927034 - Use defineLazyPrototypeGetter where possible

Status: RESOLVED INVALID

(DevTools :: General, defect)

Description

[Brandon Benvie [:benvie]]

It is pretty common to the find the pattern of a getter on a prototype that does something like:

> get property() {
>   if (this._property === null) {
>     this._property = someCreatorFunction();
>   }
>   return this._property;
> }

Bug 926725 introduces "defineLazyPrototypeGetter" which encapsulates this pattern and does it in a more optimized way (rough testing shows ~140x speed improvements on subsequent property accesses). We should replace the these existing manualy lazy getters with this new function.

Victor mentions Item class and WidgetMethods widget setter method in ViewHelpers.jsm as a start and I'm sure we use this elsewhere.

Comment 1

[Brandon Benvie [:benvie]]

This is also useful in places where we're calling `XPCOMUtils.defineLazyGetter` in a constructor. Using defineLazyPrototypeGetter in these cases is both more memory efficient and results in faster property accesses.

Comment 2

[Jan Honza Odvarko [:Honza] (always need-info? me)]

We are already doing it in DevTools code base.

Honza