mercurial/fancyopts.py

branches: avoid unnecessary changectx.branch() calls

This requires reading from the changelog, which can be costly over NFS.

Note that this does not totally remove reading from the changelog; we
still do that when calling changectx.closesbranch(). That call will be
removed in a later patch.

Running hg branches on the PyPy repo (with 996) over a busy NFS server,
before this change:

$ time hg --profile branches > /dev/null
   CallCount    Recursive     Total(s)    Inline(s) module:lineno(function)
        2042            0      2.2827      2.2827   <open>
        2036            0      0.9840      0.9840   <method 'close' of 'file' objects>
        2036            0      0.0464      0.0464   <method 'read' of 'file' objects>
        5233            0      0.1985      0.0453   mercurial.repoview:161(changelog)
       10462            0      0.0791      0.0314       mercurial.changelog:133(tip)
        5233            0      0.0388      0.0176       mercurial.localrepo:26(__get__)
       10462            0      0.0250      0.0126       <len>
        5233            0      0.0059      0.0039       mercurial.repoview:112(filterrevs)
       10462            0      0.0029      0.0029       <hash>
        2034            0      0.0444      0.0444   <method 'seek' of 'file' objects>
        5340            0      0.0390      0.0390   mercurial.revlog:296(rev)
        2582            0      0.0371      0.0371   <zlib.decompress>
        3155            0      0.1963      0.0366   mercurial.context:202(__init__)
        3155            0      0.1238      0.0306       mercurial.repoview:161(changelog)
        3155            0      0.0261      0.0080       mercurial.changelog:183(rev)
        9465            0      0.0061      0.0061       <isinstance>
        1096            0      0.0023      0.0023       <binascii.unhexlify>
        4251            0      0.0014      0.0014       <len>
        2059            0      3.7341      0.0332   mercurial.changelog:270(read)
        2059            0      3.6304      0.0307       mercurial.revlog:907(revision)
        2057            0      0.0262      0.0137       mercurial.changelog:28(decodeextra)
        4118            0      0.0094      0.0094       <method 'split' of 'str' objects>
        4118            0      0.0270      0.0048       mercurial.encoding:61(tolocal)
        2059            0      0.0040      0.0040       <method 'index' of 'str' objects>
       10462            0      0.0791      0.0314   mercurial.changelog:133(tip)
       10462            0      0.0289      0.0207       mercurial.changelog:190(node)
       10462            0      0.0188      0.0091       <len>
       52433        20932      0.0478      0.0310   <len>
       20932            0      0.0221      0.0168       mercurial.revlog:262(__len__)
        2059            0      3.6304      0.0307   mercurial.revlog:907(revision)

real    0m4.361s
user    0m0.986s
sys     0m0.237s

After this change:

$ time hg --profile branches > /dev/null
   CallCount    Recursive     Total(s)    Inline(s) module:lineno(function)
        1069            0      1.1098      1.1098   <open>
        1063            0      0.4865      0.4865   <method 'close' of 'file' objects>
        4122            0      0.1811      0.0404   mercurial.repoview:161(changelog)
        8240            0      0.0712      0.0272       mercurial.changelog:133(tip)
        4122            0      0.0378      0.0177       mercurial.localrepo:26(__get__)
        8240            0      0.0221      0.0115       <len>
        4122            0      0.0057      0.0033       mercurial.repoview:112(filterrevs)
        8240            0      0.0025      0.0025       <hash>
        3029            0      0.1979      0.0371   mercurial.context:202(__init__)
        3029            0      0.1278      0.0310       mercurial.repoview:161(changelog)
        3029            0      0.0230      0.0081       mercurial.changelog:183(rev)
        9087            0      0.0061      0.0061       <isinstance>
        1096            0      0.0026      0.0026       <binascii.unhexlify>
        4125            0      0.0014      0.0014       <len>
        4229            0      0.0337      0.0337   mercurial.revlog:296(rev)
        1061            0      0.0296      0.0296   <method 'seek' of 'file' objects>
        1063            0      0.0292      0.0292   <method 'read' of 'file' objects>
        8240            0      0.0712      0.0272   mercurial.changelog:133(tip)
        8240            0      0.0271      0.0196       mercurial.changelog:190(node)
        8240            0      0.0169      0.0083       <len>
       40476        16488      0.0422      0.0271   <len>
       16488            0      0.0193      0.0152       mercurial.revlog:262(__len__)
        1342            0      0.0241      0.0241   <zlib.decompress>
        9445            0      0.0336      0.0224   mercurial.changelog:190(node)
        9445            0      0.0112      0.0112       mercurial.revlog:317(node)
        1074            0      1.9102      0.0224   mercurial.changelog:270(read)
        1074            0      1.8397      0.0202       mercurial.revlog:907(revision)
        1073            0      0.0187      0.0099       mercurial.changelog:28(decodeextra)
        2148            0      0.0061      0.0061       <method 'split' of 'str' objects>
        2148            0      0.0184      0.0034       mercurial.encoding:61(tolocal)

