751 

   752 @command('debugdeltachain',

   753     commands.debugrevlogopts + commands.formatteropts,

   754     _('-c|-m|FILE'),

   755     optionalrepo=True)

   756 def debugdeltachain(ui, repo, file_=None, **opts):

   757     """dump information about delta chains in a revlog

   758 

   759     Output can be templatized. Available template keywords are:

   760 

   761     :``rev``:       revision number

   762     :``chainid``:   delta chain identifier (numbered by unique base)

   763     :``chainlen``:  delta chain length to this revision

   764     :``prevrev``:   previous revision in delta chain

   765     :``deltatype``: role of delta / how it was computed

   766     :``compsize``:  compressed size of revision

   767     :``uncompsize``: uncompressed size of revision

   768     :``chainsize``: total size of compressed revisions in chain

   769     :``chainratio``: total chain size divided by uncompressed revision size

   770                     (new delta chains typically start at ratio 2.00)

   771     :``lindist``:   linear distance from base revision in delta chain to end

   772                     of this revision

   773     :``extradist``: total size of revisions not part of this delta chain from

   774                     base of delta chain to end of this revision; a measurement

   775                     of how much extra data we need to read/seek across to read

   776                     the delta chain for this revision

   777     :``extraratio``: extradist divided by chainsize; another representation of

   778                     how much unrelated data is needed to load this delta chain

   779     """

   780     r = cmdutil.openrevlog(repo, 'debugdeltachain', file_, opts)

   781     index = r.index

   782     generaldelta = r.version & revlog.REVLOGGENERALDELTA

   783 

   784     def revinfo(rev):

   785         e = index[rev]

   786         compsize = e[1]

   787         uncompsize = e[2]

   788         chainsize = 0

   789 

   790         if generaldelta:

   791             if e[3] == e[5]:

   792                 deltatype = 'p1'

   793             elif e[3] == e[6]:

   794                 deltatype = 'p2'

   795             elif e[3] == rev - 1:

   796                 deltatype = 'prev'

   797             elif e[3] == rev:

   798                 deltatype = 'base'

   799             else:

   800                 deltatype = 'other'

   801         else:

   802             if e[3] == rev:

   803                 deltatype = 'base'

   804             else:

   805                 deltatype = 'prev'

   806 

   807         chain = r._deltachain(rev)[0]

   808         for iterrev in chain:

   809             e = index[iterrev]

   810             chainsize += e[1]

   811 

   812         return compsize, uncompsize, deltatype, chain, chainsize

   813 

   814     fm = ui.formatter('debugdeltachain', opts)

   815 

   816     fm.plain('    rev  chain# chainlen     prev   delta       '

   817              'size    rawsize  chainsize     ratio   lindist extradist '

   818              'extraratio\n')

   819 

   820     chainbases = {}

   821     for rev in r:

   822         comp, uncomp, deltatype, chain, chainsize = revinfo(rev)

   823         chainbase = chain[0]

   824         chainid = chainbases.setdefault(chainbase, len(chainbases) + 1)

   825         basestart = r.start(chainbase)

   826         revstart = r.start(rev)

   827         lineardist = revstart + comp - basestart

   828         extradist = lineardist - chainsize

   829         try:

   830             prevrev = chain[-2]

   831         except IndexError:

   832             prevrev = -1

   833 

   834         chainratio = float(chainsize) / float(uncomp)

   835         extraratio = float(extradist) / float(chainsize)

   836 

   837         fm.startitem()

   838         fm.write('rev chainid chainlen prevrev deltatype compsize '

   839                  'uncompsize chainsize chainratio lindist extradist '

   840                  'extraratio',

   841                  '%7d %7d %8d %8d %7s %10d %10d %10d %9.5f %9d %9d %10.5f\n',

   842                  rev, chainid, len(chain), prevrev, deltatype, comp,

   843                  uncomp, chainsize, chainratio, lineardist, extradist,

   844                  extraratio,

   845                  rev=rev, chainid=chainid, chainlen=len(chain),

   846                  prevrev=prevrev, deltatype=deltatype, compsize=comp,

   847                  uncompsize=uncomp, chainsize=chainsize,

   848                  chainratio=chainratio, lindist=lineardist,

   849                  extradist=extradist, extraratio=extraratio)

   850 

   851     fm.end()