On 2/27/17, Andy Bradford <amb-fos...@bradfords.org> wrote: > Thus said Richard Hipp on Mon, 27 Feb 2017 21:50:43 -0500: > >> (9) There are no changes to the file formats, other than relaxing the >> size constraint on artifact hashes - allowing hash to be greater than >> or equal to 40 characters rather than requiring it to be exactly 40 >> characters. > > The F-card in a manifest is currently defined as: > > F filename ?SHA1-hash? ?permissions? ?old-name? > > So the SHA1-hash will be a variable-length hash >= 40. How will a > program (including Fossil) that interprets the F-card know what hash > algorithm was used? Or will it not matter? Will it simply have to know > that Fossil uses X, Y and Z algorithms and to compute one of each until > a match is found (perhaps using length as an indicator)?
The length of the hash will help reduce the number of algorithms it has to try, perhaps to 1. But in the event that two or more algorithms with the same hash length are in play (ex: SHA2-256 and SHA3-256) it tries them one by one until it finds the match. > > Also, when choosing a P-card to include in a manifest, how will a choice > be made for hash to be included in the P-card? Likewise for the Q-card? It uses the display name of the referenced artifact - whatever hash is found in the BLOB.UUID column. > >> (11) URLs and command-line arguments can use either the display name >> or any of the aliases for an artifact. > > I assume that the same Ambiguous Artifact page that is used when a short > UUID is used will also be used when the aliases have similar length > collisions? e.g. the SHA1 hash 0005 might have a collision with a 4 > character prefix of a different SHA3-256 hash? Correct. The query that does this was formerly "SELECT rid FROM blob WHERE uuid GLOB '%q*'" with the %q being filled in by the prefix. This will need to change to add "... UNION ALL SELECT rid FROM alias WHERE hval GLOB '%q*'". I think that after that one change, everything should continue to work as before. > > Regarding: > >> (12) Web pages that show details about an artifact will be titled by >> the display name, but will also show all aliases. > > What about command line tools? This may seem off-the-wall, but I often > use a tty that is a standard 24 rows 80 columns: This is a good question and one that I do not have an answer for yet. My plan was to get the basic logic working first, and then afterwards get community help in tweaking the output format. -- D. Richard Hipp d...@sqlite.org _______________________________________________ fossil-dev mailing list fossil-dev@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/fossil-dev
