323821 - slowdown in about:config if filter term starts with *

Status: RESOLVED FIXED

(Toolkit :: Preferences, defect)

Description

[Simon Bünzli]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20060112 Firefox/1.5
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20060112 Firefox/1.5

Since the landing of the patch to bug 213832, filter strings starting with * unnecessarily slow down the whole browser. While it's easy to work around this problem (simply don't search for anything starting with *), the slowing down could still very cheaply be avoided - at least for all those who don't immediately get the new special meaning of *.

Reproducible: Always

Steps to Reproduce:
1. Open about:config
2. Filter for "*;false" (type slowly)

Actual Results:  
The browser hangs for several seconds.

Expected Results:  
No hanging.

Comment 1

[Simon Bünzli]

Attachment: ignore leading '*'s

Comment 2

[Simon Bünzli]

Comment on attachment 208782 [details] [diff] [review]
ignore leading '*'s

Gavin: Is this anything we might want?

Comment 3

[:Gavin Sharp [email: [e-mail]]]

Comment on attachment 208782 [details] [diff] [review]
ignore leading '*'s

Sorry for the delay. I'm very ambivalent about this patch... I don't think about:config performance for edge cases like these are really worth worrying about :)

Comment 4

[Dão Gottwald [:dao]]

Comment on attachment 208782 [details] [diff] [review]
ignore leading '*'s

>+      rex = RegExp(substring.replace(/([^* \w])/g, "\\$1")
>+        .replace(/^[*]+/, "").replace(/[*]+/g, ".*"), "i");

This should be more straightforward and is theoretically (doesn't matter, really) faster:

>      rex = RegExp(substring.replace(/([^* \w])/g, "\\$1")
>                            .replace(/^\*+/, "")
>                            .replace(/\*+/g, ".*"), "i");

Comment 5

[Simon Bünzli]

Attachment: for check-in

Comment 6

[:Gavin Sharp [email: [e-mail]]]

Comment on attachment 275233 [details] [diff] [review]
for check-in

You don't need approval for front end patches like this one, at this stage.

Comment 7

[:Gavin Sharp [email: [e-mail]]]

mozilla/toolkit/components/viewconfig/content/config.js 	1.24