mercurial/encoding.py

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mercurial/encoding.py	Fri Apr 03 14:51:48 2009 -0500
@@ -0,0 +1,77 @@
+"""
+encoding.py - character transcoding support for Mercurial
+
+ Copyright 2005-2009 Matt Mackall <[e-mail]> and others
+
+This software may be used and distributed according to the terms of
+the GNU General Public License version 2, incorporated herein by
+reference.
+"""
+
+import sys, unicodedata, locale, os, error
+
+_encodingfixup = {'646': 'ascii', 'ANSI_X3.4-1968': 'ascii'}
+
+try:
+    encoding = os.environ.get("HGENCODING")
+    if sys.platform == 'darwin' and not encoding:
+        # On darwin, getpreferredencoding ignores the locale environment and
+        # always returns mac-roman. We override this if the environment is
+        # not C (has been customized by the user).
+        locale.setlocale(locale.LC_CTYPE, '')
+        encoding = locale.getlocale()[1]
+    if not encoding:
+        encoding = locale.getpreferredencoding() or 'ascii'
+        encoding = _encodingfixup.get(encoding, 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)
+
+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'):
+        w = unicodedata.east_asian_width
+        return sum([w(c) in 'WF' and 2 or 1 for c in d])
+    return len(d)
+