From:  Jason Duell <>
Date:  20 Dec 2015 07:36:57 Hong Kong Time

Re: devtools re-fetching problem


On Fri, Dec 18, 2015 at 6:15 PM, Ehsan Akhgari 

> On 2015-12-18 4:56 PM, Tom Tromey wrote:
>> I mentioned this on #necko the other day.
>> We've had a "re-fetching" problem in devtools for a while now.
>> The basic issue is that the platform drops the original text of some
>> things, like style sheets.  (Instead just the parsed form is preserved.)
>> So, in order to make some tools work with the source text, devtools
>> re-fetches the sources.  However, this is sub-optimal -- maybe the
>> sources have changed on the server, leading to confusing results.
>> We were wondering if there was some way we could solve this problem.
>> One idea we had is to always cache these things, in a way that would let
>> the devtools retrieve them.  Is this possible?
> We can't cache the resources if the web server tells us "don't cache
> this", so even if we use things such as LOAD_ONLY_FROM_CACHE, we still need
> a solution for that case.
> Or ... some other idea here.
> How about forcing Gecko retain the original source text when devtools are
> being used?

Sounds like we need something like a CACHE_GECKO_COPY flag that keeps a
"secret" cache only for internal gecko use?

1) if the resource would normally be cached, does nothing (the resource
gets cached normally)
2) If the resource wouldn't be cached, cache it (perhaps only in RAM?  Or
maybe we'd need that only if INHIBIT_PERSISTENT_CACHING is set), with some
sort of flag that indicates it should be invisible to cache reads unless
CACHE_HIDDEN_COPY is again present.


P.S. Honza/Michal: right now nsIRequest.idl says that "For HTTPS,
[INHIBIT_PERSISTENT_CACHING] is set automatically."  That's out of date now
IIRC--we should change the comment.