changelog: turn {de,en}code_extra methods into functions

changelog: turn {de,en}code_extra methods into functions

The methods were not really methods -- they didn't use 'self'. Having
them as functions in the module it useful for other modules (like the
commitsigs extension) that want to recompute the changeset hash and
thus want to encode dicts the same way as changelog does it.

Removed the underbars from their names at the same time.

--- a/mercurial/changelog.py	Sat May 16 11:16:23 2009 +0200
+++ b/mercurial/changelog.py	Fri May 15 01:21:24 2009 +0200
@@ -23,6 +23,19 @@
     text = text.replace('\\', '\\\\').replace('\n', '\\n').replace('\r', '\\r')
     return text.replace('\0', '\\0')
 
+def decodeextra(text):
+    extra = {}
+    for l in text.split('\0'):
+        if l:
+            k, v = l.decode('string_escape').split(':', 1)
+            extra[k] = v
+    return extra
+
+def encodeextra(d):
+    # keys must be sorted to produce a deterministic changelog entry
+    items = [_string_escape('%s:%s' % (k, d[k])) for k in sorted(d)]
+    return "\0".join(items)
+
 class appender:
     '''the changelog index must be updated last on disk, so we use this class
     to delay writes to it'''
@@ -145,19 +158,6 @@
             return
         return revlog.revlog.checkinlinesize(self, tr, fp)
 
-    def decode_extra(self, text):
-        extra = {}
-        for l in text.split('\0'):
-            if l:
-                k, v = l.decode('string_escape').split(':', 1)
-                extra[k] = v
-        return extra
-
-    def encode_extra(self, d):
-        # keys must be sorted to produce a deterministic changelog entry
-        items = [_string_escape('%s:%s' % (k, d[k])) for k in sorted(d)]
-        return "\0".join(items)
-
     def read(self, node):
         """
         format used:
@@ -192,7 +192,7 @@
         else:
             time, timezone, extra = extra_data
             time, timezone = float(time), int(timezone)
-            extra = self.decode_extra(extra)
+            extra = decodeextra(extra)
         if not extra.get('branch'):
             extra['branch'] = 'default'
         files = l[3:]
@@ -218,7 +218,7 @@
         if extra and extra.get("branch") in ("default", ""):
             del extra["branch"]
         if extra:
-            extra = self.encode_extra(extra)
+            extra = encodeextra(extra)
             parseddate = "%s %s" % (parseddate, extra)
         l = [hex(manifest), user, parseddate] + sorted(files) + ["", desc]
         text = "\n".join(l)