view mercurial/pushkey.py @ 27223:a40c84defd76

mercurial: be more strict about loading dual implemented modules

With this change in place, we should have slightly stronger guarantees
about how modules with both Python and C implementations are loaded.
Before, our module loader's default policy looked under both mercurial/*
and mercurial/pure/* and imported whatever it found, C or pure. The fact
it looked in both locations by default was a temporary regression from
the beginning of this series.

This patch does 2 things:

1) Changes the default module load policy to only load C modules
2) Verifies that files loaded from mercurial/* are actually C modules

This 2nd behavior change makes our new module loading mechanism
stricter than from before this series. Before, it was possible to load
a .py-based module from mercurial/*. This could happen if an old
installation orphaned a file and then somehow didn't install the C
version for the new install. We now detect this odd configuration
and fall back to loading the pure Python module, assuming it is
allowed. In the case of a busted installation, we fail fast. While
we could fall back, we explicitly decide not to do this because
we don't want people accidentally not running the C modules and having
slow performance as a result.

# pushkey.py - dispatching for pushing and pulling keys
#
# Copyright 2010 Matt Mackall <[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.

from __future__ import absolute_import

from . import (
    bookmarks,
    encoding,
    obsolete,
    phases,
)

def _nslist(repo):
    n = {}
    for k in _namespaces:
        n[k] = ""
    if not obsolete.isenabled(repo, obsolete.exchangeopt):
        n.pop('obsolete')
    return n

_namespaces = {"namespaces": (lambda *x: False, _nslist),
               "bookmarks": (bookmarks.pushbookmark, bookmarks.listbookmarks),
               "phases": (phases.pushphase, phases.listphases),
               "obsolete": (obsolete.pushmarker, obsolete.listmarkers),
              }

def register(namespace, pushkey, listkeys):
    _namespaces[namespace] = (pushkey, listkeys)

def _get(namespace):
    return _namespaces.get(namespace, (lambda *x: False, lambda *x: {}))

def push(repo, namespace, key, old, new):
    '''should succeed iff value was old'''
    pk = _get(namespace)[0]
    return pk(repo, key, old, new)

def list(repo, namespace):
    '''return a dict'''
    lk = _get(namespace)[1]
    return lk(repo)

encode = encoding.fromlocal

decode = encoding.tolocal

def encodekeys(keys):
    """encode the content of a pushkey namespace for exchange over the wire"""
    return '\n'.join(['%s\t%s' % (encode(k), encode(v)) for k, v in keys])

def decodekeys(data):
    """decode the content of a pushkey namespace from exchange over the wire"""
    result = {}
    for l in data.splitlines():
        k, v = l.split('\t')
        result[decode(k)] = decode(v)
    return result