[PATCH 05 of 10 lazy-changelog-parse] changelog: lazily parse user

[Gregory Szorc]

# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1457303386 28800
#      Sun Mar 06 14:29:46 2016 -0800
# Node ID 5850dab8a22608aff069198e4d9e0157bbad6828
# Parent  a42fc3233c0886129c9e71b201f9f01880bf9e75
changelog: lazily parse user

Same strategy as before.

Revsets not accessing the user demonstrate a slight performance win:

desc(bug)
0.887169
0.910400
0.895514

date(2015)
0.878797
0.870697
0.820987

extra(rebase_source)
0.865446
0.841644
0.823811

date(2015) or branch(default)
0.968276
0.945792
0.910981

diff --git a/mercurial/changelog.py b/mercurial/changelog.py
--- a/mercurial/changelog.py
+++ b/mercurial/changelog.py
@@ -151,17 +151,17 @@ class changelogrevision(object):
     """
 
     __slots__ = (
         'date',
         '_rawdesc',
         'extra',
         'files',
         '_rawmanifest',
-        'user',
+        '_rawuser',
     )
 
     def __new__(cls, text):
         if not text:
             return _changelogrevision(
                 manifest=nullid,
                 user='',
                 date=(0, 0),
@@ -186,18 +186,20 @@ class changelogrevision(object):
         # changelog v0 doesn't use extra
 
         doublenl = text.index('\n\n')
         self._rawdesc = text[doublenl + 2:]
 
         nl1 = text.index('\n')
         self._rawmanifest = text[0:nl1]
 
+        nl2 = text.index('\n', nl1 + 1)
+        self._rawuser = text[nl1 + 1:nl2]
+
         l = text[:doublenl].split('\n')
-        self.user = encoding.tolocal(l[1])
 
         tdata = l[2].split(' ', 2)
         if len(tdata) != 3:
             time = float(tdata[0])
             try:
                 # various tools did silly things with the time zone field.
                 timezone = int(tdata[1])
             except ValueError:
@@ -212,16 +214,20 @@ class changelogrevision(object):
 
         return self
 
     @property
     def manifest(self):
         return bin(self._rawmanifest)
 
     @property
+    def user(self):
+        return encoding.tolocal(self._rawuser)
+
+    @property
     def description(self):
         return encoding.tolocal(self._rawdesc)
 
 class changelog(revlog.revlog):
     def __init__(self, opener):
         revlog.revlog.__init__(self, opener, "00changelog.i")
         if self._initempty:
             # changelogs don't benefit from generaldelta