55065 - cache services in nsHTTPChannel

Status: VERIFIED FIXED

(Core :: Networking: HTTP, defect, P3)

Description

[Doug Turner (:dougt)]

There are about 10 calls to NS_WITH_SERVICE some of which can be factored into
the http channel's init call.


Bounce this back to me if want.

Comment 1

[Darin Fisher]

dougt: not sure exactly what you have in mind.  Are you suggesting that the
results of NS_WITH_SERVICE be "cached" in the http channel as either member
variables or static member variables?  With that in mind, what is the policy
on saving a pointer to an interface returned by NS_WITH_SERVICE?  Would the
result of NS_WITH_SERVICE ever change throughout the lifetime of a particular
mozilla instance?  I understand that if I want to cache the result of
NS_WITH_SERVICE in a global/static variable that I would have to provide the
appropriate thread synchronization code.  Are there any other gotchas that I
should be aware of if I were to go that route?

Comment 2

[Judson Valeski]

yea, NS_WITH_SERVICE's should be avoided when possible (thus caching the result
is a fine thing to do). You'd want to cache them as member variables (nsCOMPtrs
of course) so that when the channel went away, they'd go away too
(automattically). One of the rules of COM (subsequently XPCOM) is that once you
have a pointer to something, that pointer is valid until you release it. In
short, nothing can change underneath you as long as you hold a ref to it.

Comment 3

[Darin Fisher]

->me

Comment 4

[Darin Fisher]

done.. as of the http branch landing we cache many services in the http handler.

Comment 5

[John Unruh]

Verified per darin's comment.