299081 - nsScannerSharedSubstring::writable() is called too much

Status: NEW

(Core :: DOM: HTML Parser, defect, P5)

Description

[Blake Kaplan (:mrbkap) (inactive)]

When bryner introduced nsScannerSharedSubstring, he didn't add very much in the
way of functions that can "mutate" the string without actually making the string
mutable. As an example, it is impossible to call Truncate() on a
nsScannerSharedSubstring without calling writable() (if you're not using iterators).

I think it would be nice to implement functions such as Truncate() and maybe
AppendNextChar() (which would append the next character in the scanner to the
string) so that we wouldn't have to call writable() quite so much. (note: I'm
not sure if this would even matter or if there would be any sort of performance
gain).

Are there any opinions on this?

Comment 1

[Darin Fisher]

It sounds like you have a couple choices:

1) use quantify or some other profiler to figure out if this matters, and then
fix it if it actually does.

2) make the change because it makes the code cleaner (i.e., easier to maintain)

Comment 2

[Jens Stutte [:jstutte]]

Bulk-downgrade of unassigned, >=5 years untouched DOM/Storage bugs' priority.

If you have reason to believe this is wrong (especially for the severity), please write a comment and ni :jstutte.