[PATCH 09 of 22] obsstore: move header encoding to a separate function

[Jun Wu]

# HG changeset patch
# User Jun Wu <quark at fb.com>
# Date 1496561891 25200
#      Sun Jun 04 00:38:11 2017 -0700
# Node ID 5b83ced66577dc862594f85bcef2726a0d3fcfaf
# Parent  e42031df2e3a0a3805c13ade577a083117d745aa
# Available At https://bitbucket.org/quark-zju/hg-draft
#              hg pull https://bitbucket.org/quark-zju/hg-draft -r 5b83ced66577
obsstore: move header encoding to a separate function

This patch moves encodeheader from encodemarkers. So markers and header
could be encoded separately.

diff --git a/mercurial/obsolete.py b/mercurial/obsolete.py
--- a/mercurial/obsolete.py
+++ b/mercurial/obsolete.py
@@ -453,4 +453,7 @@ def _readmarkers(data):
     return diskversion, formats[diskversion][0](data, off)
 
+def encodeheader(version=_fm0version):
+    return _pack('>B', version)
+
 def encodemarkers(markers, addheader=False, version=_fm0version):
     # Kept separate from flushmarkers(), it will be reused for
@@ -458,5 +461,5 @@ def encodemarkers(markers, addheader=Fal
     encodeone = formats[version][1]
     if addheader:
-        yield _pack('>B', version)
+        yield encodeheader(version)
     for marker in markers:
         yield encodeone(marker)