/distribution/libraries/Babel-1.0dev-py3.2/babel/util.py

# -*- coding: utf-8 -*-
#
# Copyright (C) 2007-2011 Edgewall Software
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://babel.edgewall.org/wiki/License.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://babel.edgewall.org/log/.

"""Various utility classes and functions."""

import codecs
from datetime import timedelta, tzinfo
import os
import re
import sys
import textwrap
import time

from babel.compat import PY3, binary_type, text_type, b

missing = object()

__all__ = ['distinct', 'pathmatch', 'relpath', 'wraptext', 'odict', 'UTC',
           'LOCALTZ']
__docformat__ = 'restructuredtext en'


def distinct(iterable):
    """Yield all items in an iterable collection that are distinct.

    Unlike when using sets for a similar effect, the original ordering of the
    items in the collection is preserved by this function.

    >>> print(list(distinct([1, 2, 1, 3, 4, 4])))
    [1, 2, 3, 4]
    >>> print(list(distinct('foobar')))
    ['f', 'o', 'b', 'a', 'r']

    :param iterable: the iterable collection providing the data
    :return: the distinct items in the collection
    :rtype: ``iterator``
    """
    seen = set()
    for item in iter(iterable):
        if item not in seen:
            yield item
            seen.add(item)

# Regexp to match python magic encoding line
PYTHON_MAGIC_COMMENT_re = re.compile(
    b(r'[ \t\f]* \# .* coding[=:][ \t]*([-\w.]+)'), re.VERBOSE)
def parse_encoding(fp):
    """Deduce the encoding of a source file from magic comment.

    It does this in the same way as the `Python interpreter`__

    .. __: http://docs.python.org/ref/encodings.html

    The ``fp`` argument should be a seekable file object.

    (From Jeff Dairiki)
    """
    pos = fp.tell()
    fp.seek(0)
    try:
        line1 = fp.readline()
        if isinstance(line1, text_type):
            line1 = line1.encode()
        has_bom = line1.startswith(codecs.BOM_UTF8)
        if has_bom:
            line1 = line1[len(codecs.BOM_UTF8):]

        m = PYTHON_MAGIC_COMMENT_re.match(line1)
        if not m:
            try:
                import parser
                parser.suite(line1.decode())
            except (ImportError, SyntaxError):
                # Either it's a real syntax error, in which case the source is
                # not valid python source, or line2 is a continuation of line1,
                # in which case we don't want to scan line2 for a magic
                # comment.
                pass
            else:
                line2 = fp.readline()
                if isinstance(line2, text_type):
                    line2 = line2.encode()
                m = PYTHON_MAGIC_COMMENT_re.match(line2)

        if has_bom:
            if m:
                raise SyntaxError(
                    "python refuses to compile code with both a UTF8 "
                    "byte-order-mark and a magic encoding comment")
            return 'utf_8'
        elif m:
            return m.group(1)
        else:
            return None
    finally:
        fp.seek(pos)

def pathmatch(pattern, filename):
    """Extended pathname pattern matching.
    
    This function is similar to what is provided by the ``fnmatch`` module in
    the Python standard library, but:
    
     * can match complete (relative or absolute) path names, and not just file
       names, and
     * also supports a convenience pattern ("**") to match files at any
       directory level.
    
    Examples:
    
    >>> pathmatch('**.py', 'bar.py')
    True
    >>> pathmatch('**.py', 'foo/bar/baz.py')
    True
    >>> pathmatch('**.py', 'templates/index.html')
    False
    
    >>> pathmatch('**/templates/*.html', 'templates/index.html')
    True
    >>> pathmatch('**/templates/*.html', 'templates/foo/bar.html')
    False
    
    :param pattern: the glob pattern
    :param filename: the path name of the file to match against
    :return: `True` if the path name matches the pattern, `False` otherwise
    :rtype: `bool`
    """
    symbols = {
        '?':   '[^/]',
        '?/':  '[^/]/',
        '*':   '[^/]+',
        '*/':  '[^/]+/',
        '**/': '(?:.+/)*?',
        '**':  '(?:.+/)*?[^/]+',
    }
    buf = []
    for idx, part in enumerate(re.split('([?*]+/?)', pattern)):
        if idx % 2:
            buf.append(symbols[part])
        elif part:
            buf.append(re.escape(part))
    match = re.match(''.join(buf) + '$', filename.replace(os.sep, '/'))
    return match is not None


class TextWrapper(textwrap.TextWrapper):
    wordsep_re = re.compile(
        r'(\s+|'                                  # any whitespace
        r'(?<=[\w\!\"\'\&\.\,\?])-{2,}(?=\w))'    # em-dash
    )


def wraptext(text, width=70, initial_indent='', subsequent_indent=''):
    """Simple wrapper around the ``textwrap.wrap`` function in the standard
    library. This version does not wrap lines on hyphens in words.
    
