mercurial/registrar.py

log: fix order of revisions filtered by multiple OR options (issue5100)

This is the simplest workaround for the issue of the ordering of revset, which
is that the expression "x or y" takes over the ordering specified by the input
set (or the left-hand-side expression.) For example, the following expression

  A & (x | y)

will be evaluated as if

  (A & x) | (A & y)

That's wrong because revset has ordering. I'm going to fix this problem in
the revset module, but that wouldn't fit to stable. So, this patch just works
around the common log cases.

Since this change might have some impact on performance, it is enabled only
if the expression built from log options has ' or ' operation.

# registrar.py - utilities to register function for specific purpose
#
#  Copyright FUJIWARA Katsunori <[e-mail]> and others
#
# 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 (
    util,
)

class funcregistrar(object):
    """Base of decorator to register a fuction for specific purpose

    The least derived class can be defined by overriding 'table' and
    'formatdoc', for example::

        symbols = {}
        class keyword(funcregistrar):
            table = symbols
            formatdoc = ":%s: %s"

        @keyword('bar')
        def barfunc(*args, **kwargs):
            '''Explanation of bar keyword ....
            '''
            pass

    In this case:

    - 'barfunc' is registered as 'bar' in 'symbols'
    - online help uses ":bar: Explanation of bar keyword"
    """

    def __init__(self, decl):
        """'decl' is a name or more descriptive string of a function

        Specification of 'decl' depends on registration purpose.
        """
        self.decl = decl

    table = None

    def __call__(self, func):
        """Execute actual registration for specified function
        """
        name = self.getname()

        if func.__doc__ and not util.safehasattr(func, '_origdoc'):
            doc = func.__doc__.strip()
            func._origdoc = doc
            if callable(self.formatdoc):
                func.__doc__ = self.formatdoc(doc)
            else:
                # convenient shortcut for simple format
                func.__doc__ = self.formatdoc % (self.decl, doc)

        self.table[name] = func
        self.extraaction(name, func)

        return func

    def getname(self):
        """Return the name of the registered function from self.decl

        Derived class should override this, if it allows more
        descriptive 'decl' string than just a name.
        """
        return self.decl

    def parsefuncdecl(self):
        """Parse function declaration and return the name of function in it
        """
        i = self.decl.find('(')
        if i > 0:
            return self.decl[:i]
        else:
            return self.decl

    def formatdoc(self, doc):
        """Return formatted document of the registered function for help

        'doc' is '__doc__.strip()' of the registered function.

        If this is overridden by non-callable object in derived class,
        such value is treated as "format string" and used to format
        document by 'self.formatdoc % (self.decl, doc)' for convenience.
        """
        raise NotImplementedError()

    def extraaction(self, name, func):
        """Execute exra action for registered function, if needed
        """
        pass

class delayregistrar(object):
    """Decorator to delay actual registration until uisetup or so

    For example, the decorator class to delay registration by
    'keyword' funcregistrar can be defined as below::

        class extkeyword(delayregistrar):
            registrar = keyword
    """
    def __init__(self):
        self._list = []

    registrar = None

    def __call__(self, *args, **kwargs):
        """Return the decorator to delay actual registration until setup
        """
        assert self.registrar is not None
        def decorator(func):
            # invocation of self.registrar() here can detect argument
            # mismatching immediately
            self._list.append((func, self.registrar(*args, **kwargs)))
            return func
        return decorator

    def setup(self):
        """Execute actual registration
        """
        while self._list:
            func, decorator = self._list.pop(0)
            decorator(func)