# HG changeset patch
# User Siddharth Agarwal <sid0@fb.com>
# Date 1358553316 28800
# Node ID ecba9b0e767254c2b241657a9b591a2480f5811c
# Parent  1f794204abbd7dd4bc329ae0c7c4fd7ce56b33af
posix: don't compare atime when determining if a file has changed

A file's atime might change even if the file itself doesn't change. This might
cause us to invalidate caches more often than necessary.

Before this change, hg add often resulted in the dirstate being parsed twice
on systems that track atime. After this change, it is only parsed once. For a
repository with over 180,000 files, this speeds up hg add from 1.2 seconds to
1.0.

diff -r 1f794204abbd -r ecba9b0e7672 mercurial/posix.py
--- a/mercurial/posix.py	Fri Oct 05 18:10:56 2012 -0500
+++ b/mercurial/posix.py	Fri Jan 18 15:55:16 2013 -0800
@@ -490,7 +490,20 @@
 
     def __eq__(self, other):
         try:
-            return self.stat == other.stat
+            # Only dev, ino, size, mtime and atime are likely to change. Out
+            # of these, we shouldn't compare atime but should compare the
+            # rest. However, one of the other fields changing indicates
+            # something fishy going on, so return False if anything but atime
+            # changes.
+            return (self.stat.st_mode == other.stat.st_mode and
+                    self.stat.st_ino == other.stat.st_ino and
+                    self.stat.st_dev == other.stat.st_dev and
+                    self.stat.st_nlink == other.stat.st_nlink and
+                    self.stat.st_uid == other.stat.st_uid and
+                    self.stat.st_gid == other.stat.st_gid and
+                    self.stat.st_size == other.stat.st_size and
+                    self.stat.st_mtime == other.stat.st_mtime and
+                    self.stat.st_ctime == other.stat.st_ctime)
         except AttributeError:
             return False