1895462 - Allow WeakCache containers to use UniquePtrs

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task, P2)

Description

[Jon Coppeard (:jonco)]

While working on bug 1894012 I wanted to add a WeakCached map where the keys were UniquePtrs and was surprised this wasn't possible.

It turns out that our incremental sweeping for maps and sets calls the copy constructors of keys and values and that doesn't work with something like UniquePtr where the copy constructor is deleted.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1895462 - Allow UniquePtrs to be used in WeakCache hash maps r?sfink

The problem here is that we copy the keys/values in entryNeedsSweep. I tried
several strategies to avoid this but in the end the simplest thing to do was
add a needsSweep method to the GC policy templates that calls
IsAboutToBeFinalized. I've implemented this only where necessary (and WeakCache
is only used internally nowadays).

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/bb3c347722e6
Allow UniquePtrs to be used in WeakCache hash maps r=sfink

Comment 3

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/bb3c347722e6