view hgext/alias.py @ 6144:08e0825b8106

revlog.revision: avoid opening the datafile without need.

If there's no inline data, revlog.revision opens the data file every
time it's called.  This is useful if we're going to call chunk many
times, but, if we're going to call it only once, it's better to let
chunk open the file - if we're lucky, all the data we're going to need
is already cached and we won't need to even look at the file.

# Copyright (C) 2007 Brendan Cully <[e-mail]>
# This file is published under the GNU GPL.

'''allow user-defined command aliases

To use, create entries in your hgrc of the form

[alias]
mycmd = cmd --args
'''

from mercurial.cmdutil import findcmd, UnknownCommand, AmbiguousCommand
from mercurial import commands

cmdtable = {}

class RecursiveCommand(Exception): pass

class lazycommand(object):
    '''defer command lookup until needed, so that extensions loaded
    after alias can be aliased'''
    def __init__(self, ui, name, target):
        self._ui = ui
        self._name = name
        self._target = target
        self._cmd = None

    def __len__(self):
        self._resolve()
        return len(self._cmd)

    def __getitem__(self, key):
        self._resolve()
        return self._cmd[key]

    def __iter__(self):
        self._resolve()
        return self._cmd.__iter__()

    def _resolve(self):
        if self._cmd is not None:
            return

        try:
            self._cmd = findcmd(self._ui, self._target, commands.table)[1]
            if self._cmd == self:
                raise RecursiveCommand()
            if self._target in commands.norepo.split(' '):
                commands.norepo += ' %s' % self._name
            return
        except UnknownCommand:
            msg = '*** [alias] %s: command %s is unknown' % \
                  (self._name, self._target)
        except AmbiguousCommand:
            msg = '*** [alias] %s: command %s is ambiguous' % \
                  (self._name, self._target)
        except RecursiveCommand:
            msg = '*** [alias] %s: circular dependency on %s' % \
                  (self._name, self._target)
        def nocmd(*args, **opts):
            self._ui.warn(msg + '\n')
            return 1
        nocmd.__doc__ = msg
        self._cmd = (nocmd, [], '')
        commands.norepo += ' %s' % self._name

def uisetup(ui):
    for cmd, target in ui.configitems('alias'):
        if not target:
            ui.warn('*** [alias] %s: no definition\n' % cmd)
            continue
        args = target.split(' ')
        tcmd = args.pop(0)
        if args:
            ui.setconfig('defaults', cmd, ' '.join(args))
        cmdtable[cmd] = lazycommand(ui, cmd, tcmd)