mirror of
https://github.com/facebook/sapling.git
synced 2024-10-10 08:47:12 +03:00
7120dc2e96
39fbe33f95fa brought "asciilower" and "import parsers" into "encoding.py". This works fine with "parsers" module in C implementation, but doesn't with one in pure Python implementation, because the latter causes cyclic dependency below and aborting execution: util => i18n => encoding => parsers => util This patch delays importing "parsers" module until it is really needed, to avoid cyclic dependency around "parsers" in pure Python build.
439 lines
14 KiB
Python
439 lines
14 KiB
Python
# encoding.py - character transcoding support for Mercurial
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#
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# Copyright 2005-2009 Matt Mackall <mpm@selenic.com> and others
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2 or any later version.
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import error
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import unicodedata, locale, os
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def _getpreferredencoding():
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'''
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On darwin, getpreferredencoding ignores the locale environment and
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always returns mac-roman. http://bugs.python.org/issue6202 fixes this
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for Python 2.7 and up. This is the same corrected code for earlier
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Python versions.
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However, we can't use a version check for this method, as some distributions
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patch Python to fix this. Instead, we use it as a 'fixer' for the mac-roman
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encoding, as it is unlikely that this encoding is the actually expected.
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'''
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try:
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locale.CODESET
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except AttributeError:
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# Fall back to parsing environment variables :-(
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return locale.getdefaultlocale()[1]
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oldloc = locale.setlocale(locale.LC_CTYPE)
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locale.setlocale(locale.LC_CTYPE, "")
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result = locale.nl_langinfo(locale.CODESET)
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locale.setlocale(locale.LC_CTYPE, oldloc)
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return result
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_encodingfixers = {
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'646': lambda: 'ascii',
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'ANSI_X3.4-1968': lambda: 'ascii',
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'mac-roman': _getpreferredencoding
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}
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try:
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encoding = os.environ.get("HGENCODING")
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if not encoding:
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encoding = locale.getpreferredencoding() or 'ascii'
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encoding = _encodingfixers.get(encoding, lambda: encoding)()
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except locale.Error:
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encoding = 'ascii'
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encodingmode = os.environ.get("HGENCODINGMODE", "strict")
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fallbackencoding = 'ISO-8859-1'
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class localstr(str):
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'''This class allows strings that are unmodified to be
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round-tripped to the local encoding and back'''
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def __new__(cls, u, l):
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s = str.__new__(cls, l)
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s._utf8 = u
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return s
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def __hash__(self):
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return hash(self._utf8) # avoid collisions in local string space
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def tolocal(s):
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"""
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Convert a string from internal UTF-8 to local encoding
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All internal strings should be UTF-8 but some repos before the
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implementation of locale support may contain latin1 or possibly
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other character sets. We attempt to decode everything strictly
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using UTF-8, then Latin-1, and failing that, we use UTF-8 and
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replace unknown characters.
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The localstr class is used to cache the known UTF-8 encoding of
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strings next to their local representation to allow lossless
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round-trip conversion back to UTF-8.
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>>> u = 'foo: \\xc3\\xa4' # utf-8
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>>> l = tolocal(u)
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>>> l
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'foo: ?'
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>>> fromlocal(l)
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'foo: \\xc3\\xa4'
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>>> u2 = 'foo: \\xc3\\xa1'
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>>> d = { l: 1, tolocal(u2): 2 }
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>>> len(d) # no collision
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2
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>>> 'foo: ?' in d
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False
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>>> l1 = 'foo: \\xe4' # historical latin1 fallback
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>>> l = tolocal(l1)
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>>> l
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'foo: ?'
