i18n: calculate terminal columns by width information of each characters
neither number of 'bytes' in any encoding nor 'characters' is
appropriate to calculate terminal columns for specified string.
this patch modifies MBTextWrapper for:
- overriding '_wrap_chunks()' to make it use not built-in 'len()'
but 'encoding.colwidth()' for columns of string
- fixing '_cutdown()' to make it use 'encoding.colwidth()' instead
of local, similar but incorrect implementation
this patch also modifies 'encoding.py':
- dividing 'colwith()' into 2 pieces: one for calculation columns of
specified UNICODE string, and another for rest part of original
one. the former is used from MBTextWrapper in 'util.py'.
- preventing 'colwidth()' from evaluating HGENCODINGAMBIGUOUS
configuration per each invocation: 'unicodedata.east_asian_width'
checking is kept intact for reducing startup cost.
# 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'
class localstr(str):
'''This class allows strings that are unmodified to be
round-tripped to the local encoding and back'''
def __new__(cls, u, l):
s = str.__new__(cls, l)
s._utf8 = u
return s
def __hash__(self):
return hash(self._utf8) # avoid collisions in local string space
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.
The localstr class is used to cache the known UTF-8 encoding of
strings next to their local representation to allow lossless
round-trip conversion back to UTF-8.
>>> u = 'foo: \\xc3\\xa4' # utf-8
>>> l = tolocal(u)
>>> l
'foo: ?'
>>> fromlocal(l)
'foo: \\xc3\\xa4'
>>> u2 = 'foo: \\xc3\\xa1'
>>> d = { l: 1, tolocal(u2): 2 }
>>> d # no collision
{'foo: ?': 1, 'foo: ?': 2}
>>> 'foo: ?' in d
False
>>> l1 = 'foo: \\xe4' # historical latin1 fallback
>>> l = tolocal(l1)
>>> l
'foo: ?'
>>> fromlocal(l) # magically in utf-8
'foo: \\xc3\\xa4'
"""
for e in ('UTF-8', fallbackencoding):
try:
u = s.decode(e) # attempt strict decoding
r = u.encode(encoding, "replace")
if u == r.decode(encoding):
# r is a safe, non-lossy encoding of s
return r
elif e == 'UTF-8':
return localstr(s, r)
else:
return localstr(u.encode('UTF-8'), r)
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") # can't round-trip
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.
"""
# can we do a lossless round-trip?
if isinstance(s, localstr):
return s._utf8
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.
wide = (os.environ.get("HGENCODINGAMBIGUOUS", "narrow") == "wide"
and "WFA" or "WF")
def colwidth(s):
"Find the column width of a UTF-8 string for display"
return ucolwidth(s.decode(encoding, 'replace'))
def ucolwidth(d):
"Find the column width of a Unicode string for display"
eaw = getattr(unicodedata, 'east_asian_width', None)
if eaw is not None:
return sum([eaw(c) in wide and 2 or 1 for c in d])
return len(d)
def lower(s):
"best-effort encoding-aware case-folding of local string s"
try:
if isinstance(s, localstr):
u = s._utf8.decode("utf-8")
else:
u = s.decode(encoding, encodingmode)
lu = u.lower()
if u == lu:
return s # preserve localstring
return lu.encode(encoding)
except UnicodeError:
return s.lower() # we don't know how to fold this except in ASCII