Open Bug 1743749 Opened 2 years ago Updated 1 year ago

Clean up use of atoms for cache keys


(Core :: Disability Access APIs, task)





(Reporter: Jamie, Unassigned)


(Blocks 1 open bug)


We use AccAttributes for the CTW cache and AccAttributes is keyed by nsAtom. This has some advantages as compared to an enum: we don't need separate data structures for object/text attributes and the CTW cache and we get readable logging for the keys for free. However, a major disadvantage is that because we try to avoid polluting the nsGkAtoms namespace, we end up with some unclear/unintuitive keys; e.g. nsGkAtoms::line for text line start boundaries, nsGkAtoms::style for text attributes, etc.

We need to find a way to make this more obvious and readable. We can either alias the atoms in our own namespace or switch to using an enum after all.

I looked into various approaches of aliasing. We can't use an enum because enums have to be convertable to int. We can't use a using declaration because they only work for types, not values. What does work is this:

class CacheKey {
  static constexpr nsStaticAtom* TextLineStarts = nsGkAtoms::line;
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