Wednesday, October 10, 2007

Extension Development, and Trials and Tribulations Thereof

Well, I am almost done with an extension I am developing for a third-party company. Wow! Was this ever harder than I thought it would be....

I had some slightly complicated things in the extension. 2.5K lines of javascript, a custom XPCOM component, a status bar icon, a toolbar popup button, a sidebar, and a partridge in a pear tree thrown in for good measure. The app was crashing on exit. Actually only FF 2.* was crashing. FF 3.* was fine.

So, I am doing a bunch of different kinds of allocations and there are listeners and so on. I figured I was doing something wrong with the memory. Much staring at the code. Much re-reading of dbaron's docs on this stuff. Much more staring at code....

Turned out it was this:

<toolbarbutton id="id1" type="menu" popup="id2">
<menupopup id="id2" />

I thought that all this memory stuff might have a problem, and it turns out to be something bone simple! It is amazing what taking a machete to your code can show you. Along the way, an amusing thing happened. I took the image attribute off the toolbarbutton and I got this:

And someone said this was ok! I might try to guess at the logic, but I cannot make myself do it. Obviously, some people are very immersed in how XUL gets rendered. I hope I can learn enough to understand it. I hope I never forget that its contortions are, after all, contortions.

Next things to do now that this monkey is almost off my back:

- do an extension for rule-based qualification of XUL, because you need something to tell you that you can have A, B, and C together, but C makes B have no effect, and C without A does something totally different. Look at a given XUL reference. It inherits all its parent's attributes. Now, how many have any effect? How many break everything? There has got to be a way to get information about this.

- figure out something to help me search bugzilla. I looked for bugs on this many times and did not find it. Maybe it is because the relevant bug was marked for Windows. Maybe it was because the title mentioned <menupopup> and not <toolbarbutton>. Maybe it was because the title said it happened on window close and I was searching for "quit". I do not know. I just know I truly hate trying to find things in bugzilla. But when I suggest changes to bugzilla, they seem to hate that even more. I have no idea why. So, I just obviously need to construct tools to help me get around this thing. There has got to be a better way to find bugs than creating new bugs and letting gavin find the dupes. For one thing, this is not fair to gavin, or neil, or reed, or whoever it is.

- and some other things I am sure I have forgotten. We'll see.