view hgext/schemes.py @ 24992:7df090c9c9fe

localrepo: use changelog.hasnode instead of self.__contains__

Before this patch, releasing the store lock implies the actions below, when
the transaction is aborted:

  1. "commithook()" scheduled in "localrepository.commit()" is invoked
  2. "changectx.__init__()" is invoked via "self.__contains__()"
  3. specified ID is examined against "repo.dirstate.p1()"
  4. validation function is invoked in "dirstate.p1()"

In subsequent patches, "dirstate.invalidate()" invocations for
discarding changes are replaced with "dirstateguard", but discarding
changes by "dirstateguard" is executed after releasing the store lock:
resources are acquired in "wlock => dirstateguard => store lock" order,
and are released in reverse order.

This may cause that "dirstate.p1()" still refers to the changeset to be
rolled-back at (4) above: pushing multiple patches by "hg qpush" is
a typical case.

When releasing the store lock, such changesets are:

  - not contained in "repo.changelog", if it is reloaded from
    ".hg/00changelog.i", as that file was already truncated by
    "transaction.abort()"

  - still contained in it, otherwise
    (this "dirty read" problem is discussed in "Transaction Plan"
     http://mercurial.selenic.com/wiki/TransactionPlan)

Validation function shows "unknown working parent" warning in the
former case, but reloading "repo.changelog" depends on the timestamp
of ".hg/00changelog.i". This causes occasional test failures.

In the case of scheduled "commithook()", it just wants to examine
whether "node ID" of committed changeset is still valid or not. Other
examinations implied in "changectx.__init__()" are meaningless.

To avoid showing the "unknown working parent" warning irregularly, this
patch uses "changelog.hasnode()" instead of "node in self" to examine
existence of committed changeset.

# Copyright 2009, Alexander Solovyov <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

"""extend schemes with shortcuts to repository swarms

This extension allows you to specify shortcuts for parent URLs with a
lot of repositories to act like a scheme, for example::

  [schemes]
  py = http://code.python.org/hg/

After that you can use it like::

  hg clone py://trunk/

Additionally there is support for some more complex schemas, for
example used by Google Code::

  [schemes]
  gcode = http://{1}.googlecode.com/hg/

The syntax is taken from Mercurial templates, and you have unlimited
number of variables, starting with ``{1}`` and continuing with
``{2}``, ``{3}`` and so on. This variables will receive parts of URL
supplied, split by ``/``. Anything not specified as ``{part}`` will be
just appended to an URL.

For convenience, the extension adds these schemes by default::

  [schemes]
  py = http://hg.python.org/
  bb = https://bitbucket.org/
  bb+ssh = ssh://[e-mail]/
  gcode = https://{1}.googlecode.com/hg/
  kiln = https://{1}.kilnhg.com/Repo/

You can override a predefined scheme by defining a new scheme with the
same name.
"""

import os, re
from mercurial import extensions, hg, templater, util
from mercurial.i18n import _

testedwith = 'internal'


class ShortRepository(object):
    def __init__(self, url, scheme, templater):
        self.scheme = scheme
        self.templater = templater
        self.url = url
        try:
            self.parts = max(map(int, re.findall(r'\{(\d+)\}', self.url)))
        except ValueError:
            self.parts = 0

    def __repr__(self):
        return '<ShortRepository: %s>' % self.scheme

    def instance(self, ui, url, create):
        # Should this use the util.url class, or is manual parsing better?
        try:
            url = url.split('://', 1)[1]
        except IndexError:
            raise util.Abort(_("no '://' in scheme url '%s'") % url)
        parts = url.split('/', self.parts)
        if len(parts) > self.parts:
            tail = parts[-1]
            parts = parts[:-1]
        else:
            tail = ''
        context = dict((str(i + 1), v) for i, v in enumerate(parts))
        url = ''.join(self.templater.process(self.url, context)) + tail
        return hg._peerlookup(url).instance(ui, url, create)

def hasdriveletter(orig, path):
    if path:
        for scheme in schemes:
            if path.startswith(scheme + ':'):
                return False
    return orig(path)

schemes = {
    'py': 'http://hg.python.org/',
    'bb': 'https://bitbucket.org/',
    'bb+ssh': 'ssh://[e-mail]/',
    'gcode': 'https://{1}.googlecode.com/hg/',
    'kiln': 'https://{1}.kilnhg.com/Repo/'
    }

def extsetup(ui):
    schemes.update(dict(ui.configitems('schemes')))
    t = templater.engine(lambda x: x)
    for scheme, url in schemes.items():
        if (os.name == 'nt' and len(scheme) == 1 and scheme.isalpha()
            and os.path.exists('%s:\\' % scheme)):
            raise util.Abort(_('custom scheme %s:// conflicts with drive '
                               'letter %s:\\\n') % (scheme, scheme.upper()))
        hg.schemes[scheme] = ShortRepository(url, scheme, t)

    extensions.wrapfunction(util, 'hasdriveletter', hasdriveletter)