[darcs-devel] New Patch Format sticky spots

[David Roundy]

(David emerges from the mist, after a time of being awfully sick...)

On Sat, Apr 22, 2006 at 08:26:20PM +0100, Ian Lynagh wrote:
> On Sat, Apr 22, 2006 at 10:15:07AM -0700, Jason Dagit wrote:
> > 
> > I found some time tonight to start implementing a different format for
> > hunks.  Very simple but meant to allow skipping over data.
> > 
> > hunk <filename> <line#> <#bytes of old content> <#bytes new content>
> > <dump of old lines><dump of new lines>
> 
> I don't know where in the list archives or bug trackers it is OTTOMH,
> but what the new format should look like has been discussed before.
> 
> I think it looked something like
> 
> hunk <file> <byte#> <line#> <#old bytes> <#old lines> <#new bytes> <#new lines>
> old:
> <the old data>
> new:
> <the new data>

I don't think we can have a byte# field in the hunk patch, as it'd make it
impossible to commute with replace patches, since the replace patch will
modify the byte# in a way that can't be computed using just the patches
themselves.  So I think we'll need to leave that optimization out for now.
One could add it back in, if a replace patch stored the locations (perhaps
both line# and byte#?) of all the matches it makes.  But that's a seriously
big change, and I don't think the improvement in speed of applying hunk
patches will be worth the effort, at least at this stage.

I think this is something I just didn't think of when you proposed this
patch format before.
-- 
David Roundy
http://www.darcs.net