[meld] Fix universal newline support on Windows (closes bgo#687729)

[Kai Willadsen <kaiw src gnome org>]

commit bba8939be770409b25f7bf9b1c4aca3032d79f19
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Apr 7 13:05:21 2013 +1000

    Fix universal newline support on Windows (closes bgo#687729)
    
    The codecs module uses and/or doesn't use Python's universal newline
    support in odd ways, and in particular breaks our assumptions on
    Windows. This patch changes from using the codecs module to using the
    newer io module to do the same job, with the bonus that this should be
    more forwards-compatible.

 meld/filediff.py |   18 +++++++++++-------
 1 files changed, 11 insertions(+), 7 deletions(-)
---
diff --git a/meld/filediff.py b/meld/filediff.py
index 3b73530..18bf137 100644
--- a/meld/filediff.py
+++ b/meld/filediff.py
@@ -16,9 +16,9 @@
 ### Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 ### USA.
 
-import codecs
 import copy
 import functools
+import io
 import os
 from gettext import gettext as _
 import time
@@ -1037,7 +1037,7 @@ class FileDiff(melddoc.MeldDoc, gnomeglade.Component):
             buf = textbuffers[pane]
             if filename:
                 try:
-                    handle = codecs.open(filename, "rU", try_codecs[0])
+                    handle = io.open(filename, "r", encoding=try_codecs[0])
                     task = TaskEntry(filename, handle, buf, try_codecs[:],
                                      pane, False)
                     tasks.append(task)
@@ -1062,7 +1062,7 @@ class FileDiff(melddoc.MeldDoc, gnomeglade.Component):
                     t.codec.pop(0)
                     if len(t.codec):
                         t.buf.delete(*t.buf.get_bounds())
-                        t.file = codecs.open(t.filename, "rU", t.codec[0])
+                        t.file = io.open(t.filename, "r", encoding=t.codec[0])
                     else:
                         t.buf.delete(*t.buf.get_bounds())
                         filename = gobject.markup_escape_text(t.filename)
@@ -1454,11 +1454,15 @@ class FileDiff(melddoc.MeldDoc, gnomeglade.Component):
         start, end = buf.get_bounds()
         text = text_type(buf.get_text(start, end, False), 'utf8')
         if bufdata.newlines:
-            if type(bufdata.newlines) == type(""):
-                if(bufdata.newlines) != '\n':
+            if isinstance(bufdata.newlines, basestring):
+                if bufdata.newlines != '\n':
                     text = text.replace("\n", bufdata.newlines)
-            elif type(bufdata.newlines) == type(()):
-                buttons = {'\n':("UNIX (LF)",0), '\r\n':("DOS (CR-LF)", 1), '\r':("MAC (CR)",2) }
+            else:
+                buttons = {
+                    '\n': ("UNIX (LF)", 0),
+                    '\r\n': ("DOS/Windows (CR-LF)", 1),
+                    '\r': ("Mac OS (CR)", 2),
+                }
                 newline = misc.run_dialog( _("This file '%s' contains a mixture of line endings.\n\nWhich 
format would you like to use?") % bufdata.label,
                     self, gtk.MESSAGE_WARNING, buttonstype=gtk.BUTTONS_CANCEL,
                     extrabuttons=[ buttons[b] for b in bufdata.newlines ] )