sapling/mercurial/encoding.py
Matt Mackall 50b99d1a5a encoding: default ambiguous character to narrow
The current implementation of colwidth was treating 'A'mbiguous
characters as wide, which was incorrect in a non-East Asian context.
As per http://unicode.org/reports/tr11/#Recommendations, we should
instead default to 'narrow' if we don't know better. As character
width is dependent on the particular font used and we have no idea
what fonts are in use, this recommendation applies.

This introduces HGENCODINGAMBIGUOUS to get the old behavior back.
2010-10-27 15:35:21 -05:00

104 lines
3.6 KiB
Python

# encoding.py - character transcoding support for Mercurial
#
# Copyright 2005-2009 Matt Mackall <mpm@selenic.com> 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.
import error
import unicodedata, locale, os
def _getpreferredencoding():
'''
On darwin, getpreferredencoding ignores the locale environment and
always returns mac-roman. http://bugs.python.org/issue6202 fixes this
for Python 2.7 and up. This is the same corrected code for earlier
Python versions.
However, we can't use a version check for this method, as some distributions
patch Python to fix this. Instead, we use it as a 'fixer' for the mac-roman
encoding, as it is unlikely that this encoding is the actually expected.
'''
try:
locale.CODESET
except AttributeError:
# Fall back to parsing environment variables :-(
return locale.getdefaultlocale()[1]
oldloc = locale.setlocale(locale.LC_CTYPE)
locale.setlocale(locale.LC_CTYPE, "")
result = locale.nl_langinfo(locale.CODESET)
locale.setlocale(locale.LC_CTYPE, oldloc)
return result
_encodingfixers = {
'646': lambda: 'ascii',
'ANSI_X3.4-1968': lambda: 'ascii',
'mac-roman': _getpreferredencoding
}
try:
encoding = os.environ.get("HGENCODING")
if not encoding:
encoding = locale.getpreferredencoding() or 'ascii'
encoding = _encodingfixers.get(encoding, lambda: encoding)()
except locale.Error:
encoding = 'ascii'
encodingmode = os.environ.get("HGENCODINGMODE", "strict")
fallbackencoding = 'ISO-8859-1'
def tolocal(s):
"""
Convert a string from internal UTF-8 to local encoding
All internal strings should be UTF-8 but some repos before the
implementation of locale support may contain latin1 or possibly
other character sets. We attempt to decode everything strictly
using UTF-8, then Latin-1, and failing that, we use UTF-8 and
replace unknown characters.
"""
for e in ('UTF-8', fallbackencoding):
try:
u = s.decode(e) # attempt strict decoding
return u.encode(encoding, "replace")
except LookupError, k:
raise error.Abort("%s, please check your locale settings" % k)
except UnicodeDecodeError:
pass
u = s.decode("utf-8", "replace") # last ditch
return u.encode(encoding, "replace")
def fromlocal(s):
"""
Convert a string from the local character encoding to UTF-8
We attempt to decode strings using the encoding mode set by
HGENCODINGMODE, which defaults to 'strict'. In this mode, unknown
characters will cause an error message. Other modes include
'replace', which replaces unknown characters with a special
Unicode character, and 'ignore', which drops the character.
"""
try:
return s.decode(encoding, encodingmode).encode("utf-8")
except UnicodeDecodeError, inst:
sub = s[max(0, inst.start - 10):inst.start + 10]
raise error.Abort("decoding near '%s': %s!" % (sub, inst))
except LookupError, k:
raise error.Abort("%s, please check your locale settings" % k)
# How to treat ambiguous-width characters. Set to 'wide' to treat as wide.
ambiguous = os.environ.get("HGENCODINGAMBIGUOUS", "narrow")
def colwidth(s):
"Find the column width of a UTF-8 string for display"
d = s.decode(encoding, 'replace')
if hasattr(unicodedata, 'east_asian_width'):
wide = "WF"
if ambiguous == "wide":
wide = "WFA"
w = unicodedata.east_asian_width
return sum([w(c) in wide and 2 or 1 for c in d])
return len(d)