real    0m2.402s
user    0m0.735s
sys     0m0.177s

# fancyopts.py - better command line parsing
#
#  Copyright 2005-2009 Matt Mackall <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import getopt
import util
from i18n import _

def gnugetopt(args, options, longoptions):
    """Parse options mostly like getopt.gnu_getopt.

    This is different from getopt.gnu_getopt in that an argument of - will
    become an argument of - instead of vanishing completely.
    """
    extraargs = []
    if '--' in args:
        stopindex = args.index('--')
        extraargs = args[stopindex + 1:]
        args = args[:stopindex]
    opts, parseargs = getopt.getopt(args, options, longoptions)
    args = []
    while parseargs:
        arg = parseargs.pop(0)
        if arg and arg[0] == '-' and len(arg) > 1:
            parseargs.insert(0, arg)
            topts, newparseargs = getopt.getopt(parseargs, options, longoptions)
            opts = opts + topts
            parseargs = newparseargs
        else:
            args.append(arg)
    args.extend(extraargs)
    return opts, args


def fancyopts(args, options, state, gnu=False):
    """
    read args, parse options, and store options in state

    each option is a tuple of:

      short option or ''
      long option
      default value
      description
      option value label(optional)

    option types include:

      boolean or none - option sets variable in state to true
      string - parameter string is stored in state
      list - parameter string is added to a list
      integer - parameter strings is stored as int
      function - call function with parameter

    non-option args are returned
    """
    namelist = []
    shortlist = ''
    argmap = {}
    defmap = {}

    for option in options:
        if len(option) == 5:
            short, name, default, comment, dummy = option
        else:
            short, name, default, comment = option
        # convert opts to getopt format
        oname = name
        name = name.replace('-', '_')

        argmap['-' + short] = argmap['--' + oname] = name
        defmap[name] = default

        # copy defaults to state
        if isinstance(default, list):
            state[name] = default[:]
        elif getattr(default, '__call__', False):
            state[name] = None
        else:
            state[name] = default

        # does it take a parameter?
        if not (default is None or default is True or default is False):
            if short:
                short += ':'
            if oname:
                oname += '='
        if short:
            shortlist += short
        if name:
            namelist.append(oname)

    # parse arguments
    if gnu:
        parse = gnugetopt
    else:
        parse = getopt.getopt
    opts, args = parse(args, shortlist, namelist)

    # transfer result to state
    for opt, val in opts:
        name = argmap[opt]
        t = type(defmap[name])
        if t is type(fancyopts):
            state[name] = defmap[name](val)
        elif t is type(1):
            try:
                state[name] = int(val)
            except ValueError:
                raise util.Abort(_('invalid value %r for option %s, '
                                   'expected int') % (val, opt))
        elif t is type(''):
            state[name] = val
        elif t is type([]):
            state[name].append(val)
        elif t is type(None) or t is type(False):
            state[name] = True

    # return unparsed args
    return args