280386 - Add sanity checking to nsScanner::SetPosition()

Status: RESOLVED FIXED

(Core :: DOM: HTML Parser, defect)

Description

[Blake Kaplan (:mrbkap) (inactive)]

In the past month or so (especially after bryner's string changes), we've had a
few bugs pop up because of incorrect use of nsScanner::SetPosition(). In
general, these bugs are hard to catch (unless they trigger a crash) since the
most noticeable side effect of the bad calls are that the mCountRemaining member
variable becomes extremely large, leading to strange bugs (like bug 273085,
where Peek() was returning NS_OK, while giving a garbage result because it
relies on mCountRemaining).

I've added an assertion to the function that should catch most (if not all)
problems of this sort in an easier to spot place (when the bad call is made) as
opposed to the problem showing up in a random way down the line.

Comment 1

[Blake Kaplan (:mrbkap) (inactive)]

Attachment: Add an assertion

Comment 2

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 172848 [details] [diff] [review]
Add an assertion

r=bzbarsky

Comment 3

[Johnny Stenback (:jst)]

Comment on attachment 172848 [details] [diff] [review]
Add an assertion

sr=jst

Comment 4

[Blake Kaplan (:mrbkap) (inactive)]

Fix checked in.