Firebug 1.8: Architecture Refactoring

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Firebug 1.7 got redirected to support Firefox 4.0 changes. Therefore Firebug 1.8 takes up the refactoring work.

Problems to be Solved by Refactoring[edit]

  • Prepare to support remote debugging for mobile and multiprocess browser
    • Server side will be headless
    • Client side will have no access to Firefox data
  • Allow simpler and more robust extensions
    • JavaScript oriented loading, no XPCOM loader required
    • Isolation and concentration of extension code
  • Clean up expedient code and clarify the implementation
    • relation to platform window system
    • relation of panels and modules
    • relation of panels to platform-specific UI integration

See also the Firebug 1.8 API Changes for more detailed info.


1.7 Lite XUL Monolithic Firebug on Firefox
1.8 BTI Lite XUL Front-ish BTI Back-ish
1.8 Multiprocess (jetpack) Lite+Front - BTI -Crossfire- BTI - Firefox Back
1.8 Fennec (jetpack) Lite+Front - BTI -Crossfire- BTI - Fennec Backend
1.8 Remote (jetpack) Lite+Front - BTI -Crossfire- BTI - Security Backend

Main Steps[edit]

Convert Firebug FBL.ns to require.js modules[edit]

To completely control the loading and scope of JS code we want to shift from script tags to require.js modules. We need to:

  1. Wrap our JS code in a different function: FBL.ns(function () {...}); -> define([deps], function() {....});
  2. Add a return statement
  3. deal with scope problems.
  4. separate files into Firebug.Modules files and Firebug.Panel files
  5. replace Cu.import modules with require.js modules

This work is on the modules branch.

We currently have about 5 modules working, all related to script.js Script panel.

References on modules:

Introduce Browser Tools Interface[edit]

Remote Firebug puts module code in the server and the panel code in the client (UI side). The two sides communicate over Crossfire.

This work is on the bti branch.

Issue: file names vs folders[edit]

Recode TabWatcher -> DOMWindowWatcher[edit]

I think we now pretty much understand TabWatcher, but it is still very heuristic and relies on Firefox idiosyncrasies that can change. Chromebug has its own watcher and even more guesses about the platform. Let's replace all of that with a clean abstraction for nsIXULWindow and nsIDOMWindow lifetime event notifications. Then put it in a SharedObject so we only need one per application and we have clearer API.

This requires platform support

Issue: DOMWindowWatcher API[edit]

Ideally we would mimic/influence jetpack here, as they have a subset of the same problem.

Sandboxed Extension Loading[edit]

By re-applying the module loading technology we can create a jetpack-like environmental wrapper for Firebug extensions. The extensions would be slightly simpler because they would just be zip files. They would be slightly more robust, because they would be evaled in a scope that only contains Firebug.

Refactor debugger.js <-> firebug-service.js API[edit]

Ultimately we want debugger.js to split into a front-end and back-end, with the back-end implementing Crossfire's V8-like protocol. So a start is to shift work between debugger.js and firebug-service.js to be an V8-like API, and use firebug-service.js as an adapter between V8-like protocol and Mozilla jsd. (Note that JSDebugv2 aka js::dbg should have this kind of API).

Detailed Work Plan For JS Reimplementation[edit]

Please ask jjb about any code in debugger.js or firebug-service.js that involves 'jsd' or 'fbs'. This code is all going away and we don't want to invest your time in understanding it more than needed.

  1. Milestone BTI: Interface, Unit Tests, firebug-service encapsulation
    1. Preliminary: move mozilla-specific code from debugger.js to fbs, split out script.js (front end).
    2. Define (initial) BrowserToolsInterface (BTI)
    3. Create unit tests for BTI
    4. Implement BTI with mozilla-backend.js based on firebug-service.js
      • This will only last for FF4.1, it can be a hack job.
  2. Milestone Script.js: Firebug Lite script.js implemented with Firebug/Firefox sourcebox panel
    1. port sourcebox panel to Lite
    2. build new script panel based on sourcebox panel
  3. Milestone Script/BTI: in process use of BTI in Firefox
    1. Insert BTI into script.js, calls mozilla-backend.js
      • FBTests pass, the result will be first ship of BTI This is the proposed 1.8 target for 2011.
  4. Milestone CrossUnit: Unit tests via CrossFire
    1. Implement Crossfire server to BTI calls
    2. Implement Crossfire client from BTI calls
    3. Drive unit tests end to end
  5. Milestone Crossfox: Crossfire from Firefox to Firefox
    1. script.js to BTI to CrossFire Client to Server to mozilla-backend.js
    2. FBTest pass
    3. Fennec prototype
    • the result will be first user value add and prepared for jsdv2
  6. Milestone Modularity: script.js usable in Firebug Lite and Firefox
    1. Preliminary: modularity model.
    2. script.js in Firebug Lite -> Firefox mozilla-backend.js
  7. Milestone ChromeUnit: Crossfire into V8
    1. Implement V8 server (or not to start).
    2. Drive unit tests into Chrome / V8
  8. Milestone ChromeScript: Firebug Lite JS debug in Chrome
    1. Firebug Lite script.js drives Chrome/V8
    • Result will be user value add Chrome JS debug with Firebug.

How to participate[edit]