On 02/04/2012 01:10 PM, Hyrum K Wright wrote: > On Sat, Feb 4, 2012 at 10:59 AM, Julian Foad <julianf...@btopenworld.com> > wrote: >> I'm not quite sure I fully follow you at the moment, so I'm not sure if my >> reply is on the right track at all, but it's really sounding like you're up >> against a mis-match of responsibilities between Ev1 which sends deltas >> according to particular rules and Ev2 which is designed to be wrapped inside >> a driver-receiver pairing that knows privately how to deltify and recover to >> full text in any way it wants to. The shims obviously need to convert from >> the Ev2 deltification back (via a full text intermediary if necessary) to >> what Ev1 expects. > > What's driving this discussion is this: Up until this point in the > Ev2 shims we've been supplying a NULL base checksum for apply > textdelta, which the receivers have dutifully ignored. However, when > the Ev2 shims attempt to be honest about the fact that they are using > the empty stream for the text base, the receivers start complaining, > because that's not what they expected---even though the end result is > the same. In essence, all these checks are returning false positives, > which is extremely unpleasant. > > I don't know that there is an easy way around this, since by the time > we're translated from Ev2->delta-editor, we don't have the original > text base, or its checksum, available to us. We have the full text, > which is the reason the new text base is the empty stream: it's the > only one we need. > > Does that make any sense?
Yeah, sounds like we're in a tough spot here. The checksums in Ev1 exist only as sanity checks -- they definitely are NOT the primary selection mechanism for the editor implementation's base text. I assume we still have a valid checksum to pass to close_file() (the checksum of the post-edit fulltext for that file), right? It's just the pre-edit base checksum that's the problem? -- C. Michael Pilato <cmpil...@collab.net> CollabNet <> www.collab.net <> Distributed Development On Demand
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