##// END OF EJS Templates
registrar: replace "cmdtype" with an intent-based mechanism (API)...
registrar: replace "cmdtype" with an intent-based mechanism (API) Commands perform varied actions and repositories vary in their capabilities. Historically, the .hg/requires file has been used to lock out clients lacking a requirement. But this is a very heavy-handed approach and is typically reserved for cases where the on-disk storage format changes and we want to prevent incompatible clients from operating on a repo. Outside of the .hg/requires file, we tend to deal with things like optional, extension-provided features via checking at call sites. We'll either have checks in core or extensions will monkeypatch functions in core disabling incompatible features, enabling new features, etc. Things are somewhat tolerable today. But once we introduce alternate storage backends with varying support for repository features and vastly different modes of behavior, the current model will quickly grow unwieldy. For example, the implementation of the "simple store" required a lot of hacks to deal with stripping and verify because various parts of core assume things are implemented a certain way. Partial clone will require new ways of modeling file data retrieval, because we can no longer assume that all file data is already local. In this new world, some commands might not make any sense for certain types of repositories. What we need is a mechanism to affect the construction of repository (and eventually peer) instances so the requirements/capabilities needed for the current operation can be taken into account. "Current operation" can almost certainly be defined by a command. So it makes sense for commands to declare their intended actions. This commit introduces the "intents" concept on the command registrar. "intents" captures a set of strings that declare actions that are anticipated to be taken, requirements the repository must possess, etc. These intents will be passed into hg.repo(), which will pass them into localrepository, where they can be used to influence the object being created. Some use cases for this include: * For read-only intents, constructing a repository object that doesn't expose methods that can mutate the repository. Its VFS instances don't even allow opening a file with write access. * For read-only intents, constructing a repository object without cache invalidation logic. If the repo never changes during its lifetime, nothing ever needs to be invalidated and we don't need to do expensive things like verify the changelog's hidden revisions state is accurate every time we access repo.changelog. * We can automatically hide commands from `hg help` when the current repository doesn't provide that command. For example, an alternate storage backend may not support `hg commit`, so we can hide that command or anything else that would perform local commits. We already kind of had an "intents" mechanism on the registrar in the form of "cmdtype." However, it was never used. And it was limited to a single value. We really need something that supports multiple intents. And because intents may be defined by extensions and at this point are advisory, I think it is best to define them in a set rather than as separate arguments/attributes on the command. Differential Revision: https://phab.mercurial-scm.org/D3376

File last commit:

r34646:75979c8d default
r37734:dfc51a48 default
Show More
rcutil.py
98 lines | 3.1 KiB | text/x-python | PythonLexer
# rcutil.py - utilities about config paths, special config sections etc.
#
# Copyright Mercurial Contributors
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import os
from . import (
encoding,
pycompat,
util,
)
if pycompat.iswindows:
from . import scmwindows as scmplatform
else:
from . import scmposix as scmplatform
fallbackpager = scmplatform.fallbackpager
systemrcpath = scmplatform.systemrcpath
userrcpath = scmplatform.userrcpath
def _expandrcpath(path):
'''path could be a file or a directory. return a list of file paths'''
p = util.expandpath(path)
if os.path.isdir(p):
join = os.path.join
return [join(p, f) for f, k in util.listdir(p) if f.endswith('.rc')]
return [p]
def envrcitems(env=None):
'''Return [(section, name, value, source)] config items.
The config items are extracted from environment variables specified by env,
used to override systemrc, but not userrc.
If env is not provided, encoding.environ will be used.
'''
if env is None:
env = encoding.environ
checklist = [
('EDITOR', 'ui', 'editor'),
('VISUAL', 'ui', 'editor'),
('PAGER', 'pager', 'pager'),
]
result = []
for envname, section, configname in checklist:
if envname not in env:
continue
result.append((section, configname, env[envname], '$%s' % envname))
return result
def defaultrcpath():
'''return rc paths in default.d'''
path = []
defaultpath = os.path.join(util.datapath, 'default.d')
if os.path.isdir(defaultpath):
path = _expandrcpath(defaultpath)
return path
def rccomponents():
'''return an ordered [(type, obj)] about where to load configs.
respect $HGRCPATH. if $HGRCPATH is empty, only .hg/hgrc of current repo is
used. if $HGRCPATH is not set, the platform default will be used.
if a directory is provided, *.rc files under it will be used.
type could be either 'path' or 'items', if type is 'path', obj is a string,
and is the config file path. if type is 'items', obj is a list of (section,
name, value, source) that should fill the config directly.
'''
envrc = ('items', envrcitems())
if 'HGRCPATH' in encoding.environ:
# assume HGRCPATH is all about user configs so environments can be
# overridden.
_rccomponents = [envrc]
for p in encoding.environ['HGRCPATH'].split(pycompat.ospathsep):
if not p:
continue
_rccomponents.extend(('path', p) for p in _expandrcpath(p))
else:
normpaths = lambda paths: [('path', os.path.normpath(p)) for p in paths]
_rccomponents = normpaths(defaultrcpath() + systemrcpath())
_rccomponents.append(envrc)
_rccomponents.extend(normpaths(userrcpath()))
return _rccomponents
def defaultpagerenv():
'''return a dict of default environment variables and their values,
intended to be set before starting a pager.
'''
return {'LESS': 'FRX', 'LV': '-c'}