2000235 - Use string pattern matching instead of regex to implement MatchGlob

Status: ASSIGNED

(WebExtensions :: General, enhancement)

Description

[Jeff Muizelaar [:jrmuizel]]

This avoids the cost having to compile the regular expressions during startup and I expect the matching will be a similar speed for most expressions. In any case, actual match speed shouldn't be too much of a bottleneck because we match on domains first and it will be no slower than Chrome.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

Attachment: Bug 2000235. Port MatchPattern from Chromium to xpcom/string.

This takes the code from base/strings/pattern* at revision
0c26a6fd68e146fc98becc4b69e8c2e8cdcc0ea6 and makes
it operate on nsStrings.

Like in Chromium it will be used to implement webRequest
match patterns.

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Attachment: Bug 2000235. Switch from RustRegex to MatchPattern.

This avoids the cost having to compile the regular expressions during startup
and I expect the matching will be a similar speed for most expressions. In any
case, actual match speed shouldn't be too much of a bottleneck because we match
on domains first and it will be no slower than Chrome.

We spend 22ms compiling regexes during Fenix startup so this should
help there:
https://share.firefox.dev/4qXikKP

Comment 3

[Jeff Muizelaar [:jrmuizel]]

Attachment: Bug 2000235. Drop special casing of easy patterns.

The new MatchPattern code shouldn't be much slower than the fast path and this
keeps things simpler. It also matches what Chromium does.

Comment 4

[Jeff Muizelaar [:jrmuizel]]

I also have a Rust version of the string pattern matching if there's a preference for that: https://github.com/jrmuizel/chromium-string-pattern/blob/main/src/lib.rs