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Re: [RFC] Plumbing-only support for storing object metadata

From
Shawn O. Pearce <spearce@spearce.org>
Date
Aug 18, 2008, 06:12 UTC
Message-ID
<20080818061236.GF7376@spearce.org>
In-Reply-To
<20080816062130.GA4554@oh.minilop.net>
Josh Triplett <josh@freedesktop.org>, Jamey Sharp <jamey@minilop.net> wrote:
Show 13 quoted lines
> On Sat, Aug 09, 2008 at 08:51:01PM -0700, Shawn O. Pearce wrote:
> > Nico and I have (at least in the past) agreed that type 0 is meant
> > as an escape indicator.  If the type is set to 0 then the real type
> > code appears in another byte of data which follows the object's
> > inflated length.
> >
> > That leaves only type 5 available.
> [...]
> > So yea, there really aren't any new type bits available.
> 
> If consensus opinion was that new object types were a reasonable way to
> solve this problem, then it sounds as if there's plenty of room to
> create new types using this escape mechanism.

Yes, but we'd hate to see the majority of the encodings within a pack using the escape mechanism.

So a lot of my argument here was just trying to point out that type bits aren't free, and we need to make sure the limited ones available are applied to the majority of the pack contents.

Adding a new type bit is a lot more than just adding it to the pack data field. Look at the amount of code that needed to be changed to support gitlink in trees, and that was "reusing" the OBJ_COMMIT type. Anytime you start poking at the core object enumeration code with new cases there's a lot of corners that are affected.

-- 
Shawn.
Previous: Jan HudecNext: Derek Fawcus
Message 17 of 22 in “[RFC] Plumbing-only support for storing object metadata”
  1. Jamey SharpAug 9, 2008
  2. Scott ChaconAug 9, 2008
  3. Shawn O. PearceAug 10, 2008
  4. Stephen R. van den BergAug 10, 2008
  5. david@lang.hmAug 10, 2008
  6. Jan HudecAug 10, 2008
  7. Stephen R. van den BergAug 10, 2008
  8. Jan HudecAug 10, 2008
  9. Stephen R. van den BergAug 10, 2008
  10. Junio C HamanoAug 10, 2008
  11. david@lang.hmAug 10, 2008
  12. Stephen R. van den BergAug 11, 2008
  13. Josh TriplettAug 16, 2008
  14. david@lang.hmAug 16, 2008
  15. Junio C HamanoAug 16, 2008
  16. Jan HudecAug 16, 2008
  17. Shawn O. PearceAug 18, 2008
  18. Derek FawcusAug 18, 2008
  19. Shawn O. PearceAug 18, 2008
  20. Marcus GriepAug 18, 2008
  21. Shawn O. PearceAug 18, 2008
  22. Jan HudecAug 10, 2008

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