we need in the code base
  • Package device specific modules in build time
  • Load/start modules correspondingly in run time

Swappable functionality

• Each HW specific functionality should be easily removed/disabled from the current code base.
• Less module dependency - try not touch global variable.

If you need to ask someone else to work, ask the mediator instead of asking it directly.

 var MyModule = {
   show: function() {
     UtilityTray.hide(); // Sad
     Service.request('UtilityTray:hide'); // Better
   }
 };

Concentrated Module Responsibility

• A module is always used to accomplish a specific task
• If an module has too many tasks to do - stop and think about it
  • What's the core task of this module?
  • Could we use a shared logic between modules?
  • Could we have a submodule to help on certain tasks?

Performance

Tracking bug: bug 1094768

• Setup dependency tree

 Launcher -> Core -> Subsystem Launcher -> ...

• Determine the critical launch path: Lockscreen, FTU or Homescreen
• Lazy load non-critial modules by the tree order

Special Topics

• AppWindowManager dismantling
• Statusbar dismantling
• Shared transition controller
• Notification refactor
• LockScreen
• SystemDialog

AppWindowManager dismantling

• AppWindowManager is still heavy now.
• Current direction is to look into TV's AWM requirements and see how we could split it.
• Idea: shared WindowManager interface + shared app switch interface.
  • We have many WindowManager right now, maybe we should have a baseWindowManager
  • Window switch feature is complex and it is phone(Single window device) specific.

Statusbar dismantling

• Icon operation is already dismantled in bug 1098168
• Todo: Instantiation, take UtilityTray as submodule

Notification Refactor

• Ideally we shall have a simple NotificationManager singleton and several NotificationUI instances
• NotificationManager is responsible to create NotificationUI instances due to events from gecko
• The behavior of the NotificationUI is dependent from the NotificationManager
• NotificationUI is device specific - it may change due to UX design

LockScreen

Tracking Bug:

• LockScreen is going to be a new app at certain timing. However we should make it less dependent from other modules in the system before that really happens

 Core -> AppCore -> LockScreenWindowManager -> LockScreenWindow -> (LockScreenLoader) -> LockScreen specific modules

System Dialog-lize

Tracking Bug:

• All non appWindow specific dialog should be refactored into SystemDialog and managed by SystemDialogManager
  • CustomDialog/ModalDialog/AppInstallDialog/UpdateDialog/...
• AppInstallDialog: bug 1111975 Pending