mercurial/pushkey.py

registrar: add funcregistrar class to register function for specific purpose

This class centralizes the common logic to register function for
specific purpose like below:

    - template keyword, filter and function
    - revset predicate
    - fileset predicate
    - webcommand

'funcregistrar' also formats help document of the function with the
'decl'(aration) specified at the construction.

This can avoid (1) redundancy between 'decl' and help document, and
(2) accidental typo of help document. For example, 'foo' should appear
twice like below, if without such formatting:

    @keyword('foo')
    def foo(....):
        """:foo: Explanation of keyword foo ..."""

Almost all cases needs very simple document formatting like below:

    - "``DECL``\n    EXPLANATION"
    - ":DECL: EXPLANATION"

But webcommand needs a little complicated formatting like:

    /PATH/SPEC
    ----------

    EXPLANATION ....

To make minirst recognize the section header, hyphen line should be as
long as "/PATH/SPEC". It should be arranged by program.

Implementing 'formatdoc()' in derived class can support complicated
formatting in the latter case. But it seems redundant for simple one
in the former case.

Therefore, 'funcregistrar' does:

    - invoke 'self.formatdoc', if it is callable (for the latter case)
    - use it as the format string, otherwise (for the former case)

# 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