1892936 - Storage caches are not stored in the local cache directory

Status: RESOLVED DUPLICATE of bug 1395705

(Core :: Storage: Cache API, enhancement)

Description

[:gerard-majax]

We can find cache within profile's storage, e.g., storage/default/https+++app.slack.com^userContextId=X/cache/ and it should probably rather be stored within $XDG_CACHE_DIR like provided if supported by GetUserDataDirectoryHome: https://searchfox.org/mozilla-central/rev/eb4700a6be8371fe07053bc066c2d48ba813ce3d/toolkit/xre/nsXREDirProvider.cpp#1221-1311

Comment 1

[Gian-Carlo Pascutto [:gcp]]

Similarly, on Windows this means the data is stored in the Roaming dir (which can often be over the network, especially in corporate installs) instead of in the Local Directory, which won't be, which could be giving us a serious performance disadvantage.

The GetUserDataDirectoryHome is also where all other caches are correctly stored.

This complicates/makes more annoying both XDG compliance (bug 259356) and will make profile backups (bug 1883052) much larger than needed.

Comment 2

[Andrew Sutherland [:asuth] (he/him)]

Cache API storage is not a cache but part of origin storage standardized under the storage spec which includes cookies. Duping to bug 1395705 where there's some discussion of whether we should effectively shard the user's origin state on a per-machine basis.

Profile backup in bug 1883052 I understand to specifically not involve origin content directories.