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>>> fromlocal(l) # magically in utf-8
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'foo: \\xc3\\xa4'
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"""
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try:
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try:
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# make sure string is actually stored in UTF-8
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u = s.decode('UTF-8')
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if encoding == 'UTF-8':
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# fast path
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return s
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r = u.encode(encoding, "replace")
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if u == r.decode(encoding):
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# r is a safe, non-lossy encoding of s
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return r
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return localstr(s, r)
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except UnicodeDecodeError:
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# we should only get here if we're looking at an ancient changeset
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try:
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u = s.decode(fallbackencoding)
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r = u.encode(encoding, "replace")
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if u == r.decode(encoding):
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# r is a safe, non-lossy encoding of s
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return r
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return localstr(u.encode('UTF-8'), r)
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except UnicodeDecodeError:
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u = s.decode("utf-8", "replace") # last ditch
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return u.encode(encoding, "replace") # can't round-trip
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except LookupError, k:
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raise error.Abort(k, hint="please check your locale settings")
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def fromlocal(s):
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"""
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Convert a string from the local character encoding to UTF-8
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We attempt to decode strings using the encoding mode set by
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HGENCODINGMODE, which defaults to 'strict'. In this mode, unknown
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characters will cause an error message. Other modes include
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'replace', which replaces unknown characters with a special
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Unicode character, and 'ignore', which drops the character.
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"""
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# can we do a lossless round-trip?
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if isinstance(s, localstr):
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return s._utf8
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try:
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return s.decode(encoding, encodingmode).encode("utf-8")
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except UnicodeDecodeError, inst:
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sub = s[max(0, inst.start - 10):inst.start + 10]
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raise error.Abort("decoding near '%s': %s!" % (sub, inst))
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except LookupError, k:
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raise error.Abort(k, hint="please check your locale settings")
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# How to treat ambiguous-width characters. Set to 'wide' to treat as wide.
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wide = (os.environ.get("HGENCODINGAMBIGUOUS", "narrow") == "wide"
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and "WFA" or "WF")
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def colwidth(s):
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"Find the column width of a string for display in the local encoding"
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return ucolwidth(s.decode(encoding, 'replace'))
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def ucolwidth(d):
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"Find the column width of a Unicode string for display"
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eaw = getattr(unicodedata, 'east_asian_width', None)
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if eaw is not None:
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return sum([eaw(c) in wide and 2 or 1 for c in d])
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return len(d)
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def getcols(s, start, c):
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'''Use colwidth to find a c-column substring of s starting at byte
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index start'''
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for x in xrange(start + c, len(s)):
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t = s[start:x]
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if colwidth(t) == c:
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return t
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def trim(s, width, ellipsis='', leftside=False):
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"""Trim string 's' to at most 'width' columns (including 'ellipsis').
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If 'leftside' is True, left side of string 's' is trimmed.
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'ellipsis' is always placed at trimmed side.
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>>> ellipsis = '+++'
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>>> from mercurial import encoding
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>>> encoding.encoding = 'utf-8'
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>>> t= '1234567890'
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>>> print trim(t, 12, ellipsis=ellipsis)
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1234567890
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>>> print trim(t, 10, ellipsis=ellipsis)
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1234567890
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>>> print trim(t, 8, ellipsis=ellipsis)
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12345+++
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>>> print trim(t, 8, ellipsis=ellipsis, leftside=True)
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+++67890
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>>> print trim(t, 8)
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12345678
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>>> print trim(t, 8, leftside=True)
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34567890
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>>> print trim(t, 3, ellipsis=ellipsis)
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+++
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>>> print trim(t, 1, ellipsis=ellipsis)
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+
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>>> u = u'\u3042\u3044\u3046\u3048\u304a' # 2 x 5 = 10 columns
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>>> t = u.encode(encoding.encoding)
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>>> print trim(t, 12, ellipsis=ellipsis)
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\xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88\xe3\x81\x8a
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>>> print trim(t, 10, ellipsis=ellipsis)
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\xe3\x81\x82\xe3\x81\x84\xe3\x81\x86\xe3\x81\x88\xe3\x81\x8a
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>>> print trim(t, 8, ellipsis=ellipsis)
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\xe3\x81\x82\xe3\x81\x84+++
