# HG changeset patch
# User Laurent Charignon <lcharignon@fb.com>
# Date 1450472085 28800
# Node ID ff305ab2e0d7291da12a8b640ce8c9bb28e0cb03
# Parent  ed003859f1d81d614fba98e5ca08dbcf5b0a7224
log: speed up hg log <file|folder>

This patch makes hg log <file|folder> faster by using changelog.readfiles
instead of changelog.read.
On our large repos for hg log <file|folder> -l5 operations that were taking:
- ~8s I see a 25% improvement
- ~15s, I see a 35% improvement
For recently modified folder/file, the difference is negligible as we don't
have to consider many revisions.

diff -r ed003859f1d8 -r ff305ab2e0d7 mercurial/revset.py
--- a/mercurial/revset.py	Fri Dec 18 13:45:55 2015 -0800
+++ b/mercurial/revset.py	Fri Dec 18 12:54:45 2015 -0800
@@ -1166,13 +1166,13 @@
 
     # This directly read the changelog data as creating changectx for all
     # revisions is quite expensive.
-    getchangeset = repo.changelog.read
+    getfiles = repo.changelog.readfiles
     wdirrev = node.wdirrev
     def matches(x):
         if x == wdirrev:
             files = repo[x].files()
         else:
-            files = getchangeset(x)[3]
+            files = getfiles(x)
         for f in files:
             if m(f):
                 return True