    :param text: the text to wrap
    :param width: the maximum line width
    :param initial_indent: string that will be prepended to the first line of
                           wrapped output
    :param subsequent_indent: string that will be prepended to all lines save
                              the first of wrapped output
    :return: a list of lines
    :rtype: `list`
    """
    wrapper = TextWrapper(width=width, initial_indent=initial_indent,
                          subsequent_indent=subsequent_indent,
                          break_long_words=False)
    return wrapper.wrap(text)

if sys.version_info >= (3, 1):
    import collections

    class odict(collections.OrderedDict):
        """
        Ordered dict implementation.
        As per PEP 372, an ordered dict was added to Python 3.1 and above
        Use that here, as the odict below did not work for py3.2
        """
        def __init__(self, data=None):
            collections.OrderedDict.__init__(self, data or {})
    
else:
    class odict(dict):
        """Ordered dict implementation.
        
        :see: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/107747
        """
        def __init__(self, data=None):
            dict.__init__(self, data or {})
            self._keys = dict.keys(self)

        def __delitem__(self, key):
            dict.__delitem__(self, key)
            self._keys.remove(key)

        def __setitem__(self, key, item):
            dict.__setitem__(self, key, item)
            if key not in self._keys:
                self._keys.append(key)

        def __iter__(self):
            return iter(self._keys)
        iterkeys = __iter__

        def clear(self):
            dict.clear(self)
            self._keys = []

        def copy(self):
            d = odict()
            d.update(self)
            return d

        def items(self):
            if PY3:
                return list(zip(self._keys, list(self.values())))
            else:
                return zip(self._keys, self.values())

        def iteritems(self):
            if PY3:
                return zip(self._keys, iter(self.values()))
            else:
                from itertools import izip
                return izip(self._keys, self.itervalues())

        def keys(self):
            return self._keys[:]

        def pop(self, key, default=missing):
            if default is missing:
                return dict.pop(self, key)
            elif key not in self:
                return default
            self._keys.remove(key)
            return dict.pop(self, key, default)

        def popitem(self, key):
            self._keys.remove(key)
            return dict.popitem(key)

        def setdefault(self, key, failobj = None):
            dict.setdefault(self, key, failobj)
            if key not in self._keys:
                self._keys.append(key)

        def update(self, dict):
            for (key, val) in dict.items():
                self[key] = val

        def values(self):
            if PY3:
                return list(map(self.get, self._keys))
            else:
                return map(self.get, self._keys)

        def itervalues(self):
            if PY3:
                return map(self.get, self._keys)
            else:
                from itertools import imap
                return imap(self.get, self._keys)


try:
    relpath = os.path.relpath
except AttributeError:
    def relpath(path, start='.'):
        """Compute the relative path to one path from another.
        
        >>> relpath('foo/bar.txt', '').replace(os.sep, '/')
        'foo/bar.txt'
        >>> relpath('foo/bar.txt', 'foo').replace(os.sep, '/')
        'bar.txt'
        >>> relpath('foo/bar.txt', 'baz').replace(os.sep, '/')
        '../foo/bar.txt'
        
        :return: the relative path
        :rtype: `basestring`
        """
        start_list = os.path.abspath(start).split(os.sep)
        path_list = os.path.abspath(path).split(os.sep)

        # Work out how much of the filepath is shared by start and path.
        i = len(os.path.commonprefix([start_list, path_list]))

        rel_list = [os.path.pardir] * (len(start_list) - i) + path_list[i:]
        return os.path.join(*rel_list)

ZERO = timedelta(0)


class FixedOffsetTimezone(tzinfo):
    """Fixed offset in minutes east from UTC."""

    def __init__(self, offset, name=None):
        self._offset = timedelta(minutes=offset)
        if name is None:
            name = 'Etc/GMT+%d' % offset
        self.zone = name

    def __str__(self):
        return self.zone

    def __repr__(self):
        return '<FixedOffset "%s" %s>' % (self.zone, self._offset)

    def utcoffset(self, dt):
        return self._offset

    def tzname(self, dt):
        return self.zone

    def dst(self, dt):
        return ZERO


try:
    from pytz import UTC
except ImportError:
    UTC = FixedOffsetTimezone(0, 'UTC')
    """`tzinfo` object for UTC (Universal Time).
    
    :type: `tzinfo`
    """

STDOFFSET = timedelta(seconds = -time.timezone)
if time.daylight:
    DSTOFFSET = timedelta(seconds = -time.altzone)
else:
    DSTOFFSET = STDOFFSET

DSTDIFF = DSTOFFSET - STDOFFSET


class LocalTimezone(tzinfo):

    def utcoffset(self, dt):
        if self._isdst(dt):
            return DSTOFFSET
        else:
            return STDOFFSET

    def dst(self, dt):
        if self._isdst(dt):
            return DSTDIFF
        else:
            return ZERO

    def tzname(self, dt):
        return time.tzname[self._isdst(dt)]

    def _isdst(self, dt):
        tt = (dt.year, dt.month, dt.day,
              dt.hour, dt.minute, dt.second,
              dt.weekday(), 0, -1)
        stamp = time.mktime(tt)
        tt = time.localtime(stamp)
        return tt.tm_isdst > 0


LOCALTZ = LocalTimezone()
"""`tzinfo` object for local time-zone.

:type: `tzinfo`
"""