# HG changeset patch
# User Siddharth Agarwal <sid0@fb.com>
# Date 1397529137 25200
# Node ID 96f0463a4e54f454e770a5cddea6f0a199e43267
# Parent  96458acb160a1615bd9565e7908f36e6641ad6d7
revset_gitnode: use repo.changelog.node instead of contexts

For a repository with around 60,000 commits, perfrevset for gitnode becomes:
before: ! wall 1.130716 comb 1.130000 user 1.130000 sys 0.000000 (best of 9)
after:  ! wall 0.178828 comb 0.180000 user 0.180000 sys 0.000000 (best of 54)

In reality, perfrevset doesn't clear the Git-to-Mercurial map, which means that
a call like `hg log -r 'gitnode(...)'` speeds up from around 1.5 seconds to
0.6.

diff --git a/hggit/__init__.py b/hggit/__init__.py
--- a/hggit/__init__.py
+++ b/hggit/__init__.py
@@ -31,6 +31,7 @@
 from mercurial import hg
 from mercurial import ignore
 from mercurial import localrepo
+from mercurial.node import hex
 from mercurial import revset
 from mercurial import templatekw
 from mercurial import util as hgutil
@@ -200,8 +201,9 @@
     rev = revset.getstring(args[0],
                            "the argument to gitnode() must be a hash")
     git = repo.githandler
+    node = repo.changelog.node
     def matches(r):
-        gitnode = git.map_git_get(repo[r].hex())
+        gitnode = git.map_git_get(hex(node(r)))
         if gitnode is None:
             return False
         return rev in [gitnode, gitnode[:12]]