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>>> print trim(t, 8, ellipsis=ellipsis, leftside=True)
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+++\xe3\x81\x88\xe3\x81\x8a
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>>> print trim(t, 5)
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\xe3\x81\x82\xe3\x81\x84
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>>> print trim(t, 5, leftside=True)
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\xe3\x81\x88\xe3\x81\x8a
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>>> print trim(t, 4, ellipsis=ellipsis)
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+++
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>>> print trim(t, 4, ellipsis=ellipsis, leftside=True)
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+++
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>>> t = '\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa' # invalid byte sequence
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>>> print trim(t, 12, ellipsis=ellipsis)
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\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa
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>>> print trim(t, 10, ellipsis=ellipsis)
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\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa
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>>> print trim(t, 8, ellipsis=ellipsis)
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\x11\x22\x33\x44\x55+++
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>>> print trim(t, 8, ellipsis=ellipsis, leftside=True)
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+++\x66\x77\x88\x99\xaa
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>>> print trim(t, 8)
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\x11\x22\x33\x44\x55\x66\x77\x88
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>>> print trim(t, 8, leftside=True)
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\x33\x44\x55\x66\x77\x88\x99\xaa
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>>> print trim(t, 3, ellipsis=ellipsis)
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+++
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>>> print trim(t, 1, ellipsis=ellipsis)
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+
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"""
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try:
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u = s.decode(encoding)
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except UnicodeDecodeError:
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if len(s) <= width: # trimming is not needed
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return s
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width -= len(ellipsis)
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if width <= 0: # no enough room even for ellipsis
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return ellipsis[:width + len(ellipsis)]
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if leftside:
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return ellipsis + s[-width:]
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return s[:width] + ellipsis
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if ucolwidth(u) <= width: # trimming is not needed
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return s
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width -= len(ellipsis)
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if width <= 0: # no enough room even for ellipsis
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return ellipsis[:width + len(ellipsis)]
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if leftside:
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uslice = lambda i: u[i:]
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concat = lambda s: ellipsis + s
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else:
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uslice = lambda i: u[:-i]
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concat = lambda s: s + ellipsis
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for i in xrange(1, len(u)):
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usub = uslice(i)
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if ucolwidth(usub) <= width:
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return concat(usub.encode(encoding))
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return ellipsis # no enough room for multi-column characters
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def _asciilower(s):
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'''convert a string to lowercase if ASCII
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Raises UnicodeDecodeError if non-ASCII characters are found.'''
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s.decode('ascii')
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return s.lower()
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def asciilower(s):
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# delay importing avoids cyclic dependency around "parsers" in
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# pure Python build (util => i18n => encoding => parsers => util)
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import parsers
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impl = getattr(parsers, 'asciilower', _asciilower)
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global asciilower
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asciilower = impl
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return impl(s)
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def lower(s):
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"best-effort encoding-aware case-folding of local string s"
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try:
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return asciilower(s)
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except UnicodeDecodeError:
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pass
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try:
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if isinstance(s, localstr):
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u = s._utf8.decode("utf-8")
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else:
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u = s.decode(encoding, encodingmode)
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lu = u.lower()
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if u == lu:
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return s # preserve localstring
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return lu.encode(encoding)
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except UnicodeError:
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return s.lower() # we don't know how to fold this except in ASCII
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except LookupError, k:
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raise error.Abort(k, hint="please check your locale settings")
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def upper(s):
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"best-effort encoding-aware case-folding of local string s"
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try:
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s.decode('ascii') # throw exception for non-ASCII character
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return s.upper()
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except UnicodeDecodeError:
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pass
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try:
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if isinstance(s, localstr):
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u = s._utf8.decode("utf-8")
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else:
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u = s.decode(encoding, encodingmode)
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uu = u.upper()
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if u == uu:
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return s # preserve localstring
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return uu.encode(encoding)
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except UnicodeError:
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return s.upper() # we don't know how to fold this except in ASCII
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except LookupError, k:
