view hgext/schemes.py @ 46843:728d89f6f9b1

refactor: prefer checks against nullrev over nullid

A common pattern is using a changeset context and obtaining the node to
compare against nullid. Change this to obtain the nullrev instead. In
the future, the nullid becomes a property of the repository and is no
longer a global constant, so using nullrev is much easier to reason
about. Python function call overhead makes the difference moot, but
future changes will result in more dictionary lookups otherwise, so
prefer the simpler pattern.

Differential Revision: https://phab.mercurial-scm.org/D10290

# 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.
"""
from __future__ import absolute_import

import os
import re

from mercurial.i18n import _
from mercurial import (
    error,
    extensions,
    hg,
    pycompat,
    registrar,
    templater,
    util,
)

cmdtable = {}
command = registrar.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b'ships-with-hg-core'

_partre = re.compile(br'{(\d+)\}')


class ShortRepository(object):
    def __init__(self, url, scheme, templater):
        self.scheme = scheme
        self.templater = templater
        self.url = url
        try:
            self.parts = max(map(int, _partre.findall(self.url)))
        except ValueError:
            self.parts = 0

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

    def instance(self, ui, url, create, intents=None, createopts=None):
        url = self.resolve(url)
        return hg._peerlookup(url).instance(
            ui, url, create, intents=intents, createopts=createopts
        )

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


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


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


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

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


@command(b'debugexpandscheme', norepo=True)
def expandscheme(ui, url, **opts):
    """given a repo path, provide the scheme-expanded path"""
    repo = hg._peerlookup(url)
    if isinstance(repo, ShortRepository):
        url = repo.resolve(url)
    ui.write(url + b'\n')