revisionbranchcache: fall back to slow path if starting readonly (issue4531)
Transitioning to Mercurial versions with revision branch cache could be slow as
long as all operations were readonly (revset queries) and the cache would be
populated but not written back.
Instead, fall back to using the consistently slow path when readonly and the
cache doesn't exist yet. That avoids the overhead of populating the cache
without writing it back.
If not readonly, it will still populate all missing entries initially. That
avoids repeated writing of the cache file with small updates, and it also makes
sure a fully populated cache available for the readonly operations.
# Copyright 2009, Alexander Solovyov <piranha@piranha.org.ua>
#
# 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://hg@bitbucket.org/
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://hg@bitbucket.org/',
'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)