414925 - openPrefFile could fail to read all data

Status: RESOLVED INVALID

(Core :: Preferences: Backend, defect, P1)

Description

[Mats Palmgren (inactive)]

I think this code could fail to read all data in the file:
http://bonsai.mozilla.org/cvsblame.cgi?file=/mozilla/modules/libpref/src/nsPrefService.cpp&rev=1.102&root=/cvsroot&mark=612#585
since you can get less than what you request:
http://bonsai.mozilla.org/cvsblame.cgi?file=/mozilla/xpcom/io/nsIInputStream.idl&rev=3.17&root=/cvsroot&mark=136,145#129

AFAICT, we really need a loop there, although you can still parse it in one
pass after you have all the data of course.

Comment 1

[Jim Mathies [:jimm]]

Ok, so we have to loop once to be sure the number of bytes read is zero on the second call. It might not, but usually it will be.

It seemed there was an added performance hit from the reiterative calls into the parser, so I was trying to avoid that. Sounds like with this change we would still get the gains 99% of the time.

Comment 2

[Mike Connor [:mconnor]]

We should fix this before b3...

Comment 3

[Jim Mathies [:jimm]]

I believe the plan is to pull it since some folks had some suggestions on  how to better implement it, which would then require retesting to see if we get any gains.

Comment 4

[Reed Loden [:reed]]

I backed the offending patch out.