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raise error.Abort(k, hint="please check your locale settings")
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_jsonmap = {}
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def jsonescape(s):
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'''returns a string suitable for JSON
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JSON is problematic for us because it doesn't support non-Unicode
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bytes. To deal with this, we take the following approach:
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- localstr objects are converted back to UTF-8
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- valid UTF-8/ASCII strings are passed as-is
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- other strings are converted to UTF-8b surrogate encoding
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- apply JSON-specified string escaping
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(escapes are doubled in these tests)
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>>> jsonescape('this is a test')
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'this is a test'
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>>> jsonescape('escape characters: \\0 \\x0b \\t \\n \\r \\" \\\\')
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'escape characters: \\\\u0000 \\\\u000b \\\\t \\\\n \\\\r \\\\" \\\\\\\\'
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>>> jsonescape('a weird byte: \\xdd')
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'a weird byte: \\xed\\xb3\\x9d'
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>>> jsonescape('utf-8: caf\\xc3\\xa9')
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'utf-8: caf\\xc3\\xa9'
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>>> jsonescape('')
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''
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'''
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if not _jsonmap:
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for x in xrange(32):
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_jsonmap[chr(x)] = "\u%04x" %x
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for x in xrange(32, 256):
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c = chr(x)
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_jsonmap[c] = c
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_jsonmap['\t'] = '\\t'
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_jsonmap['\n'] = '\\n'
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_jsonmap['\"'] = '\\"'
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_jsonmap['\\'] = '\\\\'
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_jsonmap['\b'] = '\\b'
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_jsonmap['\f'] = '\\f'
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_jsonmap['\r'] = '\\r'
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return ''.join(_jsonmap[c] for c in toutf8b(s))
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def toutf8b(s):
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'''convert a local, possibly-binary string into UTF-8b
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This is intended as a generic method to preserve data when working
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with schemes like JSON and XML that have no provision for
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arbitrary byte strings. As Mercurial often doesn't know
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what encoding data is in, we use so-called UTF-8b.
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If a string is already valid UTF-8 (or ASCII), it passes unmodified.
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Otherwise, unsupported bytes are mapped to UTF-16 surrogate range,
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uDC00-uDCFF.
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Principles of operation:
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- ASCII and UTF-8 data successfully round-trips and is understood
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by Unicode-oriented clients
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- filenames and file contents in arbitrary other encodings can have
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be round-tripped or recovered by clueful clients
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- local strings that have a cached known UTF-8 encoding (aka
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localstr) get sent as UTF-8 so Unicode-oriented clients get the
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Unicode data they want
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- because we must preserve UTF-8 bytestring in places such as
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filenames, metadata can't be roundtripped without help
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(Note: "UTF-8b" often refers to decoding a mix of valid UTF-8 and
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arbitrary bytes into an internal Unicode format that can be
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re-encoded back into the original. Here we are exposing the
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internal surrogate encoding as a UTF-8 string.)
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'''
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if isinstance(s, localstr):
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return s._utf8
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try:
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s.decode('utf-8')
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return s
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except UnicodeDecodeError:
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# surrogate-encode any characters that don't round-trip
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s2 = s.decode('utf-8', 'ignore').encode('utf-8')
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r = ""
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pos = 0
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for c in s:
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if s2[pos:pos + 1] == c:
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r += c
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pos += 1
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else:
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r += unichr(0xdc00 + ord(c)).encode('utf-8')
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return r
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def fromutf8b(s):
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'''Given a UTF-8b string, return a local, possibly-binary string.
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return the original binary string. This
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is a round-trip process for strings like filenames, but metadata
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that's was passed through tolocal will remain in UTF-8.
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>>> m = "\\xc3\\xa9\\x99abcd"
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>>> n = toutf8b(m)
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>>> n
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'\\xc3\\xa9\\xed\\xb2\\x99abcd'
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>>> fromutf8b(n) == m
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True
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'''
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# fast path - look for uDxxx prefixes in s
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if "\xed" not in s:
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return s
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u = s.decode("utf-8")
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r = ""
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for c in u:
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if ord(c) & 0xff00 == 0xdc00:
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r += chr(ord(c) & 0xff)
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else:
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r += c.encode("utf-8")
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return r
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