76     revlogutils,

   990 

   991 

   992 @command(

   993     b'debug-delta-find',

   994     cmdutil.debugrevlogopts + cmdutil.formatteropts,

   995     _(b'-c|-m|FILE REV'),

   996     optionalrepo=True,

   997 )

   998 def debugdeltafind(ui, repo, arg_1, arg_2=None, **opts):

   999     """display the computation to get to a valid delta for storing REV

  1000 

  1001     This command will replay the process used to find the "best" delta to store

  1002     a revision and display information about all the steps used to get to that

  1003     result.

  1004 

  1005     The revision use the revision number of the target storage (not changelog

  1006     revision number).

  1007 

  1008     note: the process is initiated from a full text of the revision to store.

  1009     """

  1010     opts = pycompat.byteskwargs(opts)

  1011     if arg_2 is None:

  1012         file_ = None

  1013         rev = arg_1

  1014     else:

  1015         file_ = arg_1

  1016         rev = arg_2

  1017 

  1018     rev = int(rev)

  1019 

  1020     revlog = cmdutil.openrevlog(repo, b'debugdeltachain', file_, opts)

  1021 

  1022     deltacomputer = deltautil.deltacomputer(

  1023         revlog,

  1024         write_debug=ui.write,

  1025         debug_search=True,

  1026     )

  1027 

  1028     node = revlog.node(rev)

  1029     p1r, p2r = revlog.parentrevs(rev)

  1030     p1 = revlog.node(p1r)

  1031     p2 = revlog.node(p2r)

  1032     btext = [revlog.revision(rev)]

  1033     textlen = len(btext[0])

  1034     cachedelta = None

  1035     flags = revlog.flags(rev)

  1036 

  1037     revinfo = revlogutils.revisioninfo(

  1038         node,

  1039         p1,

  1040         p2,

  1041         btext,

  1042         textlen,

  1043         cachedelta,

  1044         flags,

  1045     )

  1046 

  1047     fh = revlog._datafp()

  1048     deltacomputer.finddeltainfo(revinfo, fh, target_rev=rev)