mercurial/i18n.py

ancestor: a new algorithm that is faster for nodes near tip

Instead of walking all the way to the root of the DAG, we generate
a set of candidate GCA revs, then figure out which ones will win
the race to the root (usually without needing to traverse all the
way to the root).

In the common case of nodes that are close to each other in both
revision number and topology, this is usually a big win: it makes
"hg --time debugancestors" up to 9 times faster than the more general
ancestor function when measured on heads of the linux-2.6 hg repo.

Victory is not assured, however. The older function can still win
by a large margin if one node is much closer to the root than the
other, or by a much smaller amount if one is an ancestor of the
other.

For now, we've also got a small paranoid harness function that calls
both ancestor functions on every input and ensures that they give
equivalent answers.

Even without the checker function, the old ancestor function needs
to stay alive for the time being, as its generality is used by
context.filectx.merge.

# i18n.py - internationalization support for mercurial
#
# Copyright 2005, 2006 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.

import encoding
import gettext, sys, os

# modelled after templater.templatepath:
if getattr(sys, 'frozen', None) is not None:
    module = sys.executable
else:
    module = __file__

base = os.path.dirname(module)
for dir in ('.', '..'):
    localedir = os.path.join(base, dir, 'locale')
    if os.path.isdir(localedir):
        break

t = gettext.translation('hg', localedir, fallback=True)

def gettext(message):
    """Translate message.

    The message is looked up in the catalog to get a Unicode string,
    which is encoded in the local encoding before being returned.

    Important: message is restricted to characters in the encoding
    given by sys.getdefaultencoding() which is most likely 'ascii'.
    """
    # If message is None, t.ugettext will return u'None' as the
    # translation whereas our callers expect us to return None.
    if message is None:
        return message

    paragraphs = message.split('\n\n')
    # Be careful not to translate the empty string -- it holds the
    # meta data of the .po file.
    u = u'\n\n'.join([p and t.ugettext(p) or '' for p in paragraphs])
    try:
        # encoding.tolocal cannot be used since it will first try to
        # decode the Unicode string. Calling u.decode(enc) really
        # means u.encode(sys.getdefaultencoding()).decode(enc). Since
        # the Python encoding defaults to 'ascii', this fails if the
        # translated string use non-ASCII characters.
        return u.encode(encoding.encoding, "replace")
    except LookupError:
        # An unknown encoding results in a LookupError.
        return message

def _plain():
    if 'HGPLAIN' not in os.environ and 'HGPLAINEXCEPT' not in os.environ:
        return False
    exceptions = os.environ.get('HGPLAINEXCEPT', '').strip().split(',')
    return 'i18n' not in exceptions

if _plain():
    _ = lambda message: message
else:
    _ = gettext