[PATCH 5 of 9] changelog: use "vfs.fstat()" instead of "util.fstat()"

[FUJIWARA Katsunori]

# HG changeset patch
# User FUJIWARA Katsunori <foozy at lares.dti.ne.jp>
# Date 1381765864 -32400
#      Tue Oct 15 00:51:04 2013 +0900
# Node ID 07ebc40aa3695dfbf03ae13bb1662f784266bcab
# Parent  2be31b7a1e81f9b6ce8f20c1fd221e1eea3117a7
changelog: use "vfs.fstat()" instead of "util.fstat()"

Just invoking "os.fstat()" with "file.fileno()" doesn't require non
ANSI file API, because filename is not used for invocation of
"os.fstat()".

But "util.fstat()" should invoke "os.stat()" with "fp.name", if file
object doesn't have "fileno()" method for portability, and "fp.name"
may cause invocation of non ANSI file API.

So, this patch makes the constructor of appender class invoke
"util.fstat()" via vfs, to encapsulate filename handling.

diff --git a/mercurial/changelog.py b/mercurial/changelog.py
--- a/mercurial/changelog.py
+++ b/mercurial/changelog.py
@@ -59,11 +59,12 @@
 class appender(object):
     '''the changelog index must be updated last on disk, so we use this class
     to delay writes to it'''
-    def __init__(self, fp, buf):
+    def __init__(self, vfs, name, mode, buf):
         self.data = buf
+        fp = vfs(name, mode)
         self.fp = fp
         self.offset = fp.tell()
-        self.size = util.fstat(fp).st_size
+        self.size = vfs.fstat(fp).st_size
 
     def end(self):
         return self.size + len("".join(self.data))
@@ -114,7 +115,7 @@
         if divert:
             return opener(name + ".a", mode.replace('a', 'w'))
         # otherwise, divert to memory
-        return appender(opener(name, mode), buf)
+        return appender(opener, name, mode, buf)
     return o
 
 class changelog(revlog.revlog):
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -245,6 +245,9 @@
     def exists(self, path=None):
         return os.path.exists(self.join(path))
 
+    def fstat(self, fp):
+        return util.fstat(fp)
+
     def isdir(self, path=None):
         return os.path.isdir(self.join(path))